Slc26a3 deficiency is associated with loss of colonic HCO3 (-) secretion, absence of a firm mucus layer and barrier impairment in mice

AIM

Downregulated in adenoma (DRA, Slc26a3) is a member of the solute carrier family 26 (SLC26), family of anion transporters, which is mutated in familial chloride-losing diarrhoea (CLD). Besides Cl(-) -rich diarrhoea, CLD patients also have a higher-than-average incidence of intestinal inflammation. In a search for potential explanations for this clinical finding, we investigated colonic electrolyte transport, the mucus layer and susceptibility against dextran sodium sulphate (DSS)-induced colitis in Slc26a3(-/-) mice.

METHODS

HCO3 (-) secretory (JHCO3 (-) ) and fluid absorptive rates were measured by single-pass perfusion in vivo and in isolated mid-distal colonic mucosa in Ussing chambers in vitro. Colonocyte intracellular pH (pHi ) was assessed fluorometrically, the mucus layer by immunohistochemistry and colitis susceptibility by the addition of DSS to the drinking water.

RESULTS

HCO3 (-) secretory (JHCO3- ) and fluid absorptive rates were strongly reduced in Slc26a3(-/-) mice compared to wild-type (WT) littermates. Despite an increase in sodium/hydrogen exchanger 3 (NHE3) mRNA and protein expression, and intact acid-activation of NHE3, the high colonocyte pH in Slc26a3(-/-) mice prevented Na(+) /H(+) exchange-mediated fluid absorption in vivo. Mucin 2 (MUC2) immunohistochemistry revealed the absence of a firm mucus layer, implying that alkaline secretion and/or an absorptive flux may be necessary for optimal mucus gel formation. Slc26a3(-/-) mice were highly susceptible to DSS damage.

CONCLUSIONS

Deletion of DRA results in severely reduced colonic HCO3 (-) secretory rate, a loss of colonic fluid absorption, a lack of a firmly adherent mucus layer and a severely reduced colonic mucosal resistance to DSS damage. These data provide potential pathophysiological explanations for the increased susceptibility of CLD patients to intestinal inflammation.

Subretinal transplantation of rat MSCs and erythropoietin gene modified rat MSCs for protecting and rescuing degenerative retina in rats

For degenerative retinal diseases, like the acquired form exemplified by age-related macular degeneration (AMD), there is currently no cure. This study was to explore a stem cell therapy and a stem cell based gene therapy for sodium iodate (SI)-induced retinal degeneration in rats. Three cell types, i.e., rat mesenchymal stem cells (rMSCs) alone, erythropoietin (EPO) gene modified rMSCs (EPO-rMSCs) or doxycycline (DOX) inducible EPO expression rMSCs (Tet-on EPO-rMSCs), were transplanted into the subretinal spaces of SI-treated rats. The rMSCs were prepared for transplantation after 3 to 5 passages or modified with EPO gene. During the 8 weeks after the transplantation, the rats treated with rMSCs alone or with two types of EPO-rMSCs were all monitored with fundus examination, fundus fluorescein angiography (FFA) and electroretinogram. The transplantation efficiency of donor cells was examined for their survival, integration and differentiation. Following the transplantation, labeled donor cells were observed in subretinal space and adopted RPE morphology. EPO concentration in vitreous and retina of SI-treated rats which were transplanted with EPO-rMSCs or Tet-on EPO-rMSCs was markedly increased, in parallel with the improvement of retinal morphology and function. These findings suggest that rMSCs transplantation could be a new therapy for degenerative retinal diseases since it can protect and rescue RPE and retinal neurons, while EPO gene modification to rMSCs could be an even better option.

Value of alpha-fetoprotein and clinical characteristics in patients with liver neoplasm

This article aimed to investigate the value of α-fetoprotein (AFP) for the diagnosis of hepatocellular carcinoma (HCC) and to evaluate the relationship between AFP and various clinical variables of HCC comprehensively. A retrospective study of postoperative patients diagnosed with liver neoplasm from two Chinese centers was enrolled in our study.A total of 3050 patients were included. The best cut-off point of AFP for the diagnosis of HCC was 20ng/ml with ideal sensitivity (69.74%), specificity (91.18%), LR (4.12) and YI (0.61). Non-HBV infection patients showed the highest specificity (94.44%) but lowest sensitivity (60.13%). In HBV infection. Patients, HBsAg, HBeAb, and HBcAb positive patients had the highest sensitivity (79.55%) and specificity (58.49%). AFP levels increased significantly in symptomatic patients (p=0.011). Those patients with tumor sizes ≥10cm had much higher serum AFP level compared with smaller tumors ones (p=0.014). AFP levels increased remarkably in patients with vascular invasion (p=0.015). Stepwise logistic regression showed tumor size (≥10cm) was an independent predictor of elevated AFP (OR=2.743, 95%CI: 1.167-6.447, P=0.021). The best discriminating AFP value for the diagnosis of HCC is 20ng/ml; HBsAg, HBeAb and HBcAb positive patients have the optimal sensitivity and specificity; tumor size ≥ 10cm is an independent predictor of elevated AFP.

Genetic variants for type 2 diabetes and new-onset cancer in Chinese with type 2 diabetes

BACKGROUND

Diabetes is associated with an increased risk of cancer. This study aimed to evaluate associations between recently reported type 2 diabetes (T2D) susceptibility genetic variants and cancer risk in a prospective cohort of Chinese patients with T2D.

METHODS

Seven single nucleotide polymorphisms (SNP) in IGF2BP2, CDKAL1, SLC30A8, CDKN2A/B, HHEX and TCF7L2, all identified from genome-wide association studies of T2D, were genotyped in 5900 T2D patients [age mean ± SD = 57 ± 13 years, % males = 46] without any known cancer at baseline. Associations between new-onset of cancer and SNPs were tested by Cox proportional hazard models with adjustment of conventional risk factors.

