Vertically integrated translational studies of PDX1 as a therapeutic target for pancreatic cancer via a novel bifunctional RNAi platform

RNA interference (RNAi) represents a powerful, new tool for scientific investigation as well as a promising new form of targeted gene therapy, with applications currently in clinical trials. Bifunctional short hairpin RNA (shRNA) are synthetic RNAi molecules, engineered to utilize multiple endogenous RNAi pathways to specifically silence target genes. Pancreatic and duodenal homeobox 1 (PDX1) is a key regulator of pancreatic development, β-cell differentiation, normal β-cell function and pancreatic cancer. Our aim is to review the process of identifying PDX1 as a specific, potential RNAi target in pancreatic cancer, as well as the underlying mechanisms and various forms of RNAi, with subsequent testing and development of PDX1-targeted bifunctional shRNA therapy.

The DNA double-strand break response is abnormal in myeloblasts from patients with therapy-related acute myeloid leukemia

The complex chromosomal aberrations found in therapy-related acute myeloid leukemia (t-AML) suggest that the DNA double-strand break (DSB) response may be altered. In this study we examined the DNA DSB response of primary bone marrow cells from t-AML patients and performed next-generation sequencing of 37 canonical homologous recombination (HR) and non-homologous end-joining (NHEJ) DNA repair genes, and a subset of DNA damage response genes using tumor and paired normal DNA obtained from t-AML patients. Our results suggest that the majority of t-AML patients (11 of 15) have tumor-cell intrinsic, functional dysregulation of their DSB response. Distinct patterns of abnormal DNA damage response in myeloblasts correlated with acquired genetic alterations in TP53 and the presence of inferred chromothripsis. Furthermore, the presence of trisomy 8 in tumor cells was associated with persistently elevated levels of DSBs. Although tumor-acquired point mutations or small indels in canonical HR and NHEJ genes do not appear to be a dominant means by which t-AML leukemogenesis occurs, our functional studies suggest that an abnormal response to DNA damage is a common finding in t-AML.

Practising case-based learning in oral medicine for dental students in China

INTRODUCTION

Teacher-centred education dominates dental education in China. Student-centred education has recently been introduced in the School of Stomatology, Wuhan University, and the effectiveness of such methods needs to be tested. The purpose of this study is to compare the learning outcomes of case-based learning (CBL) and lecture-based education (LBE) in an oral medicine curriculum.

MATERIALS AND METHODS

We chose oral leukoplakia as the learning subject for dental students. Forty fourth-year dental students participated in the study. First, they were presented to basic knowledge of oral leukoplakia and related oral mucosal diseases. Then, they were divided into a CBL group (n=20) and an LBE group (n=20) by random numbers. The groups experienced the remaining course in separate groups. All students answered a questionnaire on their satisfaction with the education and the same standardised written test to analyse their learning outcomes.

RESULTS

Both CBL and LBE courses were well accepted by students according to the satisfactory scores of the questionnaire. The test scores of the CBL group (90.00±6.69) were significantly higher (P<0.01) than those of the LBE group (83.00±6.77). The percentage of high test score (test score≥85) of the CBL group (85%) was also significantly higher (P<0.01) than that of the LBE group (45%).

CONCLUSIONS

In this example, CBL was found to be more effective than LBE to teach dental students. These findings suggest that CBL should be added in our future oral medicine curriculum for dental students.

Sex differences in stroke case fatality: a meta-analysis

BACKGROUND

In recent years, there were great controversies about gender disparities in stroke outcome. The study was aimed to investigate sex differences in stroke case fatality on all published studies based in a comprehensive meta-analysis.

METHODS

A systematic search of Pubmed, EMBASE, SCOPUS, ISI Web of Science, and Cochrane Library was conducted for the included papers between 1992 and 2009. For the pooled group and subgroup analysis, fixed effects or random effects model were used to find sex differences in case fatality of stroke with a Mantel-Haenszel method. Meta-regression analysis was performed to study methodological heterogeneity.

