Adaptive changes in cerebral blood flow and oxygen consumption during ethanol intoxication in the rat

Cerebral blood flow (CBF) and oxygen consumption (CMRO₂) were measured during acute and long-term ethanol intoxication in the rat. The purpose was to investigate whether the adaptive changes (development of tolerance) occurring in the CNS during ethanol intoxication were associated with changes in CBF and/or CMRO₂. Consistent with other studies we found that acute severe ethanol intoxication (median blood alcohol concentration (BAC=5.4 mg/ml)) caused a significant decrease in CBF and CMRO₂. After 3–4 days of severe intoxication (BAC of 6.6 mg/ml) these physiological variables were less affected indicating that functional tolerance had developed: CMRO₂ and CBF during acute ethanol intoxication were 9.3 ml/100 g/min and 60 ml/100 g/min respectively; after the long term intoxication period these variables reached 11.2 ml/100 g/min and 78 ml/100 g/min respectively, i.e. values not significantly lower than those of the control group. After induction of hypercapnia (PaCO₂ about 80 mmHg) CBF increased by 360% in the control group; in the acutely intoxicated group CBF increased by only 127% and in the long term intoxicated group by 203 % indicating that the cerebrovascular CO₂-reactivity had also adapted to the ethanol intoxication. It is concluded that adaptive changes of the CNS to chronic ethanol intoxication comprise alterations in CMRO₂, CBF and cerebrovascular reactivity.     

Ampullary electroreceptors in catfish (Teleostei): temperature dependence of stimulus transduction

The response properties of ampullary electroreceptors have been studied in the catfish Ictalurus nebulosus at skin temperatures between 5 and 35 °C. A unimodal relationship between spontaneous activity and temperature was obtained. Mean (±SEM) peak discharge rate was 57.3 ±1.8 impulses s^–1 at 25 ° C; the receptors were active at 5 °C (15.0 impulses s^–1) and at 35 °C (31.5 impulses s^–1). There were no dynamic responses to temperature changes in either the warming or cooling direction. The shape of the frequency characteristic depended on temperature: the peak of the gain curve shifted to low frequencies at low temperatures. There was a concomitant change of the phase characteristic: the intersection at zero degree phase angle shifted to higher frequencies with an increase of temperature, thus increasing the lead at lower frequencies and decreasing the lag at higher frequencies. Latency after combined excitatory and inhibitory impulse stimulation was temperature dependent, ranging from 16.4 ms (5 °C) to 5.6 ms (35 °C). Application of the specific calcium channel blocker menthol (0.2 mM) suppressed spontaneous activity, the effect becoming more prominent at higher temperatures. Sensitivity to sinusoidal electrical stimulation was also impaired, but to a lesser degree and mainly at lower temperatures. We conclude that the filter properties of the receptor organ can be modelled by a band-pass filter in series with a latency, both of which are temperature dependent. These filter properties might be partially based on the activation kinetics of the tranduction channels.     

The dependence of the latency relaxation on temperature in single muscle fibres of the frog

The time course of the latency relaxation was studied at various temperatures in the range 0–26°C. Over the entire range the time of onset of the drop in tension, t₁, was independent of sarcomere length. At temperatures above 12–15°C the falling phase had a point of inflexion, while at lower temperatures there was an interval during which the tension fell at a constante rate. The time when the rate of drop in tension had passed its maximum value t_1,2, the time to the maximurn drop in tension t₂, and the time when the tension crossed the resting level t₃, all showed linear dependence on sarcomere length in the range from 2.1 to 2.7–3.4 μm. In this range the durations of the intervals t_1.2-t₁, t₂-t₁, and t₃-t₁ were nearly proportional to the distance from the Z-line to the end of the zone of overlap between the thick and the thin filaments. This could be explained as the activation being a longitudinal process starting from the Z-line. The slopes (dt/dS) of the linear portions of the time variables t_1,2, t₂, and t₃ in a time-sarcomere length (S) diagram all had the same dependence on temperature giving a Q₁₀ of 1.75. Under the assumption that the activation process followed a diffusion of calcium from the Z-line region to the zone of overlap a diffusion coefficient was estimated. At room temperature it had a magnitude of about 1/20 of that for calcium chloride in water. It had a dependence on temperature corresponding to an Arrhenius activation energy of about 37 kJ/mol which is about twice the activation energy for a simple diffusion of calcium in water. The results can be interpreted in terms of the time course of the latency relaxation mainly reflecting a longitudinal diffusion of calcium ions in the sarcoplasm.     

