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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemolytic uremic syndrome (HUS) is defined as microangiopathic hemolytic anemia, thrombocytopenia and uremia. It is an important cause of acute renal failure (ARF) in children all over the world. The present study was carried out to assess the incidence, clinical presentation, hematological and biochemical profile of children presenting with HUS from 1987 to 1990. Out of the 100 cases who presented with ARF 22 had HUS. A majority of these children were males below 1 year of age, and had a prodromal phase of mainly gastrointestinal manifestations lasting for about a week. Anemia was a constant feature followed by bleeding diathesis, mainly melena and purpura. Neurological manifestations included altered sensorium, irritability, coma, hypertensive encephalopathy and convulsions. Renal problems mainly included oliguria, hypertension, hematuria and edema. Investigations revealed thrombocytopenia and microangiopathic hemolytic anemia in all cases. Evidence of disseminated intravascular coagulation (DIC) was observed in 3 cases as decreased fibrinogen levels, increased fibrinogen degradation products and deranged clotting studies. Blood biochemistry revealed azotemia in all cases, hyponatremia in 5 cases, hypernatremia in 3 cases and hyperkalemia in 12 cases. Stool culture showed the presence of Shigella in 8, E. coli in 6 and Klebsiella in 4 cases. Out of 22 cases of HUS, 15 were treated conservatively; of these 2 died. Both of these deaths were due to DIC 7 children were put on peritoneal dialysis; only 1 child died in this group. Factors affecting the outcome were duration of oliguria, levels of blood urea and presence of encephalopathy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A clinico-hematological profile of hemolytic-uremic syndrome. 788 99

Essential hypertension is one of the most common diseases that exacerbate the risk of cardiovascular or cerebrovascular attacks. Although the etiology of essential hypertension remains unclear, recent investigations have revealed that an enhancement of Na(+)-proton (Na(+)-H+) exchange activity is a frequently observed ion transport abnormality in hypertensive patients and animal models. To test the hypothesis that increased Na(+)-H+ exchange causes hypertension, we produced transgenic mice overexpressing Na(+)-H+ exchanger and analyzed their Na+ metabolism and blood pressure. Urinary excretion of water and Na+ was significantly decreased in transgenic mice, and systolic blood pressure was elevated after salt loading. The impaired urinary excretion of Na+ suggested that the Na(+)-H+ exchanger overexpressed in the renal tubules increased reabsorption of Na+, which caused a blood pressure elevation by Na+ retention after excessive salt intake. Our results demonstrate that overexpression of Na(+)-H+ exchanger can be a genetic factor that interacts with excessive salt intake and causes salt-sensitive blood pressure elevation.
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PMID:Salt-sensitive hypertension in transgenic mice overexpressing Na(+)-proton exchanger. 800 Dec 73

Epidemiologic studies from divergent geographic locations consistently demonstrate an inverse correlation between potassium intake and the prevalence of hypertension. Studies in experimental animals showed a varied blood pressure response to alterations in potassium intake. Spontaneously hypertensive rats and rats with renovascular hypertension manifest a hypotensive response to both potassium depletion and potassium supplementation. In contrast, potassium depletion induced by chronic mineralocorticoid administration is associated with an increase in blood pressure. Potassium supplementation in hypertensive subjects lowers blood pressure. Amelioration of diuretic-induced hypokalemia with potassium supplementation enhances the hypotensive effect of diuretics. Potassium depletion induced by dietary potassium restriction elevates blood pressure in normotensive and hypertensive subjects maintained on a normal sodium intake. Potassium depletion in humans is accompanied by sodium retention and calcium depletion. The hypertensive response to potassium depletion and the hypotensive response to potassium supplementation do not manifest if sodium intake is kept low. Sodium retention, altered response to vasoactive hormones, direct vasoconstrictive effects of hypokalemia, and calcium depletion may all contribute to blood pressure elevation during potassium depletion.
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PMID:Role of potassium in the pathogenesis of hypertension. 814 Nov 60

Association between insulin resistance and hypertension: Insulin resistance and reactive hyperinsulinemia occur not only with obesity, impaired glucose tolerance or non-insulin-dependent (type 2) diabetes mellitus, but also in many non-obese, non-diabetic patients with essential hypertension and their currently normotensive, lean young offspring and in some other conditions known to promote hypertension. Insulin resistance impairs glucose tolerance, while insulin resistance and/or hyperinsulinemia promote dyslipidemia, body fat deposition and probably atherogenesis. Therefore, the common coexistence of a genetic predisposition for hypertension with insulin resistance helps to explain the frequent, although temporally often dissociated, occurrence of hypertension as well as dyslipidemia, obesity and type 2 diabetes in a given subject. Pathogenetic mechanisms: In the pathogenesis of hypertension, inappropriate vasoconstriction (due to dysbalance of vasoactive substances and/or raised cytosolic Ca2+) and/or a structural vasculopathy is a very important ultimate causative event. In the presumed mosaic of participating pressor mechanisms, distinct Na+ retention is almost obligatory with diabetes mellitus, while essential and particularly obesity-associated hypertension probably involves a tendency for sympathetic activation. Development of insulin resistance: Insulin resistance may develop as a consequence of an intracellular excess of Ca2+ or decrease in Mg2+, an impaired insulin-mediated rise in skeletal muscle blood flow, increased sympathetic activity or being overweight. Acute hyperinsulinemia on the one hand causes arterial vasodilation and on the other hand enhances renal sodium reabsorption and sympathetic activity. Chronically, hyperinsulinemia may promote cardiovascular muscle cell proliferation and atherogenesis, and it has been proposed that insulin resistance in certain transmembranous cation exchange systems may elevate cytosolic Ca2+. Nevertheless, whether insulin resistance and/or hyperinsulinemia itself contribute to the pathogenesis of hypertension is still unclear.
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PMID:Insulin resistance, hyperinsulinemia and hypertension. 815 79

