98 results on '"Ji XD"'
Search Results
2. Mechanism of Qili Qiangxin Capsule for Heart Failure Based on miR133a-Endoplasmic Reticulum Stress.
- Author
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Ji XD, Yang D, Cui XY, Lou LX, Nie B, Zhao JL, Zhao MJ, and Wu AM
- Subjects
- Animals, Male, Rats, Sprague-Dawley, Capsules, Activating Transcription Factor 6 metabolism, Activating Transcription Factor 6 genetics, Endoplasmic Reticulum Chaperone BiP, Apoptosis drug effects, Caspase 12 metabolism, Caspase 12 genetics, Myocardium pathology, Myocardium metabolism, Heat-Shock Proteins metabolism, Heat-Shock Proteins genetics, Rats, X-Box Binding Protein 1 metabolism, X-Box Binding Protein 1 genetics, Protein Serine-Threonine Kinases metabolism, Protein Serine-Threonine Kinases genetics, Myocardial Infarction drug therapy, Myocardial Infarction pathology, Myocardial Infarction genetics, Myocardial Infarction physiopathology, MicroRNAs genetics, MicroRNAs metabolism, Endoplasmic Reticulum Stress drug effects, Drugs, Chinese Herbal pharmacology, Heart Failure drug therapy, Heart Failure genetics
- Abstract
Objective: To investigate the pharmacological mechanism of Qili Qiangxin Capsule (QLQX) improvement of heart failure (HF) based on miR133a-endoplasmic reticulum stress (ERS) pathway., Methods: A left coronary artery ligation-induced HF after myocardial infarction model was used in this study. Rats were randomly assigned to the sham group, the model group, the QLQX group [0.32 g/(kg·d)], and the captopril group [2.25 mg/(kg·d)], 15 rats per group, followed by 4 weeks of medication. Cardiac function such as left ventricular ejection fraction (EF), fractional shortening (FS), left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), the maximal rate of increase of left ventricular pressure (+dp/dt max), and the maximal rate of decrease of left ventricular pressure (-dp/dt max) were monitored by echocardiography and hemodynamics. Hematoxylin and eosin (HE) and Masson stainings were used to visualize pathological changes in myocardial tissue. The mRNA expression of miR133a, glucose-regulated protein78 (GRP78), inositol-requiring enzyme 1 (IRE1), activating transcription factor 6 (ATF6), X-box binding protein1 (XBP1), C/EBP homologous protein (CHOP) and Caspase 12 were detected by RT-PCR. The protein expression of GRP78, p-IRE1/IRE1 ratio, cleaved-ATF6, XBP1-s (the spliced form of XBP1), CHOP and Caspase 12 were detected by Western blot. TdT-mediated dUTP nick-end labeling (TUNEL) staining was used to detect the rate of apoptosis., Results: QLQX significantly improved cardiac function as evidenced by increased EF, FS, LVSP, +dp/dt max, -dp/dt max, and decreased LVEDP (P<0.05, P<0.01). HE staining showed that QLQX ameliorated cardiac pathologic damage to some extent. Masson staining indicated that QLQX significantly reduced collagen volume fraction in myocardial tissue (P<0.01). Results from RT-PCR and Western blot showed that QLQX significantly increased the expression of miR133a and inhibited the mRNA expressions of GRP78, IRE1, ATF6 and XBP1, as well as decreased the protein expressions of GRP78, cleaved-ATF6 and XBP1-s and decreased p-IRE1/IRE1 ratio (P<0.05, P<0.01). Further studies showed that QLQX significantly reduced the expression of CHOP and Caspase12, resulting in a significant reduction in apoptosis rate (P<0.05, P<0.01)., Conclusion: The pharmacological mechanism of QLQX in improving HF is partly attributed to its regulatory effect on the miR133a-IRE1/XBP1 pathway., (© 2024. The Chinese Journal of Integrated Traditional and Western Medicine Press and Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2024
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3. Established sensitization of ethanol-induced locomotor activity is not reversed by psilocybin or the 5-HT 2A receptor agonist TCB-2 in male DBA/2J mice.
- Author
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Fletcher PJ, Li Z, Ji XD, and Lê AD
- Subjects
- Male, Animals, Mice, Mice, Inbred DBA, Psilocybin, Receptor, Serotonin, 5-HT2A, Motor Activity, Ethanol pharmacology, Hallucinogens pharmacology
- Abstract
Rationale: Psychedelic drugs, which share in common 5-HT
2A receptor agonist activity, have shown promise in treating alcohol-use disorders (AUDs). Repeated exposure to ethanol (EtOH) induces molecular and behavioural changes reflective of neuroadaptations that may contribute to addiction. Psychedelic drugs can induce neuroplasticity also, raising the possibility that their potential clinical effects in AUD may involve an action to reverse or offset effects of long-term changes induced by EtOH. This possibility was examined by investigating whether psilocybin, or the 5-HT2A receptor agonist TCB-2, counteracted established sensitization of EtOH-induced locomotor activity., Methods: Male DBA/2J mice received repeated injections of 2.2 g/kg EtOH to induce a sensitized locomotor activity response. In two experiments separate groups of mice were then injected with psilocybin (0, 0.3 and 1 kg/kg) or TCB-2 (0, 1 and 3 mg/kg) on 5 consecutive days. Next, mice were challenged with 1.8 g/kg EtOH and locomotor activity measured for 15 min., Results: Relative to naïve controls, previously sensitized mice showed enhanced locomotor activity to the challenge dose. Despite reducing locomotor activity in their own right psilocybin and TCB-2 did not alter the strength of this sensitized response., Conclusion: Psilocybin and TCB-2 at behaviourally effective doses did not reverse sensitization of EtOH-induced activity. This suggests that mechanisms involved in mediating short-term reductions in EtOH intake by psilocybin or TCB-2 may not involve a capacity of these drugs to offset enduring changes in behaviour and any underlying neural adaptations induced by repeated intermittent exposure to EtOH., (Copyright © 2023 Elsevier Inc. All rights reserved.)- Published
- 2024
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4. Long-term outcomes of endoscopic papillary large-balloon dilation (12-15 mm) with or without limited sphincterotomy for removal of bile duct stones.
- Author
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Li T, Hao LX, Lv C, Li XJ, Ji XD, Chen M, Liu C, Bie LK, and Gong B
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- Humans, Retrospective Studies, Dilatation, Treatment Outcome, Cholangiopancreatography, Endoscopic Retrograde adverse effects, Cholangiopancreatography, Endoscopic Retrograde methods, Sphincterotomy, Endoscopic adverse effects, Sphincterotomy, Endoscopic methods, Gallstones diagnostic imaging, Gallstones surgery, Choledocholithiasis diagnostic imaging, Choledocholithiasis surgery
- Abstract
Background: Limited endoscopic sphincterotomy with large balloon dilation (ES-LBD) and endoscopic papillary large-balloon dilation (EPLBD) have been proven safe and effective for removal of bile duct stones. However, the long-term outcomes are not clear. The aim of this study was to assess the long-term outcomes of EPLBD (12-15 mm) with or without limited sphincterotomy for removal of common bile duct (CBD) stones., Methods: Patients with EPLBD or ES-LBD referred for the removal of bile-duct stones between June 2008 and August 2020 were retrospectively reviewed. Complete stone clearance, endoscopic retrograde cholangiopancreatography (ERCP)-related adverse events, and late biliary complications during long-term follow-up were analyzed., Results: Basic patient characteristics were not significantly different between the groups that underwent EPLBD (n = 168) and ES-LBD (n = 57). EPLBD compared with ES-LBD resulted in similar outcomes in terms of overall successful stone removal (99.4% vs. 100%, P = 1.00) and ERCP-related adverse events (7.7% vs. 5.3%, P = 0.77). The mean duration of the follow-up were 113.6 months and 106.7 months for patients with EPLBD and ES-LBD, respectively (P = 0.13). There was no significant difference between EPLBD and ES-LBD in the incidence of stone recurrence [20 (11.9%) vs. 9 (15.8%); P = 0.49]. Multivariate analysis showed that a diameter of CBD ≥ 15 mm (OR = 3.001; 95% CI: 1.357-6.640; P = 0.007) was an independent risk factor for stone recurrence., Conclusions: The application of a large balloon (12-15 mm) via EPLBD is an effective and safe alternative to ES-LBD for extraction of large CBD stones. Endoscopic sphincterotomy prior to EPLBD may be unnecessary. A diameter of CBD ≥ 15 mm is a risk factor of stone recurrence., (Copyright © 2022. Published by Elsevier B.V.)
- Published
- 2023
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5. Over-activation of EFTUD2 correlates with tumor propagation and poor survival outcomes in hepatocellular carcinoma.
- Author
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Lv C, Li XJ, Hao LX, Zhang S, Song Z, Ji XD, and Gong B
- Subjects
- Animals, Cells, Cultured, Correlation of Data, Female, Humans, Male, Mice, Mice, Nude, Middle Aged, Neoplasm Invasiveness, Survival Rate, Carcinoma, Hepatocellular etiology, Carcinoma, Hepatocellular mortality, Carcinoma, Hepatocellular pathology, Liver Neoplasms etiology, Liver Neoplasms mortality, Liver Neoplasms pathology, Peptide Elongation Factors physiology, Ribonucleoprotein, U5 Small Nuclear physiology
- Abstract
Purpose: Elongation factor Tu GTP-binding domain containing 2 (EFTUD2) is an essential constituent of U5 small nuclear ribonucleoproteins (snRNPs) and plays a crucial role in spliceosome activation and cancer. The mechanism of EFTUD2 on carcinogenesis and development of liver cancer still need further study., Methods: Bioinformatic analysis was performed to find differential expressed genes and related pathways. Western blotting and quantitative PCR assays were used to verify the EFTUD2 expression in HCC cell lines and tumor tissues of liver cancer patients. Transfection of shRNAs in SKHEP1 and Huh7 cell lines was conducted to explore the mechanisms of EFTUD2 in HCC. CCK-8 method, colony formation, and cell cycle detection kit were used to detect the proliferation. A tumor model in nude mice was used to explore the role of EFTUD2 in liver cancer in vivo., Results: Based on the tumor tissues and para-tumor tissues in our HCC patients, we identified EFTUD2 as highly expressed in HCC tissues (P < 0.001). Bioinformatic analysis from the TCGA database also supported this biological phenomenon (P = 1.911e-17). Furtherly, the results of clinical specimens and TCGA data suggested that higher EFTUD2 expression levels correlated with high histologic grades, high pathological grades, and poor survival prognoses in HCC patients. And knockdown of EFTUD2 suppressed cell proliferation and colony formation in vitro. In vivo, knockdown of EFTUD2 constrained the tumor growing and expansion derived from SKHEP1 cells and induced a decrease in the tumor volume and tumor weight resected from nude mice. Furthermore, RNA sequencing based on EFTUD2 knockdown revealed that EFTUD2 affected target genes concerned with the cell cycle. Flow cytometric analyses in the SKHEP1 cell model revealed that knockdown significantly suppressed cell cycle course and caused cell cycle arrest in the G1 phase. CyclinD1 proteins were also inhibited by knocking down of EFTUD2., Conclusion: EFTUD2 is markedly overexpressed in HCC tumor tissues. High EFTUD2 expression in HCC patients is associated with clinical features. Moreover, we confirmed that EFTUD2 shows a pivotal role in HCC cell proliferation and cell cycle course and could be a possible therapeutic avenue in HCC through disturbing EFTUD2., (© 2021. Federación de Sociedades Españolas de Oncología (FESEO).)
- Published
- 2022
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6. Whole-body magnetic resonance imaging vs. clinical evaluation of enthesitis in patients with spondyloarthritis.
- Author
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Guo ZK, Zhang YM, Kong CY, Liu Y, Ji XD, Zhan Y, Qi WF, and Lei XW
- Subjects
- Humans, Severity of Illness Index, Whole Body Imaging, Magnetic Resonance Imaging, Spondylarthritis diagnostic imaging
- Published
- 2021
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7. 3D Finite Element Modeling of Blast Wave Transmission from the External Ear to Cochlea.