RESULTS

During the mean follow-up period of 8.5 ± 3.3 years, 429 patients (7.3%) developed cancer. Of the T2D-related SNPs, the G-alleles of HHEX rs7923837 (hazard ratio [HR] (95% C.I.) = 1.34 (1.08-1.65); P = 6.7 ×10(-3) under dominant model) and TCF7L2 rs290481 (HR (95% C.I.) = 1.16 (1.01-1.33); P = 0.040 under additive model) were positively associated with cancer risk, while the G-allele of CDKAL1 rs7756992 was inversely associated (HR (95% C.I.) = 0.80 (0.65-1.00); P = 0.048 under recessive model). The risk alleles of these significant SNPs exhibited combined effect on increasing cancer risk (per-allele HR (95% C.I.) = 1.25 (1.12-1.39); P = 4.8 × 10(-5)). The adjusted cancer risk was 2.41 (95% C.I. 1.23-4.69) for patients with four risk alleles comparing to patients without risk allele.

CONCLUSIONS

T2D-related variants HHEX rs7923837, TCF7L2 rs290481 and CDKAL1 rs7756992 increased cancer risk in patients with diabetes.

IMPACT

Our findings provide novel insights into the pathogenesis of cancer in diabetes.

Effects of common polymorphisms rs2910164 in miR-146a and rs11614913 in miR-196a2 on susceptibility to colorectal cancer: a systematic review meta-analysis

PURPOSE

Emerging evidence has shown that single nucleotide polymorphisms occurred in microRNAs may contribute to the development of colorectal cancer (CRC). rs2910164 in miR-146a and rs11614913 in miR-196a2 are suggested to be associated with the susceptibility to CRC, but individually published studies revealed inconclusive results. To systematically summarize the possible correlationship between these polymorphisms and CRC risk, we performed this meta-analysis.

METHODS

We retrieved the relevant articles of the associations between these two microRNA polymorphisms and susceptibility to CRC for the period up to July 1, 2013. A total of seven articles were identified with 2,143 cases and 2,457 controls for miR-146a rs2910164, 1,594 cases and 2,252 controls for miR-196a2 rs11614913. Odds ratio and 95 % confidence interval were calculated to investigate the strength of the association.

RESULTS

The pooled analysis showed that miR-146a rs2910164 did not reveal any correlation with CRC susceptibility. However, a decreased risk was observed between miR-196a2 rs11614913 and CRC in all genetic models.

CONCLUSION

Our current meta-analysis demonstrates that miR-196a2 rs11614913 most likely contributes to decreased risk of CRC, whereas miR-146a rs2910164 may not be associated with the susceptibility to CRC.

Optimization of in vitro cell labeling methods for human umbilical cord-derived mesenchymal stem cells

BACKGROUND AND OBJECTIVES

Human umbilical cord-derived mesenchymal stem cells (hUCMSCs) are a novel source of seed cells for cell therapy and tissue engineering. However, in vitro labeling methods for hUCMSCs need to be optimized for better detection of transplanted cells.

AIM OF THE STUDY

To identify the most stable and efficient method for labeling hUCMSCs in vitro.

MATERIALS AND METHODS

hUCMSCs were isolated using a modified enzymatic digestion procedure and cultured. hUCMSCs of passage three (P3) were then labeled with BrdU, PKH26, or lentivirus-GFP and passaged further. Cells from the first labeled passage (LP1), the fourth labeled passage (LP4) and later passages were observed using a fluorescence microscope. The differentiation potential of LP4 cells was assessed by induction with adipogenic and osteogenic medium. Flow cytometry was used to measure the percentage of labeled cells and the percentage of apoptotic or dead cells. The labeling efficiencies of the three hUCMSC-labeling methods were compared in vitro.

RESULTS

BrdU, PKH26, and lentivirus-GFP all labeled LP1 cells with high intensity and clarity. However, the BrdU labeling of the LP4 cells was vague and not localized to the cell nuclei; LP9 cells were not detected under a fluorescence microscope. There was also a significant decrease in the fluorescence intensity of PKH26-labeled LP4 cells, and LP11 cells were not detected under a fluorescence microscope. However, the fluorescence of LP4 cells labeled with lentivirus-GFP remained strong, and cells labeled with lentivirus-GFP were detected up to LP14 under a fluorescence microscope. Statistical analyses indicated that percentages of LP1 cells labeled with PKH26 and lentivirus-GFP were significantly higher than that of cells labeled with BrdU (p < 0.05), and that the LP4 cells were more efficiently labeled with lentivirus-GFP than with PKH26 or BrdU (p < 0.05). BrdU-, PKH26-, and lentivirus-GFP labeled LP4 cells were all differentiated to adipocytes or osteoblasts with adipogenic and osteogenic medium. No statistical significance (p > 0.05) was observed between the death rates of labeled and unlabeled cells.

CONCLUSIONS

Lentivirus-GFP is a valid method for long-term in vitro labeling, and it may be used as a long-term hUCMSC tracker following transplantation in vivo.

Therapeutic potential of umbilical cord mesenchymal stem cells with Wnt/β-catenin signaling pathway pre-activated for the treatment of diabetic wounds

The pathogenesis of diabetes mellitus wounds is complicate, and there lacks effective treatment strategies. Mesenchymal stem cells can promote wound healing. Compared with bone marrow mesenchymal stem cells, umbilical cord mesenchymal stem cells have obvious advantages in biological property. Wnts are potent regulatory molecules for stem cell turnover and skin regeneration, while Wnt signaling is not well activated in diabetic wounds. Umbilical cord mesenchymal stem cells with Wnt/β-catenin signaling pathway pre-activated have some potential in the treatment of diabetic wounds. In this paper, we review the research status as well as problems in this field.

Epimorphin-induced differentiation of human umbilical cord mesenchymal stem cells into sweat gland cells

OBJECTIVES

Mesenchymal stem cells (MSCs) have the potential for multi-directional differentiation and can be induced to differentiate into sweat gland cells under certain conditions. Epimorphin (EPM) plays an important role in the promotion of epithelial cell morphogenesis; however, its effect on sweat gland-cell differentiation of MSCs remains unknown. The purpose of this study was to investigate how EPM regulates sweat gland cell differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs).

