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

The effect of a 6-week treatment with the calcium channel blocker nitrendipine or the angiotensin converting enzyme inhibitor enalapril on blood pressure, albuminuria, renal hemodynamics, and morphology of the nonclipped kidney was studied in rats with two-kidney, one clip renovascular hypertension. Six weeks after clipping of one renal artery, hypertensive rats (178 +/- 4 mm Hg) were randomly assigned to three groups: untreated hypertensive controls (n = 8), enalapril-treated (n = 8), or nitrendipine-treated (n = 10). Sham-operated rats served as normotensive controls (128 +/- 3 mm Hg, n = 8). After 6 weeks of treatment, renal hemodynamics (glomerular filtration rate and renal plasma flow) were measured in the anesthetized rats. Renal tissue was obtained for determination of glomerular size and sclerosis. Enalapril but not nitrendipine reduced blood pressure significantly. After 6 weeks of therapy, glomerular filtration rate was not different among the studied groups. Renal plasma flow increased, but albumin excretion and glomerulosclerosis did not change after enalapril treatment. In contrast, in the nitrendipine-treated group albuminuria increased from 12.8 +/- 2 progressively to 163 +/- 55 compared with 19.2 +/- 9 mg/24 hr in the hypertensive controls. Furthermore, glomerulosclerosis index was significantly increased in the nitrendipine-treated group compared with the hypertensive controls (0.38 +/- 0.1 versus 0.13 +/- 0.04). In addition, glomerular size was higher in the nitrendipine-treated group (14.9 +/- 0.17 10(-3) mm2) but lower in the enalapril-treated group (11.5 +/- 0.15 10(-3) mm2) compared with the hypertensive controls (12.1 +/- 0.17 10(-3) mm2).(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1992 Aug
PMID:Adverse effect of the calcium channel blocker nitrendipine on nephrosclerosis in rats with renovascular hypertension. 163 66

Hypertension is a major factor that contributes to the development of the vascular complications of diabetes mellitus, which primarily include atherosclerosis, nephropathy, and retinopathy. The mechanism of the pathophysiological effects of hypertension lies at the cellular level in the blood vessel wall, which intimately involves the function and interaction of the endothelial and vascular smooth muscle cells. Both hypertension and diabetes mellitus alter endothelial cell structure and function. In large and medium size vessels and in the kidney, endothelial dysfunction leads to enhanced growth and vasoconstriction of vascular smooth muscle cells and mesangial cells, respectively. These changes in the cells of smooth muscle lineage play a key role in the development of both atherosclerosis and glomerulosclerosis. In diabetic retinopathy, damage and altered growth of retinal capillary endothelial cells is the major pathophysiological insult leading to proliferative lesions of the retina. Thus, the endothelium emerges as a key target organ of damage in diabetes mellitus; this damage is enhanced in the presence of hypertension. An overall approach to the understanding and treatment of diabetes mellitus and its complications will be to elucidate the mechanisms of vascular disease and endothelial cell dysfunction that occur in the setting of hypertension and diabetes.
Hypertension 1992 Aug
PMID:Hypertension, the endothelial cell, and the vascular complications of diabetes mellitus. 163 68

The clinical and pathological data were compared between 88 Chinese and 88 Australian patients with IgA nephropathy, whose age, sex and course of disease identified by renal biopsy were matched. Statistical differences showed: More Chinese patients had edema and loin pain, while more Australian patients had hypertension, glomerular sclerosis and arterial and/or arteriolar abnormalities; impairment of renal function correlated with crescent body formation and loin pain with severe hematuria were only found in Chinese patients, While correlations between severe hematuria and histological changes, hypertension and glomerular sclerosis, impaired renal function and glomerular sclerosis were only seen in Australian patients. Differences between the two groups in symptoms, histological changes and clinico-pathological correlations suggest that IgA nephropathy is a heterogeneous disease, it may result from more than one factor.
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PMID:[IgA nephropathy in Chinese and Australian patients: a comparison between clinical and pathological features]. 164 29