- Author
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Brown MA, Ji XD, and Gan RZ
- Subjects
- Blast Injuries, Finite Element Analysis, Hearing Loss, Humans, Male, Middle Aged, Cochlea, Ear Canal, Explosions, Models, Biological, Tympanic Membrane
- Abstract
As an organ that is sensitive to pressure changes, the ear is often damaged when a person is subjected to blast exposures resulting in hearing loss due to tissue damage in the middle ear and cochlea. While observation of middle ear damage is non-invasive, examining the damage to the cochlea is difficult to quantify. Previous works have modeled the cochlear response often when subjected to an acoustic pressure input, but the inner ear mechanics have rarely been studied when the ear is exposed to a blast wave. In this study we aim to develop a finite element (FE) model of the entire ear, particularly the cochlea, for predicting the blast wave transmission from the ear canal to cochlea. We utilized a FE model of the ear, which includes the ear canal, middle ear, and uncoiled two-chambered cochlea, to simulate the cochlear response to blast overpressure (BOP) at the entrance of the ear canal with ANSYS Mechanical and Fluent in a fluid-structure interface coupled analysis in the time domain. This model was developed based on previous middle and inner ear models, and the cochlea was remeshed to improve BOP simulation performance. The FE model was validated using experimentally measured blast pressure transduction from the ear canal to the middle ear and cochlea in human cadaveric temporal bones. Results from the FE model showed significant displacements of the tympanic membrane, middle ear ossicles, and basilar membrane (BM). The stapes footplate displacement was observed to be as high as 60 µm, far exceeding the displacement during normal acoustic stimulation, when the 30 kPa (4.35 psi, 183 dB (SPL), Sound Pressure Level) of BOP was applied at the ear canal entrance. The large stapes movement caused pressures in the cochlea to exceed the physiological pressure level [< 10 Pa, 120 dB (SPL)] at a peak of 49.9 kPa, and the BM displacement was on the order of microns with a maximum displacement of 26.4 µm. The FE model of the entire human ear developed in this study provides a computational tool for prediction of blast wave transmission from the ear canal to cochlea and the future applications for assisting the prevention, diagnosis, and treatment of blast-induced hearing loss.
- Published
- 2021
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8. Shikonin Inhibits Cholangiocarcinoma Cell Line QBC939 by Regulating Apoptosis, Proliferation, and Invasion.
- Author
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Liu C, Xuan LQ, Li K, Feng Z, Lv C, Li XJ, Ji XD, Wan R, and Shen J
- Subjects
- Anti-Inflammatory Agents, Non-Steroidal pharmacology, Apoptosis, Cell Line, Tumor, Cell Proliferation, Humans, Naphthoquinones pharmacology, Neoplasm Invasiveness, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Cholangiocarcinoma drug therapy, Naphthoquinones therapeutic use
- Abstract
This study was designed to clarify whether Shikonin causes proliferation, apoptosis, and invasion in cholangiocarcinoma cells and to investigate the mechanism of action. QBC939 cells were cultured with different doses of Shikonin, and then 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium assay was used to detect cell viability. Apoptosis of cells was detected using flow cytometry with Annexin V/propidium iodide (PI) assay after being stained with Hoechst 33242. The role of Shikonin on the invasive and metastasis ability was detected using Transwell invasion assay. Real-time polymerase chain reaction and Western blotting were used to detect the expression of caspase-3, caspase-8, epidermal growth factor receptor (EGFR), and matrix metalloproteinase (MMP)-9. Shikonin inhibited proliferation and invasive ability of QBC939 cells in a dose-dependent manner; at the same time, apoptosis of cells was also observed in a concentration-dependent fashion. Moreover, Annexin V/PI assay and Transwell invasion assay results indicated that Shikonin induced apoptosis and invasion inhibitory probably due to upregulation of caspase-3 and caspase-8 expression and downregulation of MMP-9 and EGFR expression in a concentration-dependent fashion. Shikonin could enhance apoptosis and inhibit proliferation and invasion of QBC939 cells; such biological behaviors mainly occurred via upregulating the expression of caspase-3 and caspase-8 and downregulating the expression of MMP-9 and EGFR.
- Published
- 2021
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9. Pathologic comparisons of enucleated eyes with retinoblastoma after superselective ophthalmic arterial chemotherapy with or without intravenous chemotherapy.
- Author
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Zhu XY, Li J, Guan WB, Chen CL, Ji XD, and Zhao PQ
- Abstract
Aim: To describe and compare pathologic findings in eyes enucleated after superselective ophthalmic arterial chemotherapy (SOAC) or SOAC with intravenous chemotherapy (IVC) for retinoblastoma., Methods: Medical records between January 1
st , 2014 and June 30th , 2017 were retrospectively analyzed, and pathologic findings were recorded. This study included 36 eyes from 22 (61.1%) male and 14 (38.9%) female patients. Nineteen of 36 (52.8%) eyes received SOAC (mean=3, range=1-7) as primary treatment, and 17 of 36 (47.2%) eyes received SOAC (mean=3.7, range=1-10) after IVC (mean=6.1, range=2-11). Tumor extension including choroidal invasion ( n =9, 25%), optic nerve invasion ( n =5, 13.9%) and anterior segment invasion ( n =5, 13.9%) were recorded., Results: Histopathologic evidence of ischemic damage in the retina and choroid was found in 28 (77.8%) eyes. Thrombosed blood vessels were identified in 9 (25%) eyes, including orbital artery in the retrobulbar orbit ( n =1), intrascleral vessels ( n =4), and chorioretinal vessels ( n =6). Fibrotic changes were found in extraocular muscles ( n =5, 13.9%) and optic nerve ( n =5, 13.9%). Varying degrees of scleral degeneration were found in all eyes. In statistical analysis, there was no significant difference in clinical and pathologic changes between SOAC group and SOAC with IVC group except for optic nerve invasion ( P =0.047)., Conclusion: SOAC for retinoblastoma can result in ocular toxicity, and SOAC with IVC do not increase the toxicity but reduced the incidence of optic nerve invasion., (International Journal of Ophthalmology Press.)- Published
- 2020
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10. Median raphe serotonin neurons promote anxiety-like behavior via inputs to the dorsal hippocampus.
- Author
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Abela AR, Browne CJ, Sargin D, Prevot TD, Ji XD, Li Z, Lambe EK, and Fletcher PJ
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- Animals, Anxiety genetics, Anxiety psychology, Channelrhodopsins analysis, Channelrhodopsins genetics, Channelrhodopsins metabolism, Female, Hippocampus chemistry, Locomotion physiology, Maze Learning physiology, Mice, Mice, Transgenic, Optogenetics methods, Organ Culture Techniques, Raphe Nuclei chemistry, Serotonergic Neurons chemistry, Anxiety metabolism, Hippocampus metabolism, Raphe Nuclei metabolism, Serotonergic Neurons metabolism
- Abstract
Anxiety disorders may be mediated in part by disruptions in serotonin (5-hydroxytryptamine, 5-HT) system function. Behavioral measures of approach-avoidance conflict suggest that serotonin neurons within the median raphe nucleus (MRN) promote an anxiogenic state, and some evidence indicates this may be mediated by serotonergic signaling within the dorsal hippocampus. Here, we test this hypothesis using an optogenetic approach to examine the contribution of MRN 5-HT neurons and 5-HT innervation of the dorsal hippocampus (dHC) to anxiety-like behaviours in female mice. Mice expressing the excitatory opsin ChR2 were generated by crossing the ePet-cre serotonergic cre-driver line with the conditional Ai32 ChR2 reporter line, resulting in selective expression of ChR2 in 5-HT neurons. Electrophysiological recordings confirmed that this approach enabled reliable optogenetic stimulation of MRN 5-HT neurons, and this stimulation produced downstream 5-HT release in the dHC as measured by in vivo microdialysis. Optogenetic stimulation of the MRN elicited behavioral responses indicative of an anxiogenic effect in three behavioural tests: novelty-suppressed feeding, marble burying and exploration on the elevated-plus maze. These effects were shown to be behaviourally-specific. Stimulation of 5-HT terminals in the dHC recapitulated the anxiety-like behaviour in the novelty-suppressed feeding and marble burying tests. These results show that activation of 5-HT efferents from the MRN rapidly induces expression of anxiety-like behaviour, in part via projections to the dHC. These findings reveal an important neural circuit implicated in the expression of anxiety in female mice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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11. Clozapine reliably increases the motivation for food: parsing the role of the 5-HT 2c and H 1 receptors.
- Author
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Abela AR, Ji XD, Li Z, Lê AD, and Fletcher PJ
- Subjects
- Animals, Eating drug effects, Eating physiology, Eating psychology, Feeding Behavior drug effects, Feeding Behavior psychology, Male, Motivation drug effects, Rats, Rats, Sprague-Dawley, Reinforcement Schedule, Serotonin Antagonists pharmacology, Weight Gain drug effects, Weight Gain physiology, Antipsychotic Agents pharmacology, Clozapine pharmacology, Feeding Behavior physiology, Motivation physiology, Receptor, Serotonin, 5-HT2C physiology, Receptors, Serotonin, 5-HT1 physiology
- Abstract
Rationale and Objectives: Although clozapine is effective in treating schizophrenia, it is associated with adverse side effects including weight gain and metabolic syndrome. Despite this, the role of clozapine on feeding behaviour and food intake has not been thoroughly characterised. Clozapine has a broad pharmacological profile, with affinities for several neurotransmitter receptors, including serotonin (5-hydroxytriptamine, 5-HT) and histamine. Given that the serotonin 5-HT
2C receptor and histaminergic H1 receptor are involved in aspects of feeding behaviour, the effect of clozapine on feeding may be linked to its action at these receptors., Methods: We assessed, in rats, the effect of acute and subchronic administration of clozapine on responding for food under a progressive ratio (PR) schedule under conditions of food restriction and satiety. We also examined the effect of antagonists of the serotonin 5-HT2C and histaminergic H1 receptors on the same schedule. Clozapine reliably increased responding for food, even when rats had ad libitum access to food. The effect of clozapine on responding for food was reproduced by combined (but not individual) antagonism of the serotonin 5-HT2C and histaminergic H1 receptors., Conclusion: These findings show that clozapine enhances the motivation to work for food, that this effect is stable over repeated testing, and is independent of hunger state of the animal. This effect may relate to a combined action of clozapine at the serotonin 5-HT2C and histaminergic H1 receptors.- Published
- 2020
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12. Combined intra-arterial chemotherapy and intravitreal melphalan for the treatment of advanced unilateral retinoblastoma.
- Author
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Liang TY, Zhu XY, Hua XM, Ji XD, and Zhao PQ
- Abstract
Aim: To evaluate the efficacy and safety of combined intra-arterial chemotherapy (IAC) and intravitreal melphalan (IVM) for the treatment of advanced unilateral retinoblastoma., Methods: This retrospective study involved 30 consecutive eyes from 30 Chinese patients with advanced unilateral retinoblastoma. All patients were initially treated with IAC combined with IVM. The clinical status and complications were recorded at each visit., Results: The International Intraocular Retinoblastoma Classification groups were D in 23 eyes and E in 7 eyes. All eyes showed severe cloud vitreous seeds at the first visit. The mean number of IAC cycles and intravitreal injections was 3.2 (range, 3-4) and 6 (range, 1-14), respectively. The median follow-up time was 29mo (range, 7-36mo). Treatment success with regression of the retinal tumor and vitreous seeds was achieved in 29 of 30 eyes (96.7%). Globe salvage was attained in 93.3% (28/30) eyes, and enucleation ( n =2) was performed due to neovascular glaucoma and persistent vitreous hemorrhage. Complications included retinal pigment epithelium (RPE) atrophy ( n =13; 43%), mild lens opacity ( n =7; 23%), vitreous hemorrhage ( n =5; 17%) and rhegmatogenous retinal detachment ( n =1; 3%). No extraocular tumor extension or metastasis occurred., Conclusion: Combined IAC and IVM is effective and safe for the treatment of advanced unilateral retinoblastoma., (International Journal of Ophthalmology Press.)
- Published
- 2020
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13. [The correlation between findings of whole-body diffusion weighted imaging and clinical result in patients with multiple myeloma].
- Author
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Huang WY, Yang M, Sui WW, Deng SH, Liu W, Ji XD, Zou DH, Hao M, Qiu LG, and Xia S
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- Adult, Aged, Diffusion Magnetic Resonance Imaging, Female, Human Body, Humans, Male, Middle Aged, Retrospective Studies, Spine, Multiple Myeloma
- Abstract
Objective: To explore the relationship between the findings of whole body diffusion weighted imaging (WBDWI) and the clinical result in patients with multiple myeloma. Methods: A total of 43 cases of multiple myeloma patients were retrospectively collected from May 2015 to May 2017 in Tianjin First Central Hospital.Twenty-nine cases were male and 14 were female. The median age was 54 years old with a range from 36 to 73 years old. The patients were divided into two groups with and without abnormal findings pending on whole body diffusion weighted imaging. The clinical data and the ADC value were compared between the two groups, as well as comparison in patients with abnormal findings between pre-and post-treatment. Results: In 43 patients, normal findings on WBDWI were found in 10 cases, 7 males, 3 females, age (59±9) years old, and abnormal findings in 33 cases, 22 males, 11 females, age (57±10) years old.No statistical differences of age and gender were found between two groups ( P> 0.05) .The ratio of plasma cells and the proportion of β(2) microspheres in patients with abnormal WBDWI (50.0% (14.0%, 78.0%) , 4.8 (2.7, 7.7) mg/L)were significantly higher than those in the normal group(5.0% (2.5%, 15.0%) , 2.4 (2.0, 3.7) mg/L) ( P< 0.05).ADC value in different body parts of abnormal group including costal ((0.66±0.15)×10(-3) mm(2)/s), sternal bone((0.71±0.20)×10(-3) mm(2)/s), clavicles((0.67±0.17)×10(-3) mm(2)/s), thoracic vertebra((0.63±0.17)×10(-3) mm(2)/s), lumber vertebra((0.69±0.20)×10(-3) mm(2)/s), pelvic((0.83±0.36)×10(-3) mm(2)/s), proximal humerus((0.76±0.13)×10(-3) mm(2)/s), proximal femur((0.64±0.17)×10(-3) mm(2)/s), shaft of femur((0.70±0.22)×10(-3) mm(2)/s), proximal tibia((0.97±0.18)×10(-3) mm(2)/s), shaft of tibia((0.83±0.18)×10(-3) mm(2)/s) which were significantly higher than those of normal group (all P< 0.05). The albumin concentration of the patients after treatment was significantly higher than those before treatment ( P< 0.05). Conclusion: Different imaging findings on WBDWI can reflect clinical different result in patients with multiple myeloma, and when WBDWI is normal, the clinical symptoms are mild. When abnormal findings detected on WBDWI, the clinical symptoms are still severe although albumin concentration increased after treatment.
