Influence of continuous ambulatory peritoneal dialysis on some plasma and erythrocyte vitamins--retrospective study.

This paper reports a retrospective study on the clinical and laboratory analysis of some serum and erythrocyte vitamins in our chronic renal failure patients who were treated with Continuous ambulatory peritoneal dialysis (CAPD). In the first patient and in the next 10 patients the CAPD treatment began (in years 1980-1984) at the Internal Department-Strahov of General Faculty Hospital in Prague and after 2 or 3 weeks they continued in CAPD programme at the Dialysis Centre of IVth Internal Clinic, Faculty Hospital in Kosice. In the third group of CAPD patients (among them 8 patients were treated in Prague and 5 patients in Kosice) all biochemical parameters including vitamins were determined at Nephrological laboratory of the IVth Internal Clinic in Kosice. Besides that the aim of this paper was to show the above standard relationship and a long-term cooperation between above mentioned departments, and to contribute to Czech and Slovak reciprocity and to the history of clinical nephrology. The paper was presented on the important occasion of the 30th anniversary of the first continuous ambulatory peritoneal dialysis, which was performed at Internal Department-Strahov, Prague in the year 1978.

[Results of proteomic-based study of the kidney, urine, plasma, and uremic ultrafiltrate. Potential applications of the results in nephrology]. / Výsledky proteomického vysetrení ledvin, moce, plazmy a uremického ultrafiltrátu. Jejich potenciál pro nefrologii.

Proteomics, a new branch of science studying proteins, only emerged in the postgenomic period. What makes so it important is that fact even the exciting recent insights into the genome have not furnished sufficient information about proteins, which are the main agents behind cellular, subcellular, and supracellular functions. The center of attention of proteomics is identification of proteins in complex protein mixtures with an emphasis on the identification of a large number of proteins at a time, search for interrelations between identified proteins, their more exact characterization, determination of quantity, and better understanding of their function. Proteomics in nephrology is still in its infancy. Although it makes use, like in other fields, of various methodological procedures, the principal techniques are two-dimensional gel electrophoresis and MALDI-TOF (matrix-assisted laser desorption/ionization-time of flight) mass spectrometry. Nephrology-related proteomic findings made to date inform about normal protein composition of renal parenchyma, urine and plasma, and on their alterations under the influence of physiological or pathological stimuli. Search is under way for uremic toxins in uremic infiltrate, and their elimination from the body of patients with renal failure using various dialysis membranes is being investigated. Findings have made it possible to formulate hypotheses regarding renal physiology and pathology. Current nephrology-related proteomics raises more questions than it answers. Its potential for improving the understanding of physiological processes, pathological states, non-invasive diagnosis, monitoring of therapy, development of drugs and therapeutic procedures is a major promise for future.

[The first conferences of dialysis nurses and staff in Czechoslovakia]. / Z pocátku konferencí dialyzacních sester a pracovníku v Ceskoslovensku.

After successful seminars of dialysis nurses from the Clinic of Internal Medicine in Plzen in 1974, 1975 and 1976 the Board of the Czechoslovak Society of Nephrology entrusted the Dialysis Centre from the Clinic to organise national conferences for dialysis staff. The first conference of dialysis staff took place in 1978 in the hotel Solidarita at Spicák. Following conferences were taking place in the manor Zinkovy near Plzen till 1989. To establish independent dialysis conferences was necessary because of a rich content of those conferences and an effort not to limit traditional nephrology at nephrology congresses. The conferences always took from 2 to 3 days and dialysis physicians, technicians and nurses participated in. Since 1981 selected professionals from abroad took part in them too. Participants of the conferences and members of the Czech Society of Nephrology who always had their meetings during the conferences think that nephrology conferences contributed to progress in dialysis and transplantation area in our country. Dialysis nurses in Plzen made a special contribution to organization of conferences which lead to giving those conferences a nickname the Conferences of Dialysis Nurses. Since 1980 the national conferences in Zinkovice alternated with national conferences in Eastern Slovakia lead by professor Mydlík. There were no other conferences of dialysis staff organised in the Czechoslovakia within years 1978-1989.

