Neuroprotective mechanism of glial cell line-derived neurotrophic factor on dopamine neurons: role of antioxidation.

Recombinant human GDNF was infused into the rat striatum either acutely or subchronically. Its effects and its interactions with MPP+ on antioxidant enzyme activities were examined. Results indicated that acute GDNF infusion significantly increased glutathione peroxidase, superoxide dismutase and catalase activities. Subchronic GDNF treatment decreased the DA level and enhanced DA turnover. Pre-treatment with GDNF markedly protected DA neurons against MPP+-induced toxicity. These results suggest that GDNF protects DA neurons through its activation of the antioxidant enzyme systems.     

Inhibition by arsenite of anticancer drug cis-diamminedichloroplatinum(II) induced DNA repair and drug resistance in HeLa cells

We have previously reported a cisplatin-resistant HeLa variant cell line (HeLa/CPR) which exhibited an enhancement in repairing cisplatin-DNA adducts (Chao, 1994, Mol. Pharmacol. 45, 1137-1144). In this study, using this cell line, we investigated the modification, by arsenite, of cisplatin-induced cytotoxicity and DNA repair in the resistant cell line. By a sublethal dose of arsenite, cytotoxicity of the resistant cells was enhanced by 2.5-fold, compared to 1.62-fold in the parental cells. Using enzyme-linked immunosorbent assay (ELISA) and a monoclonal antibody specific for cisplatin-DNA adducts, we found that the resistant cells showed a 5.15-fold decrease in the adduct formation compared to the parental cells. However, in the presence of arsenite, the resistant cells showed only a 1.47-fold decrease in the adduct formation, indicating a more than 3-fold modification. Using host cell reactivation of transfected plasmid DNA carrying cisplatin damage (an indirect detection of DNA repair), arsenite also revealed a ～2-fold modification of adduct formation in the resistant cells. In addition, the time-dependent potentiation of cytotoxicity by arsenite in both cell lines was parallel to the increase of adduct formation. These results indicate that arsenite is an effective modifier of cisplatin-induced resistance and enhanced DNA repair in HeLa/CPR cells. The results are consistent with the notion that the cisplatin-resistant phenotype in HeLa cells is mainly mediated by enhancement of DNA repair.     

三日龄大鼠缺氧缺血性脑损伤对大脑MRI影像和学习记忆能力的远期影响

Objective To investigate the activation of apoptotic genes of the brain with hypoxia- ischemia (HI) in newborn SD rats, and MRI changes and memory and learning ability in adulthood. Methods HI was induced by right carotid artery ligation followed by 2.5 h of hypoxia (6% O2) on 3-day-old SD rats (n=36). Control pups were sham-operated (n = 27). Right brain hemisphere was collected at 12 h and 7 d after HI and subjected to an apoptosis Oligo GEArrayR. MRI and Morris water maze test were performed on both groups at 42 and 44 days old, respectively. Results Comparing to 12 h after HI, up-regulated apoptotic genes included TNF, Caspase and pro-apoptotit genes of Bcl2 families, whereas the anti-apoptotic genes of Bcl2 family were down-regulated at 7 d after HI. The MRI assessment of the rats in HI group demonstrated that the area of the right cerebra l cortex was significantly smaller than the left side and control [periventricular layer: (23.5±3.6) mm2 vs (33.0±4.3) mm2, (34.5±3.9) mm2; hippocampus layer: (18.9±4.4) mm2 vs (29.1±5.0) mm2,(30.8±4.5) mm2, both P<0.01]. During the navigation trial, the HI rats demonstrated longer escape latency (4th day: (52.7±35.9) vs (17.8±8. 9) s, P<0.01). HI rats passed the platform less times than the control ones (T= 292.5, P<0.05) in space probe trial. Conclusions The activation of apoptotic genes induced by HI brain injury remains until 7 days later, involving intrinsic and extrinsic apoptotic pathway. The apoptosis of neural cells may lead to poor development of the cortex and impair the memory and learning ability in the adult rats after neonatal hypoxia- ischemia injury.     

CT-based delineation of lymph node levels and related CTVs in the node-negative neck: DAHANCA, EORTC, GORTEC, NCIC,RTOG consensus guidelines.

