The role of white cells in the transmission of Yersinia enterocolitica in blood components

The mechanism for the transmission of Yersinia enterocolitica in blood components has been studied experimentally. One hypothesis is that, during a Yersinia infection in the blood donor, bacteria are phagocytosed by white cells (WBCs), but are not killed. After collection of blood from such a donor and component production, the bacteria are present in WBCs for some time, during which the unit appears sterile. Later, when the WBCs disintegrate, the bacteria are released and multiply in the unit. Aliquots of whole blood and buffy coat were inoculated with 100 colony-forming units (CFU) per mL of a Y. enterocolitica strain of type O:3 and left at room temperature for 5 hours. Some aliquots were then WBC-reduced by filtration, while others retained their WBC contents. All aliquots were kept at 4 degrees C for 6 weeks. Meat extract broth culture medium was used as a control. Growth in the range of 2000 CFU per mL was obtained in the broth control by 24 hours, whereas the whole blood and buffy coat units appeared sterile for the first days of storage. After 1 week, a trace of bacteria and, after 4 weeks, massive growth were found in the WBC-containing units but not in the WBC-reduced units. The likely explanation is that the bacteria had been phagocytosed by the WBCs and were thereby hidden and not available for bacterial culture during the first phase of storage. When the WBCs spontaneously disintegrated, bacteria were released and multiplied in the blood units.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phosphoenolpyruvate in the rejuvenation of stored red cells in SAGM medium: optimal conditions and the indirect effect of methemoglobin formation

Red cells stored in saline-adenine-glucose-mannitol (SAGM) medium were rejuvenated by incubation with phosphoenolpyruvate (PEP) under conditions that can be achieved easily in ordinary blood banking. Regeneration of 2,3 diphosphoglycerate (2,3 DPG) and adenine nucleotides of stored red cells was dependent on the pH of the incubation medium and the incubation time. In red cells stored for 3 and 5 weeks, the optimal pH and incubation time for regeneration of 2,3 DPG and adenine nucleotides were 5.8 and 90 minutes and 6.1 and 60 minutes, respectively. During the incubation of red cells with PEP, methemoglobin was formed; it increased when the medium pH was below 6.0 and the incubation time exceeded 60 minutes. We conclude that incubation at a medium pH of 6.1 for 60 minutes is optimal for the rejuvenation of stored red cells with PEP. Under such incubation conditions, the concentrations of 2,3 DPG and adenine nucleotides in red cells stored for 5 weeks were restored to normal without methemoglobin formation.     

Clinical usefulness of cystatin C for the estimation of glomerular filtration rate in type 1 diabetes: reproducibility and accuracy compared with standard measures and iohexol clearance

OBJECTIVE-Assessment and follow-up of early renal dysfunction is important in diabetic nephropathy. Plasma creatinine is insensitive for a glomerular filtration rate (GFR) >50 ml/min and creatinine clearance is unwieldy and subject to collection inaccuracies. We aimed to assess the reproducibility, reliability, and accuracy of plasma cystatin C as a measure of GFR ranging from normal to moderate impairment due to type 1 diabetes in the presence of a normal plasma creatinine concentration. RESEARCH DESIGN AND METHODS-A sensitive immunoturbidimetric cystatin C assay was examined in 29 subjects with type 1 diabetes and 11 nondiabetic subjects. Duplicate measurements of the following were collected from each subject, 2 weeks apart: cystatin C, enzymatic plasma creatinine, 24-h creatinine clearance, GFR estimated from plasma creatinine by the Cockcroft-Gault equation, and iohexol clearance as a gold standard. RESULTS-Iohexol clearance ranged from 35 to 132 ml. min(-1). 1.73 m(-2). Plasma cystatin C compared well with the other clinically used tests. The reliability of cystatin C, as assessed by the discriminant ratio, was superior to creatinine clearance (3.4 vs. 1.5, P < 0.001) and the correlation of cystatin C with iohexol clearance (Rs -0.80) was similar to that of creatinine clearance (Rs -0.74) and superior to that of plasma creatinine and the Cockcroft-Gault estimate (Rs -0.54 and 0.66, respectively). Duplicate estimations were used to provide an unbiased equation to convert plasma cystatin C to GFR. CONCLUSIONS-Based on this study, cystatin C is a more reliable measure of GFR than creatinine clearance, is more highly correlated with iohexol clearance than plasma creatinine, and is worthy of further investigation as a clinical measure of GFR in type 1 diabetes.     