[Hemodialysis in the treatment of chronic kidney failure. Present status]. / Hemodialýza v lécbe chronického selhání ledvin. Soucasný stav.

In advanced countries haemodialysis treatment is available to all patients with chronic renal failure who need it. At present nephrologists must resolve the problem when it is possible to with-hold long-term haemodialysis treatment, or withdraw it because it no longer leads to prolongation of a good quality life. The results of long-term dialysis treatment depend on the correct timing of its initiation and the quality of nephrological care provided already a long time before the development of renal failure. The morbidity, mortality and quality of life of the patients are influenced in a fundamental way by the quality of provided haemodialysis. An important factor is the dose of dialysis treatment evaluated according to index Kt/Vurea reflecting the urea elimination and obviously also the elimination of other low molecular weight substances. Although prospective controlled trials did not prove so far a favourable effect of haemodialysis membranes permeable for larger molecules ("high-flux" membranes) on the patients' fate, the possible toxic effect of so-called middle molecule substances and peptides with a low molecular weight is assumed. Data suggesting improvement of the quality of life of patients having daily haemodialyses call for further investigations. A still unresolved problem of contemporary haemodialysis systems remains inadequate biocompatibility which leads to reactions associated with possible acute and long-term damage of dialyzed patients.

[Acute adverse effects of dialysis]. / Nezádoucí reakce na dialyzátory s akutním prubehem.

Adverse reactions to dialyzers are a not very frequent, but because of the serious, sometimes fatal course, a dreaded complication of haemodialysis treatment. Most important among these reactions are hypersensitive reactions (anaphylactoid, reaction type A to dialyzer), which develop as a rule within the 10th minute of the procedure, and the reaction caused by the action of perfluorohydrocarbon which develop hours after onset or even completion of haemodialysis. Explanation of the development of hypersensitive reactions (HSR) by complement activation and formation of anaphylatoxins C3a and C5a during contact of blood with the bioincompatible dialysis membrane has been abandoned. Evidence of the etiological role of ethylene oxide (ETO) in the development of HSR influenced the selection of materials for the production of dialyzers and sterilization during manufacture, it emphasized the importance of rinsing of the dialyzer in the dialysis centre and led to the wide application of alternative methods of sterilization by gamma radiation and steam. HSR may be also caused by overproduction of bradykinin and inhibition of its degradation or degradation of its metabolites. Excessive bradykinin production caused by dialysis membranes with a negative charge is potentiated e.g. by a lower pH and increased plasma dilution in the initial stage of haemodialysis. Inhibition of bradykinin degradation develops during treatment with angiotensin converting enzyme inhibitors (ACEI). In prevention of HSR associated with bradykinin in addition to elimination of a combination of a negatively charged dialysis membrane and ACEI treatment a part is played also by rinsing of the dialyzer before haemodialysis with a bicarbonate solution and the modification of the membrane surface (implemented by the manufacturer) which reduces its negative charge. The first reaction to the dialyzer in conjunction with perfluorohydrocarbon (PF-5070), used in production of some dialyzers for testing the integrity of their capillaries were first described in 2001 and have caused since then at least 50 deaths. Reactions associated with PF-5070 are still the subject of research and forensic investigations. Despite this they draw already now attention to the failure in manufacture of dialyzers, to the inadequacy of hitherto accepted testing procedures of dialyzers and the constant necessity of careful clinical, laboratory and post-mortem examination of dialyzed patients.

[Pure red cell aplasia in erythropoietin therapy in patients with kidney failure]. / Cistá aplazie cervené rady pri lécbe erytropoetinem u nemocných se selháním ledvin.

