Secretion of cathepsin B by human gliomas in vitro

There is evidence from investigations of non-CNS neoplasms that secreted proteolytic enzymes may facilitate tumour invasion by partially degrading extracellular matrix (ECM). Among the enzymes which may be involved are members of the cysteine proteinase superfamily and especially cathepsin B (CB). In the present investigation we have studied CB in human gliomas in vitro , concentrating particularly on CB secretion, as extracellular enzyme is of prime importance in this context. We have found that CB is secreted by gliomas in vitro as a latent zymogen, requiring activation. This has been confirmed by gel chromatography which indicated that CB is secreted as a 42 kDa proenzyme which may be proteolytically processed to an enzymatically active 29 kDa molecule. The inactive, high molecular weight, latent CB is stable at extracellular pH in contrast to the activated low molecular weight form which rapidly loses activity at this pH. We have also measured secretion of cysteine proteinase inhibitors (CPI), as their presence would have a direct influence on the effective activity of CB, and found that all of the gliomas secreted significant amounts of a CPI as assessed by papain inhibition. Our experiments suggest that a number of factors are involved in the regulation of extracellular glioma-derived CB activity. These include: rate of secretion of pro-CB, rate of CB activation, destabilization of CB at neutral pH and the presence of cysteine proteinase inhibitors.     

Acute urticaria and hepatitis complicating high-dose methotrexate therapy

We report an unusual case of anaphylaxis and hepatitic dysfunction in a child with the administration of the twenty-third course of high-dose methotrexate. The latter had been used as an adjuvant to prevent pulmonary metastases and the prior 22 courses had been well tolerated. An attempt to reinstate methotrexate after the twenty-third course was again followed by a similar reaction. © 1995 Wiley-Liss, Inc.     

神经肽Y对免疫细胞活性的影响

神经肽Y（NPY）是广泛分布于中枢神经系统和外周神经各部位的神经肽类物质。本实验观察NPY在体外对几种免疫细胞活性的直接作用。结果表明，NPY对小鼠T淋巴细胞丝裂原反应性和NK细胞的杀伤活性均无明显影响（P＞0．05），对巨噬细胞分泌溶菌酶有明显抑制作用（P＜0．05）；而对B淋巴细胞丝裂原反应性则有明显的促进作用（P＜0．05）。上述结果提示，NPY对部分免疫细胞功能的影响因细胞种类而异。     

广西急性散发性病毒性肝炎的血清流行病学研究

对广西１６６例住院急性散发性病毒性肝炎病毒性肝炎病例进行血清流行病学调查研究，结果表明，甲型，乙型，丙型，戊型，庚型肝炎生期感染指标检出率分别为４．８２％，５１．２０％，１３．８６％和１１．６４％，未分病例占１７．４２％，危险性因素分析表明，乙肝、丙肝和庚肝病人中有较高的肝病史、输血史和手术史。认为乙肝在急性散病毒性肝炎中占重要地位，医源性传播是主要传播途径 。     

巢式PCR检测先天性心脏病心脏石蜡标本中B19病毒的感染

目的：探讨微小病毒Ｂ１９与先天性心脏病（ＣＨＤ）的相关性及可能致畸机理。方法：采用病例对照研究，病例组为２９例ＣＨＤ尸解心脏组织，对照组为３０例同期非先天性畸形尸解心脏组织，应用巢式ＰＣＲ扩增Ｂ１９－ＤＮＡ，单纯疱疹病毒（ＨＳＶ），兔弓形虫（ＴＯＸ），巨细胞病毒（ＣＭＶ），结果：２９例ＣＨＤＢ１９－ＤＮＡ５例阳性，全瓿对照组为均阴性（Ｐ＝０．０２３７），ＨＳＶ，ＴＯＸ两组中均阴性，ＣＭＶ在两组中均     

硒和/或维生素E预防大鼠内皮细胞损伤的实验研究

用含硒（Ｓｅ０．５ｍｇ／ｋｇ）和／或维生素Ｅ（ＶＥ０．６ｇ／ｋｇ）的高脂饲料喂养成年雄性Ｗｉｓｔａｒ大鼠１２周。结果：高脂对照组大鼠血浆前列腺素Ｆｌα（６－酮－ＰＧＦ１α）水平下降，而血清脂质过氧化物（ＬＰＯ）、血浆血栓素（ＴＸＢ２）及内皮素（ＥＴ）水平上升；补Ｓｅ、ＶＥ及Ｓｅ＋ＶＥ可明显降低大鼠血清ＬＰＯ、血浆ＴＸＢ２、ＥＴ及ＴＸＢ２／６－酮－ＰＧＦ１α比值。同时，除了明显提高血浆谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活力外，血浆６－酮－ＰＧＦ１α浓度明显升高。实验提示，Ｓｅ和／或ＶＥ有调节花生四烯酸代谢及保护内皮细胞的作用。     

