手掌部浅血管神经层与屈肌支持带关系的观测

目的：为腕管松解术及掌中间隙引流术提供解剖学基础。方法：１８例（男１２、女６）３６侧成人固定上肢标本上对手掌部屈肌支持带、正中神经、尺神经在胱掌部分支点和掌浅弓最高点与屈肌支撑带下缘的距离以及足动脉终末支与正中神经间距观察。结果：正中神经掌部分支点距屈肌支持下缘９±３ｍｍ。尺神经掌部分支点距屈肌支持带下缘５±２ｍｍ。正中神经于与尺动脉终末间距为１０±２ｍｍ。结论：在手掌部裳托肌腱与第三指蹼尺侧缘     

口腔修复中高熔铸件浇铸不全的原因浅析及预防

目的:探讨高熔铸件浇铸不全的可能原因。方法:通过对临床85件可摘铸件缺损的初浅分析,总结出浇铸不全的可能原因。结果:高熔铸件浇铸不全的原因有以下7个方面:①铸金量不足;②熔金温度过低;③离心力不够;④铸道布局不当;⑤铸件过薄;⑥高温包埋料透气性差;⑦铸圈温度下降。结论:通过查找原因,总结出预防的方法,对提高高熔铸件修复体的质量有一定的作用。     

计算机在固定床传热参数测定中的应用

开发了固定床传热参数测定的通用计算机处理系统,并给出了国产新型环柱状醋酸乙烯合成催化床的径向导热系数及壁给热系数的测定实例。     

Long-lasting increase in the set point for cocaine self-administration after escalation in rats

Rationale: When access time to a continuous schedule of drug self-administration is restricted, animals tend to limit intake to a certain level over time and across doses. This observation suggests an endogenous constraint or set point that determines the individual’s preferred level of pharmacological effects. Objectives: To assess whether the transition to increased levels of drug intake is associated with a change in set point. Methods: Two groups of rats were trained on a 1-h continuous schedule of cocaine self-administration (250 μg/injection), after which access to cocaine was increased to 6 h in one group (Long Access or LgA rats) or kept to 1 h in the other group (Short Access or ShA rats). After 22 sessions on this regimen, different doses of cocaine were tested (31.25, 62.5, 125, and 250 μg/injection). For each dose, the post-response time-out period was reduced to 4 s to reduce any temporal limitations on self-injections and subjects were tested several times. Results: In LgA rats, the first hour intake escalated over time and eventually reached a level 200% greater than that of ShA rats. Though all rats maintained relatively constant intake across doses, LgA rats took nearly two times as much cocaine than ShA rats. When access to cocaine for LgA rats was reduced to 1 h, intake returned very slowly toward pre-escalation levels but was still elevated even after 2 months of reduced availability. Conclusions: These data suggest that the transition to escalated levels of intake is associated with a long-lasting change in cocaine set point. Received: 12 February 1999 / Final version: 21 May 1999     

Pharmacokinetics of methotrexate in leukemia cells: Effect of dose and mode of injection

A lumped compartmental model has been derived to predict methotrexate concentration as a function of time for L1210 cells in BD2F ₁ female mice at doses ranging from 3 mg/kg to 400 mg/kg. Using standard methods of parameter estimation as well as experimental determinations, an integrated approach was derived to account for the differences between the subcutaneous (s.c.) and intraperitoneal (i.p.) modes of injection. It was found that a single generalized forcing function can be used to fit plasma concentration after s.c. injection for all doses. Adequate fits (average error<20% while the standard deviation of experimental determinations was±22%) of L1210 cell data after s.c. injection were obtained. The best results were for a maximum facilitated influx constant V_max of 0.424 g/min/ml, a Michaelis influx constant K_m of 1,42 g/ml, and a first-order efflux constant of 0.047 min^–1.The model simulations were not sensitive to V_max, K_m,and so long as the ratio V_max/was approximately 9g/ml. The values of V _max ,K _m ,and which were obtained from our analysis of the in vivodata can be explained on the basis of previously performed in vitroexperiments. The parameters obtained from modeling the s.c. data were then applied for i.p. injection data. The resulting fits were adequate (average error<20% while the standard deviation of experimental determinations was±22%). A single generalized forcing function for drug concentration in the peritoneal cavity after i.p. injection for all doses was derived. The application of these results enables the prediction of methotrexate concentration in neoplastic cells at other doses after either s.c. or i.p. injection.     

