Search

The intricate formation of the palate involves a series of complex events, yet its mechanistic basis remains uncertain. To explore major cell populations in the palate and their roles during development, we constructed a spatiotemporal transcription landscape of palatal cells. Palate samples from C57BL/6 J mice at embryonic days 12.5 (E12.5), 14.5 (E14.5), and 16.5 (E16.5) underwent single-cell RNA sequencing (scRNA-seq) to identify distinct cell subsets. In addition, spatial enhanced resolution omics-sequencing (stereo-seq) was used to characterize the spatial distribution of these subsets. Integrating scRNA-seq and stereo-seq with CellTrek annotated mesenchymal and epithelial cellular components of the palate during development. Furthermore, cellular communication networks between these cell subpopulations were analyzed to discover intercellular signaling during palate development. From the analysis of the middle palate, both mesenchymal and epithelial populations were spatially segregated into 3 domains. The middle palate mesenchymal subpopulations were associated with tooth formation, ossification, and tissue remodeling, with initial state cell populations located proximal to the dental lamina. The nasal epithelium of the palatal shelf exhibited richer humoral immune responses than the oral side. Specific enrichment of Tgfβ3 and Pthlh signals in the midline epithelial seam at E14.5 suggested a role in epithelial–mesenchymal transition. In summary, this study provides high-resolution transcriptomic information, contributing to a deeper mechanistic understanding of palate biology and pathophysiology. [ABSTRACT FROM AUTHOR]

The quest for finding a suitable scaffold system that supports cell survival and function and, ultimately, the regeneration of the pulp–dentin complex remains challenging. Herein, we hypothesized that dental pulp stem cells (DPSCs) encapsulated in a collagen-based hydrogel with varying stiffness would regenerate functional dental pulp and dentin when concentrically injected into the tooth slices. Collagen hydrogels with concentrations of 3 mg/mL (Col3) and 10 mg/mL (Col10) were prepared, and their stiffness and microstructure were assessed using a rheometer and scanning electron microscopy, respectively. DPSCs were then encapsulated in the hydrogels, and their viability and differentiation capacity toward endothelial and odontogenic lineages were evaluated using live/dead assay and quantitative real-time polymerase chain reaction. For in vivo experiments, DPSC-encapsulated collagen hydrogels with different stiffness, with or without growth factors, were injected into pulp chambers of dentin tooth slices and implanted subcutaneously in severe combined immunodeficient (SCID) mice. Specifically, vascular endothelial growth factor (VEGF [50 ng/mL]) was loaded into Col3 and bone morphogenetic protein (BMP2 [50 ng/mL]) into Col10. Pulp–dentin regeneration was evaluated by histological and immunofluorescence staining. Data were analyzed using 1-way or 2-way analysis of variance accordingly (α = 0.05). Rheology and microscopy data revealed that Col10 had a stiffness of 8,142 Pa with a more condensed and less porous structure, whereas Col3 had a stiffness of 735 Pa with a loose microstructure. Furthermore, both Col3 and Col10 supported DPSCs' survival. Quantitative polymerase chain reaction showed Col3 promoted significantly higher von Willebrand factor (VWF) and CD31 expression after 7 and 14 d under endothelial differentiation conditions (P < 0.05), whereas Col10 enhanced the expression of dentin sialophosphoprotein (DSPP), alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), and collagen 1 (Col1) after 7, 14, and 21 d of odontogenic differentiation (P < 0.05). Hematoxylin and eosin and immunofluorescence (CD31 and vWF) staining revealed Col10+Col3+DPSCs+GFs enhanced pulp–dentin tissue regeneration. In conclusion, the collagen-based concentric construct modified by growth factors guided the specific lineage differentiation of DPSCs and promoted pulp–dentin tissue regeneration in vivo. [ABSTRACT FROM AUTHOR]

Purpose: Compared and analyzed the MRI imaging features of brain invasion otherwise benign (BIOB) meningiomas and WHO grade 1, grade 2 meningiomas, discussed the WHO grading of BIOB from the perspective of imaging. Materials and Methods: A retrospective analysis was performed on 675 meningiomas patients who carried on MRI examination from January 2006 to February 2022. Setting the 2022 Central nervous system (CNS) WHO Guidelines as the gold standard for pathological diagnosis. Statistical analysis of age, gender, and MRI features of meningiomas in relation to WHO grade and brain invasion. Results: Among 675 cases meningiomas, 543 (80.4%) were WHO grade 1, 123 (18.2%) were WHO grade 2, and 9 (1.3%) were WHO grade 3. There were 108 cases meningiomas with brain invasion (BI) (16.0%) and 567 cases without BI (84.0%). Among BI cases, 67 cases were BIOB. Compared the MRI features between BIOB and WHO grade 1 meningiomas, multivariate analysis demonstrated that the most strongly factors associated with distinguish them were enhancement degree, peritumoral edema, tumor–brain interface, fingerlike protrusion, mushroom sign, and bone invasion (AUC: 0.925 (0.901∼0.945), sensitivity: 0.925, specificity: 0.801). Compared the MRI features between BIOB and WHO grade 2 meningiomas, multivariate analysis demonstrated that the most strongly factors associated with distinguish them were enhancement degree and the tumor–brain interface (AUC: 0.779 (0.686∼0.841), sensitivity: 0.746, specificity: 0.732), their efficacy was slightly weaker. Conclusions: BIOB is more similar to WHO grade 2 meningiomas in clinical and imaging features than WHO grade 1, so we think that it may be reasonable to classify BIOB as WHO Grade 2 meningiomas in the guidelines. [ABSTRACT FROM AUTHOR]