慢性乙型肝炎伴肝胆结石病人胆汁、外周静脉血、门静脉血中HBsAg和HBV-DNA的存在探讨

对29例慢性乙型肝炎伴肝胆结石患者.采用Elisa和斑点杂交技术检测外周静脉血、胆管胆汁和门静脉血中乙型肝炎两对半及HBV-DNA.并比较HkAg含量.结果，外周静脉血、胆汁和门静脉血中HBsAg浓度分别为;2244.73±59722ng／ml、1181.65±370.91ng／ml、2013.62±483.47ng／ml;HBV-DNA阳性检出率分别为62.07％（18例），72.41％（21例）及68.97％（20例）.提示肝细胞内复制的HHV在进入血循环的同时，部分随胆汁的分泌排入肠道，并可能通过受损肠粘膜进入门静脉再回到肝脏，造成HBV对肝脏的重复感染。     

Cholera Toxin B-Mediated Targeting of Lipid Vesicles Containing Ganglioside GM1 to Mucosal Epithelial Cells

Purpose. To determine whether the non-toxic pentameric B subunit of Cholera toxin (CTB) binding to ganglioside GM1 on both the lipid vesicles and epithelial cells may provide a means to target lipid vesicles to mucosal cells expressing surface GM1. Methods. Sonicated lipid vesicles containing ganglioside GM1 were prepared. Inter-vesicle cross-linking due to pentameric CTB binding to these GM1 vesicles was determined with a sub-micron particle analyzer. Association of CTB to GM1 vesicles was analyzed with continuous sucrose gradient centrifugation. CTB-mediated binding of GM1 vesicles to human mucosal epithelial cells (Caco-2 and HT-29), mucous membranes of mouse trachea, and nasal tissues were detected with fluorescent labeled vesicles. Results. An increase in lipid particle size due to binding of CTB to lipid vesicles and inter-vesicles cross-linking was detected. At a 30-to-1 mole ratio of membrane-bound GMl-to-CTB, optimum increase in GM1 vesicle aggregation, was detected. Under such conditions, all the added CTB molecules were associated with GM1 vesicles. Time course analysis showed that inter-vesicles cross linking by CTB was detectable within 10 min. and reached a maximum value at 60 min. CTB associated GM1-vesicles bind to mucosal epithelial cells HT-29 and Caco-2 with similar affinity [K_d = 7.8 × 10^–4 M lipid (Caco-2) and 7.6 × 10^–4 M lipid (HT-29)]. GM1 mediated binding specificity was demonstrated by blocking with anti-GMl antibody and the insignificant degree of CTB-associated GM1 vesicle binding to GM1 deficient C6 cells. Conclusions. The CTB-mediated GM1 binding to multiple membrane surfaces provides selective localization of GM1 vesicles to GM1 expressing mucosal cells and tissues. The strategy may be useful in localizing drugs and proteins to gut and respiratory tract mucosa.     

Spatially and Temporally Regulated Modification of the Receptor-like Protein Tvrosine Phosphatase ζ/β isoforms with Keratan Sulphate in the Developing Chick Brain

Protein tyrosine phosphatase ζ (PTPζRPTPβ) is a proteoglycan-type receptor-like protein tyrosine phosphatase specifically expressed in the brain. In addition to the transmembrane form (PTPζ-A), the extracellular splice variant (PTPζ-S) occurs as a major soluble chondroitin sulphate proteoglycan in the brain. We prepared antibodies which specifically recognize PTPζ-A and -S, and analysed the carbohydrate structures on the two PTPζ isoforms in the developing chick brain. lmmunoprecipitation experiments using these antibodies revealed that almost all of the keratan sulphate recognized by a monoclonal antibody (5D4) was exclusively bound to PTPζ-A and PTPζ-S. Addition of keratan sulphate to these proteoglycans markedly increased from embryonic day (E) 11, in contrast to the addition of Le^X and HNK-1 carbohydrates, which gradually increased during development in accordance with expression of the core proteins, suggesting that keratan sulphate modification plays some specific roles. Moreover, at the early embryonic stage keratan sulphate was observed only in several restricted regions, especially at boundary regions such as the roof plate of the tectum, the zona limitans intrathalamica in the diencephalon, and the mesencephalon-metencephalon boundary. At the mesencephalon-metencephalon boundary, keratan sulphate modification of PTPζ isoforms was specifically observed from E3 to E6 on a ring of cells encircling the neural tube and their radially oriented processes, which were identified as radial glial fibres. This expression pattern of keratan sulphate spatiotemporally corresponded well to the formation of the fovea isthmi, a groove separating the mesencephalon from the metencephalon. These results suggest that carbohydrates including keratan sulphate on PTPζ isoforms play important roles in brain development by modulating the cell-cell and/or cell-substrate interactions mediated by these molecules.