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 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of the present study was to evaluate possible hemodynamic effects of somatostatin in insulin-dependent diabetic subjects. For this purpose, 7 insulin-requiring juvenile-onset diabetics were submitted to a short-term infusion of cyclic somatostatin (250 micrograms/h, over 2 h) or saline in randomized order. Somatostatin infusion resulted in a progressive and significant decrease in heart rate, stroke volume, cardiac index and velocity circumferential fiber; on the other hand, left ventricular ejection time was augmented by somatostatin. None of these effects was seen in the saline control study. We conclude that somatostatin exerts a negative inotropic effect in insulin-dependent diabetes.
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PMID:Hemodynamic effects of somatostatin in insulin-dependent diabetic subjects. 4 64

Both naturally occurring disease processes and experimental models of human disease in the Mongolian gerbil were reviewed. The gerbil was highly susceptible to cerebral infarction following unilateral ligation of one common carotid artery and was useful in studies of the pathogenesis of stroke. Spontaneous epileptiform seizures mimicked those of human idiopathic epilepsy, and both seizure-sensitive and resistant strains have been bred. Perhaps because of its more efficient nephron, the gerbil accumulated four to six times as much renal lead as the rat, and the gerbil has been proposed as an experimental model of lead nephropathy. On standard diets, about 10% of the animals became obese, and some showed decreased glucose tolerance, elevated serum immunoreactive insulin and diabetic changes in the pancreas and other organs. Some breeders exhibited hyperactivity of the adrenal cortex associated with hyperglycemia, hyperlipidemia and degenerative vascular disease. Although dietary supplements of cholesterol were toxic and did not induce atherosclerosis, the gerbil was useful in other studies of cholesterol absorption and metabolism. Spontaneous, insidious periodontal disease became evident after about 6 months on standard diets, and dental caries were induced by cariogenic diets or by pathodontic streptococci. Spontaneous neoplasia occurred in 8.4--24% of gerbils, usually after 2 years of life. Adrenal cortical, ovarian and cutaneous tumors were the most consistently reported neoplasms.
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PMID:The pathology of the Mongolian Gerbil (Meriones unguiculatus): a review. 9 95

Arteriosclerotic heart disease is a major cause of death in insulin-requiring juvenile diabetic patients treated for end-stage renal disease. Eleven consecutive diabetic patients without clinical evidence of coronary artery disease underwent complete cardiac evaluations, including coronary arteriography, as part of transplant recipient work-ups. Seven were women and four were men; their mean age was 32 (21 to 50 years). Angiographically, every patient had multifocal atherosclerotic coronary disease. Four of seven patients tested had positive-stress electrocardiograms. In this group of patients followed for a mean of 19.8 months, eight died. Of these deaths, six were due to coronary heart disease and another due to a stroke. In two patients who became clinically symptomatic, serial angiograms revealed progressive disease of the coronary circulation; in one case, despite normal renal allograft function and serum lipid levels. The mode of end-stage renal disease treatment, serum lipids or blood pressure control could not be linked to mortality. It is concluded that arteriosclerotic heart disease is common in diabetic patients with end-stage renal disease even when angina is absent. The natural history in this high risk population is an important consideration in the selection of patients for end-stage renal disease treatment.
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PMID:Natural history of asymptomatic coronary arteriographic lesions in diabetic patients with end-stage renal disease. 36 Aug 37

Present methods of management of juvenile-onset diabetes mellitus do not prevent serious and debilitating complications affecting multiple organ systems. In an effort to reverse advanced forms of these complications, segmental transplantation of the pancreas has been performed on 10 patients, seven of whom simultaneously or subsequently received renal transplants. Long periods of normoglycemia (two to four and one-half years) were achieved in two patients who also maintained transplant kidney function. The course of these two patients is described to illustrate the possible value and limitations of the procedure. These patients had normal blood glucose levels, exhibited repeated normal intravenous glucose tolerance curves, and had repeated normal endogenous insulin levels. Their courses were characterized by (1) absence of problems related to pancreatic exocrine secretions into the bladder; (2) stable eye changes despite some episodes of hemorrhage from preexisting retinopathy; (3) vascular complications, including stroke and gangrene of extremities necessitating amputation despite successful femoropopliteal bypass grafting; (4) peripheral neuropathy; and (5) repeated infections. Both patients succumbed to vascular complications. Thus, pancreatic transplantation can maintain blood glucose and insulin at normal levels for extended periods of time. However, it does not reverse such complications as advanced retinopathy or atherosclerosis. Since the procedure may have value in preventing progression of these complications, it should be evaluated in patients with less advanced complications of diabetes.
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PMID:Long-term effects of pancreatic transplant function in patients with advanced juvenile-onset diabetes. 40 Jan 24

