Anaesthetic agents decrease the activity of nitric oxide synthase from human polymorphonuclear leucocytes

Nitric oxide (NO) inhibitors reduce the threshold for anaesthesia. We have investigated the action of anaesthetic agents on human nitric oxide synthase (NOS) activity. Thiopentone reduced mean NOS activity to 36.6 (SD 8.9) % of control at 100 mumol litre-1 (P < 0.001) and 50.9 (20.3) % at 1 mmol litre-1 (P < 0.05). Ketamine showed similar effects, with activity reduced to 67.0 (17.6) % (P < 0.05) and 57.7 (8.5) % (P < 0.001) at 100 mumol litre-1 and 1 mmol litre-1, respectively. Etomidate 100 mumol litre-1 did not significantly alter activity (88.2 (8.1) %) but 1 mmol litre-1 did (60.6 (10.4) %, P < 0.005). Halothane also caused a significant decrease in NOS activity at all concentrations. This effect was specific as other enzymes were unaffected. We conclude that anaesthetic agents have a profound effect on NOS activity and as inhibition of NO release augments anaesthesia, we suggest that this may play a role in the mechanism of anaesthesia in humans.      

Nine Years of the Freebase Cocaine Epidemic in the Bahamas

Nine years after the beginning of the epidemic of freebase (crack) cocaine abuse in the Bahamas, this historical study was done to characterize the natural course of the epidemic and to estimate the effectiveness of control measures. The authors' data include the incidence of new cases at the only psychiatric hospital in the Bahamas and at the primary community psychiatric clinic in the nation. The Bahamian response included 1) demand reduction, 2) supply reduction, and 3) reduction of money laundering. The annual number of new cases of crack abuse presenting for treatment declined from 1987 to mid-1991 in both facilities, but in 1992 it began rising again in the inpatient setting only. The changes in recent years have been accompanied by an increase in violent crimes against persons, especially robberies. (American Journal on Addictions 1994; 3:14–24)     

Development of the vestibular and auditory system of the northern native cat,Dasyurus hallucatus

The developing vestibular and auditory system of the native cat Dasyurus hallucatus was examined from birth to day 55 postpartum to determine when the six sensory regions had an adult structure. The utricle, a sensory epithelium with an overlying discrete population of otoliths, was present in the newborn native cat. The saccule, which has a similar structure to the utricle, and the three crista ampullaris of the semicircular canals, were present by day 21 postpartum. The organ of Corti was formed by day 50 and the external ear duct was patent by day 55 postpartum. Hair is first seen on the native cat by day 45 when the young first leave the pouch. They are left in the nest and travel on the back of the lactating mother until about day 80. The eyes open on approximately day 75. Thus, the native cat has fully functional visual, auditory, and vestibular systems when the juvenile leaves the nest. © 1992 Wiley-Liss, Inc.     

The effects of three nebulized osmotic agents in the dry larynx.

PURPOSE: This investigation examined the effects of nebulized hypertonic saline, isotonic saline (IS), and sterile (hypotonic) water on phonation threshold pressure (PTP) and self-perceived phonatory effort (PPE) following a surface laryngeal dehydration challenge. METHOD: In a double-blind, randomized experimental trial, 60 vocally healthy women (n = 15 per group) underwent a laryngeal desiccation challenge involving oral breathing for 15 min using medical-grade dry air (RH<1%). Three of the four groups then received nebulized isotonic saline (0.9% NaCl), hypertonic saline (7% NaCl), or sterile (hypotonic) water, respectively; the 4th group served as a nontreatment control. PTP and PPE were estimated for high-pitched productions at baseline, immediately postdesiccation, and at 5, 20, 35, and 50 min postnebulization. RESULTS: PTP increased significantly for all groups following the desiccation challenge. PTP values were, on average, 0.5 cm H(2)O greater immediately postdesiccation versus baseline. In contrast, PTP values did not change significantly following the administration of nebulized treatments, although a temporary trend toward a reduction in PTP was observed for the IS group. Unexpectedly, PPE ratings decreased significantly after the desiccation challenge. In general, PPE ratings were poorly correlated with PTP measures. CONCLUSION: A laryngeal desiccation challenge (i.e., temporary exposure to extremely low relative humidity while breathing transorally) significantly increased PTP. Although interesting trends emerged, none of the nebulized treatments significantly enhanced recovery from the negative effects of desiccation on PTP. In light of very low correlations between PTP and PPE, serious questions are raised regarding presumed associations between these measures.     

小型猪在异种移植中的应用前景

目的 建立狂犬病病毒感染动物疾病模型.方法 狂犬病病毒CVS-B2C毒株以10LD50剂量腿部肌肉注射接种4～6周龄的BALB/c小鼠,0.2 mL/只,于BSL2实验室负压IVC设备内饲养观察,并对其模型进行评价.结果 小鼠接种狂犬病病毒后一周左右就出现临床症状,表现为饮食量下降,毛皮慢慢失去原先的光泽,体重下降,并出现麻痹等症状,进而死亡,部分小鼠出现躁狂的症状或抽搐性和强直性痉挛,而对照组小鼠则表现正常.DFA法检测结果:感染上狂犬病毒的小鼠脑组织涂片中出现特异性荧光抗体染色反应,而对照组动物的小鼠脑组织涂片未出现荧光抗体染色反应.RT-PCR法检测结果:从感染小鼠脑组织标本中提取病毒RNA,引物扩增出的目的 基因片段,大小约为1kb,为N蛋白.免疫组化法检测结果:感染狂犬病毒的小鼠脑切片显示出棕色阳性颗粒,对照组小鼠脑切片染色阴性.病理检测结果:HE染色可见感染小鼠脑组织炎性细胞浸润.神经细胞胞质内出现内基体以及神经细胞退行性病变.结论 成功的复制出小鼠狂犬病病毒感染模型,为研究和控制狂犬病奠定了基础.