The Protective Role of Glutathione, Cysteine and Vitamin C against Oxidative DNA Damage Induced in Rat Kidney by Potassium Bromate

The roles of glutathione (GSH), cysteine, vitamin C., liposome-encapsulated superoxide dismutase (L-SOD) and vitamin E in preventing oxidative DNA damage and cytotoxicity in the rat kidney after administration of potassium bromate (KBrO₃) to male F344 rats were investigated by measuring 8-hydroxydeoxyguanosine (8-OH-dG), an oxidative DNA product, lipid peroxidation (LPO) levels and relative kidney weight (RKW). Combined pre- and posttreatment of animals with 2 × 800 mg/kg GSH i.p. inhibited the increase of 8-OH-dG, LPO levels and RKW caused by 80 mg/kg KBrO₃ i.p. administration. In contrast, pretreatment with 0.3 ml/kg diethylmaleate (DEM) i.p., a depletor of tissue GSH, was associated with elevation of 8-OH-dG, LPO levels and RKW after a 20 mg/kg KBrO₃ i.p. treatment, which itself caused no change. Administration of KBrO₃ itself reduced renal non-protein thiol levels, but this was inhibited by the two doses of exogenous GSH. Combined treatment with DEM and KBrO₃ lowered the non-protein thiol level in the kidney more than did DEM treatment alone. Protective effects against the oxidative damage caused by KBrO₃ were also observed for pre- and posttreatment with 400 mg/kg cysteine i.p., another sulfhydryl compound, and daily i.g. application of 200 mg/kg vitamin C for 5 days. However, no influence was evident after pre- and posttreatment with 18,000 U/kg L-SOD i.p. or daily i.g. 100 mg/kg of vitamin E for 5 days. The results suggest that intracellular GSH plays an essential protective role against renal oxidative DNA damage and nephrotoxicity caused by KBrO₃.     

Ubiquitous Presence in Mammalian Cells of Enzymatic Activity Specifically Cleaving 8-Hydroxyguanine-containing DNA

Here we report the finding of enzymatic activity that specifically cleaves DNA containing 8-hydroxyguanine (oh⁸Gua) residues in various mammalian cells. To detect this activity, we used a synthetic double-stranded DNA containing a single oh⁸Gua at a defined position as the substrate, and analyzed the products of enzymatic digestion by polyacrylamide gel electrophoresis. Two cleavage sites near the oh⁸Gua residue were detected with partially purified fractions from cow brain and rat liver, and also with preparations from all mammalian tissues examined. These results suggest that enzymatic activity for the removal of oh⁸Gua from DNA is widely distributed in mammalian cells.     

小包装全氟丙烷气体动力学实验研究

为检验塑料小包装全氟丙烷气体（C3F8）在不同包装和储存方法时浓度变化，将装有5～7mlC3F8的聚氯乙烯小袋，根据不同储藏温度和外包装方法随机分成四组：（1）22℃聚乙烯外包装，（2）36℃聚乙烯外包装，（3）22℃铝箔真空外包装，（4）-29℃聚乙烯外包装；每一组C3F8小袋气体存放一定时间后，应用气相色谱分析方法进行浓度测量。结果：第3组C3F8浓度最高和稳定，第2组浓度随放置时间降低最明显，第4组是临床应用气体的储藏和包装方法，其30天样本浓度和第3组相等，但放置一年时浓度降低。结果显示：塑料小包装C3F8予以铝箔真空外包装是一种可行的方法，利于C3F8运输和普及；聚乙烯外包装的C3F8，应放在-29℃保存，时间不超过一年。     

Endolymphatic sac surgery: analysis of 100 operations*

One hundred endolymphatic mastoid shunt operations in 89 patients with classical Menière's disease were analysed. The disease was bilateral in 18 patients (20%). The patients were carefully pre-selected by a comprehensive protocol of audiovestibular and metabolic investigations. All patients had definite electrophysiological evidence of endolymphatic hydrops with an enhanced negative summating potential on transtympanic electrocochleography. The surgical results were analysed both by the original American Academy of Ophthalmology and Otolaryngology Guidelines (AAOO, 1972) and the more recent modifications of the American Academy of Otolaryngology, Head and Neck Surgery (AA-HNS, 1985). Control of the vertigo was achieved in 81% of the patients overall, in 88% of the patients with unilateral disease and in 63% of the patients with bilateral disease. A significant hearing improvement was obtained in 19% of patients, no change in 55% and hearing became worse in 26%. Tinnitus improved in 38% of patients, was unchanged in 52% and became worse in 10%. Disability was assessed and there was no disability in 44% of the patients post-operatively, some degree of disability in 48% but only 8% were severely disabled and unable to sustain gainful employment.     