Methacryloyloxydecyl dihydrogen phosphate (MDP) has been speculated to induce mineralization, but there has been no convincing evidence of its ability to induce intrafibrillar mineralization. Polymers play a critical role in biomimetic mineralization as stabilizers/inducers of amorphous precursors. Hence, MDP-induced biomimetic mineralization without polymer additives has not been fully verified or elucidated. By combining 3-dimensional stochastic optical reconstruction microscopy, surface zeta potentials, contact angle measurements, inductively coupled plasma–optical emission spectroscopy, transmission electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy with circular dichroism, we show that amphiphilic MDP can not only demineralize dentin by releasing protons as an acidic functional monomer but also infiltrate collagen fibrils (including dentin collagen), unwind the triple helical structure by breaking hydrogen bonds, and finally immobilize within collagen. MDP-bound collagen functions as a huge collagenous phosphoprotein (HCPP), in contrast to chemical phosphorylation modifications. HCPP can induce biomimetic mineralization itself without polymer additives by alternatively attracting calcium and phosphate through electrostatic attraction. Therefore, we herein propose the dual functions of amphiphilic MDP monomer with de- and remineralizing ability. MDP in the free state can demineralize dentin substrates by releasing protons, whereas MDP in the collagen-bound state as HCPP can induce intrafibrillar mineralization. The dual functions of MDP monomer with de- and remineralization properties might create a new epoch in adhesive dentistry and preventive dentistry. [ABSTRACT FROM AUTHOR]

Background: Diabetes nephropathy (DN) is a serious diabetic problem that may progress to renal failure. The root of Curcuma longa L., often known as turmeric, provides various health benefits. Bisacurone is a bioactive terpenoid found in small amounts in turmeric that possesses anti-inflammatory and antioxidant properties. The present study focuses on the potential protective effects of bisacurone against DN via reducing renal inflammation, oxidative stress, and apoptosis. Methods: Type 2 diabetes was created in rats by feeding them a high-fat/high-sugar diet for 8 weeks, followed by a low dose of streptozotocin and Bisacurone (50 and 100 μg/kg bisacurone) given for 4 weeks. Results: In diabetic rats, bisacurone reduced hyperglycemia, protected against body weight (BW) loss, lowered renal markers, reduced lipid profile alterations and avoided histological abnormalities. Bisacurone treatment reduced oxidative stress by decreasing malondialdehyde (MDA) levels while enhancing antioxidant defenses through superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) levels. Furthermore, bisacurone treatment activated the renal Nrf2/Keap1 signaling pathway but attenuated the high levels of NFκB p65, TNF-α, IL-1β, IL-6, Cox2, and iNOS. Bisacurone also reduced Bax, caspase-3, caspase-9 and cytochrome c but increased Bcl-2 in the kidneys of diabetic rats. Conclusion: In the present study, bisacurone reduces DN by reducing hyperglycemia, oxidative stress, inflammation, and apoptosis, while also increasing Nrf2/HO-1 signaling. [ABSTRACT FROM AUTHOR]

Background: Paraquat (PQ) poisoning induces severe acute kidney injury and causes extremely high rate of death. In this study, we aimed to investigate the protective effects of silymarin on PQ-induced acute kidney injury and explore the underlying mechanisms. Methods: A rat model was established through intraperitoneal injection of PQ. Rats were administrated with saline or silymarin for 3 days. Then, survival rate, physiological parameters, and renal injury score were evaluated. The apoptosis and oxidative stress in kidney tissues were determined through hematoxylin and eosin staining, quantitative reverse transcription polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assays. Results: Silymarin administration could significantly increase the survival rate of PQ-poisoned rats. It was found that silymarin treatment improved renal function, decreased injury score in kidney tissues, and inhibited the apoptosis and oxidative stress in PQ-induced acute kidney injury through the activating the signaling pathway of Nrf2 and promoting its nuclear translocation. Conclusion: Silymarin exhibited a protective effect against PQ-induced kidney injury, suggesting that treatment with this flavonoid could be a potential therapeutic agent for the treatment of acute kidney injury. [ABSTRACT FROM AUTHOR]

Accumulating evidence has revealed that long noncoding RNAs (lncRNAs) play essential roles in regulating cellular process of various cancers. There have been many studies on the biological functions of lncRNAs in colorectal cancer (CRC). In this research, we explored the role and mechanism of lncRNA ovarian tumor domain containing 6B antisense RNA1 (OTUD6B-AS1) in CRC. Here, we detected OTUD6B-AS1 expression in CRC tissues and cells by RT-qPCR. Functional experiments were performed to test alterations in different cellular processes. Moreover, to verify the binding ability among the indicated RNA molecules, we carried out RIP, RNA pull-down and luciferase reporter assays. According to our data, OTUD6B-AS1 expression was low in CRC tissues and cells. Functionally, overexpression of OTUD6B-AS1 inhibited cell proliferation, migration, invasion and EMT, and promoted cell apoptosis. Bioinformatic analysis and mechanistical experiments confirmed that OTUD6B-AS1 could act as a competitive endogenous RNA (ceRNA) to upregulate Proline-Rich Nuclear Receptor Coactivator 2 (PNRC2) expression by sequestering miR-21-5p. Further rescue experiments validated the inhibitory function of the OTUD6B-AS1/miR-21-5p/PNRC2 axis in cellular process of CRC. Overall, OTUD6B-AS1 inhibits cellular development in CRC by sponging miR-21-5p and upregulating PNRC2, providing a novel insight into the exploration on CRC treatment. [ABSTRACT FROM AUTHOR]