MATERIALS AND METHODS

hUCMSCs were labeled with 5-bromo-2-deoxyuridine (BrdU) before differentiation induction; were cultured in common culture medium, conditioned medium, or EPM-conditioned medium; and then induced to differentiate into sweat gland cells. Five days after induction, the expression rates of the sweat gland-cell antigens cytokeratin 14 (CK14), cytokeratin 19 (CK19), and carcinoembryonic antigen (CEA) in hUCMSCs were detected by flow cytometry, and the messenger ribonucleic acid (mRNA) and protein levels of CK14, CK19, and CEA were determined by reverse transcription polymerase chain reaction (RT-PCR) and western blot, respectively.

RESULTS

hUCMSCs can be induced to differentiate into sweat gland cells in conditioned medium, and expression of CEA was detected by immunofluorescence assay. Flow cytometry results showed that the expression rate of the sweat gland-cell antigens CK14, CK19, and CEA in the conditioned medium were significantly lower than that in the EPM conditioned medium (p < 0.05). RT-PCR and western blot results showed that the mRNA and protein levels of CK14, CK19, and CEA in the conditioned medium were all significantly lower than that in the EPM-conditioned medium (p < 0.01).

CONCLUSIONS

These results suggest that EPM can effectively induce the differentiation of hUCMSCs into sweat gland cells.

An improved dosage regimen of sertraline hydrochloride in the treatment for premature ejaculation: an 8-week, single-blind, randomized controlled study followed by a 4-week, open-label extension study

WHAT IS KNOWN AND OBJECTIVE

This study aimed at evaluating the safety and efficacy of an improved dosage regimen of sertraline in patients with premature ejaculation (PE) and to examine whether the premature ejaculation diagnostic tool (PEDT) can be used as a measure of treatment response in these patients.

METHODS

A total of 218 PE patients were randomized into control (n = 61) and treatment (n = 157) groups to receive mycelium of cordyceps sinensis C4 and sertraline 50 mg daily for 8 weeks, respectively. Following this blinded stage, sixty-three patients chose to take sertraline 100 mg daily for an additional 4-week period, and 80 other patients continued treatment with sertraline 50 mg. Main outcome measures include intravaginal ejaculatory latency time (IELT), PEDT score and Clinical Global Impression of Change (CGIC) score.

RESULTS

At weeks 4 and 8, mean IELT of patients who subsequently chose to take 100 mg of sertraline was significantly lower than that of patients who continued taking 50 mg of sertraline, although the IELT value was comparable between the two groups of patients at baseline. However, with an additional 4-week treatment, the mean IELT increased significantly more in the 100-mg group than in the 50-mg continuation group. Similar results were also obtained in the analyses of the PEDT and CGIC scores. Both regimens were well tolerated, and relapse rate did not differ significantly between the two groups.

WHAT IS NEW AND CONCLUSION

These findings suggest that PE patients not responding to an 8-week treatment with sertraline 50 mg can benefit from an additional 4-week treatment with sertraline 100 mg and that the PEDT may be a valid measure of treatment response in PE patients.

Biomechanical changes in the pharynx and upper esophageal sphincter after modified balloon dilatation in brainstem stroke patients with dysphagia

BACKGROUND

Few studies have investigated the biomechanical changes in the upper esophageal sphincter (UES) and pharyngeal function after successful dilatation therapy for dysphagia. Using high-resolution manometry (HRM), we examined the biomechanical properties of swallowing in brainstem stroke patients with dysphagia following modified balloon dilation therapy.

METHODS

30 brainstem stroke patients with dysphagia were included. Patients in the experimental group received 3 weeks of modified balloon dilatation treatment and regular dysphagia therapy. Patients in the control group received 3 weeks of regular dysphagia therapy only. Efficacy of treatment was evaluated before and following intervention. Functional oral intake was measured using the Functional Oral Intake Scale (FOIS). Pharyngeal maximum pressures and duration, UES residual pressure and duration during swallowing were measured using HRM.

KEY RESULTS

In the experimental group, the feeding tube was able to be removed in 12 of 15 patients, vs 2 of 15 patients in the control group. The experimental group had 4-point median improvement, while control groups only had 1-point improvement in FOIS scores. In the experimental group, posttreatment UES relaxation and pharyngeal propulsion were both significantly improved for the three materials (p < 0.05) and UES resting pressure approximated normal. In the control group, pharyngeal propulsion was improved for water and thick liquids (p < 0.05) but not for paste material; there was no improvement in posttreatment UES relaxation for all three materials (p > 0.05).

CONCLUSIONS & INFERENCES

Dysphagia therapy with modified dilatation improved UES relaxation, strengthened pharyngeal propulsion, restored UES resting pressure and improved functional oral intake to a greater extent than regular therapy alone.

Short hairpin RNA targeting of fibroblast activation protein inhibits tumor growth and improves the tumor microenvironment in a mouse model

Fibroblast activation protein (FAP) is a specific serine protease expressed in tumor stroma proven to be a stimulatory factor in the progression of some cancers. The purpose of this study was to investigate the effects of FAP knockdown on tumor growth and the tumor microenvironment. Mice bearing 4T1 subcutaneous tumors were treated with liposome-shRNA complexes targeting FAP. Tumor volumes and weights were monitored, and FAP, collagen, microvessel density (MVD), and apoptosis were measured. Our studies showed that shRNA targeting of FAP in murine breast cancer reduces FAP expression, inhibits tumor growth, promotes collagen accumulation (38%), and suppresses angiogenesis (71.7%), as well as promoting apoptosis (by threefold). We suggest that FAP plays a role in tumor growth and in altering the tumor microenvironment. Targeting FAP may therefore represent a supplementary therapy for breast cancer. [BMB Reports 2013; 46(5): 252-257]

