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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The effect of administration of the angiotensin converting enzyme inhibitor (ACEI), lisinopril (Carace; 10-40 mg twice daily) and the calcium channel blocker, nifedipine (Adalat Retard; 20-40 mg twice daily) on ex vivo [45Ca2+] uptake by platelets from hypertensive diabetic (type 1 and 2) patients was investigated. 2. At the end of at least 3 months treatment, blood was collected prior to the patient taking the morning dose of medication and washed platelets prepared. [45Ca2+] uptake was monitored following the addition of adrenaline, isoprenaline and dibutyryl cAMP (dbcAMP), as well as in unstimulated (zero) platelets. 3. Both nifedipine and lisinopril significantly inhibited the ex vivo uptake of [45Ca2+] by platelets when this process was stimulated by adrenaline, isoprenaline and dibutyryl cAMP. Basal uptake was also inhibited in both groups. 4. These data consolidate the hypothesis that ACE inhibitors may possess calcium channel/calcium mobilisation blocking properties. Apart from its hypertensive action, lisinopril may also reduce platelet activity via modulation of calcium dynamics, thereby reducing the incidence of vascular complications associated with diabetes mellitus.
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PMID:Lisinopril and nifedipine administration inhibits the ex vivo uptake of [45Ca2+] by platelets from hypertensive diabetic patients. 131 54

Research on antihypertensive drugs not only provides new information on presently used agents but also leads to the introduction of exciting new compounds. Several important clinical trials involving currently available drugs have been published recently. Angiotensin-converting enzyme inhibitors improved survival in patients with milder degrees of congestive heart failure, which indicates that they have become the cornerstone of treatment for this condition. Angiotensin-converting enzyme inhibitors delayed or prevented the development of diabetic proteinuria (> 200 micrograms/min) in a placebo-controlled randomized trial. Further, enalapril was more effective than metoprolol in reducing the rate of decline in renal function in patients with type I diabetes. Calcium channel blockers protected against acute renal failure in patients after renal transplantation in two separate studies. Calcium channel blockers were shown to promote natriuresis, with negative sodium balance the same as that associated with thiazide diuretics. The voltage-dependent calcium channel has been cloned, and the binding sites of the three classes of calcium channel blockers are now known. beta-Blockers and thiazide diuretics were the drug treatments in the Systolic Hypertension in the Elderly Program trial and in the Swedish Trial in Old Patients with Hypertension study (patients 65 to 85 years). In both investigations, stroke and cardiovascular events were significantly reduced by these conventional inexpensive agents. Clonidine was found to lower blood pressure primarily by its interaction with the imidazole receptor rather than the alpha 2 receptor. Elucidation of the imidazole receptor promises to shed light on physiologic mechanisms as well as lead to the introduction of new agents, such as moxonidine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:New classes of antihypertensive drugs and new findings with established agents. 136 36

We have investigated the cellular basis for the clinical and epidemiologic linkage of hypertension, left ventricular hypertrophy (LVH), obesity, and non-insulin-dependent diabetes mellitus (NIDDM) and have studied cytosolic free calcium and free magnesium levels in these syndromes. Specifically, intracellular free calcium is elevated and free magnesium is deficient in hypertension, and both are related (directly and inversely, respectively) to the ambient level of blood pressure, to LV mass index (and thus to the degree of cardiac hypertrophy), and to the hyperinsulinemia and insulin resistance of essential hypertension. Dynamically, the ability of dietary salt loading to elevate blood pressure corresponds to its ability to elevate cytosolic free calcium and reciprocally to suppress free magnesium levels. Conversely, the ability of calcium channel blockade to reverse salt-induced hypertension is related to its ability to prevent these transmembrane ionic effects. Higher steady-state free calcium or lower free magnesium, or both, are also observed in clinical states linked to hypertension, such as obesity and NIDDM. Oral glucose loading in normal subjects itself elevates free calcium and suppresses free magnesium levels, as does hyperglycemia in vitro. These data suggest an ionic hypothesis of cardiovascular and metabolic disease, in which a generalized defect in cell ion handling is present in all tissues, resulting in higher steady-state free calcium and lower free magnesium levels. In pancreatic beta cells, this would produce hyperinsulinemia; in fat and skeletal muscle, cause peripheral insulin resistance; and in renal tissue, increase proximal sodium resorption and increase urinary calcium excretion--all features of essential hypertension. In vascular smooth muscle, high cytosolic free calcium would increase smooth muscle tone and cause vasoconstriction, and in heart muscle, independent of blood pressure, would increase contractility and predispose to LVH. Therefore, what may appear clinically to be the separate syndromes of hypertension, obesity, and NIDDM may pathophysiologically be different manifestations of the same underlying cellular defect, thus explaining their frequent clinical coexistence. Therapeutically, reversal of this excess free calcium accumulation and/or free magnesium deficit with ion-specific agents, such as calcium channel blocking drugs, may thus ameliorate not only the elevated blood pressure of hypertension but also the concurrent excess morbidity and mortality of the concurrent cardiac, vascular, and metabolic aspects of the hypertensive state.
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PMID:Cellular calcium and magnesium metabolism in the pathophysiology and treatment of hypertension and related metabolic disorders. 138 62