Patients with advanced salivary gland mucoepidermoid carcinoma (MEC) are treated with surgery and radiotherapy, as current systemic therapies are largely ineffective. As such, current treatment frequently leads to poor long-term survival due to locoregional recurrence or metastases. We have shown that salivary gland cancer stem cells (CSCs) are resistant to platinum-based chemotherapy and drive tumor progression. The purpose of this study was to investigate the effect of therapeutic inhibition of mTOR (mechanistic target of rapamycin) on resistance of CSCs to cisplatin, a prototypic platinum-based chemotherapeutic agent. Viability assays determined the effect of several inhibitors of PI3k/mTOR signaling (e.g., temsirolimus, BKM120, AZD8055, PF4708671) and/or cisplatin on survival of human MEC cells. The impact of mTOR inhibitors and/or cisplatin on MEC stemness was examined with salisphere assays, flow cytometry for ALDH/CD44 (CSC markers for MEC), and Western blots for Bmi-1 expression (marker of stem cell self-renewal). Salivary gland MEC patient-derived xenografts were used to examine the effect of cisplatin and/or temsirolimus on CSCs in vivo. We observed that cisplatin induced mTOR and S6K1 phosphorylation, increased the number and size of MEC salispheres, and induced Bmi-1 expression and the fraction of CSCs in MEC models in vitro. Cisplatin also increased the fraction of CSCs in vivo. In contrast, mTOR inhibition (e.g., temsirolimus) blocked cisplatin-induced Bmi-1 expression and salisphere formation in vitro. Remarkably, temsirolimus slowed down tumor growth and decreased the fraction of CSCs (P < 0.05) even in presence of cisplatin in a short-term in vivo experiment. Collectively, these results demonstrate that therapeutic inhibition of mTOR ablates cytotoxic-resistant CSCs, and they suggest that a combination of an mTOR inhibitor and platinum-based chemotherapy might be beneficial to patients with salivary gland mucoepidermoid carcinoma. [ABSTRACT FROM AUTHOR]

Fluoride facilitates the remineralization of dental hard tissues and affects bacterial activities. Therefore, it is extensively used as an anti-caries agent in clinical practice and daily life. Although some studies focused on understanding Streptococcus mutans' response to fluoride, the mechanism regulating intrinsic fluoride tolerance is not yet clear. Since the TetR family of transcription factors is associated with multidrug resistance, our aim was to evaluate whether they are related to fluoride tolerance in S. mutans. A mutant library including each S. mutans TetR gene was constructed and the transcription factor fluoride related transcriptional regulator (FrtR) was identified. The in-frame deletion of the S. mutans frtR gene resulted in decreased cell viability under fluoride in both the planktonic state and single-/dual-species biofilms. This in-frame frtR mutant was used for RNA-sequencing and the fluoride related permease gene (frtP) was found as 1 of the downstream genes directly regulated by FrtR. The recombinant FrtR protein was purified, and conserved DNA binding motifs were determined using electrophoretic mobility shift and DNase I footprinting assays. Finally, a series of mutant and complement strains were constructed to perform the minimum inhibitory concentration (MIC) assays, which indicated that frtP upregulation led to the increase of fluoride sensitivity. Collectively, our results indicate that FrtR is an important transcription factor regulating the frtP expression in S. mutans, thus affecting the intrinsic fluoride tolerance. Therefore, this study provides novel insights into a potential target to increase the S. mutans sensitivity to fluoride for a better prevention of dental caries. [ABSTRACT FROM AUTHOR]

Objective: Methamphetamine (MA) abuse induces neurotoxicity and causes neuronal cell apoptosis. Gastrodin is a traditional Chinese herbal medicine used for the treatment of nerve injuries, spinal cord injuries, and some central nervous system diseases as well. The present study investigated the neuroprotective effects of gastrodin against MA-induced neurotoxicity in neuronal cells and its potential protective mechanism. Methods: The primary cortex neuronal culture was divided into four groups (control group, MA group, MA + gastrodin group, and MA + gastrodin + small interfering RNA group). The neurotoxicity of MA was assessed by detecting apoptotic cells by terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling assay and cell viability by cell counting kit 8 (CCK-8) method, the Tuj1-positive cells and the average axonal length were detected by immunofluorescence, and the expressions of cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), cAMP-response element-binding (CREB), and brain-derived neurotrophic factor (BDNF) proteins were detected by Western blot. Results: The results of CCK-8 assay showed that 0.5 mM MA was an optimal concentration that induced neurotoxicity (p < 0.01). Pretreatment with 25 mg/L gastrodin exerted maximum protective effects on neuronal cells. The expression levels of cAMP, PKA, phosphorylated PKA, CREB, phosphorylated CREB, and BDNF proteins were decreased in the MA group, and pretreatment with gastrodin upregulated the expression levels of these proteins (p < 0.01). The expressions of PKA and CREB proteins showed no significant changes in the control group, MA group, and gastrodin group. Compared the MA + gastrodin + small interfering RNA group with MA + gastrodin group, the Tuj1-positive cells and the average axonal length were decreased significantly, while the number of apoptotic cells was increased (p < 0.05). Conclusion: Gastrodin has neuroprotective effects against MA-induced neurotoxicity, which exerts neuroprotective effects via regulation of cAMP/PKA/CREB signaling pathway and upregulates the expression of BDNF. [ABSTRACT FROM AUTHOR]

