神经肽DGAVP和Org2766对神经细胞内游离Ca2+的影响

运用Ca²⁺指示剂Fura-2作为细胞内钙离子的荧光探针,利用AR—CM—MIC阳离子测定系统,检测了分离的神经细胞内游离钙及其变化,并观测了DGAVP和Org2766对蛋白质合成抑制剂茴香霉素(ANI)引起细胞内钙离子浓度([Ca²⁺]_i)变化的影响。结果表明茴香霉素可使[Ca²⁺]_i显著升高,且有量效关系;DGAVP本身并不引起[Ca²⁺]_i发生显著变化,但适当剂量的DGAVP可显著对抗一定剂量范围内ANI升高[Ca²⁺]_i的作用,提示DGAVP对抗ANI的蛋白质合成抑制效应可能是通过拮抗ANI升高[Ca²⁺]_i这一途径实现的,另一神经肽Org2766则可能不是通过这一机制发生作用。从细胞内Ca²⁺的角度看,这两种肽的作用机理显然是不同的。     

Neonatal treatment with 192 IgG-saporin produces long-term forebrain cholinergic deficits and reduces dendritic branching and spine density of neocortical pyramidal neurons

The role of basal forebrain-derived cholinergic afferents in the development of neocortex was studied in postnatal rats. Newborn rat pups received intraventricular injections of 192 IgG-saporin. Following survival periods ranging from 2 days to 6 months, the brains were processed to document the cholinergic lesion and to examine morphological consequences. Immunocytochemistry for choline acetyltransferase (ChAT) and in situ hybridization for ChAT mRNA demonstrate a loss of approximately 75% of the cholinergic neurons in the medial septum and nucleus of the diagonal band of Broca in the basal forebrain. In situ hybridization for glutamic acid decarboxylase mRNA reveals no loss of basal forebrain GABAergic neurons. Acetylcholinesterase histochemistry demonstrates a marked reduction of the cholinergic axons in neocortex. Cholinergic axons are reduced throughout the cortical layers; this reduction is more marked in medial than in lateral cortical areas. The thickness of neocortex is reduced by approximately 10%. Retrograde labeling of layer V cortico-collicular pyramidal cells reveals a reduction in cell body size and also a reduction in numbers of branches of apical dendrites. Spine densities on apical dendrites are reduced by approximately 20-25% in 192 IgG- saporin-treated cases; no change was detected in number of spines on basal dendrites. These results indicate a developmental or maintenance role for cholinergic afferents to cerebral cortical neurons.      

双胸蚯蚓溶栓酶对沙鼠缺血额叶皮质超微结构及离子的影响

采用结扎沙土鼠双颈总动脉20分钟后恢复血流制做脑缺血再灌注模型。应用透射电镜对额叶皮质超微结构进行观察,并采用电镜能谱技术对神经元随机检测Na~十Ca~卄等离子含量。结果表明,缺血的对照组神经元Na~十明显增高达16.43,而缺血后腹腔注入双胸蚯蚓溶栓酶的实验组显著下降为13.02,接近正常组的11.47;Ca~卄正常组为1.03,对照组增高达3.81,而实验组下降为2.44。同时实验组超微结构的损伤性改变明显轻于对照组。     

The effect of different calcium antagonists and a calcium agonist on the metabolism of propranolol by isolated rat hepatocytes

Summary— The influence of the dihydropyridine calcium entry blockers nicardipine, amlodipine, nifedipine, isradipine and of the dihydropyridine calcium entry promotor BAY K 8644 on the disappearance rate of propranolol by isolated rat hepatocytes was compared to the effect of diltiazem and verapamil, two non-dihydropyridine calcium channel blockers and known inhibitors of hepatic cytochrome P450 mixed function oxidases. All compounds dose-dependently inhibited the disappearance rate of propranolol. Nicardipine and isradipine were more potent in inhibiting the disappearance rate of propranolol than the other dihydropyridines and than diltiazem and verapamil. The inhibitory effect of nicardipine on the disappearance rate of propranolol was not stereoselective and was not influenced by age.     

