Biomedical subjects

Mehmet S Sever

Publications and source records attributed to Mehmet S Sever.

8 recordsLinked to original sources

PubMed2006

Changes in endothelial function before and after renal transplantation.

Endothelial dysfunction is an early key event in the development of atherosclerotic cardiovascular disease observed in chronic renal failure patients. The role of renal transplantation (RTx) on endothelial dysfunction is still unclear. The aim of this study was to evaluate the endothelial function of chronic renal failure patients before RTx (while they were on hemodialysis, HD), and after RTx (at the 6th and 12th months) by a noninvasive method, brachial arterial ultrasound. A total of 22 (17 male, mean age: 33.9 +/- 11.6 years) RTx recipients were enrolled in the study. Endothelium-dependent vasodilation (EDD) was assessed by establishing reactive hyperemia. EDD prior to transplantation was significantly lower when compared with EDD measured at the 6th and 12th months after RTx (EDD pretransplantation: 6 +/- 3.7%, EDD at the 6th month of RTx: 8.3 +/- 2.3% and EDD at the 12th month of RTx: 12.1 +/- 3.6%, P < 0.001). When the EDD values measured at the 6th and 12th months of RTx were compared, measurements of the 12th month were found significantly higher than those of the 6th month (P < 0.001). Our results also showed that RTx has provided improvement in endothelial function by eliminating the uremic environment although not in the early post-RTx period.

Adolescent↗

PubMed2004

Early and vigorous fluid resuscitation prevents acute renal failure in the crush victims of catastrophic earthquakes.

This study analyzes the effects of fluid resuscitation in the crush victims of the Bingol earthquake, which occurred in May 2003 in southeastern Turkey. Questionnaires asking about demographic, clinical, laboratory, and therapeutic features of 16 crush victims were filled in retrospectively. Mean duration under the rubble was 10.3 +/- 7 h, and all patients had severe rhabdomyolysis. Fourteen patients were receiving isotonic saline at admission, which was followed by mannitol-alkaline fluid resuscitation. All but two patients were polyuric. Admission serum creatinine level was lower than and higher than 1.5 mg/dl in 11 and 5 patients, respectively. Marked elevations were noted in muscle enzymes in all patients. During the clinical course, hypokalemia was observed in nine patients, all of whom needed energetic potassium chloride replacement. Four (25%) of 16 victims required hemodialysis. Duration between rescue and initiation of fluids was significantly longer in the dialyzed victims as compared with nondialyzed ones (9.3 +/- 1.7 versus 3.7 +/- 3.3 h, P < 0.03). Sixteen fasciotomies were performed in 11 patients (68%), nine of which were complicated by wound infections. All patients survived and were discharged from the hospital with good renal function. Early and vigorous fluid resuscitation followed by mannitol-alkaline diuresis prevents acute renal failure in crush victims, resulting in a more favorable outcome.

Acute Kidney Injury↗

PubMed2003

The effect of calcineurin inhibitors on endothelial function in renal transplant recipients.

Endothelial dysfunction is of vital importance, as it may cause ischemia and dysfunction in various organs. Despite, this problem has been well documented in patients with end-stage renal disease (ESRD), there is not enough data considering this issue following renal transplantation. One of the potential causes of endothelial dysfunction in renal transplant recipients may be administration of calcineurin inhibitors. The aim of this study is to evaluate the effects of two different calcineurin inhibitors [cyclosporin A (CsA) and tacrolimus (FK506)] on endothelial function in renal transplant patients. Forty-four renal transplant recipients [22 on FK506 (group I) and 22 on CsA (group II)] were studied. Endothelial functions of the brachial artery were evaluated by using high resolution vascular ultrasound. Endothelium-dependent and -independent vasodilations were assessed by establishing reactive hyperemia and using sublingual nitroglycerine (NTG), respectively. Results are presented as percentage change from baseline values. Significant endothelial dysfunction was noted in renal transplant patients treated with CsA. While endothelium-dependent vasodilation was 12.1 +/- 5.1% in group I and it was 6.5 +/- 3.7% in group II (p < 0.001). The increase in brachial artery diameter after sublingual NTG was 20.1 +/- 6.3 and 12.7 +/- 5.6% in groups I and II, respectively. This indicates that the endothelium-dependent and -independent vasodilation of the patients on FK506 is better preserved than the patients on CsA therapy. Besides, blood flow volume (BFV) increase was 51.2 +/- 39.4 and 43.9 +/- 24.3%, in groups I and II, respectively, in reactive hyperemia period (p > 0.05). Post-transplant course of renal transplant recipients is complicated by endothelial dysfunction. This problem is more prominent in patients on CsA therapy, which can predispose these patients to more frequent cardiac complications.

