Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Up to now, no studies have been performed in normal humans to investigate the role of renal hemodynamic abnormalities in relation to acute-cyclosporin A (CsA) renal dysfunction and to verify whether the specific renal vasodilator, dopamine, can counteract these abnormalities. Eight normal subjects were examined both (A) after oral CsA (12 mg/kg body wt) and (B) after oral CsA + dopamine infusion (2 mg/kg body wt/min), under water diuresis. Both in protocols A and in B, four basal renal clearances were performed before CsA and every twenty minutes for four hours after CsA administration. In protocol A, after CsA, inulin (GFR) and PAH clearance (RPF) fell by up to 27% and to 41%, respectively, so that filtration fraction (FF) increased (P less than 0.01). A slight (not significant) hypertension occurred while renal resistances were markedly raised (P less than 0.001). Fractional urine and Na+ excretion as well as CH2O decreased, while UOsm increased (P less than 0.01). In protocol B, dopamine was infused from 120 to 180 minutes after CsA (that is, when the maximal adverse effects of CsA on renal hemodynamics had been observed in A). Dopamine infusion could reverse completely the effects of CsA on RPF, GFR, fractional urine output and CH2O; only UOsm remained higher than normal in conclusion with an increased fractional excretion of sodium (P less than 0.01). No changes were observed in plasma renin activity, aldosterone and in urinary epinephrine and norepinephrine excretion both in protocols.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Acute cyclosporine renal dysfunction reversed by dopamine infusion in healthy subjects. 260 Dec 57

Serial calculations of glomerular filtration rate were made in 31 pediatric liver transplant recipients surviving more than 1 year. GFR was computed from the Schwartz formula, (cGFR = KL/S Cr), before orthotopic liver transplantation, and at 3-6 monthly intervals thereafter. At the same time points, CsA dose/kg, CsA level, blood pressure, and liver functions were recorded. The mean difference between the pre-OLT cGFR and the most-current cGFR for all patients was -50 ml/min/1.73 m2 (P = less than 0.005). In 17/31 (55%), the current cGFR was less than 80 ml/min/1.73 m2, indicative of renal impairment. The cGFR continued to decrease in 24 patients followed beyond 1 year (26.8 ml/min/1.73 m2 per year decrease, P less than 0.005). More patients with a cGFR less than 80 ml/min/1.73 m2 had outpatient hypertension. There was no correlation of cGFR with CsA levels, CsA dose, or liver function. We conclude that a significant decrease in cGFR is seen in children treated with CsA for more than 1 year, which is progressive in the majority.
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PMID:Serial decrease in glomerular filtration rate in long-term pediatric liver transplantation survivors treated with cyclosporine. 264 18

In patients with well-functioning renal allografts, the presence of diseased native kidneys appears to be a common cause of elevated blood pressure. We evaluated the role of native kidneys in post-transplant hypertension using a rat model in which the confounding variables of rejection and immunosuppression could be eliminated. To produce disease in native kidneys. PVG rats were subjected to 5/6 nephrectomy. Four weeks following renal ablation, these hypertensive animals were transplanted with kidneys from syngeneic PVG donors. Four weeks later, the effects of captopril and native nephrectomy on blood pressure and renal hemodynamics were examined. Animals with remnant native kidneys which received non-rejecting renal isografts had sustained hypertension, elevated plasma renin levels and reduced transplant function. In these animals, administration of captopril reduced systemic blood pressure. Despite the reduction in blood pressure, PAH clearance by the transplanted kidney increased markedly while GFR rose modestly. Removal of the remnant native kidney also acutely lowered blood pressure. However, compared to captopril, native nephrectomy produced a more marked increase in GFR without significantly affecting renal blood flow. In this model of post-transplant hypertension in the rat, elevated blood pressure and reduced isograft function are mediated by the diseased native kidney, in part through the effects of angiotensin II. These data suggest that ACE inhibitors and native nephrectomy may have beneficial hemodynamic effects in patients with post-transplant hypertension caused by native kidneys.
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PMID:Post-transplant hypertension in the rat: effects of captopril and native nephrectomy. 268 27

Cyclosporine-treated renal allograft recipients frequently suffer CsA-related nephrotoxicity and hypertension. This study demonstrates that glomerular filtration rate is reduced acutely by 13% (P less than 0.02) and renal vascular resistance increased by 30% (P less than 0.05), immediately after patients take their CsA dose. The reduction in GFR is directly related to their trough CsA level (r = 0.82; P less than 0.01). The lower the trough CsA level the greater the fall in GFR after the CsA dose. Plasma renin activity does not increase after the CsA dose (pre-CsA 0.6 +/- 0.2 ng/L/sec vs. post-CsA 0.4 +/- 0.1 ng/L/sec; P = NS), and therefore cannot be responsible for the reduction in renal function. Short-term nifedipine treatment is effective in preventing the acute reduction in GFR (P less than 0.05). This occurred despite no apparent effect of nifedipine in altering trough or post-dose CsA levels. Furthermore nifedipine was effective in lowering both the mean arterial blood pressure (109 mmHg to 94 mmHg; P less than 0.01) and the elevated renal vascular resistance (25% reduction; P less than 0.02) observed in these patients. These results suggest that nifedipine may be a suitable agent for limiting acute CsA nephrotoxicity and for treating CsA-associated hypertension in renal allograft recipients.
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PMID:Cyclosporine-induced renal dysfunction in human renal allograft recipients. 268 8