The increasingly frequent use of contrast-enhanced imaging for diagnosis or intervention in patients with peripheral vascular disease has generated concern about the incidence and avoidance of contrast-induced nephrotoxicity (CIN). In this prospective study, we sought to identify those patients at greater risk of developing CIN and to evaluate the efficacy of vasodilator therapy with dopamine in limiting this complication. Baseline serum creatinine (Cr) concentrations were obtained on admission and daily for up to 72 hr after angiography in 222 patients undergoing 232 angiographic procedures. The preangiographic treatment was varied at 2-month intervals for 1 year. All patients received an intravenous infusion of 5% dextrose and 0.45% normal saline at a rate of 75 to 125 ml/hr. During the first interval patients received 12.5 g of 25% mannitol immediately prior to their contrast load, in addition to intravenous fluids. During the next 2-month period the patients were given renal dose dopamine intravenously (3 micrograms/kg/min) commencing the evening before angiography and continued to the next morning. During the latter half of the study the treatment regimens were modified so that the use of mannitol was restricted to patients with diabetes mellitus and dopamine to patients with serum creatinine concentrations of > or = 2 mg/dl. Postangiographic elevation in Cr occurred in 2, 10.4, and 62% of studies in patients with baseline creatinine levels of < or = 1.2 mg/dl, 1.3 to 1.9 mg/dl, and > or = 2.0 mg/dl, respectively. None of the patients receiving dopamine experienced an elevation in creatinine. There was no statistical correlation between age, diabetes, or medication with calcium channel blockers and CIN.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Contrast-induced nephrotoxicity: the effects of vasodilator therapy. 140 11

The purpose of our review is to delineate the pathogenic steps linking arterial hypertension in diabetes to diabetic nephropathy. The results of recent studies suggest that arterial hypertension in diabetes might lay a decisive pathogenetic role in the evolution of diabetic nephropathy: the existence of a higher ratio of erythrocytic Na/Li counter-transport in nephropathic diabetics as well as higher pressure values in the parents of diabetics who develop nephropathy indicates that hypertension may be casually related to renal complications. Diabetes-associated hypertension involves the modification of two important pressure- regulation factors: 1. an alteration in extracellular volume and increased renal absorption of sodium which leads to an expanded pool; 2. increased cardiovascular reactivity to norepinephrine and angiotensin II, an effect which might be related to increased intracellular calcium. Hyperfiltration seems to be present at the onset of diabetes, and arterial hypertension increases the transglomerular pressure gradient which is thought to play an important role in the pathogenesis of kidney damage. Antihypertensive drugs such as ACE-inhibitors and calcium channel blockers tend to protect the regulation of renal function. This could be explained by the fact that ACE-inhibitors suppress the trophic effects of angiotensin II on the nephron, while calcium channel blockers might interfere with intracellular processes involved in cell hypertrophy that require the interaction of calcium ions. In the management of diabetes prevention of diabetic nephropathy requires early and careful correction of diabetes-associated hypertension. We discuss the major groups of antihypertensive drugs, their metabolic side-effects and intrarenal induced hemodynamic changes.
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PMID:[Diabetic nephropathy and arterial hypertension: the physiopathological aspects and antihypertensive treatment]. 145 55

Recent data suggests that reduced nerve blood flow is implicated in the aetiology of experimental diabetic neuropathy, which may be prevented by manipulations that reduce receptor-mediated vasoconstrictor activity. This investigation examines the effects of nifedipine, a voltage-sensitive calcium channel antagonist which has a direct vasodilatory effect on vessels, on nerve conduction, hypoxic resistance and capillary density in streptozotocin-induced diabetic rats. Treated and non-treated non-diabetic and diabetic groups were employed. Diabetes duration was 2 months. Treatment was preventive, groups received a nifedipine dietary supplement (40 mg.kg-1.day-1) for 2 months from the start of the study. Conduction was measured in sciatic motor branches supplying tibialis anterior and gastrocnemius muscles, and sensory saphenous nerve. Diabetes resulted in a 23-28% reduction in motor conduction velocity (p < 0.001), and a 15% deficit for sensory saphenous nerve (p < 0.001). In the nifedipine-treated diabetic group, motor and sensory conduction deficits were minimal compared with non-treated diabetes (p < 0.001). Nifedipine treatment had no significant effect on conduction velocity in non-diabetic rats. In vitro measurement of sciatic nerve hypoxic resistance revealed a 60% increase in the time taken for compound action potential amplitude to reach half its initial value with diabetes (p < 0.001). This was not significantly affected by nifedipine treatment. Experimental diabetes or nifedipine treatment did not significantly alter sciatic nerve endoneurial capillary density. We conclude that nifedipine, a vasodilator which acts directly on vascular smooth muscle, prevents nerve conduction deficits in experimental diabetes.
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PMID:The effect of the calcium antagonist nifedipine on peripheral nerve function in streptozotocin-diabetic rats. 147 62

