乌头碱致心律失常毒性作用的剂量分析

用静脉灌注方法，分别对３种浓度的乌头碱致大鼠心律失常作用进行了观察，经Ｆ和Ｆ＇分析，各浓度组间室早和室颤潜伏时间差异具有非常显著性意义（Ｐ＜０．０１），而各浓度组间致心律失常阈剂量无显著差异（Ｐ＞０．０５）．用０．０１～１００×１０－５ｍｏｌ·Ｌ－１乌头碱灌流离体蟾蜍心脏，结果表明随浓度加大，心脏收缩的抑制率增强，心律失常发生率增高，室早和室颤潜伏时间缩短，呈现明显的浓度依赖性。     

Application of finite-element analysis with optimisation to assess thein vivo non-linear myocardial material properties using echocardiographic imaging

An application of finite-element analysis with an optimisation technique to assess the myocardial material properties in diastasisin vivo is described. Using the data collected from an animal model, the three-dimensional geometry of the left ventricular chamber, at several times in diastole, was reconstructed. From the measurement of the ventricular chamber pressure during image acquisition, finite-element analysis was performed to predict the expansion during diastasis. Initially, by restricting the motion of the epicardial nodes and computing the reaction forces, an ‘equivalent pericardial pressure’ was determined and applied in subsequent analysis. The duration of diastasis was divided into three or four intervals and the analysis was performed at each interval to assess the material properties of the myocardium. Using such a step-wise linear approach, the non-linear material properties of the myocardium during passive expansion was determined. Our results demonstrated that the computed ‘equivalent pericardial pressure’ increased with and was smaller than the corresponding left ventricularchamber pressure. The passive myocardium exhibited a linear tangent modulus against chamber pressure relationship which is equivalent to an exponential stress/strain relationship, similar to those suggested byin vitro studies.     

Cortical activity and sleep in the rat lateral hypothalamic syndrome

Continuous EEG recordings were performed in lateral hypothalamic (LH) damaged rats from day 1 post-lesion when totally aphagic and adipsic until complete recovery of their feeding and drinking. During the early post-operative stage (days 1–3 post-lesion), LH rats showed a complete disorganization of their basal EEG which was characterized by two superimposed activities, a constant rapid low voltage activity modulated by high voltage low frequency waves. Except in the case of intense illumination, several arousing stimuli did not affect this activity. By day 4 post-lesion, the two overlapping activities were replaced by less abnormal waves on top of which the first normal sleep spindles appeared. Sleep increased gradually and normal amounts of both slow-wave and paradoxical sleep were observed during ‘stage 4’ of recovery when rats again ate food and drank water. During this stage, and contrary to normal rats, meal size was correlated only with sleep events occurring within the intermeal interval following the next meal, when most of the ingested nutrients reached the systematic compartment. The effect on sleep of intragastric or intravenous caloric repletion was, at least in part, in agreement with the view of indirect effect of LH lesions on sleep through metabolic impairment. Whatever the mechanism underlying sleep deficits, these are one of the major symptoms of the lateral hypothalamic syndrome.     

Voluntary drinking of ethanol by the rat: Biogenic amines and possible underlying mechanism

The present study evaluates the possible relationship between certain biogenic amine metabolites-produced changes in voluntary drinking of ethyl alcohol (ET) solution by the rat and their in vivo effects on the enzymes primarily involved in the hepatic metabolism of ET, i.e., liver alcohol-(L-ADH) and aldehyde dehydrogenase (L-ALDH). In experiments on voluntary intake of ET solution by the rat, compounds selected were injected, 0.5 mM/kg, IP. Administration of vanillylmandelic acid (VMA) and 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA) markedly reduced ET drinking. Similar significant effects were seen after administration of the neutral metabolites of the biogenic amines tested, after injection of metanephrine or 3-methoxy-4-hydroxyphenylpyuric acid. Threodihydroxyphenylserine but not L-dopa reduced ET intake by the rat. Treatment with peripheral decarboxylase inhibitors, i.e., carbidopa, 50 mg/kg, IP, significantly reduced ET drinking as contrasted with nonsignificant decline in ET consumption following benserazide, 500 mg/kg, IP. In the biochemical study, short-term administration of the compounds selected produced varied effects on L-ADH and L-ALDH. It is suggested that alteration of hepatic ADH by the compounds tested might account for the observed reduced ET drinking, thereby indicating the contribution of peripheral sources rather than central factors in mediating the behavioral effects studied.     

CYCLIC ANALOGUE OF BRADYKININ POSSESSING SELECTIVE AND PROLONGED BIOLOGICAL ACTIVITY

Cyclo-[(Nε¹-Lys¹, Gly⁶)-bradykinin] and its deprotected non-cyclic precursor, PheGlyProPheArg-LysProProGly, were synthesized using the conventional methods of peptide chemistry. Similar to bradykinin, the cyclopeptide elicits a depressor reaction in rats, as revealed by the experiments in vivo. Its duration of action, however, is greater by several orders of magnitude. At the same time, it appears to exhibit no myotropic activity when applied in vitro to extravasal smooth muscle preparations (uterus and ileum of the rat). The non-cyclic precursor lacks the depressor activity, but produces a slight myotropic effect (α= 0.6 ± 0.09; pD₂= 5.9 ± 0.17).     

Dating and relationship issues

Conclusions The subject of dating and relationships for women with disabilities is one of those areas for which we have many more questions than answers, more suggested tendencies than demonstrated patterns of variables. If research pursuits reflect social values, it makes sense that a society that has long ignored or disdained the gender role of women with disabilities has invested little effort in understanding their potential for love, partnership and motherhood. Faced with an intolerable information void, women with disabilities have been increasingly forthright in reporting our relationship experiences our goals, our joy, and our solitariness. The generosity of those who tell their stories has helped all of us women with disabilities to become more visible as women. There remain, however, too many unknowns. Women with disabilities want facts to guide our efforts—efforts cautiously and thriftily expended by necessity. More than ever, we feel entitled to better research studies that address our dreams. Some of our most urgently asked questions concern relationships. What makes a woman with a disability attractive to a partner? How do you navigate the obstacles from attraction to commitment? How have some women with disabilities managed to be more successful than others in relationships? What are the relationship experiences of lesbians with disabilities? What factors determine the viability of “mixed” partnerships involving individuals with and without disabilities, and how do such persons surmount the obstacles of prejudice and frustration? What factors lead to and enhance intimacy between partners with disabilities? These are the questions of women with a growing sense of entitlement to being heard and to being adequately understood. Women with disabilities are becoming as determined to find answers as we have always been determined to find love.     

BINDING OF LOOP DIURETICS TO THEIR RENAL RECEPTORS: USE AS A SCREENING MODEL FOR POTENTIAL DIURETIC ACTIVITY

Loop diuretics of the benzoic acid and aryloxyacetic acid families inhibit Na+K+Cl- cotransport. The ranking order of potencies measured in the thick ascending limb of Henle's loop and the ranking order of affinities for [3H]piretanide receptors on renal plasma membranes are the same. Potencies and affinities correlate well (correlation coefficient r = 0.959 for the medulla and r = 0.951 for the cortex). Therefore, measurement of [3H]piretanide binding is proposed to facilitate screening for loop diuretic action.