Coplanar PCBs in fish and mussels from marine and estuarine waters of New York State.

Thirty samples of striped bass from marine and estuarine waters of New York State, six samples of mussels from Long Island Sound, and one composite sample of freshwater mussels from Troy were analyzed by a recently developed method which combines sulfuric acid cleanup, carbon chromatography, and high-resolution gas chromatography for the determination of non-ortho- and mono-ortho-substituted polychlorinated biphenyls (PCBs), which are biologically active congeners of PCBs and approximate isostereomers of 2,3,7,8-tetrachlorodibenzo-P-dioxin of (2,3,7,8-TCDD). Non-ortho coplanar PCBs ranged from 0.2 to 37.1 ppb in fish. The highest concentrations of 37.1 ng/g of 3,3',4,4'-tetrachlorobiphenyl (77) and 7.5 ng/g of 3,3',4,4',5-pentachlorobiphenyl (126) were detected in a fish caught near Troy/Albany, New York. Mono-ortho-substituted PCBs ranged from 0.4 to 790 ppb in fish, with the major components identified as 2,3',4,4',5-penta-(118) and 2,3,3',4,4'-pentachlorobiphenyls (105). When concentrations were converted to 2,3,7,8-TCDD picogram equivalents, 99% of the equivalents were derived from three congeners (77, 105, and 126), 3,3',4,4',5-pentachlorobiphenyl (126) accounting for approximately 80% of the activity. At Troy pg/g TCDD equivalents derived from PCB were approximately 3000, whereas the actual 2,3,7,8-TCDD concentration was only 20 pg/g; hence, accurate coplanar PCB measurement is important.     

Inhibition of GABA-gated chloride channel function by arachidonic acid

The effects of arachidonic acid and its metabolites on gamma-aminobutyric acid (GABAA) receptor function were determined in rat cerebral cortical synaptoneurosomes. Incubation of synaptoneurosomes with phospholipase A2 decreased muscimol-induced 36Cl- uptake. Arachidonic acid, the major unsaturated fatty acid released by phospholipase A2, also inhibited muscimol-induced 36Cl uptake. Similar inhibition was obtained with other unsaturated fatty acids (docosahexaenoic, oleic) but not with saturated fatty acids (stearic, palmitic). The effect of arachidonic acid on muscimol responses was inhibited by bovine serum albumin (BSA), and BSA enhanced muscimol responses directly, indicating the generation of endogenous arachidonic acid in the synaptoneurosome preparation. The generation of endogenous arachidonic acid was also indicated by the ability of 2 inhibitors of arachidonic acid metabolism, indomethacin and nordihydroguaiaretic acid (NDGA), to inhibit muscimol-induced 36Cl uptake. We conclude that arachidonic acid probably has both direct and indirect actions on muscimol responses since both enzyme inhibitors inhibited muscimol responses but did not prevent the effect of exogenously added arachidonic acid. In additional experiments, arachidonic acid metabolites generated by cyclooxygenase, prostaglandins D2, E2 and F2 alpha, each decreased muscimol responses; prostaglandins F2 alpha was the most potent inhibitor. Since the unsaturated fatty acids and their metabolites are most susceptible to peroxidation, a generating system of superoxide radicals was tested on muscimol responses. A combination of xanthine and xanthine oxidase inhibited muscimol-induced 36Cl uptake in a concentration-dependent manner. We propose that the inhibition of GABAA neurotransmission by arachidonic acid and its metabolites can lead to increased neuronal excitability. This mechanism may play an important role in the development of neuronal damage following seizures or cerebral ischemia.     

PsD007对四株NPC细胞放射敏感性的影响

采用ＭＴＴ方法观察癌光啉结合＾６０Ｃｏγ射线放射对四株人鼻咽癌细胞体外放射增敏作用，结果表明在一定的ＰｓＤ００７浓度范围内，随ＰｓＤ００７浓度的升高，放射对细胞的杀灭作用明显增强，当浓度分别为１．２５，６．２５，１２．５，２５和５０μｇ／ｍｌ时，对四株细胞杀灭增加倍数分别为１．０１－１．０６，１．１５－１．２９，１．２８－１．５９，１．７９－３．１８，２．８６－５．５５；放射量效存活曲线按多靶单击     

低温保存同种心脏瓣膜活性及临床应用的研究

取正常成人心脏瓣膜３６个，置于低浓度广谱抗生素的营养液（ＲＰ－ＭＩ１６４０细胞培养液）中灭菌４８ｈ，－８０℃冰箱初冻，置于液氮中长期保存。灭菌前后瓣膜细菌培养阴性率分别为９４．３％和１００％，解冻后经光镜、电镜检查证实瓣组织细胞结构正常，组织培养葡萄糖消耗率测定示瓣组织存活良好。临床同种心脏瓣膜原位移植３例，随访６～３０个月，瓣功能良好     

