环孢菌素A阻断人HL－60抗药性细胞于G_1期而诱导敏感细胞凋亡

进一步研究了抗三尖杉酯碱的ＨＬ－６０细胞（ＨＲ２０）抗细胞凋亡的机制及该抗性和抗药性的关系。结果表明，环孢菌素Ａ（ＣｓＡ）２０，１０μｇ·ｍｌ￣（－１）诱导ＨＬ－６０细胞发生凋亡，而阻断ＨＲ２０细胞于Ｇ＿１期，就不能诱导细胞发生凋亡。低浓度的ＣｓＡ明显增加柔红霉素在ＨＲ２０细胞内的积聚，其逆转抗药性作用与阻断细胞周期运行无关。ＣｓＡ１０μｇ·ｍｌ￣（－１）处理ＨＲ２０细胞，可引起５０ｋＤａ的蛋白质高度磷酸化。结果提示：环孢菌素Ａ阻断抗三尖杉酯碱的ＨＬ－６０细胞于Ｇ＿１期，而诱导敏感的ＨＬ－６０细胞发生凋亡，其阻断作用与抗药性无关     

Immunoglobulin production in vitro by peripheral blood lymphocytes in systemic lupus erythematosus: helper T cell defect and B cell hyperreactivity

Peripheral blood lymphocytes (PBL) from 16 patients with systemic lupus erythematosus (SLE) and 15 healthy control subjects were cultured and immunoglobulin (Ig) production in vitro was measured by immunofluorescent staining for intracytoplasmic Ig, a reverse haemolytic plaque assay to quantify cells secreting Ig and a solid-phase radioimmunoassay for Ig secreted into culture supernatants. Compared with normal PBL, lymphocytes from patients with SLE produced significantly fewer Ig-containing cells, Ig-secretion cells (ISC) and less Ig in supernatants in cultures stimulated by pokeweed mitogen (PWM). These differences were most pronounced during phases of disease activity. Culturing SLE PBL with a supernatant obtained from PWM-activated cultures of normal T lymphocytes partially restored their capacity to produce ISC. This observation suggests a helper T cell defect of SLE lymphocytes. In addition, PBL from patients with active SLE generated more ISC when cultured with Staphylococcus aureus bacteria (S aureus) than with PWM. S. aureus-stimulated cultures of SLE PBL also generated more ISC than PBL from normal individuals. The S. aureus response of SLE lymphocytes did not correlate with disease activity. As S. aureus is a T cell-independent mitogen, the latter observations suggest that in SLE an intrinsic B cell hyperreactivity may be a more persistent defect whereas T cell defects are transitory.     

Association between genetic variants in sortilin-related receptor 1 (SORL1) and Alzheimer's disease in adults with Down syndrome

Recent reports have suggested that variants in the sortilin-related receptor gene (SORL1) increase the risk of late onset Alzheimer's disease (AD) in Northern European, Hispanic, African–American and Isreali–Arab populations. SORL1 directs trafficking of amyloid precursor protein (APP) and under-expression of SORL1 may lead to over-expression of β amyloid peptides. Adults with Down syndrome (DS) over-express APP and have early onset and high risk for AD. We investigated the relation of seven variants in the gene for SORL1 to age at onset and risk for AD among 208 adults with DS, 45–70 years of age at baseline. Participants were ascertained through the New York State developmental disability service system and followed at 18-month intervals. Information from cognitive assessments, caregiver interviews, medical record review and neurological examination was used to establish the diagnosis of dementia. Homozygosity for the minor T allele in rs556349 and for the minor C allele in rs536360 was associated with later age at onset and reduced risk of AD (HR = 0.26, 95% CI: 0.08–0.86; and HR = 0.40, 95% CI: 0.16–0.98, respectively). Mean age at onset was approximately four years later in individuals who were homozygous for those alleles compared with those who had at least one major allele. These findings indicate a modest association of variants in SORL1 with AD. In addition, we did not observe the same alleles to be associated with AD compared with earlier studies, suggesting that these SNPs are in linkage disequilibrium (LD) with the putative functional variants or that expression of the SORL1 gene and hence its interaction with APP might be modified by the extremely high levels of APP characteristic of Down syndrome. Thus, further studies are needed to identify functional variants that influence risk for AD in this uniquely vulnerable population.     

Nanopattern-induced changes in morphology and motility of smooth muscle cells

Cells are known to be surrounded by nanoscale topography in their natural extracellular environment. The cell behavior, including morphology, proliferation, and motility of bovine pulmonary artery smooth muscle cells (SMC) were studied on poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) surfaces comprising nanopatterned gratings with 350 nm linewidth, 700 nm pitch, and 350 nm depth. More than 90% of the cells aligned to the gratings, and were significantly elongated compared to the SMC cultured on non-patterned surfaces. The nuclei were also elongated and aligned. Proliferation of the cells was significantly reduced on the nanopatterned surfaces. The polarization of microtubule organizing centers (MTOC), which are associated with cell migration, of SMC cultured on nanopatterned surfaces showed a preference towards the axis of cell alignment in an in vitro wound healing assay. In contrast, the MTOC of SMC on non-patterned surfaces preferentially polarized towards the wound edge. It is proposed that this nanoimprinting technology will provide a valuable platform for studies in cell-substrate interactions and for development of medical devices with nanoscale features.     

大鼠胸腺降黑素受体的鉴定及生物学特性

应用放射配体结合法证实大鼠胸腺内存在降黑素特异结合部位，该结合位点可以满足特异结合部位的基本条件：１．低结合容量；２．高亲和力；３．可饱和性；４．可逆性；５．对降黑素高度特异性。此外，该特异结合位点具昼夜节律；亚细胞分布的研究表明以细胞核含量最高，线粒体次之，并具有年龄依赖性降低，以出生时最高。     

Induction and characterization of heat shock proteins of Salmonella typhi and their reactivity with sera from patients with typhoid fever.