Dog safety in rural China: children's sources of safety information and effect on knowledge, attitudes, and practices

Dog bites are a significant pediatric public health challenge in rural China. This study evaluated the effect of various sources of dog-safety information on children's knowledge, attitudes, beliefs and practices with dogs. A total of 1925 children (grade 3-6) between 6 and 15 years old in four rural regions across China participated between May and September 2012. Results showed that teachers and especially parents were effective information sources for children to learn about dog safety. Learning from peers and children teaching themselves were ineffective education strategies. Multi-source learning (from both parents and teachers) did not differ from single-source learning (from parents but not teachers) but did exceed learning from teachers but not parents or no learning from adults. Older age was associated with greater safety knowledge but also riskier practices with dogs. Girls generally held more safety knowledge, less risky attitudes/beliefs and safer practices than boys. Neither age nor gender interacted with information sources on outcome measures. In conclusion, parents appear to play a major role in educating children in rural China on dog safety. Future dog safety interventions might focus on changing cognition and behavior as well as delivering basic knowledge to youth through teachers and especially parents.

Predicting skin permeability from complex chemical mixtures: incorporation of an expanded QSAR model

Quantitative structure-activity relationship (QSAR) models have been widely used to study the permeability of chemicals or solutes through skin. Among the various QSAR models, Abraham's linear free-energy relationship (LFER) model is often employed. However, when the experimental conditions are complex, it is not always appropriate to use Abraham's LFER model with a single set of regression coefficients. In this paper, we propose an expanded model in which one set of partial slopes is defined for each experimental condition, where conditions are defined according to solvent: water, synthetic oil, semi-synthetic oil, or soluble oil. This model not only accounts for experimental conditions but also improves the ability to conduct rigorous hypothesis testing. To more adequately evaluate the predictive power of the QSAR model, we modified the usual leave-one-out internal validation strategy to employ a leave-one-solute-out strategy and accordingly adjust the Q(2) LOO statistic. Skin permeability was shown to have the rank order: water > synthetic > semi-synthetic > soluble oil. In addition, fitted relationships between permeability and solute characteristics differ according to solvents. We demonstrated that the expanded model (r(2) = 0.70) improved both the model fit and the predictive power when compared with the simple model (r(2) = 0.21).

Genome-wide association study in a Chinese population identifies a susceptibility locus for type 2 diabetes at 7q32 near PAX4

AIMS/HYPOTHESIS

Most genetic variants identified for type 2 diabetes have been discovered in European populations. We performed genome-wide association studies (GWAS) in a Chinese population with the aim of identifying novel variants for type 2 diabetes in Asians.

METHODS

We performed a meta-analysis of three GWAS comprising 684 patients with type 2 diabetes and 955 controls of Southern Han Chinese descent. We followed up the top signals in two independent Southern Han Chinese cohorts (totalling 10,383 cases and 6,974 controls), and performed in silico replication in multiple populations.

RESULTS

We identified CDKN2A/B and four novel type 2 diabetes association signals with p < 1 × 10(-5) from the meta-analysis. Thirteen variants within these four loci were followed up in two independent Chinese cohorts, and rs10229583 at 7q32 was found to be associated with type 2 diabetes in a combined analysis of 11,067 cases and 7,929 controls (p meta = 2.6 × 10(-8); OR [95% CI] 1.18 [1.11, 1.25]). In silico replication revealed consistent associations across multiethnic groups, including five East Asian populations (p meta = 2.3 × 10(-10)) and a population of European descent (p = 8.6 × 10(-3)). The rs10229583 risk variant was associated with elevated fasting plasma glucose, impaired beta cell function in controls, and an earlier age at diagnosis for the cases. The novel variant lies within an islet-selective cluster of open regulatory elements. There was significant heterogeneity of effect between Han Chinese and individuals of European descent, Malaysians and Indians.

CONCLUSIONS/INTERPRETATION

Our study identifies rs10229583 near PAX4 as a novel locus for type 2 diabetes in Chinese and other populations and provides new insights into the pathogenesis of type 2 diabetes.

Role of mitogen-activated protein kinase cascades in 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced apoptosis in neuronal pheochromocytoma cells

Mitogen-activated protein kinases (MAPKs) are involved in neuronal death caused by many cytotoxins. Conventional MAPKs consist of three family members: extracellular signal-regulated kinase-1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38. It has been originally shown that ERK1/2 is important for cell survival, whereas JNK and p38 are deemed stress responsive and thus involved in apoptosis. However, information describing the role of MAPKs in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced neurotoxicity is insufficient. The aim of this study was to identify the role of MAPK cascades in TCDD-induced neurotoxicity using differentiated pheochromocytoma (PC12) cells as a model for neuronal cells. Cell viability assay, terminal deoxynucleotidyl transferase dUTP nick-end labeling assay and flow cytometry analysis showed that TCDD attenuated cell viability with a dose- and time-dependent manner and significantly induced apoptosis in primary cortical neurons and PC12 cells. Western blot analysis indicated that TCDD markedly activated the expression of ERK1/2, JNK and p38 in TCDD-treated PC12 cells. Furthermore, PD98059 (ERK1/2 inhibitor), SP600125 (JNK inhibitor) and SB202190 (p38 inhibitor) notably blocked the effect of TCDD on cell apoptosis. Based on the findings above, it is concluded that the activation of MAPK signaling pathways may be associated with TCDD-mediated neuronal apoptosis.

Web-based distance learning for nurse education: a systematic review

BACKGROUND

Web-based distance learning is considered a promising approach to replace or supplement conventional nursing instruction. However, no systematic review has been seen to explore the effect of web-based distance education in nursing.

AIM

To examine the efficacy of the web-based distance education for nursing students and employed nurses.

METHODS

A systematic review of randomized controlled studies was undertaken. Multiple search strategies were performed in PubMed and Embase until July 2012. Two reviewers independently selected trials, conducted quality critical appraisal, and extracted the data from the included studies.

