Release of sulfur mustard-modified DNA bases by Escherichia coli 3-methyladenine DNA glycosylase II

The toxic effects of sulfur mustard have been attributed toDNA modification with the formation of 7-hydroxyethyl-thioethylguanine, 3-hydroxyethylthioethyl adenine and the cross-link,di-(2-guanin-7-yl-ethyl)sulfide. To investigate the action ofbacterial 3-methyladenine DNA glycosylase II (Gly II) on theseadducts, calf thymus DNA was modified with [¹⁴C]sulfur mustardand used as a substrate for Gly II. Gly II releases both 3-hydroxyethylthioethyladenine and 7-hydroxyethylthioethyl guanine from this substrate.In comparison with the activity of Gly II towards methylatedDNA, 3-hydroxyethylthioethyl adenine is released somewhat moreslowly than 3-methyladenine, while 7-hydroxyethylthioethyl guanineis released much more readily than 7-methylguanine. Glycosylaseaction may play a role in protecting cells from the toxic effectsof sulfur mustard.     

高原人体体力测试及相互比较

本文研究了平原人移居海拔3680m后,不同时间体力状况,并与条件相近的藏族世居者进行了比较。研究结果表明,移居者的屏气时间较短,表明其缺氧耐受力低。低氧环境对60m跑和握力等无氧运动项目的影响不大。世居者与平原人相比,Vo_2rmax等指标均低于平原人,表明即使对低氧环境产生习服的人体,也不可能达到平原水平,机体的代偿调节能力是有限的。移居者的Vo_2rmax和HBmax等经过7～15个月的适应,可接近世居者水平。但1000m跑成绩大大低于世居者,可能是两种人群对Vo_2rmax的利用率不同引起。     

MRI增强扫描对脑转移瘤的诊断价值

目的 总结磁共振增强扫描在脑转移瘤诊断中的重要价值。方法 脑转移瘤32例，均经病理和临床证实，全部病例均做了Gd-DTPA增强前后扫描。结果 脑转移瘤单发15例，多发17例，发生在幕上26例，幕下6例，幕上幕下并存4例。病灶最大径在0．5cm～6cm，平均2．4cm。发现病灶数：T1WI40个，T2WI56个，增强后发现116个。结论 增强扫描发现的脑转移瘤病灶明显多于平扫，并且能分清病灶与瘤周水肿的界限，从而明确其发生的部位、数目、形态、和大小，结合临床和影像学特征，容易作出正确诊断。     

Research on Autoantibodies Against Myocardial β1-adrenergic and M2 Cholinergic Receptors in Patients With Chronic Keshan Disease

Objectives To explore the relationship between serum autoantibodies against myocardialβ1-adrenergic, M2-cholinergic receptors and chronic Keshan disease (CKD). Methods The second extracellular loops ofβ1 and M2 receptors on human cardiomyocytes were used as the antigens. Enzyme linked immunosorbent assay (ELISA) was applied to determine serum autoantibodies against myocardialβ1 and M2 receptors in 32 CKD patients. 31 healthy subjects from endemic area were selected as the control. Results Positive rate of autoantibodies against myocardialβ1 adrenergic (51.3%, 17/32) and M2 cholinergic (56.3% , 18/32) receptors were significantly higher than those in the control (9.7%, 3/ 31; 12.9%, 4/31) (both P< 0.01). Both positive rate and liters of above autoantibodies in NYHAⅡ-ⅢCKD patients were significantly higher than those in NYHAⅣ, demonstrating an apparently positive correlation between serum antibodies against myocardialβ1 and M2 receptors (r=0.95). Conclusions Autoantibodies against myocardialβ1 and M2 receptors were found in sera of CKD patients; distribution of positive rate and liters of the auloanlibodies in CKD patients in various NYHA classes of cardiac function are significantly different.     

