The appearance and role of gamma delta T cells in the peritoneal cavity and liver during primary infection with Listeria monocytogenes in rats.

We have previously reported that gamma delta T cells play important roles in protection during the early stage of infection with Listeria monocytogenes in mice. To generalize the protective roles of gamma delta T cells in listerial infection to different species, we examined the appearance of gamma delta T cells during infection with L. monocytogenes in Fisher F344 rats. The numbers of bacteria in the peritoneal cavity and liver increased to a maximum level on day 3 and then decreased to an undetectable level by day 10 after an intraperitoneal infection with a sublethal dose (1 x 10(8)) of viable L. monocytogenes in rats. CD3+ alpha beta- T cells in the peritoneal cavity and liver began to increase on day 3, reached a maximum level on day 6, and thereafter decreased gradually by day 10 after infection. Northern blot analysis confirmed that the CD3+ alpha beta- T cells expressed TCR delta and gamma gene messages. In vivo treatment with anti-TCR alpha beta mAb, which suppressed most of the alpha beta T cells in the periphery and impaired resistance during the late stage of listerial infection, did not affect the host defense by day 6 after infection. A significantly increased number of gamma delta T cells was detected in the peritoneal cavity of the TCR alpha beta-suppressed rats on day 6 after infection. These results suggest that the early appearing gamma delta T cells may contribute to the host defense at a relatively early stage during listeriosis in rats.     

Scanning electron microscopic studies of reticular framework in the rat mesenteric lymph node

Background: The reticular framework in the lymph node has in the past been studied mainly by light microscopy of silver-impregnated specimens. The aim of the present study is to understand three-dimensionally the ultrastructure and organization of the reticular framework better than before. Methods: The mesenteric lymph nodes of the rat were prepared either an alkali-water maceration method or a conventional method and were observed in a scanning electron microscope (SEM). Results: The SEM study of alkali-water macerated tissues visualized directly the reticular fiber network in the lymph node. The reticular fibers consisted of thin bundles of collagem fibrils. They were continuous with the collagen fibriliar sheaths of blood vessels and lymphatic sinuses as well as with the fibrous capusule, thus acting as a skeleton of the lymph node. The arrangement of the reticulum was variable, depending on individual compartments. The SEM study of conventionally treated tissues, on the other hand, clarified the shape of reticular cells and their relationship with the reticular fibers. The sinus reticular cells connected with the sinus lining cells but separated from the parenchymal reticular cells, indicating that the former two originate from lymphatic endothelial cells. The parenchymal reticular cells varied in shape depending on their locations but essentially shared features with fibroblasts. Conclusions: The arrangements of the reticular fibers in the parenchyma were closely related to the associated reticular cells, showing the possibility that the reticular cells maintain the shape of the reticular framework suitable for each compartment of the lymph node. © 1995 Wiley-Liss, Inc.     

Human papovavirus in a routine urine specimen of a four-year-old boy

Cellular changes produced by viruses can be readily identified using light microscopy and Papanicolaou stain of a fixed specimen. These findings can then be confirmed by viral culture and/or electron microscopy studies. Human polyomavirus, common in transplant recipients or otherwise immunocompromised patients, is one virus that can be identified using these methods. The following is a case study of a 4-yr-old boy with no known immune impairment who exhibited human papovavirus (polyomavirus) on a routine urine examination. The diagnosis was confirmed by electron microscopy.     

Infection of human epithelial cells by Epstein-Barr virus (EBV). II. Biochemical characterization of EBV-determined proteins synthesized in epithelial cells

Primary cultures of epithelial cells were grown from tonsils of patients with diseases not related to EBV. The cells were implanted with EBV receptors and exposed to EBV of the transforming (B95-8, AG-876) and nontransforming (P3HR-1) strains. The EBV-infected and control cells were pulsed with [35S]methionine at 18-24 h after infection, and cell extracts were prepared for immunoprecipitation with anti-EBV sera and analysis by gel electrophoresis and autoradiography. About 20 EBV-determined proteins ranging from 22 to 185 kDa were detected in P3HR-1 virus-infected epithelial cells. Only a few polypeptides were detected in extracts of cells infected with AG-876 virus while no EBV-specific proteins were immunoprecipitated from extracts of B95-8 virus-infected cells. These results demonstrate that the system of EBV receptor-implanted normal human epithelial cells can be used for direct biochemical analysis of EBV infection in the epithelial tissue.     

Functional expression and properties of the human skeletal muscle sodium channel

Full-length deoxyribonucleic acid, complementary (cDNA) constructs encoding the-subunit of the adult human skeletal muscle Na⁺ channel, hSkM1, were prepared. Functional expression was studied by electrophysiological recordings from cRNA-injectedXenopus oocytes and from transiently transfected tsA201 cells. The Na⁺ currents of hSkM1 had abnormally slow inactivation kinetics in oocytes, but relatively normal kinetics when expressed in the mammalian cell line. The inactivation kinetics of Na⁺ currents in oocytes, during a depolarization, were fitted by a weighted sum of two decaying exponentials. The time constant of the fast component was comparable to that of the single component observed in mammalian cells. The block of hSkM1 Na⁺ currents by the extracellular toxins tetrodotoxin (TTX) and -conotoxin (CTX) was measured. The IC₅₀ values were 25 nM (TTX) and 1.2 M (CTX) in oocytes. The potency of TTX is similar to that observed for the rat homolog rSkM1, but the potency of CTX is 22-fold lower in hSkM1, primarily due to a higher rate of toxin dissociation in hSkM1. Single-channel recordings were obtained from outside-out patches of oocytes expressing hSkM1. The single-channel conductance, 24.9 pS, is similar to that observed for rSkM1 expressed in oocytes.     

