[Differential diagnosis and treatment of hyponatremia]. / Diferenciálna diagnóza a liecba hyponatriémie.

Hyponatremia is one of the most common metabolic disorders in clinical medicine. The value of Na+ in serum equalling 135 mmol/ l and lower is regarded as hyponatremia. Its clinical manifestations are the following: headaches, nausea, vomiting, seizures, numbness, coma and death. Hyponatremia caused by nonosmotic hypersecretion of vasopressin can be divided into: a) hypovolemic, b) normovolemic and c) hypervolemic. Hyponatremia which is not caused by the hypersecretion of vasopressin is the so  called pseudohyponatremia, water intoxication, cerebral salt loss syndrome. Hypovolemic hyponatremia is caused by the loss of Na+ and fluid loss from the organism. It occurs, for example, after using thiazide diuretics, after recurrent diarrhoea, vomiting, after significant blood loss and other causes. Treatment of this disorder must focus on the producing cause and on the parenteral administration of 0.9% NaCl. Normovolemic hyponatremia can be with or without symptoms. Acute normovolemic hyponatremia is treated by the intravenous administration of 3% NaCl and with the simultaneous use of loop diuretics (20- 40 mg Furosemide/ 24 hrs) and restriction of fluid intake. In the case of chronic normovolemic hyponatremia, refractory to the previous treatment, caused by the inappropriate secretion of arginine  vasopressin, it is recommended to use perorally its V2- receptor blocker, Tolvaptan. Hypervolemic hyponatremia occurs in the case of cardiovascular failure, with hepatic cirrhosis, nephrotic syndrome, renal failure, porphyric disease and other conditions. Symptoms occurring with it are swellings, ascites, distension of jugular veins and the presence of unaccented rales in the lungs, which can be detected during physical examination. For treatment it is recommended to restrict fluid intake and to administer NaCl as well as diuretic therapy. Recently it has been recommended to use Tolvaptan which increases excretion of free water (aquaresis), decreases osmolality in the urine, and leads to the increase in serum Na+. Apart from that, we present our three clinical  laboratory observations in the paper: 1. Contrary to the data in the literature, after the Kosice Marathon (42.125 km) the serum concentration of Na+ in the runners increased (from 144.4 ± 2.1 mmol/ l to 147 ± 2.8 mmol/ l, p < 0.01) in spite of a significant reduction in the body weight (from 73.2 ± 5.7 kg to 71.9 ± 5.2 kg, p < 0.05), intensive perspiration and dehydration (blood haemoglobin before the run: 150.4 ± 5.5 g/ l, after the run: 152.1 ± 4.8 g/ l, p < 0.05). Apart from that, we detected a significant decrease in the fractional excretion of sodium (FENa) from 1.16 ± 0.30% to 0.34 ± 0.10%, p < 0.01. 2. One patient with chronic intermittent porphyria displayed the syndrome of inappropriate antidiuretic hormone secretion, which had been positively influenced by the restriction of fluid intake in the long term and by peroral administration of 1- 3 g NaCl/ 24 hrs. 3. In 15 haemodialysed patients with chronic renal failure, who displayed recurrent hypervolemic hyponatremia, we achieved, by means of adequate ultrafiltration and a dialysis solution containing Na+ 145 mmol/ l, the serum concentration of Na+ 142 mmol/ l at the end of haemodialysis.

[Oxalic acid--important uremic toxin]. / Kyselina oxalová--významný uremický toxín.

