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Y Erdem

Publications and source records attributed to Y Erdem.

At least 19 recordsLinked to original sources
PubMed2006

The role of proinflammatory cytokine gene polymorphisms for development of insulin resistance after renal transplantation.

BACKGROUND: Insulin resistance, a frequent prediabetic metabolic complication after renal transplantation, is generally linked to immunosuppressive drugs including corticosteroids, cyclosporine (CsA) or tacrolimus, as well as to age, cadaveric donors and ethnic factors. Cytokines are known to be inflammation modulatory substances that contribute to metabolic derangements after transplantation. The present study investigated the effects of cytokine gene polymorphisms on insulin resistance in renal transplant recipients. PATIENTS AND METHODS: Sixty-one renal transplant recipients (37 men, 24 women; mean age: 39.3 +/- 10.8 years) who attended regular clinical visits without a known history of diabetes were enrolled in the study. All patients were on a regimen of steroid, CsA, and mycophenolate mofetil. Venous blood samples were collected for biochemical analyses after an overnight fast at 08:00 pm. CsA trough levels, C-reactive protein, and fibrinogen were also estimated. Additional 10 mL of blood was withdrawn into an ethylenediamine tetraacetic acid-containing tube to determine cytokine genotypes (tumor necrosis factor-alpha [TNF-alpha] -238 G/A, transforming growth factor-beta [TGF-beta] codon 10 -869 T/C). Insulin resistance was calculated by the homeostasis model assessment (HOMA) method using the values of fasting blood glucose (FBG) and insulin levels. Anthropometric indices as well as body height, weight, waist and hip circumferences were measured simultaneously to calculate body mass index (kg/m2) and waist-to-hip ratio. Impaired fasting glucose (IFG) was described as an FBG > or = 110 but < 126 mg/dL. RESULTS: IFG was detected in 27.9% of this study group. The HOMA index was significantly higher among patients with IFG compared with normal FBG (NoGT) (6.3 +/- 4.5 vs 3.7 +/- 1.5; P = .01). Neither FBG and insulin nor HOMA values correlated with antrophometric, metabolic, or inflammatory parameters. Cytokine genotype allele frequencies, age, sex, immunosuppressive and antihypertensive drug type and doses, CsA trough levels, and donor source (cadaveric/living) were similar for patients with IFG and NoGT. Mutant allele carrier genotypes (AA + GA) for TNF-alpha -238 G/A showed higher fasting insulin (14.0 +/- 7.9 vs 34.1 +/- 17.7 microIU/mL; P = .04) and HOMA (4.01 +/- 2.01 vs 7.95 +/- 5.44; P = .002) levels than GG homozygote subjects. FBG, HOMA, and other metabolic and anthropometric indices were similar between TGF-beta codon 10 -869 T/C genotypes. The daily dose of steroid (mg/d) and A allele frequency for TNF-alpha -238 G/A genotype were significant predictors of HOMA index in linear regression analysis. CONCLUSION: The present study revealed that beside the daily dose of steroids, TNF-alpha -238 G/A genotype may contribute to insulin resistance in renal transplant recipients. Further investigations may highlight the effects of cytokine gene heterogenity on insulin resistance in those patients.

Adult↗
PubMed2004

Prediction of renal allograft function with early Doppler ultrasonography.

INTRODUCTION: Doppler ultrasonography (USG) is an useful, noninvasive diagnostic tool for the management and follow-up of the transplanted kidney. However, it is believed that the value of Doppler USG is limited to discrimination of acute rejection episodes. We tested whether early Doppler USG findings were predictive of 1-month and 1-year allograft functions in noncomplicated renal transplant recipients (RTRs). PATIENTS AND METHODS: Resistive index (RI) and pulsatile index (PI) values obtained by doppler USG within the first week of transplantation were correlated with allograft function at 1 month and 1 year in 45 (10 women, 35 men, mean age: 27 years) noncomplicated cases. Patients with complications during the first posttransplant year were not included. RESULTS: There was a negative correlation between both RI and PI with creatinine clearance values at 1 month and at 1 year posttransplant. There was a significant decline in allograft function among cases with either RI > or = 0.7 or PI > or = 1.1. Patients with impaired allograft function have higher RI and PI values. CONCLUSION: Renal allograft survival is influenced by many factors. However, no reliable simple parameter has been identified to predict long-term outcome. Doppler USG performed during the early transplantation period with calculation of RI and PI may have a predictive value to forecast early and long-term outcomes of noncomplicated kidney transplants.

