85 results on '"Lewis CS"'
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2. The lion, the witch and the wardrobe
- Author
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Lewis, CS
- Published
- 2009
3. Local antibiotic delivery with demineralized bone matrix.
- Author
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Lewis CS, Supronowicz PR, Zhukauskas RM, Gill E, and Cobb RR
- Abstract
A method of care for these infected nonunions is prolonged intravenous systemic antibiotic treatment and implantation of methyl methacrylate antibiotic carrier beads to delivery high local doses of antibiotics. This method requires a second surgery to remove the beads once the infection has cleared. Recent studies have investigated the use of biodegradable materials that have been impregnated with antibiotics as tools to treat bone infections. In the present study, human demineralized bone matrix (DBM) was investigated for its ability to be loaded with an antibiotic. The data presented herein demonstrates that this osteoinductive and biodegradable material can be loaded with gentamicin and release clinically relevant levels of the drug for at least 13 days in vitro. This study also demonstrates that the antibiotic loaded onto the graft has no adverse effects on the osteoinductive nature of the DBM as measured in vitro and in vivo. This bone void filler may represent a promising option for local antibiotic delivery in orthopedic applications. [ABSTRACT FROM AUTHOR]
- Published
- 2012
4. The process of coping with domestic violence and adult survivors of childhood sexual abuse.
- Author
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Griffing S, Lewis CS, Chu M, Sage R, Jospitre T, Madry L, and Primm BJ
- Abstract
Research suggests that the use of disengaged or avoidant strategies to cope with interpersonal violence contributes to the development of depressive symptoms and other psychological difficulties. Survivors of childhood sexual abuse (CSA) who are exposed to subsequent episodes of abuse may be more likely to rely on disengaged coping strategies, placing them at elevated risk of psychological symptomatology. In this study, we explored the interrelationships between coping, depression, and self-esteem in an ethnically diverse sample of domestic violence survivors (N = 219) with and without a history of CSA. As predicted, CSA survivors (n = 86) reported significantly greater use of disengaged coping strategies (wishful thinking, self-criticism, and social withdrawal) than non-CSA survivors (n = 133). As hypothesized, both a CSA history and the use of disengaged coping significantly predicted higher levels of depression and lower self- esteem. Clinical implications of the findings are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
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5. Metastatic epidural spinal cord compression from testicular yolk sac tumor: case report and literature review.
- Author
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Galang CAT, Hernandez N, Lewis CS, and Pham MH
- Abstract
Background: Yolk sac tumor (YST), or endodermal sinus tumor, is classically associated with pediatric populations. Metastasis to the spine rarely occurs, usually involving the lower thoracic or lumbar vertebrae. The objective of this report is to present a rare case of YST metastasis to the lower cervical and upper thoracic vertebrae in an adult male. A case-based review of the literature on metastatic YSTs was also performed as an update to the relevant literature., Case Description: A 28-year-old male with a history of YST presented to our institution with urinary retention, increasing weakness in the upper extremities, and acute onset lower extremity weakness. Computed tomography (CT) and magnetic resonance imaging (MRI) scans confirmed evidence of metastasis from a known YST with symptomatic cord compression. The patient was treated with surgical excision via decompressive laminectomies with instrumentation as described, and histopathologic analysis of the specimen confirmed YST metastasis. His disease recurred one year after index surgery. He succumbed to his disease despite repeated debulking., Conclusions: Metastasis of YST is rare, but metastasis to lower cervical and upper thoracic vertebrae is possible. YSTs are usually treated via primary surgical resection. Systemic chemotherapy and radiation may prevent recurrence. However, individualized treatment is imperative for improved patient outcomes., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-24-28/coif). M.H.P. reports grants from Medtronic and consulting fees from Medtronic, Globus, Thompson Surgical, and NovApproach. The other authors have no conflicts of interest to declare., (2024 AME Publishing Company. All rights reserved.)
- Published
- 2024
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6. Single position robot-assisted pedicle screw placement with S2-alar-iliac fixation in lateral decubitus: cadaveric feasibility study and early clinical experience.
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Stone LE, Broughton AG, Lewis CS, and Pham MH
- Subjects
- Humans, Male, Aged, Middle Aged, Retrospective Studies, Cadaver, Sacrum surgery, Sacrum diagnostic imaging, Ilium surgery, Female, Pedicle Screws, Feasibility Studies, Robotic Surgical Procedures methods, Robotic Surgical Procedures instrumentation, Spinal Fusion methods, Spinal Fusion instrumentation, Lumbar Vertebrae surgery, Lumbar Vertebrae diagnostic imaging
- Abstract
Objectives: Single position lateral fusion with robotic assistance eliminates the need for surgical staging while harnessing the precision of robotic adjuncts. We expand on this technique by demonstrating the technical feasibility of placing bilateral pedicle screws with S2-alar-iliac (S2AI) fixation while in the lateral position., Methods: A cadaveric study was performed using 12 human specimens. A retrospective clinical series was also performed for patients who had undergone robot-assisted placement of S2AI screws in lateral decubitus between June 2020 and June 2022. Case demographics, implant placement time, implant size, screw accuracy, and complications were recorded. Early postoperative radiographic outcomes were reported., Results: In the cadaveric series, a total of 126 screws were placed with robotic assistance in 12 cadavers of which 24 screws were S2AI. There were four breaches from pedicle screws and none with S2AI screws for an overall accuracy rate of 96.8%. In the clinical series, four patients (all male, mean age 65.8 years) underwent single position lateral surgery with S2AI distal fixation. Mean BMI was 33.6 and mean follow-up was 20.5 months. Mean radiographic improvements were lumbar lordosis 12.3 ± 4.7°, sagittal vertical axis 1.5 ± 2.1 cm, pelvic tilt 8.5 ± 10.0°, and pelvic incidence-lumbar lordosis mismatch 12.3 ± 4.7°. A total of 42 screws were placed of which eight screws were S2AI. There were two breaches from pedicle screws and none from S2AI screws for an overall accuracy rate of 95.2%. No repositioning or salvage techniques were required for the S2AI screws., Conclusions: We demonstrate here the technical feasibility of single position robot-assisted placement of S2-alar-iliac screws in the lateral decubitus position for single position surgery., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2024
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7. Primary gastric diffuse large B-cell lymphoma: A multicentre retrospective study.
- Author
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Lewis CS, Joy G, Jensen P, Barraclough A, Franco N, Talaulikar D, Hawkes EA, El-Galaly TC, Villa D, Dickinson M, Seymour JF, and Cheah CY
- Subjects
- Humans, Male, Female, Middle Aged, Aged, Retrospective Studies, Adult, Aged, 80 and over, Rituximab therapeutic use, Rituximab administration & dosage, Vincristine therapeutic use, Vincristine administration & dosage, Prednisone therapeutic use, Prednisone administration & dosage, Cyclophosphamide therapeutic use, Cyclophosphamide administration & dosage, Doxorubicin therapeutic use, Doxorubicin administration & dosage, Helicobacter Infections complications, Helicobacter Infections drug therapy, Helicobacter pylori, Positron-Emission Tomography, Lymphoma, Non-Hodgkin, Lymphoma, Large B-Cell, Diffuse mortality, Lymphoma, Large B-Cell, Diffuse therapy, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Stomach Neoplasms therapy, Stomach Neoplasms pathology
- Abstract
Primary gastric diffuse large B-cell lymphoma (PG-DLBCL) accounts for the majority of extra-nodal DLBCL. Even so, literature is lacking on early, localised presentations. We studied a cohort of patients with stage I disease, diagnosed between 2006 and 2018, from six centres between Australia, Canada and Denmark. Our goal was to characterise outcomes, review treatment and investigate the role of interim positron emission tomography (iPET). Thirty-seven eligible patients were identified. The median duration of follow-up was 42.2 months. All received chemoimmunotherapy with 91.9% (n = 34) given rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP). 35.1% (n = 13) underwent consolidative radiotherapy. Eighteen patients were H. pylori positive and 11 had the documentation of H. pylori eradication therapy. The 4-year progression-free survival and overall survival of R-CHOP was 88% (95% CI: 71-95) and 91% (95% CI: 75-97) respectively. All patients who achieved a partial metabolic response or complete metabolic response on iPET went on to achieve complete response at the end of treatment. R-CHOP-based therapy with iPET assessment appears to offer favourable outcomes, with radiotherapy and H. pylori eradication therapy implemented on a case-by-case basis., (© 2024 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)
- Published
- 2024
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8. Understanding American Indian tribal college student knowledge, attitudes, beliefs, and behaviors surrounding alternative tobacco products.
- Author
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Goeckner R, Lewis CS, Simon AL, Pacheco J, Hale J, Choi WS, and Daley CM
- Abstract
Objectives: To examine knowledge, attitudes, beliefs, and behaviors about alternative tobacco products among American Indian tribal college students., Participants: One hundred and five tribal college students., Methods: Focus groups, one interview, and demographic surveys., Results: Tobacco use varied across the sample with 35.2% of the participants being users of ENDS products and 29.5% were cigarette smokers. Overall, participants viewed electronic nicotine delivery systems and chewing tobacco as primary examples of alternative tobacco products and described a generational divide between alternative and conventional tobacco product use. Alternative tobacco products were not considered suitable for use in traditional contexts., Conclusions: Previously successful cessation programs in this population have relied on cultural tailoring related to traditional tobacco use in American Indian communities. Our findings suggest that this strategy may be less effective for addressing alternative tobacco use. Reliance on the importance of family relationships may prove more impactful in future programming.
- Published
- 2024
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9. First-in-Class Humanized Antibody against Alternatively Spliced Tissue Factor Augments Anti-Metastatic Efficacy of Chemotherapy in a Preclinical Model of Pancreatic Ductal Adenocarcinoma.