RESULTS

Nine randomized controlled trials met inclusion criteria, among which five studies were rated as A quality level, and the other four studies as B quality level. The results showed that web-based distance learning has produced equivalent or better effects in knowledge acquisition. For nursing skill performance, four studies revealed a positive role for the new teaching mode, and one study showed a negative viewpoint. This review also demonstrated that participants generally accepted web-based education with high satisfaction rates. Two studies reported a more positive trend for self-efficacy in performing nursing skills in the experiment group compared with control group. Some negative feedbacks were also expressed.

CONCLUSION

Web-based education has encouraging effects in improving both participants' knowledge and skills performance, and in enhancing self-efficacy in performing nursing skills, with a high satisfaction rate expressed by participants. More rigorous experimental studies are advocated.

Pharmacological reduction of NEFA restores the efficacy of incretin-based therapies through GLP-1 receptor signalling in the beta cell in mouse models of diabetes

AIMS/HYPOTHESIS

Type 2 diabetes mellitus is associated with reduced incretin effects. Although previous studies have shown that hyperglycaemia contributes to impaired incretin responses in beta cells, it is largely unknown how hyperlipidaemia, another feature of type 2 diabetes, contributes to impaired glucagon-like peptide 1 (GLP-1) response. Here, we investigated the effects of NEFA on incretin receptor signalling and examined the glucose-lowering efficacy of incretin-based drugs in combination with the lipid-lowering agent bezafibrate.

METHODS

We used db/db mice to examine the in vivo efficacy of the treatment. Beta cell lines and mouse islets were used to examine GLP-1 and glucose-dependent insulinotropic peptide receptor signalling.

RESULTS

Palmitate treatment decreased Glp1r expression in rodent insulinoma cell lines and isolated islets. This was associated with impairment of the following: GLP-1-stimulated cAMP production, phosphorylation of cAMP-responsive elements binding protein (CREB) and insulin secretion. In insulinoma cell lines, the expression of exogenous Glp1r restored cAMP production and the phosphorylation of CREB. Treatment with bezafibrate in combination with des-fluoro-sitagliptin or exendin-4 led to more robust glycaemic control, associated with improved islet morphology and beta cell mass in db/db mice.

CONCLUSIONS/INTERPRETATION

Elevated NEFA contributes to impaired responsiveness to GLP-1, partially through downregulation of GLP-1 receptor signalling. Improvements in lipid control in mouse models of obesity and diabetes increase the efficacy of incretin-based therapy.

A cortical folding model incorporating stress-dependent growth explains gyral wavelengths and stress patterns in the developing brain

In humans and many other mammals, the cortex (the outer layer of the brain) folds during development. The mechanics of folding are not well understood; leading explanations are either incomplete or at odds with physical measurements. We propose a mathematical model in which (i) folding is driven by tangential expansion of the cortex and (ii) deeper layers grow in response to the resulting stress. In this model the wavelength of cortical folds depends predictably on the rate of cortical growth relative to the rate of stress-induced growth. We show analytically and in simulations that faster cortical expansion leads to shorter gyral wavelengths; slower cortical expansion leads to long wavelengths or even smooth (lissencephalic) surfaces. No inner or outer (skull) constraint is needed to produce folding, but initial shape and mechanical heterogeneity influence the final shape. The proposed model predicts patterns of stress in the tissue that are consistent with experimental observations.

Preparation of microencapsulated VEGF gene-modified human umbilical cord mesenchymal stem cells and in vitro culture

BACKGROUND AND OBJECTIVES

The application of microencapsulated stem cells has been shown to have many advantages in various fields of medical research. However, optimal modes for preparation of microencapsulate stem cells need to be improved, and expression and release of products of microencapsulated gene modified stem cells need to be studied in vitro.

AIM OF THE STUDY

To explore the optimal parameters when preparing microencapsulated stem cells, and to investigate the effect of microencapsulation on growth, secretion, and metabolism of genetically modified human Umbilical Cord Mesenchymal Stem Cells (hUCMSCs).

MATERIALS AND METHODS

In this study, the parameters of preparation were regulated by observing the microcapsule shape and size. Live/dead cell viability kits and fluorescein isothiocyanate-labeled dextrans (FD) were used to detect the microencapsulated cell viability, and the permeability of microcapsules, respectively. Vascular endothelial growth factor (VEGF) production in the supernatant of microencapsulated and non-microencapsulated VEGF gene-modified hUCMSCs cultures was measured by ELISA.

RESULTS

The optimal parameters of preparing microcapsules were regulated as followed: bolus velocity was 6 ml/h, and airflow velocity was 3 L/min. The morphology of microcapsules was a spherical structure with a diameter of 450 ± 30 µm. More than 90% of the cells were viable after 21 days of culture. Low and middle molecular weight FD was able to pass through the microcapsules; however, high molecular weight FD was not. Also, the VEGF concentration in microencapsulated and non-microencapsulated cell culture supernatants exhibited no significant difference at each time point.

CONCLUSIONS

Microencapsulated stem cells can be ideally prepared via specifically regulated preparation. Lastly, microencapsulation does not alter growth, secretion, and metabolism of the genetically modified hUCMSCs.

Selection of appropriate training and validation set chemicals for modelling dermal permeability by U-optimal design

Quantitative structure-activity relationship (QSAR) models are being used increasingly in skin permeation studies. The main idea of QSAR modelling is to quantify the relationship between biological activities and chemical properties, and thus to predict the activity of chemical solutes. As a key step, the selection of a representative and structurally diverse training set is critical to the prediction power of a QSAR model. Early QSAR models selected training sets in a subjective way and solutes in the training set were relatively homogenous. More recently, statistical methods such as D-optimal design or space-filling design have been applied but such methods are not always ideal. This paper describes a comprehensive procedure to select training sets from a large candidate set of 4534 solutes. A newly proposed 'Baynes' rule', which is a modification of Lipinski's 'rule of five', was used to screen out solutes that were not qualified for the study. U-optimality was used as the selection criterion. A principal component analysis showed that the selected training set was representative of the chemical space. Gas chromatograph amenability was verified. A model built using the training set was shown to have greater predictive power than a model built using a previous dataset [1].

