Isolation and characterization of recombinant Escherichia coli clones secreting a 24-kilodalton antigen of Treponema pallidum.

Escherichia coli clones containing Treponema pallidum DNA in the pUC8 vector and secreting a 24-kilodalton antigen of T. pallidum have been isolated. Both syphilitic human and syphilis-immune rabbit sera reacted with the recombinant p24 antigen, indicating that an equivalent protein in T. pallidum is capable of eliciting antibody responses during natural infections. The p24 antigen of T. pallidum was identified by using two-dimensional gel electrophoresis and immunoblotting with monospecific anti-p24 serum. We tentatively concluded that this cloned antigen is a secreted protein or a labile or minor component of T. pallidum because (i) p24 was secreted by the recombinant E. coli cells; (ii) recombinant p24 in E. coli cells was processed into several smaller species with molecular masses ranging from 12 to 20 kilodaltons, which correlate well with the masses of secreted antigens described by others; and (iii) p24 protein appeared to be highly antigenic during natural infections, but only a very small amount of this antigen was associated with or retained by the purified organisms. The possible role of the p24 protein in determining the growth characteristics of T. pallidum is suggested by the ability of recombinant p24 to induce growth changes in E. coli cells. All E. coli colonies expressing the p24 polypeptide exhibited a flat and rough colony morphology and a filamentous growth pattern that were different from those of other E. coli cells. The DNA sequence coding for the p24 polypeptide is located on a 1.7-kilobase-pair BamHI fragment of the T. pallidum genomic DNA and is absent in the nonpathogenic Treponema phagedenis DNA. However, any possible relationship between the p24 antigen and the virulence of T. pallidum remains to be determined. In preliminary studies, rabbits immunized with the purified p24 were not protected from the infection with live T. pallidum organisms.     

工程化肌腱修复肌腱缺损后力学特性的组织学基础

探讨组织工程化肌腱修复肌腱缺损后体内愈合过程中力学特性的组织学基础。取罗曼鸡肌腱细胞 ,经体外培养、扩增 ,与可降解生物材料聚羟基乙酸筛网构建工程化肌腱 ;将其植入修复 2 0只罗曼鸡第二趾深屈肌腱0 .5～ 0 .8cm缺损。术后第 2、4、6、8周取材 ,对标本进行大体、组织学及生物力学测定。植入 2、4、6、8周 ,新生肌腱在大体形态、细胞及胶原纤维排列方式上与正常肌腱相似 ,但新生肌腱的胶原纤维束并未形成较多的沿肌腱长度方向的致密结构 (“塑形”) ,导致其最大张力增加缓慢 ,到 8周时为 15 .4 0± 10 .6 3N,仅达正常肌腱的 2 3 ;8周时最大张应变为 2 2 .4 9± 10 .2 1 ,比正常肌腱大 10。结果表明 ,单纯聚羟基乙酸作支架 ,材料降解过快 ,新生肌腱失去了正常的力学刺激 ,“塑形”能力差 ,其生物力学强度低。提示 ,保持新生肌腱形成过程中正常的力学刺激对新生肌腱的“塑形”可能是至关重要的。     

Involvement of ERK, p38 and NF-kappaB signal transduction in regulation of TLR2, TLR4 and TLR9 gene expression induced by lipopolysaccharide in mouse dendritic cells

Toll-like receptors (TLR) are sentinel receptors capable of recognizing pathogen-associated molecule patterns (PAMP) such as lipopolysaccharide (LPS) and CpG-containing oligonucleotides (CpG ODN). TLR2 and TLR4 are major receptors for Gram-positive and Gram-negative bacterial cell wall components, respectively. TLR9 is necessary for CpG signalling. LPS or CpG ODN can activate immature dendritic cells (DC) and induce DC maturation characterized by production of cytokines, up-regulation of co-stimulatory molecules, and increased ability to activate T cells. However, little is known regarding the regulation of TLR gene expression in mouse DC. In this study, we investigated the regulation of TLR2, TLR4 and TLR9 gene expression by LPS in murine immature DC. TLR2, TLR4 and TLR9 mRNA were up-regulated following LPS stimulation. The up-regulation of TLR9 expression coincided with significantly increased production of tumour necrosis factor-alpha induced by LPS plus CpG ODN. While inhibition of extracellular signal-related kinase and NF-kappaB activation suppressed the up-regulation of the expression of TLR2, TLR4 and TLR9 mRNA, inhibition of p38 kinase prevented the up-regulation of TLR2 and TLR4 mRNA expression but enhanced the up-regulation of TLR9 expression. These results demonstrated that TLR2, TLR4 and TLR9 gene expression was differently regulated by LPS in mouse immature DC. Up-regulation of TLR2, TLR4 and TLR9 expression by LPS might promote the overall responses of DC to bacteria and help to explain the synergy between LPS and other bacterial products in the induction of cytokine production.     

平行平板流动腔的合理设计和使用

高度远小于横向和纵向几何尺寸的平行平板流动腔，是当前用以体外研究细胞力学行为，特别是细胞粘附特性的主要工具之一。本文从目前常用的平行平板流动腔内流体定常流动时的切应力表达式出发，指出该切应力表达式仅适用于小雷诺数条件，由此确定平行平板流动腔几何尺寸的合理选择；通过对小孔入流和出流的平行平板流动腔流场的分析，指出该切应力表达式只在远离孔口边界一定距离，即达到均匀流动后成立。     

Urothelial carcinoma of the urinary bladder with a component of acinar/tubular type differentiation simulating prostatic adenocarcinoma

We report a case of an 83-year-old man with a high-grade carcinoma of the urinary bladder who underwent cystoprostatectomy. The invasive carcinoma showed mixed, morphologically distinct patterns consisting of conventional high-grade urothelial carcinoma, glandular differentiation resembling enteric type adenocarcinoma, and acinar/tubular type differentiation, morphologically similar to Gleason grade 3 prostatic adenocarcinoma. Immunohistochemical studies revealed the acinar/tubular component of the tumor to be negative for prostate-specific antigen and prostatic acid phosphatase, but positive for cytokeratin 7, cytokeratin 20, high molecular weight cytokeratin (34 beta E12), and thrombomodulin, consistent with origin from the bladder rather than the prostate. Although bladder carcinomas composed of mixed morphologic patterns are not uncommon, to our knowledge, the presence of acinar/tubular type features simulating prostatic adenocarcinoma in such tumors has not been described elsewhere.     

