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.

Hemostasis disorders in chronic renal failure.

Dialysis patients with CRF show a fibrinolysis defect at the level of plasminogen activation. The fibrinolysis defect in CRF deepens as renal function declines. Reduced fibrinolysis may be responsible, along with other factors, for the development of thrombosis, atherosclerosis and their thrombotic complications. A number of important and relevant questions, which are more or less interrelated, continue to be left without clear-cut answers. These include, for instance, what is the relationship between fibrinolysis defects in CRF and "prothrombotic" metabolic disorders? To what extent, if at all, does hypofibrinolysis normalize during treatment of these metabolic disorders? Indeed, is there a causative relationship between the decrease in fibrinolysis and thrombotic complications in patients with CRF?

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.

Serum hippurate and its excretion in conservatively treated and dialysed patients with chronic renal failure.

54 healthy volunteers or patients with normal kidney and liver function, 17 patients with decreased kidney function and 12 dialysed patients were evaluated for their serum hippurate accumulation and kidney excretion. It was found that there was an inverse relationship between serum hippurate and the clearance of endogenous creatinine (CCr) and a free relationship between fractional excretion of hippurate and CCr. The excretory capacity in residual nephrons was increased. This was caused by the greater glomerular filtration load which increased up to 25 times and tubular secretion which increased 7 times in dialysed patients. The relative contribution of glomerular filtration to hippurate excretion rose from about 20% in controls to almost 50% in dialysed patients. True kidney adaptation was localized in the organic anion transport system of proximal tubules.

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.

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.

A clinical study to assess the effect of heparin in dialyzer rinsing solutions.

The solution usually recommended for rinsing the blood side, which is an indispensable step in preparing a dialyzer for hemodialysis (HD), contains saline and heparin. The heparin used for rinsing is said to reduce the thrombogenic properties of the dialysis membrane and, hence, also the need for systemic heparinization during the whole procedure. The aim of our study was to establish whether this postulate also applies to polysulphone steam-sterilized dialyzers. To do so, 16 patients on long-term dialysis were randomized into two groups of eight. One group was subsequently treated with polysulphone low-flux dialyzers (F6HPS), the other with polysulphone high-flux dialyzers (F6OS). Both groups were examined, in a crossover manner during HD using a dialyzer previously rinsed with 1000 ml of saline plus 2,000 IU of heparin, and during HD using a dialyzer previously rinsed with 500 ml of saline without heparin. Except for the rinsing, HD conditions were completely identical. Blood obtained before HD, and at 15, 60 and 240 min of HD at the dialyzer inlet, was used to determine the activated partial thromboplastin time (to test heparinization control), the thrombin-antithrombin III complex (ELISA, to evaluate coagulation system activation), platelet factor 4 (ELISA, a substance with antiheparin activity), and platelet count. None of the above parameters showed, at any of the collecting intervals, a statistically significant difference between HD with and without heparin with a reduced volume of rinsing solution, or between HD using low- and high-flux dialyzers. It is concluded that heparin used to rinse polysulphone dialyzers before HD has no effect on blood coagulation or on the need for heparin during the procedure.

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.

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.

Spontaneous renal allograft rupture. Clinical and pathological patterns.

Rupture of an allografted kidney occurred in five patients 5-17 days after transplantation. In one patient the microscopic pathological changes corresponded with the nodose polyarteritis pattern. In four patients interstitial rejection nephritis with severe haemorrhage and haematoma was found. It is suggested that the bleeding is due to peristatic hyperaemia and defects in the inner elastic membranes. In one case multifocal necrotizing arteriopathy was the main pathogenetic factor.

[Relation between blood glucose and insulin in hemodialysis]. / Vztahy glykémie a inzulínu pri hemodialýze.

In 25 patients with chronic renal failure, the levels of glycemia and immunoreactive insulin (IRI) were determined in one-hour intervals over the period of eight-hour hemodialysis. The study was performed in hemodialysis with and without 200 mg% glucose in the dialysis solution. The mutual behavior of the two substances was evaluated. In patients on a chronic hemodialysis program the level of IRI was found to depend on elimination, secretion, and endogenous control of IRI. The internal processes may be involved to a more important extent in achieving the definitive levels of IRI (middle-molecular substance) than its elimination by hemodialysis. The actual regulator-glucose (low-molecular substance) need not change its level significantly in this process.

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.)

[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.

[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.

[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.

[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.

[Does therapeutic membrane plasmapheresis increase protein synthesis?]. / Urychluje lécebná membránová plazmaferéza proteosyntézu?

The objective of the investigation was to assess whether therapeutic membrane plasmapheresis accelerates protein synthesis. To this end pseudouridine (PSI), a modified nucleoside was investigated which provides information on the tRNA turnover and thus indirectly also on protein synthesis. The authors made 10 plasmapheresis on a A 2008 PF monitor with Plasmaflux P2 filters which they use to exchange 1 plasma volume of the patients. Laboratory indicators were investigated one day before plasmapheresis, on the day of plasmapheresis and during its course, and on the 1st, 2nd and possibly 3rd day after plasmapheresis. They revealed that the clearance of the plasma filter for PSI (0.41 +/- 0.04 ml/s, arithmetical mean +/- SEM) did not differ significantly from the filtration rate (0.49 +/- 0.01 ml/s, p = 0.15). As compared with the initial examination (0.49 +/- 0.06 ml/s) on the first day after plasmapheresis as a result of reduced glomerular filtration rate the renal clearance of PSI was reduced (0.33 +/- 0.05, p less than 0.01). PSI serum concentrations were therefore expressed as the serum PSI/serum creatinine ratio. This ratio was, as compared with the initial examination (80.4 +/- 4.8 nmol/mumol), raised midway during the procedure (100.8 +/- 8.6, p much less than 0.05) and after its termination (132.3 +/- 6.1, p much less than 0.01). The increase was not due to disintegration of cells or dietary factors. The rise of the serum PSI/serum creatinine ratio was due to a more rapid tRNA turnover and thus provided evidence that therapeutic membrane plasmapheresis accelerates protein synthesis.