- Author
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Lewis CS, Backman C, Ahsan S, Cliff A, Hariharan A, Yeh JJ, Zhang X, Xie C, Sohal DPS, and Bogdanov VY
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- Humans, Thromboplastin, Gemcitabine, Antibodies, Monoclonal, Humanized therapeutic use, Leukocytosis drug therapy, Cell Line, Tumor, Deoxycytidine pharmacology, Paclitaxel therapeutic use, Carcinoma, Pancreatic Ductal pathology, Pancreatic Neoplasms pathology
- Abstract
Alternatively spliced tissue factor (asTF) promotes the progression of pancreatic ductal adenocarcinoma (PDAC) by activating β1-integrins on PDAC cell surfaces. hRabMab1, a first-in-class humanized inhibitory anti-asTF antibody we recently developed, can suppress PDAC primary tumor growth as a single agent. Whether hRabMab1 has the potential to suppress metastases in PDAC is unknown. Following in vivo screening of three asTF-proficient human PDAC cell lines, we chose to make use of KRAS G12V-mutant human PDAC cell line PaCa-44, which yields aggressive primary orthotopic tumors with spontaneous spread to PDAC-relevant anatomical sites, along with concomitant severe leukocytosis. The experimental design featured orthotopic tumors formed by luciferase labeled PaCa-44 cells; administration of hRabMab1 alone or in combination with gemcitabine/paclitaxel (gem/PTX); and the assessment of the treatment outcomes on the primary tumor tissue as well as systemic spread. When administered alone, hRabMab1 exhibited poor penetration of tumor tissue; however, hRabMab1 was abundant in tumor tissue when co-administered with gem/PTX, which resulted in a significant decrease in tumor cell proliferation; leukocyte infiltration; and neovascularization. Gem/PTX alone reduced primary tumor volume, but not metastatic spread; only the combination of hRabMab1 and gem/PTX significantly reduced metastatic spread. RNA-seq analysis of primary tumors showed that the addition of hRabMab1 to gem/PTX enhanced the downregulation of tubulin binding and microtubule motor activity. In the liver, hRabMab1 reduced liver metastasis as a single agent. Only the combination of hRabMab1 and gem/PTX eliminated tumor cell-induced leukocytosis. We here demonstrate for the first time that hRabMab1 may help suppress metastasis in PDAC. hRabMab1's ability to improve the efficacy of chemotherapy is significant and warrants further investigation.
- Published
- 2024
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10. Everyday discrimination for American Indian tribal college students enrolled in the Internet All Nations Breath of Life program.
- Author
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Hale JW, Pacheco JA, Lewis CS, Swimmer L, Daley SM, Nazir N, Daley CM, and Choi WS
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- Humans, Students, Universities, Depression epidemiology, Body Image, Indians, North American, Racism, Smoking Cessation, Perceived Discrimination
- Abstract
Objective: Identify factors associated with perceived discrimination, including depression, body image satisfaction, body mass index (BMI), social support, stress, and self-reported social status., Participants: A total of 249 American Indian tribal college students., Methods: Students were recruited for an Internet-based smoking cessation program. A total of 249 students answered the Everyday Discrimination Scale questions to assess perceived discrimination. We conducted bivariate analyses to determine potential significant associations between perceived discrimination and health outcomes at baseline., Results: We found 63% of the sample reported racial discrimination. Among those who reported moderate/severe depression, 87% reported discrimination. Among those who were not satisfied with their body image, 70% reported racial discrimination., Conclusion: Reports of racial discrimination are highly prevalent among our participants. We found reports of discrimination are significantly associated with depression and dissatisfaction with body image. Our study highlights a high priority population that perceives racial discrimination, potentially increasing their risk for adverse health outcomes.
- Published
- 2023
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11. Fertility preservation discussions, referral and follow-up in male-to-female and female-to-male adolescent transgender patients.
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Komorowski AS, Fisher AR, Jungheim ES, Lewis CS, and Omurtag KR
- Subjects
- Child, Humans, Male, Adolescent, Female, Follow-Up Studies, Semen, Referral and Consultation, Fertility Preservation, Transgender Persons
- Abstract
The number of patients seeking transgender healthcare is growing, and there is a potential impact of gender-affirming therapies on fertility. The use of fertility preservation (FP), particularly among transgender adolescents, has been limited. We aimed to examine differences in FP counselling, referral and utilisation between male-to-female (MtF) and female-to-male (FtM) transgender adolescents. A retrospective review of the medical records of patients ages 12-17 seen at an academic medical centre between 2012 and 2017 with a diagnosis of gender dysphoria was conducted. A total of 22 MtF and 45 FtM adolescents were included. The counselling on the potential fertility impact of gender-affirming therapy was documented in 55%, and of those counselled, 73% were counselled before receiving medication. There was no significant difference between the timing of counselling for MtF versus FtM adolescents. Of patients with documented reproductive wishes, 77% reported either desire for adopted children or no desire for biological children. Among patients offered FP referral, 2 (22.2%) MtF and 3 (12.5%) FtM patients accepted; both MtF patients cryopreserved sperm. While most adolescents were counselled on the fertility impact of gender-affirming therapy, there is room for improvement as 45% of patients had no documented counselling. The rate of transgender adolescents pursuing FP consultation and gamete cryopreservation was low, consistent with prior studies in this population.
- Published
- 2023
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12. N 4 -Hydroxycytidine/Molnupiravir Inhibits RNA-Virus Induced Encephalitis by Producing Mutated Viruses with Reduced Fitness.
- Author
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Ojha D, Hill CS, Zhou S, Evans AB, Leung JM, Lewis CS, Amblard F, Schinazi RF, Baric RS, Peterson KE, and Swanstrom R
- Abstract
A diverse group of RNA viruses including Rabies, Polio, La Crosse, West Nile, Zika, Nipah, Eastern and Western equine encephalitis, Venezuelan equine encephalitis, Japanese encephalitis, and tick-borne encephalitis viruses have the ability to gain access to and replicate in the central nervous system (CNS), causing severe neurological disease. Current treatment for these patients is generally limited to supportive care. To address the need for a generalizable antiviral, we utilized a strategy of mutagenesis to limit virus replication. We evaluated ribavirin (RBV), favipiravir (FAV) and N
4 -hydroxycytidine (NHC) against La Crosse virus (LACV) which is the primary cause of pediatric arboviral encephalitis cases in North America. NHC was more potent than RBV or FAV in neuronal cells. Oral administration of molnupiravir (MOV), the 5'-isobutyryl prodrug of NHC, decreased neurological disease development by 32% following intraperitoneal (IP) infection of LACV. MOV also reduced disease by 23% when virus was administered intranasally (IN). NHC and MOV produced less fit viruses by incorporating predominantly G-to-A or C-to-U mutations. Furthermore, NHC also inhibited two other orthobunyaviruses, Jamestown Canyon virus and Cache Valley virus. Collectively, these studies indicate that NHC/MOV has therapeutic potential to inhibit virus replication and subsequent neurological disease caused by this neurotropic RNA virus.- Published
- 2023
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13. Minimally Invasive C1-3 Posterior Spinal Fusion With Intraoperative O-arm Navigation: 2-Dimensional Operative Video.
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Lewis CS, Stone LE, Forseth KJ, and Pham MH
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- Humans, Tomography, X-Ray Computed, Imaging, Three-Dimensional methods, Treatment Outcome, Surgery, Computer-Assisted methods, Spinal Fusion methods
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- 2023
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14. Potential utility of a multi-component coagulation factor panel to calculate MELD scores and assess the risk of portal vein thrombosis in chronic liver disease.
- Author
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Lewis CS, Bari K, Xie C, Sherman KE, Vasse M, Van Dreden P, and Bogdanov VY
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- Humans, Portal Vein pathology, Liver Cirrhosis, Severity of Illness Index, Blood Coagulation Factors metabolism, End Stage Liver Disease complications, End Stage Liver Disease surgery, Liver Diseases complications, Liver Diseases pathology, Venous Thrombosis diagnosis
- Abstract
Background: Current quantitative approaches to assess chronic liver disease (CLD) severity have limitations. Further, portal vein thrombosis (PVT) pre-liver transplant (LT) is a major contributor to morbidity in CLD; the means of detecting and/or predicting PVT are limited. We sought to explore whether plasma coagulation factor activity levels can serve as a substitute for prothrombin time/international normalized ratio (PT/INR) in the Model for End-stage Liver Disease (MELD), and/or help assess the risk of PVT., Methods: Plasma activity levels of Factor V (FV), Factor VIII (FVIII), Protein C (PC), and Protein S (PS) and the concentrations of D-dimer, sP-selectin, and asTF were assessed in two cohorts of CLD patients (ambulatory, n = 42; LT, n = 43)., Results: FV and PC activity levels strongly correlated with MELD scores, which enabled the development of a novel scoring system based on multiple linear regressions of the correlations of FV and PC activity with MELD-Na that substitutes PT/INR. Six-month and 1-year follow-up revealed that our novel approach was non-inferior to MELD-Na at predicting mortality. A significant inverse correlation between FVIII activity levels and PVT was found in the LT cohort (p = 0.010); FV and PS activity levels were in-trend (p = 0.069, p = 0.064). We developed a logistic regression-based compensation score to identify patients at risk of PVT., Conclusions: We demonstrate that FV and PC activity levels may be used to replace PT/INR in MELD scoring. We also show the potential of using the combination of FV, FVIII, and PS activity levels to assess the risk of PVT in CLD., (© 2023. The Author(s).)
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- 2023
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15. Direct Anterior Repair of Spontaneous Ventral Cervical Cerebrospinal Fluid Leak: 2-Dimensional Operative Video.
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Lewis CS, Diaz-Aguilar LD, and Pham MH
- Subjects
- Humans, Neurosurgical Procedures, Cerebrospinal Fluid Leak diagnostic imaging, Cerebrospinal Fluid Leak surgery, Neck
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- 2023
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16. Minimally Invasive Posterior Cervical Laminectomy: 2-Dimensional Operative Video.
- Author
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Lewis CS, Stone LE, and Pham MH
- Subjects
- Humans, Minimally Invasive Surgical Procedures methods, Laminectomy methods, Spinal Stenosis surgery
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- 2023
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17. Integrin regulation by tissue factor promotes cancer stemness and metastatic dissemination in breast cancer.
- Author
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Ünlü B, Kocatürk B, Rondon AMR, Lewis CS, Swier N, van den Akker RFP, Krijgsman D, Noordhoek I, Blok EJ, Bogdanov VY, Ruf W, Kuppen PJK, and Versteeg HH
- Subjects
- Humans, Female, Cell Line, Tumor, Integrin beta1 genetics, Integrin beta1 metabolism, Integrin alpha3beta1, Thromboplastin, Breast Neoplasms pathology
- Abstract
Tissue Factor (TF) is the initiator of blood coagulation but also functions as a signal transduction receptor. TF expression in breast cancer is associated with higher tumor grade, metastasis and poor survival. The role of TF signaling on the early phases of metastasis has never been addressed. Here, we show an association between TF expression and metastasis as well as cancer stemness in 574 breast cancer patients. In preclinical models, blockade of TF signaling inhibited metastasis tenfold independent of primary tumor growth. TF blockade caused a reduction in epithelial-to-mesenchymal-transition, cancer stemness and expression of the pro-metastatic markers Slug and SOX9 in several breast cancer cell lines and in ex vivo cultured tumor cells. Mechanistically, TF forms a complex with β1-integrin leading to inactivation of β1-integrin. Inhibition of TF signaling induces a shift in TF-binding from α3β1-integrin to α6β4 and dictates FAK recruitment, leading to reduced epithelial-to-mesenchymal-transition and tumor cell differentiation. In conclusion, TF signaling inhibition leads to reduced pro-metastatic transcriptional programs, and a subsequent integrin β1 and β4-dependent reduction in metastasic dissemination., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)
- Published
- 2022
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18. Functional Characteristics and Regulated Expression of Alternatively Spliced Tissue Factor: An Update.
