体外培养人牙髓细胞的生物学特征

为研究牙髓细胞的生物学特性 ,采用组织块原代培养方法体外培养人牙髓组织。原代培养组织块在接种后 7～ 1 0d开始长出细胞 ,培养约 30d ,细胞形成单层汇合后进行传代培养。传代至第 5代测定细胞生物学特征及来源。结果 :培养人牙髓细胞呈成纤维样 ,抗波形丝蛋白染色阳性 ;细胞内碱性磷酸酶 (ALP)阳性 ,细胞内ALP总活性随培养天数的增加逐渐增高 ;细胞Ⅰ型胶原、FN染色阳性 ;第 5代细胞培养至第 1 1天发现细胞生长成结节状 ,分泌网形胶原样物质 ,在其表面出现结晶样钙化小点 ,经VonKossa染色 ,呈阳性。实验证明 ,体外培养的人牙髓细胞为来源中胚层的成纤维样细胞 ,可分泌ALP、Ⅰ型胶原及FN ,在体外可发生矿化 ,是深入探讨牙髓生理及矿化机制的良好的实验材料     

单态氧猝灭剂叠氮钠治疗角膜碱烧伤实验研究

为研究叠氮钠对角膜碱烧伤的治疗作用,在家兔的角膜碱烧伤模型中,用1 g/L NaN3及10 g/L NaN3+100g/L枸橼酸钠滴眼剂治疗.同时用硫代巴比妥酸(TBA)反应法检测过氧化脂质(LPO),用组织培养人角膜上皮细胞检测NaN3毒性,发现角膜烧伤后LPO逐渐减少.治疗组病情较轻,且NaN3毒性低,认为角膜碱烧伤后,用NaN3治疗有一定效果.     

国产洋红霉素对P388细胞单链DNA断裂及核仁超微结构的影响

用碱洗脱技术观察了国产洋红霉素（ＤＭＮ）引起小鼠淋巴白血病Ｐ３８８细胞单链ＤＮＡ的断裂作用。在ＣＭＮ０．２５－２．０μｇ／ｍｌ范围内,这种作用是剂量依赖性的。电镜观察研究ＣＭＮ对Ｐ３８８细胞核仁超微结构的影响。ＣＭＮ１．０μｇ／ｍｌ作用２小时,核仁空泡增多、微球体出现;作用４小时,核仁仁空增多、微球体出现;作用４小时,核仁“帽”形成;作用８小时,部分细胞核仁成分碎裂。     

基因工程耐热碱性磷酸酯酶的表达与分离纯化

目的　获得可用于探针的非放射性标记的耐热碱性磷酸酯酶。方法　把耐热碱性磷酸酯酶的基因克隆入质粒pJLA5 0 3上 ,在E .coliMph44中表达。表达的酶用聚乙烯亚胺沉淀核酸 ,热变性 ,硫酸铵沉淀 ,层析等方法纯化。结果　经表达纯化后每克细菌可获得 1.5mg的酶 ,酶的纯度为 90 % ,比活为 78.4U/mg。结论　耐热碱性磷酸酯酶可在E .coliMph44中表达 ,表达的酶可用热变性和其它蛋白质纯化方法来纯化。     

尿中某些酶测定在丁胺卡那肾毒性监测中的应用

探讨药物致肾损伤早期诊断方法。用酶法测定碱性磷酸酶（ＡＬＰ）。速率法测γ－谷氨酰转肽酶（ＧＧＴ）,Ｎ－乙酰－β－Ｄ氨基葡萄糖苷酶（ＮＡＧ）、β－半乳糖苷酶（Ｇａｌ）及肌肝（ＵＣｒ）,磺柳酸法测尿蛋白（Ｐｒｏ）。结果：尿酶升高均早于尿蛋白的出现,特别是ＮＡＧ于用药后第３天即有显著升高,Ｇａｌ则在用药后３ｄ内持续升高,尿酶,特别是ＮＡＧ是药物引起肾损伤早期诊断指标。     

重组人骨形态发生蛋白-2/7融合基因的构建及其在大肠杆菌中的表达和初步活性测定

构建重组人骨形态发生蛋白－２／７融合体, 研究其在大肠杆菌中的表达及生物学活性。利用ＤＮＡ 重组技术,将编码人骨形态发生蛋白－２ （ＢＭＰ－２） 成熟肽的０．３６ ｋｂ 基因片段与编码人骨形态发生蛋白－７ （ＢＭＰ－７） 成熟肽的０．４４ｋｂ 基因片段连接,得到重组人骨形态发生蛋白－２／７ 融合基因; 经测序鉴定后,将其克隆到表达载体ｐＢＶ２２２中,转化大肠杆菌ＤＨ５α, 温度诱导表达。表达蛋白经初步纯化后测定其对培养小鼠成骨样细胞增殖、分化及碱性磷酸酶活性的影响。克隆质粒转化的工程菌,经４２℃诱导４～６ ｈ 后,高效表达重组人骨形态发生蛋白－２／７, 在ＳＤＳ－ＰＡＧＥ上出现一新的蛋白带, 分子量约２９ ｋｕ,约占菌体总蛋白的２０％ ,表达蛋白以包涵体的形式存在,经初步纯化、裂解、复性后的ＢＭＰ－２／７ 蛋白具有促进成骨样细胞分化、增殖及增加碱性磷酸酶活性的作用。ＢＭＰ－２／７ 融合基因的构建和表达,可能提供一种全新的具有诱导成骨作用的蛋白     

