Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Compared to prior studies which frequently pinpoint the impairment of one parameter or function, this paper reports for the first time an extensive characterization of the toxic effects of gentamicin in a single model of primary cultured rabbit proximal tubule cells developed without insulin and glucose. Biochemical, functional and morphological approaches were used. Cellular response pattern was examined after a 72-h exposure during either the exponential growth phase or the stationary confluency phase of the culture to 0.2, 1, and 2.5 mM gentamicin. The biochemical study after gentamicin exposure showed increased activities for N-acetyl-beta-D-glucosaminidase and alkaline phosphatase, decreased activities for sphingomyelinase, cathepsin B, Na+/K(+)-ATPase, lactate dehydrogenase and NADPH cytochrome C reductase. Functional evaluation revealed decreased protein synthesis and alpha-methylglucose transport after gentamicin exposure. Morphometric study made it possible to show that the density of lysosomes, the cell fractional volume of the lysosomal compartment, and the mean size of the lysosomal profiles are increased in the cells. Intracellular accumulation of gentamicin in proximal tubular cells was dose dependent and reached high levels in cultured cells. In conclusion, this model compared to others in the literature allowed us to demonstrate in vitro a close response pattern to the in vivo situation after gentamicin exposure.
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PMID:Characterization of gentamicin-induced dysfunctions in vitro: the use of optimized primary cultures of rabbit proximal tubule cells. 821 May 60

Toxic effects of gentamicin administration (10-80 mg/kg body weight, subcutaneously (s.c.), once daily for 7 days) on several enzyme activities of kidney and duodenal mucosa together with other parameters were compared between male rats and mice. In Wistar rat kidney, tubular brush border Mg(2+)-dependent, HCO3(-)-stimulated ATPase (Mg(2+)-HCO3(-)-ATPase) activity was inhibited by 40-80 mg/kg gentamicin in an almost dose-dependent manner with no changes in microsomal Mg(2+)-Na(+)-K(+)-ATPase activity. Cytosol carbonic anhydrase (CA) activity was inhibited only by 80 mg/kg gentamicin. In rat duodenal mucosa, Mg(2+)-HCO3(-)-ATPase and CA activities were unchanged by any dose of gentamicin. Rat serum urea nitrogen (UN), GOT and GPT concentrations and urinary N-acetyl-beta-D-glucosaminidase (NAG) activity were significantly increased by 80 mg/kg gentamicin. In ddY mice, however, almost all parameters described above were unaffected by gentamicin except for the urinary NAG activity which was increased only by 80 mg/kg gentamicin. The concentration of gentamicin in cytosol of rat whole kidney was approximately 3.4-fold higher compared with that in mouse kidney after 80 mg/kg treatment. In light microscopic analysis, 80 mg/kg gentamicin produced necrosis in the greater part of rat kidney proximal tubuli with no pathological findings in mouse kidney. In conclusion, Mg(2+)-HCO3(-)-ATPase activity in brush border membrane of rat proximal tubuli was selectively damaged in gentamicin nephrotoxicity, indicating that the rats are the suitable model for studies of gentamicin nephrotoxicity in humans.
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PMID:Comparison of gentamicin nephrotoxicity between rats and mice. 856 86

Spectrofluorimetric methods were used to investigate the effects of dexamethasone (dex) on cytosolic and lysosomal pH and on macrophage secretion of lysosomal contents. Secretion of N-acetyl-beta-D-glucosaminidase (NAG) in response to zymosan particles, lysosomotropic methylamine, or the H(+)-ATPase inhibitor bafilomycin A1 was inhibited by pretreatment with dex. The inhibition was not reversed by mannan and was seen also when secretion of preloaded fluorescein-labelled dextran was monitored, demonstrating that dex did not exert its effect by enhancing the reuptake of lysosomal enzyme. The binding of zymosan particles to macrophages was diminished after dex treatment, as was the zymosan-induced phospholipase C activation. However, the decreased binding of zymosan did not alone account for the inhibition of phospholipase C activation. Also, cytosolic pH was lowered by dex treatment. This might contribute to the inhibition of lysosomal secretion, but restoration of cytosolic pH by an increase in extracellular pH did not restore the secretory response. Lysosomal secretion induced by a combination of protein kinase C (PKC)-activating phorbol ester and methylamine was more resistant to dex than secretion induced by methylamine alone, or other secretagogues. We interpret this, together with previous data, to indicate that dex inhibits macrophage lysosomal secretion by attenuating one or more step(s) in a PKC-mediated signaling pathway necessary for the secretory response.
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PMID:Dexamethasone downregulates lysosomal secretion in mouse macrophages: involvement of signaling through protein kinase C. 911 39

