Flavor preference conditioning by oral self-administration of ethanol

 Oral self-administration and operant tasks have been used successfully to confirm ethanol′s positive reinforcing effects in rats. However, in flavor conditioning tasks, ethanol is typically found to have aversive effects. The present studies explored this apparent paradox by examining the change in value of a flavor paired with orally self-administered ethanol in two different limited-access procedures. Rats were food-deprived and trained to drink (experiment 1) or to barpress for (experiment 2) 10% (v/v) ethanol during daily 30-min sessions using prandial initiation techniques. All rats were then exposed to a differential flavor conditioning procedure in which banana or almond extract was added to the drinking solution. One flavor (counterbalanced) was always mixed with ethanol (CS+), whereas the other flavor was mixed with water (CS–). By the end of conditioning, rats in both experiments drank more flavored ethanol than flavored water, confirming ethanol’s efficacy as a reinforcer. Moreover, barpress rates for CS+ exceeded those for CS– in the operant task. Ethanol doses self-administered in final sessions averaged about 1 g/kg. The effect of the flavor-ethanol contingency was assessed in preference tests that offered a choice between the two flavor solutions without ethanol. In both experiments, subjects developed a preference for the flavor that had been paired with ethanol. Thus, the outcome of flavor conditioning was consistent with that of the oral self-administration tasks in providing evidence of ethanol’s rewarding effects. These experiments confirm and extend previous studies showing that flavor aversion is not the inevitable result of flavor-ethanol association in rats. It seems likely that ethanol’s nutrient and pharmacological effects both contributed to the development of conditioned flavor preference. Received: 15 February 1997 / Final version: 11 June 1997     

西宁地区冠心病113例临床分析

本文通过西宁地区１１３例住院冠心病人的临床分析，认为西宁地区冠心病患病率低，患者年龄大，男性患病率高于女性，而且绝经期后的高龄女性患者患病率仍然远比男性低，这些与低海拔地区不同。而冠心病各型的分布、临床症状、病死率等与低海拔地区相似。     

Catastrophic failure of modular Zirconia—Ceramic femoral head components after total hip arthroplasty

Catastrophic failure of two zirconia—ceramic modular femoral heads occurred, despite the theoretical improved toughness of zirconia—ceramic relative to alumina—ceramic. This experience led the authors to return to cobalt—chromium as the metal of choice for articulation against polyethylene in total hip arthroplasty.     

Seasonal covariation of the circadian phases of rectal temperature and slow wave sleep onset

There is a scarcity of well-controlled studies of the seasonal variation in circadian rhythmicity. In the present study, the circadian phase of rectal temperature and the onset of slow wave sleep were studied in a series of twelve 24-h experiments, one each month of the year, for six healthy subjects under controlled conditions in a climatic chamber. In winter, as compared with summer, the average circadian rhythm of rectal temperature was phase delayed by 45 min, and the average onset of slow wave sleep was phase delayed by 40 min. The temporal relationship between the circadian phase of rectal temperature and the timing of slow wave sleep was maintained throughout the year. Habitual rising and retiring times covaried as well. Furthermore, the circadian rhythm of rectal temperature followed the timing of the photoperiod across the year, but had a much smaller range of seasonal variation. Apparently, the seasonal variation in the photoperiodic zeitgeber is largely compensated for by the stabilizing influence of secondary zeitgebers. However, in healthy subjects some effect of photoperiodic variation can still be observed.     

紫外分光光度法测定SOD活性的应用及其意义

本文对SOD的紫外分光光度法测定进行了实用性研究。结果表明,本文方法具有用血量少,重现性好,快速、灵敏,试剂廉价等优点。西宁地区与平原地区人群的比较测定显示,前者SOD活性明显高于后者(P<0.01)。     

下蹲运动与高眼压关系及其动态观察

观察１８例３２眼下蹲运动与高眼压的关系，分为下蹲１２０次，１００次及８０次三且，每组分别观察１０眼、１１眼及１１眼，结果各组运动后眼压均见下降，平均为１．０２７±０．４８６ｋＰａ，１．３５５±０．７７０ｋＰａ及１．３２５±０．４２２ｋＰａ，运动前后有非常显著性差异，但各组之间差异不显著。同时观察３小时内眼压动态变化，下蹲１２０次组眼压下降维持时间最长，在运动后３小时与运动前眼压比较及与其余两组第３     

High frequency jet ventilation for microlaryngeal laser surgery

The use of a triple lumen central venous catheter, which can be shielded from laser irradiation by metal tape, as a conduit for high frequency jet ventilation in six children, is described. The problems of anaesthesia for laryngeal laser surgery and the advantages of the technique described in this paper are discussed.     

小鼠暴露在不同海拔梯度下脑含水量改变及其与脑水肿的关系

观察了小鼠暴露在不同海拔梯度下脑含水量改变及其与脑水肿的关系。实验结果表明，小鼠由低海拔区快速进入高海拔区后脑组织的湿干比值和含水量均有增高（Ｐ＜００１），以进入高海拔区后的第７ｄ为最高峰。组织学观察表明，此时脑神经细胞肿胀，胞浆内有空泡变性，胶质细胞和微血管周围有明显空晕。以上结果揭示，由低海拔区快速进入高海拔区后可致脑水肿形成。