Interactions with the microenvironment modulate the fate of stem cells in perivascular niches in tissues (e.g., bone) and organs (e.g., liver). However, the functional relevance of the molecular crosstalk between endothelial cells and stem cells within the perivascular niche in dental pulps is unclear. Here, we tested the hypothesis that endothelial cell-initiated signaling is necessary to maintain self-renewal of dental pulp stem cells. Confocal microscopy showed that ALDH1high and Bmi-1high stem cells are preferentially localized in close proximity to blood vessels in physiological human dental pulps. Secondary orosphere assays revealed that endothelial cell-derived factors (e.g., interleukin-6 [IL-6]) promote self-renewal of dental pulp stem cells cultured in low-attachment conditions. Mechanistic studies demonstrated that endothelial cell-derived IL-6 activates IL-6R (IL-6 Receptor) and signal transducer and activator of transcription 3 (STAT3) signaling and induces expression of Bmi-1 (master regulator of stem cell self-renewal) in dental pulp stem cells. Transplantation of dental pulp stem cells stably transduced with small hairpin RNA (shRNA)-STAT3 into immunodeficient mice revealed a decrease in the number of blood vessels surrounded by ALDH1high or Bmi-1high cells (perivascular niches) compared to tissues formed upon transplantation of vector control stem cells. And finally, in vitro capillary sprouting assays revealed that inhibition of IL-6 or STAT3 signaling decreases the vasculogenic potential of dental pulp stem cells. Collectively, these data demonstrate that endothelial cell-derived IL-6 enhances the self-renewal of dental pulp stem cells via STAT3 signaling and induction of Bmi-1. These data suggest that a crosstalk between endothelial cells and stem cells within the perivascular niche is required for the maintenance of stem cell pools in dental pulps. [ABSTRACT FROM AUTHOR]

It is known that dental pulp stem cells (DPSCs) can be induced to differentiate into vasculogenic endothelial (VE) cells. However, the process that results in sprouting and anastomosis of DPSC-derived vessels remains unclear. Here, we performed studies to understand the mechanisms underpinning the anastomosis of the host vasculature with blood vessels generated by DPSCs (a model for mesenchymal stem cells). VE-cadherin-silenced primary human DPSCs seeded in tooth slice/scaffolds and transplanted into the subcutaneous space of immunodeficient mice generated fewer functional blood vessels (i.e., anastomosed with the host vasculature) than control DPSCs transduced with scrambled sequences. Both VE-cadherin-silenced and mitogen-activated protein kinase kinase 1 (MEK1)-silenced cells showed a decrease in the number of capillary sprouts in vitro. Interestingly, DPSC stably transduced with a VE-cadherin reporter demonstrated that vascular endothelial growth factor (VEGF) induces VE-cadherin expression in sprouting DPSCs undergoing anastomosis, but not in quiescent DPSCs. To begin to understand the mechanisms regulating VE-cadherin, we stably silenced MEK1 and observed that VEGF was no longer able to induce VE-cadherin expression and capillary sprout formation. Notably ERG, a transcriptional factor downstream from MEK/ERK, binds to the promoter region of VE-cadherin (chip assay) and is induced by VEGF in DPSCs. Collectively, these data defined a signaling pathway triggered by VEGF that results in phosphorylation of MEK1/ERK and activation of ERG leading to expression of VE-cadherin, which is required for anastomosis of DPSC-derived blood vessels. In conclusion, these results unveiled a signaling pathway that enables the generation of functional blood vessels upon vasculogenic differentiation of DPSCs. [ABSTRACT FROM AUTHOR]

Recent years have seen substantial shifts in cultural attitudes towards cannabis for medical and recreational use. However, legalizing recreational marijuana may have adverse effects on individual and public health. As the most widely used illicit agent, cannabis is commonly reported to disrupt learning and memory. Unfortunately, the molecular mechanisms underlying behavioral impairment by cannabis abuse remain poorly understood. Tetrahydrocannabinol (THC), a major component in cannabis, causes short-term effects on the visual system, but little is known about persisting visual disturbances. This study was to investigate the effects of systemic administration with THC on retina and explore its underlying mechanisms. BALB/c mice were treated with 1 or 2 mg/kg THC intraperitoneally daily for 2 months, mice treated with vehicle as negative control. The retinal function was tested by electroretinography after THC treatment. Morphology and pathology changes of retina were detected by hematoxylin and eosin staining. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay was used to detect the apoptosis in photoreceptor cells. Enzyme-linked immunosorbent assay was used to show the inflammatory responses and oxidative stress. mRNA and protein changes were measured by real-time polymerase chain reaction and Western blot to explore the underlying mechanisms. Results indicated that 2-month treatment with THC caused retinal damage, evidenced by its functional loss and increased apoptosis in photoreceptor cells through inducing inflammatory responses and oxidative stress. Our study demonstrated that systemic administration with THC caused toxic effects on retinas of BALB/c mice, suggesting the potential mechanisms for the retina damage caused by cannabis abuse. [ABSTRACT FROM AUTHOR]