Since the nineties of the previous century, incidence of pure red-cell aplasia (PRCA) in patients with chronic renal failure (CRF) and renal anaemia treated with recombinant human erythropoietin (rHuEPO) has significantly increased. Due to the positive effects of rHuEPO on quality of life, lowering of morbidity and mortality of patients with CRF, such increased incidence has attained a widespread interest, though PRCA remains only a rare complication. The responsibility for the development of PRCA lies with the neutralizing anti-erythropoietin antibodies. The rise of antibodies and development of PRCA is related to the subcutaneous administration of erythropoietin and in the vast majority of patients to the treatment with Eprex, one of the epoetins alpha. At present, the most probable explanation is a change of the stabilizer in Eprex formulation, which is related to the increased immunogeneity of the product. The subcutaneous administration of rHuEPO, preferred for medical and economical reasons in both American and European guidelines, is known for its higher immunization power. Properties of the product, emphasized by the route of administration, can cause the rise of these antibodies. To prevent the rise of anti-erythropoietin antibodies and the development of PRCA, regulatory authorities and Eprex producers decided that Eprex cannot be administered to CRF patients subcutaneously, but only intravenously. Also the requirements on the handling of Eprex have become more stringent. Limitations do not concern either epoetin beta (NeoRecormon) or other epoetins alpha (of which the latter are not available in this country). Therapy of PRCA in patients treated with rHuEPO is based on suspension of rHuEPO and on the immunosuppressive therapy. Many questions concerning PRCA in CRF patients treated with rHuEPO remain unsolved. It is necessary to study further the ethiopathogenesis of this complication and possibly adjust preventive and therapeutic measures.

Fibrinolysis in chronic renal failure, dialysis and renal transplantation.

The best known function of the fibrinolytic system is its ability to dissolve blood clots. The key enzyme of fibrinolysis, plasmin, is formed by conversion from plasminogen through the action of activators, the most important of which is tissue type plasminogen activator (tPA). Low levels of tPA or excessive levels of plasminogen activator inhibitor-I (PAI-I) cause hypofibrinolysis, causally related to the development of atherosclerosis and associated thrombotic complications, as well as with the development of venous and arterial thrombosis. A chronic decrease in renal function leads to hypofibrinolysis due primarily to low levels of tPA. Hypofibrinolysis is present both in patients treated by long-term hemodialysis and by peritoneal dialysis. The hemodialysis procedure acutely raises the plasma levels of tPA, primarily as a result of the bioincompatibility of materials in the extracorporeal circuit. In peritoneal dialysis, dialysis solution dwell time is associated with an increase in PAI-I levels in the abdominal cavity. Fibrinolysis defects occur also in renal transplant recipients. In transplant patients, the main abnormality is also hypofibrinolysis which, however, unlike the situation with the other methods of renal replacement therapy, is secondary to a rise in PAI-I. A role in the increase of the plasma levels of PAI-I in transplant patients is played by steroid- and cyclosporine-based immunosuppression, most likely by metabolic disorders such as insulin resistance or dyslipoproteinemia, and by genetic factors. Animal experiments with chronic rejection have shown abnormalities in local fibrinolysis in the graft, particularly increased PAI-I expression. Fibrinolysis defects may contribute to an early and frequent development of atherosclerosis in patients with chronic renal failure, to chronic dysfunction of the renal transplant, or to peritoneal fibrosis and peritoneal catheter obstruction in patients on peritoneal dialysis. The exact role of hypofibrinolysis in the development of these complications, and the potential for modulating it, warrant further research.

[Transitional elements and free radicals]. / Prechodné prvky a volné radikály.

Iron and copper are essential trace elements, which in certain conditions, namely in the ionised form or in low-molecular complexes, can participate in single electron reactions and catalyse formation of free radicals, including the dangerous hydroxyl radical. Similar behavior have also some other transitive metals. Our overview is aimed on the role of transitive elements in the formation of free radicals and on the mechanisms that organisms have to prevent it. The highest attendance is given to the metabolism of iron and cooper. Consistent protection against free transitive metals (by binding with proteins, by oxidation or sequestration in a special compartment) enables organism to use their beneficial and required features without impairment of cell. Knowledge of these mechanisms provides the means to predict and effectively prevent the brake down of such defend systems in situations of the intravascular hemolysis, hemodialysis, administration of iron, impairments of the iron and copper metabolism, intoxication by oxidising substances etc.

The effect of heparin rinse on the biocompatibility of continuous veno-venous hemodiafiltration.

