Structure and binding properties of serum albumin in uremic patients at different periods of hemodialysis.

Few diagnostic methods are available that describe uremia related changes of the albumin molecule structure in hemodialysis patients. The impaired human serum albumin (HSA) function is an essential part of the uremic syndrome and probably influences the long-term outcome of patients on maintenance dialysis. The albumin binding capacity (characterized for different binding centers on the molecule) is one of the relevant clinical parameters. During the current study, marker substances were utilized to evaluate center-specific binding capacity. Patients were divided into 3 groups depending on the time on hemodialysis (HD) treatment (in years) with healthy blood donors as control. Compared to healthy persons, results demonstrate a considerable impairment of binding characteristics in HD patients. Only in patients on maintenance HD for more than 5 years did ligand binding properties improve significantly. A correlation between the time of chronic HD and the recovery in binding capacity was found for the majority of binding centers of the HSA molecule. Similar results were seen applying such analytical methods as thermography (melting points) and thermofluorescence. Binding capacity impairment found for specified binding centers on the HSA molecule as the main serum carrier protein may have a direct impact on different clinical situations and the HD long-term outcome.

Biophysical studies on the correction of uremic human serum albumin binding defects by in vitro charcoal adsorption treatment.

Spectrofluorimetry, flow microcalorimetry, and differential scanning microcalorimetry (DSMC) were used to study the conformation, binding function, and ligand loading of uremic albumin obtained from the blood plasma of 2 end-stage renal disease (ESRD) patients before and after charcoal plasma treatment at different pH values (3.0-9.0). The spectrofluorimetric patterns of conformational N-F transition at low pH (4.2-3.5) are practically identical for both samples of uremic human serum albumin (HSA) and control HSA from healthy donors. After the charcoal treatment at pH 3.0 and 4.0, the enthalpies of complexing on uremic HSA with bromsulfalein and sodium dodecylsulfate approach that of donor HSA. The binding affinity of uremic HSA for sodium octanoate, phenol red, and salicylic acid following low pH charcoal treatment even exceed those of donor HSA. At the same time the charcoal treatment of uremic plasma at neutral and alkaline pH does not notably improve the binding characteristics of isolated HSA. Adsorption at low pH values completely restores the tryptophan fluorescence spectrum position of uremic albumin and improves the thermodynamic characteristics of its melting process. Using DSMC data, it can nevertheless be concluded that some conformational changes or a certain amount of high-affinity bound endogenous ligands still remain after low pH uremic HSA purification. The latter conclusion requires additional improvements of adsorption treatment of uremic plasma.

"Results of large surface hemodialysis (LSH): a shorter and cheaper treatment".

A surface area of 5 m2, a QB of 500 ml/min and a QD of 1000 ml/min reduces the time of hemodialysis to just 6 hours per week. All the patients had been in a conventional dialysis program for at least 2 years. These patients have now been in LSH for a period of between 2 and 3 years. Most patients have no appreciable residual function, they follow a free diet, living a normal life, and weigh between 51 and 88 Kg, ranging in ages from between 26 and 69 years. We use this technique with 3 schedules: Schedule I) 2 hours/3 days/week; Schedule II) 3 hours/2 days/week; Schedule III) 6 hours/1 day/week. In the 3 schedules the clinical and biochemical results have been the same as with conventional dialysis. With this technique the patients have greater freedom and comfort because they avoid 312 hours per year connected to the artificial kidney. The patients in Schedule II also avoid 52 dialysis sessions and 104 trips to the dialysis center per year. And the patients in Schedule III also avoid 104 dialysis sessions and 208 trips to the center per year. Furthermore, the cost savings in Schedule II is $2,500 per year/patient and in Schedule III $8,500 per patient/year.

Large-surface hemodialysis.

A hemodialysis device with a surface of 5 m2, a blood flow (QB) of 500 ml/min, and a dialysate flow (QD) of 1,000 ml/min has enabled the authors to obtain in 6 h/week the same clearances for urea, creatinine, uric acid, phosphates, and vitamin B12 as has conventional hemodialysis (CH), which takes from 12 to 15 h/week. Twenty-five patients were hemodialyzed throughout 1 year with CH and another year with large-surface hemodialysis, 20 with a creatinine clearance (CCr) of 0.5 ml/min and 5 with a CCr between 0.5 and 4.5 ml/min. All followed a free diet and led a normal life. Hemodialysis time was 6 h/week, and the results obtained were equal to those of the previous year with a CH of 12 h/week. The use of a bicarbonate dialysate rich in glucose, with a relatively high level of potassium and sodium, can avoid the disequilibrium syndrome caused by quick hemodialysis and makes possible the removal of excess liquid in only 6 h/week, without disturbances for the patient.

Must patients over 65 be haemodialysed?

This manuscript consists of a study of the results of 26 end stage renal failure (ESRF) patients, who commenced regular haemodialysis treatment (RHDT) from the age of 65 onwards (65-85) and who have been undergoing this treatment for periods ranging from 7 years to 3 months. These results are to be compared with those obtained from another group of 26 patients whose age ranged between 40 and 55 and who were treated with the same policy. The following parameters are compared: mortality, morbidity, life-style, cardiovascular situation, hypotension in haemodialysis, vascular access, anaemia, osteoarticular and peripheral nervous disorders, hypertension. We have not found any significant differences between both groups, besides a higher morbidity for patients over 65. Therefore, we recommend the inclusion of the older patients into RHDT programmes.