1. Leg blood flow, uptake of oxygen and glucose and release of lactate by the leg and changes in intramuscular concentrations of metabolites were studied at rest and during exercise of increasing work loads in thirteen patients with occlusive disease of the iliac or superficial femoral arteries. 2. Leg blood flow (dye-dilution technique) and oxygen uptake during exercise were low and levelled with increasing work load. Considerable increases were noted in muscle lactate concentration and in the net release of lactate from the exercising leg. Muscle content (needle-biopsy technique) of ATP and creatine phosphate decreased during exercise, with an almost complete depletion of creatine phosphate in three patients. The decrease in muscle glycogen during work did not differ significantly from that of control subjects. 3. Repeated exercise after reconstructive surgery showed a considerable improvement in physical working capacity. Leg blood flow and oxygen uptake during exercise were significantly higher than before surgery and increased linearly in relation to work intensity. The decrease in creatine phosphate and lactate concentration of the thigh muscle during exercise was less pronounced and the release of lactate was lower than before vascular reconstruction. 4. It is suggested that the onset of the severe muscle symptoms during exercise in patients with occlusive arterial disease of the leg may be related to a low concentration of ATP and creatine phosphate in the affected muscles.

The capacity of human skeletal muscle and kidney homogenates to synthetize prostaglandins (PGs) from exogenous precursor was investigated. Low-speed supernatants of muscle as well as renal medullary and cortical homogenates were incubated with 14C-labelled arachidonic acid (14C-AA) prepared as a sodium salt. 14C-PGs in the incubates were extracted, separated with thin-layer chromatography (TLC) and quantified by radioscanning. In the skeletal muscle incubates 14C-AA was converted into 14C-PGs with a time-dependent yield, most effectively after 10--15 min incubation. Well-defined radiopeaks parallel to unlabelled standards of PGD2, PGE2, PGF2 alpha and 6-keto-PGF1 alpha were obtained in the chromatograms. PGE2 was the main PG formed, constituting over 50% of 14C-activity, whereas 6-keto-PGF1 alpha, PGD2 and PGF2 alpha were found in considerably lower proportions. In the renal medullary incubates, PGE2 likewise accounted for the largest part of 14C-PGs formed, but significant relative amounts of PGF2 alpha and PGD2 were also found. A minor peak, corresponding to 6-keto-PGF1 alpha and thus indicating formation of PGI2, was also obtained. In contrast to the medulla, no 14C-PGs could be found in the renal cortical incubates. The results demonstrate the existence of a considerable tissue specificity in the quantitative and qualitative expression of PG biosynthesis in man.

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The free fatty acid (FFA) uptake and oxidation and the carbohydrate substrate exchange of Wg muscles were studied during exercise in 14 patients with occlusive disease of the iliac or femoral arteries before and 3-6 mnonths after reconstructive vascular surgery and in 5 healthy subjects. '4C-labeled oleic acid was infused continuously at rest and during exercise at work loads of 150-400 kg-m/min. The arterial concentration of FFA was similar both at rest and during exercise in patients and controls. The patients showed a smaller increase in the fractional turnover of FFA during exercise. Leg uptake and release of FFA in terms of micromoles per liter plasma did not differ significantly either at rest or during exercise between patients and controls. FFA oxidation could not be measured at rest but exercise data showed a lower fractional oxidation of FFA (P < 0.001) in the patient group (53±6%) compared with the controls (84±2%). For the entire material, fractional oxidation of FFA showed a significant negative regression on the lactate/pyruvate ratio in femoral venous blood. The ventilatory respiratory quotient (RQ) and the leg muscle exchange of glucose and lactate in the patients exceeded that of the controls. When six patients were studied after reconstructive surgery, fractional oxidation of FFA had risen from a preoperative value of 47±8 to 90±10%, other data for leg muscle FFA metabolism being unchanged.It is concluded: (a) that substrate catabolism by the leg muscles during exercise in these patients proceeds A preliminary report on some of the results was presented at the Karolinska Institute Symposium on "Muscle Metabolism during Exercise" held in Stockholm, Sweden, 6 September 1970 (1).

Oxygen uptake, cardiac output, stroke volume and arterial and central blood pressures were measured before and after induction of neuroleptanaesthesia in 27 subjects. Nine were elderly patients operated on for obliterative arteriosclerotic disease, and the other 18--nine elderly and nine younger patients--underwent operation for varicose veins. Cardiac output, stroke volume and systolic arterial blood pressure decreased significantly with a corresponding decrease in oxygen uptake. The changes were most pronounced in the patients with arteriosclerotic disease. The arterio-venous oxygen difference was unchanged in the arteriosclerotics and decreased in the other two groups. The central pressures remained unchanged in all groups. It is concluded that the cardiovascular changes induced by neuroleptanaesthesia are due to a decrease in oxygen uptake and not to myocardial depression.