硫化氢对体外大鼠肝星状细胞内Ca2+浓度变化及细胞增殖的影响

目的 研究硫化氢(H₂ S)对大鼠肝星状细胞-T6(HSC-T6) Ca²⁺浓度、细胞增殖的影响及其机制。 方法 活化HSC-T6用含10%小牛血清DMEM培养液制备为1×10⁵个肝星状细胞(HSC)悬液。钙离子荧光探针Fluo-3/AM负载细胞后，在不同刺激条件下，利用激光扫描共焦显微镜动态扫描HSC-T6细胞内Ca²⁺荧光强度（FI）变化，FI表示细胞内Ca²⁺浓度。四唑盐比色法，观察不同浓度H₂S供体——NaSH对HSC-T6细胞增殖的影响。 结果 低浓度H₂S（100μmol/L）明显降低HSC-T6细胞内Ca²⁺浓度（P<0.05)，而细胞增殖增加（增殖率为116%）；K_ATP通道阻断剂——格列本脲可阻断H2S的作用。高浓度H₂S（1mmol/L）刺激HSC-T6细胞内Ca₂₊浓度增加，但细胞增殖无明显变化(P＞0.05)。 结论 低浓度H₂S通过激活HSC-T6细胞K_ATP通道降低细胞内Ca²⁺浓度，可能通过调节细胞氧化应激促进细胞增殖；高浓度H2S刺激HSC-T6细胞内Ca₂₊浓度增加。提示H₂S在肝硬化门脉高压症的发生机制中具有双重作用。     

普罗布考抗过氧化氢诱导大鼠血管平滑肌细胞凋亡的初步研究

目的研究抗氧化剂普罗布考对过氧化氢(H2O2)诱导大鼠血管平滑肌细胞(VSMC)凋亡的影响.方法采用流式细胞术、高效液相色谱分析等方法研究不同浓度H2O2作用下细胞内还原型谷胱甘肽(GSH)含量变化与细胞凋亡,以及普罗布考抗凋亡作用与细胞内GSH变化的关系.结果①2mmol/LH2O2使细胞内GSHc含量下降至0.67μmol/L(P<0.01)、细胞凋亡率显著增加(45.70%).②普罗布考加H2O22rnmol/L共同处理后细胞内GSHc含量明显增加(3.53μmol/L),细胞凋亡率显著下降(21.59%).结论2mmol/L H2O2使细胞内GSHc含量显著下降,VSMC大量凋亡.普罗布考通过维持细胞内氧化还原平衡,降低细胞内GSH消耗,抑制H2O2诱导VSMC凋亡.     

应用基因表达谱芯片研究硫化砷作用后K562细胞基因表达的变化

目的：利用基因表达谱芯片检测K562细胞在硫化砷作用前后基因表达的差异性进行比较研究。方法：研究对象为人慢性粒细胞白血病细胞株K562,用cy3和cy5两种不同的荧光染料通过逆转录反应将K562经硫化砷作用前后的mRNA分别标记成两种探针,并与载有一组靶的基因表达谱芯片进行杂交,通过计算机扫描分析得到这些基因在经硫化处理前后的表达差异,结果：筛选出包括与DNA结合,转录和转录因子,蛋白翻译,细胞周期等相关表达差异的基因共11条,其中7条表达上调,4条表达下调,结论：周期素E2,周期素G2可能参与硫化砷诱导K562细胞凋亡发生机制。     

Effect of erythromycin on the oro-caecal transit time in man

Summary Erythromycins often cause gastrointestinal side-effects due to an increase in motility or to change in the intestinal bacterial flora. In order to evaluate the effect of erythromycin on gastrointestinal motility, 11 healthy volunteers were given placebo, erythromycin stearate (ES) 1000 mg or a therapeutically equivalent single dose of erythromycin acistrate (EA, 2-acetyl erythromycin stearate) 800 mg in a double-blind trial. The orocaecal transit time was measured using the hydrogen breath test with lactulose as the substrate. The transit time was estimated from the H₂-peak (ppm) in end-expiratory breath by two methods, t₁ representing the front and t₂ the bulk of lactulose reaching the colon.t₁ was 51 min in the placebo group, 38 min in the EA and 31 min in the ES group (p < 0.05, ES vs placebo). t₂ was 74 min, 64 min, and 46 min, respectively (p < 0.05, ES vs placebo). The difference between EA and ES was also significant. Six subjects in the ES group but none in the EA group recorded adverse gastrointestinal effects attributable to medication.It was concluded that erythromycin shortens the orocaecal transit time in man and that EA affects the transit time slightly less than ES.     

