Inhibition of glutamate release in rat hippocampus by kynurenic acid does not protect CA1 cells from forebrain ischemia

We assessed the effect of a broad spectrum glutamatergic receptor antagonist, kynurenic acid (500 mg/kg) on ischemia-induced hippocampal glutamate release and neuronal damage. Kynurenic acid significantly decreased glutamate release during ischemia but had no effect on the hippocampal lesion. Some protection was observed in the cortex and in the striatum. These data suggested that the extracellular accumulation of glutamate during forebrain ischemia does not play a major role in the hippocampus.     

Cloning and expression of SLC1OA4,a putative organic anion transport protein

AIM:To determine if novel bile acid transporters may be expressed in human tissues.METHODS:SLC10A1 (NTCP) was used as a probe to search the NCBI database for homology to previously uncharacterized ESTs. The homology search identified an EST (termed SLC10A4) that shares sequence identity with SLC10A1 and SLC10A2 (ASBT). We performed Northern blot analysis and RT-PCR to determine the tissue distribution of SLC10A4. SLC10A4 was cloned in frame with an epitope tag and overexpressed in CHO cells to determine cellular localization and functional analysis of bile acid uptake.RESULTS:Northern analysis revealed that SLC 10A4 mRNA is ubiquitously expressed fn human tissues with the highest levels of mRNA expression in brain,placenta, and liver. In SLC10A4-transfected CHO cells,immunoblotting analysis and immunofluorescence staining demonstrated a 49-kDa protein that is expressed at the plasma membrane and intracellular compartments.Functional analysis of SLC10A4 showed no significant taurocholate uptake in the presence of sodium when compared to untransfected CHO cells.CONCLUSION:To date, we have shown that this protein has no capacity to transport taurocholate relative to SLC1041; however, given its ubiquitous tissue distribution, it may play a more active role in transporting other endogenous organic anions.     

Developmental changes of glutamate acid decarboxylase 67 in mouse brain after hypoxia ischemia

Objective To study the developmental changes of glutamic acid decarboxylase-67 (GAD-67, a GABA synthetic enzyme) in normal and hypoxic ischemic (HI) brain. Methods C57/BL6 mice on postnatal day (P) 5, 9, 21 and 60, corresponding developmentally to premature, term, juvenile and adult human brain were investigated by using both Western blot and immunohistochemistry methods either in normal condition or after hypoxic ischemic insult. Results The immunoreactivity of GAD67 was up regulated with brain development and significant difference was seen between mature (P21, P60) and immature (P5, P9) brain. GAD67 immunoreactivity decreased in the ipsilateral hemisphere in all the ages after hypoxia ischemia (HI) insult, but, significant decrease was only seen in the immature brain. Double labeling of GAD67 and cell death marker, TUNEL, in the cortex at 8h post-HI in the P9 mice showed that (15.6±7.0)% TUNEL positive cells were GAD67 positive which was higher than that of P60 mice. Conclusion These data suggest that GABAergic neurons in immature brain were more vulnerable to HI insult than that of mature brain.     

接枝环氧树脂水分散液的合成、分离与表征

控制不同的反应条件,采用甲基丙烯酸、苯乙烯与环氧树脂在丙二醇丁醚/正丁醇溶剂中接枝共聚,合成了粒径在87～104nm范围的环氧树脂水分散液。通过环己烷/乙醇和丙酮两步萃取,对接枝共聚产物进行分离,用FTIR表征,并估算了接枝共聚物的组成。实验结果表明,所制备的粒径为纳米级的环氧树脂水分散液,具有良好的机械稳定性、冻融稳定性及贮存稳定性。ξ电位测定表明,产物在pH>8的条件下更为稳定。     

全反式维甲酸治疗急性早幼粒细胞白血病期间D-二聚体测定的临床意义

目的　探讨在全反式维甲酸 (ATRA)治疗急性早幼粒细胞白血病 (APL)前后弥漫性血管内凝血(DIC)发生率与D 二聚体含量的关系及意义。方法　应用ELISA法检测 30例APL患者 (包括 12例合并DIC患者 )发病时及应用ATRA治疗后D 二聚体水平的变化 ,并与正常对照组比较。结果　 30例APL患者治疗前血浆D 二聚体水平 (2 .38± 0 .98mg/L)较正常对照组 (0 .2 5± 0 .0 9mg/L)明显升高 (P <0 .0 1) ,其中 12例并发DIC者(2 .5 2± 0 .12mg/L)明显高于 18例不并发DIC者 (2 .18± 0 .96mg/L)。结论　APL患者D 二聚体检测值随维甲酸治疗逐渐降低 ,并可预测ATRA治疗过程中DIC变化及预后。     

