Hydrophobic interactions in Plasmodium falciparum invasion into human erythrocytes

Human glycophorins block in vitro invasion of Plasmodium falciparum merozoites into human erythrocytes. A segment of glycophorin A which appears to be involved in the inhibition, is at, or adjacent to, the membrane-spanning domain of the molecule. To study the role of hydrophobic interactions in the inhibition, a series of proteins were derivatized with lipophilic side groups, and tested for inhibitory activity. Glycophorin A became five times more inhibitory after derivatization with nitrobenzylfurazan groups. Bovine serum albumin was derivatized to different degrees with nitrobenzylfurazan, dinitrobenzyl, trinitrobenzyl, dansyl, disulfonic stilbene, and fluorescein groups. The presence of hydrophobic side groups on the protein rendered it highly inhibitory to invasion, whereas the presence of hydrophilic substitutes such as disulfonic stilbenes did not. Other soluble proteins such as human serum albumin, transferrin, ovalbumin, fetuin and casein derivatized with dinitrobenzyl groups, were also found to block invasion. Inhibition was not a result of toxic effects of the protein derivatives on parasite metabolism or development. A minimum of ten hydrophobic side groups per bovine serum albumin was required in order to elicit appreciable inhibition. The invasion blocking activity was highly correlated with the rate and affinity of binding of the derivatized macromolecules to heptyl-Sepharose. The latter provided a quantitative measure for the capacity of amphiphiles to undergo hydrophobic interactions with insoluble matrices. The results of the present study indicate that hydrophobic interactions may be an essential component in the invasion of P. falciparum merozoites into human erythrocytes.     

T-cell specificity in murine autoimmune haemolytic anaemia induced by rat red blood cells

Autoimmune haemolytic anaemia (AIHA) can be induced in mice by repeated injections with rat red blood cells (RBC). Here we describe the identification of rat and murine RBC antigens recognized by T-cells from mice with this disease. Splenic T-cells from mice with AIHA proliferated in response to multiple murine RBC membrane components, each of which is recognized by rat RBC induced autoantibodies. Thus, there were responses to murine autoantigen fractions that correspond in apparent molecular mass with the anion channel Band 3, with spectrin from the membrane skeleton and with the high and low molecular mass glycophorins, and the equivalent fractions from rat RBC also stimulated proliferation by T-cells. It was confirmed that purified Band 3 from murine and rat RBC also elicited responses. In contrast with the results in AIHA, T-cells from healthy control mice failed to respond to the antigens from either species, with the exception of proliferation induced by murine spectrin in one experiment and weak responses elicited by rat Band 3. It is suggested that T-cells activated by multiple cross-reactions between rat and murine RBC proteins, and by epitope spreading, are necessary to drive autoantibody production in this model of AIHA.     

Demonstration of T4, T8, M1 and B7 determinants on human T cells with a rosette test: implications for the assay specificity of monoclonal antibodies

Under optimal test conditions significantly more freshly isolated human T cells reacted with OKT4, OKT8, OKM1 and OKB7 monoclonal antibodies (Mabs) in the indirect antiglobulin rosetting reaction (IARR) than by indirect immunofluorescence. Rabbit erythrocytes (E) coated with anti-mouse immunoglobulin were more sensitive indicator cells in the IARR than similarly coated sheep E. Treatment of T cells with neuraminidase further enhanced T cell reactivity in the IARR with each Mab so that an average of 60% or more of T cells were T4+, T8+ and M1+ and at least 40% had the T4+ T8+ phenotype. The various findings suggest that the rosette assay detects determinants on T cells that are expressed below the detection threshold of immunofluorescence. Moreover, these findings indicate that the cellular specificities of a particular Mab may change when one assay system is substituted for another or when the protocol of a particular assay is altered.     

慢性肾功能衰竭红细胞变形能力与红细胞膜的研究

本文报道了慢性肾功能衰竭患者红细胞的变形能力、红细胞膜胆固醇与磷脂比值及膜微粘度。结果表明,红细胞可变形能力明显降低,膜胆固醇与磷脂比值及膜微粘度明显增加,提示红细胞变形能力可能与红细胞膜的流动性有关。     

Reticular and plexiform perineurioma: clinicopathological and immunohistochemical analysis of two cases and review of perineurial neoplasms of skin and soft tissues

Perineurioma represents a recently described and relatively rare neoplasm in the spectrum of benign peripheral nerve sheath tumours composed of perineurial cells staining immunohistochemically positive for epithelial membrane antigen (EMA). In addition to intraneural, extraneural and sclerosing perineurioma, rare variants of perineurioma may occur, and their knowledge is important in the differential diagnosis of mesenchymal tumours of different lines of differentiation and clinically more aggressive neoplasms. We present a case of deep-seated reticular perineurioma arising on the upper arm of a 34-year-old female and a case of a dermal plexiform perineurioma arising on the lower lip of a 60-year-old female. The diagnosis was confirmed in both cases immunohistochemically; neoplastic cells stained positively for EMA and for the newly described perineurial markers, claudin-1 and glut-1. The morphological spectrum and the differential diagnosis of perineurial neoplasms of skin and soft tissues are discussed.     