Adult↗
PubMed2002

Pure red cell aplasia preceding malignant lymphoma in a renal transplant patient.

Malignant disorders are one of the major causes of morbidity and mortality in transplant patients. We present herein a renal transplant recipient with malignant lymphoma which preceded by pure red cell aplasia (PRCA). Acquired PRCA is a rare hematologic disorder in renal transplant recipients. It has been associated with a variety of disorders of immunologic dysfunction and neoplasms, exposure to drugs and toxins, infectious diseases, pregnancy and severe nutritional deficiency. This is the first case with PRCA preceding the malign lymphoma in a renal transplant patient. Treatment of lymphoma and lymphoma-related humoral and cellular changes or other undefined effects that may be related to therapy may be responsible of the resolving of PRCA in this patient. In this regard, renal transplant patients with acquired PRCA, must be closely followed for an underlying neoplastic disorder.

Disease Progression↗
PubMed2000

Bone mineral density in haemodialysis patients: A comparative study of dual-energy X-ray absorptiometry and quantitative ultrasound.

BACKGROUND: Quantitative ultrasound (QUS) of bone is a relatively new technique that appears to assess 'bone quality' in addition to bone mineral density. The purpose of this study was to evaluate the diagnostic potential of QUS of calcaneum and to correlate it with dual energy X-ray absorptiometry (DEXA) in chronic haemodialysis patients. METHODS: Broad-band ultrasound attenuation (BUA; dB/MHz) and speed of sound (SOS; m/s) of calcaneum and DEXA (g/cm(2)) measurements of the lumbar spine and hip were made in 39 patients. The indices obtained by either method were compared with age-and sex-matched controls. Calcaneal measurements were correlated to DEXA and relevant clinical and biochemical data of patients. RESULTS: BUA and SOS values were markedly reduced in dialysis patients compared to controls (59.1+/-13.8 vs 73.0+/-16.2 dB/MHz, P:<0.001 and 1533+/-28 vs 1560+/-29 m/s, P:=0.014 respectively). There was a moderate, but significant association between calcaneal parameters and DEXA (r=0.32-0.53, P:<0.05). Both BUA and SOS scores were inversely correlated with age (r=-0.69, P:<0.001) and duration of menopause (r=-0.74, P:<0.01). Additionally, BUA values showed a moderate negative association with serum intact parathyroid values (r=-0.38, P:=0.018). CONCLUSION: Chronic haemodialysis patients have reduced calcaneal BUA and SOS scores. QUS of the calcaneum is an easy-to-apply and radiation-free technique. It could be a useful substitute for assessment of bone density in such patients. However, further studies in large patient groups and comparisons with plasma markers of bone turnover and bone biopsy findings are needed to assess its potential place in the management of renal osteodystrophy.

Absorptiometry, Photon↗
PubMed2000

Tc-99m DTPA acetylsalicylic acid (aspirin) renography in the detection of renovascular hypertension.

PURPOSE: Prostaglandins play important roles in renal physiology and in the development of renovascular hypertension. In a recent study, inhibition of renal prostaglandin synthesis was found to be useful for detecting renovascular hypertension using renal scintigraphy. In the current study, the authors evaluated the role of aspirin (an inhibitor of prostaglandin synthesis) and compared it with Tc-99m DTPA captopril renal scintigraphy (CS). MATERIALS AND METHODS: Twenty-five patients were examined with Tc-99m DTPA in a three-step manner: a baseline study, CS, and aspirin scintigraphy (AS). Each scintigraphic study was interpreted visually and according to the renogram curve patterns. Semiquantitative parameters (Tmax, renal indices [%], 20-minute/max count ratio, glomerular filtration rate) were also calculated. Plasma renin activity was determined for each study. The blood pressures of all patients were measured during AS. All patients had a contrast-enhanced angiogram that was used as the reference test. RESULTS: Three groups of patients were observed based on the scintigraphic and angiographic results. In each group, no difference was observed in blood pressure after aspirin administration. In group 1, seven patients had normal angiographic and scintigraphic results. In group 2, eight patients had angiographically confirmed renal artery stenosis (RAS). In 6 patients (mean, 47% RAS), both AS and CS were negative for RVH. In the remaining two patients with RAS (mean, 83% stenosis), the kidneys were atrophic on the stenotic side, and thus the kidneys did not respond to the interventions. No difference was observed in plasma renin activity in groups 1 and 2. Group 3 included 10 patients who had angiographically confirmed RAS (mean, 86%). In 9 patients, both CS and AS were positive for RVH. In the remaining one patient, scintigraphic results were falsely negative. Statistical analyses performed for semiquantitative parameters did not reveal any significant difference in this group, although there was a tendency toward prolonged Tmax values after captopril and aspirin administration. In four cases, unexpected elevation of plasma renin activity was observed in group 3. CONCLUSIONS: These data indicate that AS with Tc-99m DTPA is an alternative for CS. It has the advantage of having no effect on blood pressure and does not require that angiotensin-converting enzyme inhibitors be discontinued. Although in this study 9 of 10 patients had correct diagnoses of RAS, further studies, especially using tubular agents with the calculation of parenchymal transit time, might provide valuable information in this patient group. An ongoing study is being performed in the authors' institute.