- Published
- 2019
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14. Characterization of Protection Mechanisms to Blast Overpressure for Personal Hearing Protection Devices - Biomechanical Measurement and Computational Modeling.
- Author
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Gan RZ, Leckness K, Smith K, and Ji XD
- Subjects
- Cadaver, Equipment Design standards, Hearing Loss, Noise-Induced prevention & control, Humans, Pressure adverse effects, Tympanic Membrane injuries, Tympanic Membrane physiology, Biomechanical Phenomena, Computer Simulation, Ear Protective Devices standards, Explosions
- Abstract
Hearing damage induced by blast exposure is a common injury in military personnel involved in most operation activities. Personal hearing protection devices such as earplugs come as a standard issue for Service members; however, it is not clear how to accurately evaluate the protection mechanisms of different hearing protection devices for blast overpressures (BOP). This paper reports a recent study on characterization of earplugs' protective function to BOP using human cadaver ears and 3D finite element (FE) model of the human ear. The cadaver ear mounted with pressure sensors near the eardrum (P1) and inside the middle ear (P2) and with an earplug inserted was exposed to BOP in the blast test chamber. P1, P2, and BOP at the ear canal entrance (P0) were simultaneously recorded. The measured P0 waveform was then applied at the ear canal entrance in the FE model and the P1 and P2 pressures were derived from the model. Both experiments and FE modeling resulted in the P1 reduction which represents the effective protection function of the earplug. Different earplugs showed variations in pressure waveforms transmitted to the eardrum, which determine the protection level of earplugs., (© Association of Military Surgeons of the United States 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2019
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15. Biomechanical Measurement and Modeling of Human Eardrum Injury in Relation to Blast Wave Direction.
- Author
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Gan RZ, Leckness K, Nakmali D, and Ji XD
- Subjects
- Biomechanical Phenomena physiology, Computer Simulation statistics & numerical data, Explosions statistics & numerical data, Humans, Tympanic Membrane injuries, Tympanic Membrane physiopathology, Tympanic Membrane Perforation etiology, Blast Injuries physiopathology, Tympanic Membrane Perforation classification, Weights and Measures
- Abstract
Rupture of the eardrum or tympanic membrane (TM) is one of the most frequent injuries of the ear after blast exposure. To understand how the TM damage is related to blast wave direction, human cadaver ears were exposed to blast waves along three directions: vertical, horizontal, and front with respect to the head. Blast overpressure waveforms were recorded at the ear canal entrance (P0), near the TM (P1), and inside the middle ear (P2). Thirteen to fourteen cadaver ears were tested in each wave direction and the TM rupture thresholds were identified. Results show that blast wave direction affected the peak P1/P0 ratio, TM rupture threshold, and energy flux distribution over frequencies. The front wave resulted in lowest TM rupture threshold and the horizontal wave resulted in highest P1/P0 ratio. To investigate the mechanisms of TM injury in relation to blast wave direction, the recorded P1 waveforms were applied onto the surface of the TM in a three-dimensional finite element model of the human ear and distributions of the stress in TM were calculated. Modeling results indicate that the sensitivity of TM stress change with respect to P1 pressure (dσ/dP1) may characterize mechanical damage of the TM in relation to blast waves.
- Published
- 2018
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16. Simultaneous removal of aqueous Zn 2+ , Cu 2+ , Cd 2+ , and Pb 2+ by zeolites synthesized from low-calcium and high-calcium fly ash.
- Author
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Ji XD, Ma YY, Peng SH, Gong YY, and Zhang F
- Subjects
- Adsorption, Cadmium chemistry, Coal Ash, Copper chemistry, Hydrogen-Ion Concentration, Kinetics, Lead chemistry, Spectrometry, X-Ray Emission, Wastewater analysis, Water Purification methods, Zinc chemistry, Calcium chemistry, Metals, Heavy chemistry, Water Pollutants, Chemical chemistry, Zeolites chemistry
- Abstract
In this study, zeolites were synthesized from low-calcium (LCZ) and high-calcium (HCZ) fly ash, respectively. Subsequently, the zeolites were tested for their removal effectiveness for four aqueous cations, namely, Zn
2+ , Cu2+ , Cd2+ , and Pb2+ , as a function of contact time, pH value, adsorbent dosage, and initial concentration of heavy metals. Both zeolites were characterized by X-ray diffraction, X-ray fluorescence spectrometry, scanning electron microscopy, specific surface area, and cation exchange capacity. The results show that HCZ mainly consists of an unnamed zeolite (Na6 [AlSiO4 ]6 ·4H2 O), whereas LCZ mainly consists of faujasite-type zeolite. The optimum sorption conditions were pH = 6.0; adsorbent dosage = 1.0 g·L-1 ; temperature = 25 °C; contact time = 100 min; and initial heavy metal concentration = 100 mg·L-1 . The sorption kinetics of the four aqueous cations on both LCZ and HCZ followed the pseudo-second-order kinetic model, and the sorption isotherm data fitted well with the Langmuir isotherm model. For LCZ, the maximum adsorption capacities of Zn2+ , Cu2+ , Cd2+ , and Pb2+ were 155.76, 197.86, 123.76, and 186.22 mg·g-1 , respectively. For HCZ, the values were 154.08, 183.15, 118.91, and 191.94 mg·g-1 , respectively. The zeolites were regenerated by NaCl solution (1 mol·L-1 ) and showed high removal efficiency. In conclusion, zeolites produced by fly ash are promising materials for removing Zn2+ , Cu2+ , Cd2+ , and Pb2+ from wastewater.- Published
- 2017
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17. An international survey of classification and treatment choices for group D retinoblastoma.
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Scelfo C, Francis JH, Khetan V, Jenkins T, Marr B, Abramson DH, Shields CL, Pe'er J, Munier F, Berry J, Harbour JW, Yarovoy A, Lucena E, Murray TG, Bhagia P, Paysse E, Tuncer S, Chantada GL, Moll AC, Ushakova T, Plager DA, Ziyovuddin I, Leal CA, Materin MA, Ji XD, Cursino JW, Polania R, Kiratli H, All-Ericsson C, Kebudi R, Honavar SG, Vishnevskia-Dai V, Epelman S, Daniels AB, Ling JD, Traore F, and Ramirez-Ortiz MA
- Abstract
Aim: To determine which IIRC scheme was used by retinoblastoma centers worldwide and the percentage of D eyes treated primarily with enucleation versus globe salvaging therapies as well as to correlate trends in treatment choice to IIRC version used and geographic region., Methods: An anonymized electronic survey was offered to 115 physicians at 39 retinoblastoma centers worldwide asking about IIRC classification schemes and treatment patterns used between 2008 and 2012. Participants were asked to record which version of the IIRC was used for classification, how many group D eyes were diagnosed, and how many eyes were treated with enucleation versus globe salvaging therapies. Averages of eyes per treatment modality were calculated and stratified by both IIRC version and geographic region. Statistical significance was determined by Chi-square, ANOVA and Kruskal-Wallis tests using Prism., Results: The survey was completed by 29% of physicians invited to participate. Totally 1807 D eyes were diagnosed. Regarding IIRC system, 27% of centers used the Children's Hospital of Los Angeles (CHLA) version, 33% used the Children's Oncology Group (COG) version, 23% used the Philadelphia version, and 17% were unsure. The rate for primary enucleation varied between 0 and 100% and the mean was 29%. By IIRC version, primary enucleation rates were: Philadelphia, 8%; COG, 34%; and CHLA, 37%. By geographic region, primary enucleation rates were: Latin America, 57%; Asia, 40%; Europe, 36%; Africa, 10%, US, 8%; and Middle East, 8%. However, systemic chemoreduction was used more often than enucleation in all regions except Latin America with a mean of 57% per center ( P <0.0001)., Conclusion: Worldwide there is no consensus on which IIRC version is used, systemic chemoreduction was the most frequently used initial treatment during the study period followed by enucleation and primary treatment modality, especially enucleation, varied greatly with regards to IIRC version used and geographic region.
- Published
- 2017
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18. Recurrence of Retinopathy of Prematurity After Intravitreal Ranibizumab Monotherapy: Timing and Risk Factors.
- Author
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Lyu J, Zhang Q, Chen CL, Xu Y, Ji XD, Li JK, Huang QJ, and Zhao PQ
- Subjects
- Angiogenesis Inhibitors administration & dosage, Dose-Response Relationship, Drug, Female, Follow-Up Studies, Humans, Infant, Newborn, Intravitreal Injections, Male, Ophthalmoscopy, Prognosis, Recurrence, Retinopathy of Prematurity pathology, Retrospective Studies, Risk Factors, Time Factors, Vascular Endothelial Growth Factor A antagonists & inhibitors, Ranibizumab administration & dosage, Retina pathology, Retinopathy of Prematurity drug therapy
- Abstract
Purpose: To investigate timing and risk factors of recurrent retinopathy of prematurity (ROP) after intravitreal ranibizumab (IVR) monotherapy., Methods: Fifty eyes (the more severe eye) of 50 infants treated with IVR monotherapy for type 1 ROP were studied retrospectively. The mean follow-up time was 31 weeks after IVR. Recurrent ROP (recurrence of extraretinal fibrovascular proliferation [EFP]) was determined by RetCam wide-angle fundus imaging and binocular indirect ophthalmoscopy. Risk time of recurrence was estimated by Kaplan-Meier survival analysis with recurrence as the endpoint. Time-varying recurrence hazard rate was determined using the hazard function of life-table analysis. The risk factors of recurrence were explored by logistic regression analysis., Results: Recurrence of ROP occurred in 32 (64%) of 50 eyes at 7.9 ± 2.7 weeks after IVR. Most of recurrence (94%) occurred in 2.5 to 12.0 weeks following IVR treatment. The recurrence hazard rate reached its maximum at 8 weeks. Recurrence affecting the initial site of EFP occurred significantly earlier than recurrence only at the new vascular advancing edge (4.5 ± 1.4 weeks versus 9.1 ± 2.0 weeks after IVR, P < 0.001). The independent risk factors of recurrence included extensive retinal neovascularization (P = 0.005) and oxygen requirement after IVR (P = 0.016)., Conclusions: Recurrence of type 1 ROP should be carefully watched in a long-term follow-up after IVR monotherapy, particularly in the first 12 weeks after IVR and for those with extensive retinal neovascularization or prolonged oxygen therapy.
- Published
- 2017
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19. Depression, caregiver burden and social support among caregivers of retinoblastoma patients in China.
- Author
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Wang LJ, Zhong WX, Ji XD, and Chen J
- Subjects
- Adult, China, Female, Humans, Male, Prevalence, Caregivers psychology, Depression epidemiology, Retinoblastoma nursing, Social Support
- Abstract
The aim of this study is to examine the burden of family caregivers of patients with retinoblastoma in China and the relationships between depression, caregiver burden and social support. A descriptive and correlational survey was conducted with 117 Chinese family caregivers of outpatient patients with retinoblastoma from the Department of Ophthalmology of a tertiary hospital in Shanghai, China. Family caregivers of outpatient patients with retinoblastoma were asked to respond to four questionnaires including sociodemographic questionnaire, Becker Depression Inventory, Caregiver Burden Inventory and Social Support Rating Scale. The incidence of depression in this study was 51.3%; the average score for social support indicated moderate social support available to the caregivers, although their level of caregiver burden was heavy. Depression scores were significantly positively correlated with caregiver burden scores and significantly negatively correlated with the social support scores. Heavy caregiver burden was associated with lower monthly income, low subjective social support and less use of social support., (© 2016 John Wiley & Sons Australia, Ltd.)
- Published
- 2016
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20. Mechanical damage of tympanic membrane in relation to impulse pressure waveform - A study in chinchillas.
