MV-mimicking micelles loaded with PEG-serine-ACP nanoparticles to achieve biomimetic intra/extra fibrillar mineralization of collagen in vitro

Since their discovery, matrix vesicles (MVs) containing minerals have received considerable attention for their role in the mineralization of bone, dentin and calcified cartilage. Additionally, MVs' association with collagen fibrils, which serve as the scaffold for calcification in the organic matrix, has been repeatedly highlighted. The primary purpose of the present study was to establish a MVs–mimicking model (PEG-S-ACP/micelle) in vitro for studying the exact mechanism of MVs-mediated extra/intra fibrillar mineralization of collagen in vivo. In this study, high-concentration serine was used to stabilize the amorphous calcium phosphate (S-ACP), which was subsequently mixed with polyethylene glycol (PEG) to form PEG-S-ACP nanoparticles. The nanoparticles were loaded in the polysorbate 80 micelle through a micelle self-assembly process in an aqueous environment. This MVs–mimicking model is referred to as the PEG-S-ACP/micelle model. By adjusting the pH and surface tension of the PEG-S-ACP/micelle, two forms of minerals (crystalline mineral nodules and ACP nanoparticles) were released to achieve the extrafibrillar and intrafibrillar mineralization, respectively. This in vitro mineralization process reproduced the mineral nodules mediating in vivo extrafibrillar mineralization and provided key insights into a possible mechanism of biomineralization by which in vivo intrafibrillar mineralization could be induced by ACP nanoparticles released from MVs. Also, the PEG-S-ACP/micelle model provides a promising methodology to prepare mineralized collagen scaffolds for repairing bone defects in bone tissue engineering.     

Stratified or Multicentre Analysis with Extended Mantel–Haenszel Statistics

Since its introduction in 1959 the ability of the classical Mantel-Haenszel (M–H) procedure for combining the odds ratios of a set of I 2 × 2 tables has led to its use also in stratified or multicentre type clinical trials. A familiar application is the M–H logrank test in survival analysis. An extension of the M–H procedure covering the case of 2 × K contingency tables (MANTEL , 1963) with ordered levels retains the essential property of pooling the results of I homogeneous tables (i.e. in absence of qualitative interactions). The assignment of some score for the K columns of a table is essential for the use of the method (in comparing 2 treatments). Some possibilities of score assignment are discussed: for clinical outcome variables such as the degree of severity of a disease, pain and so on, the score is at hand in a natural way. A less well-known type of scoring consists in ranking the observations of a continuous variable, leading to cell sizes of 1 or 0. In this case, however, if equidistant ranking was used, the E–M–H procedure appears as an extension of Wilcoxon's rank sum test and represents a powerful non-parametric approach in stratified or multicentre type designs with non normally distributed outcome variables. The results of some Monte-Carlo simulations for 2 possible equidistant ranking procedures are presented, which indicate only a moderate gain in power as compared to Wilcoxon's rank sum test under the common situation of centre effects not exceeding treatment effects. Use of the E–M–H pro?edure is also recommended as a simple method to overcome the potential bias due to unequally distributed prognostic factors among treatment groups.     

Differential susceptibility to hydrogen sulfide-induced apoptosis between PHLDA1-overexpressing oral cancer cell lines and oral keratinocytes: Role of PHLDA1 as an apoptosis suppressor

Hydrogen sulfide (H₂S) is a novel gasotransmitter that plays multiple biological roles in various body systems. In addition to its endogenous production, H₂S is produced by bacteria colonizing digestive organs, including the oral cavity. H₂S was previously shown to enhance pro-apoptotic effects in cancer cell lines, although the mechanisms involved remain unclear. To properly assess the anti-cancer effects of H₂S, however, investigations of apoptotic effects in normal cells are also necessary. The aims of this study were (1) to compare the susceptibility to H₂S-induced apoptosis between the oral cancer cell line Ca9-22 and oral keratinocytes that were derived from healthy gingiva, and (2) to identify candidate genes involved in the induction of apoptosis by H₂S. The susceptibility to H₂S-induced apoptosis in Ca9-22 cells was significantly higher than that in keratinocytes. H₂S exposure in Ca9-22 cells, but not keratinocytes, enhanced the expression of pleckstrin homology-like domain, family A, member 1 (PHLDA1), which was identified through a differential display method. In addition, PHLDA1 expression increased during actinomycin D-induced apoptosis in Ca9-22 cells. Knockdown of PHLDA1 expression by small interfering RNA in Ca9-22 cells led to expression of active caspase 3, thus indicating apoptosis induction. The tongue cancer cell line SCC-25, which expresses PHLDA1 at a high level, showed similar effects. Our data indicate that H₂S is an anti-cancer compound that may contribute to the low incidence of oral cancer. Furthermore, we demonstrated the role of PHLDA1 as an apoptosis suppressor.     

Honokiol: A non-adipogenic PPARγ agonist from nature

Background

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists are clinically used to counteract hyperglycemia. However, so far experienced unwanted side effects, such as weight gain, promote the search for new PPARγ activators.