对Bem性别角色量表的考察与修订

目的：对在性别角色研究中使用得最为广泛的工具-Bem量表进行介绍，考察它在中国文化下的信、效度并进行修订。方法：选取两个城市三所大学中的340名本科生为被试。经过项目分析、因素分析等统计方法，对构成量表的条目进行删除和保留。结果：最后由14项男性化条目和12项女性化条目构成新的Bem量表简本。结论：修订后的Bem量表在信、效度上有了明显的提高，可以成为进一步研究的工具。     

NO及NO合成酶与感染性休克

感染性休克病理生理学过程十分复杂。NO在其中的作用既具有有害的一面，同时也存在有利的一面。受内毒素、细胞因子等诱导，iNOS表达上调并产生大量NO，引起循环衰竭、组织细胞损伤以及通过调节炎症介质基因表达扩大全身炎症反应。另一方面，eNOS所产生的NO对机体具有保护作用。然而，感染性休克时，eNOS蛋白质合成及其功能受到损害，反而成为血管内皮功能失常、诱发多器官功能障碍的重要原因。     

PPARγ在不同周龄apoE-/-小鼠主动脉斑块表达及与斑块成份的相互关系

目的:研究PPARγ基因表达与ApoE-/-小鼠主动脉斑块成份的相互关系。方法:以20和40周龄ApoE-/-小鼠(n=10/组)为研究对象,相同基因背景和周龄C57BL/6 J小鼠设为对照。采用RT-PCR和免疫印迹技术检测各组小鼠主动脉PPARγ基因和蛋白表达变化;Movat 5色套染法和油红O染色检测ApoE-/-小鼠主动脉斑块成份;免疫组织化学技术检测斑块内PPARγ、SM-actin、MOMA-2抗原表达。结合免疫荧光技术分析PPARγ基因在主动脉斑块巨噬细胞、平滑肌细胞的表达及与脂质、弹性纤维、胶原和蛋白聚糖的相互关系。结果:20和40周龄C57BL/6 J小鼠主动脉壁有少量PPARγ表达,以20周龄组明显。ApoE-/-小鼠主动脉壁和斑块内PPARγ表达增多,以斑块内表达明显(P<0.05);与20周龄组比较,40周龄组表达最显著;且斑块脂质含量丰富;弹性纤维、胶原和蛋白聚糖含量减少,血管正性重塑明显;MOMA-2表达增加,SM-actin表达降低(P<0.05)。PPARγ在斑块内巨噬细胞、血管中膜平滑肌细胞和斑块内平滑肌细胞都有表达,但以脂质含量丰富处PPARγ表达最明显。结论:PPARγ在C57BL/6 J小鼠动脉壁表达随增龄而减少;在ApoE-/-小鼠主动脉壁和斑块内PPARγ表达随AS病变进程而增加。推测ApoE-/-小鼠主动脉斑块PPARγ表达上调可能是机体一种代偿行为和自我保护机制。     

Evidence for a major gene underlying bone size variation in the Chinese

Osteoporosis is a major public health problem defined as a loss of bone strength, of which bone size is an important determinant. In the present study, familial correlation and segregation analyses for the spine and hip bone sizes were performed for the first time in a Chinese sample composed of 393 nuclear families with a total of 1,193 individuals. The results indicate a major gene of codominant inheritance for spine bone size; however, there is no evidence of a major gene influencing hip bone size. Significant familial residual effects are found for both traits, suggesting their polygenic inheritance. Heritability estimates (±SE) for spine and hip bone size were 0.62 (0.13) and 0.59 (0.12), respectively. Sex and age differences in genotype‐specific average bone size were observed. Compared with our previous study on bone mineral density (BMD) in the same population, this study suggests that genetic determination of bone size may be different from that of BMD, and thus studying bone size as one surrogate phenotype for osteoporotic fractures may be necessary. Am. J. Hum. Biol. 16:68–77, 2004. © 2003 Wiley‐Liss, Inc.     

Lysine methylation within the globular domain of histone H3 by Dot1 is important for telomeric silencing and Sir protein association

The amino-terminal histone tails are subject to covalent post-translational modifications such as acetylation, methylation, and phosphorylation. In the histone code hypothesis, these exposed and unstructured histone tails are accessible to a repertoire of regulatory factors that specifically recognize the various modified histones, thereby generating altered chromatin structures that mediate specific biological responses. Here, we report that lysine (Lys) 79 of histone H3, which resides in the globular domain, is methylated in eukaryotic organisms. In the yeast Saccharomyces cerevisiae, Lys 79 of histone H3 is methylated by Dot1, a protein shown previously to play a role in telomeric silencing. Mutations of Lys 79 of histone H3 and mutations that abolish the catalytic activity of Dot1 impair telomeric silencing, suggesting that Dot1 mediates telomeric silencing largely through methylation of Lys 79. This defect in telomeric silencing might reflect an interaction between Sir proteins and Lys 79, because dot1 and Lys 79 mutations weaken the interaction of Sir2 and Sir3 with the telomeric region in vivo. Our results indicate that histone modifications in the core globular domain have important biological functions.