The calpain system

The calpain system originally comprised three molecules: two Ca2+-dependent proteases, mu-calpain and m-calpain, and a third polypeptide, calpastatin, whose only known function is to inhibit the two calpains. Both mu- and m-calpain are heterodimers containing an identical 28-kDa subunit and an 80-kDa subunit that shares 55-65% sequence homology between the two proteases. The crystallographic structure of m-calpain reveals six "domains" in the 80-kDa subunit: 1). a 19-amino acid NH2-terminal sequence; 2). and 3). two domains that constitute the active site, IIa and IIb; 4). domain III; 5). an 18-amino acid extended sequence linking domain III to domain IV; and 6). domain IV, which resembles the penta EF-hand family of polypeptides. The single calpastatin gene can produce eight or more calpastatin polypeptides ranging from 17 to 85 kDa by use of different promoters and alternative splicing events. The physiological significance of these different calpastatins is unclear, although all bind to three different places on the calpain molecule; binding to at least two of the sites is Ca2+ dependent. Since 1989, cDNA cloning has identified 12 additional mRNAs in mammals that encode polypeptides homologous to domains IIa and IIb of the 80-kDa subunit of mu- and m-calpain, and calpain-like mRNAs have been identified in other organisms. The molecules encoded by these mRNAs have not been isolated, so little is known about their properties. How calpain activity is regulated in cells is still unclear, but the calpains ostensibly participate in a variety of cellular processes including remodeling of cytoskeletal/membrane attachments, different signal transduction pathways, and apoptosis. Deregulated calpain activity following loss of Ca2+ homeostasis results in tissue damage in response to events such as myocardial infarcts, stroke, and brain trauma.     

Emergency department visits for asthma: the role of frequent symptoms and delay in care.

BACKGROUND: Use of the emergency department (ED) for asthma care is a costly form of health care that is largely preventable. However, little is known about how to reduce the number of people using the ED for asthma care. OBJECTIVE: To identify modifiable factors related to ED visits for asthma among a diverse nonelderly adult population. METHODS: This study used cross-sectional data from the 2001 California Health Interview Survey. A total of 4,359 adult respondents ages 18 to 64 years who reported being diagnosed as having asthma and experiencing symptoms in the past year were included. Any ED visits due to asthma in the previous 12 months among all nonelderly respondents with asthma, with stratification by those with daily or weekly symptoms and with less frequent symptoms, were examined. RESULTS: Adults with daily or weekly asthma symptoms, with fair or poor health status, and who delayed care for asthma because of cost or insurance issues were more likely to visit the ED for asthma. Stratification of the study population into those with daily or weekly symptoms and those with less frequent symptoms revealed that delay in care due to cost or insurance issues and fair or poor health status remained significant for both groups. Latinos and women were more likely to visit the ED in the severe asthma group, whereas Asian, African American, and uninsured adults were more likely to visit the ED in the group with less severe asthma. CONCLUSIONS: Results suggest that to prevent ED visits for asthma, it is important to control asthma symptoms. However, it is equally if not more important to reduce delays in receiving asthma care.     

介绍一种制备特异性TF和特异性iRNA的方法

以乙肝疫苗、人喉癌细胞膜抗原为抗原，猪脾细胞为效应细胞，经体外免疫后收集应答细胞，制备ＰＳＨＢＶ－ＴＦ ＰＳＡＣ－ｉＲＮＡ。通过抗原特异性细胞免疫功能试验证实，ＰＳＨＢＶ－ＴＦ和ＰＳＡＣ－ｉＲＮＡ都能转移特异性细胞免疫功能。采用体外免疫法制备ＰＳＨＢＶ－ＴＦ和ＰＳＡＣ－ｉＲＮＡ是可行的，并且具有诸多优点。     

Alterations of plasma antioxidants and mitochondrial DNA mutation in hair follicles of smokers

The effects of long-term smoking on mitochondrial DNA (mtDNA) deletions in hair follicles were investigated in subjects with different antioxidant capacity. Twenty-two male smokers with a smoking index of greater than 5 pack-years and without any known systemic diseases were recruited for this study. Forty healthy nonsmoking males were included as controls. We found that the concentrations of ascorbate and alpha-tocopherol and the activities of glutathione S-transferase (GST) and glutathione peroxidase in blood plasma were significantly decreased in smokers. The levels of glutathione and protein thiols in whole blood and the incidence of a 4,977 bp deletion of mtDNA (dmtDNA) in hair follicles were significantly increased in smokers. A significantly higher incidence of the 4,977 bp dmtDNA was found in smokers with plasma GST activity less than 5.66 U/l (OR = 7.2, P = 0.020). Using multiple covariate ANOVA and logistic regression, we found that age and low plasma GST activity were the only two risk factors for the 4,977 bp dmtDNA. These results suggest that smoking depletes antioxidants and causes mtDNA deletions and that plasma GST may play an important role in the preservation of the mitochondrial genome in tissue cells of smokers.     