Methods

We used a combination of in silico, in vitro, cell-based and in vivo models to identify and validate natural products as promising leads for partial novel PPARγ agonists.

Results

The natural product honokiol from the traditional Chinese herbal drug Magnolia bark was in silico predicted to bind into the PPARγ ligand binding pocket as dimer. Honokiol indeed directly bound to purified PPARγ ligand-binding domain (LBD) and acted as partial agonist in a PPARγ-mediated luciferase reporter assay. Honokiol was then directly compared to the clinically used full agonist pioglitazone with regard to stimulation of glucose uptake in adipocytes as well as adipogenic differentiation in 3T3-L1 pre-adipocytes and mouse embryonic fibroblasts. While honokiol stimulated basal glucose uptake to a similar extent as pioglitazone, it did not induce adipogenesis in contrast to pioglitazone. In diabetic KKAy mice oral application of honokiol prevented hyperglycemia and suppressed weight gain.

Conclusion

We identified honokiol as a partial non-adipogenic PPARγ agonist in vitro which prevented hyperglycemia and weight gain in vivo.

General significance

This observed activity profile suggests honokiol as promising new pharmaceutical lead or dietary supplement to combat metabolic disease, and provides a molecular explanation for the use of Magnolia in traditional medicine.     

Ultrasonication of insulin-loaded microgel particles produced by internal gelation: Impact on particle's size and insulin bioactivity

Alginate-dextran sulfate (ADS) microgel has been used to protect insulin from gastrointestinal attack and as a carrier to promote insulin permeation through intestinal epithelium. The throughput of ADS submicron particles generation by emulsification/internal gelation is limited by its wide size distribution.     

Multi-drug resistance-1 gene polymorphisms in nephrotic syndrome: Impact on susceptibility and response to steroids

Background

Role of multidrug resistance-1 (MDR-1) gene polymorphisms has not been clarified in nephrotic syndrome (NS). Additionally, researchers studied several genetic polymorphisms to explain their influence on different patients' responses to steroid; however the data were inconsistent. Therefore, we aimed to investigate the association of MDR-1 gene polymorphisms [C1236T, G2677T/A, C3435T] and haplotypes with susceptibility to childhood nephrotic syndrome, and whether they influence steroid response.

Methods

We detected MDR-1 gene polymorphisms using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 138 NS patients and 140 age and sex matched healthy children.

Results

The frequencies of MDR1 G2677T/A GT, GA, TT + AA genotypes or T allele, MDR1 C3435T TT genotype, and T allele genotype frequencies were significantly increased in NS group. While no significant differences were observed in distributions of C1236T genotypes or allele between NS patients and healthy children. Moreover, steroid non-responder NS patients had significantly higher frequencies of MDR1 G2677T/A GT, GA, and TT + AA genotypes than steroid responsive NS patients. We observed also that NS patients with age less than 6 years old had increased frequencies of MDR1 G2677T/A GT, GA, TT + AA genotypes or T allele MDR1 C3435T CT, TT genotypes and T allele. Interestingly the frequency of the TGC haplotype of MDR1 was lower in the initial steroid responders than in non-responders NS patients. On the contrary, there were no any association between the MDR1 haplotypes with NS susceptibility and they did not influence renal pathological findings.

Conclusion

Our data suggested that MDR1 C3435T or G2677T/A gene polymorphisms are risk factors of increased susceptibility, earlier onset of NS, and steroid resistance.     

GSTM1, GSTT1, GSTP1, and GSTA1 genetic variants are not associated with coronary artery disease in Taiwan

Background and objective

The genetic variants of xenobiotic-metabolizing enzymes, such as those encoded by glutathione-S-transferase (GST) genes, may be associated with the risk of coronary artery disease (CAD). To investigate the genetic factors for CAD, we examined the GSTM1, GSTT1, GSTP1, and GSTA1 genotypes in a CAD cohort in Taiwan.

Methods

Our study included 458 CAD participants and 209 control participants who received coronary angiography to assess CAD. The severity of CAD was defined as the number of coronary vessels with 50% or greater stenosis. Sequence variation of the GSTM1 and GSTT1 genes was determined using a polymerase chain reaction (PCR). The GSTP1 (Ile105Val), and GSTA1 (-69C > T) genetic variants were identified using a combination of PCR and restriction fragment length polymorphism analysis. Logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals.

Results

Among the GST genetic variants examined, the GSTT1 null genotype was more prevalent in CAD participants with 3 stenosed vessels than in control participants (OR = 1.64, P = .02). This association was no longer observed after adjusting for age, sex, smoking, alcohol use, diabetes mellitus, and serum levels of total cholesterol and high-density lipoprotein cholesterol (OR = 1.28, P = .40). Both univariate and multivariate logistic regression analyses found no significant associations between CAD and the other genetic variants, either separately or in combination. In addition, no effects of interactions between the genotypes and environmental factors, such as cigarette smoking, were significantly associated with the risk of CAD.