心肌缺血再灌注时内皮细胞损伤功能改变与心肌梗塞面积的关系

目的旨在探讨内皮细胞损伤、功能改变在心肌缺血再灌注（ＭＩＲ）损伤中的发病机制及其与心肌梗塞面积的关系及卡托普利的保护作用。方法用２４只麻醉兔随机分为三组，（１）ＭＩＲ组，（２）ＭＩＲ＋卡托普利治疗组，（３）假手术对照组，观察心肌缺血半小时，再灌注０．５、１．５、６小时血循环内皮细胞（ＣＥＣ），一氧化氮（ＮＯ），内皮素（ＥＴ）的含量变化及其与心肌梗塞面积的关系，静注卡托普利观察其对梗塞面积及上述指标的影响。结果（１）与假手术组比较，再灌注半小时，血ＮＯ下降，ＥＴ升高，其变化于再灌注６小时最明显（Ｐ＜０．０５），ＣＥＣ则以再灌注１．５小时明显增高（Ｐ＜０．０５）；（２）再灌注６小时心肌梗塞范围较治疗组明显增加（Ｐ＜０．０５），且同一时相点血ＮＯ与心肌梗塞面积呈负相关（ｒ＝－０．９６１，Ｐ＜０．０１），血ＥＴ与心肌梗塞面积呈正相关（ｒ＝０．９２３，Ｐ＜０．０５）；（３）用卡托普利干预后，血ＮＯ有所回升，ＥＴ明显下降，心肌梗塞面积明显缩小。结论ＭＩＲ可诱发内皮功能紊乱，而内皮功能紊乱是再灌注心肌损伤加重的始动因素     

Giant bronchogenic cyst masquerading as tension pneumothorax radiographic and CT findings

Pulmonary bronchogenic cysts with tracheobronchial communication may occasionally mimic tension pneumothorax leading to unnecessary thoracostomy. We describe such a case to emphasize that cautious identification of the direction of displacement of the collapsed lung tissue on chest radiograph or computed tomography (CT) may help in differentiating these two diseases. Tension pneumothorax should lead to centripetal compression of the ipsilateral lung toward the hilum while giant bronchogenic cysts result in centrifugal displacement of the adjacent lung away from the hilum.     

肺鳞癌间质内肥大细胞计数的意义

①目的探讨间质内的肥大细胞与肺鳞癌生物学行为的关系。②方法采用甲苯胺蓝染色检测８９例经手术切除的肺鳞癌标本间质内每１０个高倍视野的肥大细胞数。③结果Ⅰ，Ⅱ级鳞癌中肥大细胞数明显多于Ⅲ级（ｔ＝２．９４，２．７４，Ｐ均＜０．０１），肿瘤直径＞５ｃｍ组的肥大细胞数明显少于３～５ｃｍ组和＜３ｃｍ组（ｔ＝３．１３，２．４２，Ｐ＜０．０１，０．０５），０．５年内死亡组肥大细胞数明显少于５年以上生存组和０．５～５．０年内死亡组（ｔ＝３．６８，２．７５，Ｐ＜０．０１），肥大细胞计数在有无淋巴结转移两组病人间差异无显著性（ｔ＝１．８５，Ｐ＞０．０５）。④结论肥大细胞与肺鳞癌细胞的分化、生长和病人预后有关，且具有一定的抗肿瘤作用。     

转导白细胞介素2基因的B16细胞对机体免疫反应的影响

应用XM6逆转录病毒载体将人IL-2cDNA转入小鼠B16黑色素瘤细胞。丝裂霉素C处理的转染前后B16细胞作为瘤苗对小鼠进行免疫接种。结果显示，接种B16-IL-2细胞可明显排斥再移植黑色素瘤的生长。对脾淋巴细胞检测的结果表明，MLTR引起的淋巴细胞增殖与特异性CTL杀伤活性，以及NK、LAK活性与诱生的IL-2水平几项指标，B16-IL-2细胞免疫组均明显高于B16免疫组及对照组。提示转基因肿瘤细胞在体内分泌IL-2增强了机体的特异性与非特异性免疫功能。     

氯化四乙基铵及维拉帕米对家兔缺血心肌不应期的影响

实验比较了K⁺通道阻断剂氯化四乙基铵(TEA)及Ca²⁺通道阻断剂维拉帕米(verapamil,Ver)对家兔缺血性心室肌不应期(ERP)的影响。结果表明,阻断冠脉10min及30min后,缺血中心区(CIZ)和缺血边缘区(BIZ)心肌ERP比缺血前均明显缩短,而TEA和Ver均能延长急性缺血性心肌的ERP,可能对心肌缺血引起的心律失常有预防作用。     

三硝基甲苯的遗传毒性研究

用果蝇伴性隐性致死（ＳＬＲＬ）实验和非整倍体检测实验，对三硝基甲苯（ＴＮＴ）的遗传毒性进行了研究。结果表明：雄性果蝇在５４．０ｍｇ、２７．０ｍｇ、１３．５ｍｇ／１００ｍｌ培养基浓度下喂饲２４小时，在ＳＬＲＬ实验中，可引起生殖细胞隐性致死率明显增加，并有明显的剂量反应关系；在非整倍体检测实验中，Ｘ或Ｙ染色体丢失率明显增加，也有明显的剂量反应关系。说明ＴＮＴ对果蝇生殖细胞具有明显的致突变作用。分阶段（２，３，３天）实验表明，ＴＮＴ对果蝇各阶段生殖细胞具有相同的致突变作用。