蘑菇多糖对小鼠腹腔巨噬细胞作用的体外研究

目的 观察蘑菇多糖对小鼠腹腔巨噬细胞免疫调节作用及对体外培养的肿瘤细胞作用的影响。方法 采用比色法测定经蘑菇多糖处理的巨噬细胞内LDH的活性。MTT法观察蘑菇多糖与巨噬细胞的共同培养上清对HL-60细胞及K562细胞的抑制率。结果 （1）蘑菇多糖明显激活小鼠腹腔巨噬细胞的共同培养上清对HL-60细胞及K562细胞的抑制率。结果 （1）蘑菇多糖明显激活小鼠腹腔巨噬细胞，显著提高巨噬细胞的LDH活性；（2）蘑菇多糖作用下的巨噬细胞上清液可显著抑制HL-60细胞及K562细胞的增殖。结论 蘑菇多糖的抗肿瘤作用可能是通过激活小鼠腹腔巨噬细胞的活性实现的。     

Investigation of the anti-complement agents, FUT-175 and K76COOH, in discordant xenotransplantation

Abstract: We examined whether hyperacute rejection (HAR) of a discordant xenograft in a nonhuman primate model could be inhibited by the anticomplement agents, FUT-175 (FUT) and K76COOH (K76). The inhibitory effect of FUT and K76 on baboon sera was studied in vitro by i) complement-mediated hemolysis of sheep erythrocytes (by measuring serum CH50) and ii) cytotoxicity to cultured pig kidney (PK15) cells. The in vivo administration of FUT (at 0.2–25 mg/kg/h i.v. continuously) and K76 (50 mg/kg i.v. bolus) allowed evaluation of the serum levels of these drugs. Both FUT and K76 inhibited serum CH50 in a concentration-dependent manner. An enhanced effect was obtained by combining K76 with FUT therapy. High concentrations of FUT (>10^-4 M) and K76 (>10³ μxg/ml) were necessary to suppress serum CH50 to <5% of the normal level. However, PK15 cytotoxicity remained at >50% in the presence of i) 10^-4 M of FUT, ii) 10³ μg/ml of K76, and iii) 10^-6 M of FUT + 10³ μg/ml of K76. Pig heart transplantation (HTX) was performed in two baboons receiving FUT (1 mg/kg/h i.v. continuously) and K76 (at 200 mg/kg ×1 or 400 mg/kg + 200 mg/kg × 2 i.v, respectively). Cytotoxicity of the serum to PK15 cells at the time of HTX showed 39% and 1% cell death, respectively, in these two baboons, and the CH50 level was 1% (of control level) and 0%, respectively. Graft survival was 4.5 hours and 10 hours (with death of the baboon), respectively (compared with a mean of 29 minutes in control experiments). Both excised grafts showed typical features of hyperacute rejection. Immunopathological studies revealed deposition of C1q, C3d, C6, properdin, and Factor B, demonstrating that complement activation was not fully inhibited by FUT and K76. We conclude that i) FUT and K76 are indeed potent complement inhibitors, ii) the dosages of FUT and K76 necessary to suppress complement-mediated injury cannot be extrapolated from previously reported data obtained from serum CH50 levels, and iii) higher (possibly toxic) dosages will be required to inhibit complement activation completely. It seems unlikely that HAR will be prevented by these drugs alone, although they may be beneficial when combined with other forms of therapy.     

Selective sensitivity of synaptosomal membrane function to cerebral cortical hypoxia in newborn piglets

The effect of hypoxia on the structure and function of the synaptosomal membranes and myelin fraction (glial cells, neuronal cell bodies and axonal membranes) was investigated by measuring Na⁺,K⁺-ATPase activity and levels of lipid peroxidation products in cerebral cortical synaptosomal membranes and myelin fractions obtained from newborn piglets. Hypoxic hypoxia was induced and cerebral hypoxia was documented as a decrease in the ratio of phosphocreatine to inorganic phosphate (PCr/Oi) using³¹P-NMR spectroscopy. PCr/Pi decreased from baseline of2.93 ± 0.76to0.61 ± 0.36 during hypoxia. The synaptosomal membrane Na⁺,K⁺-ATPase activity decreased from a control value of56.6 ± 3.7to40.4 ± 6.0 μgmol Pi/mg protein/h during hypoxia. The level of conjugated dienes increased from zero (reference value) to4.5 ± 2.7 nmol/mg lipid and the level of fluorescent compounds increased from23.5 ± 2.2to92.6 ± 46.4 ng quinine sulfate/mg lipid in the synaptosomal membranes during hypoxia. No change in myelin fraction Na⁺,K⁺-ATPase activity or levels of lipid peroxidation products were noted. These data indicate that sunaptosomal membranes, rich in polyunsaturated fatty acids, are more susceptible to oxygen free radical mediated lipid peroxidative damage during hypoxia.     

The role of Na+/K+ ATPase activity during low flow ischemia in preventing myocardial injury: A 31P, 23Na and 87Rb NMR spectroscopic study

An increase in intracellular Na⁺ during ischaemia has been associated with myocardial injury. In this study, we determined whether inhibition of Na⁺/K⁺ ATPase activity contributes to this increase and whether Na⁺/K⁺ ATPase activity can be maintained by provision of glucose to perfused rat hearts during low flow, 0.5 ml/min, ischemia. We used ³¹P NMR spectroscopy to determine changes in myocardial energetics and intracellular and extracellular volumes. ²³Na NMR spectroscopy, with DyTTHA^3- present as a shift reagent, was used to measure changes in intracellular Na⁺ and ⁸⁷Rb NMR spectroscopy was used to estimate Na⁺/K⁺ ATPase activity from Rb⁺ influx rates, Rb⁺ being an NMR-sensitive congener of K⁺. In hearts provided with 11 mM glucose throughout ischemia, glycolysis continued and ATP was twofold higher than in hearts without glucose. In the glucose-hearts, Rb⁺ influx rate was threefold higher, intracellular Na⁺ was fivefold lower at the end of ischemia and functional recovery during reperfusion was twofold higher. We propose that continuation of glycolysis throughout low flow ischemia allowed maintenance of sufficient Na⁺/K⁺ ATPase activity to prevent the increase in intracellular Na⁺ that would otherwise have led to myocardial injury.     