Diabetic patients who develop proteinuria show a marked increase in cardiovascular morbidity and mortality. The precise pathogenesis of human diabetic kidney disease and the factors responsible for the susceptibility to it remain, in part, obscure. However, there is now evidence that renal disease clusters in families and that genetic factors may be of central importance in determining susceptibility. Predisposition to arterial hypertension has been suggested as playing a contributory role in the development of kidney disease. Hypertrophic processes may be implicated in the susceptibility to arterial wall damage and glomerular injury in diabetes. Interestingly, fibroblasts of patients with diabetic nephropathy show a higher Na+/H+ antiport activity and a greater 3H-thymidine incorporation into DNA than fibroblasts of diabetic patients without nephropathy. The first clinical signs of renal involvement are the appearance of microalbuminuria and a small elevation in arterial pressure. Mesangial expansion accompanies these changes. Microalbuminuria is associated with abnormalities of lipoprotein profiles and higher Na+/Li+ countertransport rates. The environmental changes brought about by diabetes could lead in susceptible individuals to increased systemic and intraglomerular pressures on the one hand and to mesangial expansion on the other. These two processes would cause proteinuria and glomerulosclerosis. Lipid abnormalities may further aggravate the renal histological damage and, in combination with hypertension, contribute to the accelerated atherosclerosis typical of patients with diabetic kidney disease. A vicious circle would thus be triggered, involving reduction in renal function, further hypertension, proteinuria, glomerular obsolence and hyperlipidaemia, and eventually end-stage renal failure or premature cardiovascular death.
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PMID:Risk factors for renal and cardiovascular disease in diabetic patients. 165 64

We designed experiments to reveal the antihypertensive properties of cicletanine, a novel antihypertensive drug, in Dahl salt-sensitive (Dahl-S) rats. Cicletanine (39 mg/kg body weight per day for 6 weeks) ameliorated the development of hypertension in Dahl-S rats fed a high-salt (4% NaCl) diet. This blood pressure reduction was associated with a decrease in heart weight and vascular wall thickness. Moreover, urinary prostacyclin (PGl2) excretion was increased with cicletanine treatment, being inversely related to systolic blood pressure. Proteinuria and urinary excretion of n-acetyl-beta-D-glucosaminidase were decreased and glomerular filtration rate was increased with this treatment. Morphological investigation revealed an improvement in glomerulosclerosis, renal tubular damage and intrarenal arterial injury in the salt-induced hypertensive rats. In contrast, trichloromethiazide, which decreased blood pressure to the same extent as cicletanine, lowered urinary PGl2 excretion and generally did not ameliorate the deteriorated renal functions and morphological abnormalities. Thus, these data indicate that cicletanine ameliorates the development of hypertension in Dahl-S rats and protects the cardiovascular and renal systems against the injuries seen in the hypertension. The enhanced vasodepressor PGl2 synthesis probably participates, to some extent, in these beneficial properties of long-term cicletanine treatment.
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PMID:Antihypertensive effects of cicletanine and renal protection in Dahl salt-sensitive rats. 165 82

Elevated arterial pressure in patients with obesity-hypertension is associated with an increased cardiac output and total peripheral resistance. The elevated output is related to expanded intravascular volume that increases cardiopulmonary volume, venous return, and left ventricular preload; the elevated pressure and total peripheral resistance increase afterload. This dual ventricular overload promotes a dimorphic, concentric, and eccentric hypertrophy in response to the volume and pressure overload. Increased myocardial oxygen demand results from the elevated tension in the left ventricular wall, reflecting its increased diameter and pressure, and provides physiologic rationale for the greater potential of coronary arterial insufficiency and cardiac failure. There are greater renal blood flow and lower renal vascular resistance in patients with obesity-hypertension at any level of arterial pressure. This may be offset by an increased renal filtration fraction that may favor protein deposition and glomerulosclerosis, and predisposition of obese patients for diabetes may aggravate this problem. With weight reduction, these hemodynamic derangements may be reversed: intravascular volume contracts, cardiac output decreases, and arterial pressure falls.
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PMID:Obesity and hypertension. Hemodynamic aspects. 166 10

The subtotal (5/6) nephrectomy performed in 23 adult female rats induced severe hypertrophy of residual parenchyma with interstitial fibrosis, tubular dilatation, and focal and segmental glomerulosclerosis (FSG). This ablation nephropathy (AbN) caused proteinuria, progressive renal failure, and hypertension. The extent of FSG was assessed by semiquantitative scoring. The ultrastructure revealed widespread foot process fusion, many dense cytoplasmic inclusions in podocytes, and degenerative changes or disruption of mesangium with glomerular "microcysts". Numerous granular deposits of rat Ig were seen in the glomeruli but a short praeterminal i.v. load by heat-aggregated human Ig did not alter the morphology of AbN and produced discrete and inconstant glomerular deposits. Similarly an i.v. injection of protamine and heparin generated protamine-heparin complexes seen in various layers of glomerular capillary wall, similar to those found previously in normal rats. AbN displayed a partial irregular depletion of polyanion sites reactive with polyethylenimine in lamina rara externa. A significant increase in both glomerular and interstitial Ia+ cells and a marked predominance of W3/25+ cells in the interstitial infiltrates were documented by immunohistochemistry in the remnant kidneys. Both AbN and FSG could be largely corrected (or prevented?) by subsequent syngeneic renal transplantation (TPL; 6 animals). On the other hand a severe AbN was found in two post-ablation residues after unsuccessful TPL with graft necrosis or sclerosis.--AbN has some analogies to various chronic human nephropathies (e.g. FSG) and may explain their progression to the terminal failure. Degenerative and finally destructive mesangial lesion seems to be of prime importance in AbN.
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PMID:Experimental ablation nephropathy. Fine structure, morphometry, cell membrane epitopes, glomerular polyanion and effect of subsequent transplantation. 170 Oct 48

