the serum calcium was increased by the oral administration of calcium carbonate, the decrement in serum i-PTH was only 25±6.65% when compared with 73.5±5.08% (P < 0.001) obtained by the administration of intravenous 1,25(OH)2D3. Thus, a similar serum calcium achieved by intravenous 1,25(OH)2D3 rather than calcium carbonate has a greater suppressive effect in the release of PTH.These studies indicate that 1,25(OH)2D3 administered intravenously rather than orally may result in a greater delivery of the vitamin D metabolite to peripheral target tissues other than the intestine and allow a greater expression of biological effects of 1,25(OH)2D3 in peripheral tissues. The use of intravenous 1,25(OH)2D3 thus provides a simple and extremely effective way to suppress secondary hyperparathyroidism in dialysis patients.

We studied angiographically the access route 1–27 months after the insertion of temporary dialysis catheters in 52 patients: 32 subclavian and 20 internal jugular. The two groups were statistically similar with respect to age, sex and race. The subclavian catheters were left in for a mean of 11.5 days (2–22) while the internal jugular ones were inserted for 15.8 days (5–25; p = 0.0015). One hundred percent of the internal jugular patients were free of any venogram abnormalities in their venous access return. In marked contrast, 50% of the subclavian sites had mild to severe strictures with 90% having 70–100% occlusion of the subclavian vein. Six patients had bilateral severe strictures. The long-term stricture rate of subclavian catheters in the subclavian vein was unacceptably high compared to the internal jugular route.

The effects of 9 +/- 6 months of exercise training on lipid and carbohydrate metabolism were studied in six hemodialysis patients. Training lowered triglyceride levels 39 +/- 25% (P less than 0.02) and increased plasma high-density lipoprotein cholesterol levels 23 +/- 22% (before, 26 +/- 5 mg/dl; after, 31 +/- 8 mg/dl; P less than 0.05). There was a 23% improvement in glucose tolerance (P less than 0.01) and a 40% reduction in hyperinsulinism (P less than 0.01) with no significant changes in body weight or diet. There was a 25 +/- 8% increase in hematocrits (before, 22 +/- 2%; after, 27 +/- 2%, P less than 0.01) and a 29 +/- 2% rise in hemoglobin concentrations (before, 7.0 +/- 0.8 g/dl; after, 9.0 +/- 0.6 g/dl, P less than 0.04) in five patients. In addition, during training antihypertensive medications could be reduced in three patients with maintenance of normal blood pressure. The improvements in lipid and carbohydrate metabolism diminished when two patients stopped training. These results suggest that physical training can improve some of the metabolic abnormalities observed in hemodialysis patients and could be important as a therapeutic modality.

This study examines the effects of 12 months of endurance exercise training (cycling, walking and jogging) on lipid profiles, glucose metabolism, blood pressure, anemia and psychological function in 14 hemodialysis patients. Maximal aerobic capacity (Vo₂max) increased 18% in the exercisers (p < 0.01), but did not change in 11 controls. This was associated with a reduction in depression, a decrease in dosages of antihypertensive medications, a significant increase in hematocrit and hemoglobin levels (red cell mass rose, plasma volume did not change), a decrease in plasma triglyceride by 23% (p < 0.05) and an increase in high-density lipoprotein cholesterol (HDL-C) levels by 21% (p < 0.01) (both HDL-C and triglyceride levels worsened in the sedentary controls), and an 18% increase in glucose disappearance rates (p < 0.05) in spite of a 52% decrease in fasting insulin levels (p < 0.01), suggesting that insulin sensitivity improved. These results demonstrate that some of the complications present in hemodialysis patients may be caused by their sedentary life-style, rather than endstage renal disease itself. This suggests that rehabilitation through exercise is possible for these patients. By reducing coronary risk factors in hemodialysis patients, exercise training may also decrease their heightened morbidity and mortality from atherosclerotic complications. These possibilities need to be examined in a longitudinal study.

Since platelet cyclo-oxygenase is much more sensitive to inactivation by aspirin than is the enzyme in the arterial wall and low doses of aspirin may prevent thrombosis by blocking thromboxane synthesis, we conducted a randomized, double-blind trial of aspirin (160 mg per day) vs. placebo in 44 patients on chronic hemodialysis. The study was continued until there were 24 patients with thrombi and both groups had been under observation for a mean of nearly five months. Thrombi occurred in 18 of 25 (72 per cent) of patients given placebo and 16 of 19 (32 per cent) of those given aspirin (P less than 0.01). The incidence of thrombosis was reduced from 0.46 thrombi per patient month in the placebo group to 0.16 thrombi per patient month in the aspirin group (p less than 0.005). A dose of 160 mg of aspirin per day is an effective, nontoxic antithrombotic regimen in patients on hemodialysis.