- Author
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Matiash K, Lewis CS, and Bogdanov VY
- Abstract
In human and mouse, alternative splicing of tissue factor's primary transcript yields two mRNA species: one features all six TF exons and encodes full-length tissue factor (flTF), and the other lacks exon 5 and encodes alternatively spliced tissue factor (asTF). flTF, which is oftentimes referred to as "TF", is an integral membrane glycoprotein due to the presence of an alpha-helical domain in its C-terminus, while asTF is soluble due to the frameshift resulting from the joining of exon 4 directly to exon 6. In this review, we focus on asTF-the more recently discovered isoform of TF that appears to significantly contribute to the pathobiology of several solid malignancies. There is currently a consensus in the field that asTF, while dispensable to normal hemostasis, can activate a subset of integrins on benign and malignant cells and promote outside-in signaling eliciting angiogenesis; cancer cell proliferation, migration, and invasion; and monocyte recruitment. We provide a general overview of the pioneering, as well as more recent, asTF research; discuss the current concepts of how asTF contributes to cancer progression; and open a conversation about the emerging utility of asTF as a biomarker and a therapeutic target.
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- 2021
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19. A First-In-Class, Humanized Antibody Targeting Alternatively Spliced Tissue Factor: Preclinical Evaluation in an Orthotopic Model of Pancreatic Ductal Adenocarcinoma.
- Author
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Lewis CS, Karve A, Matiash K, Stone T, Li J, Wang JK, Versteeg HH, Aronow BJ, Ahmad SA, Desai PB, and Bogdanov VY
- Abstract
In 2021, pancreatic ductal adenocarcinoma (PDAC) is the 3
rd leading cause of cancer deaths in the United States. This is largely due to a lack of symptoms and limited treatment options, which extend survival by only a few weeks. There is thus an urgent need to develop new therapies effective against PDAC. Previously, we have shown that the growth of PDAC cells is suppressed when they are co-implanted with RabMab1, a rabbit monoclonal antibody specific for human alternatively spliced tissue factor (asTF). Here, we report on humanization of RabMab1, evaluation of its binding characteristics, and assessment of its in vivo properties. hRabMab1 binds asTF with a KD in the picomolar range; suppresses the migration of high-grade Pt45.P1 cells in Boyden chamber assays; has a long half-life in circulation (~ 5 weeks); and significantly slows the growth of pre-formed orthotopic Pt45.P1 tumors in athymic nude mice when administered intravenously. Immunohistochemical analysis of tumor tissue demonstrates the suppression of i) PDAC cell proliferation, ii) macrophage infiltration, and iii) neovascularization, whereas RNAseq analysis of tumor tissue reveals the suppression of pathways that promote cell division and focal adhesion. This is the first proof-of-concept study whereby a novel biologic targeting asTF has been investigated as a systemically administered single agent, with encouraging results. Given that hRabMab1 has a favorable PK profile and is able to suppress the growth of human PDAC cells in vivo , it comprises a promising candidate for further clinical development., Competing Interests: Authors JL and JKW were employed by LakePharma, Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Lewis, Karve, Matiash, Stone, Li, Wang, Versteeg, Aronow, Ahmad, Desai and Bogdanov.)- Published
- 2021
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20. High-Glucose-Induced Rab20 Upregulation Disrupts Gap Junction Intercellular Communication and Promotes Apoptosis in Retinal Endothelial and Müller Cells: Implications for Diabetic Retinopathy.
- Author
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Kim D, Lewis CS, Sarthy VP, and Roy S
- Abstract
To investigate whether high glucose (HG) alters Rab20 expression and compromises gap junction intercellular communication (GJIC) and cell survival, retinal cells were studied for altered intracellular trafficking of connexin 43 (Cx43). Retinal endothelial cells (RRECs) and retinal Müller cells (rMCs) were grown in normal (N; 5 mM glucose) or HG (30 mM glucose) medium for seven days. In parallel, cells grown in HG medium were transfected with either Rab20 siRNA or scrambled siRNA as a control. Rab20 and Cx43 expression and their localization and distribution were assessed using Western Blot and immunostaining, respectively. Changes in GJIC activity were assessed using scrape load dye transfer, and apoptosis was identified using differential dye staining assay. In RRECs or rMCs grown in HG medium, Rab20 expression was significantly increased concomitant with a decreased number of Cx43 plaques. Importantly, a significant increase in the number of Cx43 plaques and GJIC activity was observed in cells transfected with Rab20 siRNA. Additionally, Rab20 downregulation inhibited HG-induced apoptosis in RRECs and rMCs. Results indicate HG-mediated Rab20 upregulation decreases Cx43 localization at the cell surface, resulting in compromised GJIC activity. Reducing Rab20 expression could be a useful strategy in preventing HG-induced vascular and Müller cell death associated with diabetic retinopathy.
- Published
- 2020
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21. Management of Giant Sacral Pseudomeningocele in Revision Spine Surgery.
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Al Jammal OM, Wali AR, Lewis CS, Zaldana MV, Suliman AS, and Pham MH
- Abstract
Background: Giant pseudomeningoceles are an uncommon complication of spine surgery. Surgical management and extirpation can be difficult, and guidelines remain unclear., Methods: Here, we present a 56-year-old female patient with a history of grade III L5-S1 spondylolisthesis who was treated with 2 prior spine surgeries. The patient was treated with bone grafting for pseudarthrosis and instrumentation from L4 to ilium. After unsuccessful intraoperative and postoperative cerebrospinal fluid drainage and dural repair, the patient presented to the emergency room with debilitating positional headaches., Results: The patient underwent dural repair with bovine pericardial patch inlay sutured with 7-0 prolene, blood patch, and a dural sealant. Plastic surgery performed a layered closure, using acellular dermal matrix over the dural closure. The bilateral paraspinal flaps were advanced medially to cover the entirety of the acellular dermal matrix, and the fasciocutaneous flaps were then advanced to the midline for a watertight closure. At 3-month follow-up, the patient was headache free and had returned to her activities of daily living., Conclusions: We conclude that early consultation with plastic surgery can be greatly beneficial to effectively extirpate dead space and resolve giant sacral pseudomeningoceles, especially if there is concern of persistent cerebrospinal fluid leakage due to relatively immobile avascular soft tissue as a result of prior revision surgery., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2020 ISASS.)
- Published
- 2020
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22. Enhanced Efficacy of Combination of Gemcitabine and Phosphatidylserine-Targeted Nanovesicles against Pancreatic Cancer.
- Author
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N'Guessan KF, Davis HW, Chu Z, Vallabhapurapu SD, Lewis CS, Franco RS, Olowokure O, Ahmad SA, Yeh JJ, Bogdanov VY, and Qi X
- Subjects
- Animals, Biomarkers, Cell Cycle drug effects, Cell Line, Tumor, Deoxycytidine administration & dosage, Disease Models, Animal, Flow Cytometry, Gene Expression, Humans, Mice, Pancreatic Neoplasms drug therapy, Pancreatic Neoplasms mortality, Pancreatic Neoplasms pathology, Xenograft Model Antitumor Assays, Gemcitabine, Antineoplastic Agents administration & dosage, Deoxycytidine analogs & derivatives, Nanoparticles chemistry, Phosphatidylserines administration & dosage
- Abstract
Phosphatidylserine (PS) is often externalized in viable pancreatic cancer cells and is therapeutically targetable using PS-selective drugs. One of the first-line treatments for advanced pancreatic cancer disease, gemcitabine (GEM), provides only marginal benefit to patients. We therefore investigated the therapeutic benefits of combining GEM and the PS-targeting drug, saposin C-dioleoylphosphatidylserine (SapC-DOPS), for treating pancreatic ductal adenocarcinoma (PDAC). Using cell-cycle analyses and a cell surface PS-based sorting method in vitro, we observed an increase in surface PS as cells progress through the cell cycle from G1 to G2/M. We also observed that GEM treatment preferentially targets G1 phase cells that have low surface PS, resulting in an increased median surface PS level of PDAC cells. Inversely, SapC-DOPS preferentially targets high surface PS cells that are predominantly in the G2/M phase. Finally, combination therapy in subcutaneous and orthotopic PDAC tumors in vivo with SapC-DOPS and GEM or Abraxane (Abr)/GEM (one of the current standards of care) significantly inhibits tumor growth and increases survival compared with individual treatments. Our studies confirm a surface PS and cell cycle-based enhancement of cancer cytotoxicity following SapC-DOPS treatment in combination with GEM or Abr/GEM. Thus, PDAC patients treated with Abr/GEM may benefit from concurrent administration of SapC-DOPS., (Copyright © 2020 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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23. Baseline characteristics of American Indian smokeless tobacco users participating in two pilot cessation studies.
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Lewis CS, Nazir N, Daley SM, Pacheco J, Goeckner RT, Hale JW, Gunville JA, Rahman F, Choi WS, and Daley CM
- Subjects
- Adult, Counseling, Female, Health Behavior, Humans, Male, Smoking psychology, Tobacco Products, Tobacco Use, Tobacco Use Disorder psychology, American Indian or Alaska Native, Tobacco Use Cessation, Tobacco Use Disorder therapy, Tobacco, Smokeless
- Abstract
American Indians have higher rates of smokeless tobacco (SLT) use than other racial/ethnic groups in the US, yet no efficacious cessation program exists for them. Because tobacco is a sacred plant to many American Indians, it is imperative that a program respect the scared nature of tobacco while encouraging quitting recreational use. All Nations Snuff Out Smokeless (ANSOS) was designed to help American Indian SLT users quit recreational tobacco use while still using it for traditional purposes. We pilot tested the ANSOS 6-month group-based counseling program (N = 48) and a shortened version consisting of a one-time education session (N = 80). Here, we discuss the tobacco characteristics of participants at baseline in both studies. Participants across studies were more likely to be male (74.2%) and have at least a college education (65%). Participants in the one-time education sessions were younger (age 35 vs age 39) and used SLT fewer days per week (4.9 vs 5.7). Two-thirds of those in the full program reported that they often substitute SLT in locations where smoking is not allowed compared to 26%. Participants in the education sessions were more likely to report daily use of traditional tobacco (20% versus 0%). Results suggest that dual use of SLT and cigarettes needs to be addressed, as does the use of SLT to circumvent public smoking rules. The role of traditional tobacco and its relationship to lower SLT use also warrants further investigation.
