Functional beta-cells derived from umbilical cord blood mesenchymal stem cells for curing rats with streptozotocin-induced diabetes mellitus

INTRODUCTIONThis study aimed to investigate the therapeutic response to injected human umbilical cord blood mesenchymal stem cells (UCBMSCs) among albino rats with streptozotocin (STZ)-induced diabetes mellitus.METHODSControl group (GI; n = 25) rats were fed with standard rat diet. Rats with STZ-induced diabetes mellitus without (GII; n = 25) and with (GIII; n = 25) differentiated human UCBMSCs implantation were the test groups. Rats were sacrificed in Week 11 following implantation. Liver biopsies were sectioned and stained in order to highlight both the presence and function of impregnated cells in the liver tissue.RESULTSHaematoxylin and eosin-stained sections in GI and GII rats showed normal liver architecture while GIII rats showed presence of cell clusters inside the liver tissue and around the central veins. Cell clusters with blue cytoplasm were present in sections in GIII rats but absent in GI and GII rats, indicating the presence of injected differentiated human UCBMSCs. The anti-human insulin immunostaining of GIII rats showed clusters of cells within the liver parenchyma and around central veins, indicating that these cells were active and secreting insulin.CONCLUSIONUCBMSCs are proficient in differentiating into insulin-producing cells in vivo under specific conditions and, when transplanted into the liver of albino rats with STZ-induced diabetes mellitus, were able to secrete insulin and partially control the status of diabetes mellitus in rats.     

Induction of erythroid differentiation in K562 cells and natural killer cell-mediated lysis: distinct effects at the level of recognition and lysis in relation to target cell proliferation

The erythroleukemic K562 cell line was induced to erythroid differentiation by a variety of agents, including hemin, bleomycin, and cytosine arabinoside. The sensitivity of induced cells to binding and lysis by non-sensitized peripheral blood mononuclear cells (MNC) in agarose was studied in relation to the target cell division rate. Differentiated K562 cells formed a lower proportion of conjugates with MNC, when compared with non-induced controls. The reduction correlated significantly with the level of differentiation, irrespective of the inducer and the proliferative status. The differentiation-induced alterations of lysis, however, were strongly influenced by the modification of target cell growth rate which was caused by the differentiating agent. These data suggest that target cell differentiation has distinct effects upon the steps of recognition and lysis by natural killer cells.     

Sputum microbiome profiles identify severe asthma phenotypes of relative stability at 12 to 18 months

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LFA-1-dependent OKT3-driven T cell clusters in common variable immunodeficiency.

The triggering of the TCR/CD3 complex by anti-CD3 (OKT3) antibody leads to the formation of T cell clusters. In cultures of T lymphocytes from most normal individuals, the peak of cluster formation occurs at 24 h, but with cells from patients with common variable immunodeficiency (CVI) it was seen earlier at 4-9 h; in addition, the clusters were larger than normal, particularly at 9 h. Cluster formation by CVI and normal cells was dependent on temperature and divalent cations, but did not require Fc receptors. Since OKT3 clustering is known to be dependent on the LFA-1/ICAM-1 adhesion system, the effect of monoclonal antibodies directed against these molecules was tested. A potent inhibitor was the antibody against the common beta chain of the integrin family (CD18), but of four MoAbs against the alpha chains (CD11), three inhibited and one stimulated T cell aggregate formation. Increased expression of LFA-1 or ICAM-1 on CVI patients' T cells could not be demonstrated. The accelerated clustering was therefore probably due to an increase in the proportion of cells carrying the activated form of LFA-1. The formation of large numbers of homotypic lymphocyte clusters might reduce the effective interaction between B and T cells, thus contributing to the depression of immunoglobulin synthesis observed in this disease.     

Ultrastructural histochemistry of mesotheliomas and adenocarcinomas in malignant effusions

The results of electron microscopic examination of cytologic specimens from six cases of mesothelioma and 10 cases of metastatic carcinoma of different origins are presented. The formation of cell clusters in malignant effusions from the two neoplasms has been thoroughly investigated: in mesotheliomas, cells had longer, more slender microvilli than in carcinomas and more abundant bundles of intermediate filaments; the central cavity often seen in the clusters frequently contained collagen and showed basement membrane production. The application of periodic acid-silver methenamine (PASM) and phosphotungstic acid (PTA) demonstrated a peculiar ultrastructural difference in cell coat staining in the two tumor types: in mesotheliomas, PTA and PASM were consistently negative along the outer surface of the cell aggregates, while carcinomas displayed a positive reaction either on the outer surface or on both inner and outer surfaces of the clusters. The diagnostic significance of the above-mentioned difference between the two neoplasms will require further investigation in a larger number of cases.     

产业集群竞争力理论的演变

西方产业集群理论中对产业集群竞争力分析最为著名的有马歇尔的外部经济理论、克鲁格曼的新经济地理学理论和波特新竞争优势理论等。马歇尔是从新古典经济学的角度,通过研究工业组织这种生产要素,间接表明了企业为了追求外部规模经济而集聚。克鲁格曼的新经济地理学产业群模型从理论上证明了制造业(工业)活动倾向于空间集聚的一般性趋势,并阐明由于外在环境的限制,产业区集聚的空间格局可以是多样的,产业集聚空间格局的形成及锁定效应,是经济活动收益递增和运输成本相互作用的产物。迈克尔·波特从组织变革、价值链、经济效率和柔性方面所创造的竞争优势角度重新审视产业集群的形成机理和价值,并提出了国家竞争优势的“钻石模型”。产业集群竞争力理论随着产业集群的不断发展而相应地演变成系统的理论体系,并不断为全球化背景下的区域发展提供新的政策和管制思路。     

The Calculation of Radiation Dose from Distributed Sources of Tritium

Summary

Formulae derived by Rossi and Ellis (1950) for the calculation of radiation dose from distributed sources of beta-emitters have been made applicable to the case of tritium by a consideration of the appropriate value for the effective absorption coefficient employed in these expressions. An example is given of their application to the calculation of dose to a cell from tritium incorporated in the nucleus.     

Health workforce planning in Europe: Creating learning country clusters

In this article, the different dimensions and determinants of health workforce planning (HWF) are investigated to improve context-sensitivity and mutual learning among groups of countries with similar HWF characteristics. A novel approach to scoring countries according to their HFW characteristics and type of planning is introduced using data collected in 2012 by a large European Union project involving 35 European countries (the ‘Matrix Study’ [8]). HWF planning is measured in terms of three major dimensions: (1) data infrastructure to monitor the capacities and dynamics of health workforces, (2) the institutions involved in defining and implementing labour market regulations, and (3) the availability of models to estimate supply–demand gaps and to forecast imbalances. The result shows that the three dimensions of HWF planning are weakly interrelated, indicating that countries invest in HWF in different ways. Determinant analysis shows that countries with larger health labour markets, National Healthcare Service (NHS), mobility, and strong primary health care score higher on HWF planning dimensions than others. Consequently, the results suggest that clustering countries with similar conditions in terms of HWF planning is a way forward towards mutual and contextual learning.