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Publication
Featured researches published by Savas Ozturk.
Nephrology Dialysis Transplantation | 2008
Savas Ozturk; Dilek Guven Taymez; Gulistan Bahat; Reyhan Demirel; Halil Yazici; Nilgun Aysuna; Sule Sakar; Alaattin Yildiz
BACKGROUND Despite the developments in haemodialysis, there are still some difficulties in maintaining the haemodynamic stability. Bioimpedance analysis (BIA) has been proposed for the estimation of dry weight in haemodialysis patients. We aimed to investigate the effects of dialysate sodium and glucose contents on volume distribution in body compartments after haemodialysis by using BIA, a sensitive and reliable method. METHODS Seventeen chronic haemodialysis patients [11 males, 6 females, mean age: 36.9 (18-64) years] were included in the study. Patients were evaluated in three periods. The patients (period 1-P1) underwent haemodialysis with dialysate of 200 mg/dL glucose and 140 mmol/dL sodium for 4.5 h in the middle session of the first week. At the beginning and the end of the session, haematocrit, vital parameters (blood pressure, pulse), ultrafiltrated volume, plasma osmolarity and plasma renin activity were recorded. Also multi-frequency bioelectric impedance analyses (Bodystat Quadscan 4000) were applied to all patients at 5, 50, 100 and 200 kHz, including the impedance index (Z200/Z5). In the second midweek session the same procedure was repeated with same glucose concentration and 135 mmol/dL sodium including dialysate (period 2-P2), and in the third week, it was performed with a dialysate that included 140 mmol/dL sodium and no glucose (period 3-P3). RESULTS The change of the ratio of the intracellular volume to total body weight (ICV/TBW) at the beginning and the end of the session was same in all periods. However, there were significant differences in the change (after/before session) ratio for the extracellular volume/total body weight (ECV/TBW) in P2 compared to other periods (P values for P1-P2: <0.001 and P2-P3: 0.007). Likewise, the same was observed in the changes of impedance (P values for P1-P2: 0.08, P1-P3: 0.44 and P2-P3: 0.063). There was a significant increase of hypotensive events in P2 against the other periods (P = 0.001). CONCLUSION Decreasing dialysate sodium concentration results in important haemodynamic changes but the lack of glucose in dialysate does not result in any changes in haemodynamic and inflammatory parameters. The changes in bioimpedance parameters are parallel to haemodynamic changes in the haemodialysis patients.
Therapeutic Apheresis and Dialysis | 2011
Zeki Aydin; Meltem Gursu; Serhat Karadag; Sami Uzun; Emel Tatli; Abdullah Sumnu; Savas Ozturk; Rumeyza Kazancioglu
Anti‐neutrophilic cytoplasmic antibody (ANCA) positivity is seen in some systemic necrotizing vasculitides. Wegeners granulomatosis and microscopic polyangiitis are among the ANCA‐associated systemic vasculitides (AASV) and mortality is very high when renal failure occurs together with alveolar hemorrhage. The role of plasmapheresis in the treatment of these diseases has been studied retrospectively. Twelve patients with AASV who had plasmapheresis together with immunosuppressive medications have been involved. Primary diseases, immunosuppressive protocols, the number of plasmapheresis sessions, the amount of plasma that has been exchanged, urea and creatinine levels before and after treatment, pulmonary findings, the need for hemodialysis, and the outcome of patients were recorded. The mean age of patients was 52.9 ± 18.2 years. Wegeners granulomatosis was diagnosed in seven (58.3%) and microscopic polyangiitis in five (41.7%) patients. All patients had pulse cyclophosphamide and methylprednisolone followed by maintenance doses and plasmapheresis. Seven patients had hemodialysis at the beginning, and hemodialysis needed to be continued in three patients. Partial and complete remission was seen in 6 (50%) and 3 (25%) patients, respectively, and pulmonary findings regressed in all patients. End‐stage renal disease develops generally in AASV due to rapidly progressive glomerulonephritis causing severe irreversible glomerular damage. The mortality rate rises to 50% in cases of renal failure with diffuse alveolar hemorrhage; therefore, pulse immunosuppressive treatment with plasmapheresis may be life‐saving, as shown in our study.