血浆抗凝物质及花生四烯酸代谢产物在高脂血症患者的临床意义

目的:研究血浆抗凝物质及花生四烯酸代谢产物在高脂血症患者的临床意义。方法:临床诊断的高脂血症患者与正常对照组进行比较,其中抗凝血酶 Ⅲ抗原(AT- Ⅲ:Ag)、α1 抗胰蛋白酶(α1 - AT)和α2 巨球蛋白(α2 - MG)采用免疫浊度法;抗凝血酶Ⅲ活性(AT -Ⅲ:A)用发色底物法;血栓烷B2 (TXB2 )和6 - 酮前列腺素F1α(6 - K PGF1α)用放射免疫法。结果:患者组AT Ⅲ:Ag与正常对照组比较无差异(P >0 .0 5 ) ,但AT Ⅲ:A与正常组比较降低,α1 - AT无差异,α2 - MG有显著意义增高(P <0 .0 5 ) ,患者组TXB2 与正常组比较明显增高而6- K PGF1α明显降低(P <0 .0 1 )。结论:抗凝指标降低(AT- Ⅲ:A)示高凝状态,TXB2 和6 - K PGF1α的改变是高脂血症患者的危险因素,对于患者病理意义的研究是有帮助的,也显示患者极易发生动脉硬化的原因。     

Role of the cell recognition molecule, cognin, in GABAergic differentiation in chick retina

Previous work showed that GABAergic differentiation in developing chick retina depends on insulin and cell interactions. Here, we investigated whether it depended on cell signaling mediated by retina cognin, a 50 kDa cell recognition molecule. Cognin mediates cell adhesion in vitro and occurs on retinal neurons that become both GABAergic and cholinergic. We investigated two markers of GABAergic differentiation: glutamate decarboxylase (GAD) activity and high-affinity GABA uptake. Both increase during differentiation of retinal neurons in culture and can be easily measured. We blocked cognin-mediated cell signaling with cognin antibody and found a reduction of the developmental increase in GAD activity in cultures of retinal neurons from 7 and 11 day chick embryos. There was no reduction of high-affinity GABA uptake. This suggested that cognin-mediated signaling was necessary for the normal developmental increase in GAD but not for high-affinity GABA uptake. These results contrasted with our previous observations on cholinergic differentiation in cultured retinal neurons. We found that cognin antibody blocked the normal developmental increase in choline acetyltransferase (ChAT) only if the cells were exposed before embryonic day 7. Thus, while both GAD and ChAT activity appear to be controlled by cell signaling involving cognin, the periods of developmental sensitivity for the two differentiation markers are different. Antibodies to other adhesion molecules, Ng-CAM, and N-cadherin, did not similarly affect GAD activity. Antibodies to laminin at a 10-fold higher concentration inhibited GAD activity only in early embryonic retina. Tests for protein synthesis and “housekeeping” enzyme activity demonstrated that the cognin antibody effect was selective for neuronal differentiation pathways. Thus, GABAergic differentiation in developing retina is sensitive to cell signaling mediated in part by cognin.     

Effects of immobilization stress on hippocampal monoamine release: Modification by mivazerol, a new α2-adrenoceptor agonist

Mivazerol is a new and selective α₂-adrenoceptor agonist which has demonstrated anti-ischemic effects, both in animals and in patients with myocardial ischemia. In the present study, mivazerol was evaluated for its ability to inhibit the release of catecholamines and serotonin (5-HT) in the hippocampus of freely moving rats, and also was compared to clonidine. In vivo microdialysis in combination with high-performance liquid chromatography (HPLC) was employed. Intravenous administration of mivazerol (8.0 μg/kg) had no effect on basal outflow of norepinephrine (NE), dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC). In contrast, clonidine (8.5 μg/kg, i.v.) attenuated the basal release of DOPAC, which has been proposed to reflect NE biosynthesis, suggesting that clonidine has an inhibitory effect on NE synthesis. In addition, both mivazerol and clonidine decreased the spontaneous release of 5-HT, which provided further evidence that α₂-adrenoceptors in the hippocampus modulate 5-HT. Sixty-min immobilization stress significantly increased the release of NE (177 ± 28%), DA (209 ± 46%) and DOPAC (337 ± 72%). Mivazerol (2.5, 8.0 and 25 μg/kg, i.v.) completely prevented the immobilization stress-induced enhancement of NE, DA and DOPAC, which was equi-effective to clonidine at a dose of 8.5 gmg/kg, i.v. These findings demonstrate that mivazerol has a profound modulatory effect on stress-induced neurotransmitter release in the hippocampus, at dose levels reported to protect against myocardial ischemia.     

乳酸氧化酶分离纯化的研究

粪链球菌发酵液经菌体破壁、丙酮分级沉淀、硫酸铵盐析、DEAE-纤维素柱色谱,Sephadex G-150分子筛和 Sephadex A-50柱色谱等分离步骤,制得较纯的乳酸氧化酶,可用于酶盒测定。     

茶碱和双丁酰-cAMP对巨噬细胞水解酶影响的细胞化学观察

本文通过细胞体外培养,细胞化学定量分析等方法,观察了茶碱和双丁酰-cAMP对C_(57)BL/6J小鼠腹腔巨噬细胞酸性磷酸酶、α-醋酸萘酚酯酶的作用和影响.卡介苗活化的巨噬细胞与固有巨噬细胞相比,其酸性磷酸酶、α-醋酸萘酚酯酶活性明显升高.卡介苗活化的巨噬细胞在茶碱或双丁酰-cAMP作用下。酸性磷酸酶、α-醋酸萘酚酯酶活性明显受到抑制.茶碱或双丁酰-cAMP对固有巨噬细胞的酸性磷酸酶、α-醋酸萘酚酯酶无抑制作用.