- Published
- 2020
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24. Decompression Surgery versus Interspinous Devices for Lumbar Spinal Stenosis: A Systematic Review of the Literature.
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Tram J, Srinivas S, Wali AR, Lewis CS, and Pham MH
- Abstract
In this retrospective review study, the authors systematically reviewed the literature to elucidate the efficacy and complications associated with decompression and interspinous devices (ISDs) used in surgeries for lumbar spinal stenosis (LSS). LSS is a debilitating condition that affects the lumbar spinal cord and spinal nerve roots. However, a comprehensive report on the relative efficacy and complication rate of ISDs as they compare to traditional decompression procedures is currently lacking. The PubMed database was queried to identify clinical studies that exclusively investigated decompression, those that exclusively investigated ISDs, and those that compared decompression with ISDs. Only prospective cohort studies, case series, and randomized controlled trials that evaluated outcomes using the Visual Analog Scale (VAS), Oswestry Disability Index, or Japanese Orthopedic Association scores were included. A random-effects model was established to assess the difference between preoperative and the 1-2-year postoperative VAS scores between ISD surgery and lumbar decompression. This study included 40 papers that matched our criteria. Twenty-five decompression-exclusive clinical trials with 3,386 patients and a mean age of 68.7 years (range, 31-88 years) reported a 2.2% incidence rate of dural tears and a 2.6% incidence rate of postoperative infections. Eight ISD-exclusive clinical trials with 1,496 patients and a mean age of 65.1 (range, 19-89 years) reported a 5.3% incidence rate of postoperative leg pain and a 3.7% incidence rate of spinous process fractures. Seven studies that compared ISDs and decompression in 624 patients found a reoperation rate of 8.3% in ISD patients vs. 3.9% in decompression patients; they also reported dural tears in 0.32% of ISD patients vs. 5.2% in decompression patients. A meta-analysis of the randomized controlled trials found that the differences in preoperative and postoperative VAS scores between the two groups were not significant. Both decompression and ISD interventions are unique surgical interventions with different therapeutic efficacies and complications. The collected studies do not consistently demonstrate superiority of either procedure over the other but understanding the differences between the two techniques can help tailor treatment regimens for patients with LSS.
- Published
- 2020
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25. Engorged venous plexus mimicking adjacent segment disease: Case report and review of the literature.
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Hassan O, Lewis CS, Aradhyula L, Hirshman BR, and Pham MH
- Abstract
Background: An engorged venous plexus may mimic nerve compression from a herniated disk on the magnetic resonance (MR) studies as they both have similar signal intensities. During a laminectomy, if an engorged venous plexus is encountered instead of a disk herniation, there may be marked unanticipated bleeding., Case Description: A 58-year-old female who had a prior anterior lumbar interbody fusion later returned with recurrent radiculopathy. Adjacent segment disease from a spinal disk herniation was suspected based on the surgical history, physical examination, and imaging (MRI) findings. Rather than a disk, an engorged venous plexuses (EVP) was encountered intraoperatively., Conclusion: Here, we discussed our findings regarding a lumbar EVP rather than a herniated disk and reviewed the current literature. Although rare, a higher index of suspicion for these vascular malformations based on combined historical information and MRI studies should allow one to better detect and/or anticipate an EVP rather than a routine disk., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Surgical Neurology International.)
- Published
- 2020
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26. Use of a Reverse Bohlman Technique for Low-Grade Spondylolisthesis.
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Pham MH, Buchanan IA, Lewis CS, Fredrickson V, Kammen A, Bakhsheshian J, and Acosta FL
- Abstract
Background: Treatment of spondylolisthesis can be difficult with regard to patients with high sacral slopes that may prohibit placement of interbody grafts for fusions across that segment. Here, we describe placement of a reverse Bohlman technique from an anterior approach to obtain fusion across a low-grade spondylolisthesis with a high sacral slope to obtain anterior fusion., Methods: A chart review was conducted on this single patient regarding his clinical course and outcome., Results: A 54-year-old male presented with low-back pain associated with bilateral leg pain dating back several years. Plain films demonstrated a Grade II isthmic spondylolisthesis at L5-S1 with spinopelvic measurements of 73° sacral slope, 82° lumbar lordosis, 12° pelvic tilt, and 94° pelvic incidence. Magnetic resonance imaging showed bilateral L5 pars defects with diffuse degenerative disease from L4 through S1 and significant ligamentous and facet hypertrophy. He underwent an L4-5 anterior lumbar interbody fusion and an L5-S1 reverse Bohlman placement of a transvertebral transsacral titanium mesh cage. This was supplemented with a posterior decompression and instrumentation from L4-ilium. He had resolution of his radiculopathy and has maintained a good clinical outcome at 3 years follow up., Conclusions: We present here a patient with low-grade spondylolisthesis and a steep sacral slope who underwent a successful reverse Bohlman approach with long-term follow up. This report highlights the potential utility of this method as a viable alternative for patients with low-grade spondylolisthesis., Level of Evidence: IV., Clinical Relevance: Technical description of surgical technique., Competing Interests: Disclosures and DOI: The authors have no commercial relationships or financial interests to disclose., (©International Society for the Advancement of Spine Surgery 2019.)
- Published
- 2019
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27. Bilateral Vertebral Artery Occlusion After Cervical Spine Fracture Dislocation.
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Strickland B, Lewis CS, and Pham MH
- Abstract
Background: Vertebral artery injury is known to potentially occur in conjunction with blunt cervical spine trauma. Rarely, these injuries present bilaterally as complete occlusions. Twelve cases of bilateral vertebral artery occlusions after closed cervical spine trauma have been described in the reported data, nearly all of which demonstrated signs and symptoms of vertebrobasilar insufficiency and ischemia., Case Description: Our patient presented after a traumatic C5-C6 flexion-distraction injury that had resulted in bilateral locked facets and spinal cord injury and bilateral vertebral artery occlusions at the V1 segment. However, our patient did not show any cranial symptoms despite his neurovascular injury., Conclusions: We present our patient's case as a rare illustration of a bilateral vertebral artery occlusion after blunt cervical spine trauma without clinical vertebrobasilar ischemic sequelae., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
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28. KLF11 (Krüppel-Like Factor 11) Modulates Arterial Thrombosis.
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Lewis CS and Bogdanov VY
- Subjects
- Apoptosis Regulatory Proteins, Cell Cycle Proteins, Humans, Kruppel-Like Transcription Factors, Repressor Proteins, Transcription Factors, Thromboplastin, Thrombosis
- Published
- 2019
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29. mTOR kinase inhibition reduces tissue factor expression and growth of pancreatic neuroendocrine tumors.
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Lewis CS, Elnakat Thomas H, Orr-Asman MA, Green LC, Boody RE, Matiash K, Karve A, Hisada YM, Davis HW, Qi X, Mercer CA, Lucas FV, Aronow BJ, Mackman N, Versteeg HH, and Bogdanov VY
- Subjects
- Animals, Cell Line, Tumor, Humans, Mechanistic Target of Rapamycin Complex 1 metabolism, Mechanistic Target of Rapamycin Complex 2 metabolism, Mice, Nude, Neuroendocrine Tumors enzymology, Neuroendocrine Tumors genetics, Neuroendocrine Tumors pathology, Pancreatic Neoplasms enzymology, Pancreatic Neoplasms genetics, Pancreatic Neoplasms pathology, Promoter Regions, Genetic, Signal Transduction, TOR Serine-Threonine Kinases metabolism, Thromboplastin genetics, Tumor Burden drug effects, Xenograft Model Antitumor Assays, Antineoplastic Agents pharmacology, Cell Proliferation drug effects, Neuroendocrine Tumors drug therapy, Pancreatic Neoplasms drug therapy, Protein Kinase Inhibitors pharmacology, Pyrazoles pharmacology, Pyrimidines pharmacology, TOR Serine-Threonine Kinases antagonists & inhibitors, Thromboplastin metabolism
- Abstract
Essentials Tissue factor (TF) isoforms are expressed in pancreatic neuroendocrine tumors (pNET). TF knockdown inhibits proliferation of human pNET cells in vitro. mTOR kinase inhibitor sapanisertib/MLN0128 suppresses TF expression in human pNET cells. Sapanisertib suppresses TF expression and activity and reduces the growth of pNET tumors in vivo. SUMMARY: Background Full-length tissue factor (flTF) and alternatively spliced TF (asTF) contribute to growth and spread of pancreatic ductal adenocarcinoma. It is unknown, however, if flTF and/or asTF contribute to the pathobiology of pancreatic neuroendocrine tumors (pNETs). Objective To assess TF expression in pNETs and the effects of mTOR complex 1/2 (mTORC1/2) inhibition on pNET growth. Methods Human pNET specimens were immunostained for TF. Human pNET cell lines QGP1 and BON were evaluated for TF expression and responsiveness to mTOR inhibition. shRNA were used to knock down TF in BON. TF cofactor activity was assessed using a two-step FXa generation assay. TF promoter activity was assessed using transient transfection of human TF promoter-driven reporter constructs into cells. Mice bearing orthotopic BON tumors were treated with the mTORC1/2 ATP site competitive inhibitor sapanisertib/MLN0128 (3 mg kg
-1 , oral gavage) for 34 days. Results Immunostaining of pNET tissue revealed flTF and asTF expression. BON and QGP1 expressed both TF isoforms, with BON exhibiting higher levels. shRNA directed against TF suppressed BON proliferation in vitro. Treatment of BON with sapanisertib inhibited mTOR signaling and suppressed TF levels. BON tumors grown in mice treated with sapanisertib had significantly less TF protein and cofactor activity, and were smaller compared with tumors grown in control mice. Conclusions TF isoforms are expressed in pNETs. Sapanisertib suppresses TF mRNA and protein expression as well as TF cofactor activity in vitro and in vivo. Thus, further studies are warranted to evaluate the clinical utility of TF-suppressing mTORC1/2 inhibitor sapanisertib in pNET management., (© 2018 International Society on Thrombosis and Haemostasis.)- Published
- 2019
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30. Polyarticular arthropathy and encephalopathy in a 70-year-old woman.
