Effect of Carbon Dioxide on Cochlear Blood Flow in Guinea Pigs

The influence of carbon dioxide (CO2) on cochlear blood flow (CBF), blood pressure (SBP) and skin blood flow (SBF) was studied in anaesthetized guinea pigs. A transient acute respiratory acidosis was produced by inhalation of CO2 and oxygen (O2) gas mixtures. The blood flows were measured by laser Doppler flowmetry (LDF). High CO2 increased CBF and SBP, and decreased SBF in a dose-dependent manner. The responses of CBF, SBP and SBF to high CO2 were reversible. Our results indicate that high CO2 (and low pH) dilates the smooth muscle of the blood vessels, resulting in an increase in CBF. CO2 also activates the sympathetic nervous system in the whole body, producing an increase in SBP. The distribution of alpha-adrenergic fibres/receptors is abundant in skin and scarce in the cochlea. The constrictive effect on blood vessels is much greater in the skin than in the cochlea, thus our results showed a decrease in SBF during stimulation with higher CO2.     

医护人员手卫生执行情况及相关影响因素分析

目的:了解在临床工作的医护人员对洗手认识及行为的情况,并探讨分析相关影响因素.方法:以问卷形式调查医护人员对主动洗手相关影响因素的认识.配合暗中观察其洗手行为.结果:医护人员执行平均洗手率为37.1%.快速手消毒剂(ABHR)的洗手率仅为3.1%;医护人员手卫生执行率与其洗手意识、是否提供和使用快速手消毒剂以及洗手设施是否完善相关:洗手率较高的医护人员意识较强、且较多使用快速手消毒剂(P<0.05);接触患者前和接触患者之间洗手率与有无洗手槽及离病房远近、是否提供擦手纸巾、有无热水等设施有明显相关性(P<0.05),接触患者后洗手率与此却无统计学意义上的相关性(P>0.05);医护人员手卫生执行与病房内是否提供快速手消毒剂也无统计学意义上的相关性.结论:应提高医护人员对洗手重要性的再认识,有针对性改善病房内洗手条件,提高医护人员对快速手消毒剂的接受度,从而真正有效地提高医护人员的洗手依从性.     

Nicotine dependence and smoking cessation after hospital discharge among inpatients with coronary heart attacks

This study focuses on the predictability of two alternative questionnaires for nicotine dependence, i.e., the Fagerstrom Tolerance Questionnaire (FTQ) and the Tobacco Dependence Screener (TDS), each of which represents a different aspect of dependence, among patients with coronary heart disease (CHD). Twenty-nine male inpatients that had been newly diagnosed as CHD were followed up for 30 weeks after hospital discharge. The baseline information included age, number of cigarettes per day, years of smoking, disease type (angina pectoris [AP] or acute myocardial infarction [AMI), whether they had received a briefing on smoking cessation, the FTQ, and the TDS. At 30 weeks after hospital discharge, 19 (66%) were abstainers. The group with a high TDS score (of 6 or greater) was significantly less likely to quit smoking than the group with a low TDS score (p=0.046). The FTQ score was not significantly different between the abstainers and non-abstainers. The subjects with AP were significantly less likely to quit smoking than those with AMI (p=0.021). Multiple logistic regression analysis showed that belonging to the high-TDS group and being diagnosed as AP were significantly associated with failure in smoking cessation (p<0.05). The present study suggests that the TDS may have higher predictability than the FTQ concerning smoking cessation among CHD inpatients.     

Decision-making and addiction (part II): myopia for the future or hypersensitivity to reward?

On a decision-making instrument known as the "gambling task" (GT), a subgroup of substance dependent individuals (SDI) opted for choices that yield high immediate gains in spite of higher future losses. This resembles the behavior of patients with ventromedial (VM) prefrontal cortex lesions. In this study, we addressed the possibility that hypersensitivity to reward may account for the "myopia" for the future in this subgroup of SDI. We used a variant version of the GT, in which the good decks yielded high immediate punishment but higher delayed reward. The bad decks yielded low immediate punishment and lower delayed reward. We measured the skin conductance response (SCR) of subjects after receiving reward (reward SCR) and during their pondering from which deck to choose (anticipatory SCR). A subgroup of SDI who was not impaired on the original GT performed normally on the variant GT. The subgroup of SDI who was impaired on the original GT showed two levels of performance on the variant GT. One subgroup (36% of the sample) performed poorly on the variant GT, and showed similar behavioral and physiological impairments to VM patients. The other subgroup of SDI (64% of the sample) performed normally on the variant task, but had abnormally large physiological responses to reward, i.e. large SCR after receiving reward (reward SCR) and large SCR in anticipation of outcomes that yield large reward. Thus, the combined cognitive and physiological approach of assessing decision-making characterizes three sub-populations of SDI. One sub-population is without impairments that can be detected by any measure of the GT paradigm. Another sub-population is similar to VM patients in that they are insensitive to the future, both positive and negative. A third sub-population is hypersensitive to reward, so that the presence or the prospect of receiving, reward dominates their behavior.     