Adolescent↗
PubMed1999

Effects of angiotensin converting enzyme and angiotensin II receptor inhibition on impaired fibrinolysis in systemic hypertension.

Abnormalities in fibrinolysis have been reported in hypertension. Angiotensin converting enzyme (ACE) inhibitors have been shown to improve altered fibrinolytic balance in hypertensive patients. It has not been documented, however, whether this is due to a decrease in angiotensin II (Ang-II) generation or is a consequence of elevated local levels of bradykinin. Accordingly, the aim of this study was to determine the effects of an ACE inhibitor (perindopril) and an Ang-II receptor antagonist (losartan) on fibrinolytic kinetics. We have examined the serum levels of the plasminogen activator inhibitor type-1 (PAI-1) antigen and activity, tissue plasminogen activator (t-PA) antigen and activity, soluble thrombomodulin (sTM), and tissue factor pathway inhibitor (TFPI) before and after reaching the target blood pressure (<140/90 mm Hg) in 13 hypertensive patients receiving perindopril (mean age 40+/-11 years, 6 women, 7 men) and in 12 patients receiving losartan (mean age 38+/-9 years, 6 women, 6 men). We also compared the baseline fibrinolytic activity of hypertensive patients with that of 12 normotensive control persons (mean age 40+/-9 years, 6 women, 6 men). The mean basal plasma levels of PAI-1 antigen, PAI-1 activity, and sTM were significantly higher in the hypertensive patients than in normal controls (P<.005). The values of other analytes were similar in both groups. Increased plasma levels of PAI-1 antigen, PAI-1 activity, and sTM were reduced in patients after they were given perindopril and losartan (P<.005); the reductions in losartan-receiving group were more pronounced (P<.05). There were no significant effects on the plasma levels of t-PA antigen, t-PA activity, and TFPI in patients receiving the two therapeutic regimens (P>.05). In conclusion, chronic hypertension is associated with hypofibrinolysis. The beneficial effect of ACE inhibitors on fibrinolysis seems to be related to the blockade of Ang-II, and increased kinin activity does not appear to play a major role.

Adolescent↗
PubMed1999

Protein Z levels in haemodialysis patients.

Protein Z (PZ) is a vitamin K-dependent protein isolated from human and bovine plasmas. Although the exact role of PZ in the haemostatic system is presently unknown, it is suggested that PZ deficiency may cause bleeding tendency. Haemostatic alterations in end-stage renal failure (ESRF) are certainly complex and involve several abnormalities in the coagulation and fibrinolytic system. In order to elucidate the detail of the haemostasis in ESRF, we aimed to investigate PZ activity in haemodialysis patients. Therefore, we compared plasma PZ levels in 10 haemodialysis patients (6 M, 4 F, mean age 36+/-11) and 10 healthy normal controls (5 M, 5 F, mean age 34+/-8) in this study. We found mean plasma PZ levels in haemodialysis patients and healthy controls 6.95+/-2.93 microg/ml and 3.06+/-0.81 microg/ml, respectively (p<0.005). Increased level of PZ which influences the action of thrombin on its protein substrates and inhibitors may contribute to the haemostatis alterations in ESRF patients, in addition to other well known abnormalities in the coagulation and fibrinolytic system.

Adult↗
PubMed1999

Serum thrombopoietin levels in haemodialysis patients: involvement of arteriovenous fistula.