Opioid dependence prevents the action of pertussis toxin in the guinea-pig myenteric plexus

Summary The longitudinal muscle-myenteric plexus preparation of the guinea-pig ileum has been employed for the study of the effect of pertussis toxin (IAP) on opioid dependence. Guinea-pigs were treated with IAP (120 g/kg, i.p.) either prior to chronic administration of an opioid or after opioid dependence had been established. The isolated preparations were tested in vitro for dependence; that is, the naloxone-precipitated withdrawal contracture. Naloxone almost failed to evoke a sign of dependence in preparations treated with IAP prior to chronic exposure to an opioid. In contrast, IAP failed to affect the withdrawal contracture when applied to an animal after dependence has been established. It is concluded that theN _i-unit, the substrate for IAP, plays a critical function in the development of dependence. The continuous activation of the opioid receptor associated with the development of dependence may induce changes inN _i which in turn prevent the interaction of IAP with its substrate.     

Dexamethasone suppression and multiple hormonal responses (TSH,prolactin and growth hormone) to TRH in some psychiatric disorders

Summary Baseline and TRH-induced changes of thyroid stimulating hormone (TSH), prolactin (PRL), and growth hormone (GH) were measured in 15 healthy control subjects and 63 psychiatric inpatients with DSM-III diagnoses of major depression (n = 19), schizophrenic disorder (n = 20), alcohol dependence (n = 10), and adjustment disorder (n = 14); baseline and postdexamethasone cortisol (CS) were also determined 3–6 days after the TRH-challenge. All patients and controls were women of similar mean age, weight, height, and they were free from interfering illness or drugs.Baseline TSH and PRL were lower in depression, TRH-induced TSH and PRL responses were lower in the whole patient group, but most markedly in depression and alcohol dependence. Postdexamethasone CS was significantly higher in depression, schizophrenia and alcohol dependence. Basal GH did not differentiate the subgroups; TRH-induced pathological GH responses were sometimes found in the patient groups. The differences were most marked quantitatively in major depression: a multivariate analysis of variance showed that TSH, postdexamethasone CS and PRL were the most important variables in separating patients from controls. A discriminant function derived from these variables classified all controls and 18 of 19 depressed patients correctly; however, 25 of the 44 other patients were also classified with depression.It was confirmed that psychiatric patients show significantly more endocrine disturbances than controls, and this was seen not only in major depression but also in at least three other conditions. Further work is needed to identify other neuroendocrine patterns more specific to depressive disorder.     

Autocrine and paracrine growth regulation of human breast cancer

Summary We consider the hypothesis that estrogen control of hormone dependent breast cancer is mediated by autocrine and paracrine growth factors secreted by the breast cancer cells themselves. Though we show direct, unmediated effects of estrogen on specific cell functions, we also provide evidence that human breast cancer cells secrete a collection of growth factors (IGF-I, TGF, TGF, a PDGF-like competency factor, and at least one new epithelial colony stimulating factor). Some of these are estrogen-regulated in hormone dependent cells, and are constitutively increased in cells which acquire independence either spontaneously or byras transfection. Collectively, the secreted growth factors are capable of promoting tumor formation by MCF-7 cells in nude mice, though not to the same extent as estrogens. There would seem to be potential for clinical intervention in the autocrine and paracrine control of breast cancer cells, including some cells which are no longer dependent on estrogens.     