EDTA-NaOH吸收液--分光光度法测定空气中硫化氢的研究

本文对EDTA -NaOH作为硫化氢吸收液进行探讨和研究。试验表明 :当空气中硫化氢含量为国家最高允许液度 0 .6～ 6倍时 ,吸收液采样效率为 98.2～ 10 0 % ,催化剂与显色剂混合使用 ,可降低空白值 ,提高方法灵敏度。本法准确度 ( p)为 93 .0 % ,精密度合并变异系数 (cv)为 3 .93 % ;检出限、测量限分别为 7× 10 -2 μg/5ml和1.7× 10 -1μg/5ml;规定采气量为 0 .5L时 ,则最小检出浓度为 0 .6 8mg/m3。     

Hydrogen peroxide-induced impairment of reactivity in rat isolated aorta: potentiation by 3-amino-1,2,4-triazole

1. In this study the impairment induced by hydrogen peroxide of vascular reactivity and the role of endogenous catalase in protection against this impairment was assessed in isolated rings of rat aorta.
2. Incubation with hydrogen peroxide at 1 mM, but not at 0.1 mM, for 15, 30 or 60 min followed by washout depressed, in a time-dependent manner, the subsequent ability of endothelium-containing and endothelium-denuded rings to contract to phenylephrine.
3. Incubation with 3-amino-1,2,4-triazole (50 mM, 90 min, followed by washout) to inhibit endogenous catalase had no effect by itself on subsequent phenylephrine-induced contraction. However, pretreatment with 3-amino-1,2,4-triazole did lead to a profound enhancement of the ability of hydrogen peroxide (1 mM, present for the final 30 min of the 90 min incubation, followed by washout) to depress phenylephrine-induced contraction in both endothelium-containing and endothelium-denuded rings.
4. Incubation with hydrogen peroxide at 1 mM, but not at 0.1 mM, for 15, 30 or 60 min followed by washout inhibited, in a time-dependent manner, the subsequent ability of acetylcholine (10 nM–3 μM) to induce endothelium-dependent relaxation. Furthermore, incubation with hydrogen peroxide 1 mM (30 min, followed by washout) also inhibited relaxation induced by glyceryl trinitrate (1–100 nM) or isoprenaline (10 nM–3 μM) in endothelium-denuded rings.
5. Incubation with 3-amino-1,2,4-triazole (50 mM, 90 min, followed by washout) had no effect by itself on relaxation induced by acetylcholine, glyceryl trinitrate or isoprenaline. In contrast, pretreatment with 3-amino-1,2,4-triazole led to profound enhancement of the ability of hydrogen peroxide (1 mM, present for final 30 min of the 90 min incubation) to block relaxation to acetylcholine, glyceryl trinitrate or isoprenaline.
6. On the basis of the actions of 3-amino-1,2,4-triazole, it is likely that endogenous catalase plays an important role in the protection of vascular reactivity of rat aorta against oxidant damage by high (1 mM) but not lower (0.1 mM) concentrations of hydrogen peroxide. The data are consistent with the promotion of non-selective damage to the vascular smooth muscle cells by hydrogen peroxide, but endothelial damage may also be sustained.

     

Cumulative biochemical effects of repeated subclinical hydrogen sulfide intoxication in mouse brain

Summary Adult female NMRI mice exposed four times to 100 ppm hydrogen sulfide vapour for 2 h at 4-day intervals showed increasing inhibition of the cerebral cytochrome oxidase activity. Cerebral RNA decreased significantly after the fourth exposure. This change was accompanied by the reduced orotic acid uptake in the RNA fraction. At the same time, 2,3-cyclic nucleotide 3-phosphohydrolase activity used as a marker for glia increased. Acetylcholine esterase activity remained unchanged. The initial exposures also caused an increase in the superoxide dismutase activity and an increase in the glutathione concentration. The latter effects were abolished in the third and fourth exposures. The present data seem to indicate that the biochemical effects of repeated subclinical hydrogen sulfide intoxications are cumulative.     

不同浓度乙醇对内皮细胞分泌作用的影响

目的 研究不同浓度乙醇对内皮细胞的保护作用。方法 应用过氧化氢损伤培养的人脐静脉内皮细胞,并与不同浓度乙醇进行孵育,检测内皮细胞产生的内皮素及一氧化氮。结果低、中浓度乙醇明显减少损伤的内皮细胞产生的内皮素。同时实验还提示长时间高浓度乙醇对内皮细胞有明显损伤作用;不同浓度的乙醇均抑制内皮细胞产生一氧化氮。结论低、中浓度乙醇使内皮细胞在受损时生成的内皮素明显减少。     

过氧化氢对豚鼠耳蜗功能及形态的影响

目的 在体观察过氧化氢(H2O2)对豚鼠耳蜗功能及形态的影响。方法 实验动物分为4组，分别灌流人工外淋巴液(artificial perilymph,APL)，50μMH2O2，100μMH2O2和200μMH2O2(H2O2均溶于APL中)，并用Pl和H033342双染色方法观察H2O2引起的内耳细胞损伤情况。结果 所有H2O2灌流组复合动作电位((CAP)阈移和耳蜗微音电位(CM)幅度变化与人工外淋巴液组比较差异有显著性，且各H2O2组的变化呈现出浓度依赖性；Pl和H033342双染色方法发现外毛细胞是H2O2攻击的主要靶细胞，而Hensen细胞未见任何损伤痕迹。结论 H2O2可导致耳蜗功能下降及耳蜗毛细胞损伤：Hensen细胞较毛细胞可能具有更强的抗氧化能力。     

N,N-二甲胺基硫代乙酰胺的合成研究

目的：研究尼扎替丁中间体N，N－二甲胺基硫代乙酰胺的合成，考察不同反应温度，反应时间对收率的影响。方法：采用硫氢化钠为催化剂，硫化氢气体直接通入原料N，N－二甲胺基乙腈中反应，然后通过过滤，减压蒸馏得粗品，用异丙醇重结晶得成品，结果：控制反应温度约50℃，通入硫化氢气体反应6小时。结论：该合成方法为N，N－二甲胺基硫代乙酰胺的工业化生产提供了一条新途径。