Many different classification systems for Ca2+ antagonists were proposed. They are mostly based on structural aspects or profiles of biological activity. 1,4-dihydropyridines, with Ca2+ channel antagonistic activity, including nifedipine and nitrendipine, are highly effective as antihypertensive agents. Although Ca2+ antagonists have multiple sites of antihypertensive action, their main mechanism of action is inhibition of Ca2+ entry into the vascular smooth muscle cells. Ca2+ channel antagonists bind to specific receptors at Ca2+ channels and stabilize the channels in a mode unavailable for opening. Their effect is enhanced by depolarization of the cell membrane. Currently used pharmacological methods for detection of Ca2+ antagonistic action of drugs include: (1) inhibition of 45Ca2(+)-uptake; (2) displacement of [3H]nitrendipine from isolated membranes, and (3) inhibition of Ca2+ current in single cells or channels. Ca2+ antagonists were reported to prevent hypertension-induced vascular changes and other vascular pathology, probably related to Ca2+ overload. Vascular lesions in Dahl salt-sensitive hypertensive rats and in spontaneously hypertensive rats were prevented by chronic administration of nifedipine or nitrendipine. Hemodynamic effects of Ca2+ antagonists are characterized by reduction in total peripheral vascular resistance, increase in cardiac output, reduction in systemic left ventricular end-diastolic, pulmonary arterial and capillary wedge pressures. Ca2+ antagonists differ in potency, duration of action and their therapeutic ratios. DHPs enhance sympathetic tone and have little or no negative dromotropic action. They are, therefore, safer in combination with beta-adrenoceptor antagonists than either verapamil or diltiazem. In comparison with other Ca2+ antagonists nitrendipine is highly potent as a vasodilator. As a negative inotropic agent, it is, however, less potent than either verapamil or nifedipine. Nitrendipine has, therefore, a better therapeutic ratio than some of the other well-known Ca2+ antagonists. Unlike older vasodilators, e.g. hydralazine and minoxidil, Ca2+ antagonists have diuretic properties which are primarily due to inhibition of tubular reabsorption of salt and water. Under certain experimental conditions, e.g. infusion of angiotensin II, DHPs can increase GFR. Nitrendipine has also renal cytoprotective activity. It protected rats from aminoglycoside-induced nephrotoxicity and antagonized proliferative glomerular changes in nephritic rats.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Pharmacological basis for use of calcium antagonists in hypertension. 269 46

This paper reviews experimental findings which support the concept that vasopressin (VP) and the process of urine concentration may be involved in the progression of chronic renal failure (CRF). The influence of dietary protein intake on the progression of CRF may also involve VP and the operation of the concentrating process. VP receptors have been identified in glomeruli and VP is able to constrict mesangial cells as does angiotensin II. Acute VP infusion increases the glomerular transcapillary hydraulic pressure difference, and chronic VP infusion increases GFR. In rats with CRF (induced by 5/6 nephrectomy), VP levels were found elevated. In rats with 5/6 nephrectomy, we increased experimentally water intake in order to decrease circulating VP levels, urine concentration, and free water reabsorption. Several indices of progression of CRF, including proteinuria, hypertension and glomerulosclerosis, were significantly reduced, thus suggesting a contribution of VP in progression. Lowering protein intake in CRF could be beneficial because proteins, but not carbohydrates or lipids, produce metabolic end products (mainly urea, ammonia, protons, etc.) that are excreted by the kidney, and concentrated in the urine. In healthy subjects (man or rat), high protein (HP) intake favors urine concentration and causes changes in kidney function and morphology very similar to those induced by chronic VP infusion or water restriction. These changes involve an increase in transport activity of the thick ascending limb (where the initial active step of the concentrating process takes place) and may affect filtration rate and/or glomerular hemodynamics secondarily, by decreasing salt concentration at the macula densa and depressing tubuloglomerular feedback.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Possible involvement of vasopressin and urine concentrating process in the progression of chronic renal failure. 270