Sonic hedgehog (Shh) in dental epithelium regulates tooth morphogenesis by epithelial-mesenchymal signaling transduction. However, the action of Shh signaling regulation in this process is not well understood. Here we find that mesenchymal Suppressor of Fused (Sufu), a major negative regulator of Shh signaling, plays an important role in modulating the tooth germ morphogenesis during the bud-to-cap stage transition. Deletion of Sufu in dental mesenchyme by Dermo1-Cre mice leads to delayed development of mandibular molar into cap stage with defect of primary enamel knot (EK) formation. We show the disruption of cell proliferation and programmed cell death in dental epithelium and mesenchyme in Sufu mutants. Epithelial-specific adhesion molecule E-cadherin is evidently reduced in the bilateral basal cells of tooth germ at E14.5. The cells in the presumptive EK, predominantly expressing P-cadherin, appear stratified but fail to condense. Moreover, the transcripts of primary EK marker genes, including Shh, Fgf4, and p21, are significantly decreased compared to controls. In contrast, we find that deficiency of Sufu results in elevation of Shh signaling in mesenchyme, indicated by the significant upregulation of Gli1 and Ptch1. Meanwhile, the expression of Bmp4 and Fgf3, the critical factors of mesenchymal-epithelial induction, is significantly inhibited in dental mesenchyme. Furthermore, the expression of Runx2 experiences a transient decrease at the bud stage. Taken together, these data suggest that mesenchymal Sufu is necessary for tuning the Shh signaling, which may act as an upstream modulator of Bmp4 and Fgf3 to coordinate the interplay between the dental mesenchyme and epithelium of tooth germ. [ABSTRACT FROM AUTHOR]

The Wnt ligands display varied spatiotemporal expression in the epithelium and mesenchyme in the developing tooth. Thus far, the actions of these differentially expressed Wnt ligands on tooth development are not clear. Shh expression specifies the odontogenic epithelium during initiation and is consistently restricted to the dental epithelium during tooth development. In this study, we inactivate Wntless ( Wls), the key regulator for Wnt trafficking, by Shh-Cre to investigate how the Wnt ligands produced in the dental epithelium lineage act on tooth development. We find that conditional knockout of Wls by Shh-Cre leads to defective ameloblast and odontoblast differentiation. WlsShh-Cre teeth display reduced canonical Wnt signaling activity in the inner enamel epithelium and the underlying mesenchyme at the early bell stage, as exhibited by target gene expression and BAT-gal staining. The expression of Wnt5a and Wnt10b is not changed in WlsShh-Cre teeth. By contrast, Wnt10a expression is significantly increased in response to epithelial Wls deficiency. In addition, the expression of Hedgehog signaling pathway components Shh, Gli1, and Patched1 was greatly decreased in WlsShh-Cre teeth. Epithelial Wls loss of function in Shh lineage also leads to aberrant cell proliferation in dental epithelium and mesenchyme at embryonic day 16.5; however, the cell apoptosis is unaffected. Moreover, we find that Decorin and Col1a1, the key markers for odontoblast differentiation that are downregulated in WlsShh-Cre teeth, act as direct downstream targets of the canonical Wnt signaling pathway by chromatin immunoprecipitation analysis. Additionally, Decorin and Col1a1 expression can be increased by lithium chloride (LiCl) treatment in the in vitro tooth explants. Taken together, our results suggest that the spatial expression of Wnt ligands within the dental epithelial lineage regulates the differentiation of tooth structures in later stages. [ABSTRACT FROM AUTHOR]

Flax fibre-reinforced unsaturated polyester composite laminates were fabricated by vacuum bagging process and their impact and post-impact responses were investigated through experimental testing and finite element simulations. Samples of 60 mm × 60 mm × 6.2 mm were cut from the composite laminates and were subjected to a low-velocity impact loading to near perforation using hemispherical steel impactor at three different energy levels, 25, 27 and 29 Joules. Post-impact was employed to obtain full penetration. The impacted composite plates were modelled with various lay-ups using finite element software LS-DYNA (LS-DYNA User's Manual 1997) to provide a validated finite element model for the future investigation in the field. The effects of impact and post-impact on the failure mechanisms were evaluated using scanning electron microscopy. Parameters measured were load bearing capability, energy absorption and damage modes. The results indicate that both peak load and the energy absorption were reduced significantly after the post-impact events. Consequently, it was observed from the visual images of the damages sites that the extent of damage increased with increased incident energy and post-impact events. [ABSTRACT FROM AUTHOR]