有效控制与控制不佳的MRI阴性的GTCS病人发作间期SPECT对照研究

目的:利用单光子发射计算机断层摄影(SPECT)半定量分析有效控制与控制不良的MRI阴性的全面性强直阵挛发作癫(GTCS)病人的局部脑血流差异,探讨脑血流灌注与其预后的关系.材料和方法:对29例有效控制的和12例控制不佳的MRI阴性的GTCS病人进行发作间期99mTc-ECD-SPECT脑血灌流显像,10例年龄匹配的健康人作对照,用感兴趣区(ROI)的不对称指数(%AI)进行半定量分析.将SPECT分析结果与病人的临床表现与EEG相比较.结果:①控制不佳组与有效控制组在丘脑和基底节区的%AI存在显著性差异(P<0.05);②控制不佳组SPECT脑显像的异常率(83.3%,10/12)明显高于有效控制组的异常率(17.2%,5/29),两组具有显著性差异(P<0.01);而两组病人的EEG异常率分别为58.3%、44.8%(7/12、13/29),无显著性差异(P>0.05).结论:控制不佳的MRI阴性的GTCS病人往往存在发作间期的低血流灌注脑区,提示癫的难治性;而控制良好的病人多无明显异常发现,可能预后较好.     

新型胫骨髓内钉的研制与生物力学研究

目的　研制新型胫骨串孔型髓内钉并对其进行生物力学研究。方法　用TAMZ合金制造远端锁孔由一个三个同样直径的串孔所替代的 9根新型胫骨髓内钉。将髓内钉安装在自行设计的夹具中 ,先将 3根新钉进行静态垂直压缩实验 ,根据静态实验结果 ,分别测试 6根新钉的动态疲劳强度。结果　新钉的静态压缩破坏载荷为 2 1 33N ,是人平均体重的 3倍多 ;通过 5 0万次压缩循环的条件疲劳强度为 1 2 0 0N ,约是人体重的 2倍。结论　新钉不仅能够方便临床使用 ,而且拥有较好的力学特性     

脑干、三叉神经及大脑动脉环的可视化研究

目的 建立人体脑干、三叉神经及大脑动脉环的可视化数字模型。方法 采用首例中国数字化可视人体数据集，在SGI工作站上对脑干及其周围毗邻结构进行计算机三维重建并立体显示。结果 获得人体脑干、三叉神经及大脑动脉环等器官组织的三维重建结构，可对其进行任意径线和角度的适时三维测量。结论 首例中国数字化可视人体数据集能够提供完整而精确的解剖断面数据，脑干及其毗邻的三叉神经、大脑动脉环的可视化模型准确反映出该区域复杂的解剖学结构特点及其相邻器官间的空间毗邻关系，可为该区域的疾病的影像诊断和外科治疗提供形态学依据。     

膝前框形钢丝内固定治疗髌骨骨折

目的　总结采用钢丝环扎 +膝前方框形张力带钢丝内固定法治疗髌骨骨折的经验和临床效果。方法　对 3 5例髌骨骨折应用此方法治疗 ,其中男性 2 4例 ,女性 11例 ,3 0例获得 3～ 2 4个月随访。结果　优 19例 ,良 10例 ,可1例 ,优良率 96 7%。术后未出现骨折再移位 ,无伤口感染。愈合时间 6～ 12周。结论　该方法符合生物力学原理 ,操作简便 ,适应证广 ,能早期关节活动 ,是治疗髌骨骨折的理想方法之一。     

前颌中缝牵张修复牙槽裂的实验研究

目的　探索用缝牵张成骨技术以组织再生的原理修复牙槽裂。方法　采用犬牙槽裂模型 ,牙槽裂形成术后 2周 ,于前颌中缝处安置缝牵张器 ,外张力 2 0 0g。牵张 2～ 3周 ,裂隙侧的前颌骨向侧方移动贴紧远中裂缘 ,用局部黏骨膜瓣修复牙槽裂隙。保持 2周后去除缝牵张器。临床观察、连续X线、头颅干骨和组织学检查评价治疗结果。结果　所有对照动物形成规则的牙槽裂 ,无自发骨性愈合。前颌中缝牵张后 ,裂隙侧前颌缓慢向裂侧上颌靠拢 ,2～ 3周与远中裂缘密切贴合。X线片示前颌中缝呈现由窄渐宽的三角形 ,三角形的尖端指向后方 ,三角区域的骨密度逐渐增加。骨膜成形术后 3个月 ,原牙槽嵴缺损处骨质连续性完全恢复 ,且牙槽骨段在三维方向上均与对侧相同。前颌中缝恢复正常直线形态。结论　该牙槽裂模型稳定性和重复性好 ;前颌中缝牵张诱导缝区新骨形成 ,一侧前颌向裂隙移位和局部骨膜成形可达到完善的牙槽裂修复。     

基于美军二战海战减员数据的校正

目的：通过对二战减员数据的校正，为下一步建立海战减员预计模型提供数据支持．方法：选取美军在二战太平洋海战中的减员数据作为研究的基本资料，通过专家咨询法(Delph method)对其进行校正，所有结果都对其进行了t检验．结果：水面舰艇遭受炸弹、舰炮及航空火炮、短程导弹、鱼雷和水雷的攻击时减员将减少，遭受中程导弹攻击时减员将会增加．结论：该校正结果可作为研究未来海战卫生减员预计的基本依据之一．