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Summary. When data-points on the descending phase of autoendogenous plasma [75Se]selenomethionine-fibrinogen (75SeM-fibrinogen) radioactivity curves in rabbits were expressed as per cent of maximum radioactivity, they could be fitted to single exponential curves both in controls and in animals with enhanced fibrinogen synthesis from multiple causes. Intravascular half-disappearance times (HDTs) determined from these slopes were inversely related to maximum per cent incorporation of 75SeM into fibrinogen (r= 0.662, P

The rate of appearance of (14)CO(2) in expired air after the injection of a single dose of NaH(14)CO(3) has been determined in normal individuals both in the fasted and fed states. These data were combined with previously obtained results on the rate of disappearance of injected palmitate-(14)C from the bloodstream, to give a multicompartmental analysis of free fatty acid oxidation and esterification. The results confirm that glucose feeding promptly inhibits the rate of free fatty acid oxidation to CO(2). The "irreversible disposal rate," or irreversible flux of free fatty acids from the plasma, was also consistently reduced by glucose feeding. The diminution in irreversible disposal, not accounted for entirely by reduction of direct oxidation, must indicate suppression of other disposal mechanisms, including net esterification of free fatty acids. An average drop of 49% in "net esterification" when glucose was given may be compared with the 65% inhibition of rapid free fatty acid oxidation.

1. Methods are presented for the calculation of rates of synthesis or loss, mean transit time and total body pool of compounds from specific-radioactivity curves, without assuming a multicompartmental model and without fitting the data by exponential expressions. The methods apply to the steady state after either single injection or continuous infusion of a labelled compound. 2. The use of irreversible and reversible tracers and the effects of recycling of carbon on the estimations of the parameters of glucose metabolism are discussed. Methods for quantitatively determining recycling of glucose carbon by the use of glucose doubly labelled with 14C and 3H are presented.

Severe outbreaks of cutaneous leishmaniasis in Kabul led to complaints from the public. It was felt that a study of the epidemiology of the disease in this city would help not only in organizing better control measures in Kabul, but also in dealing with similar conditions that might arise elsewhere because of urbanization and migration from rural to urban areas. A housing project in north-west Kabul was studied through house-to-house visits of selected households. The prevalence of active sores was 11.6% and that of scars 4.3%, indicating both the recentness and the severity of the outbreak. All ages and both sexes were involved. The finding of infected dogs suggests that these animals may be reservoirs of infection. A survey of sandflies in the Kabul area showed the presence of 7 species of Phlebotomus, 4 of which are potential vectors, and 4 species of Sergentomyia.

The effect of a single glucose feeding upon the net inflow and outflow transport of plasma free fatty acids (FFA) has been studied in 75 unanesthetized rats. The animals were fasted for 22 +/- 2 hr; then 50 rats were refed 2 ml of 50% glucose by gastric intubation. At 0, 10-15, and 30-35 min after glucose refeeding, the rats were injected with palmitate-1-(14)C complexed to rat serum. The tracer dose included (131)I-labeled albumin. Plasma FFA concentration, (131)I concentration, and FFA-(14)C were measured at five time intervals after injection of the tracer dose. From these data the irreversible disposal rate, or net outflow transport, and the net inflow transport of plasma FFA were calculated. Estimations were based upon a special case of a general solution for measuring net inflow and outflow transport of a circulating metabolite. The general solution is independent of the number of compartments, how they are interconnected, the number of nonradioactive inflows, and where the inflows enter the system. Net inflow = net outflow transport = 7.6 micro eq/min in the fasted state and 3.5 micro eq/min in the new steady state that is reached 30-40 min after glucose refeeding. A very slight imbalance between the rates of net inflow and outflow transport could account for the rapid fall in plasma FFA concentration that results from a single glucose feeding. Theoretical and practical problems associated with studying inflow and outflow transport by means of the technique using a single injection of racer are discussed.