UNLABELLED: The aims of our cross-over randomized study were (1) to assess hemostasis in patients with acute renal failure (ARF) and (2) to determine whether or not the generally recommended heparin rinse of the extracorporeal circuit (ECC) prior to the procedure affects thrombogenicity, complement activation, and leukocyte count in blood during continuous venovenous hemodiafiltration (CVVHDF). Eleven critically ill ARF patients were treated, in random order, using CVVHDF in postdilution setup following ECC rinse with saline (A) with heparin at a concentration of 2,000 IU/L (10 procedures), (B) with heparin at a concentration of 10,000 IU/L (7 procedures), and (C) without heparin (9 procedures). Except for the rinse, anticoagulation therapy did not differ in individual patients during the procedures. Blood was withdrawn before, and at minutes 15, 60, and 360 invariably at diafilter inlet and outlet. Compared with healthy individuals, patients showed lower blood thrombocyte counts (153 vs 233*10(9)/L, p<0.01, arithmetic means, Student's t test), longer aPTT (44 vs 36 s, p<0.05), higher plasma levels of heparin (0.1 vs 0.0 U/mL, p<0.05), D-dimer (1129 vs 36 ng/mL, p<0.001) and beta-thromboglobulin (BTG) (159 vs 37 U/mL, p<0.001) prior to CVVHDF. The comparison of procedures with different rinsing technique did not reveal any significant difference in their effects on blood thrombocyte and leukocyte counts, aPTT, plasma levels of heparin, BTG, thrombin-antithrombin III complexes, D-dimer, or the C5a complement component. CONCLUSIONS: (1) Patients indicated for CVVHDF show impaired hemostasis involving thrombocytes, coagulation, and fibrinolysis, (2) no beneficial effect of heparin rinse on CVVHDF ECC thrombogenicity, complement activation or blood leukocyte counts was demonstrated.

[Effect of a dialysis solution with icodextrin on ultrafiltration and selected metabolic parameters in patients treated with peritoneal dialysis]. / Vliv podání dialyzacního roztoku s icodextrinem na ultrafiltraci a vybrané metabolické parametry nemocných lécených peritoneální dialýzou.

BACKGROUND: To date, peritoneal dialysis has been performed almost exclusively using dialysis solutions containing glucose as the osmotic agent. Use of these solutions is fraught with problems regarding adequate fluid removal from the body and is also associated with undesirable metabolic effects; hence the search for alternative osmotic agents. A dialysis solution with the glucose polymer icodextrin generates ultrafiltration on the principle of colloidal osmosis. The aim of the study was to establish the effect of icodextrin-base dialysis solution on the magnitude of ultrafiltration and evaluate selected metabolic parameters of patients treated by ambulatory peritoneal dialysis. METHODS AND RESULTS: A total of 9 patients whose glucose-based solution was replaced by an icodextrin-based solution during the night-time exchange were evaluated. A control group of 9 patients used glucose-solution during all exchanges. Night-time bag ultrafiltration, blood pressure, and the serum levels of lipids, insulin, leptin, maltose, and amylase were determined before icodextrin administration (time 0), at one-month intervals (time 1, 2, 3), and one month after study completion (time 4). In icodextrin-treated patients, ultrafiltration rose from 246.5 +/- 60.5 ml (mean +/- SEM) at time 0 to 593.1 +/- 87.4 ml; p < 0.01, at time 1, to 547 +/- 67 ml; p < 0.05, at time 2, and to 586.7 +/- 58.8 ml; p < 0.01, at time 3, the icodextrin administration led to a rise in maltose from 0.02 +/- 0.01 g/l at time 0 to 0.1 +/- 0.1 g/l; p < 0.01, at time 1, to 1.0 +/- 0.09 g/l; p < 0.01, at time 2, and to 1.1 +/- 0.09 g/l; p < 0.01, at time 3, with a fall to zero values at time 4 (NS). Icodextrin administration was followed by a decrease in leptinemia from 34.6 +/- 17.2 ng/ml at time 0 to 21.7 +/- 8.9 ng/ml; p < 0.05, at time 1, to 21.4 +/- 9.5 ng/ml; p < 0.05, at time 2, and to 15.9 +/- 24.1 ng/ml; p < 0.05 at time 4. Insulin and lipid levels were not affected. There was no change in the above parameters in the control group. Icodextrin-treated patients reduced their antihypertensive medication, but not statistically significantly. CONCLUSION: Icodextrin administration significantly increase ultrafiltration thus providing for effective control of hydration status without the need for high-level glucose-based dialysis solutions. The use of a glucose polymer-based dialysis solution is associated with a significant yet reversible rise in serum maltose. The decrease in leptin may signal a reduction in body weight after replacing glucose in dialysis solutions with icodextrin, or enhanced rates of leptin elimination as a result of ultrafiltration-induced convective transport.

