软骨血管生成抑制因子抑制血管生成的研究

小牛气管软骨经盐酸胍抽提,丙酮分级沉淀,膜超滤,柱层析等步骤得到软骨血管生成抑制因子(cartilage angiogenesis inhibiting factor,CAIF).SDS-聚丙烯酰胺凝胶电泳显示CAIF由单一组分组成,分子量为27700.通过[ ³H]-TdR掺入,活细胞检测等方法测定CAIF对内皮细胞、Hela细胞、QGY7703细胞与小鼠骨髓细胞、人皮肤成纤维细胞等的DNA合成的影响,以及细胞毒作用.采用鸡胚绒毛尿囊膜实验测定CAIF对血管生成的抑制效应.结果显示:CAIF对内皮细胞产生强的抑制作用,对Hela细胞抑制很弱,对QGY7703细胞、小鼠骨髓细胞、人皮肤成纤维细胞均无抑制作用;对鸡胚绒毛尿囊膜的血管生成产生明显的抑制作用.提示CAIF能较特异地抑制血管生成,CAIF达到电泳纯,是专一性较强的血管生成抑制因子.     

显微红外研究巨噬细胞膜电融合后膜蛋白二级结构的变化

首次尝试了将显微傅里叶变换红外光谱术应用于研究电融合后细胞膜蛋白质二级结构的变化,发现脉冲电场作用于细胞具有穿透效应,施加电脉冲后,整个细胞的蛋白质体系能量增加,表明电泳冲对蛋白的二结构影响很大;同时,还发现用唾液酸苷酶和蛋白酶Ｐｒｏｎａｓｅ分析处理巨噬细胞膜表面后,膜上蛋白质二级结构无序化程度增加,用酶适度处理的细胞将更易发生电融合。     

Culture of chondrocytes in medium supplemented with fetal calf serum or a serum substitute: Ultroser G

Fetal calf serum and a serum substitute, Ultroser G, were compared for their effects on the growth curves, clonal growth and cell cycle progression of rabbit chondrocytes in primary culture and during at least three cell passages and included a screen for the maintenance of cartilage-like differentiation i.e. the presence of type II collagen. Proliferation was also compared with another serum substitute, Nu-Serum. Ultroser G is shown to be equivalent to fetal calf serum as far as chondrocyte proliferation is concerned, clonal growth is improved and biosynthesis of type II collagen is maintained in primary culture.     

Studies on regulation of chorionic gonadotropin secretion in primates

The regulation of secretion of chorionic gonadotropin in primates has been studied using bothin vivo andin vitro models.In vivo studies using the pregnant bonnet monkey revealed that at the doses tested, the administration of progesterone or estradiol 17Β in combination or alone did not result in any appreciable change in the duration or magnitude of serum chorionic gonadotropin levels. However, administration of lutropin-releasing hormone by intravenous route resulted in significant increase in chorionic gonadotropin levels within 30–60 min and the extent of stimulation seemed to depend on the state of pregnancy. Forin vitro studies, explants or cells prepared from first trimester human placenta has been used. The functional integrity of these cells has been established by demonstrating the binding of [¹²⁵I]-labelled human chorionic gonadotropin antibody to the cells as well as the synthesis of [³H]-labelled human chorionic gonadotropin.In vitro studies using the cells revealed that addition of lutropin-releasing hormone caused a significant increase in chorionic gonadotropin and estradiol 17Β secreted into the medium. Thus bothin vivo andin vitro results suggest that lutropin-releasing hormone could be one of the factors involved in regulation of chorionic gonadotropin secretion in primates.     

Post-coital agents and menses inducing drugs

The importance of developing of drugs which could be taken post-coitally or used once-a-month in the case of a delay in the onset of the menses is well recognized. The availability of such technology would limit exposure to fertility regulating agents to such occasions where there is coital exposure or possibility of pregnancy.Methods of post-coital contraception used so far include IUD’s inserted post-coitally, estrogens, and combinations of estrogens and gestagens. These are reserved primarily for emergency situations to protect women from unwanted pregnancy resulting from rape or unprotected coitus. Levonorgestrel has shown satisfactory results in terms of contraceptive efficacy and is being further evaluated clinically. A number of problems inherent in the development of post-coital contraception are discussed.Menstrual regulation could be achieved by a number of approaches: (a) block progesterone receptors and interfere with the preparation of the endometrium for implantation; (b) luteolysis leading to decreased progesterone levels and interruption of implantation; and (c) termination of early pregnancy by prostaglandins. A number of progesterone antagonists have been evaluated. One of the compounds, RU38486 is being evaluated clinically for termination of very early pregnancy.Deglycosylated derivatives of human chorionic gonadotropin have been shown to antagonize the action of human chorionic gonadotropin and interfere with established pregnancy in rats. Appropriate methods of delivery, immunogenicity and alternate methods for production of human chorionic gonadotropin need to be considered before evaluation of the derivatives for clinical use. In vitro and invivo models need to be developed for evaluation of the teratogenicity and embryotoxicity of post-coital and menses inducing agents.There are a number of gaps in the knowledge of the processes regulating implantation which should be investigated in rodents and in different non-human primate species.     

