Diabetic Infarction Research Articles

Increased incidence of “persistently positive” technetium pyrophosphate myocardial scintigrams following myocardial infarction in diabetics

Increased incidence of “persistently positive” technetium pyrophosphate myocardial scintigrams following myocardial infarction in diabetics

糖尿病と動脈硬化

Arteriosclerotic disorders are frequently observed in diabetics and obviously play an important role in the prognosis in these patients. It is unclear whether the diabetes affects the arteries in an independent, characteristic risk factor fashion or whether the susceptibility to other risk factors is involved. The frequency of cardiovascular death in diabetics is over 70% in the U.S.A. while the percentage is 40-50 in Japan. In statistics found in the autopsy reports published by the Japan Society of Pathology in 1975, deaths due to myocardial and cerebral infarction in diabetics were, respectively, two to three times higher than in non-diabetics. This ratio was compatible with that of most other countries. The Framingham study indicated that a high incidence of cardiovascular disease in diabetics could not be explained simply by the frequency of each risk factor. Thus, diabetes is considered to play the role of an independent risk factor in arteriosclerotic-related diseases.Specific mechanisms of regulation of blood pressure and hypertension in diabetics have been well discussed by Christlieb and other workers. Hyaline degeneration of renal arterioles which often parallels the low renin states often occurs in the initial stage of diabetic nephropathy. It has been suggested that hypertension in diabetics is caused by an aggravation of the changes in renal arterioles and the glomeruli, there by inducing a resistance to renal blood flow and disorders in the compensatory regulation of the renin-angiotensin-aldosterone system. From our observations, both basal and stimulated renin activities were lower in diabetics, especially those who had an accompanying retinopathy and proteinuria, as compared to non-diabetics. The ratio of aldosterone to renin, however, was rather high in diabetics, as determined after upright position and intravenous injection of furosemide. In the regulation of blood pressure in diabetics, disorders in aldosterone and renin secretion were thus considered to play an important role and the clinical application for anti-aldosterone agents should probably be reevaluated.Attention has been focused on platelet function as related to mechanisms of thrombus formation in arteriosclerotic lesions. Recently, we determined thromboxane B2 levels in plasma from diabetics by a radioimmunoassay method of our own design. These levels in diabetics were found to be significantly higher than in the non-diabetics controls, and such findings imply that the turnover of platelets and the release of thromboxane A2 from platelets are accelerated in diabetics. On the other hand, Silberbauer reported that the content of prostacyclin in the vessel wall was decreased in diabetics. Thus, prostaglandin metabolism in platelets and vessels plays an important role in diabetic angiopathy.Enhancement of adhesion and aggregation of platelets have long been evidenced in diabetics. In our patients also there was an enhancement of platelet aggregation, particularly in those with retinopathy and this enhacement decreased in the insulin-treated patients to a much greater extent than in those treated with only diet or oral agents. Enhancement of platelet aggregation was also found in the low insulin response group during 50g OGTT and was improved after intravenous administration of insulin, 0.05 units per kilogram of body weight, while there were no significant alterations in blood sugar and plasma insulin levels. The addition of 100 and 1, 000μU of insulin to platelet rich plasma suppressed significantly adrenaline-induced platelet aggregation. Further experiments revealed the existence of specific binding sites of insulin, insulin receptors, in the platelets themselves. Platelet aggregability was followed up for two years in diabetics treated with diet alone and in those given insulin.

Statistical Study on 471 Episodes of Myocardial Infarction in Diabetics in Japan. Relationship Between Early Death From Myocardial Infarction and Therapeutic Methods of Diabetes.

Statistical Study on 471 Episodes of Myocardial Infarction in Diabetics in Japan. Relationship Between Early Death From Myocardial Infarction and Therapeutic Methods of Diabetes.

