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A reversed-phase high-performance liquid chromatographic method was developed for the analysis of hypoxanthine in cord plasma. Cord plasma was precipitated with ammonium sulphate and after centrifugation the supernatant was injected into the chromatographic system. Separation of hypoxanthine was optimal with phosphate buffer (20 mmol/l, pH 7.65-7.75) as the mobile phase. Limit of determination using 200μl of the sample was found to be 1 μmol/l with a coefficient of variation of <10%. The imprecision of this method at the 10 μmol/l level was about 2%. The method described in this report for determination of hypoxanthine in cord plasma would also be suitable for determination of hypoxanthine in other biological fluids in clinical investigations. We have also determined reference values for hypoxanthine in citrate-preserved cord plasma. Rigorous sampling conditions and sample handling are important to achieve accurate results.

The secretory protein extracellular-superoxide dismutase is the major superoxide dismutase (SOD) isoenzyme in the extracellular space. There is evidence to suggest that most extracellular-superoxide dismutase in the vascular system is bound to endothelial cell surfaces. Venous stasis and physical exercise is known to induce release of several endothelium-associated factors into the plasma. However, venous stasis and physical exercise were not found to induce any release of extracellular-superoxide dismutase into plasma. The plasma activity of the intracellular isoenzyme CuZn SOD was doubled by venous stasis.

A functional parameter of the radiorenogram, the uptake ratio, was compared with the bilateral renal clearance of inulin and PAH in a mixed surgical-urological material. For kidneys without signs of obstruction to the urine flow, a close correlation was observed over the whole range of kidney function, which indicated that the uptake ratio of the renogram measured the renal function quantitatively with reasonable accuracy. For kidneys with signs of urinary obstruction the corresponding correlation was poor, probably owing to the inherent difficulties in correct sampling of the urine from a dilated renal pelvis. This made the values obtained from the bilateral clearance very unreliable in these patients.

Human liver slices were incubated with labelled glycerol and the incorporation of label into triglycerides and different phosphoglycerides was determined. Replacement of palmitic acid by linoleic acid in the incubation medium resulted in a decrease of the glycerol incorporation rate into phosphoglycerides. In response to addition of bile acids or choline to the incubation medium, a change in the distribution of incorporated glycerol among the different phosphoglyceride classes was observed. The incorporation rate into ethanol amine-phosphoglyceride was decreased and into choline phosphoglyceride increased. This finding indicates that bile acids exert a direct effect on the synthesis of phosphoglycerides in the liver.

AbstractHuman liver slices were incubated with glycerol-1,3-14C or fructose-U-14C. 50 of the label was recovered as glucose and 10 was incorporated into CO2and into lipids, respectively. At high fatty acid concentration in the medium the incorporation into CO2and glucose was suppressed, into triglycerides increased, and into phospholipids unchanged. The incorporation of fructose was suppressed with glycerol in the medium. The mean synthesis rate for phospholipids was 0.14 ± 0.01 μmoles/g liver per hour and for triglycerides 0.34 ± 0.04 μmoles/g liver per hour.

The composition of phospholipids in hepatic bile, gall bladder bile, and plasma from 18 patients operated on for acute cholecystitis was compared to the corresponding composition in 11 patients operated on for uncomplicated gall stone disease or peptic ulcer.In acute cholecystitis the relative and absolute concentration of lysolecithin was found to be decreased in plasma and increased in hepatic bile. The absolute as well as the relative concentration of all the phosphatides in the gall bladder bile varied widely in cases with acute cholecystitis, which probably reflects a variation in the resorption of the content of the diseased gall bladder. In cases with colourless bile in the gall bladder all the phosphatides occurred in very low concentrations. However, the relative concentration of lysolecithin in the 'cholecystic' gall bladders was found to be significantly increased and in three cases the absolute concentration of this phosphatide was found to be very high. The increased concentration of lysolecithin in bile from cases with acute cholecystitis may be caused by extrahepatic hydrolysis of lecithin, and evidence in favour of this interpretation is given.Whether the increased concentration of lysolecithin in bile is primary or secondary to the acute cholecystitis cannot be answered by the present investigation.

The normal serum monoamine (benzylamine and tyramine) oxidase (MAO) activity in 550 adults and 210 children was found to vary considerably with age and sex. In women using contraceptive steroids the serum MAO was significantly decreased. In 368 adults and children with diabetes mellitus the serum benzylamine oxidase level was increased. In 176 first degree relatives of persons with diabetes mellitus and in 73 persons with border line glucose tolerance tests the mean serum MAO activity was normal.