The review summarizes recent data about the use of calcium channel blockers for the treatment of cardiovascular complications in patients with diabetes mellitus. It is shown that disturbances of Ca ion homeostasis play an important role in the pathogenesis of such diabetic complications as cardiomyopathy, microangiopathy, hypertension and the use of modern calcium channel antagonists for their treatment seems to be quite justified. However, despite definite positive effects of such treatment, these drugs should be used with care, especially if combined with derivatives of sulphonylurea as activators of the beta-cell function. Calcium channel blockers may intervene in the mechanism of the activity of beta-cells in which activation of the calcium channels is an obligatory link for triggering insulin secretion. Nevertheless, according to most of the authors, in such cases Ca antagonists can be recommended in moderate doses under continuous control of the hormonal status of the patient.
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PMID:[Current aspects of the mechanism of action of calcium antagonists in patients with diabetes mellitus]. 149 54

Experimental animal studies have demonstrated a renal protective effect of ACE inhibition therapy in diabetes mellitus and the remnant kidney model of chronic renal failure. The mechanism of this effect is secondary, at least in part, to the drugs' effects on glomerular hemodynamics. In addition, there is further evidence to suggest that ACE inhibitors may influence other pathogenic mechanisms of progressive renal insufficiency. Preliminary data in clinical studies suggest that ACE inhibition therapy decreases proteinuria and may ameliorate the decline of the glomerular filtration rate in diabetic nephropathy and progressive renal insufficiency of other etiologies. However, before this conclusion can be definite, a large, prospective, randomized clinical trial is required to compare ACE inhibitors to conventional antihypertensive agents. Since calcium channel blockers are metabolically neutral in that they do not increase serum cholesterol or glucose levels and generally do not cause orthostatic hypotension, they may be ideal agents for such a comparison study.
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PMID:Progressive renal insufficiency: the role of angiotensin converting enzyme inhibitors. 155 7

Cardiovascular disease represents the major cause of morbidity and mortality in noninsulin-dependent diabetic patients. While it was once thought that atherosclerotic vascular disease was responsible for all of these adverse effects, recent studies support the notion that one of the major adverse complications of diabetes is the development of a diabetic cardiomyopathy characterized by defects in both diastolic and systolic function. Contributing to the development of the cardiomyopathy is a shift in myosin isozyme content in favor of the least active V3 form. Also defective in the noninsulin-dependent diabetic heart is regulation of calcium homeostasis. While transport of calcium by the sarcolemmal and sarcoplasmic reticular calcium pumps are minimally affected by noninsulin-dependent diabetes, significant impairment occurs in sarcolemmal Na(+)-Ca2+ exchanger activity. This defect limits the ability of of the diabetic heart to extrude calcium, contributing to an elevation in [Ca2+]i. Also promoting the accumulation of calcium by the diabetic cell is a decrease in Na+, K+ ATPase activity, which is known to increase [Ca2+]i secondary to a rise in [Na+]i. In addition, calcium influx via the calcium channel is stimulated. Although the molecular mechanisms underlying these defects are presently unknown, the possibility that they may be related to aberrations in glucose or lipid metabolism are considered. The evidence suggests that classical theories of glucose toxicity, such as excessive polyol production or glycosylation, appear to be insignificant factors in heart. Also insignificant are defects in lipid metabolism leading to accumulation of toxic lipid amphiphiles or triacylglycerol. Rather, the major defects involve membrane changes, such as phosphatidylethanolamine N-methylation and protein phosphorylation, which can be attributed to the state of insulin resistance.
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PMID:Cardiomyopathy associated with noninsulin-dependent diabetes. 166 89

Recent studies in animal models suggest that glomerular capillary hyperperfusion and hypertension, rather than ischemia, cause renal injury. Interventions that control glomerular capillary hypertension may protect against progressive injury, even in the presence of continued systemic hypertension. In the absence of systemic hypertension, diabetes mellitus is a prominent clinical example of glomerular hypertension. Animal studies have shown that glomerular hemodynamic abnormalities, especially elevations in glomerular pressure, play an important role in the pathogenesis of diabetic glomerulopathy. A number of clinical observations suggest that angiotensin converting enzyme (ACE) inhibitors may delay the progression of diabetic nephropathy by their effects on renal hemodynamics. In experimental animals, comparisons between calcium channel blockers and ACE inhibitors have shown the latter to be more effective in protecting the kidneys. Preliminary clinical studies indicate that ACE inhibitors may have advantages in preserving renal function in hypertensive and diabetic patients with renal failure.
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PMID:Renal effects of converting enzyme inhibitors in hypertension and diabetes. 169 12


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