Conclusion

The GST genetic variants examined were not associated with susceptibility to CAD in our Taiwanese cohort. This null association requires further confirmation with larger samples.     

Associations of the PTEN − 9C>G polymorphism with insulin sensitivity and central obesity in Chinese

Background

Phosphatase and tensin homolog on chromosome 10 gene (PTEN) is known as a tumor-suppressor gene. Previous studies demonstrated that PTEN dysfunction affects the function of insulin. However, investigations of PTEN single nucleotide polymorphisms (SNPs) and IR-related disease associations are limited. The aim of the present study was to investigate whether its polymorphism could be involved in the risk of metabolic syndrome (MetS).

Methods

The genotype frequency of PTEN − 9C>G polymorphism was determined by using a Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) method in 530 subjects with MetS and 202 healthy control subjects of the Han Ethnic Chinese population in a case–control analysis.

Results

The PTEN − 9C>G polymorphism was not associated with MetS or its hyperglycemia, hypertension and hypertriglyceridemia components. In the control individuals aged < 60 years or ≥ 60 years, the CG genotype individuals had lower insulin sensitivity than CC individuals (P < 0.05). In the < 60-year-old MetS group and normal glucose tolerance (NGT) subgroup, the CG individuals had lower insulin sensitivity and higher waist circumference (WC) and waist-height-ratio (WHtR) than CC individuals (P < 0.05). Multiple linear regression analysis showed that the PTEN polymorphism (P = 0.001) contributed independently to 4.2% (adjusted R²) of insulin sensitivity variance (estimated by Matsuda ISI), while age (P = 0.004), gender (P = 0.000) and the PTEN polymorphism (P = 0.032) contributed independently to 5.6% (adjusted R²) of WHtR variance.

Conclusions

The CG genotype of PTEN − 9C>G polymorphism was not associated with MetS and some of its components as well. However, it may not only decrease insulin sensitivity in the healthy control and MetS in pre-elderly or NGT subjects, but may also increase the risk of central obesity among these MetS individuals.     

基于光谱特征变量的湿地典型植物生态类型识别方法——以北京野鸭湖湿地为例

光谱特征变量的选择对于湿地植被识别的精度和效率有着直接的影响作用.以华北地区典型的淡水湿地——野鸭湖湿地为研究区,采用Field Spec 3野外高光谱辐射仪,获取了野鸭湖典型湿地植物的冠层光谱.以野外高光谱数据为基础,首先利用一阶导数与包络线去除的方法,分析和对比不同植物生态类型的光谱特征,选定了用于识别植物生态类型的光谱特征变量,选定的8个光谱特征变量为红边位置WP_r、红边幅值Dr、绿峰位置WP_g、绿峰幅值Rg、510 nm附近的吸收深度DEP-510和吸收面积AREA-510、675 nm附近的吸收深度DEP-675和吸收面积AREA-675.其中,7种植物生态类型的一阶导数光谱特征差异较小,吸收特征差异性相对较大.除WP_r和WP _g外,沉水植物Rg和Dr平均值最低,湿生植物的Rg平均值最高,达到0.164,栽培植物的Dr平均值最高,达到0.012.7种植物生态类型在675 nm附近的DEP-675和AREA-675均高于510 nm附近的DEP-510与AREA-510,除去栽培植物,随着水分梯度的变化,其他6种植物生态类型的吸收深度和吸收面积都表现出先升高后降低的趋势.然后利用单因素方差分析(One-way ANOVA)验证了所选光谱特征变量的区分度,在P≤0.01的置信水平下,选取的8个光谱特征变量都能够较好的区分7种植物生态类型,区分度的最小值为13,最大值为18,并且吸收特征参数的区分度优于一阶导数参数.最后应用非线性的反向传播人工神经网络(BP-ANN)与线性判别分析(FLDA)的类型识别方法,利用选定的8个光谱特征变量进行湿地植物生态类型识别,取得了较好的识别精度,两种方法的总分类精度分别达到85.5％和87.98％.单因素方差分析(One-way ANOVA)和不同分类器的分类精度表明,所选的8个光谱特征变量具有一定的普适性和可靠性.     

Microhabitat Variation Explains Local‐scale Distribution of Terrestrial Amazonian Lizards in Rondônia,Western Brazil

We investigate the role of ecology and phylogeny in the association between lizard abundance and microhabitat variables in an Amazon rain forest site. Using pitfall trap arrays, we collected data from 349 individuals belonging to 23 lizard species. After accounting for spatial autocorrelation and using a canonical correspondence analysis (CCA), we found that lizard captures were significantly associated with microhabitat variables, which accounted for 48 percent of the observed variation. Furthermore, a canonical phylogenetic ordination (CPO) indicated that microhabitat variables are more important in determining the distribution of lizard species than phylogenetic relationships among species. Termite nests, canopy openness, and tree circumference were strongly associated with the number of captures of certain lizard species. Our results confirm autecology studies of individual lizard species for which data are available. We suggest that maintaining heterogeneous forested microhabitats should be a central goal for sustaining a high lizard biodiversity in Amazon rain forests.