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In the present study we investigated the effect of a single dose, and 3 months of treatment with spirapril on kidney function, renin-angiotensin system, renal handling of sodium and blood pressure, in patients with reduced kidney function (serum creatinine 1.5-3 mg%) and hypertension. A single dose of 6 mg spirapril given at the beginning of the study did not affect glomerular filtration rate (GFR), renal plasma flow (RPF), angiotensin converting enzyme (ACE) activity, plasma renin activity (PRA) or renal handling of sodium. When the single dose of spirapril was given after 3 months of treatment with this agent, renal hemodynamics and PRA did not change. ACE activity, which was depressed by the previous spirapril treatment, decreased further (from 9.5 +/- 3.1 to 1.4 +/- 1.0 nmol/ml/min), (p < 0.05). Administration of 6 mg spirapril o.d. for 3 months did not have any effect on GFR or RPF. Serum ACE activity decreased from 92.1 +/- 8.0 to 5.1 +/- 2.6 nmol/ml/min (p < 0.05) and PRA increased from 1.4 +/- 1.2 to 4.1 +/- 3.6 ng/ml/min (p < 0.05). Plasma aldosterone did not change. Similar results were obtained when spirapril was combined with 5 mg isradipine in the initial and final single dose, or in the 3 months' treatment (5 mg o.d.). Blood pressure was normalized in 38% of the patients who received spirapril and in 71% of the patients who received spirapril and isradipine. Thus, (a) treatment with spirapril in patients with mild to moderate chronic renal insufficiency was not associated with deleterious effects on kidney function; (b) spirapril in a dose of 6 mg alone or in combination with 5 mg isradipine is effective in reducing blood pressure in hypertensive patients with reduced kidney function.

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The hypertrophy of the remaining kidney following uninephrectomy (UNx) has been related to an increase in renal insulin growth factor-I (IGF-I) content. However, while the increase in renal IGF-I lasts for only days after UNx, renal hypertrophy continues for months. In the present study we investigated whether IGF-I also plays a role in the late post uninephrectomy growth of the remaining kidney. Renal IGF-I in the remnant kidney was greater than that of control kidneys (78.3 +/- 17.3 vs 56.0 +/- 14.0 pmol g-1; p < 0.05) 3 days after UNx, tended to remain higher 30 days after UNx (83.8 +/- 23.6 vs 57.3 +/- 14.5 pmol g-1; p = 0.07), but was similar to that of the control kidney when examined 60 days after UNx (66.6 +/- 15.6 vs. 70.4 +/- 6.7 pmol g-1). Serum IGF-I in uninephrectomized rats was similar to that of controls 3 days after UNx, started to increase above the control level at day 10 after UNx and remained higher 30 and 60 days after UNx (75.9 +/- 6.9 vs. 48.7 +/- 7.3 nmol l-1 at 30 days, and 81.2 +/- 13.7 vs 52.9 +/- 11.0 nmol l-1 at day 60, p < 0.05 for both). The kidney weight of uninephrectomized rats was higher by 21% than that of controls 3 days after UNx, by 45% 30 days after UNx and by 63% 60 days after UNx (p < 0.05 for all three observations). At the end of the study, the glomerular volume of uninephrectomized rats was higher by 36% than that of the controls (p < 0.05) We suggest that in the rat, while the initial post uninephrectomy hypertrophy of the remnant kidney is associated with and most probably mediated by an increase in renal IGF-I, the hypertrophy that persists in later post UNx periods is associated with and may be mediated by an increase in serum IGF-I.