As newer treatment modalities become available for patients with severe lupus nephritis, it becomes increasingly important to identify patients at risk for renal failure. In this study, the records of 90 children presenting with systemic lupus erythematosus over a 13-year period were reviewed. Nineteen were lost to follow-up prior to completion of the study. Of the 71 remaining children, 16 (22%) progressed to chronic renal failure. Persistent hypertension lasting greater than 4 months, anemia, abnormalities of the urinalysis, and elevated serum creatinine level were significantly associated with progression to renal failure. Sex, race, age, abnormalities of creatinine clearance, and 24-hour urine protein collection were not associated with progression to renal failure. Renal biopsies were obtained in 45 children. Biopsies were initially classified according to World Health Organization criteria. Diffuse proliferative glomerulonephritis was significantly associated with progression to renal failure. The 45 biopsies available were reviewed by one of the authors and categorized by activity and chronicity indices. Both the active lesions of fibrinoid necrosis, synechiae, tubular casts, and vasculitic lesions and the chronic lesion of glomerular sclerosis correlated with progression to renal failure. Of the 16 children who progressed to renal failure, 2 had cadaver kidney transplants and are well 5 years posttransplant; 4 had fulminant lupus and died within 1 month of commencing dialysis; 10 began chronic dialysis. Five of the 10 children on chronic dialysis died from sepsis. These data suggest that children with systemic lupus erythematosus who undergo dialysis do poorly.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lupus nephritis: prognostic factors in children. 140 32

African-Americans with essential hypertension are more prone to the development of renal failure and are frequently salt-sensitive as well. Because alterations of intrarenal hemodynamics are important in the progression of renal disease and because salt-sensitive animal models with hypertension manifest a greater propensity to develop glomerulosclerosis in association with a rise in glomerular capillary pressure, we tested whether the renal hemodynamic adaptation to high dietary Na+ intake differs in salt-sensitive and salt-resistant hypertensive patients. We studied 17 black and nine white patients with essential hypertension who were placed on a low Na+ diet (20 meq/day) for 9 days, followed by a high Na+ diet (200 meq/day) for 14 days. During the last 4 days of each diet regimen, they received 30 mg/day of slow-release nifedipine. Eleven blacks were salt-sensitive, and all whites were salt-resistant. During the low Na+ diet period, salt-sensitive and salt-resistant patients had similar mean arterial pressure, glomerular filtration rate, effective renal plasma flow, and filtration fraction.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1991 Dec
PMID:Abnormal renal hemodynamics in black salt-sensitive patients with hypertension. 174 61

The pathogenesis of progressive renal damage is most probably multifactorial. Whatever the mechanisms involved in renal disease progression, the existence of a "point of no return" has been hypothesized, that is, a stage of structural and functional damage beyond which progression of renal disease occurs independently of dietary measures and/or pharmacological treatment. In experimental animals, dietary protein and phosphate restriction is not fully successful in ameliorating the progression of functional deterioration if administered when renal injury is severe and long standing. Similarly, late treatment with various pharmacological agents (mainly antihypertensive drugs) is less effective than early administration of the same substances. A serum creatinine of 176 mumol/L seems a critical point discriminating the results of either dietary protein and phosphate restriction or antihypertensive treatment in patients with chronic renal disease. The protective effects of both dietary and nondietary intervention seem to be most effective when at least 50% of the residual renal mass is still functioning. The extent to which glomerular sclerosis, vascular hyalinosis, and interstitial fibrosis have already developed can probably blunt or avert the expected results of treatment. Some clinical tests may identify those patients who would benefit from measures such as the reduction in glomerular hemodynamic stress, the long-term inhibition of the renin-angiotensin system, and the aggressive treatment of systemic hypertension. The continuous search for a rational preventive treatment before the disease process has reached the "point of no return" will undoubtedly constitute a formidable task for the modern nephrologist.
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PMID:Is there a "point of no return" in progressive renal disease? 175 86


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