灰鼠疆孔内听神经纤维的定量观察

目的为了观察正常灰鼠和卡铂（Ｃａｒｂｏｐｌａｔｉｎ）耳中毒灰鼠耳蜗单个疆孔（ｈａｂｅｎｕｌａｐｅｒｆｏｒａｔａ）内的神经纤维数量。方法１２只灰鼠中６只按１００ｍｇ／ｋｇ腹腔注射卡铂２次，６只作正常对照，３个月后处死，沿蜗轴平面作半薄切片，甲苯胺蓝－美蓝染色后光镜观察，组间统计学比较采用ｔ检验。结果正常灰鼠的神经纤维数量在耳蜗不同部位有所不同，其中在底回起始段每个疆孔中通过９３．７±１２．２（ｘ±ｓ，下同）根神经纤维，底回末段为１８１．５±３０．４，第二回中段为１２９．７±２７．８，顶回中段为７５．８±１３．２。应用加倍大剂量卡铂将内毛细胞和Ｉ型螺旋神经元全部破坏后，疆孔内残存的神经纤维数仅占正常值的七分之一。结论疆孔内七分之六的神经是支配内毛细胞的Ｉ型神经元。     

人His6-IFNγ/TNFβ(His6γ-TNFNβ)融合蛋白(包涵体)的分离、纯化与复性研究

应用pET28(含T_7lac启动子和His6-tag)质粒,将人γTNFβ融合基因与之组建成pETγLT表达质粒,并转化于E.coliBL21(DE3).本文对pETγLT/ BL21(DE3)工程菌的His6-γTNFβ重组产物进行了诱导表达,分离纯化的研究.结果表明,该工程菌用LB培养基在37℃扩增至OD_(590)为0.5左右,加IPTG(终浓度为1mmol/L)诱导5小时,此时His6-γTNFβ的表达量可占菌体总蛋白的45%.重组产物绝大多数以IBs形式存在于菌体中.工程菌经反复超声破碎、高速离心,得IBs粗制品后,再经含2mol/L脲的缓冲液洗涤可得到相对纯净的IBs.然后用7mol/L脲变性溶解IBs,离心取上清,进行Ni~(2 )-Sepharose 6B柱一步法亲和层析,可得到电泳纯度为95%的His6-γTNFβ,经稀释复性和用凝血酶切去His6-tag的产物,其细胞毒活性为(1.2～2.0)×10~7U/mgp,抗病毒活性为(6.0～6.6)×10~6U/map.     

盐酸恩丹西酮预防化疗所致呕吐Ⅱ期临床研究

观察国产５－ＨＴ３阻滞剂－盐酸恩丹西酮预防化疗所致呕吐的临床疗效。方法：采用随机自身交替对照方法分为两组观察，接受顺铂联合化疗组及非顺铂联合化疗组各２５例。盐酸恩丹西酮８ｍｇ，化疗前１５分钟静注，恩丹西酮８ｍｇ，化疗后８小时口吸口服。对照组：胃复安２０ｍｇ，化疗前１５分钟肌注，胃复安８ｍｇ化疗后８小时口服。     

Synthesis and evaluation of 6-[(18)F]fluoro-3-(2(S)-azetidinylmethoxy)pyridine as a PET tracer for nicotinic acetylcholine receptors

Both ABT-594 ((R)-2-chloro-5-(2-azetidinylmethoxy)pyridine) and A-85380 (3-[2(S)-2-azetidinylmethoxy]pyridine), novel nicotinic agonists that possess potent non-opioid analgesic properties, have high affinity for neuronal nicotinic acetylcholine receptors (nAChR) but do not elicit the pronounced toxicity of epibatidine. 6-[(18)F]Fluoro-3-(2(S)-azetidinylmethoxy)pyridine (6-[(18)F]fluoro-A-85380), a F-18 labeled analogue of these two compounds, is therefore a promising radioligand for positron emission tomography (PET) studies in humans. The use of trimethylammonium as a leaving group in nucleophilic aromatic substitution reactions has proven to be a versatile and efficient strategy, and offers several advantages over other leaving groups. Here, we report the synthetic strategy for the preparation of a precursor, as a trimethylammonium iodide salt, and its use in the radiosynthesis to 6-[(18)F]fluoro-A-85380. Preliminary compartative PET studies of 6-[(18)F]fluoro-A-85380 and 2-[(18)F]fluoro-A-85380 were carried out in baboon to examine their suitability as tracers for studying nAChR system.     

