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Mouse kidney polyribosome structure during ischaemia-reperfusion injury
PROSTAGLANDIN MODULATION OF AMINOGLYCOSIDE INDUCED NEPHROTOXICITY RATS AFTER ACUTE BLEEDING
V. Kalaidjieva. *M.Galabova Dept. of Physiology, *Dept. of Pathology, Faculty Medicine, Thracian Universi&, Stara Zagora, Bulgaria
LIPID PEROXIDATION AND DEFORhlABlLlTY OF ERYTHROCYTES IN HEMODIALYZED PATIENTS
IN
of
We aimed this study in order to determine prostaglandin contribution in the progression of aminoglycoside renal impairment in rats after acute hypovolemic stimulus. To this end we used 56 male Wistar rats with gentamicin (GM) - induced acute renal failure (50mg/kg/l5 days i.p.) cyclooxygenase inhibitor treated or not with indomethacin (IM) (4mg/kg/5 days s.c.). Hypovolemic changes were produced in 22 of the animals by cutting the tips of their tails (2% b.w.) at the last day of GM administration. Proximal tubule damage was evaluated histopathologically by light and electron microscopy. Plasma protein, urea, creatinine, electrolytes and urine aminoacids and protein were measured as well. Increased plasma creatinine and urea concentration were found in IM treated normovolemic and hypovolemic rats with kidney injuries (with 43.5% and 38.4% - normovolemic rats; 57.5% and 45.3% - hypovolemic rats) compared to 176.5pmolil creatinine and 16.5mmol/l urea in GM rats alone) (p
005 MOUSE KIDNEY POLYRIBOSOME DURING ISCHAEMIA-REPERFUSION S. PlcStina and S. Gamulin Department of Pathophysrologv. Universrv of Zagreb, Croatia
GLUTATHIONE BIOSYNTHESIS M. E. Anderson Department of Microbiology and Molecular Cell Sciences, The University of Memphis, Memphis, TN 38152 USA
STRUCTLIRE INJURY
Medrcal
faculty.
Glutathione (GSH) has many important cellular functions. It is synthesized from glumate, cysteine and glycine by the consecutive actions of y-glutamylcysteine synthetase (GCS) and GSH synthetase (GS). GCS is a heterodimer of H (catalytic) and L (regulatory) subunits. Higher levels of the H subunit in cultured cells correlate with increased GSH levels and acquired resistance to anticancer drugs. Specific inhibitors of GCS give insight into GSH functions. GS is a homodimer. Rat kidney GS displays negative cooperativity for y-glutamyl substrates, i.e. the binding of the first y-glutamyl moiety decreases the affinity for the second. Site specific mutations in the enzyme, especially in a highly conserved domain, suggest that amino acids in this region are important for GS catalysis and kinetic properties.
Ribosome sedimentation pattern was analysed by centrihgatior of sucrose density gradient postmitochondrial supernatant prepared from mouse ischaemia with kidney undergone and ischaemia repehsion respectively. Ischaemia, provoked by clamping of renal artery for 5 minutes, induces polyribosome disaggregation with an increase of monomer ribosome fraction from 20%, as present in control animals, to 359/o. In the course of reperfusion further polyribosome breakdown has been found. After IO minutes of repe&sion proportion of monomer ribosomes increased to 5 I %. Normalisation of functional distribution of ribosomes appeared only after 24 hours of reperfusion. Pre-treatment winth elongation inhibitor cycloheximide prevented the effect of ischaemia. but had no significant influence on polyribosome breakdown during reperfusion what speaks in favour of different mechanism polyribosomal decav. After reperfusion we have found in kidney tissue considerably higher concentration of malonaldehyde. a product of lipid peroxidation. which indicates formation of free oxygen radicals that may have caused nonenzymatic breakage of mRNA with consecutive increase of monomer proportion. Xanthine oxidase inhibitor allopurinol could not prevent repertision injury in our model.
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V. Kalaidjieva. *M.Galabova Dept. of Physiology, *Dept. of Pathology, Faculty Medicine, Thracian Universi&, Stara Zagora, Bulgaria
LIPID PEROXIDATION AND DEFORhlABlLlTY OF ERYTHROCYTES IN HEMODIALYZED PATIENTS
IN
of
We aimed this study in order to determine prostaglandin contribution in the progression of aminoglycoside renal impairment in rats after acute hypovolemic stimulus. To this end we used 56 male Wistar rats with gentamicin (GM) - induced acute renal failure (50mg/kg/l5 days i.p.) cyclooxygenase inhibitor treated or not with indomethacin (IM) (4mg/kg/5 days s.c.). Hypovolemic changes were produced in 22 of the animals by cutting the tips of their tails (2% b.w.) at the last day of GM administration. Proximal tubule damage was evaluated histopathologically by light and electron microscopy. Plasma protein, urea, creatinine, electrolytes and urine aminoacids and protein were measured as well. Increased plasma creatinine and urea concentration were found in IM treated normovolemic and hypovolemic rats with kidney injuries (with 43.5% and 38.4% - normovolemic rats; 57.5% and 45.3% - hypovolemic rats) compared to 176.5pmolil creatinine and 16.5mmol/l urea in GM rats alone) (p
005 MOUSE KIDNEY POLYRIBOSOME DURING ISCHAEMIA-REPERFUSION S. PlcStina and S. Gamulin Department of Pathophysrologv. Universrv of Zagreb, Croatia
GLUTATHIONE BIOSYNTHESIS M. E. Anderson Department of Microbiology and Molecular Cell Sciences, The University of Memphis, Memphis, TN 38152 USA
STRUCTLIRE INJURY
Medrcal
faculty.
Glutathione (GSH) has many important cellular functions. It is synthesized from glumate, cysteine and glycine by the consecutive actions of y-glutamylcysteine synthetase (GCS) and GSH synthetase (GS). GCS is a heterodimer of H (catalytic) and L (regulatory) subunits. Higher levels of the H subunit in cultured cells correlate with increased GSH levels and acquired resistance to anticancer drugs. Specific inhibitors of GCS give insight into GSH functions. GS is a homodimer. Rat kidney GS displays negative cooperativity for y-glutamyl substrates, i.e. the binding of the first y-glutamyl moiety decreases the affinity for the second. Site specific mutations in the enzyme, especially in a highly conserved domain, suggest that amino acids in this region are important for GS catalysis and kinetic properties.
Ribosome sedimentation pattern was analysed by centrihgatior of sucrose density gradient postmitochondrial supernatant prepared from mouse ischaemia with kidney undergone and ischaemia repehsion respectively. Ischaemia, provoked by clamping of renal artery for 5 minutes, induces polyribosome disaggregation with an increase of monomer ribosome fraction from 20%, as present in control animals, to 359/o. In the course of reperfusion further polyribosome breakdown has been found. After IO minutes of repe&sion proportion of monomer ribosomes increased to 5 I %. Normalisation of functional distribution of ribosomes appeared only after 24 hours of reperfusion. Pre-treatment winth elongation inhibitor cycloheximide prevented the effect of ischaemia. but had no significant influence on polyribosome breakdown during reperfusion what speaks in favour of different mechanism polyribosomal decav. After reperfusion we have found in kidney tissue considerably higher concentration of malonaldehyde. a product of lipid peroxidation. which indicates formation of free oxygen radicals that may have caused nonenzymatic breakage of mRNA with consecutive increase of monomer proportion. Xanthine oxidase inhibitor allopurinol could not prevent repertision injury in our model.
59