BACKGROUND: Thrombopoietin (Tpo) is a recently cloned growth factor which plays a critical role in the regulation of thrombopoiesis. Tpo has also been shown to stimulate in vitro and in vivo erythroid cell growth. Although Tpo transcripts were detected in hepatocytes, proximal tubules and endothelium, mechanisms regulating the level of circulating Tpo have not been fully delineated. Changes in the vessel wall and blood flow in arteriovenous fistula (AVF) might alter Tpo activity. METHODS: Serum thrombopoietin levels and serum erythropoietin levels in samples concurrently obtained from venous returns of AVF and contralateral peripheral veins in 31 haemodialysis patients were determined and compared with 12 healthy controls. Levels were also compared between 14 haemodialysis patients (group I) treated with recombinant human erythropoietin (rHu-Epo) and 17 haemodialysis patients (group II) not requiring rHu-Epo. RESULTS: Serum Tpo levels (44.8 +/- 23.9 pg/ml, vs 129.9 +/- 113.6 pg/ml, P<0.05) and platelet counts (194 +/- 55, 10(6)/ml vs 273 +/- 94. 10(6)/ml, P<0.05) of haemodialysis patients were lower than healthy controls. Serum Tpo levels were inversely correlated with platelet counts in the control group (R=-0.61, P<0.05), but not in haemodialysis patients. Tpo concentrations of AVF samples were lower than peripheral venous samples (31.6 +/- 17.7 pg/ml vs 44.8 +/- 23.9 pg/ml, P=0.001). No significant difference was present between the serum Tpo concentrations of haemodialysis patients in group I and group II. Serum Tpo levels were not correlated with haemoglobin levels or serum erythropoietin levels in haemodialysis patients. CONCLUSION: Decreased serum Tpo levels despite low platelet counts in haemodialysis patients suggest that the proposed feedback mechanism of platelet uptake of Tpo is not fully operative in these patients. Moreover, AVF might affect the local production and/or catabolism of this growth factor.

Adolescent↗
PubMed1999

Thrombopoietin and thrombospondin in renal allograft recipients.

Recipients of renal transplants appear to be at increased risk of thromboembolic events. Despite accumulating evidence for the hyperreactivity of platelets, the primary regulator of thrombopoiesis, thrombopoietin (TPO), has not yet been studied in renal transplant recipients. Thus, the aim of the present study was to quantify the levels of TPO and to assess its contribution to increased platelet reactivity in recipients of renal allografts. Serum concentrations of thrombospondin (TSP) were also determined in patients undergoing renal transplants in order to evaluate the role of this multifunctional protein in platelet hyperaggregability. Serum levels of TPO were significantly lower in renal transplant recipients (n = 27) than in healthy controls (30.8+/-20.6 pg/ml versus 129.9+/-113.6 pg/ml, P = 0.001). Serum concentrations of TPO were correlated neither with serum levels of creatinine nor duration of transplantation. However, levels of TPO were negatively correlated with platelet counts (r = -0.50, P = 0.007) in recipients of renal transplants. Plasma levels of TSP were higher in renal transplant patients than in the control group (104.5+/-54.7 ng/ml versus 63.4+/-41.5 ng/ml, P = 0.003). No significant correlation was found between levels of TPO and TSP. We conclude that, rather than the allograft function, the platelet mass determines the levels of TPO in recipients of renal transplants. Despite the low serum levels of TPO, and increased concentrations of TSP, TPO might still play a role in the hyperaggregability of platelets in patients undergoing renal transplants.

Adult↗
PubMed1999

Cyclical acute renal failure due to bilateral ureteral endometriosis.

Endometriosis is a common disease but ureteral involvement is relatively rare. Ureteric endometriosis is mostly unilateral. Endometriotic ureteral obstruction is a serious event commonly diagnosed late and therefore associated with a major risk of hydronephrotic renal atrophy. We present the cyclical acute renal failure associated with menstruation in a patient who developed severe bilateral ureteral obstruction due to endometriosis. Physicians should be aware of this uncommon but serious manifestation of endometriosis, especially if the clinical presentation is cyclical acute renal dysfunction in a premenopausal woman.

Acute Kidney Injury↗
PubMed1999

Determinants of soluble CD23 antigen levels in hemodialysis patients: effect of 1.25 dihydroxyvitamin D3 and recombinant human erythropoietin treatment.