- Author
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Gan RZ, Nakmali D, Ji XD, Leckness K, and Yokell Z
- Subjects
- Animals, Elastic Modulus, Finite Element Analysis, Imaging, Three-Dimensional, Stress, Mechanical, Blast Injuries, Chinchilla, Evoked Potentials, Auditory, Brain Stem, Pressure adverse effects, Tympanic Membrane injuries
- Abstract
Mechanical damage to middle ear components in blast exposure directly causes hearing loss, and the rupture of the tympanic membrane (TM) is the most frequent injury of the ear. However, it is unclear how the severity of injury graded by different patterns of TM rupture is related to the overpressure waveforms induced by blast waves. In the present study, the relationship between the TM rupture threshold and the impulse or overpressure waveform has been investigated in chinchillas. Two groups of animals were exposed to blast overpressure simulated in our lab under two conditions: open field and shielded with a stainless steel cup covering the animal head. Auditory brainstem response (ABR) and wideband tympanometry were measured before and after exposure to check the hearing threshold and middle ear function. Results show that waveforms recorded in the shielded case were different from those in the open field and the TM rupture threshold in the shielded case was lower than that in the open field (3.4 ± 0.7 vs. 9.1 ± 1.7 psi or 181 ± 1.6 vs. 190 ± 1.9 dB SPL). The impulse pressure energy spectra analysis of waveforms demonstrates that the shielded waveforms include greater energy at high frequencies than that of the open field waves. Finally, a 3D finite element (FE) model of the chinchilla ear was used to compute the distributions of stress in the TM and the TM displacement with impulse pressure waves. The FE model-derived change of stress in response to pressure loading in the shielded case was substantially faster than that in the open case. This finding provides the biomechanical mechanisms for blast induced TM damage in relation to overpressure waveforms. The TM rupture threshold difference between the open and shielded cases suggests that an acoustic role of helmets may exist, intensifying ear injury during blast exposure., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
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21. A delayed diagnosis of unsuspected retinoblastoma in an in vitro fertilisation infant with retinopathy of prematurity.
- Author
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Tian T, Ji XD, Zhang Q, Peng J, and Zhao PQ
- Published
- 2016
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22. [Case-control study on locking titanium plate in treating comminuted proximal humeral fracture in elderly].
- Author
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Shi ZK, Jiang YB, Ji XD, and Jin C
- Subjects
- Aged, Aged, 80 and over, Case-Control Studies, Female, Humans, Male, Middle Aged, Titanium, Bone Plates, Fractures, Comminuted surgery, Shoulder Fractures surgery
- Abstract
Objective: To observe therapeutic effects of locking titanium plate for the treatment of comminuted proximal humeral fracture in elderly., Methods: From June 2011 to May 2013, 72 elderly patients with comminuted proximal humeral- fractures were divided into locking titanium plate group and anatomical plate group, 36 cases in each group. In locking titanium plate group, there were 16 males and 20 females aged from 60 to 79 years old with an average of (69.55±5.62) years old; 10 cases were type Neer II, 18 were type Neer III and 8 cases were type Neer IV in accordance with Neer classification; treated with locking titanium plate. In anatomical plate group, there were 15 males and 21 females aged from 60 to 81 years old with an average of (69.76±5.70) years old; 9 cases were type Neer II, 20 were type Neer III and 7 cases were type Neer IV; and treated with anatomical plate. Clinical effects, preoperative and postoperative Neer scoring, operative time, bone healing time and incidence of complications between two groups were compared., Results: All patients were followed up from 1 to 3 years with an average of 15 months. The excellent and good rate of locking titanium plate group (91.7%) was significantly higher than anatomical plate group (75.0%). Postoperative Neer score of two groups were improved obviously, but locking titanium plate group (92.51±7.85) was higher than anatomical plate group (83.64±8.56); there was no significant differences between two groups in operative time (P>0.05); bone healing time in locking titanium plate was (18.6±3.4) weeks, and shorter than anatomical plate group (24.3±3.9) weeks; incidence of complications in locking titanium plate was (5.6%) shorter than anatomical plate group (22.2%), and had obviously differences between two groups., Conclusion: Locking titanium plate for the treatment of comminuted proximal humeral fracture in elderly plays an important role in good rate, bone healing time and Neer score. It has advantages of early rehabilitation exercise, less shoulder pain, rapid recovery of shoulder joint, less complications, safe and effective, and be worthy of clinical application, especially for senile osteoporosis patients.
- Published
- 2014
23. Vitrectomy for localized vitreous seeds of retinoblastoma in an only eye.
- Author
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Ji XD, Lu SL, and Zhao PQ
- Subjects
- Eye Enucleation, Humans, Infant, Retinal Neoplasms surgery, Retinoblastoma surgery, Vitrectomy
- Published
- 2013
24. Simultaneous immobilization of ammonium and phosphate from aqueous solution using zeolites synthesized from fly ashes.
- Author
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Ji XD, Zhang ML, Ke YY, and Song YC
- Subjects
- Adsorption, Calcium chemistry, Hydrogen-Ion Concentration, Kinetics, Silicon Dioxide chemistry, Thermodynamics, Wastewater chemistry, Coal Ash chemistry, Phosphates isolation & purification, Quaternary Ammonium Compounds isolation & purification, Water Pollutants, Chemical isolation & purification, Zeolites chemical synthesis
- Abstract
Zeolites were synthesized from silica-rich (SF-Z) and calcium-rich (CF-Z) fly ashes, respectively, and their performance in immobilizing ammonium and phosphate was investigated through batch experiments. The cation exchange capacity and phosphate immobilization capacity of SF-Z were identified as 2.79 meq/g and 12.97 mg/g while those of CF-Z were 0.69 meq/g and 87.41 mg/g, respectively. The mixture of SF-Z and CF-Z (MSC-Z) immobilized simultaneously ammonium and phosphate, and the ratio of SF-Z to CF-Z depended on the ammonium and phosphate concentrations in wastewater and the discharge standard. The adsorption processes of ammonium and phosphate on MSC-Z followed Ho's pseudo-second-order model and the intra-particle diffusion was a rate-controlling step. The Langmuir model produced better suitability to the equilibrium data. The thermodynamic study revealed that the adsorption of both ammonium and phosphate on MSC-Z was an endothermic reaction. After treatment by MSC-Z, the ammonium and phosphate concentrations in wastewater from a sewage treatment plant decreased from 7.45 and 1.42 mg/L to 2.06 and 0.51 mg/L, respectively, and met Surface Water Environment Quality Standard in China δ. These results show that the immobilization of ammonium and phosphate in wastewater can be achieved by the combination of zeolites synthesized from silica-rich and calcium-rich fly ashes.
- Published
- 2013
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25. [Expression changes of tumor metastasis-related genes after overexpression of KAI1 in retinoblastoma Y79 cells].
- Author
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Ji XD, Yan H, and Zhao PQ
- Subjects
- Cell Line, Tumor, Gene Expression Regulation, Neoplastic, Humans, Neoplasm Metastasis, Retinoblastoma genetics, Retinoblastoma pathology, Kangai-1 Protein metabolism, Retinoblastoma metabolism
- Abstract
Objective: To investigate the expression changes of tumor metastasis-related genes after overexpression of KAI1 in retinoblastoma Y79 cells., Methods: Experimental study. Y79 cells were transfected with a lentivirus vector containing KAI1 and enhanced green fluorescent protein (EGFP) fusion gene, or a control lentivirus vector containing EGFP. Positive transfectants stably expressing high levels of KAI1 were named Y79-KAI1 and control transfectants were named Y79-KAI1/zero. These transfectants were selected by puromycin resistance and analysis with fluorescent microscopy. The expression of KAI1 mRNA and its protein among Y79, Y79-KAI1 and Y79-KAI1/zero were detected by fluorescent quantitative RT-PCR and Western blot. Differential expression of tumor metastasis-related genes in Y79-KAI1 and Y79-KAI1/zero was analyzed with human tumor metastasis PCR array. One-way ANOVA was used to analyze the differences of KAI1 mRNA and protein expression among the three groups., Results: The stably transfected cell lines of Y79-KAI1 and Y79-KAI1/zero were established. The result of fluorescent quantitative real-time PCR showed that the relative quantification of mRNA level of KAI1 gene in the three kinds of cells above was 183.67 ± 21.20, 1.42 ± 0.55, 1.00 ± 0.00, respectively. And the expression level of KAI1 mRNA in Y79-KAI1 cells was significantly higher than those in Y79-KAI1/zero and Y79 cells (F = 108.74, P = 0.000). The results of Western blot showed that the expression level of the KAI1 protein in Y79-KAI1 cells was significantly higher than those in Y79-KAI1/zero and Y79 cells (F = 34.36, P = 0.001). Immunofluorescent staining showed that Y79 and Y79-KAI1/zero cells had no detectable KAI1 expression, while Y79-KAI1 cells expressed KAI1 in the cytoplasm surrounding the nuclei. Among the 84 tumor metastasis-related genes examined, 7 genes were up-regulated more than 2 folds and 6 genes were down-regulated over 50%., Conclusion: Over-expression of KAI1 may result in differential expression of tumor metastasis-related genes in Y79 cells, which may be related to the inhibitory effect on the tumor metastasis of retinoblastoma.
- Published
- 2012
26. RACK1 suppresses gastric tumorigenesis by stabilizing the β-catenin destruction complex.
- Author
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Deng YZ, Yao F, Li JJ, Mao ZF, Hu PT, Long LY, Li G, Ji XD, Shi S, Guan DX, Feng YY, Cui L, Li DS, Liu Y, Du X, Guo MZ, Xu LY, Li EM, Wang HY, and Xie D
- Subjects
- Adaptor Proteins, Signal Transducing metabolism, Animals, Axin Signaling Complex genetics, Case-Control Studies, Cell Differentiation, Cell Line, Tumor, Cell Proliferation, Dishevelled Proteins, Female, GTP-Binding Proteins genetics, Gene Expression Regulation, Neoplastic, Glycogen Synthase Kinase 3 metabolism, Glycogen Synthase Kinase 3 beta, HEK293 Cells, Humans, Immunohistochemistry, Male, Mice, Mice, Nude, Middle Aged, Neoplasm Invasiveness, Neoplasm Proteins genetics, Neoplasm Transplantation, Phosphoproteins metabolism, RNA Interference, Receptors for Activated C Kinase, Receptors, Cell Surface genetics, Stomach Neoplasms genetics, Stomach Neoplasms pathology, Stomach Neoplasms prevention & control, Time Factors, Transfection, Tumor Suppressor Proteins genetics, Wnt3A Protein metabolism, Zebrafish embryology, Zebrafish genetics, Zebrafish Proteins genetics, Zebrafish Proteins metabolism, beta Catenin metabolism, Axin Signaling Complex metabolism, GTP-Binding Proteins metabolism, Neoplasm Proteins metabolism, Receptors, Cell Surface metabolism, Stomach Neoplasms metabolism, Tumor Suppressor Proteins metabolism, Wnt Signaling Pathway genetics
- Abstract
Background & Aims: Dysregulation of Wnt signaling has been involved in gastric tumorigenesis by mechanisms that are not fully understood. The receptor for activated protein kinase C (RACK1, GNB2L1) is involved in development of different tumor types, but its expression and function have not been investigated in gastric tumors., Methods: We analyzed expression of RACK1 in gastric tumor samples and their matched normal tissues from 116 patients using immunohistochemistry. Effects of knockdown with small interfering RNAs or overexpression of RACK1 in gastric cancer cell lines were evaluated in cell growth and tumor xenograft. RACK1 signaling pathways were investigated in cells and zebrafish embryos using immunoblot, immunoprecipitation, microinjection, and in situ hybridization assays., Results: Expression of RACK1 was reduced in gastric tumor samples and correlated with depth of tumor infiltration and poor differentiation. Knockdown of RACK1 in gastric cancer cells accelerated their anchorage-independent proliferation in soft agar, whereas overexpression of RACK1 reduced their tumorigenicity in nude mice. RACK1 formed a complex with glycogen synthase kinase Gsk3β and Axin to promote the interaction between Gsk3β and β-catenin and thereby stabilized the β-catenin destruction complex. On stimulation of Wnt3a, RACK1 repressed Wnt signaling by inhibiting recruitment of Axin by Dishevelled 2 (Dvl2). Moreover, there was an inverse correlation between expression of RACK1 and localization of β-catenin to the cytoplasm/nucleus in human gastric tumor samples., Conclusions: RACK1 negatively regulates Wnt signaling pathway by stabilizing the β-catenin destruction complex and act as a tumor suppressor in gastric cancer cells., (Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.)
- Published
- 2012
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27. RACK1 promotes non-small-cell lung cancer tumorigenicity through activating sonic hedgehog signaling pathway.