INTRODUCTION: Oxalic acid is thought to be a significant uremic toxin that participates in the pathogenesis of uremic syndrome. AIM OF THE STUDY was to summarise results which we obtained during the study ofoxalic acid in biological fluids (plasma, saliva, urine and dialysate) in patients suffering from chronic kidney diseases (CKD), stage 3-5 and after renal transplantation. PATIENTS AND METHODS: In the retrospective study were investigated 28 healthy subjects, 112 CKD stage 1-4 patients, 39 haemodialysis patients and 27 CAPD patients. Besides 21 patients were investigated after renal transplantation. We used the following therapeutic methods: maximal water diuresis, diet with low (2g/day) and high (15g/day) sodium chloride intake, administration intravenous furosemide (20mg) and renal replacement therapy [CAPD, haemodialysis (HD), haemofiltration (HF) and postdilution haemodiafiltration (HDF)] and renal transplantation. Oxalic acid was determined by spectrophotometric method using oxalate oxidase which is free from vitamin C interference. Vitamin C was determined by spectrophotometric method. RESULTS: In CKD patients and those after renal transplantation direct relationships between plasma oxalic acid and serum creatinine were found (r = 0.904 and 0.943, respectively, P < 0.001). Despite of high plasma oxalic acid in uremic patients (23.1 +/- 10 micromol/l), there was no significant difference in salivary oxalic acid between control subjects (126.5 +/- 18 micromol/l) and CKD stage 3-4 patients (133.9 +/- 23.7 micromol/I). The urinary excretion of oxalic acid during maximal water diuresis in healthy subjects (n = 15) (from 37.5 +/- 17.4 to 110.2 +/- 49.3 micromol/4 hours) and after intravenous furosemide (CKD stage 3-4, n = 15) (from 34.5 +/- 5.5 to 66.7 +/- 8.1 micromol/3 hours) increased significantly, but was not affected by high intake of NaCI in diet (CKD stage 3-4, n = 12). One tablet of Sorbifer Durules containing 100 mg Fe2+ and 60 mg vitamin C did not lead to further increase of uremic hyperoxalemia in haemodialysis patients. Four-hour HD, H F and HDF led to the significant decrease of plasma oxalic acid, but the most significant decrease was observed during HDF (63.3%). CONCLUSION: The results of this study indicate, that renal replacement therapy is not effective for permanent reduction of elevated plasma levels of oxalic acid--important uremic toxin.

[Professor Frantisek Por MD and Professor Robert Klopstock MD, students at Budapest and Prague Faculties of Medicine]. / Profesor MUDr. Frantisek Pór a Profesor Dr. Med. Robert Klopstock, poslucháci Lekárskych fakúlt v Budapesti a v Prahe.

Professor Frantisek Por MD and Professor Robert Klopstock MD were contemporaries, both born in 1899, one in Zvolen, the other in Dombovar, at the time of Austro-Hungarian Monarchy. Prof. Por attended the Faculty of Medicine in Budapest from 1918 to 1920, and Prof. Klopstock studied at the same place between 1917 and 1919. From 1920 until graduation on 6th February 1926, Prof. Por continued his studies at the German Faculty of Medicine, Charles University in Prague. Prof. Klopstock had to interrupt his studies in Budapest due to pulmonary tuberculosis; he received treatment at Tatranske Matliare where he befriended Franz Kafka. Later, upon Kafka's encouragement, he changed institutions and continued his studies at the German Faculty of Medicine, Charles University in Prague, where he graduated the first great go. It is very likely that, during their studies in Budapest and Prague, both professors met repeatedly, even though their life paths later separated. Following his graduation, Prof. Por practiced as an internist in Prague, later in Slovakia, and from 1945 in Kosice. In 1961, he was awarded the title of university professor of internal medicine at the Faculty of Medicine, Pavol Jozef Safarik University in Kosice, where he practiced until his death in 1980. Prof. Klopstock continued his studies in Kiel and Berlin. After his graduation in 1933, he practiced in Berlin as a surgeon and in 1938 left for USA. In 1962, he was awarded the title of university professor of pulmonary surgery in NewYork, where he died in 1972.

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.

[Professor MUDr. Frantisek Pór's School of Internal Medicine]. / Internistická skola profesora MUDr. Frantiska Póra.

The article pays tribute to prof. MUDr. Frantisek Pór and his significant role in the development of internal medicine in Kosice and in Eastern Slovakia, where he actively pursued his profession from 1945 to 1971. He was the founder of the school of internal medicine in the proper sense of the word having laid down its organisation, therapy and prevention, training and research bases. His pupils, and the pupils of his pupils, have carried on his legacy till this day. This fact was remembered on the occasion of the 15th commemoration held by the Kosice Doctors' Association in his honour and memory and on the occasion of the upcoming 60th anniversary of the foundation of the Faculty of Medicine at Pavol Jozef Safárik University in Kosice.

