Determination of As in tree-rings of poplar (Populus alba L.) by U-shaped DC arc.

An argon-stabilized U-shaped DC arc with a system for aerosol introduction was used for determination of As in poplar (Populus alba L.) tree-rings. After optimization of the operating parameters and selection of the most appropriate signal integration time (30 s), the limit of detection for As was reduced to 15.0 ng/mL. This detection limit obtained with the optimal integration time was compared with those for other methods: inductively coupled plasma-atomic emission spectrometry (ICP-AES), direct coupled plasma-atomic emission spectrometry (DCP-AES), microwave induced plasma-atomic emission spectrometry (MIP-AES) and improved thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS). Arsenic is toxic trace element which can adversely affect plant, animal and human health. As an indicator of environment pollution we collected poplar tree-rings from two locations. The first area was close to the "Nikola Tesla" (TENT-A) power plant, Obrenovac, while the other was in the urban area of Novi Sad. In all cases elevated average concentrations of As were registered in poplar tree-rings from the Obrenovac location.

[Use of mycophenolate mofetil in kidney transplantation]. / Primena mikofenolat mofetila kod transplantacije bubrega.

Mycophenolate mofetil (MMF) is a new immunosuppressive agent for the prevention of renal allograft rejection. MMF is a prodrug of mycophenolic acid (MPA), a fermentation product of several Penicillium species of fungus. MPA acts at a late stage in T and B lymphocyte proliferation by selective, uncompetitive and reversible inhibition of inosine monophosphate dehydrogenase, a key enzyme in the de novo pathway of purine nucleotide synthesis. The three large studies individually and the combined (pooled) 1-year patient efficacy data have shown that MMF, given in combination with cyclosporine and corticosteroids, significantly reduces the incidence of acute rejection episodes (by 50%), without detectable difference in patient mortality. Analysis of secondary efficacy endpoints revealed that patients treated with MMF required less additional immunosuppressive therapy for treatment of acute rejection episodes and showed better renal function. In another studies, the efficacy of MMF in the treatment of first acute rejection episodes and in the treatment of refractory, acute, cellular renal transplant rejections has been shown. The principal adverse events associated with MMF administration included diarrhea, vomiting, leukopenia and a higher frequency of certain types of infections. The efficacy of MMF for the treatment of chronic allograft nephropathy is controversial. The ability of MMF to reduce the occurrence of acute rejection episodes and improve allograft function may have significant implications for promoting the long-term survival of renal allografts, but we need long-term observations to prove this benefit.

[Replacement of mycophenolate mofetil with azathioprine in patients with renal transplants]. / Zamena mikofenolat mofetila azatioprinom kod bolesnika sa presadjenim bubregom.

Numerous clinical studies demonstrated that mycophenolate mofetil (MMF) was significantly more effective in prevention of acute rejection episodes than azathioprine. Since the data supporting the long-term benefits of MMF therapy are not available, and considering the high cost of this therapy, we examined the safety of conversion from MMF to azathioprine in renal transplant patients. In 12 renal transplant patients (4 cadaveric and 8 living related donors) on triple immunosuppressive therapy (prednisone/MMF/cyclosporine) conversion from MMF to azathioprine was done after the first six to twelve post-transplant months. The majority of patients were in the low immunological risk of transplantation, and 7 (58.3%) received antithymocite globulin due to the delayed graft function. The mean follow-up period after the conversion to azathioprine was 6.4 months (range 3-12 months). Acute rejection episode was noticed only in one patient 8 months after the conversion following acute graft pyelonephritis. In all other patients graft function remained unchanged. We have concluded that the conversion from MMF to azathioprine in renal transplant patients on triple immunosuppressive therapy is safe and without detrimental effects on short-term allograft function. Long-term follow-up studies on larger number of patients are needed to confirm these observations.

[Use of mycophenolate mofetil in patients with a transplanted kidney and cyclosporin nephrotoxicity]. / Primena mikofenolat mofetila kod bolesnika sa presadjenim bubregom i ciklosporinskom nefrotoksicnoscu.

Cyclosporine (CsA) nephrotoxicity is an important problem in renal transplant recipients, which can influence long-term graft survival. The safety of conversion from CsA to azathioprine (AZA) remains controversial and can result in higher incidence of acute rejection. Mycophenolate mofetil (MMF) is a new immunosuppressive agent superior to AZA in the prevention of acute rejection. Five patients with cyclosporine nephrotoxicity were converted from CsA/AZA/prednisolon to MMF/prednisolon protocol. All patients had low immunological risk and 4 out of 5 patients received antithymocyte globulin before conversion as the induction therapy or as the treatment for acute rejection. Mean follow-up after conversion was 16.8 months (range 4-32 months). No patient experienced acute rejection during follow-up period. The mean serum creatinine concentration decreased from 219 +/- 44.18 (range 168-280) to 122.6 +/- 48.02 mumol/l (range 72-187 mumol/l) (p = 0.002). Arterial hypertension improved after CsA withdrawal in 20% of patients. We have concluded that, in selected patients with cyclosporine nephrotoxicity, CsA withdrawal with concomitant use of MMF is safe and effective in the improvement of graft function and arterial hypertension.

[Outcome of kidney transplantation in patients on peritoneal dialysis]. / Ishod transplantacije bubrega kod bolesnika na peritoneumskoj dijalizi.