Much clinical evidence supports the use of angiotensin-converting enzyme inhibitors (ACE-I) as the first-step drugs in the treatment of essential hypertension. The acute and chronic effects of ACE-I on renal function are reviewed in this paper. The kidney is an important target organ of essential hypertension and some antihypertensive drugs have been shown to decrease renal haemodynamic parameters. In hypertensives with normal renal function, ACE-I were demonstrated to be safe drugs: after acute and chronic administration of these drugs, the drop in blood pressure was accompanied by unchanged or increased GFR and RPF, with decreased renal vascular resistance. Only in patients with renovascular hypertension, with bilateral stenosis or solitary kidney, was there a deterioration in renal function.
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PMID:ACE inhibitors: antihypertensive treatment and renal function. 270 Mar 23

To evaluate the significance of tubulointerstitial lesions in the cortical area of renal biopsy specimens, clinicopathological studies were performed on 101 cases of IgA nephropathy, 31 cases of IgA-negative (non-IgA) proliferative glomerulonephritis and 75 cases of idiopathic membranous glomerulonephritis. The degree of tubulointerstitial lesions was assessed semiquantitatively by light microscopic observation and was correlated with the several histopathological and clinical parameters at biopsy, as well as with status at final follow-up (average follow-up period: 72 months). In these three types of glomerulonephritis, the degree of tubulointerstitial lesions in the cortical area was clearly correlated with the severity of glomerular injury, the prevalence of segmental sclerosis, global sclerosis, arteriolosclerosis, decreased renal function (GFR less than 70 ml/min) and hypertension (greater than 150/90 mm Hg) at the time of biopsy. The prevalence of stable renal function at final follow-up was statistically higher in the cases without tubulointerstitial lesions or with those whose lesions included less than 20% of the cortical area. From the above data, it was concluded that a semiquantitative evaluation of tubulointerstitial lesions in the cortex would reflect the severity of glomerular injury and also contribute to the assessment of prognosis in such primary glomerulonephritic patients.
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PMID:Significance of tubulointerstitial lesions in biopsy specimens of glomerulonephritic patients. 271 60

This study examines renal function in different rat models of renovascular hypertension. Hypertension was induced by constriction of the aorta proximal to the renal artery (PAC), by PAC and nephrectomy (PAC + Nx) or by renal artery stenosis (RAS). PAC + Nx is equivalent to the Goldblatt 1 kidney-I clip hypertension model. The PAC rats were studied 3 weeks after surgery. Hypertension was by then well established. GFR, measured as the clearance of inulin, was significantly lower in PAC rats than in control (C) rats. GFR was the same in PAC + Nx rats as in C rats, but significantly lower in PAC + Nx than in Nx rats. Kidney weight was significantly higher in PAC + Nx rats than in C rats. Filtration fraction (FF), measured as the ratio between GFR and the clearance of PAH, was significantly higher in PAC and PAC + Nx rats than in C and Nx rats. In RAS rats hypertension was not established until 6 weeks after surgery, and RAS is equivalent to Goldblatt 2 kidney-I clip hypertension. Renal artery constriction was moderate as judged from the weight ratio between the stenosed and contralateral kidneys. The GFR in the stenosed kidney was not significantly lower in the contralateral kidney. FF was significantly higher in RAS rats than in C rats in both the stenosed and the contralateral kidneys, but the increase was less pronounced than in PAC and PAC + Nx rats.
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PMID:Renal function in different forms of renovascular hypertension in rats. 275 May 42

Lisinopril is a new, long-acting, nonsulfhydryl angiotension-converting enzyme (ACE) inhibitor that is excreted unchanged by the kidney. The antihypertensive efficacy and safety profiles of lisinopril were assessed in 24 patients (15 men, 9 women; mean age 52.3 years; range 21-75 years) with hypertension associated with impaired renal function (glomerular filtration rate GFR 60 ml/min or less), in an open study of 12 weeks' duration. Previous antihypertensive drugs were discontinued at entry into the study. Lisinopril was given orally once daily; the starting dose was 2.5 mg in patients with a GFR of less than 30 ml/min, and 5 mg in all other patients. The dosage of lisinopril was titrated upward to 40 mg daily according to BP response. A diuretic could then be added if hypertension was inadequately controlled. Twenty-three patients completed the study. Mean sitting BP was reduced from 177 +/- 21.2/106 +/- 9.1 mm Hg (mean +/- SD) at entry to the study to 145 +/- 21.4/88 +/- 8.3 mm Hg after 12 weeks of treatment (p less than 0.001). The median dose of lisinopril used was 10 mg (range 2.5-40 mg) and only 4 patients had a diuretic added to the lisinopril. Overall GFR was unchanged during the study: mean baseline value was 37 +/- 16.4 ml/min (range 10-60 ml/min) at the beginning of the study and 40 +/- 21.0 ml/min at the end. As in a previous pharmacokinetic study in similar patients, a tendency toward drug accumulation was noted only in those patients with the most severe renal impairment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lisinopril treatment of hypertension in patients with impaired renal function. 283 Nov 15


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