Pyrophosphate and fructose 2,6-bisphosphate effects on glycolysis in pea seed extracts

The participation of pyrophosphate-dependent phosphofructokinase (PPi-PFK) in plant glycolysis was examined using extracts from pea seeds (Pisum sativum L. cv Alaska). Glycolysis starting with fructose 6-phosphate was measured under aerobic conditions as the accumulation of pyruvate. Pyruvate accumulated in a medium containing PPi and adenosine diphosphate at about two-thirds of the rate in a medium containing adenosine diphosphate and adenosine triphosphate (ATP). The PPi-dependent pyruvate accumulation had the same reactant requirements and sensitivity to glycolysis inhibitors, sodium fluoride, and iodoacetamide, as the well-established ATP-dependent glycolysis. Added fructose 2,6-bisphosphate stimulated both the PPi-dependent pyruvate accumulation and PPi-PFK activity whereas this modulator had no effect on ATP-dependent glycolysis or ATP-PFK. Collectively these results demonstrate a PPi-dependent glycolytic pathway in plants which is responsive to fructose 2,6-bisphosphate.     

Effect of temperature and baroreceptor stimulation on reflex venomotor responses

To investigate the interaction of thermal reflexes and baroreflexes in the control of the peripheral veins, we studied in supine humans the effects of lower body negative pressure (LBNP) and neck suction (NS) on forearm veins at ambient temperatures (Ta) of 18, 28, and 37 degrees C. Forearm venous volume (FVV)-venous pressure (FVP) relations (forearm venous capacitance) on six subjects showed an increase from 18 through 28 to 37 degrees C (P less than 0.001). Heart rate increased (P less than 0.001) and forearm venous capacitance decreased (P less than 0.001) in proportion to the level of LBNP applied from 20 to 50 Torr at all Ta. At 50 Torr LBNP, FVV at 30 cmH2O, FVP decreased from control values of 2.5, 3.8, and 4.4 to 1.6, 2.7, and 3.4 ml/100 ml at 18, 28, and 37 degrees C, respectively. We also studied venomotor responses using the occluded limb technique. Although LBNP caused venoconstriction, NS applied either alone or during LBNP produced no change in venomotor tone. Therefore we concluded that carotid baroreceptors play little role in reflex venomotor adjustments. Since changes in mean arterial and pulse pressures during LBNP did not account for the observed venomotor responses, we concluded that low-pressure baroreceptors initiate significant venoconstrictor reflexes over a wide range of Ta.     

大豆根尖维管组织分化和静止中心

用~3H-胸腺嘧啶核苷标记的自显影方法测定了大豆根尖的静止中心。结果表明在萌发后24小时产生,其高度为最大值,随着天数增加静止中心的高度逐渐减小。静止中心的高度与根的直径显著相关(r=0.94,p=0.01)。用显微光度计测定了静止中心细胞核的DNA 含量,大部分细胞在2c 水平,处在 G_1期。大豆根尖的静止中心与维管组织分化水平不相关,静止中心不直接控制维管组织的分化。     

Immunocytochemical localization of basic protein in major dense line regions of central and peripheral myelin

To localize basic protein (BP) in the lamellar structure of central and peripheral myelin, we perfused newborn and 7-11-day rat pups with a phosphate-buffered fixative that contained 4% paraformaldehyde and 0.05 or 0.2% glutaraldehyde. Teased, longitudinally split or "brush" preparations of optic and trigeminal nerves were made by gently teasing apart groups of myelinated fibers with fine forceps or needles. Some of these preparations were immunostained without pretreatment in phosphate-buffered antiserum to BP according to the peroxidase-antiperoxidase method. Others were pretreated in ethanol before immunostaining. Then, all of them were dehydrated, embedded in Epon, and sectioned for electron microscopic study. In optic and trigeminal nerves that were not pretreated, myelin, glial cells, and their organelles were well preserved. BP immunostaining was present on cytoplasmic faces of oligodendroglial and Schwann cell membranes that formed mesaxons and loose myelin spirals. In compact central and peripheral myelin, reaction product was located in major dense line regions, and the myelin periodicity was the same as that observed in unstained control myelin that had been treated with preimmune serum. In ethanol-pretreated tissue, the myelin periodicity was reduced but dense line staining still was present. Our immunocytochemical demonstration of dense line localization of BP in both CNS and PNS myelin that was not disrupted or pretreated with solvents is important because of conflicting evidence in earlier immunostaining studies. Our results also support biochemical and histochemical evidence suggesting that BP exists in vivo as a membrane protein interacting with lipids on the cytoplasmic side of the bilayer in the spirally wrapped compact myelin membrane.