有氧运动延缓衰老线粒体DNA突变的机制

目的:线粒体DNA突变在衰老过程中起核心作用。总结有氧运动在延缓机体衰老过程中对线粒体DNA突变的影响,探讨有氧运动延缓衰老的机制。资料来源:应用计算机检索Medline数据库1996-01/2006-01期间关于线粒体DNA突变与有氧运动延缓衰老的文章,检索词为"aerobics exercise,aging,mtDNA mutation",限定文章语言种类为English。同时计算机检索中国期刊全文数据库、万方数据库1994-01/2006-12期间的有氧运动、衰老和线粒体DNA突变相关的文章,检索词"衰老,线粒体DNA突变,有氧运动",并限定文章语言种类为中文。资料选择:对资料进行初审,纳入标准:①有氧运动延缓衰老关系的理论研究。②线粒体DNA突变与衰老关系的基础与临床研究。③有氧运动对线粒体DNA突变的影响研究。资料提炼:共收集到36篇线粒体DNA突变与有氧运动延缓衰老相关的文献,均为全文,32篇符合纳入标准,排除4篇重复性研究。资料综合:①有氧运动可以通过减少线粒体DNA突变,从而达到延缓机体的衰老。有氧运动可能通过影响自由基及抗氧化系统、细胞凋亡、线粒体的结构和功能,对衰老进程产生重要影响。②线粒体DNA突变随增龄而积累,达到一定阈值后,可导致细胞能量供应的严重障碍,从而造成组织器官生理功能的减退。③长期有氧运动可通过刺激心肌、骨骼肌线粒体的生成及蛋白质的合成而延缓线粒体形态结构的改变,有利于维持线粒体功能以满足机体对其能源的需求。结论:中、低强度有氧运动可以提高机体有氧工作能力,增进线粒体氧化磷酸化的功能,对延缓衰老具有一定的积极作用。有氧运动可以减少心肌、骨骼肌等线粒体DNA突变,提示有氧运动在延缓衰老机制中,减少线粒体DNA突变是可能机制之一。     

大鼠眼外肌成肌细胞的增殖及分化特征

目的:完善眼外肌成肌细胞体外培养、鉴定的方法及观察其生物学特性。方法:实验于2005-02/08在青岛大学医学院附院中心实验室(省级实验室)完成。取出生后3～7d的大鼠,通过大鼠眼外肌细胞的取材、分离、消化、培养等技术,观察细胞的形态、生长曲线、细胞融合率,观察大鼠眼外肌卫星细胞的增殖与分化能力,利用成肌细胞标记物α-横纹肌肌动蛋白、中间丝结蛋白免疫细胞化学染色对所获得的细胞进行鉴定。结果:①成肌细胞的生长情况:在生长培养基作用下,细胞增殖旺盛;在分化培养基条件下,细胞分化良好,可融合成肌管。②成肌细胞融合率:在24h和48h融合率提高明显,72h达高峰,之后不再变化。③细胞免疫化学检测结果:α-横纹肌肌动蛋白和中间丝结蛋白免疫细胞化学染色阳性。结论:体外培养的大鼠眼外肌卫星细胞具有良好的增殖与分化能力,其生物学特征同骨骼肌卫星细胞。     

Augmentation of spontaneous macrophage-mediated cytolysis by eosinophil peroxidase