Review of the mutagenicity of ethylene oxide

Ethylene oxide has been shown to be an effective mutagen in a variety of organisms ranging from bacteria to mammalian cells. There is also an association between ethylene oxide exposure and human somatic cell cytogenetic damage. Furthermore, ethylene oxide has been shown to alkylate protein and DNA at exposure levels that have been encountered occupationally. Ethylene oxide is not only effective at producing somatic cell mutations but also at inducing genetic damage in germ cells. While it is clear that ethylene oxide is a germ cell mutagen in whole mammals, the mechanism(s) by which it produces genetic lesions in germ cells is uncertain.     

Recombinant interferon alpha 2 stimulation of target-binding by natural killer cells

Summary Even though the enhancement of the lyitc capacity and the kinetics of lysis of natural killer cells (NK) by interferon has been well documented, an increase of the target-effector cell binding percentage is still disputed. We, therefore, modified the Grimm-Bonavida single-cell assay so that 400 to 600 cells per individual determination could be reliably evaluated. Using this assay, which makes possible separate determination of effector-target cell binding and target lysis, we demonstrated that, in addition to lytic capacity, target-effector cell binding is also increased by preincubating NK with 100 to 1,000 IU interferon alpha 2 per 10⁶ cells. Our data indicate that interferon alpha 2 induces pre-NK cells to bind target cells and that it activates these pre-NK cells to kill the targets.Abbreviations NK Natural killer cells - LCMV Lymphocytic choriomeningitis virus - IFN Interferon - FCS Fetal calf serum - RPMI 1640 Culture medium Dedicated to Prof. H.D. Waller on the occasion of his 60^th birthday     

Morphological variability, lectin binding and Na+,K+-activated adenosine triphosphatase activity of isolated Müller (glial) cells from the rabbit retina

Rabbit retinal Müller cells were isolated by means of papaine and mechanical dissociation. These cells were shown to have a well preserved morphology and to preserve viability for many hours. Intense wheat germ agglutinin binding occurs on the photoreceptor side of Müller cells, especially in the microvillous region. Rabbit retinal Müller cells have a Na+,K+-activated adenosine triphosphatase activity in the same order of magnitude as brain astroglial cells.     

Molecular mechanisms of virus-induced carcinogenesis: the interaction of viral factors with cellular tumor suppressor proteins

Accumulating evidence indicates that tumor viruses represent a major etiological factor in a significant portion of human cancers. These cancers include human papillomavirus induced anogenital cancers, hepatitis B and C virus associated hepatocellular carcinomas, nasopharyngeal carcinomas and lymphomas linked to Epstein-Barr virus infection, and human T cell leukemia virus associated adult T cell leukemias. This review summarizes the recent progress made in understanding the molecular mechanisms of viral carcinogenesis, with a particular focus on the interaction of viral factors with cellular tumor suppressor proteins. The functional inactivation of tumor suppressor proteins may represent a common strategy by which several tumor viruses contribute to malignant cell transformation.Abbreviations EBV Epstein-Barr virus - E6AP E6-associated protein - HBV Hepatitis B virus - HCC Hepatocellular carcinoma - HPV Human papillomavirus - HTLV Human T cell leukemia virus - pRb Retinoblastoma protein - RB Retinoblastoma - SV40 Simian virus 40     

骨髓间充质干细胞与自体腹膜联合修复盆腔自主神经损伤的实验研究

目的观察骨髓间充质干细胞(BMSC)与自体腹膜桥接管联合移植修复盆腔自主神经损伤的效果.方法建立比格犬盆腔自主神经损伤模型,实验组以自体腹膜管填充胶原蛋白海绵+BMSC桥接于缺损神经两端;对照组改BMSC为生理盐水.正常对照组为自体神经移植.术后12周取材,标本切片行HE染色和神经纤维(NF)免疫组化染色.应用图像分析系统对选定数据进行测量.透射电镜观察实验组再生神经纤维超微结构.结果实验组与对照组比较再生神经纤维总数[(1742±185)根比(1131±262)根,P<0.01]、密度[(168±14)根/104μm2比(124±17)根/104μm2,P<0.01]、直径[3.83±0.22)μm比(3.28±0.41)μm,P<0.05]、面积百分比(0.32±0.07比0.21±0.08,P<0.05)差异均有统计学意义,与正常对照组比较差异均无统计学意义(P>0.05).实验组再生神经纤维结构清晰,形态接近正常.结论 BMSC与自体腹膜桥接管联合移植修复盆腔自主神经缺损再生神经纤维生长好,方法可行,与自体神经移植修复效果相当.