Reachability analysis of real-time systems using time Petri nets

Time Petri nets (TPNs) are a popular Petri net model for specification and verification of real-time systems. A fundamental and most widely applied method for analyzing Petri nets is reachability analysis. The existing technique for reachability analysis of TPNs, however, is not suitable for timing property verification because one cannot derive end-to-end delay in task execution, an important issue for time-critical systems, from the reachability tree constructed using the technique. In this paper, we present a new reachability based analysis technique for TPNs for timing property analysis and verification that effectively addresses the problem. Our technique is based on a concept called clock-stamped state class (CS-class). With the reachability tree generated based on CS-classes, we can directly compute the end-to-end time delay in task execution. Moreover, a CS-class can be uniquely mapped to a traditional state class based on which the conventional reachability tree is constructed. Therefore, our CS-class-based analysis technique is more general than the existing technique. We show how to apply this technique to timing property verification of the TPN model of a command and control (C2) system.

Study of HIV/AIDS-related knowledge among junior high-school students in Shanghai, China

The aim of this study was to assess the HIV/AIDS-related knowledge among junior high-school students in Shanghai, China, and the factors influencing this knowledge. A cross-sectional study was conducted in 20 middle schools of two districts by a cluster-stratified selection procedure in Shanghai, China. The 2432 sampled students, aged from 11.1 to 16.7 years, completed a self-administered questionnaire of HIV/AIDS prevention. The results showed that the overall correct rate of HIV/AIDS-related knowledge was 62%. Using multivariable logistic regression analysis, we found that the main factors influencing HIV/AIDS-related knowledge among junior high school students were the type of school (odds ratio [OR] = 1.641), age (OR = 1.727), whether the student was a single child in the family (OR = 1.389), whether the student had previous HIV/AIDS-related education experience (OR = 2.003) and whether the student had ever discussed HIV/AIDS with their parents (OR = 1.282). The results indicate that HIV/AIDS-related knowledge among Shanghai junior high school students is not high enough, and more attention needs to be paid to enhance HIV/AIDS-related knowledge, especially among younger students from common type schools without HIV/AIDS-related education experience. We encourage Chinese parents to get involved in their children's HIV/AIDS prevention education.

Hypomethylation upregulates the expression of CD30 in lymphoma induced by Marek's disease virus

Epigenetic modification is widely known to be involved in embryo development, aging, tumorigenesis, and many complex diseases. Both hypermethylation of CpG islands at the gene promoters and global hypomethylation are involved in the initiation and progression of carcinogenesis. However, only a small portion of hypomethylation occurs at gene promoters and leads to the overexpression of certain oncogenes. To determine whether DNA methylation plays a role in tumorigenesis of Marek's disease, we selected one putative oncogene and 8 tumor suppressor genes from the gene expression profile for the analysis of DNA methylation variation. Four normal spleen tissues and 4 Marek's disease virus-infected tumor spleen tissues were collected, and the methylation level of the promoter region of each gene was analyzed using MassARRAY. As a result, the promoter region of CD30 was hypomethylated and displayed a significantly higher expression in Marek's disease virus-infected tumor spleen tissues compared with normal ones (P < 0.05). In neoplastic cells, CD30 was known to promote the survival and proliferation of T-cell lymphomas. This result suggests that activation of CD30 is possibly associated with the tumorigenesis of Marek's disease.

Clinical Analysis of 50 Chinese Patients with Aqueous Misdirection Syndrome: A Retrospective Hospital-Based Study

OBJECTIVES: To evaluate the efficacy of treatments for aqueous misdirection syndrome and explore possible risk factors influencing prognosis. METHODS: Data including demographics, initial clinical characteristics and ocular outcomes at follow-up were collected for patients treated for aqueous misdirection syndrome. Main outcome measures were: best-corrected visual acuity (BCVA); intraocular pressure (IOP); number of antiglaucoma medications; recurrence; complications. RESULTS: Data were available for 50 patients (57 eyes). Final mean BCVA improved significantly and correlated with baseline BCVA (mean follow-up, 34.47 ± 28.65 months). Final mean IOP and mean number of antiglaucoma medications were significantly reduced. Treatment failure rates were higher in patients with significantly higher IOP at baseline and/or shorter axial length. Following pars plana vitrectomy (PPV), recurrence occurred in two of 10 pseudophakic and one of 40 phakic eyes; complications were observed in 12/50 eyes (choroidal detachment, corneal decompensation, retinal detachment, vitreous haemorrhage, hyphaema). CONCLUSIONS: PPV and laser treatments, augmented by pharmacotherapy, were effective in treating aqueous misdirection syndrome. Surgical intervention should be undertaken early in eyes with higher baseline IOP and/or shorter axial length. Total vitrectomy— zonulectomy—iridectomy is a potential approach for recalcitrant cases.

Response characteristics of Scirpus trioueter and its rhizosphere to pyrene contaminated soils at different growth stages

Scirpus triqueter (Triangular club-rush), a typical wetland species, is used to study the response characteristics to pyrene. A pot experiment was conducted to investigate the growth parameters (height, diameter, shoot number, total volume, underground biomass, above-ground biomass and total biomass), and enzymes (catalase and superoxide dismutase) of S. triqueter. The characteristics of soil enzymes (catalase and polyphenol oxidase) and microorganisms (bacteria and fungi) were also assessed after pyrene treatment. Elevated pyrene concentration (80 mgkg(-1)) in the soil reduced the shoot number and biomass significantly, especially at the early growth stage. In root tissue, the enzyme catalase was activated at 80 mgkg(-1) of pyrene. Compared to roots, shoots had higher enzyme activities. Catalase activities in the rhizosphere increased throughout the growth period of S. triqueter. Polyphenol oxidase activities in the rhizosphere were higher than those in the bulk soil and unplanted soil. The populations of bacteria (total bacteria, pyrene-tolerant bacteria, and actinomyces) and fungi decreased under the stress of high pyrene concentration, while that of pyrene-tolerant bacteria increased with the increasing pyrene concentration. The presence of pyrene did not benefit the growth of S. triqueter. S. triqueter and soil enzymes varied within the growth stages. The presence of S. triqueter could improve the activity of soil enzymes and facilitate the propagation of microorganisms which could help eliminate pyrene contamination.