Clinica Chimica Acta | 2010
Monica Dagnino; Gianluca Caridi; Zeki Aydin; Savas Ozturk; Zeynep Karaali; Rumeyza Kazancioglu; Kivanc Cefle; Meltem Gursu; Monica Campagnoli; Monica Galliano; Lorenzo Minchiotti
BACKGROUND Analbuminemia is a rare autosomal recessive disorder manifested by the absence, or severe reduction, of circulating serum albumin. The analbuminemic trait was diagnosed in a young Turkish woman on the basis of her clinical symptoms (bilateral lower limb edema) and biochemical findings (minimal albumin amount and variable increases in other protein fractions). METHODS Total DNA from the analbuminemic proband and her parents was PCR-amplified using oligonucleotide primers designed to amplify the 14 exons of the albumin gene (ALB) and the flanking intron regions. The products were screened for mutations by single-strand conformation polymorphism (SSCP) and heteroduplex analyses (HA). RESULTS HA allowed the identification of the mutation site in exon 12. Direct DNA sequencing of this abnormal fragment revealed that the analbuminemic trait was caused by a homozygous CA deletion at nucleotide positions c. 1614-1615 in the codons for Cys538 and Thr539. The subsequent frameshift should give rise to a putative truncated albumin variant in which the sequence Cys(538)-Thr-Leu-Ser has been changed to Cys(538)-Thr-Phe-Stop. The parents were heterozygous for the same mutation. CONCLUSIONS Gel-based mutation detection and DNA sequencing substantiate the clinical diagnosis of congenital analbuminemia in our patient and show that the condition is caused by a novel mutation within the ALB gene. These results contribute to shed light on the molecular basis of this rare condition.
Journal of Nephrology | 2012
Abdulbaki Kumbasar; Meltem Gursu; Cagdas Kaya; Savas Ozturk; Abdulkadir Ergen; Ahu Kemik; Zeki Aydin; Sami Uzun; Serhat Karadag; Rumeyza Kazancioglu
BACKGROUND Although intravenous iron (IVI) is thought to have potential inflammatory and atherogenic effects, there are not enough studies comparing these effects in chronic hemodialysis (HD) patients. In this study, different doses and types of IVI were examined for effects on inflammation and oxidative stress. METHODS Chronic HD patients (n=101) were grouped into those not receiving IVI (group 1, n=29), those getting intermittent iron sucrose (group 2, n=25), those receiving intermittent iron dextran (group 3, n=24) and those getting a once monthly total dose of iron dextran (group 4, n=23). Malondialdehyde (MDA), advanced oxidation protein product (AOPP), C-reactive protein (CRP) and TNF-α levels were measured on days 0, 2, 7 and 28. RESULTS Groups were similar regarding age, sex, hemoglobin, iron indices and total amount of IVI given monthly. Although MDA levels at days 7 and 28, AOPP levels at days 0 and 28, CRP levels at day 28 and TNF-α level at day 7 were higher than at other days, there were no significant differences between the IVI groups on statistical analysis. CONCLUSION The different types and doses (intermittent or once monthly total dose) of IVI treatments are well tolerated without negative effects on the markers of lipid and protein oxidation and inflammatory indices in chronic HD patients.
World journal of nephrology | 2015
Abdullah Sumnu; Meltem Gursu; Savas Ozturk
Primary glomerular diseases in the elderly population are a frustrating topic due to difficulties in both the diagnosis and decision making about treatment. The most frequent type of primary glomerular disease in elderly is membranous nephropathy; while its counterpart in younger population is IgA nephropathy. The most frequent cause of nephrotic syndrome in the elderly is also membranous nephropathy. Pauci-immune crescentic glomerulonephritis (GN) rate increases both in elderly and very elderly population. Pauci-immune crescentic GNs should be regarded as urgencies in elderly patients as in their younger counterparts due to potential for causing end-stage renal disease in case of delayed diagnosis and treatment, and also causing mortality due to alveolar hemorrhage in patients with pulmonary involvement. Renal biopsy is the inevitable diagnostic method in the elderly as in all other age groups. Renal biopsy prevents unnecessary treatments and provides prognostic data. So advanced age should not be the sole contraindication for renal biopsy. The course of primary glomerular diseases may differ in the elderly population. Acute kidney injury is more frequent in the course and renal functions may be worse at presentation. These patients are more prone to be hypertensive. The decision about adding immune suppressive therapies to conservative methods should be made considering many factors like co-morbidities, drug side effects and potential drug interactions, risk of infection, patient preference, life expectancy and renal functions at the time of diagnosis.