RESULTS

Thirty-six population-based studies, together with three randomized clinical trials (RCTs), were included in the present study. For the pooled group, there was an overall hazard risk of 1.13 for women compared with men. A hazard risk of 1.27 was observed for women in RCTs subgroup and 1.12 for women in population-based subgroup. The regression analysis found no significant correlation between methodological variables and heterogeneity.

CONCLUSIONS

Due to the limited data about sex differences in stroke case fatality, the findings should be treated cautiously as preliminary. More large multicenter clinical trials should be performed to verify the reliability of the results.

Alterations of the default mode network in functional dyspepsia patients: a resting-state fmri study

BACKGROUND

Increasing brain imaging studies have emphasized the role of regional brain activity abnormalities in functional dyspepsia (FD) during the resting state. The goal of this study was to investigate the default mode network (DMN) in FD patients and healthy controls (HCs).

METHODS

Resting-state functional magnetic resonance imaging (fMRI) scanning was carried out on 49 patients and 39 HCs. Independent component analysis (ICA) was used to isolate the DMN in each subject. Group topography of the DMN was compared to study significant alteration in FD. A correlation analysis was then performed in the FD group to investigate the effects of symptom severity and the psychological factors on the DMN.

KEY RESULTS

Significant spatial differences with the DMN in FD patients, compared with HCs, were mainly found in the dorsomedial prefrontal cortex (dmPFC), ventromedial prefrontal cortex (vmPFC), orbitofrontal cortex (OFC), pregenual anterior cingulate cortex (pACC), thalamus, parahippocampal gyrus, precuneus, parietal cortex, and temporal pole. Meanwhile, Nepean Dyspepsia Index (NDI) scores were positively correlated with the pACC, and was negative correlated with the OFC. However, both the Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) scores were not correlated with any regions of interest showing differences between the FD patients and the HCs.

CONCLUSIONS & INFERENCES

These findings suggested that the DMN might indeed undergo dysfunctional changes due to the abnormal persistent activity in FD patients. To a certain extent, the changes in the DMN were related to the FD-related symptom severity.

Quantitative trait loci for morphometric body measurements of the hybrids of silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis)

Quantitative trait loci (QTL) for 11 morphometric body measurements of the hybrids of silver (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) including body weight (BW), standard length (SL), body depth (BD), body thickness (BT), head length (HL), head depth (HD), length of ventral keel (LVK), length of pectoral fin (Lpec), length of pelvic fin (Lpel), length of caudal fin (Lcau) and space between pectoral and pelvic fins (SPP) were located on the sex average microsatellite linkage map constructed using the hybrids of a female bighead and a male silver carp, on which 15 microsatellites were newly mapped. One locus was found to be responsible for BW, LV K and SPP, respectively. As many as 6 loci were found to be responsible for HD. The variances of remaining traits were partitioned by different numbers of loci varying between 2 and 5. The variance explained each locus ranged from 9.1% to 23.8% of the total. The variance explained by all loci responsible for each measurement ranged from 17.7% to 75.1%. It was noted that multiple measurements were mapped on the same locus. For example, a region bounded by Hym435 and Hym145 was found to be responsible for all the measurements analyzed.

Microporous Film, Made from β-Crystalline Phase Polypropylene

A new type microporous polypropylene film was prepared simply by biaxial drawing of β-crystalline phase polypropylene The effect of draw ratio on the pore size distribution, ethanol sorption, and porosity, as well as β-α transformation during drawing were studied For the purpose of improving its hydrophilicity ion and solute permeability, the plasma graft-polymerization technique was utilized The resulting film showed much higher permeability toward Na+, Mg++ and urea, being 3.2 × 10−6, 5.8 × 10−8 and 1.75 × 10−6 cm2/min, respectively, than the original one and had better dimensional stability.