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Lewis CS, Skiba R, and Gabbay E
- Subjects
- Aged, Arthritis, Gouty pathology, Female, Fever etiology, Humans, Knee Joint pathology, Arthritis, Gouty complications, Brain Diseases etiology
- Abstract
A 70-year-old woman with a background of portopulmonary hypertension, managed with sildenafil and oral diuretics, and cirrhosis, presented with acute on chronic haemorrhoidal bleeding, iron deficiency anaemia and worsening right heart failure. She presented in a normal conscious and cognitive state. Management involved intravenous diuresis with frusemide and blood transfusion. She quickly begun to develop fever, severe polyarticular arthropathy and progressive encephalopathy. Analgesia was started and antibiotics administered for potential septic sources. Extensive investigations, including full septic screen and neurological imaging, revealed no explainable aetiology for her precipitous decline. She continued to have febrile episodes, worsening polyarticular arthropathy and progressive encephalopathy eventually becoming unresponsive. Given the severe polyarticular arthropathy knee aspiration was performed. Urate crystals were identified and intravenous hydrocortisone and colchicine were started. Within 2 days she achieved full resolution of her systemic, musculoskeletal and neurological symptoms. We propose this as a rare case of gout-induced encephalopathy., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2018
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31. Alternatively spliced tissue factor levels are elevated in the plasma of patients with chronic liver diseases.
- Author
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Caversaccio NI, Reina Caro MD, Prince R, Müller M, Lewis CS, Bogdanov VY, Dufour JF, and Angelillo-Scherrer A
- Subjects
- Adult, Biomarkers blood, Carcinoma, Hepatocellular blood, Carcinoma, Hepatocellular genetics, Carcinoma, Hepatocellular therapy, Chronic Disease, Female, Humans, Liver Cirrhosis blood, Liver Cirrhosis genetics, Liver Diseases genetics, Liver Neoplasms blood, Liver Neoplasms genetics, Liver Neoplasms therapy, Male, Middle Aged, Retrospective Studies, Severity of Illness Index, Alternative Splicing, Liver Diseases blood, Thromboplastin analysis, Thromboplastin genetics
- Abstract
Objectives: In patients with chronic liver diseases, hypercoagulability can contribute to the progression of fibrosis and complications of cirrhosis. Tissue factor (TF) is a transmembrane glycoprotein that initiates the extrinsic pathway of blood coagulation. Recent investigations have established that TF is elevated in patients with pancreatic cancer, blood disorders, diabetes, and cardiovascular disease. Alternatively spliced tissue factor (asTF), a secreted form of TF, induces angiogenesis and exhibits low-level procoagulant activity. The aim of this study was to investigate whether the circulating levels of asTF are elevated in the plasma of patients with liver disease., Materials and Methods: In a single-center study, we retrospectively analyzed asTF plasma levels in healthy participants and patients having stage F0-F3 liver fibrosis, liver cirrhosis, as well as hepatocellular carcinoma (HCC). AsTF plasma levels were measured using a sandwich enzyme-linked immunosorbent assay. Values were expressed as median with interquartile range (IQR)., Results: The lowest median plasma asTF concentration (94 pg/ml, IQR: 33-275) was found in the healthy control group. The patients with low-grade liver fibrosis (F0-F1 group) displayed the highest median asTF concentration (404 pg/ml, IQR: 277-789). Significant differences between the asTF levels in the plasma of healthy participants and those in patients with grade F0-F1 fibrosis (P<0.001), patients with grade F2-F3 fibrosis (P=0.019), patients with cirrhosis (P=0.004), and patients with HCC (P<0.001) were found using a Wilcoxon rank-sum test. Treatment-naive patients with HCC had significantly higher asTF levels (P=0.018) than those receiving treatment. AsTF levels were found to increase with worsening Child-Pugh scores and heightened liver disease activity., Conclusion: AsTF levels are elevated in patients with chronic liver diseases, which increase with worsening Child-Pugh scores and decrease following HCC therapy.
- Published
- 2018
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32. Effects of Transient Exposure to High Shear on Neutrophil Rolling Behavior.
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Lewis CS, Alsmadi NZ, Snyder TA, and Schmidtke DW
- Abstract
Introduction: Neutrophils display an array of behaviors ranging from rolling and migration to phagocytosis and granule secretion. Several of these behaviors are modulated by the local shear conditions. In the normal circulation, neutrophils experience shear rates from approximately 10-2,000 s
-1 . However, neutrophils are also exposed to pathological shear levels in natural conditions such as severe stenosis and arteriosclerosis, as well as in blood-contacting devices such as ventricular assist devices (VADs) and hemodialysis machines. The effects of transiently (< 1 sec) exposing neutrophils to abnormally high shear rates (>3,000 s-1 ) are not well understood., Methods: We developed a set of microfluidic devices capable of exposing neutrophils to high shear rates for short durations (100-400 msec). Suspensions of isolated neutrophils were perfused through the devices and their rolling velocities on P-selectin were analyzed before and after shear exposure., Results: We observed a significant increase in neutrophil rolling velocities on P-selectin coated regions following transient high shear exposure. The magnitude of the rolling velocity increase was dependent upon the duration of high shear exposure and became statistically significant for exposure times of 310 msec or longer. When polystyrene beads coated with a glycosulfopeptide that mimics the binding region of P-selectin glycoprotein ligand-1 (PSGL-1) were perfused through the devices, no change between the pre-shear and post-shear rolling velocities was observed., Conclusions: These results suggest that high shear levels alter normal neutrophil rolling behavior and are important for understanding neutrophil biology in high shear conditions, as well as for improving medical device performance., Competing Interests: CONFLICT OF INTEREST Trevor A. Snyder is an employee of VADovations Inc. C. S. Lewis, N. Z. Alsmadi, and D. W. Schmidtke have no conflict of interest to declare.- Published
- 2018
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33. Feasibility of a Fourth Ventriculopleural Shunt for Diversion of an Isolated Fourth Ventricle: A Technical Note.
- Author
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Lewis CS, Chang KE, Bakhsheshian J, Strickland BA, and Pham MH
- Abstract
Isolated fourth ventricle syndrome is an uncommon entity due to obstruction of both inlet and outflow foramina. The resulting mass effect from the progressively expanding fourth ventricle may cause symptoms from both cerebellar and brainstem compression. Although a variety of treatment modalities have been advocated for this condition, an in-depth description of placement of a fourth ventriculopleural (VPL) shunt from a single-stage prone approach has not yet been published in the literature. We describe here a case of successful placement of a fourth VPL shunt in a 22-year-old female with a history of a prior posterior fossa pilocytic astrocytoma resection who presented with symptomatic isolated fourth ventricular hydrocephalus., Competing Interests: There are no conflicts of interest.
- Published
- 2018
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34. Divergent roles for antigenic drive in the aetiology of primary versus dasatinib-associated CD8 + TCR-Vβ + expansions.
- Author
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Lissina A, McLaren JE, Ilander M, Andersson EI, Lewis CS, Clement M, Herman A, Ladell K, Llewellyn-Lacey S, Miners KL, Gostick E, Melenhorst JJ, Barrett AJ, Price DA, Mustjoki S, and Wooldridge L
- Subjects
- Adult, Aged, Antineoplastic Agents therapeutic use, CD8-Positive T-Lymphocytes cytology, Clone Cells, Dasatinib therapeutic use, Female, Humans, Male, Middle Aged, Phenotype, Antineoplastic Agents adverse effects, CD8-Positive T-Lymphocytes immunology, Dasatinib adverse effects, Leukemia, Large Granular Lymphocytic drug therapy, Leukemia, Large Granular Lymphocytic immunology, Leukemia, Myeloid, Chronic-Phase drug therapy, Leukemia, Myeloid, Chronic-Phase immunology, Receptors, Antigen, T-Cell, alpha-beta immunology
- Abstract
CD8
+ T-cell expansions are the primary manifestation of T-cell large granular lymphocytic leukemia (T-LGLL), which is frequently accompanied by neutropenia and rheumatoid arthritis, and also occur as a secondary phenomenon in leukemia patients treated with dasatinib, notably in association with various drug-induced side-effects. However, the mechanisms that underlie the genesis and maintenance of expanded CD8+ T-cell receptor (TCR)-Vβ+ populations in these patient groups have yet to be fully defined. In this study, we performed a comprehensive phenotypic and clonotypic assessment of expanded (TCR-Vβ+ ) and residual (TCR-Vβ- ) CD8+ T-cell populations in T-LGLL and dasatinib-treated chronic myelogenous leukemia (CML) patients. The dominant CD8+ TCR-Vβ+ expansions in T-LGLL patients were largely monoclonal and highly differentiated, whereas the dominant CD8+ TCR-Vβ+ expansions in dasatinib-treated CML patients were oligoclonal or polyclonal, and displayed a broad range of memory phenotypes. These contrasting features suggest divergent roles for antigenic drive in the immunopathogenesis of primary versus dasatinib-associated CD8+ TCR-Vβ+ expansions.- Published
- 2018
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35. Targeting Sphingosine Kinases for the Treatment of Cancer.
- Author
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Lewis CS, Voelkel-Johnson C, and Smith CD
- Subjects
- Animals, Humans, Neoplasms pathology, Antineoplastic Agents therapeutic use, Molecular Targeted Therapy, Neoplasms drug therapy, Neoplasms enzymology, Phosphotransferases (Alcohol Group Acceptor) antagonists & inhibitors
- Abstract
Sphingosine kinases (SK1 and SK2) are key, druggable targets within the sphingolipid metabolism pathway that promote tumor growth and pathologic inflammation. A variety of isozyme-selective and dual inhibitors of SK1 and SK2 have been described in the literature, and at least one compound has reached clinical testing in cancer patients. In this chapter, we will review the rationale for targeting SKs and summarize the preclinical and emerging clinical data for ABC294640 as the first-in-class selective inhibitor of SK2., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
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36. Constricted microfluidic devices to study the effects of transient high shear exposure on platelets.