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Animal studies have shown that a 4-6-fold increase in serum cholesterol aggravates pre-existing renal injury. We studied the renal effects of moderate hypercholesterolaemia over a period of 18 weeks in uninephrectomized rats. Animals were allocated to two groups; the group 1 rats were fed a normal diet, as controls, and the group 2 rats were fed a high cholesterol diet containing 3% cholesterol and 1% sodium cholate by weight. The serum total cholesterol was higher in group 2 than in controls being 2.5 +/- 0.4 vs. 1.0 +/- 0.1 mmol l-1 at 9 weeks and 2.1 +/- 0.3 vs. 1.1 +/- 0.2 mmol l-1 at 18 weeks (p < 0.05 for both). Serum high density lipoprotein cholesterol levels were similar in both groups. The mean systolic blood pressure was higher in group 2 than in controls, at 145 +/- 9 vs. 137 +/- 8 mmHg (p < 0.05) by 13 weeks and 146 +/- 6 vs. 136 +/- 4 mmHg (p < 0.05) at 18 weeks. Serum creatinine and glomerular filtration rates were similar in both groups. Urine protein excretion remained within the normal range in both groups. Histological examination at 18 weeks showed diffuse fatty changes in the liver cells and prominent vacuolization of renal tubule cells in the group 2 rats. Nevertheless, the glomeruli were normal. There was no significant difference in mean glomerular volume between group 2 rats (1.20(-3) +/- 0.09(-3) mm3) and controls (1.36(-3) +/- 0.10(-3) mm3). Thus moderate hypercholesterolaemia for 18 weeks in uninephrectomized rats resulted in a mild elevation in blood pressure, but did not affect glomerular volume or glomerular histology, in spite of the deleterious effects on liver and renal tubule cells. We assume that extremely high levels of serum cholesterol are required to induce glomerulosclerosis in the rat.

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Antihypertensive treatments were given to young and adult SHRs, to prevent and reverse hypertension, respectively. Cardiac hypertrophy and the steady state level of the "fetal" genes, ANP, alpha-skeletal actin (alpha-skA), and beta myosin heavy chain (beta-MHC) mRNAs were assessed. Our findings show that the reduction of blood pressure does not consistently result in a similar regression of the "fetal gene program".

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Angiotensin-converting enzyme (ACE) inhibitors may cause a further decrease in renal function in patients who already have renal failure. The acute effects of the ACE inhibitor spirapril on renal function were investigated in 10 patients with mild-to-moderate renal failure (serum creatinine of 1.5-2.5 mg/dl). Acute oral administration of spirapril at 6 mg resulted in decreases in inulin clearance (from 53.7 +/- 12.8 to 44.6 +/- 8.8 ml/min; p < 0.02; n = 5) and in PAH clearances (from 215 +/- 141.9 to 184 +/- 37.8 ml/min; p < 0.006; n = 5). However, when the acute administration of 6 mg of spirapril was given concomitantly with isradipine at 5 mg, there were no changes in these renal function parameters.

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The purpose of this review has been to summarize the effects of lipids on the progression of renal disease in chronic renal failure. Animal studies show that hypercholesterolemia as induced by a high cholesterol diet can aggravate the progression of renal disease in experimental models of chronic renal failure. Hypolipidemic treatment, when given to animals with chronic nephropathy associated with endogenous hyperlipidemia such as in reduced renal mass, obese Zucker rat, PAN nephrosis and the Dahl salt-sensitive rat, results in a reduction in serum lipids levels concomitant with a decrease in the renal damage. Enrichment of the diet with omega-6 PUFA given to rats with reduced kidney mass leads to a reduction in renal damage, probably due to beneficial changes in renal fatty acid composition, while supplementation of a fish oil diet to rats with immune complex nephritis resulted in a similar beneficial effect, probably due to a suppression in the local immunologic processes. The pathogenesis of this effect is still only partially understood. Lipid deposition and oxidation in the renal mesangium, migration of circulatory monocytes into the renal mesangium and their transformation to foam cell, and alterations in renal PUFA metabolism and composition are the main known alterations that accompany lipid-induced renal damage. These alterations, which are similar to those observed in atherosclerosis, lead to alterations in the normal biologic processes in the renal mesangium and terminate in glomerulosclerosis. Extrapolating the data from experimental studies to human renal diseases, it may be assumed that lipid metabolism has a significant impact on the gravity and progression of renal disease in a selected patient population, namely in patients with chronic renal disease. If so, hypolipidemic treatment or administration of certain types of PUFA can be important in the prevention of progression of the renal disease in these patients. Clinical studies are needed to elucidate this issue.

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The causes of death in 84 end-stage renal failure patients, treated with dialysis, who died during a 66-month period were reviewed retrospectively. Cardiac and infectious diseases were the main cause of death (27% each). These two constituted 44% of causes of death in hemodialysis and 75% in continuous ambulatory peritoneal dialysis patients. Malignant disease (7%) and hyperkalemia (5%) were responsible for death only in hemodialysis patients. Patients who died following hyperkalemia were younger than 50 years old. Patients who died from malignant disease were dialyzed for more than 3 years. In summary, the mode of dialysis therapy, age at start of therapy, time on dialysis, and previous cardiac disease may play a role in determining the causes of death in dialysis patients.