Chronic nitric oxide (NO) inhibition promotes hypertension and ischemic glomerular injury with only minor glomerulosclerosis (GS). We evaluated the effect of superimposed salt overload, which has been shown to aggravate GS in other models. Fifteen days of treatment with the NO inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) promoted marked arterial and glomerular hypertension, hyporeninemia, and slight renal interstitial expansion, but no glomerular injury. Salt overload slightly exacerbated systemic and glomerular hypertension, promoted albuminuria, interstitial expansion, and glomerular ischemia, and paradoxically reversed hyporeninemia. The angiotensin II inhibitor losartan attenuated glomerular and systemic hypertension and prevented renal injury in these rats. Thirty days of treatment with L-NAME resulted in marked hypertension, hyperreninemia, interstitial expansion, and glomerular ischemia. Concomitant salt overload exacerbated hypertension, interstitial expansion, and ischemia and promoted massive albuminuria, GS, and creatinine retention. Losartan attenuated these effects. Sodium overload aggravates the renal and systemic consequences of chronic NO inhibition by mechanisms that may include paradoxical activation of renin secretion. Interstitial expansion and glomerular ischemia, rather than GS, constitute the chief modalities of renal injury in this model.
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PMID:Sodium excess aggravates hypertension and renal parenchymal injury in rats with chronic NO inhibition. 820 52

Sodium bicarbonate is an extremely well-known agent that historically has been used for a variety of medical conditions. Despite the widespread use of oral bicarbonate, little documented toxicity has occurred, and the emergency medicine literature contains no reports of toxicity caused by the ingestion of baking soda. Risks of acute and chronic oral bicarbonate ingestion include metabolic alkalosis, hypernatremia, hypertension, gastric rupture, hyporeninemia, hypokalemia, hypochloremia, intravascular volume depletion, and urinary alkalinization. Abrupt cessation of chronic excessive bicarbonate ingestion may result in hyperkalemia, hypoaldosteronism, volume contraction, and disruption of calcium and phosphorus metabolism. The case of a patient with three hospital admissions in 4 months, all the result of excessive oral intake of bicarbonate for symptomatic relief of dyspepsia is reported. Evaluation and treatment of patients with acute bicarbonate ingestion is discussed.
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PMID:Acute toxicity from baking soda ingestion. 828 75

This study examined the control of renal hemodynamics and tubular function, as well as systemic hemodynamics, during obesity-induced hypertension in chronically instrumented conscious dogs. Mean arterial pressure, cardiac output, and heart rate were monitored 24 hours a day using computerized methods, water and electrolyte balances were measured daily, and renal hemodynamics were measured each week during the control period and 5 weeks of a high-fat diet. After 7 to 10 days of control measurements, 0.5 to 0.9 kg of cooked beef fat was added to the regular diet, and sodium intake was maintained constant at 76 mmol/d throughout the study. After 5 weeks of the high-fat diet, body weight increased from 24.0 +/- 1.0 to 35.9 +/- 4.9 kg, mean arterial pressure increased from 83 +/- 5 to 100 +/- 4 mm Hg, cardiac output increased from 2.86 +/- 0.27 to 4.45 +/- 0.55 L/min, and heart rate rose from 68 +/- 5 to 107 +/- 9 beats per minute. Associated with the hypertension was an increase in cumulative sodium balance to 507 +/- 107 mmol after 35 days and a rise in sodium iothalamate space, an index of extracellular fluid volume, to 131 +/- 4% of control. Sodium retention was due to increased tubular reabsorption, because glomerular filtration rate and effective renal plasma flow increased throughout the 5 weeks of the high-fat diet, averaging 135 +/- 4% and 149 +/- 19% of control, respectively, during the fifth week of the high-fat diet.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1993 Sep
PMID:Obesity-induced hypertension. Renal function and systemic hemodynamics. 834 21