Adult↗

PubMed2003

Endothelial function is more impaired in hemodialysis patients than renal transplant recipients.

BACKGROUND: Endothelial dysfunction (ED) is a common precursor and denominator of cardiovascular events including development of atherosclerosis. In this cross-sectional, controlled study, we aimed to investigate ED measured by ischemia-induced forearm vasodilatation in chronic hemodialysis (HD) patients and renal transplant recipients (rTX). PATIENTS AND METHODS: Thirty-nine HD patients, 39 rTX and 38 normotensive healthy controls were included. There was no difference in age and gender distribution among the study groups. The mean time spent on dialysis and transplantation were 74 +/- 46 and 68 +/- 39 months. Serum high sensitive C-reactive protein (hs-CRP) and plasma fibrinogen levels were measured. Endothelium dependent post-ischemic vasodilatation of brachial artery was used to evaluate ED. RESULTS: The hs-CRP and plasma fibrinogen levels were significantly increased in HD patients when compared with rTX. On high resolution ultrasonographic examination, post-ischemic vasodilatation values in HD patients (9.55 +/- 6.47%) were significantly lower than rTX (14.39 +/- 8.06%, p = 0.007) and controls (20.42 +/- 6.10%, p < 0.001). Renal transplant recipients also had significantly lower post-ischemic vasodilatation values than controls (p = 0.001). The hs-CRP levels were negatively correlated with endothelium-dependent dilatations in TX (r = -0.59, p = 0.001), however, this correlation was not detected in HDp. CONCLUSION: Patients with end-stage renal disease have ED. Endothelial function is more impaired in HD patients than rTX. Different mechanisms might be responsible for ED in HD patients and rTX.

Adult↗

PubMed2003

Left ventricular hypertrophy and endothelial dysfunction in chronic hemodialysis patients.

BACKGROUND: Endothelial dysfunction (ED), which is a risk factor for atherosclerosis, has been reported recently in chronic hemodialysis (CHD) patients. In this study, we aim to investigate the association of ED and presence of left ventricular hypertrophy (LVH) in CHD patients. METHODS: One hundred four CHD patients (47 men, 57 women; mean age, 45 +/- 12 years) and 49 age- and sex-matched controls were included. Mean time on dialysis therapy was 62 months. Echocardiographic examination and flow-mediated endothelium-dependent (EDD) and endothelium-independent dilatation (EID) of the brachial artery, measured by high-resolution ultrasonography, a noninvasive method for assessing endothelial function, were performed on a nondialysis day. RESULTS: LVH was detected in 72 CHD patients (69%). Patients with LVH had a lower EDD (9.3% +/- 6.1% versus 12.1% +/- 8.3%; P = 0.06), but the difference was not significant. Mean EID was significantly lower in CHD patients with LVH (13.6% +/- 7.6% versus 18.6% +/- 9.8%; P = 0.008). Left ventricular mass index (LVMI) correlated with both EDD (r = -0.22; P = 0.03) and EID (r = -0.32; P = 0.002). Patients with LVH had a greater rate of hypertension (35 of 72 versus 7 of 32 patients; P = 0.02) and lower hemoglobin levels (11.0 +/- 1.8 versus 11.8 +/- 1.6 g/dL [110 +/- 18 versus 118 +/- 16 g/L]; P = 0.05). CHD patients had a lower EDD (10.2% +/- 6.9% versus 20.9% +/- 7.6%; P < 0.001) and EID (15.0% +/- 8.5% versus 27.8% +/- 8.5%; P < 0.001) compared with controls. In linear regression analysis for predicting LVMI, presence of hypertension, hemoglobin level, and EID, but not EDD, were found to be independent variables. CONCLUSION: EID, which may reflect decreased elasticity of arteries, contributes to the development of LVH in CHD patients, in addition to hypertension and anemia.

Adolescent↗

PubMed2002

Renal replacement therapies in the aftermath of the catastrophic Marmara earthquake.

