Epidemiology and virulence gene expression of intracellular group A streptococci in tonsils of recurrently infected adults

Intracellularly persistent group A streptococci (GAS, Streptococcus pyogenes) have been associated with recurrent tonsillopharyngitis and antibiotic treatment failure. As a supplementation of the published in vitro data, conventional bacteriology and molecular epidemiology was performed on material from 29 adult patients of a German army hospital with anamnestic signs of recurrent tonsillopharyngitis. Pre-surgery tonsil swabs and the surgically removed tonsils were examined with respect to growth of aerobic bacteria in absence and presence of antibiotics with exclusively extracellular activity. Under such antibiotic selection, Staphylococcus aureus and GAS were cultured from specimens of 13 and 3 patients, respectively. In every material GAS-positive by culture methods, the intracellular location of the penicillin-susceptible GAS isolates was confirmed by immunohistologic examination of tonsillar sections using a GAS-specific IgG antibody. The three intracellular GAS isolates were typed by emm gene sequencing and could be associated to types M6 and M49 (two isolates). The bacteria were serially passaged on sheep blood agar, and semiquantitative mRNA analysis from virulence genes was performed using bacteria of the 4th and 25th passage after isolation. An M-type-specific pattern of virulence gene expression and different gene expression levels in relation to the passage number were observed.     

Differential effects of zidovudine and zidovudine triphosphate on mitochondrial permeability transition and oxidative phosphorylation

1. The effects of zidovudine (ZDV) and zidovudine triphosphate (ZDV-3P) on Ca²⁺-induced mitochondrial permeability transition (MPT), respiratory control ratio (RCR) and ATP synthesis have been investigated on isolated rat liver mitochondria.
2. ZDV slightly but significantly decreased RCR and ATP synthesis but was ineffective in inhibiting MPT. In contrast, ZDV-3P did not alter RCR and ATP synthesis but strongly inhibited MPT (IC₅₀=3.0±0.9 μM).
3. The effect of ZDV-3P on mitochondrial swelling required a preincubation time. When incubated 10 min with mitochondria, ZDV-3P (8 μM) totally inhibited the rate of swelling.
4. ADP, ATP and atractyloside, which are agents known to interact with the mitochondrial adenine nucleotide carrier (ANC), antagonized the effect of ZDV-3P on mitochondrial swelling. Indeed, the IC₅₀ value of ZDV-3P increased from 3.0 to 17.4, 93.6 and 66.5 μM, in the presence of 20 μM, ADP, ATP or atractyloside, respectively.
5. ZDV-3P did not displace [³H]-ATP from its mitochondrial binding site(s) whereas ADP and atractyloside did, suggesting that ZDV-3P and [³H]-ATP do not share the same binding sites.
6. ZDV-3P did not affect either mitochondrial respiration or ATP synthesis but inhibited Ca²⁺-dependent mitochondrial swelling. It was concluded that mitochondrial toxic effects observed during the chronic administration of ZDV cannot be related to its active metabolite (ZDV-3P).

     

广西壮族自治区部分地区1992～1993年新生儿乙型肝炎疫苗接种率和血清学效果调查

广西壮族自治区正在普遍推广乙型肝炎（乙肝）疫苗接种,为了解城市和农村乙肝疫苗的接种率和血清学效果,于1994～1995年在南宁等5个城市和农村三类地区,按容量比例概率抽样法,抽取1991年1月1日～1993年12月31日出生的儿童842人,调查乙肝疫苗接种率．结果5个城市均为100％,农村富裕地区为47.4o％,一般地区为39.3％,而贫困地区仅为18．1％．又以随机抽样的方法,在柳州等3个城市和5个地区,抽取1992年1月1日～1993年12月31日出生并全部接种了乙肝疫苗的儿童1459人,用固相放射免疫法检测执-HBs,用酶免疫法检测HBsAg和抗-HBc．结果1994年1～2岁儿童的HBsAg阳性率为1.7％,1986年的9.7％下降了82.5％。进一步提高农村地区,特别是贫困地区乙肝疫苗的接种率,是降低乙肝病毒携带和传播的关键。     

条件致病菌与非淋菌性尿道炎的关系初探

目的：为了解非淋菌性尿道炎和条件致病菌感染的关系。方法：采用常规细菌培养,Ｋ－Ｂ药敏试验法,支原体培养及衣原体直接免疫荧光染色法检测患者尿道分泌物或前泌物或前列腺液标本。结果：２３８例非淋菌性尿道炎病人标本中,细菌培养阳性２１１例（８８．６％）,支原体培养阳性３７例（１５．６％）,其中与细菌共同阳性３０例,衣原体阳性２４例（１０．８％）,其中与细菌共同阳性１４例,与念珠菌共同阳性１例,念珠菌阳性７     

