Search

Background: Lipid components are considered to play an important role in ischaemia reperfusion injury although the mechanism of their action remains unknown. Accumulation of lipid metabolites in ischaemic tissues is a consistent observation, but exactly how these lipids are cleared from the tissues by the circulating blood during reperfusion is still open to speculation. In the present study, levels of blood lipids (fatty acids, phospholipids, triglycerides, cholesterol, lysolecithin and lysolecithin platelet activating factor (lyso PAF)) and the enzyme phospholipase A2 were determined in an experimental animal model (dogs) of ischaemic reperfusion injury., Methods: The injury was induced by 4 h of aortic clamping followed by 2 h of reperfusion (unclamping). Blood samples were collected before clamping and at predetermined time intervals (0, 15, 60 and 120 min) after the release of clamp. The lipid contents were analysed and compared with sham-treated control dogs., Results: The results showed significantly elevated levels of triglycerides and phospholipase A2, during ischaemia and reperfusion in experimental animals indicating tissue damage in the ischaemic phase continuing into the reperfusion phase and the risk of systemic damage from these toxic substances. Total fatty acid content in the circulating blood showed decreasing trends during the same time interval, which suggested possible reduced clearance of accumulated fatty acids from the affected tissues. Serum cholesterol, phospholipids, lyso PAF and lysolecithin did not show any significant variation compared with control dogs., Conclusions: It is possible that the delayed clearance of fatty acids may be due to the presence of fatty acids binding proteins in the ischaemic tissue, which trap these fatty acids in the tissues during ischaemic reperfusion injury. The prolonged retention of the accumulated fatty acids in the tissues in association with elevated triglycerides and phospholipase A2 activity may contribute to ischaemia reperfusion injury.

Urinary citrate excretion was estimated colorimetrically from urine samples collected every 3 h for 24 h from 25 healthy adult males (non-stone formers; mean age 39 +/- 7 years) and 25 male patients suffering from calcium nephrolithiasis (stone formers; mean age 41 +/- 6 years). The 24 h citrate excretion was 2.47 +/- 0.65 mmol in non-stone formers and 2.02 +/- 0.71 mmol in stone formers. This difference was not significant. However, cosinor rhythmometry revealed a significant circadian rhythmicity in urinary citrate excretion in the healthy males which was absent in the stone formers; the amplitude was 0.06 mmol in non-stone formers and 0.017 mmol in stone formers. The acrophase was located at 14:25 h in non-stone formers and at 23:30 h in stone formers.

Biochemical, histochemical and histological studies of the effects of an oily extractive from the seeds of Celastrus paniculatus were done on the testes and liver of adult rats. The testis of treated animals showed vacuolization, germ cell depletion and arrest of spermatogenesis. The livers revealed focal necrosis in animals receiving 0.2 ml i.p. every other day for 30 days, but 45 days post treatment these lesions were absent. Intermediate repair and regenerative changes were apparent 30 days post treatment. These results indicate that Celastrus paniculatus oil may have useful antifertility effects and that the degenerative changes seen in the liver are reversible with time.

Circadian rhythmicity in urinary volume and excretion of creatinine, calcium, oxalate, uric acid and phosphate was studied in 15 idiopathic stone formers and in 17 control subjects who were age-matched, related adult males, living in the same house and engaged in similar occupations to those of the stone patients, but who had no clinically obvious stone disease. Three-hourly urine samples were collected and creatinine, calcium, oxalate, uric acid and inorganic phosphate were estimated. The time series of data were analysed by cosinor rhythmometry. Circadian rhythmicity has been described in urinary volume and urinary excretion of creatinine, calcium, oxalate, uric acid and inorganic phosphate in normal subjects, but it was not detected in the stone formers. The control subjects exhibited a circadian rhythmicity only in urinary volume and creatinine excretion. Thus they occupied a position midway between healthy adults, who exhibit circadian rhythmicity in all of the above parameters, and the stone formers, who appear to have lost it altogether.