Mesenchymal stem cells derived from human induced pluripotent stem cells modulate T-cell phenotypes in allergic rhinitis

BACKGROUND

Human induced pluripotent stem cells (iPSCs) possess remarkable self-renewal capacity and the potential to differentiate into novel cell types, such as mesenchymal stem cells (MSCs). iPSC-MSCs have been shown to enhance tissue regeneration and attenuate tissue ischaemia; however, their contribution to the immune regulation of Th2-skewed allergic rhinitis (AR) and asthma remains unclear.

OBJECTIVE

This study compared the immunomodulatory effects of iPSC-MSCs and bone marrow-derived MSCs (BM-MSCs) on lymphocyte proliferation, T-cell phenotypes and cytokine production in peripheral blood mononuclear cells (PBMCs) in patients with AR, and investigated the possible molecular mechanisms underlying the immunomodulatory properties of iPSC-MSCs.

METHODS

In co-cultures of PBMCs with iPSC-MSCs or BM-MSCs, lymphocyte proliferation was evaluated using 3H-thymidine (3H-TdR) uptake, carboxyfluorescein diacetate, succinimidyl ester (CFDA-SE) assays; the regulatory T-cell (Treg) phenotype was determined by flow cytometry, and cytokine levels were measured using an enzyme-linked immunosorbent assay. The immunomodulatory properties of both MSCs were further evaluated using NS398 and transwell experiments.

RESULTS

Similar to BM-MSCs, we determined that iPSC-MSCs significantly inhibit lymphocyte proliferation and promote Treg response in PBMCs (P < 0.05). Accordingly, the cytokine milieu (IFN-γ, IL-4, IL-5, IL-10 and IL-13) in the supernatants of PBMCs changed significantly (P < 0.05). The immunomodulatory properties of iPSC-MSCs and BM-MSCs were associated with prostaglandin E2 (PGE2) production and cell-cell contact.

CONCLUSIONS

These data demonstrate that iPSC-MSCs are capable of modulating T-cell phenotypes towards Th2 suppression through inducing Treg expansion, suggesting that iPSC-MSCs can be used as an alternative candidate to adult MSCs to treat allergic airway diseases.

Mesenchymal stem cells derived from human induced pluripotent stem cells modulate T-cell phenotypes in allergic rhinitis

Background

Human induced pluripotent stem cells (iPSCs) possess remarkable self-renewal capacity and the potential to differentiate into novel cell types, such as mesenchymal stem cells (MSCs). iPSC-MSCs have been shown to enhance tissue regeneration and attenuate tissue ischaemia; however, their contribution to the immune regulation of Th2-skewed allergic rhinitis (AR) and asthma remains unclear.

Objective

This study compared the immunomodulatory effects of iPSC-MSCs and bone marrow-derived MSCs (BM-MSCs) on lymphocyte proliferation, T-cell phenotypes and cytokine production in peripheral blood mononuclear cells (PBMCs) in patients with AR, and investigated the possible molecular mechanisms underlying the immunomodulatory properties of iPSC-MSCs.

Methods

In co-cultures of PBMCs with iPSC-MSCs or BM-MSCs, lymphocyte proliferation was evaluated using 3H-thymidine (3H-TdR) uptake, carboxyfluorescein diacetate, succinimidyl ester (CFDA-SE) assays; the regulatory T-cell (Treg) phenotype was determined by flow cytometry, and cytokine levels were measured using an enzyme-linked immunosorbent assay. The immunomodulatory properties of both MSCs were further evaluated using NS398 and transwell experiments.

Results

Similar to BM-MSCs, we determined that iPSC-MSCs significantly inhibit lymphocyte proliferation and promote Treg response in PBMCs (P < 0.05). Accordingly, the cytokine milieu (IFN-γ, IL-4, IL-5, IL-10 and IL-13) in the supernatants of PBMCs changed significantly (P < 0.05). The immunomodulatory properties of iPSC-MSCs and BM-MSCs were associated with prostaglandin E2 (PGE2) production and cell–cell contact.

Conclusions

These data demonstrate that iPSC-MSCs are capable of modulating T-cell phenotypes towards Th2 suppression through inducing Treg expansion, suggesting that iPSC-MSCs can be used as an alternative candidate to adult MSCs to treat allergic airway diseases.

BLyS expression and JNK activation may form a feedback loop to promote survival and proliferation of multiple myeloma cells

B-Lymphocyte stimulator (BLyS), a member of tumor necrosis factor superfamily, is a potent co-activator of B cells in vitro, and in vivo induces B cell proliferation and immunoglobulin secretion. Multiple myeloma (MM) is an incurable malignancy of terminally differentiated B cells (plasma cells). Previous studies have well ascertained that BLyS plays an important contributory role in the pathogenesis and propagation of multiple myeloma by virtue of its ability to promote B cell survival, expansion, and differentiation. However, the intracellular signaling of BLyS in human MM cells remains undefined. This study was designed to see whether there was interaction between MAPK signaling pathway and BLyS expression. It was found that the active protein p-JNK was expressed in KM3, U266 and PBMCs of MM patients, and that the expression of BLyS could be changed by JNK pathway activator and inhibitor. In addition, recombinant BLyS activated JNK pathway, while BLyS siRNA treatment inhibited the activation of JNK pathway. The level of BLyS expression and the activation of JNK pathway were positively correlated. These findings suggest that JNK activation and BLyS expression in MM cells may form a positive feedback loop that promotes the survival and proliferation of MM cells, and these may shed some light on the pathogenesis and treatment of MM.