Multi-virulence-locus sequence typing clarifies epidemiology of recent listeriosis outbreaks in the United States

Multi-virulence-locus sequence typing (MVLST) was used to analyze isolates from two major listeriosis outbreaks in the United States in 1998 and 2002 that were due to consumption of contaminated hot dogs and turkey deli meat, respectively. MVLST demonstrated high epidemiological relevance and indicated that the two outbreaks were the result of one epidemic.     

3～20周人胚和胎儿肾小体的组织发生

应用光、电镜对3～20周22例人胚和胎儿肾小体的组织发生进行了观察.受精后第25天胚肾已有肾小体发生.随着胚龄的增长,肾小体的发生数目增多,肾小体的形成方式是:胚肾内先形成许多厚壁小管,在一部分厚壁小管的诱导下,另一部分厚壁小管的一侧壁呈帽状增厚,分化形成造血干细胞、毛细血管内皮及肾小囊脏层,对侧壁形成肾小囊壁层.即厚壁小管的双侧壁形成肾小体.     

Opa相互作用蛋白5在胰腺癌中的表达及其对PANC-1细胞增殖的影响

目的探索Opa相互作用蛋白5(OIP5)在胰腺癌中的表达及其对PANC-1细胞增殖的影响。方法通过数据库分析OIP5在胰腺癌组织及癌旁组织中的表达;用实时定量PCR(RT-qPCR)和蛋白印迹法(Western blot)分别检测人胰腺癌细胞系MIAPaCa-2、PANC-1、KP-3、BxPC-3细胞中OIP5 mRNA和蛋白表达;构建OIP5基因沉默质粒的慢病毒(pGCSIL-shOIP5)和对照质粒慢病毒(pGCSIL-shCtrl),分别感染PANC-1细胞,分为OIP5基因沉默组和shCtrl对照组,5 d后采用RT-qPCR和Western blot测定慢病毒敲低效率,流式细胞计量术检测细胞凋亡;OIP5基因沉默组和shCtrl对照组连续5 d进行MTT检测和细胞计数;OIP5基因沉默组和shCtrl对照组孵育10 d形成集落,Giemsa染色分别集落总数。结果胰腺癌中OIP5 mRNA表达显著高于正常胰腺组织(P<0.05),OIP5高表达患者的总存活率显著低于OIP5低表达患者(P<0.05),且其无病生存率也显著降低(P<0.05);OIP5在MIAPaCa-2、PANC-1和KP-3中表达较高,而在BxPC-3细胞系中的表达较低;MTT检测结果显示OIP5沉默在第4和第5天显著降低了PANC-1细胞的增殖速率(P<0.01);OIP5沉默后细胞集落数(平均为9个)显著低于shCtrl对照组中的数量(平均为40个)(P<0.01);OIP5沉默后PANC-1细胞凋亡比例为8.3%显著高于shCtrl的4.5%(P<0.01)。结论OIP5在胰腺癌细胞系中异常高表达,OIP5基因可调控胰腺癌PANC-1细胞的增殖、凋亡以及集落形成,提示OIP5可能在胰腺癌发病机制中作为癌基因发挥作用,从而为胰腺癌的靶向治疗提供了潜在的生物标志物。     

应用聚合酶链反应技术检测肝组织中的HBV－DNA

采用聚合酶链反应（ＰＣＲ）技术，对４２例肝活切组织石蜡切片中乙型肝炎病毒（ＨＢＶ）ＤＮＡ进行检测，并与乙肝表面抗原（ＨＢｓＡｇ）的免疫组织化学及血清学检测进行比较，ＨＢＶ－ＰＣＲ阳性率为７３．８％，高于组织及血清ＨＢｓＡｇ阳性率（分别为５９．５％和５０．０％）。３例病理形态呈肝炎改变，而血清ＨＢｓＡｇ（─）的肝组织中有２例检出ＨＢＶ－ＤＮＡ，提示ＰＣＲ的高度敏感性和准确性。８３．３％的门脉性肝硬变和８７．５％的肝细胞癌组织中ＨＢＶ－ＰＣＲ呈阳性，进一步证实了上述两病与ＨＢＶ的关系密切。我们还发现肝细胞淤胆患者ＨＢＶ感染率较高，ＨＢＶ－ＤＮＡ及组织ＨＢｓＡｇ阳性比例各为６／９和４／８。