Previously, we reported that the fluorapatite (FA)-modified polycaprolactone (PCL) nanofiber could be an odontogenic/osteogenic inductive tissue-engineering scaffold by inducing stem cell differentiation and mineralization. The present study aimed to explore which of the signal pathways affected this differentiation and mineralization process. The Human Signal Transduction PathwayFinder RT2 Profiler PCR Array was used to analyze the involvement of potential signal transduction pathways during human dental pulp stem cell (DPSCs) osteogenic differentiation induced by FA-modified PCL nanofiber scaffolds. Based on the results, perturbation studies of the signaling pathways hedgehog, insulin, and Wnt were performed. Moreover, the autophagy process was studied, as indicated by the expression of the microtubule-associated protein 1 light chain 3A/B-II (LC3-II) and the cell osteogenic phenotypic changes. In a comparison of the cells grown on PCL + FA scaffolds and those on PCL-only scaffolds, the transcript expression of BMP2, BMP4, FOXA2, PTCH1, WNT1, and WNT2 (PCR array-labeled signal proteins of the hedgehog pathway); CEBPB, FASN, and HK2 (PCR array-labeled signal proteins of the insulin pathway); and CCND1, JUN, MYC, TCF7, and WISP1 (PCR array-labeled signal proteins of the Wnt pathway) doubled at day 14 when obvious cell osteogenic differentiation occurred. Phenotypically, in all the perturbation groups at day 14, ALP activity, OPN, and autophagy marker LC3-II expression were coincidently decreased. Consistently, no positive alizarin red staining or von Kossa staining was observed in the specimens from these perturbation groups at day 28. The results showed that when obvious cell differentiation occurred at day 14 on PCL + FA control groups, the inhibition of the hedgehog, insulin, and Wnt pathways significantly decreased DPSC osteogenic differentiation and mineralization. The osteogenic differentiation of DPSCs grown on FA-modified PCL scaffolds appeared to be positively modulated by the hedgehog, insulin, and Wnt signal pathways, which were coordinated with and/or mediated by the cell autophagy process. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the mortality and causes of death in Chinese patients with systemic lupus erythematosus. Methods: We collected the clinical data of all consecutive adult systemic lupus erythematosus patients at the Rheumatology department of Peking University First Hospital between January 2007 and December 2015. The primary causes of death were identified, the standardized mortality ratio and years of life lost were calculated, and the survival and variables associated with mortality were determined by Kaplan-Meier and Cox regression analysis respectively. Results: The mean age of all 911 patients (814 females and 97 males) was 37.8±14.7 years, the median disease duration at recruitment was 2.6 (0.5-7.0) years, and the median follow-up duration was 3.0 (1.4-5.1) years. Among the 911 patients who were successfully followed up, 45 patients died. Infection (31.1%) was the leading cause of death followed by renal failure, pulmonary arterial hypertension and cerebrovascular diseases. The overall age and sex-adjusted standardized mortality ratio was 3.2 (95% confidence interval 2.4-4.0), and the years of life lost for women and men were 29.8 and 9.4 respectively. Overall survival at 1, 5 and 10 years was 98.2%, 95.3% and 93.7% respectively. Older age at disease onset, infection, autoimmune hemolytic anemia, thrombocytopenia and pulmonary arterial hypertension were independent risk factors for the mortality of systemic lupus erythematosus patients, and longer disease duration at recruitment was an independent protective factor. Conclusions: Mortality of systemic lupus erythematosus patients in China was substantial, especially in females, with infection the leading cause of death. Older age at disease onset, infection, autoimmune hemolytic anemia, thrombocytopenia and pulmonary arterial hypertension were associated with poor outcomes. [ABSTRACT FROM AUTHOR]

Objective The objective of this study was to determine the efficacy of hydroxychloroquine (HCQ) in the primary thrombosis prevention of antiphospholipid antibody (aPL)-positive patients with no other systemic autoimmune diseases. Methods Under the auspices of Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking, a multicenter, international, randomized controlled trial (RCT) was initiated, in which persistently aPL-positive but thrombosis-free patients without systemic autoimmune diseases were randomized to receive HCQ or no treatment in addition to their standard regimen. The primary objective was the efficacy of HCQ in preventing the first thrombosis. The secondary objectives were the thrombosis incidence rate, and the effects of HCQ on aPL profile and mortality rate. Patients were risk-stratified based on antiplatelet agent use. The goal was to follow patients every 6 months for 5 years. Results We recruited 20 persistently aPL-positive patients (female: 19, mean age: 46.6 ± 9.9 years, and baseline antiplatelet medication: 14); 9/20 were randomized to HCQ. During the mean follow-up of 1.7 years, no patients developed thrombosis or a serious adverse event. The study was terminated early due to the low recruitment rate, exacerbated by the prolonged manufacturing shortage and significant price increase of HCQ in the United States. Conclusion Given that a small number of patients with a relatively short follow-up were enrolled in our RCT, and no patients developed thrombosis, we cannot accurately assess the effectiveness of HCQ for primary thrombosis prevention in persistently aPL-positive patients with no other systemic autoimmune diseases. Our experience suggests that conducting an international RCT, especially without pharmaceutical support, is an extremely challenging undertaking. [ABSTRACT FROM AUTHOR]

Stress corrosion cracking (SCC) behaviour of 316L stainless steel in CO2–H2S–Cl−environments with and without methyldiethanolamine (MDEA) was investigated by slow strain rate testing and scanning electron microscopy (SEM). The results show that elongation ratio, reduction in area ratio (RAR) and time to failure ratio (TTFR) of 316L stainless steel were low in CO2–H2S–Cl−environments. The corresponding fractography exhibited flat brittle fracture with quasi-cleavage pattern, indicative of high SCC susceptibility. Hydrogen penetration and corrosion pits could be responsible for the high SCC susceptibility of 316L stainless steel in this condition. For the CO2–H2S–Cl−environments in the presence of MDEA, 316L stainless steel possessed high ER, RAR and TTFR (nearly 100%). High SCC resistance of 316L stainless steel could be associated with MDEA induced removal of H2S/CO2and absorption on the steel surface. [ABSTRACT FROM AUTHOR]

