Assessment of oxidative DNA damage in the oxyR-deficient SOS chromotest strain Escherichia coli PQ300.

The SOS chromotest is a simple short-term genotoxicity assay measuring the induction of gene sfiA in Escherichia coli K-12. The recent availability of SOS tester strains with additional mutations in DNA repair or protection systems allows testing of DNA damaging compounds for genotoxic specificity. E. coli PQ300 differs from the standard SOS tester strain PQ37 in that it contains an additional mutation in gene oxyR that renders it more sensitive to oxidative genotoxins. The generation of reactive oxygen intermediates (ROI) by hydroperoxides (H2O2, t-butyl hydroperoxide, cumene hydroperoxide), gamma-radiation, glucose oxidase, and xanthine oxidase resulted in a more vigorous SOS response in strain PQ300 compared to strain PQ37. PQ300 was also more sensitive than PQ37 for the detection of reducing agents such as ascorbic acid, cysteine, and glutathione, which also alter the redox status of the bacterial cells. However, intercalating agents (adriamycin, bleomycin, and mitomycin C) and the UV- and radiomimetic compound 4-nitroquinoline-1-oxide whose DNA damaging potential are known also to involve ROI did not show significant differences between strains PQ37 and PQ300. It is concluded that the oxyR-deficient strain PQ300 is useful for detecting certain classes of genotoxins that change the oxidative/antioxidative balance of tester bacteria in the SOS chromotest.     

Combined open and laparoscopic approach to chronic pain following open inguinal hernia repair

Introduction: Chronic groin pain is the most common long-term complication after open inguinal hernia repair. Traditional surgical management of the associated neuralgia consists of injection therapy followed by groin exploration, mesh removal, and nerve transection. The resultant hernia defect may be difficult to repair from an anterior approach. We evaluate the outcomes of a combined laparoscopic and open approach for the treatment of chronic groin pain following open inguinal herniorrhaphy. Methods: All patients who underwent groin exploration for chronic neuralgia after a prior open inguinal hernia repair were prospectively analyzed. Patient demographics, type of prior hernia repair, and prior nonoperative therapies were recorded. The operation consisted of a standard three trocar laparoscopic transabdominal preperitoneal hernia repair, followed by groin exploration, mesh removal, and nerve transection. Outcome measures included recurrent groin pain, numbness, hernia recurrence, and complications. Results: Twelve patients (11 male and 1 female) with a mean age of 41 years (range 29–51) underwent combined laparoscopic and open treatment for chronic groin pain. Ten patients complained of unilateral neuralgia, one patient had bilateral complaints, and one patient complained of orchalgia. All patients failed at least two attempted percutaneous nerve blocks. Prior repairs included Lichtenstein (n=9), McVay (n=1), plug and patch (n=1), and Shouldice (n=1). There were no intraoperative complications or wound infections. With a minimum of 6 weeks follow up, all patients were significantly improved. One patient complained of intermittent minor discomfort that required no further therapy. Two patients had persistent numbness in the ilioinguinal nerve distribution but remained satisfied with the procedure. Conclusions: A combined laparoscopic and open approach for postherniorrhaphy groin pain results in good to excellent patient satisfaction with no perioperative morbidity. It may be the preferred technique for the definitive management of chronic neuralgia after prior open hernia repair.     

跨矢状窦脑膜瘤术中矢状窦的处理

目的总结跨矢状窦脑膜瘤术中矢状窦的处理方法.方法对26例跨矢状窦脑膜瘤及受累矢状窦进行切除,依具体情况重建或不重建矢状窦.结果该组病人无手术死亡,手术后均未加重原有神经功能障碍,无脑血液回流障碍,7例重建矢状窦者未发现有矢状窦内血栓形成.结论矢状窦旁脑膜瘤的治疗除肿瘤切除外,对受累上矢状窦处理是否彻底对预防术后复发是至关重要的.对受累矢状窦应按具体情况按一定的原则进行积极处理.     

卡那霉素链霉菌噬菌体SKJ1DNA限制性内切酶图谱的构建

卡那霉素链霉菌温和性噬菌体ＳＫＪ１ＤＮＡ上有２个ＡｖａＩ和ＳｍａＩ酶切位点，８个ＳａｌＩ位点，７个ＥｃｏＲＩ位点及１２个ＢａｍＨＩ位点，经酶切后用１％琼脂糖凝胶电泳测定ＳＫＪ１ＤＮＡ大小为６０．７ｋｂ。用单酶切，双酶切及片段酶切分析，得到ＳＫＪ１ＤＮＡ的ＡｖａＩ、ＳｍａＩ、ＥｃｏＲＩ、ＳａｌＩ酶切图谱及ＢａｍＩ１的部分酶切图谱，证明ＡｖａＩ和ＳｍａＩ在ＳＫＪ１ＤＮＡ上具有相同酶切位点，并经过酶切结     