[Contribution of Department of Nephrology of L. Pasteur Teaching Hospital and the UPJS Medical Faculty, Kosice (SK), to Czech nephrology]. / Prispevok nefrológie vo fakultnej nemocnici L. Pasteura a Lekárskej Fakulty Univerzity P. J. Safárika v Kosiciach ku histórii ceskej nefrológie.

The paper deals with the contribution of L. PasteurTeaching Hospital and the UPJS Medical Faculty, Kosice, to Czech nephrology studies between 1954 and 2006. Specific reference is made to cooperation with different clinics, wards and institutes in Prague, Hradec Králové, Pilsen and Brno in the sphere of therapeutic and proactive care, teaching activities, lecturing and publishing activities, as well as active involvement in research projects. Cooperation in all the above spheres attained and maintained high level, promoted the creation of friendly relations between Czech nephrology experts and the staff of the 1 st and 4th Internal Clinics and, beginning with 1997, of the Clinic of Nephrology, fostered solidarity between the two nations and has been to a great extent sustained to this day.

Robert Klopstock and Franz Kafka--the friends from Tatranské Matliare (the High Tatras).

The paper summarises the accessible literature on the life and work of well-known American lung surgeon, Professor Dr. Med. Robert Klopstock, who was in the years 1920-1924 a friend Franz Kafka. Professor Klopstock was of Hungarian origin and he got acquainted with Franz Kafka at the end of the year 1920 in Tatranské Matliare (The High Tatras). They were both patients treated for lung tuberculosis. They became close friends and their mutual correspondence shows their real friendship. Robert Klopstock was present at Franz Kafka's death-bed on June 3, 1924 in Kierling, near Klosterneuburg, not far from Vienna. Robert Klopstock studied at Medical Faculties of the Universities in Budapest, Prague, Kiel and Berlin. After his graduation in 1933 in Berlin, he worked as a lung surgeon at various surgical clinics and departments in Budapest and Berlin. In 1936 Robert Klopstock together with his wife visited the High Tatras and Tatranské Matliare. In 1937 Robert Klopstock with his wife Gizela, a writer and a translator, who translated the first chapters of Franz Kafka's novel "Trial" into Hungarian language, went to United States of America. During his stay in U.S.A. Dr. Med. Robert Klopstock was very active as a lung surgeon and a scientist. He published 64 specialized scientific papers, mostly in American medical journals. He became Professor of Lung Surgery at Downstate Medical Centre in New York-Brooklyn. He died on June 15, 1972 in New York.

Antioxidant therapy by oral vitamin E and vitamin E-coated dialyzer in CAPD and haemodialysis patients.

Oxidative stress, increased lipid peroxidation, and impaired function of antioxidant system may contribute to the accelerated development of atherosclerosis in chronic renal failure patients during renal replacement therapy. The aim of the study was to investigate the influence of oral vitamin E (400 mg/day) in 14 patients who underwent continuous ambulatory peritoneal dialysis (CAPD) and effects of the vitamin E-coated dialyzer in 14 haemodialysis patients on several antioxidant biochemical parameters. Six-week treatment with oral vitamin E in CAPD patients and three-month treatment using vitamin E-coated dialyzer in haemodialysis patients led to the significant decrease of plasma malondialdehyde, to the increase of plasma vitamin E and to the increase of erythrocyte vitamin E in haemodialysis patients. No significant changes of erythrocyte antioxidant enzyme--superoxide dismutase, glutathione peroxidase and catalase were found during the both types of antioxidant therapy. At the end of the third month of haemodialysis study the significant increase of erythrocyte glutathione in haemodialysis patients was found, but that value was significantly lower as normal range. Six-week interruption of the administration of oral vitamin E in CAPD patients led to the significant decrease of erythrocyte superoxide dismutase and plasma vitamin E. Ten-week interruption of the use of vitamin E-coated dialyzer led to the significant increase of plasma malondialdehyde and to the decrease of plasma and erythrocyte vitamin E in haemodialysis patients, near to the values at the beginning of the study. Our study confirmed the beneficial effect of oral administration of vitamin E and the use of vitamin E-coated dialyzer against oxidative stress in CAPD and haemodialysis patients.

The disease of Franz Kafka.