Renal Failure | 2007
Savas Ozturk; Dilek Arpaci; Halil Yazici; Dilek Guven Taymez; Nilgun Aysuna; Alaattin Yildiz; Mehmet Sukru Sever
The published studies on the prognosis of patients requiring intermittent hemodialysis (IHD) are scarce and have some conflicts. In this study, we retrospectively analyzed our data on ARF patients who were treated with IHD. A total of 192 (female: 85, 44.3%; male: 107, 55.7%) patients were included in the study. The mean age was 56.3 ± 17.1 years. In all, 48.9% of the patients were older than 60 years. The mean number of IHD sessions was 7.8 ± 8.0 per patient; 12.4% was due to prerenal causes, 76.8% was due to intrarenal causes, and 10.8% was due to postrenal causes. The leading indication of the IHD was uremic symptoms (46.8%). With the exclusion of hypertension, 72.4% of the patients had at least one systemic comorbidity. After treatment, 75.5% of the patients recovered, in contrast to 9.4% of patients who were transferred to chronic renal replacement programs and 15.1% who died during IHD period. Pre-dialytic serum creatinine (p = 0.003) and albumin levels (p = 0.016), total IHD session number per patient (p = 0.003), and age (p = 0.034) were the parameters that were related to high mortality in statistical analysis. Mortality was higher if the leading indication of IHD was biochemical disturbances (p = 0.013). Diabetes mellitus did not influence mortality. Consequently, predialytic serum creatinine and albumin levels may be very important predictors of mortality. Patients in high-risk groups (older age, female sex, and low pre-dialytic creatinine and albumin levels) should be considered to be treated with slow continuous renal replacement methods.
Clinical and Applied Thrombosis-Hemostasis | 2015
Hale Unal Aksu; Ender Oner; Omer Celik; Nilgun Isiksacan; Hüseyin Aksu; Sami Uzun; Derya Yavuz; Savas Ozturk; Mehmet Gül; Nevzat Uslu
The aim of this study was to evaluate the prevalence of aspirin resistance (AR) in patients undergoing hemodialysis (HD) and to assess the effect of HD on the results of the Multiplate test. A total of 54 patients undergoing HD were included in this study. Blood samples were taken just before and after the HD session. To determine AR, we used Multiplate test. Platelet aggregation values of the study population were 363.01 ± 225.69 aggregation unit (AU) × minutes before and 375.33 ± 254.05 AU × minutes after the HD (P = .597). There was strong correlation between the values before and after HD (R = .755, P < .0001). The AR status was changed in 9 (16.6%) patients after HD. Agreement of AR status before and after HD was substantial (κ coefficient = .667, P < .0001). The prevalence of AR in patients undergoing HD seems higher than in most of the studied populations, and this study has shown that the AR statuses of a significant number of patients undergoing HD change after an HD session.
Renal Failure | 2014
Zeki Aydin; Meltem Gursu; Serhat Karadag; Sami Uzun; Abdullah Sumnu; Yasemin Erdogan Doventas; Savas Ozturk; Rumeyza Kazancioglu
Abstract Introduction: Hepcidin, a small peptide hormone synthesized in the liver, plays central role in regulation of iron metabolism. Hepcidin generation in chronic kidney disease (CKD) is dependent on iron status, anemia, inflammation, and hypoxia and erythropoietin levels. In our study, the relationship between Prohepcidin levels and inflammation and iron indices in non-diabetic uremic patients was investigated. Methods: This study has a cross-sectional design which includes four groups: Non-diabetic 21 patients with stage 4 CKD (predialysis), 20 hemodialysis (HD) and 21 peritoneal dialysis (PD) patients and 17 healthy volunteers as the control group. Complete blood count, iron, total iron binding capacity (TIBC), ferritin, high-sensitive C-reactive protein (hsCRP), fibrinogen, parathyroid hormone, interleukin (IL)-6 and Prohepcidin levels were recorded. Results: Serum Prohepcidin levels in the predialysis, HD, PD and the control groups were 119.6 ± 45.1 ng/mL, 140.2 ± 41.8 ng/mL, 148.2 ± 35.0 ng/mL and 93.8 ± 21.9 ng/mL, respectively (p < 0.001). Prohepcidin was positively correlated with urea (r = 0.345, p = 0.002), creatinine (r = 0.465, p < 0.001), phosphorus (r = 0.253, p = 0.025), hsCRP (r = 0.275, p = 0.019), duration of dialysis treatment (r = 0.443, p < 0.001), fibrinogen (r = 0.467, p < 0.001) and IL-6 (r = 0.615, p < 0.001) levels. A negative correlation was detected between Prohepcidin levels and albumin (r = −0.286, p < 0.001), TIBC (r = −0.573, p < 0.001), GFR (r = −0.473, p < 0.001), hemoglobin (r = −0.351, p = 0.002) and hematocrit (r = −0.342, p = 0.002) levels. Discussion: Prohepcidin levels increase with deepening anemia and show positive correlation with inflammatory markers. Therapeutic interventions regarding Prohepcidin action on inflammatory status may play a role in the treatment of anemia due to inflammation. Functional iron deficiency is frequent in uremic patients. It may be beneficial to measure Prohepcidin level together with ferritin among these patients.