- Author
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Alsmadi NZ, Shapiro SJ, Lewis CS, Sheth VM, Snyder TA, and Schmidtke DW
- Abstract
Due to the critical roles that platelets play in thrombosis during many biological and pathological events, altered platelet function may be a key contributor to altered hemostasis, leading to both thrombotic and hemorrhagic complications. Platelet adhesion at arterial shear rates occurs through binding to von Willebrand Factor via the glycoprotein (GP) GPIb receptor. GPIb binding can induce platelet activation distinguishable by P-selectin (CD62P) surface expression and α
IIb β3 activation, resulting in platelet aggregation and formation of the primary hemostatic plug to stop bleeding. Previous studies have used cone and plate viscometers to examine pathologic blood flow conditions, applied shear rates that are relatively low, and examined exposure times that are orders of magnitude longer compared to conditions present in ventricular assist devices, mechanical heart valves, or pathologic states such as stenotic arteries. Here, we evaluate the effect of short exposure to high shear on granule release and receptor shedding utilizing a constricted microfluidic device in conjunction with flow cytometry and enzyme-linked immunosorbent assay. In this study, platelets were first perfused through microfluidic channels capable of producing shear rates of 80 000-100 000 s-1 for exposure times of 0-73 ms. We investigated platelet activation by measuring the expression level of CD62P (soluble and surface expressed), platelet factor 4 (PF4), and beta-thromboglobulin (βTG). In addition, we measured potential platelet receptor shedding of GPVI and GPIb using flow cytometry. The results showed that a single pass to high shear with short exposure times (milliseconds) had no effect on the levels of CD62P, GPVI and GPIb, or on the release of alpha granule content (PF4, βTG, and sP-selectin).- Published
- 2017
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37. Synthesis-driven, structure-dependent optical behavior in phase-tunable NaYF 4 :Yb,Er-based motifs and associated heterostructures.
- Author
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Liu H, Han J, McBean C, Lewis CS, Kumar Routh P, Cotlet M, and Wong SS
- Abstract
Understanding the key parameters necessary for generating uniform Er,Yb co-activated NaYF
4 possessing various selected phases (i.e. cubic or hexagonal) represents an important chemical strategy towards tailoring optical behavior in these systems. Herein, we report on a straightforward hydrothermal synthesis in which the separate effects of reaction temperature, reaction time, and precursor stoichiometry in the absence of any surfactant were independently investigated. Interestingly, the presence and the concentration of NH4 OH appear to be the most critical determinants of the phase and morphology. For example, with NH4 OH as an additive, we have observed the formation of novel hierarchical nanowire bundles which possess overall lengths of ∼5 μm and widths of ∼1.5 μm but are composed of constituent component sub-units of long, ultrathin (∼5 nm) nanowires. These motifs have yet to be reported as distinctive morphological manifestations of fluoride materials. The optical properties of as-generated structures have also been carefully analyzed. Specifically, we have observed tunable, structure-dependent energy transfer behavior associated with the formation of a unique class of NaYF4 -CdSe quantum dot (QD) heterostructures, incorporating zero-dimensional (0D), one-dimensional (1D), and three-dimensional (3D) NaYF4 structures. Our results have demonstrated the key roles of the intrinsic morphology-specific physical surface area and porosity as factors in governing the resulting opto-electronic behavior. Specifically, the trend in energy transfer efficiency correlates well with the corresponding QD loading within these heterostructures, thereby implying that the efficiency of FRET appears to be directly affected by the amount of QDs immobilized onto the external surfaces of the underlying fluoride host materials.- Published
- 2017
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38. Activation of carbonic anhydrase IX by alternatively spliced tissue factor under late-stage tumor conditions.
- Author
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Ramchandani D, Unruh D, Lewis CS, Bogdanov VY, and Weber GF
- Subjects
- Animals, Antigens, Neoplasm chemistry, Antigens, Neoplasm genetics, Antineoplastic Agents pharmacology, Antineoplastic Agents therapeutic use, Apoenzymes genetics, Carbonic Anhydrase IX antagonists & inhibitors, Carbonic Anhydrase IX chemistry, Carbonic Anhydrase IX genetics, Carbonic Anhydrase Inhibitors pharmacology, Carbonic Anhydrase Inhibitors therapeutic use, Carcinoma, Pancreatic Ductal drug therapy, Carcinoma, Pancreatic Ductal pathology, Cell Line, Tumor, Cell Movement drug effects, Cell Proliferation drug effects, Enzyme Induction drug effects, G2 Phase drug effects, Humans, Mice, Nude, Neoplasm Proteins agonists, Neoplasm Proteins antagonists & inhibitors, Neoplasm Proteins genetics, Neoplasm Staging, Pancreatic Neoplasms drug therapy, Pancreatic Neoplasms pathology, Phenylurea Compounds pharmacology, Phenylurea Compounds therapeutic use, Recombinant Proteins metabolism, Sulfonamides pharmacology, Sulfonamides therapeutic use, Thromboplastin genetics, Tumor Hypoxia, Xenograft Model Antitumor Assays, Alternative Splicing drug effects, Antigens, Neoplasm metabolism, Apoenzymes metabolism, Carbonic Anhydrase IX metabolism, Carcinoma, Pancreatic Ductal metabolism, Neoplasm Proteins metabolism, Pancreatic Neoplasms metabolism, Thromboplastin metabolism
- Abstract
Molecules of the coagulation pathway predispose patients to cancer-associated thrombosis and also trigger intracellular signaling pathways that promote cancer progression. The primary transcript of tissue factor, the main physiologic trigger of blood clotting, can undergo alternative splicing yielding a secreted variant, termed asTF (alternatively spliced tissue factor). asTF is not required for normal hemostasis, but its expression levels positively correlate with advanced tumor stages in several cancers, including pancreatic adenocarcinoma. The asTF-overexpressing pancreatic ductal adenocarcinoma cell line Pt45.P1/asTF+ and its parent cell line Pt45.P1 were tested for growth and mobility under normoxic conditions that model early-stage tumors, and in the hypoxic environment of late-stage cancers. asTF overexpression in Pt45.P1 cells conveys increased proliferative ability. According to cell cycle analysis, the major fraction of Pt45.P1/asTF+ cells reside in the dividing G
2 /M phase of the cell cycle, whereas the parental Pt45.P1 cells are mostly confined to the quiescent G0 /G1 phase. asTF overexpression is also associated with significantly higher mobility in cells plated under either normoxia or hypoxia. A hypoxic environment leads to upregulation of carbonic anhydrase IX (CAIX), which is more pronounced in Pt45.P1/asTF+ cells. Inhibition of CAIX by the compound U-104 significantly decreases cell growth and mobility of Pt45.P1/asTF+ cells in hypoxia, but not in normoxia. U-104 also reduces the growth of Pt45.P1/asTF+ orthotopic tumors in nude mice. CAIX is a novel downstream mediator of asTF in pancreatic cancer, particularly under hypoxic conditions that model late-stage tumor microenvironment., Competing Interests: The authors disclose no potential conflicts of interest- Published
- 2016
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39. Suppression of c-Myc and RRM2 expression in pancreatic cancer cells by the sphingosine kinase-2 inhibitor ABC294640.
- Author
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Lewis CS, Voelkel-Johnson C, and Smith CD
- Subjects
- Acetylation drug effects, Adamantane pharmacology, Antimetabolites, Antineoplastic pharmacology, Cell Line, Tumor, Cell Survival drug effects, Cell Survival genetics, Deoxycytidine analogs & derivatives, Deoxycytidine pharmacology, Drug Synergism, Gene Expression Regulation, Neoplastic drug effects, Histones metabolism, Humans, Pancreatic Neoplasms genetics, Pancreatic Neoplasms metabolism, Pancreatic Neoplasms pathology, Phosphorylation drug effects, Phosphotransferases (Alcohol Group Acceptor) metabolism, Proto-Oncogene Proteins c-myc genetics, Retinoblastoma Protein metabolism, Ribonucleoside Diphosphate Reductase genetics, Gemcitabine, Adamantane analogs & derivatives, Phosphotransferases (Alcohol Group Acceptor) antagonists & inhibitors, Proto-Oncogene Proteins c-myc metabolism, Pyridines pharmacology, Ribonucleoside Diphosphate Reductase metabolism
- Abstract
Pancreatic cancer remains extremely difficult to treat, with the average lifespan following diagnosis being only 3-6 months, resulting in a death to incidence ratio of 0.94. A major reason for this high mortality rate is resistance to the main chemotherapeutic agent used to treat this disease, gemcitabine. Alterations in nucleoside and gemcitabine metabolism, specifically over-expression of ribonucleotide reductase, have been implicated as a major mechanism of resistance to this drug. Here, we show that inhibition of sphingosine kinase-2 by the specific inhibitor ABC294640 is synergistically cytotoxic with gemcitabine toward three human pancreatic cancer cell lines. Treatment with ABC294640 results in decreased expression of both RRM2 and MYC in all three cell lines. Additionally, expression of c-Myc protein and phosphorylation of Rb at S780 both decrease in a dose-dependent manner in response to ABC294640, while acetylation of H3-K9 and p21 levels increase. Pretreatment with the protein phosphatase 1 inhibitor okadaic acid or the ceramide synthase inhibitor fumonisin B1 fails to prevent the effects of ABC294640 on Rb phosphorylation. These data indicate a role for sphingosine kinase-2 in E2F and c-Myc mediated transcription through alteration of histone acetylation and p21 expression. These effects of ABC294640 suggest that it may be an effective agent for pancreatic cancer, particularly in combination with gemcitabine.
- Published
- 2016
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40. Comparison of safety between 1-stage and 2-stage surgery: from laparoscopic adjustable gastric banding to laparoscopic sleeve gastrectomy.
- Author
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Lewis CS, Varma AK, and Hamdorf JM
- Subjects
- Aged, Body Mass Index, Female, Gastrectomy methods, Gastroesophageal Reflux etiology, Gastroesophageal Reflux surgery, Gastroplasty methods, Humans, Laparoscopy methods, Male, Middle Aged, Obesity surgery, Overweight surgery, Postoperative Complications etiology, Prospective Studies, Reoperation, Tissue Adhesions etiology, Treatment Outcome, Weight Loss physiology, Gastrectomy adverse effects, Gastroplasty adverse effects, Laparoscopy adverse effects
- Abstract
Background: Laparoscopic sleeve gastrectomy (LSG) is becoming increasingly popular. With significant failure rates for laparoscopic adjustable gastric banding (LAGB), conversion to LSG is an attractive consideration for maintenance of target percentage excess weight loss (%EWL). Conversions can be successfully achieved in either 1-stage (OS) or 2-stage (TS) surgery., Objectives: We intend to examine safety between OS and TS surgery and determine features indicative for OS surgery., Setting: Records were audited from the database of a private surgical practice located in Perth, Western Australia., Methods: We analyzed 86 patients in a prospective observational study over a 3-year time frame (38 OS, 48 TS). The primary outcome was perioperative events, graded using the Clavien-Dindo classification system. Secondary outcomes included any preoperative, intraoperative, and postoperative events., Results: Surgical complications were similar between OS and TS groups. Grades of complications were not significantly different. No difference was found in procedural normality between cohorts (P = .95). More adhesions were present in the TS group compared with the OS group after accounting for adjustments (P = .05). Patient demographic characteristics were not different between groups, with the exception of body mass index (BMI). There were no staple line leaks within the OS group; 2 leaks occurred in the TS group., Conclusion: OS surgery appears as safe as TS surgery provided surgeons carefully assess patient eligibility. We recommend the following features for ideal OS candidacy: no previous band complications, minimal peritoneal adhesions under laparoscopy, minimal co-morbidities, and a lower BMI at entry into conversion., (Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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41. Antibody-based targeting of alternatively spliced tissue factor: a new approach to impede the primary growth and spread of pancreatic ductal adenocarcinoma.