- Author
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Shi S, Deng YZ, Zhao JS, Ji XD, Shi J, Feng YX, Li G, Li JJ, Zhu D, Koeffler HP, Zhao Y, and Xie D
- Subjects
- Animals, Carcinoma, Non-Small-Cell Lung diagnosis, Carcinoma, Non-Small-Cell Lung pathology, Carcinoma, Non-Small-Cell Lung therapy, Humans, Lung Neoplasms diagnosis, Lung Neoplasms pathology, Lung Neoplasms therapy, Male, Mice, Mice, Nude, Neoplasm Metastasis, Neoplasm Transplantation, Receptors for Activated C Kinase, Receptors, G-Protein-Coupled metabolism, Smoothened Receptor, Transcription Factors metabolism, Transcription, Genetic, Transplantation, Heterologous, Zinc Finger Protein GLI1, Biomarkers, Tumor metabolism, Carcinoma, Non-Small-Cell Lung metabolism, GTP-Binding Proteins metabolism, Hedgehog Proteins metabolism, Lung Neoplasms metabolism, Neoplasm Proteins metabolism, Receptors, Cell Surface metabolism, Signal Transduction
- Abstract
Non-small-cell lung cancer (NSCLC) is a deadly disease due to lack of effective diagnosis biomarker and therapeutic target. Much effort has been made in defining gene defects in NSCLC, but its full molecular pathogenesis remains unexplored. Here, we found RACK1 (receptor of activated kinase 1) was elevated in most NSCLC, and its expression level correlated with key pathological characteristics including tumor differentiation, stage, and metastasis. In addition, RACK1 activated sonic hedgehog signaling pathway by interacting with and activating Smoothened to mediate Gli1-dependent transcription in NSCLC cells. And silencing RACK1 dramatically inhibited in vivo tumor growth and metastasis by blocking the sonic hedgehog signaling pathway. These results suggest that RACK1 represents a new promising diagnosis biomarker and therapeutic target for NSCLC.
- Published
- 2012
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28. EphB3 suppresses non-small-cell lung cancer metastasis via a PP2A/RACK1/Akt signalling complex.
- Author
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Li G, Ji XD, Gao H, Zhao JS, Xu JF, Sun ZJ, Deng YZ, Shi S, Feng YX, Zhu YQ, Wang T, Li JJ, and Xie D
- Subjects
- Animals, Carcinoma, Non-Small-Cell Lung pathology, Cell Movement, HEK293 Cells, Humans, Ligands, Lung Neoplasms pathology, Mice, Mice, Nude, Models, Biological, Mutation, Neoplasm Metastasis, Neoplasm Transplantation, Phosphorylation, Photons, Receptors for Activated C Kinase, Signal Transduction, Tyrosine chemistry, Carcinoma, Non-Small-Cell Lung metabolism, GTP-Binding Proteins metabolism, Gene Expression Regulation, Neoplastic, Lung Neoplasms metabolism, Neoplasm Proteins metabolism, Neuropeptides metabolism, Proto-Oncogene Proteins c-akt metabolism, Receptor, EphB3 metabolism, Receptors, Cell Surface metabolism
- Abstract
Eph receptors are implicated in regulating the malignant progression of cancer. Here we find that despite overexpression of EphB3 in human non-small-cell lung cancer, as reported previously, the expression of its cognate ligands, either ephrin-B1 or ephrin-B2, is significantly downregulated, leading to reduced tyrosine phosphorylation of EphB3. Forced activation of EphB3 kinase in EphB3-overexpressing non-small-cell lung cancer cells inhibits cell migratory capability in vitro as well as metastatic seeding in vivo. Furthermore, we identify a novel EphB3-binding protein, the receptor for activated C-kinase 1, which mediates the assembly of a ternary signal complex comprising protein phosphatase 2A, Akt and itself in response to EphB3 activation, leading to reduced Akt phosphorylation and subsequent inhibition of cell migration. Our study reveals a novel tumour-suppressive signalling pathway associated with kinase-activated EphB3 in non-small-cell lung cancer, and provides a potential therapeutic strategy by activating EphB3 signalling, thus inhibiting tumour metastasis.
- Published
- 2012
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29. EphB3 is overexpressed in non-small-cell lung cancer and promotes tumor metastasis by enhancing cell survival and migration.
- Author
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Ji XD, Li G, Feng YX, Zhao JS, Li JJ, Sun ZJ, Shi S, Deng YZ, Xu JF, Zhu YQ, Koeffler HP, Tong XJ, and Xie D
- Subjects
- Animals, Apoptosis physiology, Carcinoma, Non-Small-Cell Lung genetics, Carcinoma, Non-Small-Cell Lung pathology, Caspase 8 metabolism, Cell Adhesion physiology, Cell Growth Processes physiology, Cell Line, Tumor, Cell Movement physiology, Cell Survival physiology, Cell Transformation, Neoplastic genetics, Cell Transformation, Neoplastic metabolism, Cell Transformation, Neoplastic pathology, DNA, Neoplasm biosynthesis, DNA, Neoplasm genetics, Disease Progression, Gene Knockdown Techniques, Humans, Lung Neoplasms genetics, Lung Neoplasms pathology, Male, Mice, Mice, Nude, Neoplasm Metastasis, RNA, Messenger genetics, RNA, Messenger metabolism, Receptor, EphB3 genetics, Carcinoma, Non-Small-Cell Lung enzymology, Lung Neoplasms enzymology, Receptor, EphB3 biosynthesis
- Abstract
Eph receptors, the largest subfamily of transmembrane tyrosine kinase receptors, have been increasingly implicated in various physiologic and pathologic processes, and the roles of the Eph family members during tumorigenesis have recently attracted growing attention. Until now, research on EphB3 function in cancer is limited to focusing on tumor suppression by EphB receptors in colorectal cancer. However, its function in other types of cancer remains poorly investigated. In this study, we explored the function of EphB3 in non-small-cell lung cancer (NSCLC). We found that the expression of EphB3 was significantly upregulated in clinical samples and cell lines, and the expression level correlated with the patient pathologic characteristics, including tumor size, differentiation, and metastasis. Overexpression of EphB3 in NSCLC cell lines accelerated cell growth and migration and promoted tumorigenicity in xenografts in a kinase-independent manner. In contrast, downregulation of EphB3 inhibited cell proliferation and migration and suppressed in vivo tumor growth and metastasis. Furthermore, we showed that silencing of EphB3 inhibited cell growth by reducing DNA synthesis and caspase-8-mediated apoptosis and suppressed cell migration by increasing accumulation of focal adhesion formation. Taken together, our findings suggest that EphB3 provides critical support to the development and progression of NSCLC by stimulating cell growth, migration, and survival, thereby implicating EphB3 as a potential therapeutic target in NSCLC.
- Published
- 2011
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30. Tumor initiating cells in esophageal squamous cell carcinomas express high levels of CD44.
- Author
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Zhao JS, Li WJ, Ge D, Zhang PJ, Li JJ, Lu CL, Ji XD, Guan DX, Gao H, Xu LY, Li EM, Soukiasian H, Koeffler HP, Wang XF, and Xie D
- Subjects
- Adult, Animals, Antineoplastic Agents pharmacology, Antineoplastic Agents therapeutic use, Carcinoma, Squamous Cell drug therapy, Cell Death drug effects, Cell Differentiation drug effects, Cell Line, Tumor, Down-Regulation drug effects, Esophageal Neoplasms drug therapy, Female, Humans, Male, Mice, Middle Aged, Neoplastic Stem Cells drug effects, Carcinoma, Squamous Cell pathology, Esophageal Neoplasms pathology, Hyaluronan Receptors metabolism, Neoplastic Stem Cells pathology
- Abstract
Background: Esophageal Squamous Cell Carcinoma (ESCC) is a major subtype of esophageal cancer causing significant morbility and mortality in Asia. Mechanism of initiation and progression of this disease is unclear. Tumor initiating cells (TICs) are the subpopulation of cells which have the ability to self-renew, as well as, to drive initiation and progression of cancer. Increasing evidence has shown that TICs exist in a variety of tumors. However, the identification and characterization of TICs in esophageal carcinoma has remained elusive., Methodology/principal Findings: to identify TICs in ESCC, ESCC cell lines including two primary cells were used for screening suitable surface marker. Then colony formation assay, drug resistant assay and tumorigenicity assay in immune deficient mice were used to characterize TICs in ESCC. We found that just the CD44 expression correlated with tumorigenicity in ESCC cell lines. And then induced differentiation of ESCC cells by all-trans retinoic acid treatment led to decreased expression of CD44. The FACS isolated cell subpopulations with high CD44 expression showed increased colony formation and drug resistance in vitro, as well as significantly enhanced tumorigenicity in NOD/SICD mice, as compared to the low expressing CD44 ESCC cells., Conclusions/significance: our study has discovered a novel TIC surface marker, CD44, which can be utilized to enrich efficiently the TICs in ESCC. These findings will be useful for further studies of these cells and exploring therapeutic approaches.
- Published
- 2011
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31. Overexpression of degenerative spermatocyte homolog 1 up-regulates the expression of cyclin D1 and enhances metastatic efficiency in esophageal carcinoma Eca109 cells.
- Author
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Zhou W, Ye XL, Sun ZJ, Ji XD, Chen HX, and Xie D
- Subjects
- Animals, Blotting, Western, Cadherins genetics, Cadherins metabolism, Cell Cycle, Cell Movement, Cell Proliferation, Cyclin D1 metabolism, Esophageal Neoplasms metabolism, Fluorescent Antibody Technique, Gene Silencing drug effects, Humans, Luciferases metabolism, Mice, Mice, Nude, NF-kappa B genetics, NF-kappa B metabolism, Neoplasm Metastasis, RNA, Messenger genetics, RNA, Messenger metabolism, RNA, Small Interfering pharmacology, Reverse Transcriptase Polymerase Chain Reaction, Transfection, Tumor Cells, Cultured, Up-Regulation, Cyclin D1 genetics, Esophageal Neoplasms pathology, Fatty Acid Desaturases genetics, Gene Expression Regulation, Neoplastic physiology
- Abstract
Cyclin D1 plays a pivotal role in cell-cycle transition through G1 phase. In this article, we found that Degenerative Spermatocyte Homolog 1 (DEGS1) up-regulated the expression of cyclin D1 and the activation of transcription factor NF-kappaB was essential for DEGS1-induced cyclin D1 production. Forced expression of DEGS1 in Esophageal carcinoma cell line Eca109 cells increased their ability of cell migration and significantly induced tumor metastasis in nude mice, whereas RNA interference-mediated knockdown of DEGS1 cells significantly inhibited cell migration in vitro, as well as tumor metastasis in vivo. Our results demonstrated that expression of DEGS1 up-regulated the expression of cyclin D1 and enhanced the efficiency of tumor metastasis., ((c) 2009 Wiley-Liss, Inc.)
- Published
- 2009
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32. De novo biosynthetic profiling of high abundance proteins in cystic fibrosis lung epithelial cells.
- Author
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Pollard HB, Eidelman O, Jozwik C, Huang W, Srivastava M, Ji XD, McGowan B, Norris CF, Todo T, Darling T, Mogayzel PJ, Zeitlin PL, Wright J, Guggino WB, Metcalf E, Driscoll WJ, Mueller G, Paweletz C, and Jacobowitz DM
- Subjects
- Cell Line, Electrophoresis, Gel, Two-Dimensional, Humans, Methionine metabolism, Peptide Mapping, Silver Staining, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Sulfur Radioisotopes, Cystic Fibrosis metabolism, Epithelial Cells metabolism, Lung metabolism, Proteome analysis
- Abstract
In previous studies with cystic fibrosis (CF) IB3-1 lung epithelial cells in culture, we identified 194 unique high abundance proteins by conventional two-dimensional gel electrophoresis and mass spectrometry (Pollard, H. B., Ji, X.-D., Jozwik, C. J., and Jacobowitz, D. M. (2005) High abundance protein profiling of cystic fibrosis lung epithelial cells. Proteomics 5, 2210-2226). In the present work we compared the IB3-1 cells with IB3-1/S9 daughter cells repaired by gene transfer with AAV-(wild type)CFTR. We report that gene transfer resulted in significant changes in silver stain intensity of only 20 of the 194 proteins. However, simultaneous measurement of de novo biosynthetic rates with [(35)S]methionine of all 194 proteins in both cell types resulted in the identification of an additional 31 CF-specific proteins. Of the 51 proteins identified by this hybrid approach, only six proteins changed similarly in both the mass and kinetics categories. This kinetic portion of the high abundance CF proteome, hidden from direct analysis of abundance, included proteins from transcription and signaling pathways such as NFkappaB, chaperones such as HSC70, cytoskeletal proteins, and others. Connectivity analysis indicated that approximately 30% of the 51-member hybrid high abundance CF proteome interacts with the NFkappaB signaling pathway. In conclusion, measurement of biosynthetic rates on a global scale can be used to identify disease-specific differences within the high abundance cystic fibrosis proteome. Most of these kinetically defined proteins are unaffected in expression level when using conventional silver stain analysis. We anticipate that this novel hybrid approach to discovery of the high abundance CF proteome will find general application to other proteomic problems in biology and medicine.
- Published
- 2006
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33. Expression of soluble, biologically active recombinant human endostatin in Escherichia coli.
