人体单臂间歇运动对发汗调定点的影响

本工作系在微小气候相对恒定条件下,对10名健康男青年每人进行四项实验。实验 Ⅰ 为测定双侧腿足浸入43℃水中,诱发左前臂屈侧显现定量汗点时的口腔温度(舌下)阈值,作为发汗调定点参考值(ToSSP);实验 Ⅱ 为 Ⅰ 附加右臂间歇轻负荷运动(77W)时测定 ToSSP,部分对象还记录了皮肤电反应;实验 Ⅲ、Ⅳ 为 Ⅰ、Ⅱ 均附加4.5m/s 气流(22—25℃)直吹头面部,再分别测定 ToSSP。实验 Ⅰ 与 Ⅱ 同体对照22人次,Ⅲ 与 Ⅳ 同体对照24人次。结果表明,实验 Ⅱ、Ⅳ 的 ToSSP 均值及其潜伏期均值分别较 Ⅰ、Ⅲ 者降低(P<0.01)或缩短(P<0.001);Ⅰ、Ⅱ间的 ToSSP 均值差、潜伏期均值差,分别与 Ⅲ、Ⅳ 之间者无显著差异(P>0.2);Ⅱ、Ⅳ 的ToSSP 均值各与其实验开始前的口温均值亦无明显差异(P>0.5)。此结果支持运动时体温调定点下降的论点,并提示在研究体温调定点活动时,以 ToSSP 为指标较用发汗速率为优越,因 ToSSP 不为许多干扰因素所影响。     

普通小麦栽培品种丰抗13的4B—1D染色体易位的鉴定

通过细胞学观察,在普通小麦栽培品种“丰抗13”和“京红1号”的杂交后代中,发现有多价体出现,这就表明有染色体易位发生。为进一步弄清究竟是哪条染色体发生了易位,我们采用单体测交方法,观察鉴定所有各单体系F_1的花粉母细胞第一次减数分裂中期Ⅰ(以下简称PMCs中Ⅰ)染色体构型。从鉴定结果发现,凡2n=42的F_1 PMCs中Ⅰ出现19~Ⅱ 1~Ⅳ,而2n=41的F_1PMCs中Ⅰ的染色体构型不同,单体与易位有关的两个单体系4B和1D F_1 PMCs中的Ⅰ构型中有部分呈现为19个二价体加1个三价体,即19~Ⅱ 1~Ⅲ,没有单价体,而其余各单体系F_1 PMCs中Ⅰ构型则表现为18个二价体,1个四价体和1个单价体,即18~Ⅱ 1~Ⅰ 1~Ⅳ。因此,可以肯定“丰抗13”存在1个染色体易位,其有关染色体就是4B和1D。     

Diffusivity of oxygen into carriers entrapping whole cells

The effective diffusivity of oxygen, D(e), in Ca-alginate and PVA-SbQ gels was measured using a two-chamber vessel with a membrane between the two chambers. The effect of cell density, C(c), on D(e) in Ca-alginate gels was studied. The effective diffusivity of oxygen decreased with increasing cell density, to C(c) = 170 kg dry cells/m(3) gel. The dependency of D(e) on cell density was discussed in terms of a random-pore model. The model correlated well with experimental data, i.e., kD(e)/D(0) = 0.86(1 - 1.47 x 10(-3) C(c))(2). Here, k is the partition coefficient, and D(0) is diffusivity in water.     

Genetic Analysis of Olfactory Behavior in Drosophila: A New Screen Yields the Ota Mutants

A simple means of measuring Drosophila olfactory response is described, and the behavior which it measures is characterized. The assay was used to screen for X-linked mutants defective in olfactory function. Six ota mutants were isolated and characterized (ota = olfactory trap abnormal). Four of the mutants were found to be abnormal in another chemosensory behavior as well. Two of the mutant phenotypes extend to include another sensory system: they are defective in visual system physiology. All were normal, however, in a test of giant fiber system physiology. Two of the mutations are dominant, and the recessive mutations define two complementation groups. Mutations representing each complementation group, as well as one of the dominant mutations, were mapped. For the mutants with defective visual system physiology, the visual defects were shown to cosegregate with olfactory phenotypes.     

Purification and kinetic properties of lysophosphatidylinositol acyltransferase from bovine heart muscle microsomes and comparison with lysophosphatidylcholine acyltransferase

The enzyme acyl-CoA:1-acyl-sn-glycero-3-phosphoinositol acyltransferase (LPI acyltransferase, EC 2.3.1.23) was purified approximately 11,000-fold to near homogeneity from bovine heart muscle microsomes. The purification was effected by extraction with the detergent 3-((3-cholamidopropyl)dimethylammonio)-1-propanesulfonate, followed by chromatography on Cibacron blue agarose, DEAE-cellulose, and Matrex gel green A. The isolated enzyme was a single protein of 58,000 Da as measured by polyacrylamide gel electrophoresis in the presence of dodecyl sulfate. This purification procedure also allows isolation of the related enzyme lysophosphatidylcholine (LPC) acyltransferase, which was separated from LPI acyltransferase at the final chromatographic step. The purified LPI acyltransferase exhibits an absolute specificity for LPI as the acyl acceptor. Broader specificity was found for acyl-CoA derivatives as substrates, although the preferred substrates are long-chain, unsaturated derivatives: measured reactivities were in the order arachidonoyl-CoA greater than oleoyl-CoA greater than eicosadienoyl-CoA greater than linoleoyl-CoA. Little activity was found with palmitoyl-CoA or stearoyl-CoA as potential substrates. These properties are consistent with a role of the enzyme in controlling the acyl group composition of phosphoinositides. Comparison of LPC acyltransferase and LPI acyltransferase shows that these two enzymes have distinct kinetic and physical properties and are affected differently by local anesthetics, which are potent inhibitors.     

A review of the in vitro and in vivo neurochemical characterization of the NMDA/PCP/Glycine/Ion channel receptor macrocomplex

Conclusions Current neurochemical studies of the NMDA receptor macromolecular complex are yielding new insights into the interactions of the subunits of this complex and the associated potential clinical benefits of selective modulation of these subnits. Such studies offer the great potential for a new generation of pharmacotherapies for a wide range of CNS disorders, including stroke, a condition for which there is currently no effective pharmacological treatment. However, it is essential to understand that the first generation products in this area may not be optimal pharmacotherapies, such that haracterization of possible receptor subtypes and understanding the molecular biology of the component proteins of the receptor complex will be crucial in the design of the optimal pharmacological modulators of the NMDA receptor complex.Special issue dedicated to Dr. Erminio Costa     

血管平滑肌细胞的钙动力学

血管平滑肌细胞外的Ca~(2+)通过多种通道进入细胞内。Ca~(2+)通道的本质是镶嵌在膜脂质双分子层中的糖蛋白,神经介质和药物可影响Ca~(2+)通道的功能。靠近胞膜的肌质网和胞膜内侧面的高亲和性Ca~(2+)结合位点是血管平滑肌细胞内储存和释放Ca~(2+)的主要部位。胞浆[Ca~(2+)]增高后在钙调蛋白的介导下引起血管收缩。高血压等血管性疾病的发生与其平滑肌细胞的钙动力学异常有关。