人血清载脂蛋白H的纯化与鉴定

为了研究载脂蛋白H（apoH)与疾病的关系，分别用HClO4,(NH4)2SO4沉淀、DEAE－纤维素离子交换层析，从人血清中纯化了载脂蛋白Ho用测定分子量，分析氨基酸组成和N－端氨基酸测序三个方面进行鉴定。用SDS－PAGE测得其相对分子量对54000。用高效液相色谱测定其中15种氨基酸的相对含量（mol/10^3mol残基）如下：Asp119.8,Glu108,Thr94.8,Ser78.6,Phe64.9,Gly1008,Ala57.2,Val57.2,Met10.6,Ile50.3,Leu77.1,Tyr31.9,His15.2,L-ys81.4,Arg39.4;d PE-ABI公司生产的475A型气相蛋白质测序仪上测得其N端10个氨基酸残基顺序如下：NH2－Gly-Arg-Cys-Pro-Asp-Asp-Leu。纯化得到的apoH与肝素有高的亲和性，还能与乙肝表面抗原结合。纯化apoH的方法相对比较简单，能达到测序的要求。     

广西三江县侗族青少年头发中9种元素的含量

目的　确定广西三江县侗族青少年头发中 9种人体必需元素含量的正常值。方法　用偏振塞曼原子吸收仪 ,检测了来自三江县的 993名 7～ 16岁中小学生头发中镍、硒、钴、铬、铁、锌、钙、铜和镁 9种人体必需元素的含量 ,并用SPSS统计软件进行统计分析。结果　广西三江县侗族中小学生头发中 ,镍、硒、钴、铬、铁、锌、钙、铜和镁 9种人体必需元素的含量没有性别差异 ;硒、铬、铁、锌、钙和铜与年龄呈负相关 ;制订了镍、硒、钴、铬、铁、锌、钙、铜、镁 9种元素的头发含量的正常值范围。结论　广西三江县中学生头发中硒、铬、铁、锌、钙和铜含量有明显年龄差异 ,而镍、钴和镁却没有年龄差异。     

Interferon-α activates cytotoxic function but inhibits interleukin-2-mediated proliferation and tumor necrosis factor-α secretion by immature human natural killer cells

Natural killer (NK) cells play an important role in host defense mechanisms against infection and neoplasia. Interferon- (IFN-) has been shown to activate NK cells and to augment their cytotoxic activity, albeit its role in the maturation pathway of NK cells has not been elucidated. The present study examined whether IFN- activates the immature NK subset (Free cells) to become cytotoxic and also ascertained whether IFN- uses the same pathway of activation as that mediated by interleukin-2 (IL-2). Incubation of sorted Free cells overnight with IFN- resulted in augmentation of their cytotoxic function against NK sensitive target cells. The enhanced cytotoxic activity was not accompanied by a new recruitment of NK-target binder cells but by an increase in the frequency of killer cells in the conjugate fraction. Activation of the Free subset by IFN- resulted in upregulation of CD69, CD11b, and CD2 surface expression and stimulated secretion of IFN-. Unlike IL-2, IFN- did not stimulate the Free cells to proliferate or secrete TNF- and activation of cytotoxicity and modulation of surface antigens by IFN- were independent of TNF-. The failure of IFN- to stimulate secretion and proliferation by Free cells appeared to be mediated by negative signals. This was corroborated in experiments demonstrating that when Free cells were cultured with both IFN- and IL-2, a significant inhibition was observed for both the IL-2 dependent secretion of TNF- and proliferation. These results demonstrate that IFN- serves as both an activator and a regulator of NK function. Further, activation of the immature Free NK cells by IL-2 and IFN- proceeds by TNF--dependent and independent pathways, respectively. The findings also support our contention that the mechanism of activation of the cytotoxic machinery of NK cells is not linked to the mechanism of activation of cytokine secretion and/or proliferation.Abbreviations used IFN interferon - IL interleukin - PBL peripheral blood leukocytes - PE phycoerythrin - PE-GAM PE-conjugated Fab2 goat anti-mouse IgG - NK natural killer - NRS normal rabbit serum - TNF tumor necrosis factor - FCS fetal calf serum - FITC fluorescein isothiocyanate - PBS phosphate-buffered saline - MACS magnetic cell sorting - ELISA enzyme-linked immunosorbent assay - BSA bovine serum albumin - PKC protein kinase C - mAb monoclonal antibody - PBMC peripheral blood mononuclear cells - BCLL B-chronic lymphocytic leukemia - E effector - T target     

Drug resistance in the fission yeast Schizosaccharomyces pombe: pleiotropic mutations affecting the oleic acid and sterol composition of cell membranes

Summary The whole cell lipid and sterol content of the drug resistant strains cyh1, cyh3 and cyh4 was compared with that of wild type by thin layer and gas liquid chromatography and by UV spectrophotometric analysis. The cyh3 and cyh4 strains had a decreased content of the unsaturated 18:1 fatty acid oleic acid, a decreased content of ergosterol and an increased content of 24,28 dehydroergosterol with respect to wild type. The cyh1 strain, however, only showed a decreased content of ergosterol and an increased content of 24,28 dehydro-ergosterol when compared to wild type.     

