Suppression of presynaptic calcium currents by hypoxia in hippocampal tissue slices.

We tested the hypothesis that suppression of inward calcium current in presynaptic terminals is the cause of failure of synaptic transmission early during cerebral hypoxia. Postsynaptic responses in CA1 zone of hippocampal tissue slices were blocked either by the combined administration of 6,7-dinitroquinoxaline-2,3-dione (DNQX) and 3-((+-)-2-carboxypiperazine-4-yl)-propyl-1-phosphonic acid (CPP) or by lowering extracellular calcium concentration ([Ca2+]o). Repetitive orthodromic activation of central neurons caused transient decrease of [Ca2+]o (measured by ion selective microelectrodes) in neuropil, attributable to influx of Ca2+ in presynaptic terminals. Presynaptic [Ca2+]o responses were rapidly and reversibly suppressed when oxygen was withdrawn from hippocampal tissue slices. The 'resting' baseline level of [Ca2+]o declined at first gradually, then precipitously as in spreading depression (SD). Presynaptic volleys during high frequency train stimulation were also depressed somewhat before SD began. We conclude that (1) presynaptic Ca2+ currents fail during hypoxia, perhaps because 'resting' intracellular free Ca2+ activity is increased and, in part, also because of partial failure of presynaptic impulse conduction; (2) the influx of Ca2+ into brain cells in hypoxic spreading depression is not mediated by glutamate/aspartate dependent channels.     

京剧器乐的听力损伤（附55例调查报告）

本文对从事京剧打击乐的55人（110耳）进行了听力调查及动态观察。利用图表进行对比分析，发现110耳中高频听力损伤89耳，占81％；语频听力损伤32耳，占29.1%；其中伴有高频耳鸣78耳，占70．9％。动态观察30人（60耳），均为永久性听阈阈移。高频听力损伤最早出现的频率是4kHz，并见典型“V”谷，符合噪声性聋的诊断。     

恒猴精索内注射长效局麻药后对睾丸和附睾的影响

在13只恒河猴精索内注射长效局麻药后,睾丸发生明显变化;而且给药剂量不同,睾丸曲精小管改变的程度和恢复正常的时间亦不同。睾丸间质细胞无明显变化;睾酮分泌不减少,无毒性反应。对临床男性节育应用及生殖生理研究均具有意义。     

Renal tubular epithelial cells express osteonectin in vivo and in vitro.

Osteonectin (SPARC, culture shock protein, BM-40) is a widely distributed glycoprotein which binds calcium and several extracellular matrix proteins, including interstitial collagens and thrombospondin, but whose physiologic role remains undefined. In the present studies, we have demonstrated that immunoreactive osteonectin is present in the distal cortical tubule and medullary tubules of murine kidney. We surveyed the renal epithelial cell lines LLC-PK1, MDCK, and OK for the expression of mRNA encoding osteonectin. We found that osteonectin mRNA is expressed by LLC-PK1 and OK cells but not by MDCK cells, as well as by adult kidney from several species. Calcitonin and vasopressin, agents which increase cAMP in these cells, were found to decrease steady-state osteonectin mRNA concentrations. We found that LLC-PK1 cells produced osteonectin protein, that the protein was localized to intracellular granules, and that the protein bound hydroxyapatite in vitro. Pulse-chase analysis revealed that osteonectin was secreted from the cell layer to the medium after a lag time of four to six hours and was secreted preferentially from the basolateral domain of the cell. The preferential secretion of the calcium-binding protein osteonectin from the renal epithelial cell is consistent with several possible functions, including a structural extracellular matrix protein, a participant in transepithelial ion transport, and an inhibitor of extracellular calcification.     

大剂量卡铂化疗的药物毒性观察

6例肺癌患者接受了大剂量卡铂并自体骨髓移植治疗 ,卡铂剂量从 5 60～ 1375 mg/ m2 ,5例加用 VP～ 1630 0 mg,1例并用 MMC6mg和 VCR2 mg;主要毒性反应为白细胞、中性粒细胞、血小板减少和脱发 ( WHO毒性反应 ～ 级 )其次是贫血、皮肤粘膜出血、呕吐和可逆性肝功能损害 ,口腔粘膜溃疡及轻度发烧各 2例 ,一过性蛋白尿、室上性心动过速和便秘各 1例 ,尿素氮和肌酐未见升高 ;全部患者骨髓均获解救 ,从自体骨髓回输到骨髓造血功能重建成功平均 2 6.67( 17～ 32 )天     

Laparoscopic nephrectomy in a porcine model.

Laparoscopic nephrectomy was performed in 15 male pigs, the procedure was successful in 14. Extraction of the intact kidney through a 5-cm lower abdomen incision was done in 7 animals; complete destruction and evacuation of the kidney was accomplished by a round-knife suction device through a 1-cm port in another 7 pigs. Grossly, the specimen consisted of sausage-like tubular renal tissue and a small amount of tissue debris. Pathology revealed that the glomerular and tubular structures were well preserved, no interstitial hematoma could be found. Four ports were usually used, one 1-cm umbilical camera port, one 0.5-cm port for ureter traction, and two 1-cm working ports along the midclavicular line. All the pigs recovered uneventfully. The average operation time was 3 h 20 min. The application of endo-GIA (United States Surgical Corporation) for renal hilum reduced the operative time to 2 h 20 min. Complications included renal vein tear during endoclip application and cutting in the first case, mild subcutaneous emphysema in 2 cases. This first pig received exploratory laparotomy for the repair and ligation of the renal vein. No more major complications occurred with increasing experience. From this porcine experiment, we conclude that the combination of laparoscopy, a tissue destroyer and an endobag for the entrapment of kidney seem to be a promising technique for clinical nephrectomy.     

Overgrowth of a costochondral graft in reconstruction of the temporomandibular joint.

We report the case of a 3-year-old girl with temporomandibular ankylosis, which was treated with a costochondral graft and required two further resections because the grafted tissue had overgrown.