Currently used fluorinated anesthetics are chemically related to methoxyflurane (MF), a drug that caused many cases of clinical acute renal failure during previous widespread use. To determine whether newer fluorinated anesthetics might also have nephrotoxic effects, three currently used agents (isoflurane (IF), sevoflurane (SF), and desflurane) or MF were added to rat proximal tubular segments, followed by assessments of cell integrity (ATP levels and percent lactic dehydrogenase release). Ether served as a negative control. MF, IF, and SF each induced lethal proximal tubular segment injury (up to 92, 71, and 30% lactic dehydrogenase release, respectively) and massive ATP depletion. ATP losses were observed at or near clinically relevant drug levels, they preceded lethal injury, and they correlated with approximately 50% and approximately 100% reductions in total and Na,K-ATPase-driven respiration, respectively. Clinically relevant inorganic fluoride levels simulated fluorinated anesthetic toxicity. However, fluoride release from the anesthetics (a cytochrome P450 process) did not appear to be required for toxicity (no protection with P450 inhibitors and no detectable inorganic fluoride release). As IF was judged to be one-third as toxic as MF, subclinical tubular injury (increased urine N-acetyl-beta-D-glucosaminidase (NAG) levels) after its use was sought in 19 surgical patients. Fifteen patients undergoing comparable operations with SF (approximately one-half as toxic as IF in vitro) and nine patients undergoing regional/ local anesthesia were controls. The IF group doubled its urinary NAG levels by the end of surgery (P < 0.005). Conversely, NAG levels remained stable in both control groups. The conclusions are that 1) currently used fluorinated anesthetics, particularly IF, share (but to a lesser degree) MFs tubulotoxic effects, 2) ATP depletion (probably due to decreased production) and Na,K-ATPase inhibition are likely contributing mechanisms, 3) fluoride is a prime determinant of this toxicity, and 4) tubular injury can be expressed at or near clinically relevant anesthetic/inorganic fluoride levels. That increased enzymuria can develop in patients after IF anesthesia suggests that the above in vitro data could have potential clinical relevance in selected patients.
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PMID:Spectrum and subcellular determinants of fluorinated anesthetic-mediated proximal tubular injury. 917 10

The influences of the calmodulin antagonist chlorpromazine (CPZ), and calcium channel blocker nimodipine (NIMO) and their combination on cadmium (Cd) poisoning of mice were studied. A series of biochemical parameters including urinary enzyme activities, blood and urine Cd levels, metallothionein (MT) contents in liver and kidney, hepatic ultrastructure and Ca(2+)-Mg2+ ATPase activity in erythrocyte membrane were determined. Animal models for Cd poisoning were established by peritoneal injection of 1/5 LD50 CdCl2. The experimental groups were protected by administration of CPZ, NIMO and CPZ and NIMO in combination 1 h before the injection of CdCl2. Five days later, samples were collected for analysis. The data showed that CPZ could protect kidney tissue against Cd-induced damage, as the urinary gamma-glutamyl-traspeptidase (gamma-GT) and N-acetyl-beta-D-glucosaminidase (NAG) activities were reduced significantly. There was neither evidence of the protective effect of NIMO on kidney tissue nor an indication of a synergistic effect of CPZ and NIMO. Both CPZ and NIMO showed a considerable protective effect against the decrease in Ca(2+)-Mg2+ ATPase activity, and a synergistic action was observed. Cd content in blood was reduced significantly by CPZ or the combination of CPZ and NIMO, but elevated by NIMO. Both CPZ and NIMO considerably increased MT contents in livers and kidneys and ameliorated damaged to the hepatic ultrastructures caused by Cd. The results indicated that these inhibitors could protect mice against the toxic effects of Cd in liver and kidney tissues, while CPZ was more efficient than NIMO. The combination of CPZ and NIMO exerted a synergistic action. The protective action of these two drugs might be relevant to the function of MT.
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PMID:Influences of chloropazine, nimodipine and their combination on the toxic effects of cadmium in liver and kidney of mice. 1067 85