HBV无症状携带者与ABO血型关系的探讨

目的：探讨ＨＢＶ无症状携带者与ＡＢＯ血型间关系。方法：采用Ｗｏｏｌｆ统计方法与卡方（ｘ＾２）检验方法对１７４例ＨＢＶ无症状携带者的ＡＢＯ血型分布以及男女性别的关系进行系统分析。结果：男性携带者血型呈Ｂ〉Ｏ〉Ａ〉ＡＢ型分布,女性携带者呈Ｂ〉Ａ〉Ｏ〉ＡＢ型分布。Ａ、Ｂ、Ｏ和ＡＢ血型人相对危险率分别是０．４８７０、２．０４１４、０．９６６８和１．７９５０。结论：ＨＢＶ无症状携带者与ＡＢＯ血型间存在一定关     

Effect of low concentrations of K+ and Cl− on the Na+-dependent neuronal uptake of [3H] dopamine

The specific uptake of [³H] dopamine (DA) was studied using a crude synaptosomal fraction obtained from rat striatum. In a medium containing a 10 mM NaHC03/NaH2PO4 buffer and no added K⁺ ions, addition of NaCl elicited an increase in DA uptake for Na⁺ concentrations from 10 to 60 mM, and then a decrease of uptake for Na⁺ concentrations up to 130 mM. These data confirm that rather low NaCl concentrations produce a maximal DA uptake. This biphasic curve of uptake resulted from significant changes in the V _max of the DA uptake. Except for 10 mM Na⁺, this curve was not significantly modified when 9 mM NaHCO₃/NaH₂PO₄ were replaced by 9 mM NaCl. This result indicates that the Cl^– dependence of the DA uptake is mainly secondary to the Na⁺ dependence. Addition of KCl up to 3 mM did not modify the ascending part of the NaCl-dependent uptake curve. In contrast, the reduction in uptake produced by high Na⁺ concentrations was prevented in a concentration-dependent manner by KCl; this effect resulted from a decrease in the K_m and an increase in the V _max for the uptake.Measurements of membrane potential, with the help of the fluorescent probe 3,3-diethylthiadicarbocyanine iodide [DiSC₂(5)] and purified synaptosomes prepared from rat striatum and cerebral cortex, revealed that addition of 3 mM KCl to a medium containing a high Na⁺ concentration and no K⁺ ions produced a marked and stable decrease in the fluorescence level. This decrease which corresponds to an increase in membrane polarization was blocked by 0.1 mM ouabain. These data suggest that low K⁺ concentrations are likely to prevent the decrease in uptake elicited by high Na⁺ concentrations by restoration, via a Na⁺/K⁺ ATPase-mediated mechanism, of the membrane potential and/or a transmembrane electrochemical Na⁺ gradient more favourable to DA uptake.     

DNA profiling of bloodstains on linen pretreated with remedies used for cleaning and maintaining clothes

Summary Linen was pretreated with 20 remedies for cleaning and maintaining clothes and 20 l blood was applied on each sample and dried. Restriction enzyme digest of bloodstain DNA was irregularly inhibited by highly concentrated residues of 2 detergents and a stainremover and colour-brightener. An additional dialysis step to purify DNA (Gill 1987) reliably prevented disturbance. High molecular DNA was obtained in every case and bandshifts were not observed.     

中药载体制剂的研究进展

总结近年来中药载体制剂的研究工作和文献报道，综述了有关脂质体、微粒、毫微粒、乳剂等作为载体在中药制剂中的应用。     

纳米载体药物应用的研究进展纳米载体药物应用的研究进展

载体药物是随着药物学研究、生物材料科学和临床医学的发展而新兴的给药技术。药物通过载体进入人体 ,载体对药物吸附、包裹和键合 ,使药物释放部位、速度和方式等具有选择性和可控性 ,实现药物的缓释和靶向传输 ,从而更好地发挥药物治疗效率。载体药物技术的关键是载体材料的选择 ,目前已有各种高分子材料和无机材料被用于载体药物的研究 ,但对材料的选择必须满足组织、血液、免疫等生物兼容性的要求[1] 。此外 ,载体药物的制备也很重要 ,因为这将影响到载体药物的给药效率。最近已有很多方法应用于这一领域 ,纳米技术的应用已引起关注。纳…     

O-羧甲基N-半乳糖化壳聚糖衍生物的设计、合成和表征

目的：合成和表征O-羧甲基-N-半乳糖化壳聚糖衍生物作为潜在的肝靶向基因载体。方法：以天然聚合物壳聚糖为原料，首先制备得O-羧甲基壳聚糖，然后在其2-NH2上和乳糖酸反应，制得O-羧甲基-N-乳糖酰化壳聚糖；或与乳糖反应，用KB}14还原，制得O-羧甲基-N-乳糖胺化壳聚糖。结果与结论：分别用VF-IR、^1H NMR、^13C NMR和元素分析对其进行了表征。用粉末X-衍射、DSC、TG对其物理性质进行了分析。制得的O-羧甲基-N-乳糖酰化壳聚糖O-羧甲基-N-乳糖胺化壳聚糖有望作为潜在的肝靶向基因载体。