精氨酸加压素（AVP）的衍生物AVP4—8不能作用于AVPV1a受体而诱发电流反应

在微量注射大量肝脏ｍＲＮＡ之后，通过电压箝方法进行功能鉴定，两栖类卵母细胞成功地表达了ＡＶＰＶ１ａ受体。但在灌流ＡＶ４－８溶液时，却不能诱导卵母细胞产生内向振荡电流反应。提示ＡＶＰ４－８不能通过ＡＶＰＶ１ａ受体而介导生理学效应。     

Effect of interleukin-8 on glomerular sulfated compounds and albuminuria

To evaluate the effect of interleukin-8 (IL8) on glomerular basement membrane (GBM) sulfated compounds and albuminuria, we infused IL8 in 1% bovine serum albumin (BSA) for 5 days into the left renal artery of Holtzman male rats at the rate of 10 μl/h using an osmotic pump. Control rats received 1% BSA. A significant increase in urinary albumin/creatinine ratio was seen on the last day of IL8 infusion (0.38±0.11, mean ± SEM) when compared with albumin/creatinine ratio prior to infusion (0.19±0.04, P = 0.04). No significant differences in urinary albumin excretion prior to and after infusion of 1% BSA were observed. On the last day of infusion, rats were injected with ³⁵sulfate (1.0 mCi/200 g body weight) intraperitoneally and killed after 8 h. Glomeruli were isolated and GBM obtained. After 5 days of IL8 administration, there was a significant increase in ³⁵sulfate uptake by GBM of the infused kidney (76±10 cpm/dry glomerular weight, mean ± SEM) compared with the uptake seen in the contralateral kidney (53±9, P = 0.05). The in vivo infusion of IL8 increased the ³⁵sulfate uptake by GBM and augmented the urinary albumin/creatinine ratio, suggesting that IL8 may induce albuminuria by altering the metabolism of the GBM sulfated compounds. This hypothesis needs to be confirmed by studies on glomerular charge selectivity and GBM anionic sites during the course of the infusion. Moreover, the persistence of the effect needs to be evaluated by prolonging the infusion for more than 5 days. Received June 3, 1996; received in revised form and accepted October 18, 1996     

Inhibition of HLA B8-restricted recognition by unrelated peptides: evidence for allosteric inhibition

A panel of synthetic peptides representing human lymphocyte antigen (HLA) B8, other class I and class II restricted T cell epitopes and two B cell epitopes, were all able to compete with recognition of a HLA B8 restricted epitope by a cytotoxic T cell clone. Competition was obtained when the competitor peptides were added either before or after the target epitope. The target epitope also had a slow off rate, implicating allosteric inhibition. The presence of non-specific, allosteric binding sites may interfere with experiments attempting to define immunologically relevant MHC binding specificities.     

A Comparative Study on the Effect of BCG-PSN and Thymopeptides on T-lymphocyte Subsets of Normal and Immunosuppressed Mice

Polysaccharidenucleicacidfractionofbacilluscalmetteguerin (BCG PSN ,SiqikangInjection)andthymopeptidesarenowtwowidelyusedimmunomod ulatorsinclinicalpractice .Theyareusuallyusedasanadjuvanttherapyforvirusinfection ,autoimmunediseasesandneoplasms ,whichhavebeenclinicallyprovedtobeeffective .Somereportsdemonstratedthattheybothcanstimulatetheproliferationanddif ferentiationofT lymphocytes.However ,theexactmechanismshavenotbeenelucidatedyet .InordertocomparetheirmodulatingmechanismsonT lympho c…     

溴环己胺醇预先给药对大鼠盐酸吸入性肺损伤的作用

目的 观察溴环己胺醇预先给药对大鼠盐酸吸入性肺损伤是否具有保护作用，并探讨其可能机制。方法30只健康 SD 大鼠，随机分成3组，A 组：生理盐水吸入组；B组：稀盐酸吸入组；C组：稀盐酸吸入 溴环己胺醇处理组，每组10只。C 组腹腔注射溴环己胺醇，1次/d，连续3d，A、B 组以等体积生理盐水代替。第3天注药后30min，B、C 组气管注入pH 值为1.25的稀盐酸1.2ml/kg，制成盐酸吸入性肺损伤模型，A 组气管注入生理盐水1.2ml/kg。观察注药后5h 动脉血气、氧合指数(PaO_2/FiO_2)、肺湿/干重比(W/D)、肺组织及血清中肿瘤坏死因子-α(TNF-α)、白细胞介素-8(IL-8)水平。结果 与 A 组比较，B、C 组 PaO_2、PaO_2/FiO_2降低(P<0.01)，B、C 组W/D、B 组肺组织 TNF-α、IL-8含量、血清 IL-8浓度升高(P<0.01)。与 B 组比较，C 组 PaO_2、PaO_2/FiO_2升高(P<0.01)，C 组W/D、肺组织TNF-α、IL-8含量及血清 IL-8浓度降低(P<0.01)。结论 溴环己胺醇可能通过抑制 TNF-α、IL-8炎症因子的产生和释放机制对盐酸吸入性损伤肺产生保护作用。