BACKGROUND: Renal replacement therapy is of vital importance in the treatment of crush syndrome victims, who are frequently encountered after catastrophic earthquakes. The Marmara earthquake, which struck Northwestern Turkey in August 1999, was characterized by 477 victims who needed dialysis. METHOD: Within the first week of the disaster, questionnaires containing 63 clinical and laboratory variables were sent to 35 reference hospitals that treated the victims. Information considering the features of dialyses obtained through these questionnaires was submitted to analysis. RESULTS: Overall, 639 casualties with renal complications were registered, 477 of whom (mean age 32.3 +/- 13.7 years, 269 male) needed dialysis. Among these, 452 were treated by a single dialysis modality (437 intermittent hemodialysis, 11 continuous renal replacement therapy and 4 peritoneal dialysis), while 25 victims needed more than one type of dialysis. In total, 5137 hemodialysis sessions were performed (mean 11.1 +/- 8.0 sessions per patient) and mean duration of hemodialysis support was 13.4 +/- 9.0 days; this duration was shorter in the non-survivors (7.0 +/- 8.7 vs. 10.0 +/- 9.8 days, P = 0.005). Thirty-four victims who underwent continuous renal replacement therapy had higher mortality rates (41.2 vs. 13.7%, P < 0.0001). Only eight victims were treated by peritoneal dialysis, four of whom also required hemodialysis or continuous renal replacement therapy. The mortality rate in the dialyzed victims was 17.2%, a significantly higher figure compared to the mortality rate of the non-dialyzed patients with renal problems (9.3%; P = 0.015). CONCLUSION: Substantial amounts of dialysis support may be necessary for treating the victims of mass disasters complicated with crush syndrome. Dialyzed patients are characterized by higher rates of morbidity and mortality.

Acute Kidney Injury↗

PubMedDate not supplied

Effect of gender on various parameters of crush syndrome victims of the Marmara earthquake.

BACKGROUND: Detailed analyses on crush syndrome resulting from earthquakes is scarce. This study aimed to analyze the effect of gender on clinical course of the renal victims of the catastrophic Marmara earthquake that struck Northwestern Turkey in 1999. METHODS: Questionnaires were prepared within the first week of disaster and sent to 35 reference hospitals that treated the victims. Relationship between gender and various epidemiological, clinical, laboratory parameters, treatment modalities and outcome was then investigated. RESULTS: Of the 639 victims with renal dysfunction, 348 (54%) were males and 291 (46%) females. Mean age was 33 +/- 14 and 31 +/- 15 years in the male and female victims, respectively. At admission, males were characterized by a higher hematocrit and higher serum levels of creatinine, BUN, potassium and phosphorus, while other clinical and laboratory parameters as well as the number of fasciotomized and amputated extremities did not differ between the two genders. Males suffered from longer periods of oliguria, higher rates of sepsis and hypertension. 77.3% of the male patients needed dialysis support as compared to 71.5% in the females. The number of hemodialysis sessions and days for dialysis support were higher in the males. Last serum creatinine before discharge from the nephrology clinics was higher in male victims, while mortality rates were similar in both genders. CONCLUSION: Although males are characterized by more severe laboratory abnormalities of rhabdomyolysis, more frequently suffer from sepsis and need more intensive dialysis support, gender is not a prognostic indicator of final outcome in the renal victims of disasters.

Adolescent↗

PubMedDate not supplied

A rare post-transplant malignancy, cerebellar hemangioblastoma: a case report.

INTRODUCTION: Post-transplant malignancies are among the most important complications in organ transplantation. Hemangioblastoma (HB) is especially prevalent in the cerebellum. CASE REPORT: A 20-year-old male who first started dialysis therapy, and then underwent kidney transplantation from a living-relative donor. Five years after transplantation, the patient suffered from vertigo and imbalance when walking. On cranial magnetic resonance imaging (MRI), a mass lesion in the right cerebellar hemisphere was observed, 3 x 3 x 3 cm in size, which was pushing against the fourth ventricle, and the right cerebellar peduncle. The patient had significant hydrocephaly. The mass lesion was removed by craniectomy. The pathological diagnosis was cerebellar hemangioblastoma. The symptoms and clinical findings improved. The patient was diagnosed with sporadic hemangioblastoma. Rapamycin therapy was started instead of cyclosporine, and the patient is being followed up without further problems. DISCUSSION: HB causes 2% of all intracranial tumors in the general population. It is generally sporadic in nature and approximately 20% can be associated with von Hippel-Lindau (VHL) syndrome. As in this case, MRI is preferred for the diagnosis. There was no pathology related to VHL disease in this patient's physical examination, family history, routine biochemical tests and abdominal MRI. The treatment is surgical excision of the tumor, as in this case. CONCLUSION: When cerebellar symptoms occur or a cerebellar mass lesion is detected in an organ recipient, HB should be considered in the differential diagnosis. The examination of patients with HB for a possible association with VHL disease is also required.

Adult↗