Previous studies have shown that ropivacaine is the least neurotoxic local anaesthetic. Most of the data derive from short-term ropivacaine injection into the subarachnoid space. Intrathecal administration for a prolonged period, and the histological changes and behavioural effects of repeated intrathecal administration, have not previously been investigated. We studied the possible neurotoxicity of intrathecal injection of ropivacaine in a rat model. Rats received 0.12 ml/kg body weight of ropivacaine at concentrations of 0.5 or 1%, or normal saline only, via an implanted intrathecal catheter at 90-minute intervals for 12 hours. On days 1, 3, 5, 7, 14 and 28, the spinal cord was examined by light and electron microscopy at the L3 level. We assessed sensory thresholds to noxious stimulation, behavioural change and protein kinase B immunoreactivity for possible neuronal injury within the spinal cord. Ropivacaine 1% induced thermal hyperalgesia and mechanical allodynia, neuronal injury characterised by tissue oedema, proliferation of glial cells, neuronal morphology changes and degeneration and protein kinase B expression. There were no significant differences in motor function as a result of different concentrations of ropivacaine. Repeated intrathecal injection of ropivacaine 1% can induce neurotoxicity in rats. Our data suggests that expression of protein kinase B might be involved in this neurotoxicity. [ABSTRACT FROM AUTHOR]

C-reactive protein is a marker of inflammatory response and has been widely investigated in cardiovascular and infectious diseases, especially to monitor therapeutic success. However, its role as a predictor of clinical outcome in critically ill patients remains uncertain and controversial. The objective of this study was to investigate the predictive value of C-reactive protein in critically ill patients. The databases of PubMed, the Cochrane clinical trial database and EMBASE (from inception to August 2010) were searched. Prospective non-randomised clinical studies comparing C-reactive protein concentrations between survivors and non-survivors were included. Pooled mean difference in C-reactive protein concentrations between survivors and non-survivors was calculated. Heterogeneity was analysed by I2. Sensitivity and subgroup analyses were conducted to explore the heterogeneity. Fourteen studies containing a total of 1969 patients were finally included in our analysis. The weighted mean difference in the C-reactive protein levels between survivors and non-survivors was 9.15 mg/l (95% confidence interval -6.50 to 24.81). The heterogeneity was large with I2 = 92%. Subsequent investigation of the heterogeneity with sensitivity analyses yielded no significant differences. The subgroup analysis showed that the weighted mean difference in early (within 48 hours) C-reactive protein levels between survivors and non-survivors was not significantly different, in contrast to the late (beyond 48 hours) C-reactive protein level. This was significantly greater in non-survivors with a weighted mean difference of 63.80 mg/l (95% confidence interval 35.67 to 91.93). Our systematic review shows that while the early C-reactive protein concentration is not a good predictor of survival in critically ill patients, the late C-reactive protein concentration may help to identify patients who are at risk of death. [ABSTRACT FROM AUTHOR]

Optimization of the vibration transmission of an internal floating-raft system and the resultant sound radiation of the fluid-loaded cylindrical structure is presented. The influences of different objective functions, fluid loading, external loading, and an optimized frequency band on the optimization results are investigated in detail. The frequency-response-function (FRF)-based substructuring method and the coupled finite element method–boundary element method are employed to study the vibration transmission from vibrating machines to the base and the vibro-acoustic behaviour of the fluid-loaded cylindrical structure respectively. An FRF-based substructuring sensitivity analysis is applied to obtain the optimal values of the stiffness of isolators under five objective functions in the low-frequency range. The optimized results demonstrate that some of the objective functions are equivalent to each other and can be replaced by each other. The reasons for the difference in the variation trends of the stiffness of the lower isolators for different objective functions are discussed in detail. The fluid loading does have an impact on the optimal results and it influences the variation trend of only the stiffness of the isolators that support the machines without an externally applied load. The external loading and the optimized frequency band are two factors to be carefully considered in the design stage. This investigation reveals that it should take into account fluid–structure interaction and comprehensively consider different vibration or acoustic objectives in the design stage. [ABSTRACT FROM PUBLISHER]

The purpose of this study was to investigate if low doses of levobupivacaine (0.1%) produce complete sensory blockade in preoperative axillary brachial plexus block and to compare the effect of different doses of levobupivacaine on sensory and motor blockade. A total of 110 patients scheduled for elective forearm or hand surgery were randomly allocated to receive 36 ml or 72 ml of levobupivacaine 0.1% or 36 ml of levobupivacaine 0.25%. In each group, volumes were equally distributed in the four nerve territories. In all patients, the sensory and motor block was assessed at five, 10, 20 and 30 minutes after the placement of axillary block. Complete sensory block was obtained in 94.4% of patients receiving 36 ml of levobupivacaine 0.1%, 92.1% of those receiving 72 ml of levobupivacaine 0.1%, and 97.1% of those receiving 36 ml of levobupivacaine 0.25%. There was no significant difference either in the onset of the sensory and motor block or duration of the sensory and motor block. This study demonstrates that 36 ml of levobupivacaine 0.1% (36 mg) is as effective as higher doses and volumes in axillary brachial plexus blockade. [ABSTRACT FROM AUTHOR]