The heat shock protein (HSP) response of Salmonella typhi following exposure to elevated growth temperatures was studied. Three major proteins with molecular sizes of 58, 68, and 88 kDa were abundantly expressed when S. typhi cells were shifted from 37 to 45 degrees C and to 55 degrees C. These proteins were also constitutively expressed at 37 degrees C. Western blotting and immunoprecipitation studies with anti-HSP monoclonal antibodies revealed that the 58- and 68-kDa proteins were analogous to the GroEL and DnaK proteins, respectively, of Escherichia coli. These HSPs are also abundantly present in the outer membrane fraction of disrupted cells and, to a lesser extent, in the cytosol. Immunoblotting experiments with sera from patients with a culture-positive diagnosis of typhoid fever showed the presence of antibodies to these HSPs. Nine of twelve sera reacted with the 58-, 68-, and 88-kDa proteins, while three sera reacted only with the 68- and 88-kDa proteins. All 10 sera from healthy individuals showed no binding to these HSPs. In light of the well-documented roles of HSPs in the pathogenesis of microbial infections and as immunodominant antigens, these findings may be relevant for a better understanding of disease processes and for the future development of diagnostic and preventive strategies.     

Epidemiologic analysis of sporadic Salmonella typhi isolates and those from outbreaks by pulsed-field gel electrophoresis.

Pulsed-field gel electrophoresis (PFGE) was used to compare and analyze 158 isolates of Salmonella typhi from five well-defined outbreaks of typhoid fever in Malaysia and also isolates involved in sporadic cases of typhoid fever occurring during the same period. Digestion of chromosomal DNAs from these S. typhi isolates with the restriction endonucleases XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3') and then PFGE produced restriction endonuclease analysis (REA) patterns consisting of 11 to 24 DNA fragments ranging in size from 20 to 630 kbp. Analysis of the REA patterns generated by PFGE after digestion with XbaI and SpeI indicated that the S. typhi isolates obtained from sporadic cases of infection were much more heterogeneous (at least 13 different REA patterns were detected; Dice coefficient, between 0.73 and 1.0) than those obtained during outbreaks of typhoid fever. The clonal nature and the close genetic identities of isolates from outbreaks in Alor Setar, Penang, Kota Kinabalu, Johor Bahru, and Kota Bahru were suggested by the fact that only a limited number of REA patterns, which mostly differed by only a single band, were detected (one to four patterns; Dice coefficient, between 0.82 and 1.0), although a different pattern was associated with each of these outbreaks. Comparison of REA patterns with ribotyping for 18 S. typhi isolates involved in sporadic cases of infection showed a good correlation, in that 72% of the isolates were in the same group. There was no clear correlation of phage types with a specific REA pattern. We conclude that PFGE of s. typhi chromosomal DNA digested with infrequently cutting restriction endonucleases is a useful method for comparing and differentiating S. typhi isolates for epidemiological purposes.     

16例应激性溃疡的临床诊治体会

目的 报告应激性溃疡的临床诊治体会。方法 全组16例,男12例,女4例。术前均无溃疡病史,血红蛋白检查均正常。术后早期应用糖皮质激素9例,出血前发生肺不张、严重呼吸道感染、呼吸功能不全6例,低血容量休克5例,急性重症出血坏死性胰腺炎4例,食管癌、贲门癌术后6例,严重烧伤(80％(?)Ⅱ°)1例。14例保守治疗,2例保守治疗无效而手术治疗。结果14例经治疗后(2例手术治疗)痊愈出院,2例死亡。结论 应激性溃疡大出血患者多病情危重,难以忍受二次手术,死亡率约为50％,因此应采取有效的保守治疗,对于保守治疗无效、大出血休克或胃肠穿孔者应及时手术治疗。     

Comparison of LightCycler-based PCR,COBAS amplicor CMV monitor,and pp65 antigenemia assays for quantitative measurement of cytomegalovirus viral load in peripheral blood specimens from patients after solid organ transplantation

In order to evaluate the LightCycler-based PCR (LC-PCR) as a diagnostic assay technique, a classical pp65 antigenemia assay and the commercially available COBAS Amplicor CMV Monitor (CACM) assay were compared to the LC-PCR assay for the detection and quantitation of cytomegalovirus (CMV) load in 404 parallel specimens of peripheral blood from 66 patients after solid organ transplantation. A good correlation existed among these three assays (r congruent with 0.6, P < 0.0001). The LC-PCR assay was the most sensitive (54% of specimens positive) compared to the CACM (48.6%) and the pp65 antigenemia (26%) assays. The LC-PCR assay detected all samples found positive by using both the CMV pp65 antigenemia assay and the CACM assay. The LC-PCR also had the widest dynamic range (from 250 to 10(7) DNA copies/ml of plasma). No cross-reactions were found among CMV and Epstein-Barr virus, varicella-zoster virus, or herpes simplex virus in the LC-PCR by using amplification with specifically designed primer pairs. Precision, expressed as the coefficient of variation, was <3% with standard DNA from cell cultures and between 6.55 and 14.1% with clinical specimens in repeat LC-PCR runs. One run of the LC-PCR took half of the time required for the semiautomated CACM procedure. Because of its sensitivity, specificity, cost-effectiveness, and simplicity, the LC-PCR assay could replace the pp65 antigenemia and the CACM assays as the preferred technique for the surveillance, diagnosis, and monitoring of response of CMV diseases in high-risk populations.