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The immediate (1 day, D1) and late (90 days, D90) effects of unilateral nephrectomy on contralateral renal hemodynamics, and the renal handling of electrolytes and water were investigated in the whole animal. The immediate and late ability of the remnant kidney to autoregulate perfusate flow and glomerular filtration rate (GFR) was studied in the isolated perfused kidney of the rat. In the whole animal, in D1 rats as compared to controls, GFR calculated for a single kidney increased from 0.85 +/- 0.3 to 1.1 +/- 0.2 ml/min (p less than 0.05). In D90 rats GFR increased further and was similar to prenephrectomy GFR (1.4 +/- 0.5 vs. 1.7 +/- 0.5 ml/min, p NS). Urinary prostanoid excretion in 24 h, calculated for one kidney, increased by 50-500% in D1 rats, but returned to prenephrectomy values in D90 rats. In the isolated perfused kidney, decreasing perfusion pressure (PP) from 100 to 70 mmHg did not change the renal vascular resistance (RVR) in control and D90 kidneys, but in D1 kidneys RVR decreased from 8.6 +/- 1.3 to 7 +/- 1.3 mm Hg/ml/min (p less than 0.05). In D90 kidneys RVR was significantly lower as compared to control and D1 kidneys at all perfusion pressures. Decreasing PP from 100 to 70 mm Hg resulted in a significant decrease in perfusion flow in control, D1 and D90 kidneys, while with the increase in PP from 100 to 130 mm Hg the perfusion flow increased significantly in all three kidney groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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At present the pathogenesis of diabetic nephropathy remains unresolved. Clearly lack of insulin, with its associated disorders of carbohydrate, protein, and/or lipid metabolism, initiates the process which eventually leads to the characteristic histologic picture of diabetic nephropathy. The disturbance in cellular metabolism per se could directly injure the kidney by altering the energy needs of the cell or by leading to the accumulation of cellular toxins (ie, polyols) or by causing the deficiency of key cellular metabolites (ie, myoinositol). Elevation of the plasma glucose concentration enhances the glycosylation of proteins, which in turn can lead to glomerular basement membrane thickening, loss of charge selectivity, and direct cellular damage. The multiple disturbances in intermediary metabolism are associated with increased levels of and/or enhanced sensitivity to a variety of growth factors, including IGF-I and angiotensin, and this could lead to glomerular hypertrophy. An increase in the filtered load and subsequent reabsorption of electrolytes and metabolites also could contribute to renal hypertrophy. In all animal models of nephropathy, including diabetes, glomerular hypertrophy has been shown to be the best correlate of glomerular sclerosis, proteinuria, and progressive renal deterioration. The potential mechanisms by which glomerular hypertrophy can lead to renal histologic damage were discussed previously. By increasing the luminal diameter, glomerular hypertrophy also would be expected to augment wall tension and thereby increase intraglomerular pressure. Derangements in cellular metabolism or altered sensitivity to angiotensin also can directly elevate the intraglomerular pressure and lead to structural renal damage. In this schema, elevated intraglomerular pressure is but one of many pathogenic factors that contribute to the development of diabetic glomerulopathy and albuminuria. The precise role of increased glomerular pressure in the evolution of diabetic nephropathy remains uncertain at present. In rats, severe diabetic nephropathy can occur without an increase in Pgc, while in humans, hyperfiltration does not appear to be a predictor of proteinuria and renal dysfunction. Lastly, it is likely that a variety of other factors, including the coagulation system, plasma/cell lipid levels, prostaglandins, etc, also play a role in the pathogenesis of diabetic nephropathy. According to the outline presented in Figure 1, it is unlikely that any single factor will be sufficient to explain the development of diabetic glomerulosclerosis. Ultimately, the origin of diabetic nephropathy in IDDM must be traced to insulin lack, with its associated derangements in cellular metabolism. Therefore, the importance of tight glucose control should not be underemphasized.(ABSTRACT TRUNCATED AT 400 WORDS)