- Author
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Unruh D, Ünlü B, Lewis CS, Qi X, Chu Z, Sturm R, Keil R, Ahmad SA, Sovershaev T, Adam M, Van Dreden P, Woodhams BJ, Ramchandani D, Weber GF, Rak JW, Wolberg AS, Mackman N, Versteeg HH, and Bogdanov VY
- Subjects
- Alternative Splicing, Animals, Antibodies, Monoclonal pharmacology, Cell Line, Tumor, Cell Movement drug effects, Humans, Mice, Mice, Nude, Antineoplastic Agents pharmacology, Carcinoma, Pancreatic Ductal pathology, Pancreatic Neoplasms pathology, Thromboplastin antagonists & inhibitors
- Abstract
Alternatively spliced Tissue Factor (asTF) is a secreted form of Tissue Factor (TF), the trigger of blood coagulation whose expression levels are heightened in several forms of solid cancer, including pancreatic ductal adenocarcinoma (PDAC). asTF binds to β1 integrins on PDAC cells, whereby it promotes tumor growth, metastatic spread, and monocyte recruitment to the stroma. In this study, we determined if targeting asTF in PDAC would significantly impact tumor progression. We here report that a novel inhibitory anti-asTF monoclonal antibody curtails experimental PDAC progression. Moreover, we show that tumor-derived asTF is able to promote PDAC primary growth and spread during early as well as later stages of the disease. This raises the likelihood that asTF may comprise a viable target in early- and late-stage PDAC. In addition, we show that TF expressed by host cells plays a significant role in PDAC spread. Together, our data demonstrate that targeting asTF in PDAC is a novel strategy to stem PDAC progression and spread., Competing Interests: The authors disclose no potential conflicts of interest.
- Published
- 2016
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42. Absence of Cytotoxicity towards Microglia of Iron Oxide (α-Fe 2 O 3 ) Nanorhombohedra.
- Author
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Lewis CS, Torres L, Miyauchi JT, Rastegar C, Patete JM, Smith JM, Wong SS, and Tsirka SE
- Abstract
Understanding the nature of interactions between nanomaterials, such as commercially ubiquitous hematite (α-Fe
2 O3 ) Nanorhombohedra (N-Rhomb) and biological systems is of critical importance for gaining insight into the practical applicability of nanomaterials. Microglia represent the first line of defense in the central nervous system (CNS) during severe injury or disease such as Parkinson's and Alzheimer's disease as illustrative examples. Hence, to analyze the potential cytotoxic effect of nanorhombohedra exposure in the presence of microglia, we have synthesized Rhodamine B (RhB) labeled-α-Fe2 O3 N-Rhomb, with lengths of 47 ± 10 nm and widths of 35 ± 8 nm. Internalization of RhB labeled-α-Fe2 O3 N-Rhomb by microglia in the mouse brain was observed, and a dose-dependent increase in the cellular iron content as probed by cellular fluorescence was detected in cultured microglia after nanoparticle exposure. The cells maintained clear functional viability, exhibiting little to no cytotoxic effects after 24 and 48 hours at acceptable, physiological concentrations. Importantly, the nanoparticle exposure did not induce microglial cells to produce either tumor necrosis factor alpha (TNFα) or interleukin 1-beta (IL1β), two pro-inflammatory cytokines, nor did exposure induce the production of nitrites and reactive oxygen species (ROS), which are common indicators for the onset of inflammation. Finally, we propose that under the conditions of our experiments, i.e. in the presence of RhB labeled-α-Fe2 O3 N-Rhomb maintaining concentrations of up to 100 µg/mL after 48 hours of incubation, the in vitro and in vivo internalization of RhB labeled-α-Fe2 O3 N-Rhomb are likely to be clathrin-dependent, which represents a conventional mechanistic uptake route for most cells. Given the crucial role that microglia play in many neurological disorders, understanding the potential cytotoxic effects of these nanostructures is of fundamental importance if they are to be used in a therapeutic setting.- Published
- 2016
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- View/download PDF
43. Effects of shear on P-selectin deposition in microfluidic channels.
- Author
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Shimp EA, Alsmadi NZ, Cheng T, Lam KH, Lewis CS, and Schmidtke DW
- Abstract
Traditional leukocyte adhesion assays have provided significant insight into the mechanisms of leukocyte rolling in part through the use of homogeneously coated surfaces. These assays typically involve protein coating of glass coverslips or plastic petri dishes applied via a static drop of protein solution. With this approach, it is difficult to spatially control the location of proteins to fabricate surface-bound protein gradients that mimic in vivo situations. Microfluidic patterning of proteins with microfluidic devices has become a popular technique due to the ability to spatially pattern proteins on a cellular scale. Despite the advantages of microfluidic patterning, few studies have systematically investigated the effects of perfusion time, protein concentration, and perfusion shear stress on protein deposition. Herein, we demonstrated the fabrication of both line and step gradients of P-selectin on glass substrates that support cell rolling and adhesion assays. Investigation of the flow conditions during the microfluidic patterning led to several significant findings. We observed that the protein deposition time of 5 min was sufficient to deposit adequate P-selectin to support neutrophil rolling. We demonstrated that the amount of membrane P-selectin (mP-selectin) or recombinant P-selectin (rP-selectin) deposited showed a dependence on the perfusion shear stress between 4.0 and 32.0 dyn/cm(2), while similar studies with fibronectin or fibrinogen showed no shear stress dependence. Finally, we also created step changes in surface adherent protein concentration of P-selectin to characterize leukocyte-rolling behavior in response to sudden changes in ligand density.
- Published
- 2016
- Full Text
- View/download PDF
44. Probing charge transfer in a novel class of luminescent perovskite-based heterostructures composed of quantum dots bound to RE-activated CaTiO3 phosphors.
- Author
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Lewis CS, Liu H, Han J, Wang L, Yue S, Brennan NA, and Wong SS
- Abstract
We report on the synthesis and structural characterization of novel semiconducting heterostructures composed of cadmium selenide (CdSe) quantum dots (QDs) attached onto the surfaces of novel high-surface area, porous rare-earth-ion doped alkaline earth titanate micron-scale spherical motifs, i.e. both Eu-doped and Pr-doped CaTiO3, composed of constituent, component nanoparticles. These unique metal oxide perovskite building blocks were created by a multi-pronged synthetic strategy involving molten salt and hydrothermal protocols. Subsequently, optical characterization of these heterostructures indicated a clear behavioral dependence of charge transfer in these systems upon a number of parameters such as the nature of the dopant, the reaction temperature, and particle size. Specifically, 2.7 nm diameter ligand-functionalized CdSe QDs were anchored onto sub-micron sized CaTiO3-based spherical assemblies, prepared by molten salt protocols. We found that both the Pr- and Eu-doped CaTiO3 displayed pronounced PL emissions, with maximum intensities observed using optimized lanthanide concentrations of 0.2 mol% and 6 mol%, respectively. Analogous experiments were performed on Eu-doped BaTiO3 and SrTiO3 motifs, but CaTiO3 still performed as the most effective host material amongst the three perovskite systems tested. Moreover, the ligand-capped CdSe QD-doped CaTiO3 heterostructures exhibited effective charge transfer between the two individual constituent nanoscale components, an assertion corroborated by the corresponding quenching of their measured PL signals.
- Published
- 2016
- Full Text
- View/download PDF
45. Genotyping coronaviruses associated with feline infectious peritonitis.
- Author
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Lewis CS, Porter E, Matthews D, Kipar A, Tasker S, Helps CR, and Siddell SG
- Subjects
- Animals, Cats, Cluster Analysis, Coronavirus, Feline isolation & purification, Gene Order, Genes, Viral, Genome, Viral, Genotype, Molecular Sequence Data, Phylogeny, RNA, Viral genetics, Sequence Analysis, DNA, Sequence Homology, United Kingdom, Coronavirus, Feline classification, Coronavirus, Feline genetics, Feline Infectious Peritonitis virology, Genetic Variation
- Abstract
Feline coronavirus (FCoV) infections are endemic among cats worldwide. The majority of infections are asymptomatic or result in only mild enteric disease. However, approximately 5 % of cases develop feline infectious peritonitis (FIP), a systemic disease that is a frequent cause of death in young cats. In this study, we report the complete coding genome sequences of six FCoVs: three from faecal samples from healthy cats and three from tissue lesion samples from cats with confirmed FIP. The six samples were obtained over a period of 8 weeks at a single-site cat rescue and rehoming centre in the UK. We found amino acid differences located at 44 positions across an alignment of the six virus translatomes and, at 21 of these positions, the differences fully or partially discriminated between the genomes derived from the faecal samples and the genomes derived from the tissue lesion samples. In this study, two amino acid differences fully discriminated the two classes of genomes: these were both located in the S2 domain of the virus surface glycoprotein gene. We also identified deletions in the 3c protein ORF of genomes from two of the FIP samples. Our results support previous studies that implicate S protein mutations in the pathogenesis of FIP., (© 2015 The Authors.)
- Published
- 2015
- Full Text
- View/download PDF
46. LCL124, a cationic analog of ceramide, selectively induces pancreatic cancer cell death by accumulating in mitochondria.
