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A 38-year-old man suffering from chronic glomerulonephritis received a kidney from his HL—A identical sister. The HL—A identity was fully established by tissue typing with well-specified antisera and by mixed lymphocyte culture tests. One year after transplantation kidney function deteriorated, and repeated biopsies of the transplant, I131-Hippuran renography, and arteriography showed that the kidney was undergoing a chronic rejection. It is suggested that incompatibilities with regard to weak histocompatibility systems might have been responsible for the rejection of a human kidney.

Skeletal muscle adaptations to high intensity knee extensor strength and/or endurance training in patients with chronic heart failure were investigated. Eleven patients with chronic heart failure were randomized into two groups and exercised the m. quadriceps femoris 3 days/week for 8 weeks. After training, the maximal exercise intensity tolerated on the ergometer cycle was raised from 99 (32) to 114 (40) watts (W, P

Summary. The knee extensor and the whole-body exercise capacities were measured in 11 chronic heart failure (CHF) patients and 11 healthy age- and sex-matched controls, and were related to ejection fraction and to biochemical and histochemical markers of the musculature. The CHF patients had a 39% lower maximal oxygen uptake measured on an ergometer cycle than the healthy controls (1.54±0.57 vs. 2.51±0.70 1 min-1, P < 0.001). The low exercise capacity was markedly related to the ejection fraction (r =0.77, P < 0.001)TThe maximal strength of m. quadriceps femoris was 15% lower in the CHF patients than in the controls (P < 0.05). The cross-sectional area (CSA) of m. quadriceps femoris explained 55% (r =0.74, P < 0.001) of the difference in strength between both groups. The endurance capacity of m. quadriceps femoris was 30% lower in CHF patients than in controls, partly as a result of the 25% lower capillary density (P < 0.05) and the 27% lower aerobic enzyme capacity (P < 0.05), as estimated by the citrate synthase activity, in the CHF patients. The citrate synthase activity correlated with the maximal oxygen uptake (r =0.61, P < 0.05). Moreover, the ejection fraction, together with the CSA of m. quadriceps femoris, explained 75% (r =0.86, P < 0.01) of the difference in maximal oxygen uptake between CHF patients and controls. These results demonstrate that CHF patients have both a lower local and a lower whole-body work capacity than healthy controls. This is a function of a smaller leg muscle mass and a lower capillary density and mitochondrial enzyme capacity in the CHF patients; however, a lowered pump capacity of the heart is the factor which limits the exercise capacity the most.

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Eight healthy and regularly physically active men, 44-69 years old, performed one- and two-legged dynamic knee extension exercise at increasing work intensities, including one leading to exhaustion. Leg blood flow increased linearly in relation to work rate, reaching a peak value of 5.1 +/- 0.4 l min-1. With a mean weight of quadriceps femoris of 2.2 +/- 0.1 kg, a peak perfusion of 2.3 +/- 0.1 l kg-1 min-1 was attained. The maximal leg oxygen uptake was 0.72 +/- 0.07 l min-1 (0.33 +/- 0.03 l kg-1 min-1). At submaximal work the elevation in limb oxygen uptake accounted for between 70 and 100% of the rise in pulmonary oxygen uptake. Comparing two- with one-legged knee extension the cardiac output was 1.5 l min-1 higher at each work level, reaching 13.7 +/- 0.7 and 12.3 +/- 1.0, respectively at exhaustion, leaving 3.5 and 7.2 l min-1 of blood flow to the remaining body (cardiac output--leg blood flow). The mean arterial pressure was 119 +/- 5 mmHg at rest and increased to 155 mmHg for both test modes at the maximal work rate. The femoral arterial and venous plasma concentrations of lactate, ammonia and noradrenaline were significantly higher for two-legged as compared with one-legged exercise at the maximal load performed. However, the rate of release per leg, for both lactate and ammonia, did not differ between the two test conditions. It is concluded that physically active middle-aged men, with a well-retained muscle mass, can maintain a high skeletal muscle perfusion, similar to that of young males. However, the blood flow is achieved with a higher mean arterial pressure and an elevated sympathetic activity, as reflected by noradrenaline in plasma and spillover from the exercising limb.