猪产仔数相关基因的研究进展

综述了与猪产仔数相关的基因：雌激素受体基因、卵泡刺激素β亚基基因、催乳素受体基因、视黄醇结合蛋白四基因等几种候选基因的研究进展；总结了产仔数的数量性状位点。     

超敏化学发光液稀释法降低蛋白印迹的发光强度

蛋白印迹(western blot)分析是根据抗原、抗体特异性结合的原理检测复杂样品中某蛋白的技术。然而当样品中的蛋白浓度过低,特别是目标蛋白为低丰度蛋白时,采用普通化学发光检测,有时出现蛋白条带发光弱,曝光不够,而采用超敏化学发光检测则出现蛋白条带发光强,曝光过度,两者的蛋白条带显影图像均不理想。本文将超敏化学发光液稀释后再检测,显影效果显著提高,蛋白条带图像清晰,可见超敏化学发光液稀释法降低蛋白印迹的发光强度,提高了蛋白条带的显影效果。     

多功能透明胶片

被列入国家“八五”重点科技攻关项目的多功能透明胶片日前在西北工业大学研制成功,并投入批量生产.该项研究成果已荣获国家发明银奖和航空航天部科技进步奖.多功能胶片用于微机排版系统.可省去现行胶片工艺的照相、显影、定影、冲洗、     

胶片潜影与显影

胶片感光乳剂层中的感光物质卤化银在受到光辐射后,产生光化学反应,卤化银微晶中的电子和离子发生交替独立的重复迁移,而形成显影中心,无数个显影中心,构成潜影。经显影剂的作用,还原成可见影象。     

显影条件对热敏微胶囊影像密度特性的影响

结合热敏技术、微胶囊技术,在制备出粒径1 μm以下热敏微胶囊基础上,测量了囊壁材料的玻璃化温度,对显影后的影像进行了对比.随显影温度提高、显影时间延长,影像密度呈现出先增大再逐渐达到稳定的变化趋势,分析了不同显影温度、显影时间条件对影像密度特性的影响,确定最佳显影温度为130 ℃,显影时间为5s.     

实验动物荧光素眼底血管造影影响因素的研究进展

荧光素眼底血管造影(FFA)可以精准直观的反应眼底相关病变，在眼底疾病动物模型的检测中不可或缺。FFA图片质量主要受显影强度和显影时间的影响，而显影强度和显影时间受诸多因素调控。笔者结合实验动物不同物种多年FFA拍摄经验并参考国内外研究文献，总结分析影响实验动物FFA显影强度和时间的各项可控因素，着重对比了实验动物不同物种与人类血液黏稠度、血液流速、血液pH值、体温的差别及对FFA显影强度及初次显影时间、维持时间、消退时间的影响。同时分析了对不同实验动物物种间FFA差异和FFA拍摄时引起动物不良反应的因素。希望提供这些信息和数据能够帮助解决研究者在实验动物FFA造影中遇到的问题，获得更准确可靠的检测结果，实现FFA检测在实验动物中的应用价值。     

胶片非线性特性对电子断层摄影术成像质量的影响

为了分析胶片的非线性特性对电子断层摄影术成像质量的影响,以Kodak4463(SO-163)型电子显微镜胶片为例,按照其成像光密度值与电子曝光量对数值之间的关系曲线(D-lgE曲线)对模型样品的线性投影像实施变换,并采用计算机仿真方法进行了三维重构.计算结果表明,随着最大曝光范围对应的D-lgE曲线片段的非线性度的增加,三维重构图像质量下降,尤其当最大曝光范围向D-lgE曲线的饱和区扩展时,三维重构的图像出现了严重失真的现象(重构图像与模型样品图像之间的相关系数从线性投影像对应的0.85减小到0.6以下).分析结果表明,调整样品的电子曝光量来改变胶片最大曝光范围在D-lgE曲线上的位置,可以降低胶片非线性特性对三维重构图像质量的影响,该研究结果对用胶片为记录媒体的电镜三维重构具有指导意义.     