- Author
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Beckham TH, Lu P, Jones EE, Marrison T, Lewis CS, Cheng JC, Ramshesh VK, Beeson G, Beeson CC, Drake RR, Bielawska A, Bielawski J, Szulc ZM, Ogretmen B, Norris JS, and Liu X
- Subjects
- Animals, Antimetabolites, Antineoplastic pharmacology, Apoptosis drug effects, Benzimidazoles, Blotting, Western, Carbocyanines, Cell Line, Tumor, Ceramides metabolism, Chromatography, High Pressure Liquid, Coloring Agents, Cytochromes c metabolism, Deoxycytidine analogs & derivatives, Deoxycytidine pharmacology, Female, Membrane Potential, Mitochondrial drug effects, Mice, Mice, Nude, Oxygen Consumption drug effects, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Spectrum Analysis, Xenograft Model Antitumor Assays, Gemcitabine, Antineoplastic Agents pharmacology, Cell Death drug effects, Ceramides pharmacology, Mitochondria metabolism, Pancreatic Neoplasms pathology
- Abstract
Treatment of pancreatic cancer that cannot be surgically resected currently relies on minimally beneficial cytotoxic chemotherapy with gemcitabine. As the fourth leading cause of cancer-related death in the United States with dismal survival statistics, pancreatic cancer demands new and more effective treatment approaches. Resistance to gemcitabine is nearly universal and appears to involve defects in the intrinsic/mitochondrial apoptotic pathway. The bioactive sphingolipid ceramide is a critical mediator of apoptosis initiated by a number of therapeutic modalities. It is noteworthy that insufficient ceramide accumulation has been linked to gemcitabine resistance in multiple cancer types, including pancreatic cancer. Taking advantage of the fact that cancer cells frequently have more negatively charged mitochondria, we investigated a means to circumvent resistance to gemcitabine by targeting delivery of a cationic ceramide (l-t-C6-CCPS [LCL124: ((2S,3S,4E)-2-N-[6'-(1″-pyridinium)-hexanoyl-sphingosine bromide)]) to cancer cell mitochondria. LCL124 was effective in initiating apoptosis by causing mitochondrial depolarization in pancreatic cancer cells but demonstrated significantly less activity against nonmalignant pancreatic ductal epithelial cells. Furthermore, we demonstrate that the mitochondrial membrane potentials of the cancer cells were more negative than nonmalignant cells and that dissipation of this potential abrogated cell killing by LCL124, establishing that the effectiveness of this compound is potential-dependent. LCL124 selectively accumulated in and inhibited the growth of xenografts in vivo, confirming the tumor selectivity and therapeutic potential of cationic ceramides in pancreatic cancer. It is noteworthy that gemcitabine-resistant pancreatic cancer cells became more sensitive to subsequent treatment with LCL124, suggesting that this compound may be a uniquely suited to overcome gemcitabine resistance in pancreatic cancer.
- Published
- 2013
- Full Text
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47. Functional reconstitution of human eukaryotic translation initiation factor 3 (eIF3).
- Author
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Sun C, Todorovic A, Querol-Audí J, Bai Y, Villa N, Snyder M, Ashchyan J, Lewis CS, Hartland A, Gradia S, Fraser CS, Doudna JA, Nogales E, and Cate JH
- Subjects
- COP9 Signalosome Complex, DNA, Complementary metabolism, Escherichia coli metabolism, HeLa Cells, Hepacivirus genetics, Hepacivirus metabolism, Humans, Microscopy, Electron methods, Models, Molecular, Molecular Conformation, Multiprotein Complexes chemistry, Peptide Hydrolases chemistry, Protein Binding, Protein Biosynthesis, Protein Structure, Tertiary, RNA, Messenger metabolism, Ribosomes chemistry, Eukaryotic Initiation Factor-3 chemistry
- Abstract
Protein fate in higher eukaryotes is controlled by three complexes that share conserved architectural elements: the proteasome, COP9 signalosome, and eukaryotic translation initiation factor 3 (eIF3). Here we reconstitute the 13-subunit human eIF3 in Escherichia coli, revealing its structural core to be the eight subunits with conserved orthologues in the proteasome lid complex and COP9 signalosome. This structural core in eIF3 binds to the small (40S) ribosomal subunit, to translation initiation factors involved in mRNA cap-dependent initiation, and to the hepatitis C viral (HCV) internal ribosome entry site (IRES) RNA. Addition of the remaining eIF3 subunits enables reconstituted eIF3 to assemble intact initiation complexes with the HCV IRES. Negative-stain EM reconstructions of reconstituted eIF3 further reveal how the approximately 400 kDa molecular mass structural core organizes the highly flexible 800 kDa molecular mass eIF3 complex, and mediates translation initiation.
- Published
- 2011
- Full Text
- View/download PDF
48. Local antibiotic delivery with bovine cancellous chips.
- Author
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Lewis CS, Katz J, Baker MI, Supronowicz PR, Gill E, and Cobb RR
- Subjects
- Alkaline Phosphatase metabolism, Animals, Anti-Bacterial Agents pharmacokinetics, Biocompatible Materials, Bone Transplantation, Cattle, Cell Adhesion drug effects, Cell Proliferation, Delayed-Action Preparations, Gentamicins administration & dosage, Gentamicins pharmacokinetics, In Vitro Techniques, Materials Testing, Osteoblasts cytology, Osteoblasts drug effects, Osteomyelitis enzymology, Osteomyelitis microbiology, Osteomyelitis pathology, Rats, Staphylococcal Infections drug therapy, Staphylococcus aureus drug effects, Staphylococcus aureus growth & development, Transplantation, Heterologous, Anti-Bacterial Agents administration & dosage, Drug Delivery Systems, Osteomyelitis drug therapy
- Abstract
Infected bone defects and osteomyelitis are encountered frequently in trauma cases. Currently, the standard of care for osteomyelitis cases is prolonged systemic antibiotic therapy and implantation of antibiotic carrier beads. However, this method requires a secondary surgery to remove the beads after the infection has cleared. In the present study a common bone void filler was investigated for its ability to be infused with an antibiotic. This study demonstrates that the xenograft material tested can be loaded with gentamicin and release clinically relevant levels of the drug for at least 14 days in vitro allowing for the inhibition of bacterial growth on the graft. This study also demonstrates that the levels of gentamicin released did not have an adverse effect on primary osteoblast cell proliferation or ability to generate alkaline phosphatase. This bone void filler may represent a viable alternative to current methods of local antibiotic delivery in orthopedic applications.
- Published
- 2011
- Full Text
- View/download PDF
49. Osteoconductivity and osteoinductivity of Puros(R) DBM putty.
- Author
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Moore ST, Katz JM, Zhukauskas RM, Hernandez RM, Lewis CS, Supronowicz PR, Gill E, Grover SM, Long NS, and Cobb RR
- Subjects
- Amino Acids analysis, Animals, Bone Matrix chemistry, Cell Line, Cell Proliferation, Cell Survival, Cells, Cultured, Humans, Mice, Osteoblasts cytology, Porosity, Rats, Rats, Nude, Bone Matrix transplantation, Bone Substitutes chemistry, Bone Substitutes therapeutic use, Osteogenesis
- Abstract
Bone graft substitutes have been developed due to the limited supply and morbidity associated with using autogenous graft material. Allogeneic demineralized bone matrix (DBM) has been used extensively as a clinical graft material because of its inherent osteoinductive and osteoconductive properties. Differential enhancement of these properties may optimize the performance of these products for various orthopedic and craniofacial applications. Commercially available bone paste products consist of formulations that combine DBM with a carrier to facilitate handling and containment. In the present study, we present results of a comprehensive in vitro and in vivo characterization of a 100% human DBM putty product, Puros DBM Putty. Results indicate the DBM particles are completely dispersed in the putty. Data are presented showing the porosity of and cell attachment to Puros DBM Putty, thereby demonstrating the osteoconductive properties of this DBM. Puros DBM Putty was also shown to be osteoinductive in the rat ectopic pouch model. We demonstrate here for the first time that Puros DBM Putty maintains its activity to markedly stimulate or induce bone formation over the entire period of its shelf life. Taken together, these data demonstrate that the 100% human allograft derived Puros DBM Putty could be an effective bone graft substitute.
- Published
- 2011
- Full Text
- View/download PDF
50. Antitumor activity of sphingosine kinase 2 inhibitor ABC294640 and sorafenib in hepatocellular carcinoma xenografts.
- Author
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Beljanski V, Lewis CS, and Smith CD
- Subjects
- Adamantane pharmacology, Adamantane therapeutic use, Animals, Antineoplastic Agents pharmacology, Apoptosis drug effects, Benzenesulfonates pharmacology, Blotting, Western, Carcinoma, Hepatocellular metabolism, Carcinoma, Hepatocellular pathology, Flow Cytometry, Hep G2 Cells, Humans, Liver Neoplasms metabolism, Liver Neoplasms pathology, Lysophospholipids blood, Mice, Mitogen-Activated Protein Kinases metabolism, Niacinamide analogs & derivatives, Phenylurea Compounds, Phosphotransferases (Alcohol Group Acceptor) metabolism, Pyridines pharmacology, Sorafenib, Sphingosine analogs & derivatives, Sphingosine blood, Xenograft Model Antitumor Assays, Adamantane analogs & derivatives, Antineoplastic Agents therapeutic use, Benzenesulfonates therapeutic use, Carcinoma, Hepatocellular drug therapy, Liver Neoplasms drug therapy, Phosphotransferases (Alcohol Group Acceptor) antagonists & inhibitors, Pyridines therapeutic use
- Abstract
The balance between the pro-apoptotic lipids ceramide and sphingosine and the pro-survival lipid sphingosine 1-phosphate (S1P) is termed the "sphingosine rheostat". Two isozymes, sphingosine kinase 1 and 2 (SK1 and SK2), are responsible for phosphorylation of pro-apoptotic sphingosine to form pro-survival S1P. We have previously reported the antitumor properties of an SK2 selective inhibitor, ABC294640, alone or in combination with the multikinase inhibitor sorafenib in mouse models of kidney carcinoma and pancreatic adenocarcinoma. Here we evaluated the combined antitumor effects of the aforementioned drug combination in two mouse models of hepatocellular carcinoma. Although combining the SK2 inhibitor, ABC294640, and sorafenib in vitro only afforded additive drug-drug effects, their combined antitumor properties in the mouse model bearing HepG2 cells mirrored effects previously observed in animals bearing kidney carcinoma and pancreatic adenocarcinoma cells. Combining ABC294640 and sorafenib led to a decrease in the levels of phosphorylated ERK in SK-HEP-1 cells, indicating that the antitumor effect of this drug combination is likely mediated through a suppression of the MAPK pathway in hepatocellular models. We also measured levels of S1P in the plasma of mice treated with two different doses of ABC294640 and sorafenib. We found decreases in the levels of S1P in plasma of mice treated daily with 100 mg/kg of ABC294640 for 5 weeks, and this decrease was not affected by co-administration of sorafenib. Taken together, these data support combining ABC294640 and sorafenib in clinical trials in HCC patients. Furthermore, monitoring levels of S1P may provide a pharmacodynamic marker of ABC294640 activity.
- Published
- 2011
- Full Text
- View/download PDF
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