On June 3, 2004, 80 years have passed since the death of one of the greatest and the most important world writers of 20th century, the Prague German writer Franz Kafka. On November 5, 2004 we reminded that remarkable anniversary, which was also the 3rd anniversary of revelation of the monument of Franz Kafka in Tatranské Matliare, the High Tatras. Franz Kafka suffered from lung tuberculosis from 1917 until his death 1924. He was treated on lung tuberculosis in the sanatorium "Villa Tatra" from December 20, 1920 until August 27, 1921 in Tatranské Matliare, the High Tatras. Lung tuberculosis was a very dangerous disease in that time and the treatment by dietotherapy, climatotherapy and symptomatic therapy without antituberculotic drugs was less effective in many patients. In the paper the disease of Franz Kafka was described according to available literature.

[Continuous ambulatory peritoneal dialysis and respiratory pulmonary functions]. / Kontinuálna ambulantná peritoneálna dialýza a respiracné funkcie pl'úc.

Acidobasic balance and respiratory pulmonary functions were examined in 15 patients with chronic renal insufficiency during continuous ambulatory peritoneal dialysis (CAPD) using a dialysis solution containing 1.5% or 2.5% of glucose. Patients did not suffer from any pulmonary disease nor ischemic heart disease. Biochemical indicators of acidobasic balance were in reference range or on its lower margin. Respiratory pulmonary functions were in tolerance except maximum expiratory flow volume at 50% and 25% of vital capacity (MEF50 and MEF25) and except diffusion lung capacity (DLCO) which were decreased. Decrease of maximum expiratory flow could be caused by a loss of elasticity of pulmonary parenchyma and by a beginning increased resistance in peripheral pulmonary ways. Decreased DLCO was identified in majority of patients and was caused by anaemia and a minimal interstitial pulmonary edema. Use of a single peritoneal dialysis with dialysis solutions of various glucose concentrations did not have any significant effect on acidobasic balance markers nor pulmonary respiratory functions.

105th birth anniversary of professor Frantisek Pór, M.D.

Professor Frantisek Pór, M.D., was one of the most remarkable physicians in Czechoslovakia. He graduated at the German Medical Faculty of Charles University in Prague, in 1926. He was a founder of the First Internal Clinic of the Medical Faculty of P J. Safárik University and of the Faculty Hospital in Kosice. Prof. F. Pór, M.D., was the Head of the First Internal Clinic from 1948 until 1971. During his active professional life he educated 11 associate professors and 3 full professors. He was also a founder of Eastern Slovakian Medical Meetings in Nový Smokovec, the High Tatras, in 1961. The "Memorial Meeting of Professor F. Pór, M.D." has been organized by the Medical Society in Kosice since 1994. The last one was held in the Faculty Hospital of L. Pasteur in Kosice, on April 28, 2003.

[History of nephrology and extracorporeal drug removal at the L. Pasteur Hospital in Kosice]. / História nefrológie a mimotelovej eliminacnej liecby vo Fakultnej nemocnici L. Pasteura v Kosiciach.

The authors describe the development of clinical nephrology from 1948 to 2002 at the Medical Faculty of the P. J. Safarík University and L. Pasteur Faculty Hospital from the aspect of therapeutic and preventive care, teaching and research activities. The dialysis centre which was established in 1966 at the Medical Clinic of the Faculty Hospital in Kosice continued in the activities as the Nephrological laboratory which was founded in 1954. This laboratory still operates under the conditions of the Nephrological Clinic. In 1964 at the Medical Clinic the first percutaneous renal biopsy was implemented. In 1966 the first peritoneal dialysis was implemented and the first haemodialysis in a patient with chronic renal failure, later gradually all so far known therapeutic methods were introduced which replace renal function and are used in acute and chronic renal failure and in acute intoxication. On March 18, 1977 in the authors' department the first haemoperfusion over active charcoal was made successfully in a patient intoxicated with parquat. It was the first haemoperfusion in the former Czechoslovak Republic. From 1991 at the Clinic a Sub-chair of nephrology and dialysis was established attached to the Institute for Postgraduate Training, later SPAM. Within the framework of the latter several nephrological courses were organized as well as courses in extracorporeal elimination treatment and in acute toxicology. The department acted also as a training place for future nephrologists before the specialization examination in nephrology. Since 1981 successfully several research grants concerned with the use of haemoperfusion over active charcoal and other sorbents in acute intoxications were completed as well as grants focused on metabolic vitamin disorders in chronic renal failure. On October 24 1997 in our department within the framework of the P. J. Safarík University Medical Faculty and L. Pasteur Faculty Hospital the Nephrological Clinic was established, the first one in the Slovak Republic. This stimulated further qualitative development of nephrology not only in Kosice but in the whole of Slovakia.