- Author
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Xu HM, Zhang GY, Ji XD, Cao L, Shu L, and Hua ZC
- Subjects
- 3T3 Cells, Angiogenesis Inhibitors genetics, Animals, Biological Assay, Capillaries cytology, Capillaries drug effects, Cattle, Cell Proliferation drug effects, Chick Embryo, Endostatins genetics, Endothelial Cells drug effects, Gene Expression Regulation, Bacterial, Humans, Mice, Molecular Chaperones metabolism, Recombinant Proteins biosynthesis, Recombinant Proteins genetics, Recombinant Proteins pharmacology, Temperature, Angiogenesis Inhibitors biosynthesis, Angiogenesis Inhibitors pharmacology, Endostatins biosynthesis, Endostatins pharmacology, Escherichia coli genetics
- Abstract
Endostatin, a 20kDa C-terminal fragment of collagen XVIII, is a potent anti-angiogenic protein and inhibitor of tumor growth. Recombinant endostatin was prepared from Escherichia coli deposited as insoluble, inactive inclusion bodies. In the present study, we produced soluble and biologically active recombinant human endostatin (rhEndostatin) in E. coli by employing both co-expression of the molecular chaperones and lower temperature fermentation. Two groups of chaperones Trigger factor and GroEL-GroES (GroEL/ES), DnaK-DnaJ-GrpE and GroEL/ES, were co-expressed, respectively, with rhEndostatin at different temperatures (37, 25, and 16 degrees C). It revealed that low temperature or molecular chaperones alone could enhance the production of active rhEndostatin; meanwhile, combinational employment of low temperature cultivation (16 degrees C) together with co-expression of DnaK-DnaJ-GrpE and GroEL/ES was more effective to prevent aggregation of rhEndostatin. The production of soluble rhEndostatin was about 36 mg/L, and at least 16 mg of rhEndostatin was purified from 1L flask culture. The purified rhEndostatin specifically inhibited the proliferation of endothelial cell-bovine capillary endothelial cell in a dose-dependent manner, and it showed potent anti-angiogenic capability on the chorioallantoic membrane of chick embryo in vivo. Our study provides a feasible and convenient approach to produce soluble and biologically active rhEndostatin.
- Published
- 2005
- Full Text
- View/download PDF
34. High abundance protein profiling of cystic fibrosis lung epithelial cells.
- Author
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Pollard HB, Ji XD, Jozwik C, and Jacobowitz DM
- Subjects
- Cell Culture Techniques, Cell Line, Cystic Fibrosis genetics, Electrophoresis, Gel, Two-Dimensional, Humans, Image Processing, Computer-Assisted, Isoelectric Point, Mass Spectrometry, Peptides chemistry, Proteins drug effects, Proteins isolation & purification, Silver Staining, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Trypsin pharmacology, Cystic Fibrosis pathology, Epithelial Cells chemistry, Lung pathology, Peptide Mapping, Proteins chemistry
- Abstract
Protein profiles of cultured cystic fibrosis (CF) lung epithelial cells were analyzed by two-dimensional gel electrophoresis and mass spectrometry (MS). The analysis gave rise to a protein map over the pI range of 4-7, and a molecular weight range of ca. 100-10 kDa. The map contains 194 identified proteins, which were detectable by silver stain. All silver stained features were identified by matrix-assisted laser desorption/ionization-time of flight MS of tryptic peptides. Some proteins were found to be represented by multiple features on the 2-D gel. Among the high abundance proteins identified were sets of proteins associated with inflammation, including the classical NFkappaB, p65 (RelA) and NFkappaB, p65 (RelB). We suggest that this composite atlas of the high abundance CF lung epithelial proteome will serve as a reference database for future studies of candidate CF drugs, validating different approaches to CFTR gene therapy, and analogous investigations of other types of human lung disorders.
- Published
- 2005
- Full Text
- View/download PDF
35. [The advances of thalidomide in oral mucosal uses].
- Author
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Shi J, Ji XD, and Chen QM
- Subjects
- Humans, Mouth Mucosa pathology, Mouth Diseases drug therapy, Thalidomide therapeutic use
- Published
- 2004
36. Agonist-independent nuclear localization of the Apelin, angiotensin AT1, and bradykinin B2 receptors.
- Author
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Lee DK, Lança AJ, Cheng R, Nguyen T, Ji XD, Gobeil F Jr, Chemtob S, George SR, and O'Dowd BF
- Subjects
- Animals, Apelin Receptors, Brain ultrastructure, COS Cells, Cell Fractionation, Cell Line, Cerebellum ultrastructure, Chlorocebus aethiops, Cytoplasm chemistry, Embryo, Mammalian, Gene Expression, Green Fluorescent Proteins, Humans, Hypothalamus ultrastructure, Immunohistochemistry, Kidney, Luminescent Proteins genetics, Microscopy, Confocal, Neurons ultrastructure, Protein Sorting Signals, Rats, Receptor, Angiotensin, Type 1 genetics, Receptor, Bradykinin B2 genetics, Receptors, G-Protein-Coupled genetics, Recombinant Fusion Proteins, Signal Transduction, Transfection, Cell Nucleus chemistry, Receptor, Angiotensin, Type 1 analysis, Receptor, Bradykinin B2 analysis, Receptors, G-Protein-Coupled analysis
- Abstract
Signaling of the apelin, angiotensin, and bradykinin peptides is mediated by G protein-coupled receptors related through structure and similarities of physiological function. We report nuclear expression as a characteristic of these receptors, including a nuclear localization for the apelin receptor in brain and cerebellum-derived D283 Med cells and the AT(1) and bradykinin B(2) receptors in HEK-293T cells. Immunocytochemical analyses revealed the apelin receptor with localization in neuronal nuclei in cerebellum and hypothalamus, exhibiting expression in neuronal cytoplasm or in both nuclei and cytoplasm. Confocal microscopy of HEK-293T cells revealed the majority of transfected cells displayed constitutive nuclear localization of AT(1) and B(2) receptors, whereas apelin receptors did not show nuclear localization in these cells. The majority of apelin receptor-transfected cerebellum D283 Med cells showed receptor nuclear expression. Immunoblot analyses of subcellular-fractionated D283 Med cells demonstrated endogenous apelin receptor species in nuclear fractions. In addition, an identified nuclear localization signal motif in the third intracellular loop of the apelin receptor was disrupted by a substituted glutamine in place of lysine. This apelin receptor (K242Q) did not exhibit nuclear localization in D283 Med cells. These results demonstrate the following: (i) the apelin receptor exhibits nuclear localization in human brain; (ii) distinct cell-dependent mechanisms for the nuclear transport of apelin, AT(1), and B(2) receptors; and (iii) the disruption of a nuclear localization signal sequence disrupts the nuclear translocation of the apelin receptor. This discovery of apelin, AT(1), and B(2) receptors with agonist-independent nuclear translocation suggests major unanticipated roles for these receptors in cell signaling and function.
- Published
- 2004
- Full Text
- View/download PDF
37. 2-Substitution of adenine nucleotide analogues containing a bicyclo[3.1.0]hexane ring system locked in a northern conformation: enhanced potency as P2Y1 receptor antagonists.
- Author
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Kim HS, Ohno M, Xu B, Kim HO, Choi Y, Ji XD, Maddileti S, Marquez VE, Harden TK, and Jacobson KA
- Subjects
- Adenine Nucleotides chemistry, Adenine Nucleotides pharmacology, Adenosine Diphosphate analogs & derivatives, Adenosine Diphosphate chemistry, Adenosine Diphosphate pharmacology, Binding, Competitive, Cell Line, Cell Line, Tumor, Humans, Molecular Conformation, Radioligand Assay, Receptors, Purinergic P2 metabolism, Receptors, Purinergic P2Y1, Recombinant Proteins antagonists & inhibitors, Recombinant Proteins metabolism, Stereoisomerism, Structure-Activity Relationship, Adenine Nucleotides chemical synthesis, Adenosine Diphosphate chemical synthesis, Purinergic P2 Receptor Antagonists
- Abstract
Preference for the northern (N) ring conformation of the ribose moiety of adenine nucleotide 3',5'-bisphosphate antagonists of P2Y(1) receptors was established by using a ring-constrained methanocarba (a bicyclo[3.1.0]hexane) ring as a ribose substitute (Nandanan et al. J. Med. Chem. 2000, 43, 829-842). We have now combined the ring-constrained (N)-methanocarba modification with other functionalities at the 2-position of the adenine moiety. A new synthetic route to this series of bisphosphate derivatives was introduced, consisting of phosphorylation of the pseudoribose moiety prior to coupling with the adenine base. The activity of the newly synthesized analogues was determined by measuring antagonism of 2-methylthio-ADP-stimulated phospholipase C (PLC) activity in 1321N1 human astrocytoma cells expressing the recombinant human P2Y(1) receptor and by using the radiolabeled antagonist [(3)H]2-chloro-N(6)-methyl-(N)-methanocarba-2'-deoxyadenosine 3',5'-bisphosphate 5 in a newly developed binding assay in Sf9 cell membranes. Within the series of 2-halo analogues, the most potent molecule at the hP2Y(1) receptor was an (N)-methanocarba N(6)-methyl-2-iodo analogue 12, which displayed a K(i) value in competition for binding of [(3)H]5 of 0.79 nM and a K(B) value of 1.74 nM for inhibition of PLC. Thus, 12 is the most potent antagonist selective for the P2Y(1) receptor yet reported. The 2-iodo group was substituted with trimethyltin, thus providing a parallel synthetic route for the introduction of an iodo group in this high-affinity antagonist. The (N)-methanocarba-2-methylthio, 2-methylseleno, 2-hexyl, 2-(1-hexenyl), and 2-(1-hexynyl) analogues bound less well, exhibiting micromolar affinity at P2Y(1) receptors. An enzymatic method of synthesis of the 3',5'-bisphosphate from the corresponding 3'-monophosphate, suitable for the preparation of a radiophosphorylated analogue, was explored.
- Published
- 2003
- Full Text
- View/download PDF
38. Quinazolines as adenosine receptor antagonists: SAR and selectivity for A2B receptors.
- Author
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Webb TR, Lvovskiy D, Kim SA, Ji Xd, Melman N, Linden J, and Jacobson KA
- Subjects
- Animals, Brain metabolism, Cell Line, Cell Membrane metabolism, Corpus Striatum metabolism, Databases, Factual, Humans, Radioligand Assay, Rats, Receptor, Adenosine A2B, Structure-Activity Relationship, Substrate Specificity, Tritium, Purinergic P1 Receptor Antagonists, Quinazolines chemistry, Quinazolines pharmacology
- Abstract
We have recently reported the discovery of numerous new compounds that are selective inhibitors of all of the subtypes of the adenosine receptor family via a pharmacophore database searching and screening strategy. During the course of this work we made the unexpected discovery of a potent A(2B) receptor antagonist, 4-methyl-7-methoxyquinazolyl-2-(2'-amino-4'-imidazolinone) (38, CMB 6446), which showed selectivity for this receptor and functioned as an antagonist, with a binding K(i) value of 112 nM. We explored the effects of both substituent- and ring-structural variations on the receptor affinity in this series of derivatives, which were found to be mostly non-selective adenosine receptor ligands with K(i) values in the micromolar range. Since no enhancement of A(2B) receptor affinity of 38 was achieved, the previously reported pharmacophore-based searching strategy yielded the most potent and selective structurally-related hit in the database originally searched.