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The effect of specific amino acid groups on renal hemodynamics was examined in seven healthy young volunteers. Each subject received a 3-h intravenous infusion according to one of the following protocols: study 1, gluconeogenic amino acids (Arg, Gly, Pro, Cys, Met, Ser); study 2, alanine alone; study 3, branched-chain amino acids (BCAA, Leu, Ile, Val); or study 4, 0.9% saline. The rise (40-60% above base line) in total plasma amino acid concentration was similar in studies 1-3; no change was observed in study 4. During study 1, glomerular filtration rate (GFR) rose by 16% (from 98 +/- 6 to 114 +/- 8 ml.1.73 m-2.min-1, P less than 0.01), and renal plasma flow (RPF) rose by 28% (from 496 +/- 47 to 638 +/- 70 ml.1.73 m-2.min-1, P less than 0.01). After alanine (study 2) and BCAA (study 3) infusion, there was a slight, although not significant, rise in GFR and RPF; during saline infusion (study 4), GFR and RPF remained unchanged. Plasma insulin and growth hormone did not change significantly in any study protocol. Plasma glucagon rose significantly by 30% in study 1 (from 117 +/- 10 to 151 +/- 13 pg/ml, P less than 0.05) but did not change in studies 2-4. In summary, infusion of mixed gluconeogenic amino acids increases both GFR and RPF, and neither alanine nor BCAA infusion caused a consistent alteration in renal hemodynamics.

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Bopindolol was given to hypertensive patients in a single daily dose ranging from 1 to 4 mg. In 86.7% of the patients diastolic blood pressure was reduced by 10 mmHg or more, or lowered to below 90 mmHg, already during the first 4 wk of treatment. Inulin clearance decreased by 10%; PAH and creatinine clearance, blood urea nitrogen, and serum creatinine were unchanged.

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In the present study the possible role of endogenous prostaglandins in modulating the renal effects of angiotensin II was investigated in the isolated perfused rat kidney. Angiotensin II (5 ng/ml) caused both an increase in prostaglandin E2 synthesis and an increase in renal vascular resistance, as well as an increase in perfusate flow rate and glomerular filtration rate. Filtration fraction did not change. Inhibition of prostaglandin synthesis did not influence these effects of angiotensin II. In addition, angiotensin II caused natriuresis and to a lesser degree kaliuresis. These effects were independent of intrarenal hemodynamic effects. Inhibition of renal prostaglandin synthesis did not have any effect on the angiotensin-induced natriuresis. We conclude that the natriuretic effect of angiotensin II is independent of renal prostaglandin synthesis.

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Herniae are a common complication of treatment with continuous ambulatory peritoneal dialysis (CAPD). The diagnosis is often difficult because the hernia may not be apparent, or because the symptoms may mimic peritonitis or other severe abdominal complications. This report describes the occurrence of intestinal incarceration in an occult incisional hernia in two CAPD patients. The possibility of this diagnosis must be considered in CAPD patients complaining of severe abdominal pain.

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Acute reversible renal failure has been reported in patients receiving captopril, especially those with unilateral or bilateral renal artery stenosis. Two patients with advanced renal disease presented with an acute deterioration in renal function after the introduction of captopril treatment. In both instances this deterioration was irreversible. Captopril should be used with caution in patients with advanced renal disease.

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Thirty-five patients treated with continuous ambulatory peritoneal dialysis (CAPD) were followed over a 2-yr period. Serum levels of protein metabolites were maintained at stable and satisfactory levels. Blood hemoglobin was higher during CAPD treatment than during hemodialysis. At the end of the follow-up period, 45.7% of the patients were still on CAPD, 25.7% of them had been transferred to another mode of dialysis because of complications, and 28.6% of the patients had died. In half of the latter, death was directly related to CAPD. The high incidence of peritonitis (one infection per 2.4 patient months) is the main drawback and reason for mortality in CAPD. Reduction in the incidence of peritonitis would make CAPD the preferred mode of dialytic therapy.

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Beta-adrenergic blockade by oral propanolol in five cirrhotic patients caused changes in the handling of an acute sodium load. Fractional sodium excretion following an acute saline load increased from 0.69% +/- 0.29 to 1.49% +/- 0.11 (103 microEq/min +/- 7.5 to 129 microEq/min +/- 18) before propranolol administration. After 3 days of oral propanolol 1 mg/kg day, the fractional excretion of sodium by saline loading increased from 0.52% +/- 0.19 to 2.17 +/- 0.19 (109 microEq/min +/- 9 to 178 microEq/min +/- 11). This change was not accompanied by changes in GFR, RPF or in the renin-aldosterone system. The possibility that these changes are caused by a change in the sodium transport at the tubular cell level induced by the beta-adrenergic blockade, is entertained.

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