p38 MAP kinase interacts with and stabilizes pancreatic and duodenal homeobox-1

Pancreatic and duodenal homeobox-1 (PDX-1) is a homeodomain-containing transcription factor that plays a critical role in pancreatic development, β-cell differentiation, maintenance of normal β-cell function and tumorigenesis. PDX-1 is subjected to extensive post-translational modifications for its stability, subcellular location and transactivity. We report here that PDX-1 expression is up-regulated by p38 MAP kinase. Antibody array screen identified p38 as a candidate PDX-1-interacting protein in GFP-PDX-1 stable HEK293 cells. The p38-PDX-1 interaction was confirmed by immunoprecipitation/Western blotting analysis in both transient transfection system of HEK293 cells and endogenous system of β-TC-6 cells stimulated by glucagon-like peptide 1 (GLP-1). Co-transfection of p38 with PDX-1 resulted in increased PDX-1 expression in HEK293 cells, which was accompanied by a decreased PDX-1 ubiquitination. Mass spectrometry analysis showed that Ser 268 of human PDX-1 was phosphorylated in GFP-PDX-1 stable HEK293 cells. Functional mutagenesis analysis showed that mutation of Ser 269 of mouse PDX-1 (corresponding to Ser 268 of human PDX-1) into nonphosphorylatable alanine abolished the stabilizing effect of p38 on PDX-1, which was in line with enhanced PDX-1 ubiquitination and shortened half-life of PDX-1. p38 showed kinase activity towards PDX-1 in vitro, suggesting that Ser 269 is a potential p38-regulated phosphorylation site within PDX-1. GLP-1-stimulated PDX-1 expression was accompanied by p38 kinase activation in mouse insulinoma β-TC-6 cells and p38 inhibitor SB202190 inhibited GLP-1-stimulated PDX-1 expression with accompanied inhibition of p38 kinase activation. Taken together, our studies indicated that p38 MAP kinase is a positive regulator of PDX-1 stability and that p38 exerts its stabilizing effect on PDX-1 through a phosphorylation-dependent inhibition of PDX-1 ubiquitination.

Levels of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 mRNAs in patients with primary hypertension or hypertension-induced atherosclerosis

OBJECTIVE

Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) affect degradation of vascular elastin, collagen remodelling and formation of atherosclerotic plaque. This cross-sectional study investigated the levels of MMP-9 and TIMP-1 mRNAs in the blood of patients with primary hypertension with and without hypertension-induced carotid atherosclerosis.

METHODS

Hypertensive patients with and without atherosclerosis and age- and gender-matched normotensive subjects were enrolled. MMP-9 and TIMP-1 mRNA were quantified using real-time reverse transcription-polymerase chain reaction.

RESULTS

Hypertensive patients (n = 86) had significantly lower levels of TIMP-1 mRNA than normotensive subjects (n = 43). Hypertensive patients with atherosclerosis (n = 42) showed significantly elevated levels of MMP-9 mRNA compared with both normotensive subjects and hypertensive patients without atherosclerosis (n = 44).

CONCLUSIONS

Primary hypertension resulted in decreased TIMP-1 mRNA levels, suggesting a potential mechanism contributing to the degradation of elastin. Hypertension-induced atherosclerosis was associated with significantly increased levels of MMP-9 mRNA, which may enhance both the deposition of types I and III collagen and atherosclerotic plaque formation.

Temperature-sensitive poly(N-isopropylacrylamide-co-butyl methylacrylate) nanogel as an embolic agent: distribution, durability of vascular occlusion, and inflammatory reactions in the renal artery of rabbits

BACKGROUND AND PURPOSE

We have developed a new thermosensitive liquid embolic agent, PIB nanogel, that can be solidified at body temperature. We thus further investigated the distribution, durability of vascular occlusion, and inflammatory reactions of PIB in embolization of the renal artery of rabbits.

MATERIALS AND METHODS

The bilateral renal arteries of 9 rabbits were first embolized with PIB at different injection rates. The distribution pattern of PIB was investigated by contact radiography and histology 1 hour after embolization. The right renal arteries of 20 rabbits were then embolized with PIB at the proper injection rate. Angiography and pathologic examination of the kidneys were performed at 1 week and 1, 2, and 3 months after embolization to evaluate the long-term outcomes.

RESULTS

With the injection rate increasing, PIB could reach the more distal branch of the renal artery. The proper injection rate was chosen as 0.10 mL/s due to the homogeneous distribution of PIB from the main renal artery to the precapillary level at this rate. During a 3-month follow-up observation period, no angiographic recanalization was observed. Histologically, we found no disruption of the vessel wall or subintimal bleeding, no extravasation of PIB, and no evidence of neovascularization. Moreover, there was only a mild inflammatory response, manifested by few lymphocytic and monocellular infiltration, without foreign body granuloma formation.