Progressive-ratio performance maintained by drug infusions: Comparison of cocaine,diethylpropion, chlorphentermine,and fenfluramine

Cocaine, diethylpropion, chlorphentermine, and fenfluramine were compared on a drug-maintained progressive-ratio procedure in baboons. Intravenous infusions of drug were contingent on completion of a fixed-ratio response requirement (fixed number of lever-press responses) with a 3-h time-out period following each infusion. Prior to testing each dose of drug, stable self-infusion performance was first established with 0.4 mg/kg cocaine when the fixed-ratio requirement was 160. Subsequently, a test dose of drug was substituted for the standard dose of cocaine. If the dose of drug maintained a criterion level of self-infusion performance (six or more infusions per day for 2 days), the ratio requirement was systematically increased every day until the breaking point at which the self-infusion performance fell below a criterion level (one or zero infusionsper day). Fenfluramine did not maintain criterion self-infusion performance at any dose tested (0.02–5.0 mg/kg). The dose ranges of the other drugs that maintained maximum breaking points were 1.0–5.6 mg/kg for chlorphentermine, 1.0–3.0 mg/kg for diethylpropion, and 0.1–0.4 mg/kg for cocaine. Within-animal comparison of the maximum breaking points indicated that cocaine maintained the highest breaking points, followed in order by diethylpropion, chlorphentermine, and fenfluramine. The rank ordering of these drugs with the breaking point measure corresponds well with both the results of other animal experiments on measurement of reinforcing efficacy of these drugs and with the clinical information about the human subjective effects and abuse of these drugs.     

The differential effects of haloperidol and methamphetamine on time estimation in the rat

Forty rats were trained to make a left lever response if a signal (white noise) was 2.5s and to make a right lever response if the signal was 6.3s. When seven intermediate signal durations, to which responses were not reinforced, were randomly interspersed the probability of a right-lever (long) response increased as a function of signal duration. Methamphetamine shifted this psychometric function leftward and decreased its slope: haloperidol also decreased the slope but shifted the function rightward. A combination of haloperidol and methamphetamine led to a function similar to the saline control function. The leftward shift probably reflects an increase in the speed of an internal clock, and the rightward shift probably reflects a decrease in its speed. Since methamphetamine releases several catecholamines, including dopamine, and haloperidol blocks dopamine receptors, it is plausible that the horizontal location of the psychometric function (the speed of the clock) is related to the effective level of dopamine.     

电针“曲泉”穴对小鼠胆汁分泌的影响

本实验用具备胆瘘的大鼠颈静脉恒速灌注肝胆酸钠10μmol/(100g·h)维持胆汁酸池恒定条件下,观察电针“曲泉”穴对肝胆汁分泌的影响及与受体的炎系。结果表明:电针“曲泉”穴,胆汁流量、胆汁K~+、Na~+、Cl~-、HCO_3~-排出量均显著增加,(P<0.01),但不影响胆酸的排出量。说明电针“曲泉”穴有利胆作用,所刺激肝胆汁本属不依赖胆汁酸部分。在本实验条件下,静脉给予阿托品(0.2mg/kg),酚妥拉明2.5mg/(kg·h))、心得安(5mg/kg)对胆汁分泌无显著影响,但阿托品有加强其利胆效应的倾向(P>0.05),而心得安则完全抑制其效应(P<0.01)。结果表明:“曲泉”穴的利胆效应与β受体有关,与α受体关系不大,并提示M受体或阿托品及体液因素如促胰液素,胰高血糖素等亦可参与“曲泉”穴的利胆机制。     

Lithium effects on time estimation and mood in manic-melancholic patients. A study of diurnal variations

Behavioural measurements of time experience and phenomenological self-ratings of mood-variations (Beecher's Mood Scale) have been carried out at night and on the following morning in a group of lithium-treated patients, in a group of psychiatric patients not given lithium, and in an untreated group of healthy subjects. In all the groups investigated the internal "clock" was slower in the morning than in the night. The results indicated that the internal "clock" in lithium-treated patients was slower than in the two other groups, but only at night. Mood variations from night ot morning were observed in all three groups. The group of lithium-treated patients had fewer complaints as to self-report of mood-variations compared with the other groups.     

Objective assessment of auditory thresholds in noise‐induced hearing loss using steady‐state evoked potentials

Objective assessment of auditory thresholds in noise‐induced hearing loss using steady‐state evoked potentials The purpose of this study is to evaluate whether steady‐state evoked potential (SSEP) can be used for objective estimation of auditory thresholds in patients with noise‐induced hearing loss (NIHL). Eleven subjects (22 ears) with a characteristic audiometric notch between 3000 and 6000 Hz participated in this study. Both pure‐tone thresholds and SSEP thresholds were obtained for each ear of all subjects. The correlation of SSEP thresholds and pure‐tone thresholds was assessed. The results show that SSEP thresholds predicted pure‐tone thresholds with correlation coefficients (r) of 0.86, 0.92, 0.94 and 0.95 at 500, 1000, 2000 and 4000 Hz respectively. Typically, the SSEP thresholds overestimate the pure‐tone thresholds by 10–20 dB, but they closely reflect the configuration of the audiogram. The strength of the relationship between SSEP and pure‐tone thresholds increased with increasing frequency and increasing degree of hearing loss. In conclusion, SSEP can be used as a reliable and objective tool to assess auditory thresholds in patients with noise‐induced hearing loss with high‐frequency dips.