水体中克雷伯菌属的分布及其在水源性急性肠道感染中的价值

俄罗斯不同气候地区不同功能水体中克雷伯菌属广泛分布。克雷伯菌属可见于遭受生物、化学污染的集中供水的地表水源,无防护的地下蓄水层,缺乏有效清洁、消毒系统的饮用水。研究表明,水体中的克雷伯菌属具有致病性和毒性,对现代药物和消毒剂(氯、紫外线)具有抗性,很容易穿透进入地下蓄水层。克雷伯菌属细菌有很强的致病性(粘附力、侵袭力、磷酸酯酶、卵磷脂酶、脱氧核糖核酸酶、溶血活性),含有致病性遗传标记cnf-1。克雷伯菌属(100 CFU/dm³)可引起急性肠道感染。在不检测总大肠菌群的情况下,检测水体尤其是饮用水中的克雷伯菌属,可以评估所用水的流行病学危险。     

Cell cycle-dependent variation of a CD133 epitope in human embryonic stem cell, colon cancer, and melanoma cell lines

CD133 (Prominin1) is a pentaspan transmembrane glycoprotein expressed in several stem cell populations and cancers. Reactivity with an antibody (AC133) to a glycoslyated form of CD133 has been widely used for the enrichment of cells with tumor-initiating activity in xenograph transplantation assays. We have found by fluorescence-activated cell sorting that increased AC133 reactivity in human embryonic stem cells, colon cancer, and melanoma cells is correlated with increased DNA content and, reciprocally, that the least reactive cells are in the G(1)-G(0) portion of the cell cycle. Continued cultivation of cells sorted on the basis of high and low AC133 reactivity results in a normalization of the cell reactivity profiles, indicating that cells with low AC133 reactivity can generate highly reactive cells as they resume proliferation. The association of AC133 with actively cycling cells may contribute to the basis for enrichment for tumor-initiating activity.     

Epidemiology of persistent diarrhea among Guatemalan rural children

A prospective, longitudinal two-year study to determine the epidemiology of persistent ( 14 days'duration) diarrhea in rural children of Guatemala was undertaken. Three-hundred and twenty-one children aged 0-35 months were kept under surveillance by twice-a-week home visits. The overall incidence of diarrhea was 0.147 per child-week; the incidence of persistent diarrhea was 0.014 per child-week. The peak of persistent diarrhea was observed in infants below six months of age, with a continuous decline thereafter. This trend in incidence of persistent diarrhea was associated with a higher proportion (16%) of illnesses persisting for more than 13 days in children younger than six months of age as compared to children 30-35 months old (4%). Males had more diarrhea (0.156 per child-week) than females (0.139 per child week). Among children above 18 months of age, the proportion of episodes that lasted for more than 13 days was lower in females than in males.     

Autoerythrocyte sensitization syndrome (Gardner–Diamond syndrome): review of the literature**

A review of the literature concerning psychogenic purpura is presented. The diagnosis is usually based on typical anamnestic data, clinical presentation (painful inflammatory skin lesions, which progressed to ecchymoses during the next 24 h) and positive diagnostic tests with intracutaneous injections of 80% solution of washed autologous erythrocytes. No pathological findings of blood coagulation parameters are usually detected. Histopathological evaluations of lesional biopsies revealed non-specific changes. Taking into account the high frequency of psychic disorders and stress dependence of skin symptoms, therapy with psychotropic drugs (according to indications) and psychotherapy are pathogenetically grounded methods of treatment in psychogenic purpura, and should be provided together with symptomatic therapy.     

Hemoglobin M equon beta 41 (C7) phenylalanine leads to tyrosine

A severe hemolytic crisis was observed in a 34-yr-old female of English- Irish extraction following a viral illness treated with acetaminophen. Heinz bodies and heat instability were present only during a transient hemolytic event. A challenge dose of acetaminophen caused no detectable hematologic abnormality. Structural studies of the hemoglobin during hemolysis and again after complete recovery localized the abnormality to tryptic peptide beta Tp-5, and automated sequencing of I 125-labeled beta chains indicated a replacement of phenylalanine (C7) beta 41 by tyrosine. Substitution of the next residue, phenylalanine (CD1) beta 42 by serine (Hb Hammersmith), has resulted in chronic severe Heinz body hemolytic anemia. The lack of chronic anemia in the present disorder may reflect the different relationships of beta41 and beta 42 and/or the similarities in volume and hydrophobicity of tyrosine and phenylalanine. It is suggested that substitution of tyrosine for phenylalanine in Hb Mequon may disturb the critical environment around the heme group and render it susceptible to oxidative denaturation in the presence of infections and/or drugs.