BACKGROUND: The immunodeficiency of end-stage renal disease (ESRD) paradoxically coexists with T cell and monocyte activation. In spite of well known defective antibody responses in ESRD, the functional status of B cells in the immune system dysregulation of uremia is still controversial. Soluble CD23 (sCD23) antigen is a recently identified B cell activation marker and is also involved in T cell activation process. Effects of parathyroid hormone (PTH), red blood cells and ferritin on T and B cell functions have been shown both in vivo and in vitro. PATIENTS AND METHODS: In this study, serum levels of sCD23 in hemodialysis patients were determined to evaluate the functional status of B cells and possible linkages between this cytokine and PTH levels, ferritin levels, red blood cell counts were investigated. RESULTS: Serum sCD23 levels were significantly elevated in hemodialysis patients relative to healthy controls (12.5+/-8.4 micro/l vs. 2.4+/-1.1 micro/l, p<0.001). Serum sCD23 levels were negatively correlated with red blood cell count (r = -0.61, p = 0.009) and serum PTH levels (r = -0.62, p = 0.008), while positively correlated with serum ferritin levels (r = 0.63, p = 0.007) in hemodialysis patients. We also investigated the immunumodulator effects of 1.25 dihydroxyvitamin D3 (1.25OHD3) and recombinant human erythropoietin (rHu-Epo) treatment in hemodialysis patients. 1.25OHD3 treatment for eight weeks did not change serum sCD23 levels in hemodialysis patients (n = 8). On the other side, rHu-Epo administration for 16 weeks led to a decrease in serum sCD23 levels (17.7+/-8.6 microg/l vs. 9.8+/-3.5 microg/l, p = 0.007) in these patients (n = 9). CONCLUSION: These results suggests that similar to T cells, B cells are activated in uremia and the degree of this activation is correlated with red blood cell count, serum parathyroid hormone levels and iron status of the hemodialysis patients. Moreover, B cell activation could be altered by recombinant human erythropoietin therapy in hemodialysis patients.

Adult↗
PubMed1998

Reliability of a hospital utilization review method in Turkey.

OBJECTIVE: To determine whether the Appropriateness Evaluation Protocol (AEP) is reliable in Turkey. METHODS: Three reviewers, two physicians and one nurse each reviewed 196 patient-days concurrently by using the AEP at three hospitals, two of which were teaching hospitals. Inter-reviewer reliability was assessed both for all cases reviewed (overall agreement), and for only those judged inappropriate by at least one reviewer (specific agreement). In addition, overall agreement between pairs of reviewers was evaluated by the Kappa statistic. RESULTS: The overall agreement between pairs of reviewers was very high: 93.4-95.9%, and it was similar between all pairs. The level of overall agreement was highly statistically significant: k=0.725-0.833, P<0.001. The specific agreement rates ranged from a low of 61.8% to a high of 75%. CONCLUSIONS: These results show, for the first time, that the AEP method is reliable in Turkey.

Hospitals, Teaching↗
PubMed1998

Effect of enalapril on exaggerated erythropoietin response to phlebotomy in erythrocytosic renal transplant patients.

BACKGROUND: Exaggerated erythropoietin (EPO) response to phlebotomy regardless of the baseline EPO levels have been shown in patients with post-transplant erythrocytosis (PTE) and administration of angiotensin-converting enzyme inhibitors (ACE-1) seems to be effective in controlling PTE. However, the mechanism of this ACE-1 induced reduction in haematocrit (Hct) is not well known. Although some authors have suggested that ACE-1 may reduce EPO secretion, this is still controversial. The aim of the present study was to assess the effect of a single dose ACE-1 on exaggerated EPO response to phlebotomy. METHODS: In this study, we compared serum EPO and renin (PRA) levels of 10 PTE patients, 10 non-PTE patients and 10 healthy blood donors before and after phlebotomy. The effects of a single dose of ACE-1 (enalapril, 5 mg p.o.) in PTE patients were also evaluated in the second phlebotomy. RESULTS: While the mean basal serum EPO level was significantly higher in the PTE group than the other two groups (P<0.01), the mean basal PRA levels did not differ significantly between these groups. Serum EPO and PRA levels increased significantly after the phlebotomy (P<0.001) and exaggerated EPO response to phlebotomy was suppressed by single dose enalapril (P<0.001) in the PTE patients. CONCLUSION: The present study has shown that the renin angiotensin system plays an important role in EPO formation and the Hct lowering effect of the ACE-1 is through reduction of EPO in PTE patients.

Adult↗