Myocardial Infarction in Diabetics

The hospital mortality of acute myocardial infarction amongst 285 known diabetics treated in the last decade was 39.7 per cent at one month and had increased to 51 per cent at 12 months. Treatment in a coronary care unit during the acute stage had little effect on the mortality amongst patients on insulin, but was beneficial for patients whose diabetes had been controlled by oral hypoglycaemic drugs. Female patients on oral hypoglycaemic drugs had the highest mortality. When considering age, duration of diabetes and presence of retinopathy, acute myocardial infarction in diabetics controlled on oral therapy appeared to have a worse outcome than in patients on insulin. Independently of whether patients were on insulin or on oral hypoglycaemic drugs 12 months after the acute episode, only about half of them were still alive.

Current status of the epidemiology of brain infarction associated with occlusive arterial disease.

Although large gaps in our knowledge concerning the epidemiology of cerebrovascular disease are apparent, careful inspection of all existing data now makes it possible to see certain patterns emerging which suggest certain risk factors for stroke. While the problem of differential diagnosis of the various categories of cerebrovascular disease presents a major obstacle to obtaining an undistorted picture of the epidemiological features of stroke from death certificate mortality data, the addition of evidence from prospective studies, including those in Framingham, Massachusetts, reveals that various types of arterial occlusion with cerebral infarction are by far the most prevalent type of stroke. Any specific origin of atherosclerosis remains obscure, as possible etiological candidates including dietary alterations in salt, fat and refined carbohydrate, sedentary living, excessive calories promoting obesity, the cigarette habit and even the mineral content of water in addition to marital status have all been incriminated. However uncertain the final answer is, certain precursors for atherosclerosis, such as hypertension, diabetes, and hyperlipidemia, are important. Of these, hypertension is clearly the most important contributor to stroke incidence. Certain combinations of items carry more risk than do the same items singly. For example, the risk of a brain infarction in diabetics with hypertension is probably about six times that of normal subjects. In persons under 50 at the time of measurement risk of cerebral infarction is possibly ten times higher in those with hypertension and elevated lipids than in those without either elevated. This compounding of risk has pathogenetic, preventive and public health implications. For purposes of stroke screening alone the most efficient and practical method would be to determine casual blood pressure, although it must be stated that as yet there is uncertainty concerning the change in the risk if such blood pressure is treated.

New quantitative vectorcardiographic criteria for the detection of unsuspected myocardial infarction in diabetics

New quantitative vectorcardiographic criteria for the detection of unsuspected myocardial infarction in diabetics

Chemico-anatomic studies of arteriosclerosis and thrombosis in diabetics: II. Fatty acids of adipose tissue and plasma lipids in several groups of North American diabetics and nondiabetics

It has been well established by both clinical and autopsy studies that myocardial infarction is much more common in North American white diabetics compared with nondiabetics. In this study the possible interrelationships between myocardial infarcts, diabetes and adipose tissue fatty acids and plasma lipids were studied by comparing diabetics unselected as to the presence or absence of complications with age- and sex-matched nondiabetics. Adipose tissue fatty acids were measured because of the suggested abnormal release of fatty acids from tissue stores in the diabetic. Only palmitic acid of six adipose tissue fatty acids compared in diabetics and nondiabetics was found to be significantly different, and this only in female diabetics, compared to female nondiabetics. The biologic significance of this finding is questionable. The finding of similar linoleic acid values in North American diabetics and nondiabetics suggests that there is no deficiency of linoleic acid in the diabetic adipose tissue stores contributing to the greater incidence of myocardial infarction in this group. Among plasma lipids, no difference was found in comparing plasma cholesterol levels. However, triglycerides (in both male and female diabetics) and lipid phosphorus (in female diabetics) were found to be elevated when compared to levels in nondiabetics. The elevated serum triglycerides in the diabetic group in this study is in keeping with the serum triglyceride levels found in other groups of diabetics who have strikingly different frequencies of myocardial infarction. North American white, North American Negro, and East African diabetics, with a high, intermediate, and low frequency of myocardial infarction respectively showed high, intermediate, and low levels of serum triglyceride. Although the evidence is far from complete, there is at least some reason to believe that plasma lipids are involved in the clotting mechanism. It is possible that the elevated plasma lipids found in this group of diabetics may explain the greater susceptibility to coronary artery thrombosis and myocardial infarction in diabetes.

The immediate prognosis of cardiac infarction in diabetics.

The immediate prognosis of cardiac infarction in diabetics.