Increased chromatid-type chromosomal aberrations in mouse m5S cells exposed to power-line frequency magnetic fields

PURPOSE: To investigate the induction of chromosomal aberrations in mouse m5S cells after exposure to power-line frequency magnetic fields (extremely low frequency magnetic fields; ELFMF) at high-flux densities. MATERIAL AND METHOD: m5S cells were either untreated or pretreated during the G1 phase with mitomycin C (MMC, 1 microM) for 1 h or 3 Gy X-rays, and then exposed to ELFMF at three different flux densities (5 and 50 mT at 60 Hz, 400 mT at 50 Hz) for 40 h. Unexposed control cells were incubated for the same period in a conventional CO2 incubator. Chromosomal aberrations were analysed in the first post-treatment metaphases. Cell kinetics were assessed by DNA flow cytometry and the mitotic index. RESULTS AND CONCLUSIONS: ELFMF enhanced the formation of spontaneous and MMC- or X-ray-induced chromosomal aberrations, in a flux-density-dependent manner. Statistically significant increases in the frequency of chromosomal aberrations were observed in cells exposed to 400 mT ELFMF with respect to unexposed controls. The aberrations induced by ELFMF were mostly chromatid-type, not chromosome-type. The cells exposed to 400 mT ELFMF exhibited a three-fold higher level of chromatid-type aberrations than did the unexposed cells. Flow cytometric and mitotic index analyses revealed that the S or G2 arrest following MMC or X-irradiation was more profound in ELFMF-exposed cells than in unexposed cells. Our results suggest that ELFMF can interfere with post-replication repair, resulting in increased levels of chromatid-type chromosomal aberrations induced spontaneously and by DNA damaging agents.     

豚鼠耳蜗部分外支持细胞的分离法

目的 :探讨豚鼠耳蜗部分外支持细胞 (Deiter细胞、Hensen细胞和外柱细胞 )的分离方法 ,并建立细胞活性的鉴别标准。方法 :选取健康杂色豚鼠 5只 ,解剖出耳蜗基底膜 ,采用酶解加机械吹打法分离Deiter细胞、Hensen细胞和外柱细胞。结果 :可以获得较多数量、活性良好、长短不一的Deiter细胞和Hensen细胞 ,8h内细胞活性较好 ;但外柱细胞数量较少 ,存活时间较短。评价Deiter细胞、Hensen细胞和外柱细胞的活性标准 :①细胞膜无膨胀或扭曲 ;②细胞核无肿胀、移位 ;③在相差显微镜下细胞呈半透明状态 ,存在双折射现象 ;④细胞内无呈布朗运动的颗粒。结论 :熟悉耳蜗的解剖特性、分离出完整的基底膜 ,增加酶的浓度和加大机械吹打力度是获取活性良好的Deiter细胞、Hensen细胞和外柱细胞的关键 ;评价外毛细胞活性的 4项标准同样可用于判断Deiter细胞、Hensen细胞和外柱细胞的活性     

固相化细胞吸附浓集法分离污水中脊髓灰质炎病毒的实验研究

〔目的〕建立一个适用于污水中脊髓灰质炎病毒分离培养的方法。〔方法〕采用固相化的L2 0B细胞吸附法 ,浓集污水中的脊髓灰质炎病毒 ,将浓集物再用活的L2 0B细胞培养。〔结果〕能够检出 10 0 0ml水中的 0 .1～ 10TCID50 量的脊髓灰质炎病毒 ,在10 0 0ml预处理后的污水中加入 10TCID50 量的病毒 ,亦可以检出。〔结论〕本方法的有效检出限为 10TCID50 / 10 0 0ml,可用于污水中的脊髓灰质炎病毒的浓集和分离培养。     

被忽视的宝贝

小测试 Q1：你去菜场买肉的时候,是不是从不要肉皮？ Q2：清洗鱼的时候,你是不是将鱼鳞和鱼的内脏一起扔掉？ Q3：吃鱼的时候,你是不是也很随意地丢掉了鱼眼睛？ Q4：你是不是只吃过辣椒,而从没尝试过辣椒叶的味道？     

Causal influences in primate cerebral cortex during visual pattern discrimination

Anatomical studies of the visual cortex demonstrate the existence of feedforward, feedback and lateral pathways among multiple cortical areas. Yet relatively little evidence has previously been available to show the causal influences of these areas on one another during visual information processing. We simultaneously recorded event-related local field potentials (LFPs) from surface-to-depth bipolar electrodes at six sites in the ventral region of the right hemisphere visual cortex in a highly trained macaque monkey during performance of a visual pattern discrimination task. Applying a new statistical measure, the short-time directed transfer function (STDTF), to the LFP data set, we charted the changing strength and direction of causal influence between these cortical sites on a fraction-of-a-second time scale. We present results showing, for the first time, the dynamics of distinct feedforward, feedback and lateral influences in the ventral portion of the primate visual cortex during visual pattern processing.