[Tenth memorial of professor Frantisek Pór, MD]. / X. memoriál profesora MUDr. Frantiska Póra.

Professor Frantisek Pór, MD, was one of the most important physicians in Czechoslovakia. He graduated in German Medical Faculty of Charles University in Prague in 1926. He was a founder of the first Internal Clinic of Medical Faculty of P. J. Safárik University and of Faculty Hospital in Kosice. Professor F. Pór, MD, was the head of the 1st Internal Clinic from 1948 until 1971. During his active professional life he educated eleven assistant professors and three full professors. He was also a founder of Eastern Slovakian Medical Meetings in Nový Smokovec, High Tatras in 1961. Medical Society in Kosice organized "Memorial of Professor F. Pór, MD" from 1994 every year and the last was held in April 28, 2003 in Faculty Hospital of L. Pasteur in Kosice.

Vitamin E as an antioxidant agent in CAPD patients.

Oxidative stress, increased lipid peroxidation and decreased activity of antioxidant systems may contribute to the accelerated development of atherosclerosis in chronic renal failure patients during renal replacement therapy. The aim of the study was to investigate the influence of vitamin E (400 mg/day) on some antioxidant defense parameters in CAPD patients. In fourteen CAPD patients, erythrocyte antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT), the concentration of plasma malondialdehyde (MDA), vitamin A, vitamin C and vitamin E were investigated. The study was divided into two periods. Each period lasted six weeks. In the first period patients received orally vitamin E 400 mg/day, in the second period they did not receive vitamin E or other antioxidant drugs. Each parameter was determined at the beginning of the study and at the end of each period. Six CAPD patients were treated by erythropoietin (EPO) and received orally pyridoxine 20 mg/day and the others without EPO treatment received pyridoxine 5 mg/day. Six-week treatment by vitamin E (400 mg/day) led to the significant increase of serum vitamin E (from 33.6+/-9.0 to 49.3+/-15.5 micromol/L) and to the significant decrease of MDA (from 2.62+/-0.5 to 2.36+/-0.4 micromol/L). The mean values of erythrocyte enzymes were in or under the lower margin of normal range and were not influenced by vitamin E in CAPD patients. The results of our study showed that orally administered vitamin E is a very important antioxidant agent for CAPD patients.

[Diagnosis and therapy of ethylene glycol poisoning--analysis of 20 patients]. / Diagnostika a liecba otravy etylénglykolom--rozbor 20 chorých.

The paper presents a retrospective analysis of 20 patients with acute ethylene glycol intoxication who were treated from 1972 to 2001 in the Dialysis Centre of the IVth Medical Clinic and from 1997 at the L. Pasteur Nephrological Clinic of the Faculty Hospital and Safarík Medical Faculty in Kosice. The ethylene glycol intoxication was manifested by neurological symptoms, extreme metabolic acidosis, acute toxic hepatitis and acute renal failure. Laboratory examination revealed oxaluria in 17 patients and leukocytosis in all patients. Percutaneous renal biopsy was made for differential diagnostic or forensic reasons in the convalescent stage of acute renal failure in 6 patients. In the treatment of ethylene glycol intoxication the authors used ethyl alcohol as an antidote: in the first four patients administered by the i.v. route, in the remaining patients in dialyzation solution. Extreme metabolic acidosis improved in 15 patients after bicarbonate haemodialysis. Concomitant application of haemoperfusion over active charcoal during the first haemodialysis in four patients led to a potentiated effect on the uraemic syndrome. Conservative and extracorporeal elimination treatment of ethylene glycol intoxication succeeded in 16 patients (80%). According to the authors' experience early and fractionated application of bicarbonate haemodialysis with 100 mg% concentration of ethylalcohol in the dialysis solution is the method of choice in the treatment of ethylene glycol intoxication.

A modified dialyzer with vitamin E and antioxidant defense parameters.

