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Biomedical subjects

R Hansson

Publications and source records attributed to R Hansson.

At least 19 recordsLinked to original sources
PubMed1990

Renal function during reperfusion after warm ischaemia in rabbits: an experimental study on the possible protective effects of pretreatment with oxygen radical scavengers or lidoflazine.

Survival and renal function were studied after 60 min of renal ischaemia and contralateral nephrectomy in four groups of French loop rabbits. One group served as untreated control animals. The other groups were pretreated with superoxide dismutase (SOD) and catalase, lidoflazine or a buffered albumin solution containing mannitol, L-methionine and MgCl2. Six out of nine rabbits died during the 14-day follow-up period in the untreated control group, while the corresponding figure in each of the three treatment groups was one out of nine. Five of the rabbits that died exhibited azotaemia or hyperpotassaemia that could explain the death, while four died of non-renal related causes. In the surviving animals, no differences in serum creatinine, potassium and sodium concentration or urinary output of osmoles was observed between the four groups. The increase in serum creatinine of the French loop rabbits observed after 60 min of ischaemia was considerably less pronounced than the corresponding increase observed in New Zealand White rabbits, indicating that the kidneys of the former strain are more tolerant to ischaemia. A cardiomyodepressant factor could be demonstrated in the venous effluent from previously ischaemic kidneys. This release could not be prevented by pretreatment with SOD and catalase.

Animals↗
PubMed1988

Effects of oxygen free radical scavengers, xanthine oxidase inhibition and calcium entry-blockers on leakage of albumin after ischaemia. An experimental study in rabbit kidneys.

The effect of pretreatment with various substances protecting against oxygen free radicals on the leakage of proteins across the vessel walls of rabbit kidneys induced by ischaemia has been studied. The leakage of proteins was estimated from the difference between the 120-min distribution space of [131I]albumin and the 5-min distribution space of [125I]albumin, the latter mainly measuring the intravascular volume. Neither SOD (superoxide dismutase), catalase, allopurinol or two different Ca2+ channel blockers (nifedipine, felodipine) could alone reduce the leakage induced by ischaemia. A combined pretreatment with SOD, catalase and nifedipine reduced the leakage in the cortex, and pretreatment with mannitol alone reduced the leakage in the cortex and outer stripe of the medulla. The results indicate that oxygen free radicals are involved in the leakage of proteins across the vessel walls induced by ischaemia, but that other mechanisms are involved as well.

Allopurinol↗
PubMed1987

Effects of ischaemia on leakage of albumin in rabbit kidneys.

The effect of ischaemia on the leakage of proteins across the vessel walls in rabbit kidneys was studied. The leakage of proteins was estimated from the distribution space of labelled albumin. Various methods to calculate the vascular volume yielding the true extravascular leakage were tested. The most reliable method appeared to be to use the same tracer (131I-albumin, 125I-albumin) for both estimating the leakage and the intravascular volume. One hour of ischaemia induced a drastic increase in the extravasation of proteins in the cortex and outer zone of the medulla but not in the inner zone.

Animals↗
PubMed1986

Kidney protection by pretreatment with free radical scavengers and allopurinol: renal function at recirculation after warm ischaemia in rabbits.

Renal function and morphology were studied before and after 60 min of renal ischaemia and contralateral nephrectomy in five groups of rabbits. The animals were pretreated with superoxide dismutase, catalase, allopurinol or mannitol. One group was not pretreated and served as a control. A moderate transient increase in serum creatinine concentration was observed in the control rabbits, while a significantly less pronounced increase was noted after pretreatment with superoxide dismutase, catalase and mannitol. Pretreatment with allopurinol did not significantly reduce the postoperative increase in serum creatinine and sodium excretion, but the urine osmolality returned to normal more rapidly than in the control group. The appearance under the light microscope of kidney tissue taken from surviving rabbits was found to be normal irrespective of pretreatment. Severe tubular necrosis was observed in the kidneys from rabbits that died during the observation period.

Allopurinol↗
PubMed1986

Effect of oxygen free radicals on rabbit and human erythrocytes. Studies on cellular deformability.

Changes in deformability of rabbit and human erythrocytes caused by exposure in vitro to the oxygen free radical generator hypoxanthine and xanthine oxidase were studied. The deformability reduction observed after 30 min of exposure to hypoxanthine-xanthine oxidase could be prevented by pretreatment with SOD, while after only 5 min of such exposure allopurinol and catalase also appeared to have a protective effect. Exposure of human erythrocytes to hypoxanthine and xanthine oxidase in Krebs solution prevented an otherwise occurring hemolysis. Exposure to both substances or to xanthine oxidase alone in Dulbeccos phosphate solution produced a reduction in deformability. The results indicate that exposure of erythrocytes to free oxygen radicals reduces deformability and that this effect may contribute to the myocardial dysfunction and the epicardial erythrostasis observed during open-heart surgery.

Adult↗
PubMed1977

Isolation and identification of a trypsin-resistant fragment of human serum albumin with bilirubin- and drug-binding properties.

Extensive digestion of human serum albumin with trypsin at pH 8.8 yields essentially one main fragment which is resistant to further tryptic degradation. The fragment has been characterized by amino acid analysis, N- and C-terminal analyses, cyanogen bromide digestion, electrophoresis, ultracentrifugation and gelfiltration, and circular dichroism measurements. The results indicate that the main fragment consists of the amino acids 182-585. Repeated digestion did not degrade the isolated fragment further. The fragment mainly retains the secondary and tertiary structure of intact human serum albumin as well as its capacity to bind bilirubin and diazepam. The localization of the binding sites for these substances is discussed.

Amino Acids↗