Salt-Induced hypertension in rats alters the response of isolated aortic rings to cromakalim

The effect of cromakalim, an opener of ATP-sensitive potassium (K atp) channel, on precontracted aortic rings from control and salt-loaded rats was studied in spague-Dawley rats. Salt-loading experiments involved the induction of hypertension by 6-week feeding of 80 g sodium chloride(NaCl)per kilogram(kg) diet while the control diet had 3 g NaCl per kg diet. Blood pressure and heart rate were determined by cannulation of a femoral artery under urethane/a-chloralose anaesthesia. Isolated aortic rings were mounted in tissue baths for isometric tension measurement. The sodium-potassium adenosine triphosphstase (Na-KATPase) pump activity was measured by potassium(K)-induced relaxation (with or without ouabain) following precontraction with 10-7 M noradrenaline.The KATP channel was studied by measuring the relaxation response to cromakalim,precontracted with either 10-7M noradrenalineor 60mM potassiumchloride(KCl). The Na- k ATPase pump appeared to be inhibited during salt loading. ATPase inactivation was found to be ouabain sensitive but did not seem to affect subsequent K - induced contraction. Cromakalim produced relaxation of noradrenaline precontracted rings frem the control rats; rings from salt-loaded rats showed significantly less relaxtion than control(p<0.05) under similar conditions. During K-induced precontraction, cromakalim produced a weak biphasic response in the control rings-an initial relaxation and then a reversal. Cromakalim produced further contraction of K-induced precontraction in salt-loaded group. The results suggest that ATP-sensitive potassium channels and Na-K ATPase pumps on the vascular smooth muscle membrane may be deactivated in the development of hypertension during salt loading.(AU)

Intrapericardial heart and great vessel injuries

Eighteen patients with intrapericardial penetrating injuries of the heart or great vessels are reviewed, and the results compared with other published material. The majority presented with injuries of the left anterior chest wall and with clinical evidence of cardiac tamponade. Most of the injuries resulted from stab wounds, and there were two deaths which occurred in the immediate peri-operative period. The importance and clinical recognition of cardiac tamponade is stressed. Immediate thoracotomy and repair of the cardiac wound is advocated, and pericardiocentesis is recommended only as a temporary measure to allow transportation of the patient to definitive care. (AU)

Closure of aorto-pulmonary window in infancy using cardiopulmonary bypass

A case is described of a Jamaican Negro female infant with resistant cardiac failure due to an aorta-pulmonary window which was successfully closed using a cardio-pulmonary bypass operation (AU)

Variation in human aortic fatty streaks among geographic locations

Histological features of aortic fatty streaks were examined in male subjects aged 10-39 from Guatemala, Jamaica Negro, Durban Bantu, New Orleans Negro, New Orleans white, Lima and Santiago. These groups were selected from the 19 available in the IAP (International Atheroschlerosis Project) because they represented the greatest contrasts between the extent of fatty streaks in the young and raised lesions in the elders. Among these seven groups the extent of raised lesions in the older subjects was significantly but weakly correlated with the type of fatty streaks in the young as measured by lesion thickness, content of demonstrable lipid, numbers of foam and spindle cells. The severity of leukocytic infiltration and prevalence of foci of necrosis in fatty streaks however, correalted strongly with raised lesions (rank r=0.90). We interpret this to imply that the presence of leukocytes and of foci of necrosis in the fatty streak marks its propensity to progress into raised lesions. If this formulation is correct, then the presence of both features in the histology of fatty streaks could be used as a marker in future studies of factors bearing upon the emergence of raised lesions out of fatty streaks (AU)

Fatty streaks in the coronary arteries and aorta

We have analyzed the extent of fatty streaks in the coronary arteries and aortae of young persons 10 to 39 years old from 19 geographic and ethnic groups. Fatty streaks in the aorta increase rapidly in succeeding age groups during the second decade of life, and in some groups during the third decade. There after they tend to diminish in extent or remain at approximately the same level. Fibrous plaques and other advanced lesions approach similar degrees of extent 20 years or more later. The extent of aortic fatty streaks in youth does not predict the extent of aortic raised lesions later in life on agroup basis. Fatty streaks in the second and the third decades of life, and show no tendency to regress at any age. The mean extent of coronary artery fatty streaks in young persons appears related to the mean extent of raised lesions in the same population at middle age in non-Negro groups. These data are consistent with the hypothesis that advanced atherosclerotic lesions develop by progression and transformation of fatty streaks. However, the degree to which the transformation takes place appears to vary among arteries and among racial groups. (AU)