PD感光胶片的研制及在缩微复印上的应用

PD照相法(即物理显影照相法)以其显著的特点在缩微技术上获得了重要的应用.PD感光胶片解相力很高,从而大大跨进了超缩微领域.它耗银极少,因而具有很高的经济价值.用PD感光胶片制作的缩微平片反差良好,图象清晰,耐磨耐潮,使用寿命长。研制工艺及其分析PD照相原理及一般步骤我们曾于另文叙述过.研制PD感光胶片选择了PD—D型反应,即是最初的光反应产物能使亚汞离子发生歧化反应而形成潜象核。PD感光胶     

独特的照相胶卷

最近,苏联研制成功了一种独特的热塑照相胶片。它能在没有银和传统的显影过程的情况下得到清晰的相片。科技人员把玻璃型半导体和热塑涂积在有弹性的片基上,并装上细而薄的金属电极。当还没有加上电压     

药物对小白鼠不同脑区GABA_A受体与外源性GABA_A结合的影响

用同位素示踪法测定药物对小鼠四个不同脑区的GABA_A受体与外源性GABA结合的影响。GABA_A受体颉颃剂Picrotoxin,bicuculline,青霉素,和GABA-T抑制剂AOAA均使大脑皮层的受体结合显著增加,中枢兴奋剂戊四唑使之显著地减少。AOAA使海马的受体结合显著增加,戊四唑及安定使之显著减少。蝎毒使下丘脑的受体结合显著增加,而戊四唑使之显著减少。AOAA、蝎毒、bicuculline、picrotoxin使小脑的受体结合显著增加。     

不同时期绿色荧光裸鼠雌鼠血浆及组织中性激素水平变化

目的 了解不同妊娠期、泌乳期绿色荧光(Green Fluorescence Protein,简称GFP)裸鼠雌鼠血浆中雌激素、孕激素、泌乳素及各组织中泌乳素及泌乳素受体mRNA水平变化。方法 通过电化学发光法测定血浆中激素的水平,通过荧光定量PCR法测定泌乳素及泌乳素受体mRNA相对表达量。结果 GFP裸鼠雌鼠妊娠期内雌激素和泌乳素水平不断下降、孕激素的水平先升后缓慢下降、组织中泌乳素mRNA水平较低、泌乳素受体水平较高;而在泌乳期内雌激素、孕激素水平较稳定、组织中泌乳素mRNA水平较高,泌乳素受体水平较低。结论 不同时期GFP裸鼠雌鼠体内性激素的水平不同,参与裸鼠妊娠调控过程,为解决雌鼠不孕、易流产等问题提供了基础参考值和内分泌水平的解决思路。     

A synthetic peptide that is a bombesin receptor antagonist

The tetradecapeptide bombesin was originally isolated from frog skin. Bombesin-like peptides have since been detected in mammalian gastrointestinal tract, brain and lung. These peptides have potent pharmacological effects on the central nervous system; they cause contraction of intestinal, uterine and urinary tract smooth muscle; and stimulate the release of other peptides including gastrin, cholecystokinin, motilin, pancreatic polypeptide, neurotensin, insulin, enteroglucagon, prolactin and growth hormone. Specific plasma membrane receptors for bombesin have been demonstrated on pancreatic acinar cells, brain membranes and pituitary cells. Studies defining the physiological importance of bombesin have been impeded by the lack of a bombesin receptor antagonist. Here we describe experiments which demonstrate that a peptide originally described as a substance P receptor antagonist, [D-Arg, D-Pro, D-Trp, Leu ]substance P, is also a bombesin receptor antagonist. This peptide competitively inhibits the ability of bombesin to stimulate enzyme secretion from dispersed pancreatic acini, and also inhibits the action of other peptides that interact with the bombesin receptor.     