Three dimensionality and orbital characters of the Fermi surface in (Tl,Rb)(y)Fe(2-x)Se2

We report a comprehensive angle-resolved photoemission spectroscopy study of the tridimensional electronic bands in the recently discovered Fe selenide superconductor ((Tl,Rb)(y)Fe(2-x)Se2 (T(c)=32  K). We determined the orbital characters and the k(z) dependence of the low energy electronic structure by tuning the polarization and the energy of the incident photons. We observed a small 3D electron Fermi surface pocket near the Brillouin zone center and a 2D like electron Fermi surface pocket near the zone boundary. The photon energy dependence, the polarization analysis and the local-density approximation calculations suggest a significant contribution from the Se 4p(z) and Fe 3d(xy) orbitals to the small electron pocket. We argue that the emergence of Se 4p(z) states might be the cause of the different magnetic properties between Fe chalcogenides and Fe pnictides.

Comparison of the diagnostic value of 3-deoxy-3-18F-fluorothymidine and 18F-fluorodeoxyglucose positron emission tomography/computed tomography in the assessment of regional lymph node in thoracic esophageal squamous cell carcinoma: a pilot study

We used pathological examination as golden standard to determine whether 3-deoxy-3-(18)F-fluorothymidine positron emission tomography/computed tomography (FLT PET/CT) can detect regional lymph node metastasis in untreated thoracic esophageal squamous cell carcinoma and additionally performed (18)F-fluorodeoxyglucose (FDG) PET/CT for direct comparison with that of FLT. Twenty-two patients with thoracic esophageal squamous cell carcinoma underwent dual-tracer PET/CT examinations before surgery. The results of reviewing CT images and side-by-side FDG PET and FLT PET images for the diagnosis of locoregional lymph node metastasis were compared prospectively in relation to pathologic findings. All patients underwent esophagectomy and lymphadenectomy. Pathologic examination confirmed nodes positive for metastasis in 16 patients and 47 of 424 excised nodes. The uptake of FDG (median SUVmax, 5.4; range, 2.4-10.6) in locoregional lymph nodes metastases was significantly higher than that of FLT (median SUVmax, 2.8; range, 1.3-4.6). There were 14 false-positive nodes in FDG PET/CT and only 3 in FLT PET/CT; 8 false-negative nodes in FDG PET/CT, while there were 12 false negative nodes in FLT PET/CT. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of FLT PET/CT were 74.47%, 99.20%, 96.46%, 92.11%, and 96.89%, respectively, whereas those of FDG PET/CT were 82.98%, 96.29%, 94.81%, 82.98%, and 96.29%, respectively. P-values were 0.450, 0.014, 0.313, 0.050, and 0.555, respectively. FLT uptake in regional lymph nodes of esophageal carcinoma is significantly lower compared with FDG uptake. FLT PET/CT has fewer false-positive findings and higher specificity compared with FDG PET/CT.

Addressing different biases in analysing drug use on cancer risk in diabetes in non-clinical trial settings--what, why and how?

Motivated by recent reports on associations between diabetes and cancer, many researchers have used administrative databases to examine risk association of cancer with drug use in patients with diabetes. Many of these studies suffered from major biases in study design and data analysis, which can lead to erroneous conclusions if these biases are not adjusted. This article discusses the sources and impacts of these biases and methods for correction of these biases. To avoid erroneous results, this article suggests performing sensitivity and specificity analysis as well as using a drug with a known effect on an outcome to ascertain the validity of the proposed methods. Using the Hong Kong Diabetes Registry, we illustrated the impacts of biases of drug use indication and prevalent user by examining the effects of statins on cardiovascular disease. We further showed that 'immortal time bias' may have a neutral impact on the estimated drug effect if the hazard is assumed to be constant over time. On the contrary, adjustment for 'immortal time bias' using time-dependent models may lead to misleading results biased towards against the treatment. However, artificial inclusion of immortal time in non-drug users to correct for immortal time bias may bias the result in favour of the therapy. In conclusion, drug use indication bias and prevalent user bias but not immortal time bias are major biases in the design and analysis of drug use effects among patients with diabetes in non-clinical trial settings.

Ghrelin contributes to derangements of glucose metabolism induced by rapamycin in mice

AIMS/HYPOTHESIS

Rapamycin impairs glucose tolerance and insulin sensitivity. Our previous study demonstrated that rapamycin significantly increases the production of gastric ghrelin, which is critical in the regulation of glucose metabolism. Here, we investigated whether ghrelin contributes to derangements of glucose metabolism induced by rapamycin.

METHODS

The effects of rapamycin on glucose metabolism were examined in mice receiving ghrelin receptor antagonist or with Ghsr1a gene knockout. Changes in GLUT4, c-Jun N-terminal kinase (JNK) and phosphorylated ribosomal protein S6 (pS6) were investigated by immunofluorescent staining or western blotting. Related hormones were detected by radioimmunoassay kits.

RESULTS

Rapamycin impaired glucose metabolism and insulin sensitivity not only in normal C57BL/6J mice but also in both obese mice induced by a high fat diet and db/db mice. This was accompanied by elevation of plasma acylated ghrelin. Rapamycin significantly increased the levels of plasma acylated ghrelin in normal C57BL/6J mice, high-fat-diet-induced obese mice and db/db mice. Elevation in plasma acylated ghrelin and derangements of glucose metabolism upon administration of rapamycin were significantly correlated. The deterioration in glucose homeostasis induced by rapamycin was blocked by D: -Lys3-GHRP-6, a ghrelin receptor antagonist, or by deletion of the Ghsr1a gene. Ghrelin receptor antagonism and Ghsr1a knockout blocked the upregulation of JNK activity and downregulation of GLUT4 levels and translocation in the gastrocnemius muscle induced by rapamycin.

CONCLUSIONS/INTERPRETATION

The current study demonstrates that ghrelin contributes to derangements of glucose metabolism induced by rapamycin via altering the content and translocation of GLUT4 in muscles.