乙型肝炎病毒免疫逃避株表面抗原决定簇编码区的序列分析

应用聚合酶链反应（ＰＣＲ）产物直接测序，在国内首次发现１例持续高滴度乙型肝炎表面抗原（ＨＢｓＡｇ）和抗一ＨＢｓ共存者携带的乙型肝炎病毒ＤＮＡ第５３２位碱基Ａ被Ｇ取代，推导其“ａ”决定簇中第１２６位苏氨酸被丙氨酸取代，提示该株“ａ”决定簇第一个结构环疏水性增加，由此可能导致其抗原性改变，而诱发免疫逃避株形成。     

Treatment of chronic hepatitis B

SUMMARY. Chronic infection with the hepatitis B virus (HBV) is a major cause of worldwide morbidity and mortality. A large number of therapeutic approaches has been tried, including interferon (IFN), nucleoside analogues and immunomodulators. To date controlled clinical trials have shown that only IFN is of long-term value but many patients fail to respond to treatment. New approaches to treating patients with IFN-resistant hepatitis B are currently undergoing clinical and experimental evaluation, and it seems likely that new therapeutic agents will be available in the near future.     

Quantitative DNA measurement by flow cytometry and image analysis of human nonseminomatous germ cell testicular tumors

Current clinical staging, which includes the use of serum tumor markers and imaging techniques, fails to identify the 30–40% of clinical stage I (CS I) nonseminomatous germ cell testicular tumor (NSGCT) patients who have occult metastatic disease. Therefore, there is a real clinical need to evaluate new biological parameters of the primary tumor that might be useful as predictors of occult metastatic disease. This study was undertaken to compare quantitative DNA measurements by flow cytometry and image analysis in CS I NSGCT, and to analyze the relevance of these parameters for predicting occult lymph node involvement. Different blocks of formalin-fixed, paraffin-embedded NSGCTs of 62 CS I patients who underwent retroperitoneal lymph node dissection between 1985 and 1989 were prepared according to the Hedley technique, and analyzed by quantitative cytometry. Thirty-six (58.1%) patients had histologically proven lymph node involvement (pathological stage II), whereas 26 (41.9%) patients (pathological stage I) had neither lymph node metastases according to retroperitoneal lymph node dissection (RPLND) specimens nor tumor recurrence during follow-up. Concordant results were found in 76.5% of the samples by both cytometric techniques. For flow cytometry, the percentages of aneuploid cells in the S- and the G2M+S-phase were the most robust predictive parameters for lymph node involvement, whereas for image analysis the 5c exceeding rate (5cER) had the most predictive significance. Based on the experience obtained in this study, both cytometric techniques provide additional information on tumor aggressiveness that might be useful in therapeutic selection of early stage NSGCT patients for either RPLND or surveillance only.     

The use of coaxially aligned freeze-thawed skeletal muscle autografts in the repair of the cauda equina — in the sheep

Summary The aim was to develop a model for study of nerve regeneration in nerve roots above the level of the dorsal root ganglion and to investigate the use of freeze-thawed muscle autografts for repair of nerve roots at this level.Four adult sheep were used for the experiment. A laminectomy was performed at the lumbosacral junction and the S2 root identified. Both the dorsal and ventral S2 roots were divided unilaterally within the dura and a freeze-thawed muscle graft was inserted into the nerve gap.When assessed at 6 months an action potential was recordable from the ventral root in one sheep. Histological examination of the nerve roots showed evidence of regeneration across the graft in the ventral roots of all the sheep and the dorsal roots of some.This preliminary work indicates a capacity for regeneration of the cauda equina and that freeze-thawed muscle can support this. It provides a useful model for further study of nerve root repair.     

乳腺囊性增生病癌变过程中部分因素变化的意义

检测乳腺囊性增生病（ＦＣＤ）经不典型增生到癌变部分因素的变化。结果提示：从因明显ＦＣＤ症状活检至癌变为２～１０年；从Ⅱ级以上不典型增生到临床癌变需２～７年；癌变率为３．１％。ＦＣＤ患者存在性激素分泌调控失常，血浆雌激素和催乳素含量增加，导致上皮细胞增生。乳腺一般性增生细胞的ＤＮＡ含量和超微结构与正常乳腺上皮细胞相似；无肿瘤相关抗原及异常基因产物表达。而发生在一般性增生基础上的不典型增生则呈现细胞基因物质ＤＮＡ含量增加，部分为超４Ｃ的多倍体细胞；同时出现细胞膜和细胞核超微结构异常；雌激素受体含量增加，对性激素的依赖性和敏感性增强；部分不典型增生细胞出现胚胎性肿瘤相关抗原和异常基因产物表达。随不典型增生程度加重至乳腺癌，上述诸因素的变化趋势具有明显规律性。提示ＦＣＤ上皮细胞从一般性增生经不典型增生至乳腺癌为细胞生物学连续逐渐变化的过程。部分不典型增生细胞中具有癌倾向的细胞生物学行为异常和表型变化与乳腺癌发生密切相关。细胞核ＤＮＡ含量等异常变化及程度可作为乳腺癌前病变发展程度的客观标志