Outcome of renal transplantation following a positive cross-match with historical sera: the ASHI survey

Analysis of retrospective data, obtained on 216 patients from 27 centers transplanted across some form of positive lymphocyte cross-match in a noncurrent serum, revealed that actuarial 1-yr graft survival was 69% in first transplants and 53% in recipients of second or subsequent transplants. Graft outcome did not correlate with peak antibody levels, change in antibody from peak to current, remoteness in time of the most recent positive serum, the number or timing of sera cross-matched, the technique or target cell cross-matched, or the degree of positivity of the most recent positive serum. Although a concurrent control population was not available, these results support the concept that acceptable graft survival can be achieved despite a positive cross-match with noncurrent sera.     

Chromosomal changes in bovine papillomavirus type 1-induced Syrian hamster tumors

Bovine papillomavirus type 1 (BPV-1) induced fibrosarcomas in the Syrian hamster were studied cytogenetically by G- and C-banding techniques. All tumor derived cells showed chromosome abnormalities that remained stable during serial tumor transplantations. Cells without chromosome abnormalities found in two cultures were derived from the host animals on account of heterochromatin polymorphisms. In most tumors pseudodiploid cells prevailed, some cells were hypodiploid lacking one or two chromosomes, and one tumor showed two hyperdiploid cell clones with one and three additional chromosomes, respectively. Some of the chromosome abnormalities apparently are nonrandom. Three chromosomes (#1, #4, and #15) were most frequently involved in aberrations.     

Development of glomerular filtration rate and electrolyte and osmolal clearance in the late-embryonic and newly hatched chicken

Summary Techniques have been developed for collection of urine in embryonic and newly hatched chickens for the purpose of studying the development of renal function.The reliability of EDTA-⁵¹Cr as a substitute for inulin-¹⁴C in the determination of GFR was studied. Since inulin and EDTA-⁵¹Cr clearances in the hatched chicken averaged 1.61±0.23 (S.E.) ml/min per kg body weight and 1.58±0.27 ml/min per kg body weight, respectively, EDTA-⁵¹Cr clearance was considered a suitable measure of GFR.GFR increased significantly in the first few days after hatching. Filtration rate was 0.068±0.008 (S.E.) ml/min per g kidney weight in the embryo and increased to 0.148±0.008 ml/min per g shortly after hatching. By nine days after hatching GFR had risen to 0.290±0.015 ml/min per g, a value comparable to that reported for the adult.Clearances of sodium, potassium, chloride and total osmolyte also increased with age. When these clearances were corrected for changing glomerular filtration rates the embryonic chicks were found to excrete a greater percentage of the filtered load. These results show that adult levels of glomerulo-tubular balance are not attained until after hatching.A preliminary report of this work has already been published [3].     

Synthesis of polyetherurethanes containing L-serine dipeptide and their use as materials for biomedical films

Prepolymers, which were produced by the polyaddition reaction of polytetramethylene glycol (PTMG) or polyethylene glycol (PEG) and 4,4'-diphenylmethane diisocyanate (MDI) or hexamethylene diisocyanate (HMDI), were chain-extended with a linear dipeptide of L-serine (Z-Ser-Ser-OMe) or a cyclic dipeptide of L-serine [c-(Ser)2] to yield novel polyetherurethanes containing dipeptide segments. The relationship between the surface morphology and the biomedical properties of the film of the novel polyetherurethanes was investigated. The surface of PU(PTMG,Z-Ser-Ser-OMe,MDI) film was smooth, but fibrous structures were developed in the bulk of the film with increasing molecular weight of the PTMG segment. The antithrombogenicity of the film containing the low molecular weight PTMG segment was better than that of the usual polyetherurethane film without the dipeptide segments. The partial hydrolysis of the ester groups involved in the dipeptide segment improved the antithrombogenicity. In the surface and the bulk of PU[PTMG,c-(Ser)2,MDI] film, spherulite structures were developed when the molecular weight of the PTMG segment was high, while single crystals with a length of 3-4 microns were produced when the molecular weight of the PTMG segment was low. The antithrombogenicity of the film containing the high molecular weight PTMG segment was better than that of the usual polyetherurethane film without the dipeptide segments. PU(PTMG/PEG,Z-Ser-Ser-OMe,MDI) film and PU[PTMG/PEG,c-(Ser)2,MDI] film were permeated by uraemic toxins. The permeation was accelerated with increasing water content of the film and decreasing molecular weight of the solute. The oxygen permeability of the film of the polyetherurethane containing the linear or cyclic dipeptide segments was greater than that of polyetherurethane film which does not contain the dipeptide segments.     

Effect of bronchodilator therapy administered by canister versus jet nebulizer

Bronchodilator efficacy of metaproterenol sulfate aerosol therapy delivered either by canister or jet nebulizer was compared in 25 patients, 13 with severe asthma and 12 with COPD. Treatment was carried out in double-blind crossover fashion on 2 days and consisted of either metaproterenol sulfate solution 15 mg in 2.3 ml administered from a jet nebulizer or three puffs of metered-dose metaproterenol sulfate (total 1.95 mg) inhaled sequentially. FVC and FEV1 were monitored before and after therapy for 2 hr. In 13 asthmatic patients, FEV1 increased from a baseline mean of 0.83 L to 1.57 L at 2 hr after jet nebulizer therapy and increased from 0.84 L to 1.52 L after canister therapy. In 12 patients with COPD, FEV1 increased from 0.58 L to 0.78 L after jet nebulizer therapy and from 0.57 L to 0.76 L after canister therapy. FVC also increased similarly after each form of therapy. The two types of aerosol therapy were equally effective and were without side effects. Canister therapy has the advantage over jet nebulizer therapy by being convenient and cheaper.