Inhibition of glucose transport in human erythrocytes by 2,3-dioxoindole (Isatin)

10 mM isatin (2,3-dioxoindole) inhibited glucose influx into human erythrocytes by over 30%. The inhibition is of the competitive type, where the affinity constant (K_t) was increased from 5.71 (control) to 11.11 mM in the presence of isatin with no change in V_max (130 nmol/min/ml packed cells). The observed inhibition of sugar transport by isatin was not mediated through membrane–SH groups accessible to iodoacetate, iodoacetamide, DTNB, DNP or sodium arsenite. Isatin inhibited sugar transport in the presence of 2 mM harmaline, an alkaloid inhibitor of Na⁺, K⁺–ATP_ase activity. The inhibition was non additive which suggests that these two compounds interact with the same or a similar site on the erythrocyte membrane.     

Role of hsp70 in cytokine production

Interleukin-1 and tumor necrosis factor-alpha are potent, multifunctional cytokine mediators of inflammation and immune responses that are produced primarily by activated monocytes and macrophages. Three published papers by different groups have shown that heat shock and chemical stress with heavy metal salts or sulfhydryl reagents, all of which induce the expression of heat shock protein 70 (hsp70), concomitantly inhibit the production of these cytokines in human monocytes and mouse macrophages activated by lipopolysaccharide. These papers are reviewed and discussed in some detail. Other studies suggest that various anti-inflammatory drugs, including acetylsalicyclic acid, auranofin and dexamethasone, can also facilitate HSP expression in macrophages. However, while these studies are interesting, it is clear that not a great deal of work has been done and/or published in this area. Since many pharmaceutical companies are developing cytokine synthesis inhibitors as potential anti-inflammatory drugs, one aim of this article is to emphasize that understanding the molecular mechanism(s) that lead to increased HSP expression and decreased cytokine biosynthesis may assist in achieving this goal.     

模型校正在电子设备结构中的应用

为预测构件动态行为，用动力学有限元校正法建立某一航天用印刷电路板的动力学模型，用物理参数局部校正法导出物理意义明确的校正模型，用分步实验校正法提高模型的可靠度。结果表明，校正模型具有更大的适应性和可靠性。     

五峰垃圾填埋场渗滤液污染特征及处理系统

系统分析了五峰垃圾填埋场渗滤液中ＣＯＤ，ＢＯＤ＿５的季节变化特征，并对该填埋场的污水处理系统进行了研究和评价。     

Nb对Li／MgO甲烷氧化偶联催化剂的助催化作用

Ｌｉ／ＭｇＯ甲烷氧化偶联催化剂引入铌的氧化物可降低活性温度，７５０℃以下便达到最高Ｃ２烃产率。铌与锂、镁有多种结合方式，引入方法对活性测试结果有重要影响。铌不与镁紧密结合且分布于锂、镁之间时作用最好。     

Calcium/calmodulin-dependent protein kinase II increases glutamate and noradrenaline release from synaptosomes

A variety of evidence indicates that calcium-dependent protein phosphorylation modulates the release of neurotransmitter from nerve terminals. For instance, the injection of rat calcium/calmodulin-dependent protein kinase II (Ca2+/CaM-dependent PK II) into the preterminal digit of the squid giant synapse leads to an increase in the release of a so-far unidentified neurotransmitter induced by presynaptic depolarization. But until now, it has not been demonstrated that Ca2+/CaM-dependent PK II can also regulate neurotransmitter release in the vertebrate nervous system. Here we report that the introduction of Ca2+/CaM-dependent PK II, autoactivated by thiophosphorylation, into rat brain synaptosomes (isolated nerve terminals) increases the initial rate of induced release of two neurotransmitters, glutamate and noradrenaline. We also show that introduction of a selective peptidergic inhibitor of Ca2+/CaM-dependent PK II inhibits the initial rate of induced glutamate release. These results support the hypothesis that activation of Ca2+/CaM-dependent PK II in the nerve terminal removes a constraint on neurotransmitter release.     

Sex determination compared in Drosophila and Caenorhabditis

Fruitflies and nematodes show many similarities in the general organization of the gene networks that control sexual dimorphism and dosage compensation. In contrast, the underlying molecular mechanisms appear to be very different in these two species. Developmental processes such as sex determination need not be strongly conserved in evolution.     

A binding site for the T-cell co-receptor CD8 on the alpha 3 domain of HLA-A2

Adhesion measurements between CD8 and 48 point mutants of HLA-A2.1 show that the CD8 alpha-chain binds to the alpha 3 domain of HLA-A2.1. Three clusters of alpha 3 residues contribute to the binding, with an exposed, negatively charged loop (residues 223-229) playing a dominant role. CD8 binding correlates with cytotoxic T-cell recognition and sensitivity to inhibition by anti-CD8 antibodies. Impaired alloreactive T-cell recognition of an HLA-A2.1 mutant with reduced affinity for CD8 is not restored by functional CD8 binding sites on an antigenically irrelevant class I molecule. Therefore, complexes of CD8 and the T-cell receptor bound to the same class I major histocompatibility complex molecule seem to be necessary for T-cell activation.