Biomedical subjects
Publications and source records attributed to Z Twardowski.
The concentrations of insulin (IRI), parathormone (PTH), calcitonin (CT), some electrolytes (Ca, Mg, P), vitamin D and glucose were determined in 6 patients with terminal renal insufficiency treated by CAPD.
The contribution of peritoneal cavity lymphatic absorption to ultrafiltration kinetics and solute clearances in continuous ambulatory peritoneal dialysis was evaluated in patients with normal (group 1) and high (group 2) peritoneal permeability X area during 4-h exchanges using 2 liters 2.5% dextrose dialysis solution with 30 g added albumin. Cumulative lymphatic drainage in all continuous ambulatory peritoneal dialysis (CAPD) patients averaged 358 +/- 47 ml per 4-h exchange and reduced cumulative net transcapillary ultrafiltration at the end of the exchange by 58 +/- 7.2%. The peak ultrafiltration volume was observed before osmotic equilibrium between serum and dialysate was reached and occurred when the net transcapillary ultrafiltration rate had decreased to equal the lymphatic absorption rate. Thereafter the lymphatic absorption rate exceeded the net transcapillary ultrafiltration rate, and intraperitoneal volume decreased. Extrapolated to 4 X 2 liters, 2.5% dextrose, 6-h exchanges per d, lymphatic drainage reduced potential daily net ultrafiltration by 83.2 +/- 10.2%, daily urea clearance by 16.9 +/- 1.9%, and daily creatinine clearance by 16.5 +/- 1.9%. Although lymphatic absorption did not differ between the two groups, lymphatic drainage caused a proportionately greater reduction in net ultrafiltration in group 2 (P less than 0.025), because these patients had more rapid dialysate glucose absorption (P less than 0.05) and less cumulative transcapillary ultrafiltration (P less than 0.01). These findings indicate that cumulative lymphatic drainage significantly reduces net ultrafiltration and solute clearances in CAPD and that ultrafiltration failure in CAPD occurs when daily lymphatic absorption equals or exceeds daily transcapillary ultrafiltration. Reduction of lymphatic absorption may provide a means for future improvement in the efficiency of CAPD.
The efficacy of calcium carbonate (CaCO3) as a phosphate binder has been limited by its tendency to cause hypercalcemia. Since standard dialysate calcium concentrations (3.0-3.5 mEq/l) increase the risk of developing hypercalcemia with large doses of CaCO3 by inducing positive calcium balance during hemodialysis (HD), we compared control of hyperphosphatemia in 41 HD patients during 4 months each of aluminum hydroxide (Al(OH)3) and CaCO3 when the dialysate calcium concentration was lowered, as required, to maintain the predialysis serum calcium concentration within the normal range. Mean predialysis serum phosphorus and calcium concentrations were 5.0 +/- 0.2 mg/dl and 9.3 +/- 0.1 mg/dl, respectively, during 4 months CaCO3 (9.2 +/- 0.3 g/day) and 4.9 +/- 0.2 g/dl and 9.1 +/- 0.1 mg/dl during the previous 4 months Al(OH)3 therapy (2.9 +/- 0.2 g/day). Reducing the dialysate calcium concentration to below 3.0 mEq/l (mean 2.1 +/- 0.04) in the 11 patients who developed hypercalcemia on CaCO3 decreased serum calcium (-1.1 +/- 0.15 mg/dl) and ionized calcium (-0.3 +/- 0.04 mEq/l) during HD, enabled CaCO3 (8.8 +/- 0.4 g/day) to be continued, and maintained predialysis serum calcium and phosphorus at 10.4 +/- 0.1 mg/dl and 5.2 +/- 0.3 mg/dl, respectively. No improvement in acidosis or biochemical hyperparathyroidism was observed during CaCO3 therapy but serum aluminum was significantly decreased after CaCO3 (p less than 0.005). We conclude that CaCO3 prevents interdialytic hyperphosphatemia as effectively as Al(OH)3 without increasing the predialysis serum calcium x phosphorus product, provided serum calcium is maintained within the normal range by adjusting the dialysate calcium concentration.
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Experiences with peritonitis in a continuous ambulatory peritoneal dialysis (CAPD) program at a single center over 8 years were reviewed. Home-acquired peritonitis rates have been less than 1 episode per patient year since 1982. Gram-positive organisms continue to account for most episodes in a similar proportion. Actual known contamination could be pinpointed in only 7.4% of cases, but was strongly suspected in 35.8% of episodes. Exit site and/or tunnel infections were thought to have caused 20% of the cases. Intrinsic peritonitis probably accounted for 10.5%. Recurrence of peritonitis with the same organisms following cessation of antibiotics represented only 2.1% of cases.
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In 20 patients under regular dialysis with an arteriovenous fistula in one forearm, platelet counts were measured in blood taken simultaneously from the cubital vein, the arterialized vein near the site of anastomosis, the femoral vein, and the femoral artery. Samples of blood from the fistula and from the cubital vein of the opposite limb were taken with and without stasis. The highest values were found in blood taken from the cubital vein without stasis. Platelet counts were identical in femoral artery and vein, but were 4.8 and 4.9%, respectively, lower than the cubital vein values. Platelet counts from fistula blood taken without stasis were 13.7% lower than in the cubital vein. Platelet counts were lower when samples of blood were taken with stasis: 11.2% in the cubital vein, 7.4% in fistula blood. The awareness of these differences is of practical importance for platelet behavior studies.
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Fourteen patients who had no signs of peritonitis were studied during CAPD. Different exchange time schedules were used alternating exchanges with 1.5% and 2.6% glucose solutions. Usually longer exchanges followed shorter ones and vice versa. Total exchange time varied from 2--10 hours. Maximal ultrafiltration volumes were observed after 3 hours with 1.5% and 5 hours wit 2.6% glucose solutions. For small molecular weight solutes (urea, creatinine, sodium, potassium, and phosphate) dialyzate to plasma concentration ratios tended to be lower with 2.6% glucose solutions during the shorter exchanges. Equilibrium between plasma and dialyzate was attained for all these solutes by 10 hours total exchange time. The concentration ratios for inulin were similar with both types of solution, and did not achieve equilibrium by 10 hours. Protein concentrations and losses were higher with 2.6% glucose solution. Total protein and immunoglobulin losses per 24 hours were markedly lower than those reported for intermittent peritoneal dialysis. White blood cell counts increased slightly up to 5 hours and then remained constant up to 10 hours. Mononuclear cell counts were consistently higher than those of granulocytes. The efficiency of dialysis was not markedly influenced by uneven distribution of total exchange time. If 1.5% and 2.6% glucose solutions were used for particular time schedules, slightly higher dialysis efficiency could be obtained by using hyperosmolar solutions for the longer exchanges. Ultrafiltration volumes, protein and immunoglobulin losses, cell counts in dialyzate, and clearance of inulin varied among individual patients. Protein losses correlated positively with serum protein concentration and the body surface area of the patient. Clearances of insulin also correlated with body surface area but ultrafiltration volumes did not.
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