BACKGROUND AND PURPOSE: The appropriate application of 3-D CRT and IMRT for HNSCC requires a standardization of the procedures for the delineation of the target volumes. Over the past few years, two proposals--the so-called Brussels guidelines from Grégoire et al., and the so-called Rotterdam guidelines from Nowak et al.--emerged from the literature for the delineation of the neck node levels. Detailed examination of these proposals however revealed some important discrepancies. MATERIALS AND METHODS: Within this framework, the Brussels and Rotterdam groups decided to review their guidelines and derive a common set of recommendations for delineation of neck node levels. This proposal was then discussed with representatives of major cooperative groups in Europe (DAHANCA, EORTC, GORTEC) and in North America (NCIC, RTOG), which, after some additional refinements, have endorsed them. The objective of the present article is to present the consensus guidelines for the delineation of the node levels in the node-negative neck. RESULTS AND CONCLUSIONS: First a short discussion of the discrepancies between the previous Brussels and the Rotterdam guidelines is presented. The general philosophy of the consensus guidelines and the methodology used to resolve the various discrepancies are then described. The consensus proposal is then presented and representative CTVs that are consistent with these guidelines are illustrated on CT sections. Last, the limitations of the consensus guidelines are discussed and some concerns about the direct applications of these guidelines to the node-positive neck and the post-operative neck are described.     

KTP Laser and Neutral Red Phototherapy of Human Squamous Cell Carcinoma

Neutral red (NR) is a cationic, nontoxic vital dye employed as a histologic stain for proliferating cells; it has been used clinically for photodynamic treatment of herpes simplex virus lesions. NR is selectively taken up and concentrated by mitotic cells, an important characteristic for more effective antineoplastic agents. In the present study, UCLA-SO-P3 human squamous carcinoma cells displayed minimal toxicity when incubated with up to 50 μg/ml NR in the absence of light. However, cells incubated with greater than 0.5μg/ml NR followed by exposure to KTP laser light at 532 nm exhibited nearly 100% tumor cell death. The degree of cell toxicity was proportional to NR dose and laser light fluence. This study demonstrates that NR is an excellent cancer cell photosensitizer in vitro, and, after adding additional in vivo preclinical testing, may prove to be a useful agent in photodynamic destruction of head and neck tumors.     

A simplified technique for embryo biopsy: Use of the same micropipette for zona drilling and blastomere aspiration

Purpose: Using different micropipettes for zona drilling and blastomere aspiration for embryo biopsy is prevalent at centers of preimplantation genetic diagnosis. The purpose of our study was to simplify the technique by using only one micropipette. Methods: In this animal model, ICR mouse embryos at the four-cell stage (n=446) were randomly allocated into two groups: a biopsied group (n=224) for blastomere aspiration and a control group (n=222) without micromanipulation. We used a drilling/biopsy micropipette to drill a hole in the zona by expulsion of acidified Tyrode’s solution and to aspirate the blastomere by gentle suction with the same micropipette and pull it out of the zona. One blastomere was biopsied from each embryo. Results: In all, 222 (99.1%) intact blastomeres were successfully biopsied from 224 embryos. Only two blastomeres were damaged during aspiration. The capacity for blastocyst development (92.4 vs 93.7%) was not different between the two groups, but the percentages of embryos hatching (51.8 vs 18.0%) and hatched (29.9 vs 8.1%) were significantly higher in the biopsied group than in the control group. Conclusions: This simplified technique of embryo biopsy is safe and highly efficient for obtaining blastomeres for preimplantation genetic diagnosis and may also facilitate hatching of the blastocysts.     

声门上型喉癌临床N_0病理转移的观察

目的：为探讨喉癌颈淋巴结转移的规律，选择手术方法。方法：采用１１０例临床Ｎ０声门上型喉癌的１６４侧颈廓清术标本淋巴结连续切片方法观察。结果：发现颈淋巴结转移率为３５．５％（３９／１００）。提出临床Ｎ０病理转移的特点：１）转移淋巴结大小大多数介于０．５～１．５之间占８４．２％。２）转移淋巴结大多数为早期侵入期和生长发展期占８６．０％。３）转移淋巴结绝大多数为单发型占７４．４％。４）各个Ｔ分期均有转移淋巴结。结论：在颈淋巴结处理上，我们支持尽可能同期行选择性颈廓清术的观点     

Focal cerebral ischemia alters the spatio-temporal properties, but not the amount of locomotor activity in mice

Cerebral ischemia induces hyperlocomotion in gerbils, and sensorimotor and cognition dysfunctions in rodents ; however little is known about the spatio-temporal organization of locomotor activity after ischemia. In this study, we continuously （22 h） assessed the spatio-temporal organization of locomotor activity in focal cerebral ischemic mice in an open field with feeding and drinking supplies. To observe the spatio-temporal changes,     

青春期的性生理特征及其卫生教育

了解青春期的生理变化特征及其卫生,对青少年身心的健康成长和良好心理素质的培养具有重要意义.文章通过对青春期性心理特征的分析,重点阐述了如何对青少年加强性心理与心理卫生的教育.