International Journal of Nephrology | 2012
Zeki Aydin; Meltem Gursu; Sami Uzun; Serhat Karadag; Emel Tatli; Abdullah Sumnu; Savas Ozturk; Rumeyza Kazancioglu
Aims. Vascular access is of prime importance for hemodialysis patients. We aimed to study early complications of hemodialysis catheters placed in different central veins in patients with acute or chronic renal failure with or without ultrasound (US ) guidance. Material and Methods. Patients who were admitted to our unit between March 2008 and December 2010 with need for vascular access have been included. 908 patients were examined for their demographic parameters, primary renal disease, and indication for catheterization, type and location of the catheter, implantation technique, and acute complications. Results. The mean age of the patients was 60.6 ± 16.0 years. 643 (70.8 %) of the catheters were temporary while 265 (29.2%) were permanent. 684 catheters were inserted to internal jugular veins, 213 to femoral, and 11 to subclavian veins. Arterial puncture occurred in 88 (9.7%) among which 13 had resultant subcutaneous hematoma. No patient had lung trauma and there had been no need for removal of the catheter or a surgical intervention for complications. US guidance in jugular vein and experience of operator decreased arterial puncture rate. Conclusion. US-guided replacement of catheter to internal jugular vein would decrease complication rate. Referral to invasive nephrologists may decrease use of subclavian vein. Experience improves complication rates even under US guidance.
Hemodialysis International | 2010
Rumeyza Kazancioglu; Savas Ozturk; Meltem Gursu; Umit Avsar; Zeki Aydin; Sami Uzun; Serhat Karadag; Emel Tatli; Fuat Sar
Clinical presentation of tuberculosis is different in hemodialysis patients than in the general population. This study aimed to analyze hemodialysis patients with tuberculosis in Istanbul. Patients who were on a chronic hemodialysis program in Istanbul for more than 3 months and diagnosed to have tuberculosis at least 3 months after the start of hemodialysis were included. To discard the effect of immigration from other cities, we included only patients who had started their dialysis program in Istanbul. Their demographic and clinical data were analyzed using Statistical Package for Social Sciences for Windows ver. 13.0. Of the 925 patients screened from 7 different centers, 31 (3.35%) were found to have tuberculosis. The mean age was 52.3±13.5 years. The male/female ratio was 18/13. The mean duration of dialysis therapy and the duration of dialysis till the diagnosis of tuberculosis were 62.6±54.3 and 21.7±25.7 months, respectively. Extrapulmonary tuberculosis constituted 48.39%. Treatment ended with a cure in 18 (58.05%); was still ongoing in 12 (38.70%) patients; and 1 (3.25%) died of pulmonary tuberculosis. The lower incidence of tuberculosis compared with previous reports may be related to the differences in the diagnostic criteria and the decrease in the rate of tuberculosis during recent years. The demographic and clinical parameters of the patients were quite similar to the average dialysis population in Turkey. Hence, we cannot address a subpopulation with additional risk. It is important to prevent tuberculosis in hemodialysis patients due to difficulties in the diagnosis and treatment. Thus we recommend routine screening of hemodialysis patients and effective isolation and treatment of infected patients.