Eosinophil peroxidase (EPO), a cationic protein purified from horse blood, adhered to four different types of tumor cells, markedly potentiating their lysis by preformed or enzymatically generated H(2)0(2) (up to 76-fold, as assayed in serum-containing tissue culture medium without supplemental halide). Similarly, compared with uncoated tumor cells, EPO-coated tumor cells were up to 32 times more sensitive to lysis when incubated with macrophages or granulocytes whose respiratory burst was triggered by PMA. However, EPO-coated tumor cells were also readily lysed by bacillus Calmette- Guerin-activated macrophages in the absence of exogenous triggering agents. This spontaneous cytolysis was rapid (50 percent at 2 h) and potent (50 percent lysis at macrophage/tumor cell ratios of 1.5 to 4.6), and was observed with both a peroxide-sensitive tumor (TLX9) and a peroxide-resistant tumor (NK lymphoma). Under the conditions used, neither EPO alone nor macrophages alone were spontaneously cytolytic. Neither EPO nor EPO-coated tumor cells triggered a detectable increment in H(2)0(2) release from macrophages. Nonetheless, spontaneous macrophage-mediated cytolysis of EPO- coated tumor cells was completely inhibitable by catalase (50 percent inhibition, 23 U/ml), although not by heated catalase, indicating a requirement for H(2)0(2). Cytolysis was also completely inhibitable by azide (50 percent inhibition, 2.6 X 10 -5 M), indicating a requirement for enzymatic activity of EPO. Thus, a cytophilic peroxidase from eosinophils and H(2)0(2) spontaneously released from activated macrophages interacted synergistically in a physiologic medium to destroy tumor cells.     

低氧训练对下丘脑-垂体-肾上腺皮质轴内分泌相关激素的影响

目的:总结低氧训练对下丘脑-垂体-肾上腺皮质轴内分泌相关激素的影响,为科学运动训练提供依据。资料来源:应用计算机检索中国期刊全文数据库1994-01/2006-10的相关文章,检索词"低氧,低氧训练,下丘脑-垂体-肾上腺,激素",并限定文章语言种类为中文。并应用计算机检索美国国立医学图书馆NCBI1980-01/2006-10的相关文章,检索词"Hypoxic Training,organism endocrine system,hormone",并限定文章语言种类为English。资料选择:对资料进行初审,选取低氧训练与下丘脑-垂体-肾上腺分泌的相关激素有关的文献,并作初步分类,同类文献首选近年发表的核心期刊文章。排除重复及综述类文献。资料提炼:共收集到95篇相关文章,其中56篇属于重复及综述类文献,对符合标准38篇文献进行分析整理。资料综合:①高海拔状态下机体对低氧产生应激反应,表现为下丘脑-垂体-肾上腺皮质轴的适应性运转,血中促肾上腺皮质激素浓度增加,以调节机体对应激刺激的适应能力,同时使促肾上腺皮质激素释放因子分泌增加。②高原训练后,睾酮和皮质醇的变化都较明显,其总体变化均趋于降低,睾酮/皮质醇值有升有降,从一定意义上反映了机体的机能状况与疲劳积累程度。③低氧还引起大鼠血浆β-内啡肽浓度升高,可使心房钠尿素增加、前列腺素增加、血管内皮素分泌增加及抑制血管内皮舒张因子的分泌。结论:激素对机体的新陈代谢、生长发育、各种功能活动以及维持内环境稳态等方面发挥重要的调节作用,低氧训练对机体激素的影响一直应该受到人们的关注。     

The first wave of pandemic influenza (H1N1) 2009 in Germany: From initiation to acceleration

Background  

The first imported case of pandemic influenza (H1N1) 2009 in Germany was confirmed in April 2009. However, the first wave with measurable burden of disease started only in October 2009. The basic epidemiological and clinical characteristics of the pandemic were analysed in order to understand the course of the pandemic in Germany.