[Results of studies of indicators of hemostasis in hemodialyzed patients during administration of 1-deamino-8-D-arginine vasopressin]. / Výsledky vysetrení nekterých ukazatelu hemostázy u hemodialyzovaných nemocných pri podání 1-deamino-8-d-arginin vasopresinu.

The fibrinolytic activity (FA) evaluated according to the euglobulin clot lysis time was in haemodialyzed patients (3.0 +/- 0.2 arb. u.) lower than in patients with chronic renal failure treated by conservative methods (4.7 +/- 0.6, p less than 0.05) and than in healthy subjects (4.2 +/- 0.4, p less than 0.05). After stimulation by intravenous administration of 1-deamino-8-D-arginine vasopressin the FA in haemodialyzed patients rose to (4.5 +/- 1.6), less than in conservatively treated (14.1 +/- 2.1, p = 0.06) and than in healthy subjects (18.2 +/- 3.9, p less than 0.001). By using specific methods it was proved that the inadequate rise of FA in haemodialyzed patients after stimulation is conditioned by a defect of the release of the plasminogen tissue activator from the vascular wall. Contrary to healthy subjects (7.0 +/- 1.3 vs. 16.7 +/- 2.3 ng/ml, p less than 0.01) is plasma concentration in haemodialyzed subjects (5.3 +/- 0.5 vs. 7.9 +/- 0.8, NS) did not increase significantly. Repeated examinations of some of the haemodialyzed patients revealed that almost 20 months of regular haemodialysis do not lead to further changes of basal (2.9 +/- 0.3 vs. 2.8 +/- 0.2) nor stimulated (4.2 +/- 0.5 vs. 4.8 +/- 0.9) FA. Basal plasma concentrations of the von Willebrand factor were in the dialyzed patients (89.1 +/- 8.8%) higher than in healthy subjects (67.2 +/- 4.4, p less than 0.05). After stimulation the concentration of the von Willebrand factor increased significantly in healthy subjects (99.1 +/- 4.3, p less than 0.01), but not in dialyzed patients (82.9 +/- 3.1, NS), obviously due to the pathological reactivity of their vascular wall. The above findings may be associated with thromboses and atherosclerosis in patients on long-term dialysis.

[The effect of acetate-free biofiltration on anemia and use of erythropoietin]. / Vliv bezacetátové biofiltrace na anémii a spotrebu erytropoetinu.

BACKGROUND: Chronic renal failure is associated with anaemia and a large percentage of patients is indicated for erythropoietin (rHuEPO) treatment. The degree of anaemia depends also on the quality of substitution of renal function. The objective of the present study was to assess whether transfer of patients from haemodialysis (HD) to acetate-free biofiltration (AFB) will influence the anaemia and rHuEPO consumption. METHODS AND RESULTS: Anaemia and rHuEPO consumption were investigated in 10 patients in a stabilized condition with regular dialyzation treatment. The patients suffered from corrected anaemia on a maintenance dose of rHuEPO. During AFB (follow-up period one year) the rHuEPO consumption declined as compared with the condition during HD, while the target haemoglobin level (95-110 g/l) was maintained. The easier control of anaemia during AFB was not due to a change of iron saturation, the aluminium level or a change of the residual blood volume in the dialyzer. During AFB metabolic acidosis was controlled more effectively, the elimination of urea and beta-2-microglobulin increased. CONCLUSIONS: During AFB, as compared with HD, the rHuEPO consumption declines sufficiently to correct anaemia. The authors conclude that one of the reasons may be the more effective control of metabolic acidosis and elimination of uraemic toxins with a low or medium molecular weight. The authors discuss also other factors which affect anaemia during treatment of renal failure by extracorporcal clearing methods.

[The effect of erythropoietin on fibrinolysis in hemodialyzed patients]. / Vliv erytropoetinu na fibrinolýzu u hemodialyzovaných nemocných.

BACKGROUND: According to some data treatment with human recombinant erythropoietin (EPO) in dialyzed patients leads to a more frequent occurrence of thromboses. One of the possible causes could be reduced fibrinolysis. The objective of the present study was to assess the effect of EPO in dialyzed patients on two key enzymes of fibrinolysis, i.e. the tissue activator of plasminogen (t-PA) and the inhibitor of the plasminogen activator (PAI-1). METHODS AND RESULTS: In eight patients dialyzed for prolonged periods examined under otherwise equal conditions before EPO treatment (haematocrit 22.9%--median value) and after 9.5 weeks of EPO treatment (Recormon, s.c.) when a haematocrit of 30% was achieved, activities (chromogenic substrates) and antigens (ELISA of t-PA and PAI) were assessed. All examinations were made before and after venous occlusion. Between examinations made before treatment and during EPO treatment no significant difference was found in the t-Pa activities assessed before venous occlusion (before EPO 0.9 IU/ml--during EPO 0.6, not significant Wilcoxon's paired test) nor after venous occlusion (3.2-3.8, n.s.). PAI activities before venous occlusion (10.9 U/ml-18.3, n.s.) and after venous occlusion (9.7-11.5, n.s.) did not differ significantly either, when comparing values before and in the course of EPO treatment. Similarly as in the case of activities in antigens t-PA and PAI no difference was found before and during EPO. CONCLUSIONS: No effect of EPO on the investigated indicators of fibrinolysis was found. The results of the presented investigation are at variance with the idea that EPO reduces fibrinolysis in dialyzed patients and thus contributes to the development of thrombotic complications.