Dilatation and unfolding of the aorta in a Jamaican population

In an analysis of 2085 70 mm. chest X-rays of subjects aged 35-64 from a rural population in Jamaica, 79 of the 1090 women (8.4 percent) showed some degree of aortic dilatation. The clinical examination of these people and age and sex balanced control groups drawn by random methods from the same population revealed three main findings. (1) Arterial pressure levels were consistently higher in the affected, than in the controls. (2) The conditions was associated with aortic regurgitation in 20 percent of men and 7 percent of women. (3) Both aortic dilatation and arterial pressure in these subjects were apparently unrelated to their present serological status. Positive serological reactions were found in about 25 percent of affected and controls. The possible role of syphillis and/or yaws in association with hypertension in producing aortic dilatation is discussed. A relationship between aortic dilatation, often gross, and hypertension has been demonstrated and this combination appears to have a high prevalence in West Indian negroes. Whatever the role of treponemal infection it is apparently not the most important single factor in the production of either the aortic dilatation, the associate hypertension, or the resulting aortic regurgitation. The significance of uncomplicated aortic dilatation, in terms of morbidity and mortality, remains to be determined by follow-up studies of these groups (Summary)

Some factors influencing the development of atherosclerosis: A survey in Jamaica, West Indies

Using a quantitative method of assay the degree of atherosclerosis of the aorta, coronary arteries and cerebral arteries has been determined in a large, predominantly Negro, autopsy series in Jamaica, West Indies. There is a progressive worsening of the disease with age but there are considerable individual variations at all ages. The aorta, coronary and cerebral arteries are affected in that order in time and severity. Atherosclerosis is generally more severe in men and hypertension accentuates the disease, especially in women after the menopause. Hypertension is more important than atherosclerosis in causing cerebrovascular disease in Jamaica. Diabetes alone does not seem to influence adversely the development of atherosclerosis except in combination with hypertension. Evidence for the effect of malignant disease was inconclusive. Severe degrees of atherosclerosis are encountered in the Jamaican Negro but the supposed complications are relatively uncommon. This supports the view that factors other than initial disease, principally those connected with thrombosis, are concerned in the pathogenesis of ischaemic vascular disease. (AU)

Geographic differences in the severity of aortic and coronary atherosclerosis

Comparison of aortic and coronary atherosclerosis in the United States, Jamaica, Japan and India demonstrates that after the first two decades of life, there is a greater severity of intimal alteration in the United States than in the other population groups. The 3 foreign populations exhibited much less coronary atherosclerosis and a lower incidence of myocardial infarction. Their diets, too, were of lower caloric content and contained less than half the fat found in the United States diet. In Japan and Jamaica, atherosclerosis proved to be disproportionately more severe in the aorta than in the coronary arteries. Accordingly, appraisals of atherosclerosis limited to the aorta do no provide adequate indexes of geographical variations. A much lower proportion of complicated atheromatous lesions (ulcerated or calcified plaques) accounted for most of the differences observed. While there was a general parallelism between the severity of coronary atherosclerosis and the frequency of myocardial infarction, there were instances of cardiac infarction associated with relatively minor degrees of coronary intimal alteration. These situations indicate that virtually all grossly recognizable intimal lesions may be complicated by thrombosis (Summary)

Spontaneous rupture of a papillary muscle of the heart

An unusual case of ruptured papillary muscle of the heart is desired. The study of serial sections revealed a small aneurysm in the ruptured papillary muscle. The cause of the aneurysm was not certain but it was probably syphilitic. (Summary))

Heart disease in Jamaica

The cardiac cases admitted to an adult male and female ward of the University College Hospital of the West Indies during 1956 and '57 have been analysed and the autopsy incidence of heart lesions in the first 1258 cases seen in the Pathology Department of the University College of the West Indies has been reviewed. (AU)

Atherosclerosis of the aorta in Jamaica (abstract only)

As part of a geographical survey of atherosclerosis a method has been used to assess qualitatively and quantitatively the degree of sortic atherosclerosis at routine autopsy. To date 368 cases from all age groups have been studies in Jamaica. A preliminary analysis of the results has been made and compared with similar published series. Contrary to what has been claimed by other authors the Jamaican figures would appear to indicate that there is not necessarily a direct correlation between the degree of aortic atherosclerosis and the liability to the development of the serious sequelae of atherosclerosis such as myocardial infarction. (AU)