某些酶活性变化对评价生长发育期大鼠锌营养的意义

雄性断乳大鼠随机分为低锌组、高锌组、正常锌组和低锌组的高锌饲料对饲组。喂相应饲料２０天后,低锌组的部分大鼠改喂高锌饲料（低 高锌组）,高锌组的部分大鼠改喂低锌饲料（高 低锌组）。分别于实验期０、２０、５０和７０天时处死。测定血浆碱性磷酸酶、５′ 核苷酸酶和铜 锌型超氧化物歧化酶活性、血浆锌及肾脏锌含量变化,以考核它们对评价锌营养状况的意义。结果表明：碱性磷酸酶、５′ 核苷酸酶以及血浆锌浓度变化对缺锌或／和补锌反应敏感。短期缺锌时（２０天）碱性磷酸酶活性就显著降低,并随缺锌时间延长该酶活性持续降低,而短期补锌（３０天）后又能显著增加其活性。受锌营养状况影响,血浆５′ 核苷酸酶活性也有类似的变化趋势。但这些酶活性又受增龄因素的影响,即随实验期增加,正常锌组碱性磷酸酶活性呈降低趋势,而５′ 核苷酸酶活性则呈增加趋势。长期严重缺锌可以影响铜 锌型超氧化物歧化酶活性;补锌后在实验期内未见到它的活性显著增加。随实验期增加,低锌组血浆锌持续降低,５０天时,显著低于高锌组;７０天时,低锌组和高 低锌组的血浆锌也显著低于高锌和低 高锌组。这些结果提示,碱性磷酸酶和５′ 核苷酸酶的活性及血浆锌变化对评价大鼠锌营养状况有一定的意?     

Figures of merit to compare distributed linear inverse solutions

Summary This paper introduces the concept of the resolution matrix as the basis for an objective theoretical comparison of distributed linear inverse solutions to the neuroelectromagnetic inverse problem. In particular, we describe how figures of merit derived from the resolution matrices can be represented graphically to evaluate merits and shortcomings of the different solutions. The use of the figures of merit is illustrated with two solutions that consider minimal a priori information about the generators: Classical Minimum Norm and Backus Gilbert. We recommend to start any analysis with the individual exploration of the resolution kernel for each grid point or at least for those points where the activity is likely to occur. This analysis might help in selecting the optimal inverse for the sources that are supposed to be active in the process under study.This work was supported by a grant from the Deutsche Forschungsgemeinschaft (Klinische Forschergruppe Biomagnetismus and Biosignalanalyse). Partial support was received from Swiss National Foundation grant 4038-044081/1.     

Biophysical studies and anti‐growth activities of a peptide,a certain analog and a fragment peptide derived from α‐fetoprotein

Abstract: A chemically synthesized 34‐amino acid peptide, an analog, and a fragment of the peptide have been purified and studied. Biophysical studies were carried out to determine some of the metal ion binding properties of the original peptide and an analog of this parent peptide, in which the two histidine residues were replaced by alanines. As shown by visible absorption spectroscopy, Co (II) forms a complex with the parent peptide, but not with the analog peptide, and one or two histidines in the parent peptide are ligands for Co (II) ion binding. The effects on disulfide bond formation in the peptide by Zn (II) and Co (II) ions were also examined for this analog. Anti‐growth assays were performed using the original cysteine‐containing peptide with Zn (II) ion complexed to the peptide through the two cysteine residues. These rat uterine growth assays showed that the complexing of Zn (II) ion to the peptide maintained the anti‐growth activity of the peptide, while gel‐filtration experiments showed the zinc ions maintained the peptide in its anti‐growth form indefinitely in solution. A saliently important part of this research was the discovery that a fragment of the peptide consisting of a middle sequence of 14 amino acids was found to have significant anti‐growth activity in the rat uterine assay. Its activity suggested that this fragment might be considered a viable candidate for testing in anti‐cancer protocols.     

Genetic analysis of hypophosphatasia

A review is presented of the recent advances in: (i) clinical features, (ii) biochemistry and molecular biology of alkaline phosphatase, (iii) genetic defect in hypophosphatasia, and (iv) prenatal diagnosis. Despite the recent progress, the pathogenesis of hypophosphatasia is far from being elucidated. More clinical cases and further characterization of the alkaline phosphatase gene mutations are needed for better understanding of the clinical spectrum of the entity.