The initial experience suggested that kidney transplantation could be hazardous for patients on peritoneal dialysis due to the high risk of peritonitis and a possible high incidence of acute rejection. In this paper we have presented our experience with kidney transplantation in these patients. During the last four years kidney transplantation was performed in 9 patients on peritoneal dialysis. The average time spent on peritoneal dialysis was 20.6 +/- 7.6 months. In all patients peritoneal catheter was removed during the surgery. During the posttransplantation period a triple immunosuppressive therapy including steroids, cyclosporin and azathioprineor mycophenolate mofetil was administered in all patients. In comparison to patients on hemodialysis no significant difference in the incidence of acute rejection episodes, delayed graft function, graft arterial thrombosis and graft function recovery was observed. Patients on peritoneal dialysis had significantly greater and longer wound drainage in comparison to patients on hemodialysis. It was concluded that peritoneal dialysis had no negative influence on short-term outcome of kidney transplantation.

[Importance of determining the absolute CD3+ lymphocyte count during induction therapy with antithymocyte globulin in kidney transplantation patients]. / Znacaj odredjivanja apsolutnog broja CD3+ limfocita tokom indukcione terapije antitimocitnim globulinom kod bolesnika sa transplantovanim bubregom.

Antithymocyte globulin (ATG) is successfully applied in prophylaxis and treatment of renal allograft rejection. However, it is an expensive mode of therapy, associated with increased risk of opportunistic infections and lymphoproliferative diseases. For this reason, monitoring of ATG immunosuppressive effects as well as individual dose adjustment represent an important therapeutic approach. Here we report our results of ATG dose titration according to total lymphocyte count (< 300/microliter) and absolute CD3+ count (< 50/microliter) in seven renal transplant patients. Monitoring of absolute CD3+ count enabled reduction of the mean daily dose from the recommended dosage in all patients. Our results have also shown that the absolute CD3+ count is a more reliable parameter than the total lymphocyte count for monitoring of ATG biological effects on T cells. When rapid, significant and stable decrease of absolute CD3+ count is reached, ATG dose can be further adjusted according to the total lymphocyte count. With this approach, ATG treatment becomes rational and safe, with well established immunosuppressive effect, reduced risk of overimmunosuppression and considerable cost benefit.

[Tuberous sclerosis]. / Tuberozna skleroza.

Tuberous sclerosis is a rare hereditary disease which appears immediately after birth of during the second and third year of life. It is a multiorgan disorder characterized by convulsions, mental retardation and focal angiofibromyoma. The main findings are brain lesions including tuberous and astrocytes hamarthomas by which this disease was named. Renal alterations are angiofibromyolipoma and cysts, which are present in 40-80% of patients. The diagnosis is based on clinical, radiological and histological findings. This disease has a progressive course and fatal outcome. The therapy is symptomatic and surgical. The aim of this paper was to present this rare disease, which occurred in this patient during fourth year of life. Besides brain changes the patient also has extensive morphological renal alterations and renal failure. She died in 40th year of life due to multiorgan dysfunction.

[Analysis of a 4-year follow-up of the results of kidney transplantation from living related donors]. / Analiza cetvorogodiznjeg pracenja rezultata transplantacije bubrega od zivog srodnog davaoca.

The aim was to present a four-year experience in living related kidney transplantation. A total of 43 patients (9 females and 34 males) were enrolled in this study. The standard triple immunosuppressive therapy (steroids, azathioprine and cyclosporine) was administered in 19 (44.1%) patients, and in 20 (46.5%) mycophenolate mophetil in daily dose of 2 g instead of azathioprine. In 5 (14.2%) patients with high immunological risk and delayed graft function was administered antithymocite globulin in duration of 7-14 days, prophylactically. In 3 (6.97%) patients graft loss was caused by vascular complications and in 1 (2.32%) by infection as the complication. During the first post-transplantation year acute rejection was noticed in 8 (34.7%) patients and in 3 (37.5%) it was steroid resistant. The graft loss was never caused by acute rejection. Six-months graft survival was noticed in 91.1% patients and one-year graft survival in 88.4% patients. One-year patient survival was 100%. Short term results in living related kidney transplantation are excellent and nowadays, due to improvement in immunosuppressive therapy, the success in this type of kidney transplantation is mainly limited by surgical and infective complications.

[Hepatitis C virus infection in patients on chronic hemodialysis]. / Infekcija virusom hepatitisa C kod bolesnika na hronicnoj hemodijalizi.

Frequency of HCV infection was examined in patients on chronical program of hemodialysis considering the high risk to which they had been exposed because of frequent blood transfusion. We determined anti-HCV antibodies in 57 patients (29 male and 28 female) average age 52.6 years with terminal chronic renal failure. Frequency of anti-HCV antibodies (determined by ELISA Ortho test of first generation) was in correlation with the number of received transfusions and with duration of dialysis treatment and it was compared with anti-HCV antibody findings in hemodialysis staff (the control group of healthy persons). Results of the examination showed that anti HCV antibodies were positive in 38.95% examined patients (n = 57), and it showed that the patients on hemodialysis were a critical group for HCV infection. There was no correlation with the blood groups. Level of transaminases, HBsAg and immunity test in anti-HCV positive patients were in the physiological range. In order to prevent HCV infection in the dialysis centres, it is necessary to conduct routine test in patients and staff, and undertake all measures of protection.