Further studies on the in vivo effect of cephaloridine on the stability of rat kidney lysosomes

Alkaline phosphatase activities following repeated suramin administration in some rat tissues in relation to their functions

The effect of repeated administration of suramin, a trypanocide and filariacide, on the level of alkaline phosphatase activity in some rat tissues and organs was investigated. Daily administration of this drug to rats resulted in a very significant increase in enzyme activity in the kidney and small intestine immediately after the first dose. Activity observed in the liver was not affected until after the third dose when the level was increased. In the heart and the large intestine, administration of the drug did not affect the enzyme activity levels throughout the duration of drug administration. These results suggest that repeated suramin administration may result in very large increases in alkaline phosphatase activity in the tissues and organs which are involved in active transport mechanisms.

The influence of cephem antibiotics on gentamicin nephrotoxicity in normal, acidotic, dehydrated, and unilaterally nephrectomized rats

Normal, acidotic, dehydrated, or unilaterally nephrectomized rats (Sprague-Dawley) were injected with gentamicin (80 mg/kg/day) alone or in combination with cefoxitin (2 g/kg/day), cephalothin (2 g/kg/day), or cephaloridine (1 g/kg/day) once daily for 10 consecutive days. Serum creatinine levels and renal cortical concentrations of gentamicin were determined and histopathological examination of the kidneys was made. Gentamicin caused marked renal damage in all the groups of rats. In normal rats, all the cephem antibiotics significantly reduced both gentamicin nephrotoxicity and renal gentamicin levels. In acidotic, dehydrated, and unilaterally nephrectomized rats, cefoxitin still significantly reduced gentamicin nephrotoxicity without affecting renal gentamicin concentration, whereas cephalothin and cephaloridine did not show any significant reduction of nephrotoxicity or gentamicin concentration, but rather caused general deterioration of the animals. Hence, the intrinsic nephrotoxic potential of cefoxitin, cephalothin, and cephaloridine may contribute to the difference in the combined effect rather than the concentration of gentamicin in the kidney.

Studies on the nephrotoxicity of aminoglycoside antibiotics and protection from these effects (3). Protective effect of latamoxef against tobramycin nephrotoxicity and its protective mechanism

Effect of latamoxef (LMOX) against tobramycin (TOB)-induced nephrotoxicity was studied in rats. Treatment with TOB (90 mg/kg/day, s.c.) alone resulted in marked increases in the activities of urinary enzymes such as lactate dehydrogenase, N-acetyl-beta-D-glucosaminidase and lysozyme, urinary protein content and blood urea nitrogen, which peaked on the 7th or 10th day. The combination with LMOX (500, 1000 or 2000 mg/kg/day, s.c.) significantly suppressed increases in the parameters with TOB alone. The extent of this suppression roughly depended on the LMOX dosage. Although TOB alone caused pronounced histological changes such as extensive cortical proximal tubular cell necrosis, residual tubular basement membrane and cast formations in the renal cortex and medulla on the 7th day, these changes were apparently suppressed by combination with LMOX. In addition, intrarenal TOB concentrations in the rat given TOB alone were about 350, 500 and 1000 micrograms/g tissue wet weight at 3 hr, on day 3 and on day 5, respectively. On the other hand, there was a significant reduction (30-60%) in intrarenal TOB concentration by combination with LMOX. These results indicate that combination with LMOX obviously protects the rat kidney from TOB nephrotoxicity, and the protective effect may be partially due to suppression of intrarenal accumulation of TOB by LMOX.

Chloroquine-induced inhibition of rat serum muramidase activity in vivo in relation to tissue changes

Chloroquine was tested for its inhibitory effect in vivo on the activities of rat serum and tissue muramidase. Daily administration of this anti-malarial drug to rats resulted in an appreciable reduction of kidney and liver enzyme activities 1 day after the first dose. No corresponding increases in enzyme activity were detected in the serum of treated animals up to day 9 when muramidase activity was then significantly reduced. Activity observed in the heart tissue was not affected until day 12, when the level was significantly reduced. These results suggest that chronic chloroquine administration to rats may result in an extensive inhibition of muramidase activity probably at the cellular/molecular level.