中国美利奴羊PRLR基因外显子10SSCP多态性与部分繁殖性状的关联分析

以催乳素受体基因(PRLR)作为绵羊繁殖性状的候选基因,运用PCR-SSCP方法对PRLR外显子10的多态性进行检测,并对其多态性与绵羊部分繁殖性状进行了关联分析。结果表明:在PRLR外显子10的2个基因片段存在PCR-SSCP多态,PRLR1扩增片段存在3种基因型,PRLR2扩增片段存在4种基因型;Hardy-Weinberg平衡检验显示,中国美利奴羊群体在2个位点都处于平衡状态;CE和DD基因型中国美利奴羊产羔数均值比CD和DE型多0.31只(P<0.05);AA基因型中国美利奴羊初生重均值比BB型重0.66 kg(P<0.05);DE基因型中国美利奴羊3月龄重均值比CD型重2.42 kg(P<0.05)。     

Lactogenic receptor regulation in hormone-stimulated steroidogenic cells

Receptor sites for lactogenic hormones such as prolactin (PRL), human growth hormone (HGH), and placental lactogens, are widely distributed in mammalian tissues, including mammary glands, steroid-secreting cells of the adrenal, testis, and ovary, and target cells of steroid hormone action such as liver, prostrate, and kidney. Although the biological functions of lactogen binding sites remain uncertain, a relationship between prolactin and lipoprotein metabolism is implied by the occurrence of prolactin receptors in steroidogenic cells of the gonads and adrenal, and by the ability of prolactin to increase esterified cholesterol in the testis. Recently, loss of testicular prolactin receptors has been observed following elevation of circulating luteinising hormone (LH) concentrations by the gonadotropin releasing hormone (GnRH) and its agonist analogues. The hormone dependence of lactogen receptor sites in steroid-secreting cells was further analysed in rat testis, ovary, and adrenal glands after treatment with the respective trophic hormones, gonadotropin and ACTH. In each of these tissues, rapid and transient loss of lactogen receptors was observed after trophic hormone stimulation. These findings indicate that increased turnover of lactogen receptors is an important component of the target-cell response, and suggest that prolactin receptors might be involved in the transport of lipoprotein precursors for steroid biosynthesis.     

环亲和素A的重组表达及其促进肝癌细胞侵袭转移的体外研究

为研究环亲和素A（CyclophilinA,CyPA）与肝癌转移的关系,用原核重组表达并纯化了CyPA。在不同浓度的CyPA刺激下,利用凝胶酶谱检测人肝癌细胞FHCC-98分泌基质金属蛋白酶（matrix metalloproteinases,MMPs）的能力。选择合适的刺激浓度,用BordenChamber检测肝癌细胞的侵袭能力。同时用抗CD147的抗体阻断CypA与其受体CD147的结合,检测阻断后FHCC-98在CyPA刺激下分泌MMPs及转移的能力。结果表明重组表达的CyPA能促进FHCC-98分泌激活或非激活形式的MMP-2并能促进FHCC-98的转移,而抗CD147的抗体能阻断其作用。实验结果表明：环亲和素A能与肝癌细胞表面的受体分子CD147结合,促进肝癌细胞的转移,提示其在“炎-癌”链中起到一定的作用。     

兔抗人多发性骨髓瘤细胞多克隆抗体的制备与鉴定

制备人多发性骨髓瘤全细胞兔多克隆抗体。用人多发性骨髓瘤细胞系ARH-77全细胞和福氏完全佐剂通过背部皮内多点注射首次免疫新西兰大白兔,第14 d用ARH-77全细胞和福氏不完全佐剂同样剂量加强免疫,第28 d和38 d时再次免疫。第45 d颈动脉采血80 mL,4℃静置过夜,收集血清。然后采用亲和层析系统纯化血清中的多克隆抗体。用酶联免疫吸附试验(ELISA)检测纯化多克隆抗体的效价;免疫印迹法和荧光免疫细胞化学检测纯化多克隆抗体的特异性。结果:ELISA检测多克隆抗体滴度为1∶20 000,免疫印迹检测结果显示该抗体具有较高特异性,荧光免疫细胞化学检测多克隆抗体能够有效的结合细胞表面抗原。实验获得了高效价的特异性的兔抗人骨髓瘤细胞多克隆抗体,为进一步研究多发性骨髓瘤诊断和治疗奠定了基础。     