As a major intracellular degradation and recycling machinery, autophagy plays an important role in maintaining cellular homeostasis and remodeling during normal development. Our previous study showed that fluorapatite (FA) crystal-coated electrospun polycaprolactone (PCL) was capable of inducing differentiation and mineralization of human dental pulp stem cells. However, how autophagy changes and whether autophagy plays a vital role during these processes is still unknown. In this study, we seeded STEMPRO human adipose-derived stem cells (ASCs) on both PCL+FA and PCL scaffolds to investigate the osteogenic inductive ability of FA crystals and we observed the autophagy changes of these cells. Scanning electron microscopy and fluorescence microscopy images, along with DNA quantitation, showed that both PCL+FA and PCL scaffolds could sustain ASC growth but only the PCL+FA scaffold could sustain cell mineralization. This was confirmed by alkaline phosphatase activity and Alizarin red and Von Kossa staining results. The autophagy RT2 Profiler polymerase chain reaction array analysis showed many autophagy-related genes changes during ASC differentiation. Western blot analysis indicated that several autophagy-related proteins fluctuated during the procedure. Among them, the microtubule-associated protein 1 light chain 3 (LC3)-II protein changes of the ASCs grown on the 2- or 3-dimensional environments at 6 h, 12 h, 1 d, 3 d, 7 d, 14 d, and 21 d reached a peak value at day 7 during osteogenesis. At earlier stages (from day 0 to day 3), the addition of autophagy inhibitors (3-mathyladenine, bafilomycin A1, and NH4Cl) attenuated the expression of osteogenic related markers (osteopontin, alkaline phosphatase activity, Alizarin red, and Von Kossa) compared with the control group. All data indicated that autophagy played an important role in ASC differentiation on the PCL+FA scaffold. Inhibition of autophagy before day 3 strongly inhibited osteogenic differentiation and mineralization of ASCs in the 3-dimensional model. This observation further elucidates the mechanism of autophagy in mesenchymal stem cell osteogenic differentiation. [ABSTRACT FROM AUTHOR]

Self-assembled nanolayering structures have been reported in resin-dentin interfaces created by adhesives that contain 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP). These structures have been hypothesized to contribute to bond durability. The objective of the present study was to determine the extent of nanolayering in resin-dentin interfaces after application of commercialized 10-MDP-containing self-etch and universal adhesives to human dentin. Seven commercialized adhesives were examined: Adhese Universal (Ivoclar-Vivadent), All-Bond Universal (Bisco, Inc.), Clearfil SE Bond 2, Clearfil S3 Bond Plus, Clearfil Universal Bond (all from Kuraray Noritake Dental Inc.), G-Premio Bond (GC Corp.), and Scotchbond Universal (3M ESPE). Each adhesive was applied in the self-etch mode on midcoronal dentin according to the respective manufacturer's instructions. Bonded specimens (n = 6) were covered with flowable resin composite, processed for transmission electron microscopy, and examined at 30 random sites without staining. Thin-film glancing angle X-ray diffraction (XRD) was used to detect the characteristic peaks exhibited by nanolayering (n = 4). The control consisted of 15%wt, 10%wt, and 5%wt 10-MDP (DM Healthcare Products, Inc.) dissolved in a mixed solvent (ethanol and water weight ratio 9:8, with photoinitiators). Experimental primers were applied to dentin for 20 s, covered with hydrophobic resin layer, and examined in the same manner. Profuse nanolayering with highly ordered periodicity (~3.7 nm wide) was observed adjacent to partially dissolved apatite crystallites in dentin treated with the 15% 10-MDP primer. Three peaks in the 2θ range of 2.40° (3.68 nm), 4.78° (1.85 nm), and 7.18° (1.23 nm) were identified from thin-film XRD. Reduction in the extent of nanolayering was observed in the 10% and 5% 10-MDP experimental primer-dentin interface along with lower intensity XRD peaks. Nanolayering and characteristic XRD peaks were rarely observed in specimens prepared from the commercialized adhesives. The sparsity of nanolayering in resin-dentin interfaces created by commercialized adhesives challenges its clinical effectiveness as a mechanism for improving bond longevity in dentin bonding. [ABSTRACT FROM AUTHOR]

Cleft palate represents one of the major congenital birth defects in humans. Despite the essential roles of ectodermal canonical Wnt and mesenchymal Wnt signaling in the secondary palate development, the function of mesenchymal canonical Wnt activity in secondary palate development remains elusive. Here we show that Gpr177, a highly conserved transmembrane protein essential for Wnt trafficking, is required for secondary palate development. Gpr177 is expressed in both epithelium and mesenchyme of palatal shelves during mouse development. Wnt1Cre-mediated deletion of Gpr177 in craniofacial neural crest cells leads to a complete cleft secondary palate, which is formed mainly due to aberrant cell proliferation and increased cell death in palatal shelves. By BATGAL staining, we reveal an intense canonical Wnt activity in the anterior palate mesenchyme of E12.5 wild-type embryos but not in Gpr177Wnt1-Cre embryos, suggesting that mesenchymal canonical Wnt signaling activated by Gpr177-mediated mesenchymal Wnts is critical for secondary palate development. Moreover, phosphorylation of JNK and c-Jun is impaired in the Gpr177Wnt1-Cre palate and is restored by implantation of Wnt5a-soaked beads in the in vitro palate explants, suggesting that Gpr177 probably regulates palate development via the Wnt5a-mediated noncanonical Wnt pathway in which c-Jun and JNK are involved. Importantly, certain cellular processes and the altered gene expression in palates lacking Gpr177 are distinct from that of the Wnt5a mutant, further demonstrating involvement of other mesenchymal Wnts in the process of palate development. Together, these results suggest that mesenchymal Gpr177 is required for secondary palate development by regulating and integrating mesenchymal canonical and noncanonical Wnt signals. [ABSTRACT FROM AUTHOR]