The Follow-Up Study of Skin Reactivity to Recall Antigens and E- and EAC-RFC Profiles in Blood in Asbestos Workers

We have determined cutaneous DTH reactions to SK-SD and PPD and peripheral blood lymphocyte profiles in a group of asbestos workers in two consecutive surveys. It was found that asbestosis and, to a lesser extent, the presence of ANA are significantly correlated with the lack of response to the above antigens. 83% of asbestos workers when tested at a 4 year interval fell into the same two categories of responsiveness (lack of response or response at least to one antigen).The asbestosis cases had lower total lymphocyte count as well as proportions and absolute number of E-RFC as compared to asbestos workers without asbestosis and/or ANA. Furthermore, the latter group showed the lower percentages and absolute number of E-RFC than the matched controls. The presence of ANA is also correlated with lower proportions of E-RFC. However, this is related at least in part to asbestosis.     

红细胞变形性的影响因素及测量方法

红细胞的变形能力是一种重要的流变现象，是影响血液循环的主要因素，具有重要的生理学意义。红细胞的变形能力是某些疾病的重要特征。本文从内部因素、外部因素和其他因素三个方面，介绍了小同因素对红细胞变形性的影响，并比较、讨论了测量红细胞变形性的主要方法。     

肝硬化患者红细胞内镁测定及其临床意义

目的　探讨肝硬化肝功能失代偿期患者红细胞内镁含量的变化及其临床意义。方法　研究对象为 32例肝硬化患者 ,按Child -Pugh分级法计肝功能B级 14例 ,C级 18例 ,合并肝性脑病 9例。对照组 5 9例为首次义务献血者。采用原子吸收光谱法测定受试者静脉血红细胞内镁浓度。结果　肝硬化组与对照组红细胞内镁浓度比较差异有非常显著意义 (P <0 .0 1)。肝硬化肝功能B级、C级红细胞内镁浓度与正常对照组比较均有非常显著差异 (P <0 .0 5 ,P <0 .0 1)。肝硬化合并肝性脑病 9例 ,其红细胞内镁浓度与C级无肝性脑病者比较 ,差异有非常显著意义 (P <0 .0 1)。结论　肝硬化患者红细胞内镁浓度的变化与肝性脑病的发生有一定关系。     

活性氧对红细胞膜流动性影响的研究

目的 :研究活性氧诱导红细胞发生氧化溶血的机制。方法 :用不同浓度的 H2 O2 作用于离体正常红细胞 ,分别用比色法、硫代巴比妥酸荧光法、荧光偏振法测定红细胞溶血度、红细胞膜脂质过氧化物 (L PO)、红细胞膜微粘度。结果 :5 0 ,10 0 ,12 0 mm ol/ L 浓度的 H2 O2 作用于红细胞后 ,均引起红细胞发生氧化溶血 ,红细胞溶血度、红细胞膜 L PO、红细胞膜微粘度均明显增加 ;H2 O2 在 5 0～ 12 0 mm ol· L- 1浓度范围内 ,红细胞溶血度、红细胞膜 L PO、红细胞膜微粘度的增加与 H2 O2 有明显的量效关系 ;红细胞膜微粘度与红细胞溶血度呈明显正相关 ,红细胞膜 L PO与红细胞膜微粘度呈明显正关。结论 :活性氧引发红细胞膜脂质过氧化导致红细胞膜流动性降低在活性氧诱导红细胞发生氧化溶血的机制中起一定的作用     

红细胞免疫作用对胃癌细胞凋亡影响的初步研究

目的探讨红细胞免疫作用对胃癌BGC - 82 3细胞凋亡的影响 ,以及淋巴细胞的协同作用。方法应用红细胞免疫粘附肿瘤细胞花环试验、流式细胞术及放射免疫等方法 ,采用正常人外周血红细胞及红细胞 -淋巴细胞免疫粘附人胃腺癌BGC - 82 3细胞 ,检测红细胞及红细胞 -淋巴细胞免疫粘附胃癌细胞花环率 -胃癌细胞凋亡率、凋亡相关基因Fas、Bcl- 2以及凋亡相关信号传导物质cAMP、PKC的变化。结果红细胞组肿瘤红细胞花环率为 (2 8.41± 5 .0 1) % ,与对照组比较 ,红细胞组胃癌细胞凋亡率、Fas基因的表达、胃癌细胞内cAMP水平显著升高 ,蛋白激酶C(proteinkinaseC ,PKC)水平显著降低 (P <0 .0 1) ;与红细胞组相比 ,红淋混合组总花环率、胃癌细胞凋亡率、胃癌细胞内cAMP水平进一步增高 ,Bcl- 2基因的表达及PKC水平降低更为显著 (P <0 .0 1)。结论正常人红细胞可免疫粘附体外培养的胃癌BGC - 82 3细胞 ,通过红细胞的免疫作用 ,尤其是免疫粘附 ,可增加凋亡相关基因Fas的表达 ,增高胃癌细胞内cAMP水平 ,降低PKC水平 ,从而可能在诱导胃癌细胞凋亡方面起到某种作用 ;自身淋巴细胞有不同程度的促进和协同作用。