842例工人、农民和战士最大呼气流量-容积曲线的测定

作者用“点值法”对成都市内和郊区842例从事轻、中、重劳动的健康工人、农民和战士作了MEFV曲线和常规肺功能测定,发现工人和农民在低肺容积时流量增加,在高、中肺容积时流量下降,并以农民最明显,重劳动工人次之,轻、中劳动工人较不明显,战士则相反。揭示不同的体力活动方式及生活条件可导致不同肺容积时的流量改变,以适应其代谢增强时的耗氧需求。     

Spatial clusters of daily tobacco consumption before and after a smoke-free policy implementation

This study assessed the spatial dependence of daily tobacco consumption and how it is spatially impacted by individual and neighborhood socioeconomic determinants, and tobacco consumption facilities before and after a smoke-free implementation.Individual data was obtained from the Bus Santé, a cross-sectional survey in Geneva. Spatial clusters of high and low tobacco consumption were assessed using Getis-Ord Gi*.Daily tobacco consumption was not randomly clustered in Geneva and may be impacted by tobacco consumption facilities independently of socioeconomic factors and a smoking ban. Spatial analysis should be considered to highlight the impact of smoke-free policies and guide public health interventions.     

肺癌高危人群癌症防治核心知识认知情况调查

目的 探讨肺癌高危人群对癌症防治核心知识认知情况并对其影响因素进行分析。方法 以2017年3月至2019年12月在上海市某医院胸外科完成肺癌高危人群筛查并判断为肺癌高危人群的居民为研究对象,开展癌症防治核心知识知晓情况调查,采用描述流行病学分析方法对癌症防治核心知识掌握情况进行分析,并采用单、多因素分析方法对知识掌握影响因素进行分析。结果 共纳入肺癌高危人群416例,年龄40~72岁,男性269例,女性147例,分别占64.66%、35.34%。癌症防治核心知识知晓326例,知晓率为78.4%。知晓率最高的为“体检或癌症筛查有利于早期发现癌症”、“癌症无传染性;癌症早期可无明显症状;癌症检查价格并非越高效果越好”、“戒烟有利于预防肺癌”,知晓率分别为92.79%、92.31%、90.38%。知晓率最低的为“适龄生育、母乳喂养、多进行身体活动、保持合适体重、少饮酒和定期体检有利于预防乳腺癌”、“肺癌早期筛查的有效方法”、“导致癌症发病的高风险因素”,知晓率分别为50.24%、37.98%、34.86%。二分类Logistic回归分析结果显示,年龄60~72岁（OR=0.418）、文化程度为大专及以上（OR=2.309）、职业类型为医疗卫生行业（OR=4.121）是肺癌高危人群癌症防治核心知识知晓的影响因素。结论 肺癌高危人群防癌认知的总体知晓情况较好,但还应针对年龄较大、文化程度较低及非医疗卫生行业人群进一步加强癌症防治宣传,不断提高广大居民群众的防癌知识认知水平。     

膈肌起搏器在慢性阻塞性肺疾病呼吸机依赖患者脱机中的应用临床疗效观察

目的:探讨慢性阻塞性肺疾病(COPD)呼吸机依赖患者膈肌起搏器的应用及疗效。方法:把2018年6月~2019年6月本院呼吸内科收治的COPD使用呼吸机并发生依赖的清醒患者60例作为研究对象,男27例,女33例;患者年龄60~75岁,平均(66.3±1.2)岁,随机分为观察组(运用常规治疗及护理并增加使用膈肌起搏器)和对照组(运用常规治疗及护理),每组30例,对两组脱机成功率和脱机时间进行比较。结果:观察组患者脱机情况明显优于对照组,观察组与对照组2周脱机成功率分别为83.3%和46.7%,脱机时间分别为(7.56±1.45),(9.42±1.28)d,差异均有统计学意义(P<0.05)。结论:COPD呼吸机依赖患者准备脱机前,给予膈肌起搏器治疗,可明显提高脱机成功率及缩短呼吸机使用时间。