Aggregated IgE mimic interleukin-3-induced histamine synthesis by murine hematopoietic progenitors

Similar to interleukin-3 (IL-3), IgE acts on murine bone marrow cells by inducing histamine production. This effect does not result from degranulation of histamine-containing cells, but from histamine synthesis, as assessed by the following findings. (1) The histamine content of freshly isolated bone marrow cells is too low to account for the increase in extracellular histamine levels. (2) Neither IL-3 nor IgE induced histamine production in the presence of the specific inhibitor of histidine decarboxylase (HDC), the histamine-forming enzyme. (3) Both the enzymatic activity and the mRNA expression of HDC were enhanced in response to IL-3 or IgE. Artificial aggregation or formation of IgE immune complexes augmented ther effect on histamine synthesis, indicating that the aggregated form is responsible for this biologic activity. Yet, it is apparently not mediated by Fc epsilon RI because their cross-linkage by dinitrophenyl bovine serum albumin after presensitization with IgE did not induce histamine production by hematopoietic progenitors. Among other aggregated isotypes tested, only IgG2a and, to a lesser extent, IgG1 had a consistent but lower effect, whereas IgM and IgA were completely inactive. The target cells of IL-3 and IgE in terms of histamine synthesis do not belong to mature bone marrow populations, especially mast cells. They copurify with hematopoietic progenitors in the low-density layers of a discontinuous Ficoll gradient where they represent around 5% of the cells, as determined by in situ hybridization. This percentage remained the same, regardless of whether the cells were stimulated by IgE or IL-3 alone or by a combination of both, suggesting a common responder cell. In accordance with this notion, histamine-producing cells could not be distinguished from each other on the basis of density, size and internal structure, or rhodamine (Rh) retention. Finally, the effect of IgE is not caused by the induction of IL-3 because anti-IL-3 antibodies did not abrogate the effect of IgE.     

基于受体结构的药物分子设计系统:维甲类分子与其结合蛋白之间相互作用的研究

大分子解剖程序,配体分子契合适配和DOCK程序,以及计算化学的其它程序等,已集成为基于受体结构和分子间相互作用的进行分子设计的软件系统,定名为BIOS(Biomolecularinteractionsandorientationsimulator)。BIOS软件可在普通的微机上运行。使用BIOS分别剥离了细胞浆维甲结合蛋白(CRBP)和副睾维甲酸结合蛋白(E-RABP)两种蛋白的配体结合腔,剥离是围绕配体以同样的分子距离进行的。从而得到了芳香性残基分布相似的两个结合腔,其结合位点的几何排布却有相当差别。揭示出的结合腔已用于一系列的维甲类化合物的DOCK研究。E-RABP的结合腔可做为设计新维甲类分子的模板。     

Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11

In a large collaborative screening project, 370 men with idiopathic azoospermia or severe oligozoospermia were analysed for deletions of 76 DNA loci in Yq11. In 12 individuals, we observed de novo microdeletions involving several DNA loci, while an additional patient had an inherited deletion. They were mapped to three different subregions in Yq11. One subregion coincides to the AZF region defined recently in distal Yq11. The second and third subregion were mapped proximal to it, in proximal and middle Yq11, respectively. The different deletions observed were not overlapping but the extension of the deleted Y DNA in each subregion was similar in each patient analysed. In testis tissue sections, disruption of spermatogenesis was shown to be at the same phase when the microdeletion occurred in the same Yq11 subregion but at a different phase when the microdeletion occurred in a different Yq11 subregion. Therefore, we propose the presence of not one but three spermatogenesis loci in Yq11 and that each locus is active during a different phase of male germ cell development. As the most severe phenotype after deletion of each locus is azoospermia, we designated them as: AZFa, AZFb and AZFc. Their probable phase of function in human spermatogenesis and candidate genes involved will be discussed.      

Photic driving in migraine: correlations with clinical features

Fifty-eight migraineurs were. studied by intermediate frequency steady-state visual evoked potentials (SSVEPs) during headache-free periods. Sex, age, age of onset of migraine, duration of illness, type of migraine, side of pain, sleep .wake disorders, and frequency of migraine attacks did not correlate with any SSVEP abnormalities. On the other hand, visual responsiveness was significantly increased in subjects with family history of migraine, and in those with autonomic symptoms. Our results may indicate that a genetic predisposition to migraine underlies the observed abnormal visual response in migraineurs.