Effects of a vitamin E-modified dialysis membrane and vitamin C infusion on oxidative stress in hemodialysis patients.

Hemodialysis deteriorates oxidative stress. Vitamin E is an antioxidant whose regeneration is provided for by vitamin C. The authors tested the effects of a vitamin E-modified membrane (E), nonmodified cellulose membrane (O), and vitamin C infusion (500 mg, C) into the arterial blood line during dialysis on parameters of oxidative stress. In a short-term study, 24 patients were subjected to a single dialysis session with E, O, E with C, and O with C protocols. In a long-term study (12 weeks), 20 patients were randomized into groups with C and without C on each dialysis, and both groups had dialysis using O, E, and again O membrane for 4 weeks each. In the short-term study, thiobarbituric acid reacting substances (TBARS) in plasma rose after dialysis (p < 0.02) with O, and no changes were observed in the other 3 protocols. In the long-term study, predialysis TBARS declined when using E both in the groups with C (p < 0.02) and without C (p < 0.05). A switch over to O resulted in TBARS returning to baseline levels. The E membrane prevented an increase in lipid peroxidation during single dialysis, and long-term use of the E membrane also resulted in a decrease in the predialysis lipid peroxidation level. The antioxidant capacity of the E membrane was not enhanced by vitamin C infusion. High doses of vitamin C administered during dialysis using a nonmodified cellulose membrane prevented an increase in lipid peroxidation, most probably due to the enhanced rate of endogenous vitamin E regeneration.

[Paired filtration dialysis and free radicals]. / Párová filtracní dialýza a volné radikály.

BACKGROUND: Extracorporeal dialysis compensating kidney function represents a risk of elevated production of free radicals (FR). Paired filtration dialysis (PFD) is a hemodialysing method used to compensate kidney function. The aim of our work was to study effects of PFD with two types of hemodiafilters on the activity of free radicals. METHOD AND RESULTS: Group of nine regularly dialysed patients was treated with PFD 1) with demodiafilter SG3, composed of polysulphone high-flux hemodiafilter and hemophane low-flux dialysator, 2) with hemodiafilter SG30, composed of identical hemodiafilter as the above on and of a polysulphone low-flux dialysator. Parameters related to FR were examined before, at 30th minute and at the end of procedure. Plasma concentration of substances reacting with thiobarbiturate acid (TBARS) increased at 30th minute when PFD with SG3 was used (3.24 +/- 0.36 versus 3.48 +/- 0.31, p < 0.01) and at the end of the procedure (3.24 +/- 0.36 versus 3.58 +/- 0.48, p < 0.05). Glutathione values in erythrocytes (GSH) decreased at 30th minute of PFD with SG3 (1.85 +/- 0.27 versus 1.68 +/- 0.20, p < 0.05). Plasma antioxidative capacity decreased at 30th minute and at the end of PFD with equal significance when either type of treatment was used (p < 0.001). Glutathione peroxidase (GSHPx) decreased at 30th minute of PFD with SG30 (35.6 +/- 3.8 versus 32.2 +/- 3.1, p < 0.05). Selenium (Se) in blood decreased at 30th minute (44.9 +/- 5.4 versus 40.4 +/- 5.9, p < 0.05) and at the end of PFD with the same membrane (44.9 +/- 5.4 versus 39.4 +/- 5.2, p < 0.05). CONCLUSIONS: Elevation of TBARS and decrease of GSH show the presence of oxidative stress during the PFD treatment with hemodiafilter SG3. Changes probably result from the contact of blood with the hemophane membrane. The decrease of GSHPx during PFD with hemodiafilter SG30 is probably caused by the loss of Se. From the point of FR production, hemodiafilter SG30 can be considered as more advantageous, from the point of Se loss and decreased activity of GSHPx, hemodiafilter SG3 has better effects.