Rat strain differences in nicotine self-administration using an unlimited access paradigm

An effective animal model for elucidating the neurobiological basis of human smoking should simulate important aspects of this behavior. Therefore, a 23 h unlimited access nicotine self-administration model was used to compare inbred Lewis rats, which have a propensity to self-administer drugs of abuse, to inbred Fisher 344 rats and to the outbred Holtzman strain. Using this unlimited access model, 88.8% of Lewis vs. 57.1% of Holtzman rats achieved maintenance self-administration at a fixed ratio 1 (FR 1) at 0.03 mg/kg IV nicotine (P<0.05). In contrast, Fisher rats did not acquire self-administration under these conditions. Of the Lewis and Holtzman rats that achieved maintenance self-administration on an FR 1 schedule, a greater percentage of Lewis rats acquired nicotine self-administration at FR 2 (P<0.05) and progressed to FR 4 (P<0.05). Using naïve cohorts in a progressive dose reduction study, 83.3% of Lewis rats achieved maintenance at 0.0075 mg/kg nicotine as compared to 31.8% of Holtzman rats (P<0.05). Furthermore, only Lewis rats showed differences in active vs. inactive bar presses during maintenance at sequential dose reductions (P<0.001). Thus, in this unlimited access model, inbred Lewis rats will more reliably acquire nicotine self-administration than outbred Holtzman rats. Moreover, Lewis rats showed a significantly higher likelihood of continuing to self-administer nicotine in face of both increasing work requirements and decreasing drug reinforcement. Therefore, it is likely that Lewis rats would be genetically susceptible to nicotine addiction.     

非理想均匀磁场和线性梯度磁场中扩散衰减对温度和时间依赖性的比较

目的:比较非理想均匀磁场和线性梯度磁场中扩散运动引起的信号衰减对温度、时间的依赖性。方法:用经典物理学的扩散理论探讨扩散运动引起的信号衰减与温度、时间的关系。结果:非理想均匀磁场和线性梯度磁场中扩散运动引起的信号衰减因子分别为A(t)随机=e-r2tB2Δt2和A(t)梯度=e-r22GΔ2t3td2。结论:在非理想均匀磁场及线性梯度磁场中扩散衰减对时间t的依赖性的变化趋势是一致的,只是在线性梯度磁场中这种依赖性显得更强。而扩散衰减对温度的依赖性在两种磁场中正好彼此相反。     

苯二氮革类药物在住院精神病患者中使用现状

目的：调查苯二氮革类药物（BZD）在住院精神病患者中的应用情况。方法：对本院2004年所有住院精神病患者182例应用BZD的临床资料进行回顾性分析，对出院时仍在服用BZD的患者66例随访，用CCMD3诊断标准诊断其BZD依赖情况。结果：调查发现182例住院精神病患者中143例应用过BZD，占78．87％，其中单用1种的123例（86．01％），2种合用的20例（13．99％），药物应用依次为地西泮、艾司唑仑、阿普唑仑、氯硝西泮、劳拉西泮、硝西泮等，随访的66例患者中，因故仅随访52例，BZD依赖18例（34．62％）。结论：BZD在住院精神病患者中应用范围广泛、时间较长、剂量偏大，存在明显滥用情况，易导致患者出院后BZD依赖。     

Effects of alcohol consumption on indices of iron stores and of iron stores on alcohol intake markers

BACKGROUND: Alcohol increases body iron stores. Alcohol and iron may increase oxidative stress and the risk of alcohol-related liver disease. The relationship between low or "safe" levels of alcohol use and indices of body iron stores, and the factors that affect the alcohol-iron relationship, have not been fully characterized. Other aspects of the biological response to alcohol use have been reported to depend on iron status. METHODS: We have measured serum iron, transferrin, and ferritin as indices of iron stores in 3375 adult twin subjects recruited through the Australian Twin Registry. Information on alcohol use and dependence and smoking was obtained from questionnaires and interviews. RESULTS: Serum iron and ferritin increased progressively across classes of alcohol intake. The effects of beer consumption were greater than those of wine or spirits. Ferritin concentration was significantly higher in subjects who had ever been alcohol dependent. There was no evidence of interactions between HFE genotype or body mass index and alcohol. Alcohol intake-adjusted carbohydrate-deficient transferrin was increased in women in the lowest quartile of ferritin results, whereas adjusted gamma-glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase values were increased in subjects with high ferritin. CONCLUSIONS: Alcohol intake at low level increases ferritin and, by inference, body iron stores. This may be either beneficial or harmful, depending on circumstances. The response of biological markers of alcohol intake can be affected by body iron stores; this has implications for test sensitivity and specificity and for variation in biological responses to alcohol use.     

Ethanol dependence has limited effects on GABA or glutamate transporters in rat brain

BACKGROUND: Neuroadaptations of GABAergic and glutamatergic systems appear to play an important role in both the acute as well as chronic effects of ethanol. Chronic ethanol intake leads to the development of ethanol tolerance and dependence that is associated with a decrease in GABAergic and an increase in glutamatergic function. The present report assessed the involvement of GABA and glutamate transporters in the chronic ethanol-induced adaptations of these two neuronal systems. METHODS: Male and female rats were made ethanol dependent by 2-week administration of ethanol in a liquid diet. Levels of GABA (GAT-1, GAT-3) and glutamate (GLT-1, EAAC-1) transporters were assayed by immunoblotting. Transporter function was assessed by [3H]GABA and [3H]glutamate uptake assays. RESULTS: Ethanol dependence did not alter levels of GABA or glutamate transporters in cerebral cortex compared with pair-fed control values. There were increases in some, but not all, transporter levels in hippocampus and hypothalamus with the development of ethanol dependence. A decreased rate of uptake was observed for GABA in cerebral cortex. There was no change in maximal GABA uptake or in glutamate uptake (Vmax). CONCLUSIONS: These results suggest that alterations in GABA and glutamate transporters have only a limited role in neuroadaptations to chronic ethanol intake in rats. However, the observed alterations were region-specific, supporting the complex responses to chronic ethanol exposure and suggesting that neuroadaptations of GABAergic and glutamatergic systems vary across the brain.