The case for allele‐specific recognition by the TCR

There is a sharp difference in how one views TCR structure–function–behaviour dependent on whether its recognition of major histocompatibility complex‐encoded restriction elements (R) is germline selected or somatically generated. The generally accepted or Standard model is built on the assumption that recognition of R is by the V regions of the αβ TCR, which is not driven by allele specificity, whereas the competing model posits that recognition of R is allele‐specific. The establishing of allele‐specific recognition of R by the TCR would rule out the Standard model and clear the road to a consideration of a competing construct, the Tritope model. Here, the case for allele‐specific recognition (germline selected) is detailed making it obvious that the Standard model is untenable.     

Redox active or thiol reactive? Optimization of rapid screens to identify less evident nuisance compounds

Compounds that exhibit assay interference or undesirable mechanisms of bioactivity are routinely encountered in assays at various stages of drug discovery. We observed that assays for the investigation of thiol-reactive and redox-active compounds have not been collected in a comprehensive review. Here, we review these assays and subject them to experimental optimization to improve their reliability. We demonstrate the usefulness of our assay cascade by assaying a library of bioactive compounds, chemical probes, and a set of approved drugs. These high-throughput assays should complement the array of wet-lab and in silico assays during the initial stages of hit discovery campaigns to pursue only hit compounds with tractable mechanisms of action.     

整合素α5β1在苯妥英钠促进大鼠PDLSCs和BMMSCs黏附于牙骨质中的作用

目的 探讨在苯妥英钠(Phenytoin,PHT)促进大鼠牙周膜干细胞(Rat periodontal ligament stem cells,rPDLSCs)、大鼠骨髓间充质干细胞(Rat Bone Marrow Mesenchymal Stem Cells,rBMMSCs)黏附于牙骨质过程中,整合素α5β1(Integrin α5β1)起到的作用。方法 提取大鼠BMMSCs和PDLSCs,培养并纯化。通过细胞鉴定后,将获得的两种细胞各分为4组:40 mg/L PHT处理组、40 mg/L PHT+整合素α5抗体处理组、40 mg/L PHT+整合素β1抗体处理组、PBS处理组,每组细胞放入置有牙骨质片的96孔板处理4 h后,检测黏附于牙骨质片上的细胞量并做以比较。最后,利用qRT-PCR和Western blot检测40 mg/L PHT组与对照组细胞的整合素α5、β1亚基的mRNA与蛋白表达量。结果 40 mg/L PHT可促进rBMMSCs及rPDLSCs黏附于牙骨质片,加入整合素α5、β1抗体后,均明显抑制了40 mg/L PHT对rBMMSCs、rPDLSCs黏附于牙骨质的促进作用(P＜0.01)。qRT-PCR、Western-blot结果显示PHT处理组的整合素α5、β1亚基表达量高于空白对照组(P＜0.05)。结论 40 mg/L PHT能促进rBMMSCs、rPDLSCs黏附于牙骨质,该作用与整合素α5β1的表达上调密切相关。     

Cost-effective differentiation of hepatocyte-like cells from human pluripotent stem cells using small molecules

Significant efforts have been invested into the differentiation of stem cells into functional hepatocyte-like cells that can be used for cell therapy, disease modeling and drug screening. Most of these efforts have been concentrated on the use of growth factors to recapitulate developmental signals under in vitro conditions. Using small molecules instead of growth factors would provide an attractive alternative since small molecules are cell-permeable and cheaper than growth factors. We have developed a protocol for the differentiation of human embryonic stem cells into hepatocyte-like cells using a predominantly small molecule–based approach (SM-Hep). This 3 step differentiation strategy involves the use of optimized concentrations of LY294002 and bromo-indirubin-3’-oxime (BIO) for the generation of definitive endoderm; sodium butyrate and dimethyl sulfoxide (DMSO) for the generation of hepatoblasts and SB431542 for differentiation into hepatocyte-like cells. Activin A is the only growth factor required in this protocol. Our results showed that SM-Hep were morphologically and functionally similar or better compared to the hepatocytes derived from the growth-factor induced differentiation (GF-Hep) in terms of expression of hepatic markers, urea and albumin production and cytochrome P450 (CYP1A2 and CYP3A4) activities. Cell viability assays following treatment with paradigm hepatotoxicants Acetaminophen, Chlorpromazine, Diclofenac, Digoxin, Quinidine and Troglitazone showed that their sensitivity to these drugs was similar to human primary hepatocytes (PHHs). Using SM-Hep would result in 67% and 81% cost reduction compared to GF-Hep and PHHs respectively. Therefore, SM-Hep can serve as a robust and cost effective replacement for PHHs for drug screening and development.     

羧甲基纤维素预防术后粘连的研究进展

目的 了解羧甲基纤维素（carboxymethylcellulose，CMC）预防术后粘连研究的进展。方法 广泛查阅近年来的相关文献，对CMC的理化特性、预防粘连的机制、吻合口愈合的影响以及在动物实验／临床上的应用效果进行综述。结果 CMC是一种组织相容性良好、可生物降解及理化特性稳定，能有效预防术后粘连的多糖类化合物。结论 CMC用于预防术后粘连具有较为广阔的前景。     

溃疡性结肠炎患者外周血中性粒细胞凋亡与粘附分子水平的关系及意义

目的　探讨溃疡性结肠炎 (U C)患者外周血中性粒细胞 (PMN)凋亡机制。方法　采用流式细胞术检测 32例 UC患者外周血 PMN凋亡 ,EL ISA法检测 P-选择素 (P- sel)和细胞间粘附分子 - 1(ICAM- 1)的水平。结果　活动期 UC患者 PMN凋亡率明显低于对照组和缓解期 UC患者 (P<0 .0 1)。不同病情活动期 U C患者 PMN凋亡有显著性差异 (P<0 .0 1)。活动期 UC患者外周血中 P- sel和 ICAM- 1水平均高于对照组和缓解期 U C患者(P<0 .0 1或 (P<0 .0 5 ) ,且与 PMN凋亡呈负相关 (r值分别为 - 0 .72 38和 - 0 .5 2 13,P均 <0 .0 1) ,与病情呈正相关。结论　各种免疫细胞粘附分子表达上调可能是导致 UC患者 PMN凋亡延迟的重要机制     

褪黑素对子宫内膜异位症大鼠细胞凋亡相关蛋白的影响

目的观察褪黑素(MT)对大鼠子宫内膜异位症(EM)模型细胞凋亡调控相关蛋白的影响。方法采用手术移植法制备大鼠EM模型,大鼠随机分为正常对照组、模型对照组和MT高、低剂量组,免疫组织化学法检测异位内膜Bcl-2、Fas、细胞间粘附分子(ICAM)-1的表达,同时检测脾脏自然杀伤(NK)细胞活性。结果MT治疗组与模型组比较异位内膜Bcl-2、ICAM-1表达明显下降,Fas表达明显升高,脾脏NK细胞活性显著增加。结论MT具有抑制异位内膜Bcl-2、ICAM-1表达以及增强Fas表达和脾脏NK细胞活性的作用。