Criteria for the notification of childhood tuberculosis in a high-incidence area of the western Cape Province

The medical records of 124 children notified from Ravensmead Clinic, Parow, as having tuberculosis during 1987 were reviewed in order to determine the strength of the evidence on which the diagnosis was made. Arranging the diagnostic criteria in an hierarchical manner, as suggested by the World Health Organisation, the cases were categorised as suspect, probable or confirmed. Twenty-five were suspect cases (20%), 89 probable cases (72%) and the remaining 10 confirmed cases (8%). These findings indicated that notifications from the clinic were being made in accordance with internationally accepted practice. The use of the WHO approach for the categorisation of childhood tuberculosis cases is recommended for both clinical and epidemiological purposes.     

The synthesis and localization of alternatively spliced fibronectin EIIIB in resting and thrombin-treated megakaryocytes

There are several species of alternatively spliced fibronectin (FN). One of these, FN EIIIB, is primarily present in embryonic and in proliferating and migrating cells and is believed to be important for cell maturation. We have studied the synthesis, localization, and secretion of this FN isoform in isolated guinea pig megakaryocytes, nonmegakaryocytic bone marrow cells, and platelets. There was 7.5 times more general FN in megakaryocytes than in nonmegakaryocytic cells based on the analysis of equivalent amounts of protein. FN EIIIB was detected by Western blotting in megakaryocytes but not in nonmegakaryocytic cells present in bone marrow. Neither megakaryocytes nor platelets secreted FN EIIIB, while megakaryocytes secreted 25.3% +/- 4.6% general FN and platelets secreted about 61% general FN in response to thrombin. Analysis of immunostained cells by confocal microscopy revealed that FN EIIIB had been redistributed to the surface of megakaryocytes in response to thrombin. Synthesis was studied by metabolic labeling, and megakaryocytes were shown to synthesize FN and FN EIIIB. Thus, megakaryocytes and platelets are among a small number of adult cells and tissues that synthesize and contain FN EIIIB. The expression of FN EIIIB on the megakaryocyte surface may influence migration and maturation.     

Outbreak of serogroup C meningococcal disease caused by a variant of Neisseria meningitidis serotype 2a ET-15 in a community of men who have sex with men

We describe an outbreak, in a community of men who have sex with men, of serogroup C meningococcal disease caused by a genetic variant of the serotype 2a ET-15 Neisseria meningitidis characterized by a point mutation in the gene coding for the serotype 2a antigen. A microbiological characterization of the outbreak strain is presented in this report.     

稳定层流剪应力对内皮细胞骨架调节蛋白VASP表达的影响

为探讨生理强度的稳定层流剪应力对内皮细胞骨架actin相关蛋白VASP特征影响规律，我们采用胰蛋白酶消化法分离人脐静脉内皮细胞(HUVECs)，模拟体内流动环境，建立平行板流动腔模型。利用细胞图像分析系统和ALEXA488—若丹明一次毒蕈环肽双标记法，观察内皮细胞在稳态层流下形态、actin排列变化与VASP分布变化之间的规律。采用Western blot定量动态检测细胞内VASP表达及磷酸化的水平。结果表明，内皮细胞在10dyn／cm^2剪切作用后，随时间细胞逐渐延长，长轴趋于剪应力作用方向排列，细胞与静息态的细胞相比，细胞内骨架沿剪应力方向重组，与此同时VASP表达增强，沿着actin纤维呈点状分布，尤其集中在细胞膜下actin末端区域；Western blot检测显示在剪切后，细胞内VASP出现快速磷酸化，VASP总体表达量增加，2h达高峰后逐渐恢复，8h后再次逐渐升高。以上结果提示血流动力学特性中剪应力引起了细胞胞质内骨架蛋白分子重组，血管内皮细胞形态改变，在此过程中，VASP发挥骨架调节蛋白的作用。