Acute effects of nifedipine, diltiazem and their combination in patients with chronic stable angina: a double-blind, randomized, cross-over, placebo-controlled study

We evaluated the acute therapeutic effects of the oral administrationof n (10mg) and diltiazem (120 mg) alone and in combinationin 16 patients with effort angina. The 16 patients (13 men andthree women; mean age 59±7 years) performed a symptom-limitedbicycle exercise stress test 3 h after placebo or active substanceadministration. Maximal work load, exercise duration and timeto 1 mm ST segment depression were significantly increased andST depression at peak exercise was significantly decreased bythe combination of drugs. N and diltiazem alone similarly improvedexercise duration as markedly as their combination. One patientstopped the test after all three treatments for angina associatedwith ST depression > 2mm. The combination of drugs yieldedthe best symptomatic effect: only four patients complained ofangina in comparison to eight and seven patients after diltiazemand n respectively. Nifedipine and diltiazem are effective and safe antianginaldrugs. Some patients respond better to one drug than to theother. Patients who remain symptomatic in spite of maximal dosesof a single drug may derive some benefit from combination therapy.     

Psychological benefits of sports for disabled people: a review

This article reviews literature on the psychological benefits of sports for the disabled. Beginning with traditional models and resource development models of rehabilitation, an integrative model of sports for the disabled is suggested, emphasizing the concept of efficacy-based empowerment through sport. Empirical research is reviewed according to the conceptual categories of this model: (a) performance accomplishments and functional efficiency, (b) perceived self-efficacy, (c) self-concept and self-esteem, (d) personality disorders, mood states and locus of control and (e) activity level and social acceptance. This review suggests that most psychological constructs expressed within the empowerment model are positively affected by physical activity in disabled people, when applied properly. Several recommendations are outlined for beneficial application of the model in practice as well as for future research topics.     

急性缺氧条件下轻运动负荷脑电的变化及分布特征

本文实验研究了不同高度急性缺氧条件下运动状态脑电的变化,观察了低压舱内轻体力负荷对人体脑电的影响。结果表明,急性缺氧下轻体力负荷脑电的变化特点是:在以快波节律为主,α波普遍被阻抑的背景下,脑电图随缺氧高度的增加慢波(δ、θ)增加,α波出现并增加,而快波相对减少。经计算处理,δ、θ、α频段功量及分配指数随高度和时间的增加而增加。β频段功量相对稳定,但其分配指数呈降低趋势。这些变化在6000m缺氧高度具有统计学意义。     

Behavioral frequency and psychological commitment: Necessary concepts in the study of excessive exercising

Efforts to understand the associations among exercising, personality factors, and disordered eating have been the focus of much debate. However, research has been plagued by inconsistent findings, and there is evidence that classification and measurement differences are fundamental to these problems. To date, there are no studies which have defined exercise as a multifaceted construct. The purposes of this study were to establish the factor structure of a questionnaire developed to assess the core features believed to characterize excessive exercisers and to assess relationships between exercise (operationally defined as a function of behaviors and attitudes) and a number of putative risk factors. Results indicated that exercise was strongly related to weight preoccupation among women and men and that, among men, obsessive-compulsiveness was also positively related—findings which support claims that exercising and dieting tend to coexist, and they are associated with an obsessive-compulsive personality profile.     

The effect of coronary artery bypass surgery on ventricular arrhythmias

The effect of coronary artery bypass surgery (CAB) on ventriculararrhythmias (VA) was studied in a prospective investigationinvolving 32 patients (mean age 54 years) who underwent CABbecause of severe stable angina pectoris. Prior to CAB as wellas 12 months later each patient was subjected to the followinginvestigational programme: resting ECG, exercise ECG, 24-h ECG,selective coronary arteriography, ventriculography and cardiaccatheterization. Exercise ECG showed VA in only three patients.The prevalence of VA during 24-h ECG was 56 and 66% on the twooccasions (NS), while complicated VA (multiform, repetitive,R on T) was seen in 18 and 28%, respectively (NS). The persistence(number of 6-h periods showing VA) was 33 and 47% with regardto any VA (P<0.05), while complicated VA occurred in 13 and15% of the 6-h periods (NS). Except for an increase in dp/dt_max/Pat the postoperative measurement (P<0.05), no significantchange in the performance of the left ventricle was seen afterCAB though the graft patency was 77%. It is concluded that inpatients with ‘medically intractable’ stable anginapectoris, CAB does not effect the occurrence of VA to any greatextent — probably because left ventricular function isunchanged one year after as compared with that prior to CAB.     