Serotonin and 5-hydroxyindole-acetic acid.

BACKGROUND: In patients suffering from chronic renal insufficiency (CRI) serotonin (5HT) metabolism is impaired, and plasma 5-hydroxyindoleacetic acid (5HIAA) levels (main metabolite of 5HT) are increased. AIM: In this study we aimed to give a detailed description of peripheral serotonin metabolism in healthy subjects and patients with CRI, and to evaluate the efficacy of hemodialysis in the elimination of cumulated 5HT and 5HIAA. METHODS: 5HT (platelet rich plasma, platelet poor plasma, urine, HPLC with electrochemical detection) and 5HIAA (plasma, urine, HPCL with electrochemical detection) levels were evaluated in 14 conservatively treated (CT) and 12 hemodialysed (HD) patients with CRI and were compared to those of 60 healthy volunteers (HV). RESULTS: In patients with CRI accumulation of 5HT and 5HIAA in plasma with no changes in platelet 5HT content was revealed. 5HT renal and fractional excretion (FE) was markedly decreased in CRI. FE-5HT was < 1 in all investigated subjects, indicating its reabsorption in proximal tubules, or local degradation to 5HIAA. Due to the increased filtration load renal excretion of 5HIAA was not altered in CT patients, however it was decreased in HD patients. The relative participation of glomerular filtration in 5HIAA renal excretion increased in CRI. FE-5HIAA > 5 was found in 20% of HV and 15% of CT, pointing indirectly to 5HIAA intrarenal production. In CRI FE-5HIAA decreased. HD did not eliminate accumulated 5HT and 5HIAA effectively. CONCLUSION: Increased levels of 5HT and 5HIAA might exert metabolic effects contributing to the clinically manifested impairments characteristic for uremic syndrome. (Tab. 3, Fig. 3, Ref. 27.)

The effect of hemodialysis and acetate-free biofiltration on anemia.

The authors monitored, for a period of 12 months, anemia-, nutrition-, and free radical-related parameters and the rHuEPO dose required to maintain target hemoglobin (Hb) in 20 patients with chronic renal failure. Ten patients each were randomized for treatment by either acetate-free biofiltration (AFB) or low-flux hemodialysis (HD). At baseline, Hb levels were 102+/-2 (AFB) vs. 98+/-2 g/L (HD) (not significant difference, NS), the rHuEPO dose was 4050+/-976 vs. 5100+/-1538 lU/week (NS). Compared with baseline and with HD, lower rHuEPO doses were required during AFB at months 8, 9, 10 and 11, and 12 when they were 2100+/-510 (AFB) vs. 6000+/-1153 (HD), p=0.008. Prealbumin, transferrin and cholinesterase levels rose in the AFB group. Kt/V, albumin, transferrin saturation, aluminium, bicarbonate in serum, superoxide dismutase and glutathione peroxidase in erythrocytes, and malondialdehyde and antioxidant capacity in plasma did not differ between the AFB and HD groups. In terms of anemia control, AFB using an AN69 membrane was found to be more advantageous than low-flux HD, AFB improves some nutritional parameters. The compared methods do not differ in their effect on lipid peroxidation and the antioxidant system.

[The role of cytokines in peritoneal dialysis]. / Uloha cytokinu pri peritoneální dialýze.

