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G Nascimento

Publications and source records attributed to G Nascimento.

5 recordsLinked to original sources
PubMed1988

Aminoglycoside and nephrotoxicity.

The effect of three aminoglycosides--gentamicin, netilmicin and amikacin--on renal acid excretion was studied in male rats treated with doses equivalent to those clinically used. The amikacin and netilmicin groups showed no important changes in the values of glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and U/P inulin ratio during normal and acidotic conditions. The gentamicin group, however, showed a clear tendency to decreases in these functional parameters even in normal conditions, a finding that reinforces the concept that gentamicin is more nephrotoxic than other aminoglycosides. During normal conditions net acid excretion (BH) did not change with any of the three tested drugs. However, after an acute acid load BH markedly fell regardless of the antibiotic used. The capacity to elevate the urine-blood pCO2 was preserved after an alcaline overload, suggesting that the distal tubule was not significantly affected by aminoglycoside treatment. These data suggest that the clinical use of aminoglycosides during metabolic acidosis deserves close attention due to the possible deleterious effect that can emerge as the result of an inappropriate retention of acid loads.

Amikacin↗
PubMed1987

Evaluation of distal tubular function in aminoglycoside-induced nephropathy.

Acute metabolic acidosis potentiates the nephrotoxicity of aminoglycosides by impairing the adequate excretion of ammonium and titratable acidity. The present study assesses distal tubular function after aminoglycoside administration in the rat. Two aminoglycosides, gentamicin and netilmycin were given to rats either in low doses equivalent to those used clinically (BG4 and BN5 groups) or in doses ten times higher (BG40 and BN50). The rats were subjected to acute metabolic alkalosis and the pCO2 of urine was continuously evaluated. The regression lines obtained by plotting the differences between urine and blood pCO2 as a function of urinary HCO3- in low dose models were similar to those obtained for the control group. However, the slopes obtained for BG40 and BN50 were significantly different from the control, suggesting an impairment of H+ secretion.

Acidosis, Renal Tubular↗
PubMed1986

Effect of gentamicin on urinary acidification in the rat.

The effect of gentamicin, an aminoglycoside antibiotic, on renal function and especially on acid excretion was studied in normal and acidotic rats. The doses used were 1 (G4) and 10 (G40) times the suggested human therapeutic dose on a weight basis. After 10 days of each treatment, the glomerular filtration rate (GFR) was unchanged in G4 but fell significantly (p less than 0.05) in G40. In the acidotic groups (AG4 and AG40) there was an accentuated reduction in GFR, renal plasma flow and urine/plasma insulin ratio. Normal rats showed a normal acid excretion even with the high-dose treatment but, in the acidotic group, there was a significant decrease in ammonia excretion. The amount of bicarbonate excretion was significantly elevated in those groups, leading to a greater urinary pH. These results indicate that acute metabolic acidosis enhanced the nephrotoxic effects of gentamicin and impaired the excretion of an acid overload.

Ammonia↗
PubMed1986

Aminoglycosides and renal acid excretion.

The effect of three aminoglycosides, gentamicin, netilmicin and amikacin, on renal acid excretion was studied in rats treated with doses equivalent to 10 times those used clinically. The gentamicin and amikacin groups showed a marked decrease (P less than 0.05), in glomerular filtration rate (GFR), U/P inulin ratio and renal plasma flow (RPF), while in the normal acid-base state. Under acidotic conditions, only gentamicin promoted significant alterations in GFR and RPF. Net acid excretion as measured by the acid balance (BH) was calculated as the sum of ammonium excretion (NH4+) and titratable acidity (AT) minus the amount of excreted bicarbonate (CHCO3-). Under normal conditions, netilmicin promoted a considerable fall in both NH4+ and AT, which led to a significant decrease in BH, whereas no changes were observed in these parameters with the other two drugs. In contrast, during acute metabolic acidosis, all tested antibiotics promoted a marked fall in BH, particularly due to a significant decrease in NH4+ and AT. These data suggest that the effects of aminoglycoside treatment during acute metabolic acidosis in clinical practice deserve further study in view of possible deleterious effects on the clinical state.

Acidosis, Renal Tubular↗