Adriamycin, which is widely used in the treatment of various neoplastic conditions, exerts toxic effects in several organs. Adriamycin nephrotoxicity has been recently documented in a variety of animal species. The present study was designed to investigate the effect of lipoic acid on the nephrotoxic potential of adriamycin. The study was carried out with adult male albino rats of Wistar strain. Test animals were divided into four groups of six rats each as follows: Group I (control) received only normal saline throughout the course of the experiment. Group II (ADR) received intravenous injections of adriamycin through the tail vein (1 mg kg(-1) body wt day(-1)) once a week for a period of 12 weeks. Group III (LA) received lipoic acid (35 mg kg(-1) body wt day(-1)) intraperitoneally once a week for a period of 12 weeks. Group IV (ADR + LA) received a single injection of lipoic acid intraperitoneally 24 h prior to the administration of adriamycin through the tail vein once a week for a period of 12 weeks. Intravenous injections of adriamycin resulted in decreased activities of the glycolytic enzymes; hexokinase, phosphoglucoisomerase, aldolase and lactate dehydrogenase in the rat renal tissue. The gluconeogenic enzymes, glucose-6-phosphatase and fructose-1,6-diphosphatase, showed a decline in their activities on adriamycin administration. The transmembrane enzymes namely the Na+,K+-ATPase, Ca2+-ATPase, Mg2+-ATPase and the brush-border enzyme alkaline phosphatase also showed a decrease in their activities. This decrease in the activities of ATPases and alkaline phosphatase suggests basolateral and brush-border membrane damage. Decreased activities of the TCA cycle enzymes isocitrate dehydrogenase, succinate dehydrogenase and malate dehydrogenase, suggest a loss in mitochondrial function and integrity. Nephrotoxicity was evident from the increased excretions of N-acetyl-beta-D-glucosaminidase and gamma-glutamyl transferase in the urine of adriamycin administered rats. These biochemical disturbances were effectively counteracted on pre-treatment with lipoic acid, which brought about an increase in the activities of glycolytic enzymes, ATPases and the TCA cycle enzymes. On the other hand, the gluconeogenic enzymes showed a further decrease in their activities on lipoic acid pretreatment. LA pretreatment also restored the activities of the urinary enzymes to normal. These observations shed light on the nephroprotective action of lipoic acid rendered against experimental aminoglycoside toxicity.
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PMID:The influence of lipoic acid on adriamycin induced nephrotoxicity in rats. 1284 26

The present study was designed to evaluate the possible beneficial effect of lipoic acid in preventing the renal damage induced by cyclosporine A in rats. Male albino rats of Wistar strain were divided into four groups and treated as follows. Two groups received cyclosporine A by oral gavage (25 mg/kg/body weight) for 21 days to induce nephrotoxicity, one of which simultaneously received lipoic acid treatment (20 mg/kg body weight) for 21 days. A vehicle (olive oil) and a lipoic acid drug control were also included. Cyclosporine A induced renal damage was evident from the decreased activities of tissue marker enzymes (alkaline phosphatase, acid phosphatase, lactate dehydrogenase, aspartate transaminase and alanine transaminase) and decreased activities of ATPases (Na+, K+-ATPase, Ca2+-ATPase and Mg2+ ATPase). An apparent increase in the levels of serum constituents (urea, uric acid and creatinine) and urinary marker enzymes (N-acetyl-beta-D-glucosaminidase, beta-glucosidase, beta-galactosidase, cathepsin-D and gamma-glutamyl transpeptidase) along with significant decline in creatinine clearance were seen in the cyclosporine treated rats, which was reversed upon treatment with lipoic acid. Ultrastructural observations were also in agreement with the above abnormal changes. Lipoic acid effectively reverted these abnormal biochemical changes and minimized the morphological lesions in renal tissue. Hence, this study clearly exemplifies that lipoic acid might be an ideal choice against cyclosporine A induced cellular abnormalities.
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PMID:Therapeutic efficacy of DL-alpha-lipoic acid on cyclosporine A induced renal alterations. 1761 14

The potential protective effects of taurine and quercetin against gentamycin (GM)/diclofenac (DC) combined nephrotoxicity were investigated in rats. The results showed that administration of DC alone at an oral dose of 5 mg/kg b.wt/day for 28 days had no significant effect on the measured parameters, except for marked increase in urinary uronic acid excretion. Administration of GM alone at a dose of 100 mg/kg b.wt/day i.p. for 8 days resulted in obvious nephrotoxicity. Combined GM-DC treatment led to the most pronounced nephrotoxicity, as indicated by greater elevations in serum urea, creatinine and urinary N-acetyl-beta-D-glucosaminidase (NAG), together with severe depression of renal cortical Na , K+-ATPase, compared to GM-treated group. Moreover, only combined treatment resulted in significant decrease in urinary potassium and renal cortical glutathione peroxidase (GSHPx), together with an increase in renal cortical lipid peroxidation products (LPOs). Co-administration of taurine or quercetin normalized creatinine clearance and ameliorated the elevations in urinary proteins, uronic acids, NAG and renal cortical LPOs in GM/DC treated rats. The study justifies the use of taurine and quercetin as renoprotective agents against the nephrotoxicity caused by GM/DC therapy.
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PMID:Protective effect of taurine and quercetin against renal dysfunction associated with the combined use of gentamycin and diclofenac. 1906 45


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