Influence of local vascularity on hormone receptors in mammary gland

Procedures, such as teat removal (thelectomy) or teat duct ligation, which prevent removal of milk, lead to rapid involution of the lactating mammary gland; performed unilaterally they have been used previously to study the biochemistry of involution, enabling a comparison of normal and involuting glands in the same animal against the same systematic hormonal environment. Both the protein hormone prolactin and the steroid hormone oestrogen are of importance in the development and function of the mammary gland. In the present experiments, female Sprague-Dawley rats were unilaterally thelectomised and the binding to the mammary gland of prolactin and oestrogen was examined through pregnancy, lactation and weaning. There was an effect of thelectomy during lactation only, when levels of both receptors increased in the intact lactating gland but failed to rise in the thelectomised, involuting gland. Capillary closure is known to occur in the mammary glands of rats after 36-48 h of milk accumulation. The rate of delivery of hormones to the tissue will be drastically reduced and it is concluded that this, rather than systemic hormone levels, is of importance in controlling receptor levels.     

Molecular cloning of cDNA encoding human interleukin-2 receptor

The human interleukin-2 (IL-2) receptor was purified by affinity chromatography using the anti-Tac monoclonal antibody, and its N-terminal amino acid sequence was determined. Complementary DNA clones were isolated and sequenced to reveal the primary structure of the IL-2 receptor precursor, which has 272 amino acid residues. The receptor is separated into two domains by a putative 19-residue transmembrane region. Two mRNAs (1.4 and 3.5 kilobases) hybridizing to the cDNA clone were found in human T cells bearing the IL-2 receptor. The cDNA directed synthesis of the IL-2 receptor in COS cells.     

Autoimmune diabetes as a consequence of locally produced interleukin-2.

During cell differentiation in the thymus, self-reactive T cells can be generated. The majority of these seem to be deleted after intrathymic encounter with the relevant autoantigen. As all self antigens are unlikely to be present in the thymus, some autoreactive T cells may escape censorship. Here we study the fate of these cells using transgenic mice expressing the class I molecule H-2Kb (Kb) in the insulin-producing beta-cells of the pancreas. These mice were crossed with mice transgenic for genes encoding a Kb-specific T-cell antigen receptor (TCR) which could be detected using a clonotype-specific monoclonal antibody. Although T cells expressing the highest level of transgenic TCR were deleted intrathymically in double-transgenic mice, Kb-specific T cells were detected in the periphery. These cells caused the rejection of Kb-expressing skin grafts, but ignored islet Kb antigens even after priming. But when double-transgenic mice were crossed with transgenic mice expressing the lymphokine interleukin-2 in the pancreatic beta-cells, there was a rapid onset of diabetes. These results indicate that autoreactive T cells that ignore self antigens may cause autoimmune diabetes when provided with exogenous 'help' in the form of interleukin-2.     

Localization of the binding site for the human high-affinity Fc receptor on IgG

A major pathway in the clearance of pathogens involves the coating of the pathogen with specific antibodies, and the binding of the antibody Fc region to cell receptors. This can trigger engulfment of the pathogen by phagocytes or lysis by killer cells. By oligonucleotide site-directed mutagenesis we have engineered a single amino acid change in a mouse IgG2b antibody (Glu 235----Leu) which now enables the antibody to bind to the FcRI (high affinity) receptor on human monocytes with a 100-fold improvement in affinity. This indicates that Leu 235 is a major determinant in the binding of antibody to FcRI and that the receptor may interact directly with the region linking the CH2 domain to the hinge. Tailoring the affinity of antibodies for cell receptors could help dissect their role in clearing pathogen.