BACKGROUND: Oxidative stress, increased lipid peroxidation, and decreased activity of antioxidant systems may contribute to the accelerated development of atherosclerosis in patients receiving hemodialysis therapy for chronic renal failure. We investigated the influence of vitamin E on antioxidant defense parameters in hemodialysis patients who were using a modified dialyzer. METHODS: In eight hemodialyzed patients, erythrocyte antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPX), plasma total antioxidant capacity (TAC), the concentration of plasma malondialdehyde (MDA), and vitamins A, E, and C were investigated. Each parameter was measured before and after hemodialysis. The study was divided into three periods. Each period lasted three weeks, and during this time, 10 hemodialyses were performed. The first and second periods were carried out using the conventional dialyzer, Terumo CL-S15, but during the second period, patients received vitamin E 400 mg perorally after each hemodialysis. The third period was carried out using a modified dialyzer with vitamin E, Terumo CL-E15. All hemodialyzed patients were treated by erythropoietin and received vitamin C 50 mg/day and pyridoxine 20 mg/day during the entire study. RESULTS: The peroral administration of vitamin E led to a significant increase of serum vitamin E (22%), and no influence on other antioxidant defense parameters was found. The modified dialyzer with vitamin E led to a significant increase of serum vitamin E (33%) and TAC and to the significant decrease of plasma MDA. CONCLUSION: The results of our study suggest that the modified dialyzer with vitamin E provided more effective antioxidant defense than peroral administration of vitamin E in our hemodialysis patients.

Renal replacement therapy and secondary hyperoxalemia in chronic renal failure.

Oxalic acid is one of the well-known uremic toxins that participates in the pathogenesis of uremic syndrome. Secondary hyperoxalemia is a common feature in patients with chronic renal failure, but oxalate removal is not adequately accomplished by renal replacement therapy. In our series of patients, the plasma level of oxalic acid was significantly elevated, while the plasma vitamin C was in the normal range or in the upper margin of the normal range. The peritoneal clearance of oxalic acid was significantly lower in comparison to the peritoneal clearance of urea. Peritoneal clearance and peritoneal transfer of oxalic acid and other examined parameters increased using dialysis solution containing 2.5% glucose in comparison to dialysis solution containing 1.5% glucose. The significant hyperoxalemia of our patients persisted despite the relatively high peritoneal transfer of oxalic acid during continuous ambulatory peritoneal dialysis. The clearance of oxalic acid related to the clearance of urea was 58.1% during hemodialysis, 74.2% during postdilution hemofiltration, and 69.0% during postdilution hemodiafiltration. The sieving coefficient of oxalic acid during postdilution hemofiltration was 74.0% of urea sieving coefficient. The most significant decrease of plasma oxalic acid was observed during postdilution hemodiafiltation (63.3%). These results suggest that currently, renal replacement therapy is not effective enough for a permanent reduction of plasma oxalic acid.

[Oral administration of iron with vitamin C in haemodialyzed patients]. / Perorálne pouzitie zeleza s vitamínom C u hemodialyzovaných chorých.

One tablet of Sorbifer Durules contains 100 mg Fe2+ and 60 mg vitamin C. The authors examined in a short-term study 24 haemodialyzed patients with chronic renal failure of different etiology. The investigation was divided into three parts. During the first 4 weeks the patients did not receive Fe2+ nor vitamin C. During the subsequent four weeks the patients had Sorbifer Durules, one tablet/24 hours. This period was followed by another four weeks when the patients went again without Fe2+ and vitamin C treatment. At regular intervals, i.e. on days 0, 28, 56 and 84 the authors assessed the packed cell volume, blood haemoglobin and serum iron level, the total iron binding capacity, transferrin saturation, ferritin, and vitamin C in serum as well as the plasma oxalic acid level. Four weeks treatment using Sorbifer Durules led to a significant rise of the packed cell volume and haemoglobin in blood, iron and vitamin C in serum. This treatment did not affect the oxalic acid plasma level. Oral treatment with Sorbifer Durules, one tablet/24 hours, was adequate for maintaining the serum iron concentration in haemodialyzed patients during treatment with recombinant human erythropoietin. This treatment prevented at the same time the development of vitamin C deficiency in serum and a further rise of plasma oxalic acid in these patients.