- Published
- 2003
- Full Text
- View/download PDF
39. Quantitation of the P2Y(1) receptor with a high affinity radiolabeled antagonist.
- Author
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Waldo GL, Corbitt J, Boyer JL, Ravi G, Kim HS, Ji XD, Lacy J, Jacobson KA, and Harden TK
- Subjects
- Adenosine Diphosphate chemical synthesis, Adenosine Diphosphate chemistry, Animals, Cells, Cultured, Female, Humans, Insecta cytology, Purinergic P2 Receptor Antagonists, Radiopharmaceuticals chemical synthesis, Radiopharmaceuticals chemistry, Rats, Rats, Sprague-Dawley, Receptors, Purinergic P2Y1, Tritium, Adenosine Diphosphate analogs & derivatives, Adenosine Diphosphate pharmacology, Radiopharmaceuticals pharmacology, Receptors, Purinergic P2 analysis
- Abstract
2-Chloro-N(6)-methyl-(N )-methanocarba-2'-deoxyadenosine-3',5'- bisphosphate (MRS2279) was developed previously as a selective high-affinity, non-nucleotide P2Y(1) receptor (P2Y1-R) antagonist (J Med Chem 43:829-842, 2002; Br J Pharmacol 135:2004-2010, 2002). We have taken advantage of the N(6)-methyl substitution in the adenine base to incorporate [(3)H]methylamine into the synthesis of [(3)H]MRS2279 to high (89 Ci/mmol) specific radioactivity and have used this molecule as a radioligand for the P2Y1-R. [(3)H]MRS2279 bound to membranes from Sf9 insect cells expressing recombinant human P2Y1-R but not to membranes from wild-type Sf9 cells or Sf9 cells expressing high levels of recombinant P2Y(2) or P2Y(12) receptors. Equilibrium binding of [(3)H]MRS2279 to P2Y1-R expressed in Sf9 membranes was with a high affinity (K(d) = 8 nM) essentially identical to the apparent affinity of MRS2279 determined previously in studies of P2Y1-R-promoted inositol phosphate accumulation or platelet aggregation. A kinetically derived K(d) calculated from independent determinations of the rate constants of association (7.15 x 10(7) M(-1) min(-1)) and dissociation (0.72 min(-1)) of [(3)H]MRS2279 also was in good agreement with the K(d) derived from equilibrium binding studies. Competition binding assays with [(3)H]MRS2279 and P2Y1-R expressing Sf9 cell membranes revealed K(i) values for the P2Y1-R antagonists MRS2279 (K(i) = 13 nM), N(6)-methyl-2'-deoxyadenosine-3',5'-bisphosphate (MRS2179; K(i) = 84 nM), adenosine-3', 5'-bisphosphate (K(i)=900 nM), and pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (K(i) = 6 microM) that were in good agreement with antagonist activities of these molecules previously determined at the P2Y1-R in intact tissues. Moreover, [(3)H]MRS2279 also bound with high affinity (K(d) = 4-8 nM) to Chinese hamster ovary (CHO) or 1321N1 human astrocytoma cells stably expressing the human P2Y1-R, but specific binding was not observed in wild-type CHO or 1321N1 cells. [(3)H]MRS2279 bound with high affinity (K(d) = 16 nM) to a binding site on out-dated human platelets (5-35 receptors/platelet) and rat brain membranes (210 fmol/mg protein) that fit the expected drug selectivity of a P2Y1-R. Taken together, these results indicate that [(3)H]MRS2279 is the first broadly applicable antagonist radioligand for a P2Y receptor.
- Published
- 2002
- Full Text
- View/download PDF
40. Interactions of flavones and other phytochemicals with adenosine receptors.
- Author
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Jacobson KA, Moro S, Manthey JA, West PL, and Ji XD
- Subjects
- Animals, Computer Simulation, Diet, Drug Design, Drug Evaluation, Preclinical, Flavonoids chemical synthesis, Flavonoids chemistry, Flavonoids metabolism, Humans, Hydrogen Bonding, Hydrophobic and Hydrophilic Interactions, Isoflavones chemistry, Isoflavones pharmacology, Methylation, Models, Molecular, Molecular Structure, Rats, Receptors, Purinergic P1 metabolism, Structure-Activity Relationship, Flavonoids pharmacology, Purinergic P1 Receptor Antagonists
- Abstract
Dietary flavonoids have varied effects on animal cells, such as inhibition of platelet binding and aggregation, inhibition of inflammation, and anticancer properties, but the mechanisms of these effects remain largely unexplained. Adenosine receptors are involved in the homeostasis of the immune, cardiovascular, and central nervous systems, and adenosine agonists/antagonists exert many similar effects. The affinity of flavonoids and other phytochemicals to adenosine receptors suggests that a wide range of natural substances in the diet may potentially block the effects of endogenous adenosine. We used competitive radioligand binding assays to screen flavonoid libraries for affinity and a computational CoMFA analysis of flavonoids to compare steric and electrostatic requirements for ligand recognition at three subtypes of adenosine receptors. Flavone derivatives, such as galangin, were found to bind to three subtypes of adenosine receptors in the microM range. Pentamethylmorin (Ki 2.65 microM) was 14- to 17-fold selective for human A3 receptors than for A1 and A2A receptors. An isoflavone, genistein, was found to bind to A1 receptors. Aurones, such as hispidol (Ki 350 nM) are selective A1 receptor antagonists, and, like genistein, are present in soy. The flavones, chemically optimized for receptor binding, have led to the antagonist, MRS 1067 (3,6-dichloro-2'-(isopropoxy)4'-methylflavone), which is 200-fold more selective for human A3 than A1 receptors. Adenosine receptor antagonism, therefore, may be important in the spectrum of biological activities reported for the flavonoids.
- Published
- 2002
- Full Text
- View/download PDF
41. Growth suppression of intracranial xenografted glioblastomas overexpressing mutant epidermal growth factor receptors by systemic administration of monoclonal antibody (mAb) 806, a novel monoclonal antibody directed to the receptor.
- Author
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Mishima K, Johns TG, Luwor RB, Scott AM, Stockert E, Jungbluth AA, Ji XD, Suvarna P, Voland JR, Old LJ, Huang HJ, and Cavenee WK
- Subjects
- Animals, Apoptosis drug effects, Blotting, Western, Brain Neoplasms genetics, Brain Neoplasms mortality, Cell Division drug effects, Down-Regulation drug effects, ErbB Receptors immunology, ErbB Receptors metabolism, Gene Expression Regulation, Neoplastic, Glioblastoma genetics, Glioblastoma mortality, Humans, In Situ Nick-End Labeling, Mice, Mice, Nude, Mutation, Neovascularization, Pathologic prevention & control, Phosphorylation drug effects, Proto-Oncogene Proteins c-bcl-2 drug effects, Proto-Oncogene Proteins c-bcl-2 metabolism, Survival Analysis, Survival Rate, Transplantation, Heterologous, Treatment Outcome, Tumor Cells, Cultured, Xenograft Model Antitumor Assays, bcl-X Protein, Antibodies, Monoclonal pharmacology, Antineoplastic Agents pharmacology, Brain Neoplasms drug therapy, ErbB Receptors genetics, Glioblastoma drug therapy
- Abstract
A mutant epidermal growth factor receptor (variously called DeltaEGFR, de2-7 EGFR, or EGFRvIII) containing a deletion of 267 amino acids of the extracellular domain is frequently highly expressed in human malignant gliomas and has been reported for cancers of the lung, breast, and prostate. We tested the efficacy of a novel monoclonal anti-DeltaEGFR antibody, mAb 806, on the growth of intracranial xenografted gliomas in nude mice. Systemic treatment with mAb 806 significantly reduced the volume of tumors and increased the survival of mice bearing xenografts of U87 MG.DeltaEGFR, LN-Z308.DeltaEGFR, or A1207.DeltaEGFR gliomas, each of which expresses high levels of DeltaEGFR. In contrast, mAb 806 treatment was ineffective with mice bearing the parental U87 MG tumors, which expressed low levels of endogenous wild-type EGFR, or U87 MG.DK tumors, which expressed high levels of kinase-deficient DeltaEGFR. A slight increase of survival of mice xenografted with a wild-type EGFR-overexpressing U87 MG glioma (U87 MG.wtEGFR) was effected by mAb 806 concordant with its weak cross-reactivity with such cells. Treatment of U87 MG.DeltaEGFR tumors in mice with mAb 806 caused decreases in both tumor growth and angiogenesis, as well as increased apoptosis. Mechanistically, in vivo mAb 806 treatment resulted in reduced phosphorylation of the constitutively active DeltaEGFR and caused down-regulated expression of the apoptotic protector, Bcl-XL. These data provide preclinical evidence that mAb 806 treatment may be a useful biotherapeutic agent for those aggressive gliomas that express DeltaEGFR.
- Published
- 2001
42. Ring-Constrained (N)-methanocarba nucleosides as adenosine receptor agonists: independent 5'-uronamide and 2'-deoxy modifications.
- Author
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Lee K, Ravi G, Ji XD, Marquez VE, and Jacobson KA
- Subjects
- Adenine metabolism, Adenine pharmacology, Adenosine metabolism, Adenosine pharmacology, Animals, Binding, Competitive, Brain ultrastructure, CHO Cells, Cell Line, Cell Membrane chemistry, Cricetinae, Cyclopentanes metabolism, Cyclopentanes pharmacology, Humans, Protein Binding, Rats, Receptors, Purinergic P1 metabolism, Structure-Activity Relationship, Transfection, Adenine analogs & derivatives, Adenine chemical synthesis, Adenosine analogs & derivatives, Adenosine chemical synthesis, Cyclopentanes chemical synthesis, Nucleosides pharmacology, Purinergic P1 Receptor Agonists
- Abstract
Novel methanocarba adenosine analogues, having the pseudo-ribose northern (N) conformation preferred at adenosine receptors (ARs), were synthesized and tested in binding assays. The 5'-uronamide modification preserved [N6-(3-iodobenzyl)] or enhanced (N6-methyl) affinity at A3ARs, while the 2'-deoxy modification reduced affinity and efficacy in a functional assay.
- Published
- 2001
- Full Text
- View/download PDF
43. Ribose modified nucleosides and nucleotides as ligands for purine receptors.
- Author
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Jacobson KA, Ravi RG, Nandanan E, Kim HS, Moro S, Kim YC, Lee K, Barak D, Marquez VE, and Ji XD
- Subjects
- Animals, Drug Design, Humans, Ligands, Nucleosides pharmacology, Nucleotides pharmacology, Purinergic P1 Receptor Agonists, Purinergic P1 Receptor Antagonists, Purinergic P2 Receptor Agonists, Purinergic P2 Receptor Antagonists, Rats, Receptors, Purinergic P1 chemistry, Receptors, Purinergic P2 chemistry, Receptors, Purinergic P2Y1, Nucleosides metabolism, Nucleotides metabolism, Receptors, Purinergic P1 metabolism, Receptors, Purinergic P2 metabolism, Ribose analogs & derivatives
- Abstract
Molecular modeling of receptors for adenosine and nucleotide (P2) receptors with docked ligand, based on mutagenesis, was carried out. Adenosine 3',5'-bisphosphate derivatives act as selective P2Y1 antagonists/partial agonists. The ribose moiety was replaced with carbocyclics, smaller and larger rings, conformationally constrained rings, and acyclics, producing compounds that retained receptor affinity. Conformational constraints were built into the ribose rings of nucleoside and nucleotide ligands using the methanocarba approach, i.e. fused cyclopropane and cyclopentane rings in place of ribose, suggesting a preference for the Northern (N) conformation among ligands for P2Y1 and A1 and A3ARs.
- Published
- 2001
- Full Text
- View/download PDF
44. A peptide derived from the non-receptor-binding region of urokinase plasminogen activator inhibits glioblastoma growth and angiogenesis in vivo in combination with cisplatin.
- Author
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Mishima K, Mazar AP, Gown A, Skelly M, Ji XD, Wang XD, Jones TR, Cavenee WK, and Huang HJ
- Subjects
- Animals, Antineoplastic Agents pharmacology, Brain blood supply, Brain pathology, Brain Neoplasms physiopathology, Cell Division drug effects, Cell Movement drug effects, Cells, Cultured, Cisplatin pharmacology, Drug Therapy, Combination, Endothelium, Vascular cytology, Female, Glioblastoma physiopathology, Humans, Mice, Mice, Inbred BALB C, Peptides chemical synthesis, Peptides pharmacology, Receptors, Cell Surface metabolism, Receptors, Urokinase Plasminogen Activator, Tumor Cells, Cultured, Urokinase-Type Plasminogen Activator chemical synthesis, Urokinase-Type Plasminogen Activator metabolism, Antineoplastic Agents therapeutic use, Brain Neoplasms drug therapy, Cisplatin therapeutic use, Glioblastoma drug therapy, Neovascularization, Pathologic, Peptides therapeutic use, Urokinase-Type Plasminogen Activator therapeutic use
- Abstract
The urokinase plasminogen activator system is involved in angiogenesis and tumor growth of malignant gliomas, which are highly neovascularized and so may be amenable to antiangiogenic therapy. In this paper, we describe the activity of A6, an octamer capped peptide derived from the non-receptor-binding region of urokinase plasminogen activator. A6 inhibited human microvascular endothelial cell migration but had no effect on the proliferation of human microvascular endothelial cells or U87MG glioma cells in vitro. In contrast, A6 or cisplatin (CDDP) alone suppressed subcutaneous tumor growth in vivo by 48% and 53%, respectively, and, more strikingly, the combination of A6 plus CDDP inhibited tumor growth by 92%. Such combination treatment also greatly reduced the volume of intracranial tumor xenografts and increased survival of tumor-bearing animals when compared with CDDP or A6 alone. Tumors from the combination treatment group had significantly reduced neovascularization, suggesting a mechanism involving A6-mediated inhibition of endothelial cell motility, thereby eliciting vascular sensitivity to CDDP-mediated toxicity. These data suggest that the combination of an angiogenesis inhibitor that targets endothelial cells with a cytotoxic agent may be a useful therapeutic approach.
- Published
- 2000
- Full Text
- View/download PDF
45. The utilization of a unified pharmacophore query in the discovery of new antagonists of the adenosine receptor family.