Cardiac performance and some parameters of glycolytic and oxidative metabolism were analyzed in isolated perfused guinea pig hearts performing pressure-volume work. Perfusion medium was an oxygenated Krebs-Henseleit bicarbonate buffer (pH 7.4) which contained glucose and physiological concentrations of pyruvate and insulin. The pressure-flow relationship in the coronary vascular bed indicated autoregulation of coronary flow. Left ventricular function was influenced by aortic pressure (Pa) and venous filling pressure (Pv) in accordance with the Frank-Starling principle, i.e. stroke work increased as a function of Pa or Pv to a certain maximum and then decreased. Myocardial oxygen consumption (MVO2), on the other hand, was linearly correlated with Pa and Pv, respectively, over the entire pressure range. Efficiency of the left ventricle, therefore, increased to an optimum (16%) and decreased at higher pressures. Myocardial contents of glycogen, ATP and creatine phosphate were not markedly influenced by a change in Pa or Pv. L-Noradrenaline (0.08 micrometer, NA) stimulated stroke work and MVO2 at a all Pv tested; efficiencies reached physiologic values (21%) at high volume loads. The increased MVO2 was associated with an acceleration of pyruvate decarboxylation and lactate release up to 10- and 15-fold, respectively, at elevated but physiological NA concentrations (0.2 micrometer). Our results demonstrate that the isolated perfused working guinea pig heart compares favourably with the non-failing Starling heart-lung preparation and hearts in situ, as far as coronary function, left ventricular performance and oxidative metabolism are concerned.
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PMID:Functional and metabolic features of an isolated perfused guinea pig heart performing pressure-volume work. 57 65

To evaluate the influence of glucose infusate administered with insulin and potassium on left ventricular function during 4 h of ischemia, as well as mechanism of action, four groups of intact anesthetized dogs were studied. Acute regional ischemia was induced with a balloon tip catheter in the left anterior descending artery and infusates were begun after 20 min of ischemia. A threefold increase of plasma glucose concentration was associated with improved left ventricular function during ischemia, compared to animals receiving isovolumic saline. There was a significant decline of left ventricular end-diastolic pressure associated with elevation of stroke volume and ejection fraction to control levels, as determined by indicator dilution. In a separate subgroup studied by cineangiography, shortening of the ischemic anterior wall, after an initial decline, was increased in response to glucose but there was no evidence of extension of injury. Ischemic tissue exhibited a smaller gain of water as well as Na+ per gram dry weight as compared to ischemic controls. On precordial electrocardiogram mapping there was a significant decrease in the sigmaST (sum of ST elevation) as well as NST (number of ST segment elevations), but the reduction of R wave amplitude was not different from controls. To further evaluate long-term effects, eight controls and six treated animals underwent myocardial ischemia and were sacrificed after 4 mo. Calculated area and weight of scar, as well as degree of wall thinning, were similar in both groups. The glucose-treated animals had a significant decrease of plasma FFA in contrast to controls which manifested a significant rise. To examine the postulate that the decrease in FFA was important to therapeutic action, a third group was infused with Intralipid (Cutter Laboratories, Inc., Berkeley, Calif.) and heparin, simultaneously with the glucose infusate, to effect an elevation of plasma FFA during ischemia. Changes in myocardial function and electrolyte composition, as well as precordial electrocardiogram mapping, were similar to that of animals receiving glucose alone. Because serum osmolality was increased approximately 40 mosmol during the glucose infusion, the potential role of hyperosmolality was assessed by infusion of 20% mannitol during acute ischemia in a fourth group. After a transient small increase, there was a moderate decline in function by 4 h, suggesting that the response to glucose is not dependent upon extracellular osmolality. Thus, it is concluded that during the initial hours after the onset of myocardial ischemia the glucose infusate improves ventricular performance without evidence of arrhythmia induction or intensification of ischemic injury. Evolution of irreversible necrosis appears to be delayed rather than prevented under the circumstances of this study.
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PMID:Sustained effect of glucose-insulin-potassium on myocardial performance during regional ischemia. Role of free fatty acid and osmolality. 65 87

To evaluate the importance of time, temperature, and cardioplegia on the ability of the canine myocardium to maintain functional and ultrastructural integrity following induced arrest, we studied 220 dogs by varying myocardial temperature (34 degrees, 24 degrees, and 11 degrees C.), arrest time (0 to 120 minutes), and cardioplegic agents. Change in left ventricular function (LVF) was defined as the arithmetic difference in the center of mass between prearrest and postarrest LVF curves and was expressed as percent recovery of left ventricular stroke work. Left ventricular biopsies were obtained for semiquantitative electron microscopic analysis. After 90 minutes of cross-clamping, only hearts protected with combined hypothermia (H) and potassium-induced cardioplegia (K) significantly recovered prearrest function (24 degrees C.--80 percent, 11 degrees C.--99 percent). Hypothermia (H) alone for 90 minutes was less protective (24 degrees C.--49 percent, 11 degrees C.--59 percent). H preserved 84 percent of function after 60 minutes and 91 percent after 45 minutes. Normothermic arrest resulted in only 39 percent return of function at 45 minutes but could be extended with potassium-induced cardioplegia(K) to 78 percent at 60 minutes and 54 percent at 90 minutes. The addition of procaine plus HK improved protection over HK alone (95 percent versus 80 percent) but by itself was not effective. Neither hydrocortisone nor pretreatment with glucose-insulin-potassium, branched chain amino acids, or propranolol increased the protective effect of HK plus procaine. Inadequately protected groups (normothermia or H without K) showed more myocytic and capillary endothelial damage than the HK groups. No technique of myocardial protection studied completely preserved LVF, but the combination of HK plus procaine resulted in maximal recovery of LVF following cross-clamping for up to 120 minutes.
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PMID:Effect of cross-clamp time, temperature, and cardioplegic agents on myocardial function after induced arrest. 70 64