CONCLUSIONS

Embolization of the renal artery with PIB was easy and controllable, which could lead to a homogeneous and persistent occlusion without severe inflammatory changes. PIB might be a suitable material for intravascular embolization.

Development and comparison of a new personalized warfarin stable dose prediction algorithm in Chinese patients undergoing heart valve replacement

BACKGROUND

Pharmacogenetics-based algorithms would be especially desirable for patients undergoing heart valve replacement (HVR), who are particularly sensitive to warfarin during the initial treatment phase following surgery. We aimed to derive a warfarin dosing algorithm from data of Chinese patients undergoing HVR, and to compare it with previously published dosing algorithms as applied to our HVR patients.

METHODS

641 Chinese HVR patients on stable maintenance dose of warfarin were enrolled from a single clinic site. Data of 321 patients were used to derive a warfarin dosing algorithm using stepwise multiple linear regression analysis. Previously published algorithms were selected from Pubmed database for comparison. The performance of all the algorithms was characterized according to mean absolute error (MAE) and percentage of predicted doses falling within +/- 20% of clinically observed doses (percentage of ideal prediction) in the other 320 patients.

RESULTS

The newly developed algorithm included eight factors: VKORC1-1639G > A, CYP2C9*3, BSA, age, number of increasing INR drugs, smoking habit, preoperative stroke history and hypertension. Our algorithm accounted for 56.4% of variations in the inter-patient warfarin stable doses. All the algorithms showed better performance in a medium-dose (1.88-4.38 mg/day) and high-dose (> or = 4.38 mg/day) groupings than in a low-dose (< or = 1.88 mg/day) grouping. Compared with the 14 previously published algorithms, our algorithm had the lowest MAE (-0.07 mg/day) and the highest percentage of ideal prediction (62.8%) in the total validation cohort.

CONCLUSIONS

Our warfarin dosing algorithm is potentially useful for patients whose population profiles are similar to those of our patients.

P53 mutations may be related to tumor invasiveness of human hepatocellular-carcinoma in china

A combined polymerase chain reaction (PCR) with the enzyme HaeIII restriction analysis and DNA sequencing have been employed to study the mutations at codon 249 of p53 gene in two human hepatocellular carcinoma (HCC) cell lines and 28 surgical specimens of HCC. 14 of the 28 HCC samples (50%) had p53 point mutations at codon 249. All of point mutations at codon 249 in 10 cases sequenced are AGG to AGT transversion. p53 gene mutated more frequently in invasive HCCs than that in non-invasive HCCs. This suggested that the codon 249 was a mutational hotspot of p53 gene in human HCCs in China, and p53 mutations may be related to tumor invasiveness of human HCC.

Multilayered mucoadhesive hydrogel films based on thiolated hyaluronic acid and polyvinylalcohol for insulin delivery

A multilayered hydrogel film system based on hyaluronic acid-cysteamine (HA-Cym) and polyvinylalcohol (PVA) was fabricated. It contained a drug-impermeable backing layer, a supporting layer preventing direct contact between the loaded drug and the backing layer, a drug-loading layer and a mucoadhesive layer. Scanning electron microscopy demonstrated the presence of the distinct layers. The composition and preparation procedure of the films influenced their mucoadhesion, swelling, in vitro release of insulin and loaded insulin stability. Vacuum drying and crosslinked PVA with glutaraldehyde might reduce mucoadhesion, and they partially decreased the bioactivity of loaded insulin. Lyophilized hydrogel film with uncrosslinked PVA as a mucoadhesive layer possessed high mucoadhesion and showed no influence on the bioactivity of loaded insulin. The application of vacuum-dried PVA-crosslinked HA-Cym/PVA hydrogel film as a drug-impermeable backing layer would provide a controllable unidirectional insulin release. Therefore, such a multilayered hydrogel film system could be a promising mucoadhesive delivery system for controlled macromolecular drug release.