Evolution of antithrombin III during the postoperative period

With a view to throwing some light on the age characteristics of platelets released into the blood in response to short-term physical exercise, we conducted exercise experiments on 23 healthy subjects previously injected with different platelet populations labelled with ¹¹¹In and ⁵¹Cr. Based on comparative platelet kinetic studies of pre- and post-exercise platelets and on exercise experiments carried out while labelled-platelet populations of different age composition were circulating, we cannot support the concept that the platelets released into the blood in response to exercise are enriched with young platelets. In addition, we found that simultaneously-injected large and small platelets were released to the same extent in response to exercise, but that the sequestration patterns of large and small platelets seem to be different.     

Effect of diazoxide on left ventricular performance in hypertension

Summary The effect of diazoxide on left ventricular performance during rest and isometric exercise (handgrip) was examined in 16 unselected hypertensive patients, 6 of whom had been pretreated with the beta-adrenergic blocking agent pindolol. Diazoxide regularly and promptly produced a fall in left ventricular systolic and end diastolic pressures, and an increase in heart rate and left ventricular dp/dt_max. Haemodynamic changes were maximal 2 minutes after injection of the drug and decreased little over the next 8 minutes. After beta-adrenergic blockade, diazoxide caused a more pronounced reduction in left ventricular systolic pressure and a less marked fall in end-diastolic pressure, whilst the diazoxide-induced rise in heart rate was partially and the increase of dp/dt_max was completely inhibited. The increase in systolic pressure during isometric exercise was not influenced by diazoxide, but the positive inotropic reaction was augmented. The findings appear to show that cardiac stimulation by diazoxide is due to a reflex mechanism transmitted by baroreceptors, and that improvement of cardiac performance is mainly due to a reduction of left ventricular after-load.     

The effect of physical training on insulin secretion of rat pancreatic islets

Rats were either physically trained by a 12-wk swimming program or were freely eating or weight matched, sedentary controls. Islets of Langerhans were isolated and incubated at various glucose concentrations. Within the range of physiological glucose concentrations the rate of insulin release from islets of trained rats was lower than that from islets of sedentary controls. The DNA content of the islets was similar in the different groups. The demonstrated decreased glucose sensitivity of the insulin secretory mechanism within the β-cells of trained rats may partly explain the finding of lower plasma insulin concentrations during intravenous glucose tolerance test in these rats compared with sedentary rats. Epididymal fat pads of trained rats were smaller than those of weight matched controls which in turn were smaller than those of freely eating controls, these differences being due to differences in fat cell size. The lower glucose sensitivity of the β-cells in trained rats was probably not a consequence of the low body weight and small fat depots in these rats.     

Effects of cedilanid-D and alprenolol in angina pectoris

Summary The haemodynamic effects of cedilanid-D and the -blocker, alprenolol, have been studied in 10 patients with angina pectoris. The patients received alprenolol orally and cedilanid-D or saline adminstered intravenously in a double-blind, cross-over trial. The combination caused shortening both of left ventricular ejection time and of the pre-ejection period in the same order of magnitude as found after cedilanid-D without -blockade. The patient's average work capacity, expressed as total work or terminal work load, was not changed by cedilanid-D compared to a placebo. No relationship was found between the initial size of the heart and the effect of cedilanid-D on capacity for physical work. It appears, therefore, that there is no indication for routine use of digitalis combined with -blockers in patients with angina pectoris, who do not have cardiac failure.     

Melatonin, pituitary function and stress in humans

(1) The nocturnal rise in plasma melatonin concentration continued through two cycles with continuous light occlusion by blindfolds in normal subjects. A daytime nap did not disturb the rhythm. (2) The plasma melatonin rhythm was present in patients with pituitary-adrenal and pituitary-gonadal failure, but appeared diminished or absent in patients bearing lesions at different points in the pineal afferent pathway. (3) In other patients and subjects who showed normal response of cortisol, growth hormone or prolactin after stimuli including hypoglycemia, pneumoencephalography, exercise or administration of -dopa during the daytime, there was no stimulation of plasma melatonin concentration. (4) Melatonin was not correlated with prolactin in blood or cerebrospinal fluid of patients with a wide range of plasma prolactin levels. (5) The adult human melatonin rhythm is relatively independent from pituitary, gonadal, and adrenal function, but may rely on a neural pathway similar to that controlling the rhythm in lower animals. The human melatonin rhythm may represent the output of a stable oscillator with a signal relatively free from acute perturbation by sleep, darkness, or stress sufficient to cause changes in other hormones.