Peritoneal dialysis is a method of renal replacement therapy which has been increasingly in use worldwide and, in recent years, also in our country. A factor limiting long-term use of peritoneal dialysis is the maintenance of the function of the peritoneum as a dialysis membrane. Impairment of the anatomical and functional integrity of the peritoneal membrane may be due to severe or recurrent peritonitis but, also, in patients without a history of peritoneal infection, presumably as a result of contact between the peritoneum and a bioincompatible dialysis solution. When investigating the structural and functional changes in the peritoneal membrane, considerable attention was given to cytokines. The main source of cytokines in the peritoneal cavity are macrophages, mesothelial cells, and fibroblasts. In peritoneal dialysis, cytokines play a role both in defense against the development of peritoneal infection and in the course of peritoneal infection. By virtue of their biological effects, cytokines may affect the permeability of the peritoneal membrane and, consequently, the efficacy of peritoneal dialysis. In addition, cytokines are released on contact of the peritoneum with the dialysis solution and may thus be made use of in biocompatibility studies. Changes of cytokine levels can be studied--when performing peritoneal dialysis in clinical practice--in the dialysis solution drained from the peritoneal cavity, in tissue cultures, and in animal experiments. The effects of cytokines are modified by the action of their soluble receptors and antagonists. Future studies are warranted to clarify the role of cytokine antagonists and their soluble receptors.

Oxidative stress: the effect of erythropoietin and the dialysis membrane.

Dialysis patients run the risk of impaired antioxidative defense and increased free radicals (FR) production. The study was made in order to compare FR-related parameters in ten patients treated with erythropoietin (EPO+) and ten patients not subject to this treatment (EPO-). All patients showed stable hemoglobin levels at > 95 g/L. FR-related parameters were monitored during hemodialysis (HD) using a polysulfon (PS) or a hemophan (H) membrane for 12 of them (6 EPO+ a 6 EPO-). The EPO- group was found to have a higher activity of superoxide dismutase (SOD, 1160 + 218 vs; 882 + 125 IU/gHb, p<0.01) and a higher SOD/glutathione peroxidase (GSHPx) ratio compared with EPO+ (30.5 +/- 7.1 vs; 21.2 + 4.8, p<0.01). A total of 35 healthy volunteers were also examined. When compared with controls EPO- showed higher SOD (p<0.001), lower GSHPx (p<0.05) and a higher SOD/GSHPx ratio (p<0.001). Thiobarbituric acid reacting substances in EPO+ and EPO- were comparable with the levels found in controls. HD using H as well as PS membranes was associated with a decrease in erythrocyte glutathione levels (GSH after 30 minutes; also for H after HD). HD using H and PS membranes resulted in a decrease in the plasma antioxidant capacity (AOC). We can conclude that the intraerythrocyte antioxidant conditions of EPO+ patients are similar to those found in the general population and differ from those in EPO- exhibiting increased SOD and the SOD/GSHPx ratio. HD using the H as well as the PS membrane is accompanied by oxidative stress.

[Renal anemia and the effect of long-term dialysis]. / Renální anémie a úcinnost dlouhodobé dialýzy.

Renal anaemia causes in patients with chronic renal failure numerous serious problems which can be favourably influenced by improvement of the anaemia. There is a number of known factors which cause deterioration of anaemia and make its treatment more difficult. For a long time it was not clear that these negatively acting factors included also insufficiently effective dialysis treatment. The authors of the submitted paper evaluate the relationship between anaemia and the effectiveness of dialysis based on new data reported in the literature and their own results. From this evaluation ensues that inadequate haemodialysis, assessed from the percentage reduction of urea in blood, is associated with a reduced response to recombinant human erythropoietin which is the basic remedy of renal anaemia. If the inadequate intensity of haemodialysis is increased, anaemia improves substantially. In patients on continuous ambulatory peritoneal dialysis (CAPD) there is a direct relationship between the effectiveness of blood purification expressed by the index KT/Vurea, i.e. the indicator of urea elimination, and the severity of anaemia. In patients treated by CAPD there is a significant association between the haematocrit and KT/Vurea supplied by the peritoneum as well as the kidneys. KT/Vurea supplied by the patient's own kidneys is from the aspect of anaemia more significant. Some facts regarding the relationship between anaemia and the effectiveness of dialysis treatment remain obscure so far. This however does not influence the fact that based on data available at present, effective dialysis must be included among basic prerequisites of effective treatment of renal anaemia in dialyzed patients.