It was established in experiments on adult (8--12 month) and old (26--32 month) rats that in ageing the sensitivity of the cardiovascular system to certain hormones--adrenaline, vasopressin, insulin, thyroxine, estradiol dipropionate--grows while its reactivity to them diminishes. The administration of these hormones causes significant changes in hemodynamics and myocardial contractility. Adrenaline and thyroxine lead to an increase in the blood minute and stroke volume, arterial pressure, cardiac index and left ventricular work index, maximum rate of intraventricular pressure growth, maximum rate of myocardial fiber shortening, and in the contrastility index. Vasopressin and insulin cause a decrease in the indices of general hemodynamics. The increased sensitivity of the heart to hormones at old age and diminution of its reactivity lead to prolonged, protracted reactions of the cardiovascular system in elderly and old individuals.
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PMID:[Hormonal regulation of the heart in aging]. 73 78

Coronary heart disease is the most frequent cause of death in Western, industrialized countries. Coronary risk factors are prevalent in such countries and sometimes combine to constitute the so-called syndrome X--hypertension, central obesity, serum lipid and clotting disturbances, and insulin resistance. beta-Blockers, unlike calcium antagonists, have proved highly effective in secondary prevention of myocardial infarction. If present at the time of the myocardial infarction, beta-blockers (unlike calcium antagonists and diuretics) probably decrease mortality 1 month later. Early intervention (within 12 h) of chest pain with intravenous beta-blockers results in a 15% reduction in cardiovascular mortality at 1 week. Later intervention (3-28 days) with oral non-ISA beta-blockers results in a 30% reduction in mortality after 1 year; ISA-containing beta-blockers are probably less effective (less decrease in heart rate). Hydrophilicity/lipophilicity of beta-blockers is unimportant in terms of decreased mortality. Primary prevention of myocardial infarction, unlike stroke, in hypertensive patients has been disappointing, possibly due to treatment-induced biochemical/lipid changes or inappropriate lowering of diastolic blood pressure in high-risk subjects (J-curve effect). beta-Blockers should be first-line therapy for hypertensive patients up to the age of 65 years, particularly men (and nonsmokers) as Q-wave myocardial infarction is significantly decreased by beta-blockers and significantly increased by diuretics. However, in elderly hypertensive subjects, beta-blockers have not significantly decreased myocardial infarction (unlike stroke), whereas diuretics have. The effects of beta-blockers and diuretics on heart size (and thus coronary flow reserve) in the elderly may be important. Thus, beta-blockers should be second-line therapy for the elderly hypertensive individual but first-line if overt ischemia (e.g., angina or recent myocardial infarction) also is present. In patients with angina but normal blood pressure, beta-blockers tend to decrease and calcium antagonists increase cardiovascular events. Thus, beta-blockers are highly effective agents in the secondary prevention of myocardial infarction and are moderately effective in primary prevention of myocardial infarction in hypertensive patients (particularly men) under the age of 65 years.
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PMID:Beta-blockers: primary and secondary prevention. 128 45

Twenty-eight severely ill, hospitalized Nigerian patients, 18 males and 10 females with a median age of 41 years (group I) and 20 stable ambulatory patients, 11 males and 9 females with a median age of 42.5 years (group II), had early morning plasma cortisol measurements. Ten healthy young Nigerian males with a mean age of 22.1 years (group III) had plasma cortisol estimations during insulin tolerance test. The mean (+/- SD) cortisol values for the three groups in nmols/l were as follows: group I--389.3 (202.4), group II--267.1 (67.4), group III-624.5 (81.1). The results for the group III healthy controls represent the peak (60 mins) value during insulin induced hypoglycemic stress. A one way analysis of variance (ANOVA) demonstrated a statistically significant difference between the three mean cortisol values, P < 0.001. A pair-wise comparison using the t-test also showed significant differences between the groups, P < 0.05 in each case. An important observation was the variable pattern of cortisol stress response in different types of illnesses. Cases of stroke appeared to be associated with increased cortisol stress values (Z-score + 5.67) while patients with hypotension (B.P. < or = 90/60) and those on Rifampicin had reduced cortisol responses (Z-scores - 3.66 and 3.51 respectively). However, no firm recommendations can as yet be made regarding the usefulness of corticosteroids in life-threatening illnesses among Nigerians, other than those for which steroids are known to beneficial.
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PMID:Pattern of adrenocortical response to the stress of severe illness in Nigerians. 128 46


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