- Author
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Webb TR, Melman N, Lvovskiy D, Ji XD, and Jacobson KA
- Subjects
- Adenosine-5'-(N-ethylcarboxamide) pharmacology, Flavonoids chemistry, Flavonoids pharmacology, Guanosine 5'-O-(3-Thiotriphosphate) metabolism, Kinetics, Ligands, Molecular Conformation, Quinazolines chemistry, Quinazolines pharmacology, Receptor, Adenosine A3, Receptors, Purinergic P1 classification, Receptors, Purinergic P1 metabolism, Structure-Activity Relationship, Triazoles chemistry, Triazoles pharmacology, Databases, Factual, Information Storage and Retrieval, Purinergic P1 Receptor Antagonists
- Abstract
Pharmacophore queries from previously known potent selective A3 antagonists were generated by Chem-X. These queries were used to search a pharmacophore database of diverse compounds (CNS-Set). In vitro assays of 186 'hits' yielded over 30 active compounds, for four adenosine receptor subtypes. This search strategy may also be applicable to the discovery of new ligands via receptor homology data.
- Published
- 2000
- Full Text
- View/download PDF
46. Pyran Template Approach to the Design of Novel A 3 Adenosine Receptor Antagonists.
- Author
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Li AH, Ji XD, Kim HS, Melman N, and Jacobson KA
- Abstract
[Table: see text] A
3 adenosine receptor antagonists have potential as anti-inflammatory, anti-asthmatic, and anti-ischemic agents. We previously reported the preparation of chemical libraries of 1,4-dihydropyridine (DHP) and pyridine derivatives and identification of members having high affinity at A3 adenosine receptors. These derivatives were synthesized through standard three-component condensation/oxidation reactions, which permitted versatile ring substitution at five positions, i.e., the central ring served as a molecular scaffold for structurally diverse substituents. We extended this template approach from the DHP series to chemically stable pyran derivatives, in which the ring NH is replaced by O and which is similarly derived from a stepwise reaction of three components. Since the orientation of substituent groups may be conformationally similar to the 1,4-DHPs, a direct comparison between the structure activity relationships of key derivatives in binding to adenosine receptors was carried out. Affinity at human A3 receptors expressed in CHO cells was determined vs. binding of [125 I]AB-MECA (N6 -(4-amino-3-iodobenzyl)-5'-N-methyl-carbamoyladenosine). There was no potency-enhancing effect, as was observed for DHPs, of 4-styryl, 4-phenylethynyl, or 6-phenyl substitutions. The most potent ligands in this group in binding to human A3 receptors were 6-methyl and 6-phenyl analogs, 3a (MRS 1704) and 4a (MRS 1705), respectively, of 3,5-diethyl 2-methyl-4-phenyl-4 H -pyran-3,5-dicarboxylate, which had Ki values of 381 and 583 nM, respectively. These two derivatives were selective for human A3 receptors vs. rat brain A1 receptors by 57-fold and 24-fold, respectively. These derivatives were inactive in binding at rat brain A2A receptors, and at recombinant human A2B receptors displayed Ki values of 17.3 and 23.2 μM, respectively. The selectivity, but not affinity, of the pyran derivatives in binding to the A3 receptor subtype was generally enhanced vs. the corresponding DHP derivatives.- Published
- 1999
- Full Text
- View/download PDF
47. Use of the triazolotriazine [3H]ZM 241385 as a radioligand at recombinant human A2B adenosine receptors.
- Author
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Ji XD and Jacobson KA
- Subjects
- Animals, CHO Cells, Cell Line, Cricetinae, Humans, Purinergic P1 Receptor Agonists, Purinergic P1 Receptor Antagonists, Radioligand Assay, Receptor, Adenosine A2B, Recombinant Proteins agonists, Recombinant Proteins antagonists & inhibitors, Recombinant Proteins metabolism, Triazines pharmacology, Triazoles pharmacology, Tritium, Receptors, Purinergic P1 metabolism, Triazines metabolism, Triazoles metabolism
- Abstract
Radiolabeled ZM 241385 (4-(2-[7-amino-2- ¿furyl¿¿1,2,4¿triazolo¿2,3-a¿¿1,3,5¿triazin-5-ylaminoethyl)p henol), has previously been used as a high affinity radioligand for the labeling of A2A adenosine receptors in cell membranes. Another subtype, the A2B receptor, is the least well-defined subtype of adenosine receptors and lacks selective pharmacological probes. In the present study, we have used [3H]ZM 241385 as a radioligand to label recombinant human A2B adenosine receptors in HEK-293 cell membranes, that do not express A2A adenosine receptors, and found that the pharmacological profile is consistent with the SAR of A2B receptors. Saturable, specific binding (Kd 33.6 nM, Bmax 4.48 pmol/mg protein) that was best described by a one-site model was found, and specific binding was approximately 75% of total binding. [3H]ZM 241385 binding was displaceable by a large number of compounds known to interact with A2B receptors; thus, this method has promise as a tool in the search for agonists and antagonists selective for this subtype. Xanthine analogs, which are antagonists, proved to be the most potent displacers. The Ki of XAC, xanthine amine congener, was 12.3 nM, while CPX (8-cyclopentyl-1,3-dipropylxanthine) was less potent. The non-selective triazoloquinazoline antagonist CGS 15943 (Ki 16.4 nM), which is similar in structure to ZM 241385, was slightly less potent than XAC. The non-xanthine A2B-antagonist alloxazine displaced [3H]ZM 241385-binding with a Ki of 462 nM, similar to its affinity in functional assays. Adenosine derivatives known to activate this receptor subtype, such as NECA (5'-N-ethylcarboxamidoadenosine) and R-PIA (N6-phenylisopropyladenosine), were considerably less potent than the 8-substituted xanthines examined.
- Published
- 1999
48. Monoclonal anti-androgen receptor antibodies: production, characterization and potential diagnostic applications.
- Author
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Shih CC, Young WJ, Wang CH, Jin LP, Ji XD, Guan Q, Wang M, and Chang C
- Subjects
- Animals, Antibody Formation, Epitopes analysis, Humans, Male, Mice, Mice, Inbred BALB C, Paraffin Embedding, Prostate metabolism, Prostatic Neoplasms metabolism, Receptors, Androgen analysis, Receptors, Androgen metabolism, Solubility, Staining and Labeling methods, Tumor Cells, Cultured, Antibodies, Monoclonal, Enzyme-Linked Immunosorbent Assay methods, Flow Cytometry methods, Prostatic Neoplasms immunology, Receptors, Androgen immunology
- Abstract
Several monoclonal antibodies (mAbs) and novel mAb-based assays for the androgen receptors (AR) have been developed. Large amounts of the recombinant human AR protein produced by a baculovirus expression system were used as an antigen to produce mAbs. Twenty-nine AR-specific mAbs were first confirmed by Western blot analysis and were then characterized for their immunoglobulin isotypes, epitopes, and epitope localization in AR. Novel assays using flow cytometry and sandwich enzyme-linked immunosorbent assays (ELISA) were established to detect AR-expressing cells and to quantify soluble AR protein, respectively. Using immunostaining, we identified several anti-AR mAbs exclusively recognizing AR within the nuclei of the prostate cancer cell line LNCaP and of prostate tissues in both frozen and paraffin-embedded sections, whereas other mAbs could detect AR in both nuclear and cytoplasmic compartments. Interestingly, certain mAbs, such as G122-25 and G122-77, could distinguish the androgen-bound AR from the unoccupied AR. In sum, many purified AR protein and anti-AR mAbs, together with the assays developed, could be powerful tools for the study of functional AR and for the diagnosis of prostatic cancers.
- Published
- 1999
- Full Text
- View/download PDF
49. Selective A(3) adenosine receptor antagonists: water-soluble 3, 5-diacyl-1,2,4-trialkylpyridinium salts and their oxidative generation from dihydropyridine precursors.
- Author
-
Xie R, Li AH, Ji XD, Melman N, Olah ME, Stiles GL, and Jacobson KA
- Subjects
- Adenylyl Cyclase Inhibitors, Animals, CHO Cells, Cerebral Cortex metabolism, Cricetinae, Enzyme Inhibitors chemical synthesis, Enzyme Inhibitors chemistry, Enzyme Inhibitors metabolism, Enzyme Inhibitors pharmacology, Humans, In Vitro Techniques, Ligands, Oxidation-Reduction, Pyridinium Compounds chemistry, Pyridinium Compounds metabolism, Pyridinium Compounds pharmacology, Radioligand Assay, Rats, Receptor, Adenosine A3, Solubility, Structure-Activity Relationship, Dihydropyridines chemistry, Purinergic P1 Receptor Antagonists, Pyridinium Compounds chemical synthesis
- Abstract
A(3) adenosine receptor antagonists are sought for their potential antiinflammatory, antiasthmatic, and antiischemic properties. We have found that 3,5-diacyl-1,2,4-trialkyl-6-phenylpyridinium derivatives constitute a novel class of selective A(3) adenosine receptor antagonists. The structure-activity relationships of this class of antagonists, incorporating the 3-thioester, have been explored. The most potent analogue in this group was 2, 4-diethyl-1-methyl-3-(ethylsulfanylcarbonyl)-5-ethyloxycarbonyl -6-phe nylpyridinium iodide (11), which had an equilibrium inhibition constant (K(i)) value of 219 nM at human A(3) receptors (binding of [(125)I]AB-MECA (N(6)-(4-amino-3-iodobenzyl)-5'-N-methylcarbamoyladenosine)) expressed in Chinese hamster ovary (CHO) cells and >10 microM at rat brain A(1) and A(2A) receptors and at recombinant human A(2B) receptors. Compound 11 could be generated through oxidation of the corresponding 3,5-diacyl-1,2,4-trialkyl-6-phenyl-1,4-dihydropyridine, 24, with iodine or in the presence of rat brain homogenates. A 6-cyclopentyl analogue was shown to increase affinity at human A(3) receptors upon oxidation from the 1-methyl-1,4-dihydropyridine analogue, 25, to the corresponding pyridinium derivative, 23 (K(i) 695 nM), suggesting a prodrug scheme. Homologation of the N-methylpyridinium derivatives to N-ethyl and N-propyl at the 1-position caused a progressive reduction in the affinity at A(3) receptors. Modifications of the alkyl groups at the 2-, 3-, 4-, and 5-positions failed to improve potency in binding at A(3) receptors. The pyridinium antagonists are not as potent as other recently reported, selective A(3) receptor antagonists; however, they display uniquely high water solubility (43 mM for 11). Compound 11 antagonized the inhibition of adenylate cyclase elicited by IB-MECA in CHO cells expressing the human A(3) adenosine receptor, with a K(B) value of 399 nM, and did not act as an agonist, demonstrating that the pyridinium salts are pure antagonists.
- Published
- 1999
- Full Text
- View/download PDF
50. Acyl-Hydrazide Derivatives of a Xanthine Carboxylic Congener (XCC) as Selective Antagonists at Human A 2B Adenosine Receptors.
- Author
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Kim YC, Karton Y, Ji XD, Melman N, Linden J, and Jacobson KA
- Abstract
The structure-activity relationships (SAR) of 8-phenyl-1,3-dipropylxanthine derivatives in binding to recombinant human A
2B adenosine receptors were explored, in order to identify selective antagonists. Based on the finding of receptor selectivity in MRS 1204, containing an N-hydroxysuccinimide ester attached through the p -position of the 8-phenyl substituent [Jacobson et al. (1999): Drug Dev. Res., 47:45-53], a hydrazide and its more stable imide derivatives were synthesized. The hydrazide of XCC (8-[4-[[[carboxy]methyl]oxy]phenyl]-1,3-dipropylxanthine) was acylated with a variety of mono- and dicarboxylic acids. Ki values were determined in the adenosine receptor binding assays. At recombinant human A2B receptors expressed in membranes of HEK-293 cells, antagonist radioligands used were the xanthine125 I-ABOPX (125 I-3-(4-amino-3-iodobenzyl)-8-oxyacetate-1-propyl-xanthine) and the nonxanthine antagonist [3 H]ZM 241385 ([3 H]4-(2-[7-amino-2-{furyl}{1,2,4}triazolo{2,3-a}{1,3,5}triazin-5-ylamino-ethyl)phenol). The initial screening utilized rat A1 /A2A receptors and human A3 receptors, and selected compounds were examined at the human A1 /A2A subtypes. A 1,2-dimethylmaleimide derivative, 14 (MRS 1595), bound to human A2B receptors with a Ki of 19 nM and proved to be selective vs. human A1 /A2A /A3 receptors by 160-, 100-, and 35-fold, respectively. Enprofylline (3-propylxanthine) is slightly selective for A2B receptors, suggesting removal of the 1-propyl group; however, combination of the 1-H-3-Pr and 8-phenyl substituents eliminated the selectivity. Other potent and moderately selective A2B antagonists were a tetrahydrophthaloyl derivative 18b (MRS 1614, Ki value 10 nM) and amino acid conjugates of the XCC-hydrazide, i.e., the glutarimide 24b (MRS 1626, Ki value 13 nM), and protected dipeptide 27 (MRS 1615, Ki value 11 nM). Drug Dev. Res. 47:178-188, 1999.- Published
- 1999
- Full Text
- View/download PDF
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