The anemia in continuous ambulatory peritoneal dialysis patients is related to Kt/V index.

Anemia in chronic renal failure causes a number of serious problems to the patient. As a result, it is imperative to make use of all rational options to alleviate it. The present study addresses the question, the answer to which is not yet known, whether or not the degree of anemia depends on the efficacy of continuous ambulatory peritoneal dialysis (CAPD) and, if so, what the importance of peritoneal clearance and residual renal function is. A significant correlation between the hematocrit (Hct) and the total weekly Kt/V index (tKt/V) (r = 0.61, p<0.01), total weekly creatinine clearance (tCLCR) (r = 0.50, p<0.05), and residual glomerular filtration rate (r = 0.43, p<0.05) was demonstrated in a group of 22 CAPD patients. Stepwise regression analysis showed that of all the variables monitored, Hct depends exclusively on tKt/V (p<0.01, r2 = 0.37). The value of Hct in a group of patients with a tKt/V <2.3 (n = 15) was 28.9+/-1.2% (arithmetic mean +/- SEM) while in a group with a tKt/V > or =2.3 (n = 7), it was 35.1+/-1.9% (p<0.01). On dividing tKt/V and tCLCR into their peritoneal and renal components, a significant correlation between Hct and renal Kt/V (r = 0.47, p<0.05) was found; stepwise regression analysis identified renal Kt/V (p<0.01) and peritoneal Kt/V (p<0.05), with R2 = 0.38 as major variables with an effect on Hct. The authors conclude the efficacy of blood purification is another factor affecting renal anemia in CAPD patients. The relationship between anemia and blood purification is best expressed using the Kt/V index. The Kt/V provided by one's own kidneys seems to be of greater importance for anemia than the Kt/V provided by peritoneal dialysis. The results provide the basis for prospective interventional studies.

A prospective randomised European multicentre study of medium-long run mortality and morbidity comparing acetate-free biofiltration and bicarbonate dialysis.

In recent years, the progressive increase in the mean age of the population entering chronic dialysis treatment has been responsible, on the one hand, for the growing number of patients undergoing regular dialysis, and on the other, for the high number of "critical" patients, both as a result of their age and the presence of concomitant morbidity. Thus, dialysis treatment today is not only aimed at waste removal and water-electrolyte homeostasis, but also at a reduction in morbidity and mortality, and at improving the patients' quality of life, thanks to the use of biocompatible materials and the achievement of good cardiovascular tolerance to treatment. Consequently, diffusive-convective dialysis procedures have been on the increase, since they combine better depuration with the use of biocompatible high-flux membranes. Acetate-free biofiltration (AFB) is a diffusive-convective dialysis procedure which utilises a high-flux membrane, AN69, post-dilution infusion of a sodium bicarbonate solution (NaHCO3), and a dialysate which is completely free of any buffer, and thus also free of acetate, which may have various negative effects on the patient. A number of studies have already shown the better hemodynamic stability and the reduction of intradialytic side-effects during AFB. All these, however, were short-term studies. To verify the beneficial effects of AFB in the long run, a three year multicentre randomised European trial has been proposed to compare bicarbonate hemodialysis (BD), a technique used in nearly 80% of the world's dialysis population, and AFB. The specific aim of the investigation is to verify, in a large number of patients, the results of hemodialysis treatment in terms of morbidity, mortality and quality of life. The study involves 80 hemodialysis units across Italy, France, Germany, Spain, Slovenia and Croatia, with enrollment of about 400 patients considered "critical" for at least one of the following reasons: age, diabetes, dialysis cardiovascular instability. Fifty percent of the patients are to undergo AFB with the AN69 membrane and bicarbonate solution infusion (NaHCO3 145 or 167 mEq/lt), and the other fifty percent are to be treated by BD, with any membrane except the nonmodified cellulosic one. Biochemical, cardiological, and nutritional parameters will be considered throughout the study. Mortality, morbidity both in terms of intra- and interdialysis symptoms - and hospitalisation rate, as well as the patients' quality of life, evaluated by the SF36 questionnaire, will be analysed.