内皮超极化因子的研究进展

内皮超极化因子（EDHF）是由内皮释放的NO和PGI_2以外的另一种舒张因子,它通过使平滑肌细胞膜超极化而舒张血管,是内皮依赖性血管松驰的第3种重要机制。EDHF可能是花生四烯酸的细胞色素P450代谢产物EET-s,乙酰胆碱、缓激肽等激动剂作用于内皮细胞,使细胞内游离钙浓度升高,合成和（或）释放EDHF,作用于平滑肌细胞膜,激活钙依赖性钾通道,使细胞膜超极化,抑制电压依赖性钙通道的开放,引起血管松弛。在大血管中NO-cGMP松弛机制可能占主导地位,并且抑制EDHF生成;而在阻力小血管,EDHF则可能是引起血管松弛的主要因素。     

The Drosophila Mutant tetanic Interacts with a Gene Complex Including the Structural Locus of K+ Channels and Shows Altered Dephosphorylation and Learning

The tetanic (tta; X.-52.6) mutation has been isolated on the basis of its sensitivity to extradoses of the normal Shaker gene complex (ShC) where the K+ channel la is encoded. The mutant shows up to threefold elevation of the membrane bound protein phosphatase type 1 (PP1) activity in body extracts, probably due to reduced levels of the PP1 specific inhibitor 2 (I-2). By contrast, PP1 activity in the head is only half of the normal value. In addition, tta fails to perform normally in a negative reinforcement olfactory paradigm. The functional relationships between phosphorylation, K+ currents, phosphatase activity and modulation of synaptic activity during learning and memory are discussed in the light of their possible genetic links.     

新生儿G6PD缺陷病和晚发性维生素K缺乏症的特点与预防

目的 探讨新生儿C6PD缺陷病和晚发性维生素K缺乏症的危害与预防措施。方法 回顾分析1995-2000年儿内科住院的1周-2月(不含2月)的婴儿3104例次，其中病死56例。结果 1周-2月的小婴儿占住院患儿的19．34％，其中新生儿G6PD缺陷病239例，占7．70％；晚发性维生素K缺乏症92例，占2．96％。死因的第2、3位分别是晚发性维生素K缺乏症(13例，占23．21％)和新生儿C6PD缺陷病(12例，占21．43％)，两者的病死率分别为14．13％和5．02％，极显著高于(x^2＝17．59，P＜0．01)或相近于(x^2＝0．88，P＞0．05)肺炎的3．57％。新生儿G6PD缺陷病合并感染占38．49％、低氧血症占23．35％、低血糖占19．25％、酸中毒占15．90％，继发胆红素脑病占13．81％。晚发性维生素K缺乏症出现抽搐占90．22％、胃肠、注射部位出血占60．89％；CT证实颅内出血占98．91％。结论 1周-2月的小婴儿约占住院患儿的两成，新生儿G6PD缺陷病和晚发性维生素K缺乏症的病死率均很高，两者是除肺炎外最主要的死因。提议制定并推广预防这2种疾病的常规措施，并参照国内外相应的现状拟出其具体内容。     

Alteration of acylphosphatase levels in familial Alzheimer''s disease fibroblasts with presenilin gene mutations

Acylphosphatase (ATPase), an enzyme that modulates the activity of Ca²⁺-ATPase by hydrolysing its phosphorylated moiety, has been found to be significantly higher in cultured skin fibroblasts from donors affected by early onset familial Alzheimer's disease (EOFAD) with PS-1 and PS-2 gene mutations. Of the two known isoenzymes of acylphosphatase, only the erythrocyte one accounts for the total increase in activity. No relevant alteration was observed in phosphotyrosine phosphatase activity (PTPase), in Ca²⁺-ATPase and Na⁺,K⁺-ATPase activities of the same cells as compared to age-matched controls. This finding could suggest a possible explanation for the calcium-dependent biochemical alterations previously described in Alzheimer's disease fibroblasts.     

Natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) activities can be differentiated by their different sensitivities to interferon and prostaglandin E1

Though purported to be identical cells (or in identical populations of cells), the natural killer (NK) cell mediating spontaneous natural cytotoxicity and the killer (K) cell mediating antibody-dependent cellular cytotoxicity (ADCC) may not be totally identical, at least in susceptibility to regulation by the immunomodulators prostaglandin E₁ (PGE₁) and interferon (IFN). We demonstrate here that NK cells are always enhanced by IFN, while K cells are inhibited from binding targets, resulting in fewer effectors at optimal concentrations of antibody. Only at 10- to 100-fold suboptimal concentrations of antibody is ADCC activity enhanced. As measured by magnitude of inhibition and dose-response titration, ADCC activity is less sensitive to the effects of PGE₁ than is NK activity in the⁵¹Cr release assay and single-cell assay. After overnight incubation with or without PGE₁, whatever sensitivity ADCC activity had to PGE₁ is lost. However, NK cells incubated in the presence of PGE₁ overnight are still sensitive to inhibition. Indomethacin boosts NK activity without having any effect on ADCC activity. Finally, NK activity is substantially reduced by overnight incubation of cells at room temperature, which has no effect on K cells.