Sodium retention has been advocated to give rise to hypertension in humans. Increases in blood glucose and insulin concentrations ensue in the stimulation of sodium reabsorption by the kidney. Although the combined occurrence of hyperglycemia and hyperinsulinemia, frequently secondary to insulin resistance with regard to carbohydrate metabolism, is a hallmark of non-insulin dependent diabetes (NIDDM), the role of these abnormalities in determining an impaired natriuresis in NIDDM is not yet fully understood. We studied sodium homeostasis in 14 control subjects and 59 NIDDM normotensive, normoalbuminuric patients who were divided into two groups with markedly impaired (Group 2 NIDDM: 30) and less severely impaired (Group 1 NIDDM: 29) insulin sensitivity during euglycemic-hyperinsulinemic (80 to 90 microU/ml plasma insulin) clamp. A hyperglycemic (9 mmol/liter plasma glucose)--nearly euinsulinemic (20 to 40 microU/ml plasma insulin) clamp was also performed in the same 14 controls and in two cohorts of 22 Group 2 and 17 Group 1 NIDDM patients. The two groups of patients had similar overnight fasting glucose levels (Group 1 NIDDM vs. Group 2 NIDDM: 176 +/- 13 vs. 185 +/- 15 mg/dl, mean +/- SE). Conversely, overnight fasting plasma insulin was significantly higher in Group 2 NIDDM than in Group 1 NIDDM patients (Group 1 NIDDM vs. Group 2 NIDDM: 12 +/- 3 vs. 18 +/- 3 microU/ml, P < 0.05). Both NIDDM Groups had higher plasma glucose and insulin than controls (75 +/- 4 mg/dl and 6 +/- 3 microU/ml). Blood pressure levels and albumin excretion rates were slightly but significantly higher in Group 2 NIDDM, but not in Group 1 NIDDM patients, than in controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of hyperglycemia and insulin resistance in determining sodium retention in non-insulin-dependent diabetes. 835 55

The renin-angiotensin-aldosterone hormonal axis is the major long-term servocontrol for regulation of both arterial blood pressure and sodium balance. It supports normotension or hypertension via angiotensin vasoconstriction and angiotensin plus aldosterone-induced renal sodium retention. Normally, in the presence of hypertension or sodium-volume excess, plasma renin activity promptly falls to zero. Accordingly, any renal secretion of renin in the face of high blood pressure is abnormal. In established essential hypertension varying degrees of abnormal plasma renin activity operate to cause or sustain the hypertension; only very low plasma renin values reflect a normal renal response. Human hypertensive disorders comprise a spectrum of abnormal plasma renin-sodium volume products. High renin, intensely vasoconstricted, hypovolemic forms (e.g., malignant, renovascular) are one extreme of the spectrum; "wet"-volume-excess low-renin forms are the other extreme (e.g., primary aldosteronism, low-renin essential hypertension). These varying, but abnormal renin-sodium products are caused by a renal lesion in which a subpopulation of ischemic nephrons hypersecretes renin and retains sodium despite systemic hypertension and sodium excess. Thus, hypertensive patients cannot suppress their renin secretion normally. The hypertension from this renal lesion is correctable by agents that reduce renin secretion or block its effect (beta blockade, CEI, renin inhibition, or angiotensin II antagonism). None of these agents lower blood pressure after binephrectomy, verifying the renal origin of renin in the cardiovascular control system. In essential hypertension, the plasma renin level appears as a continuous variable associated with greater risk of ischemic injury.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The renin system and new understanding of the complications of hypertension and their treatment. 849 72

GENETIC PREDISPOSITION: Insulin resistance and reactive hyperinsulinemia occur not only with obesity, impaired glucose tolerance or non-insulin-dependent (type 2) diabetes mellitus, but also in many non-obese, non-diabetic patients with essential hypertension and their currently normotensive, lean, young offspring, as well as in some other conditions known to promote hypertension. Insulin resistance impairs glucose tolerance, while insulin resistance and/or hyperinsulinemia promote dyslipidemia, body fat deposition and probably atherogenesis. Therefore, the common coexistence of a genetic predisposition for hypertension with insulin resistance helps to explain the frequent, although temporally often dissociated, occurrence of hypertension together with dyslipidemia, obesity and type 2 diabetes in a given patient. INSULIN RESISTANCE AND HYPERINSULINEMIA AS SLOW PRESSOR MECHANISMS: In the pathogenesis of hypertension, inappropriate vasoconstriction (due to an imbalance of vasoactive substances and/or raised cytosolic calcium) and/or structural vasculopathy is particularly important. Among the mosaic of assumed pressor mechanisms, distinct Na+ retention is almost invariably involved in diabetes mellitus, while sympathetic activation tends to occur in essential hypertension, particularly in association with obesity. Insulin resistance may develop as a consequence of an intracellular excess of Ca2+ or a decrease in Mg2+, an impaired insulin-mediated rise in skeletal muscle blood flow, increased sympathetic activity or excess body weight. Acute hyperinsulinemia causes arterial vasodilation on one hand and increases sympathetic activity and renal Na+ reabsorption on the other. Chronically, hyperinsulinemia may promote cardiovascular muscle cell proliferation and atherogenesis, while insulin resistance may be associated with certain transmembraneous cation transporters, leading to an increase in cytosolic Ca2+. Hyperinsulinemia and/or insulin resistance may also be associated with an increased blood pressure sensitivity to high salt intake. In the mosaic of many different blood pressure-raising mechanisms, insulin resistance and/or hyperinsulinemia is likely to represent an amplifying slow or very slow pressor factor.
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PMID:Insulin resistance and hyperinsulinemia in hypertension. 857 90


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