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Öğe Comparision of ureteral stent colonization between deceased and live donor renal transplant recipients(Elsevier Science Inc, 2017) Sarıer, M.; Seyman, D.; Tekin, S.; Duman, I.; Uygun, B.; Demir, M.; Yavuz, A. H.Background. The use of a ureteral stent can cause a urinary tract infection (UTI), although it reduces urologic complications. UTIs are associated with a higher rate of ureteral stent colonization (USC). The aim of this study was to compare USC in living and deceased donor renal transplant recipients. Material and Methods. We conducted a prospective study of 48 patients who underwent renal transplantation between January and December 2016. The stents were removed aseptically, the inner surface of proximal and distal ends of stents were irrigated with liquid culture medium, and then they were vortexed for bacteriological investigation. Urine cultures were taken at the same time. Results. A total of 45 renal transplantation patients (21 from cadavers, 24 from live donors) were evaluated in the study. The duration time of stent retention in patients with live donors was 25.04 +/- 4.55 and in patients with deceased donors was 26.19 +/- 4.08 days (P = .376). USC was observed in 12 (57.1%) and 6 (25%) patients while positive urine culture (PUC) was detected in 5 (23.8%) and 2 (8.3%) patients in deceased and live donor transplant recipients, respectively. Although the USC rate was significantly higher in the deceased donor renal transplant group (P = .022), there was no significant different in the rates of PUC (P = .137). Enterecoccus species was the common pathogen isolated from ureteral stent and urine. The micro-organisms isolated from ureteral stent in deceased and live donors, respectively, were distributed as follows: Enterococcus 5/3, Candida 3/1, Escherichia coli 2/1, Kebsiella pneumonia 1/1, and staphylococci in 1/0 patients. All E coli and K pneumoniae are extended spectrum beta-lactamase (ESBL)-positive isolates and resistant to sulfamethoxazole-trimethoprim (SMX/TMP). Conclusions. We report a high incidence of USC in deceased renal transplants. Enterecoccus instead of E coli is the most common pathogen during the first month after transplantation. Transplantation centers should be aware that deceased donor renal transplant recipients are more prone to stent-related infection and the antibacterial resistance rapidly increases in uropathogens.Öğe Desing of experimental liver phantom with multifocal tumor implication for use in yttrium 90 radioembolization dosimetry(Springer, 2018) Tanyıldızı, Handan; Karadeniz, A.; Demir, M.; Kabasakal, L.[No abstract available]Öğe Donors with hepatitis B surface antigen positivity(Elsevier Science Inc, 2015) Yavuz, H. Asuman; Tekin, S.; Yüksel, Y.; Ateş, I.; Yücetin, L.; Demir, M.; Demirbaş, A.Objective. There is a still controversy among transplantation centers regarding acceptance of hepatitis B surface antigen (HBsAg)-positive donors for renal transplantation. However, some reports show that these donors can be used under a special protocol. In this study, we compared the clinical and biochemical parameters of patients who received kidneys from HBsAg-positive (group 1) versus other living-related kidney donors (group 2). Materials and Methods. We retrospectively analyzed the outcomes of 2168 living-related renal transplantations performed between December 2008 and April 2014 at Medical Park Hospital Transplantation Center, Antalya, Turkey. One hundred eleven donors were HbsAg-positive (group 1), and 2057 donors were HbsAg-negative (group 2). Group 1 kidney transplantations were undertaken only if the recipient displayed a hepatitis B antibody titer >10 mIU/mL and donor hepatitis B virus DNA was negative. Results. Demographic characteristics; 1-, 2- and 4-year serum creatinine levels; glomerular filtration rates; and liver function test results were similar between the two groups. There were no new hepatitis B virus infections throughout the study period. Acute rejection rates (26/111 in group 1 vs 375/2168 in group 2; P = .887), graft loss (4/111 in group 1 vs 123/2168 in group 2; P = .546), and patient loss (6/111 in group 1 vs 102/2168; P = .132) were similar between the two groups. Conclusion. Our study showed that hepatitis B surface antigen positivity was not a contraindication to living-kidney donation.Öğe Evaluation of radiation exposure dose rates: A comparative study between the two commercially available Y-90 microsphere products therasphere and SIR-spheres(Springer, 2016) Tanyıldızı, H.; Demir, M.; Abuqebitah, M.; Çavdar, I.; Kabasakal, L.; Sönmezoğlu, K.[No abstract available]Öğe Evaluation of ureteral stent colonization in live-donor renal transplant recipients(Elsevier Science Inc, 2017) Sarıer, M.; Demir, M.; Duman, I.; Yüksel, Y.; Demirbaş, A.Background. Ureteral stent insertion during kidney transplantation is a matter of debate. Stenting has been proven to reduce the risk of surgical complications. In addition, it has been reported to increase risks such as urinary tract infections especially after operation. Ureteral stent colonization (USC) is known to play a role in the pathogenesis of stent related-infections. The aim of this study was (1) to assess the frequency of USC and values of urine cultures in identifying colonizing bacteria; (2) to assess the importance of indwelling time for USC in live-donor renal transplant recipients; and (3) to evaluate the biomarker role of neutrophil-to-lymphocyte ratio (NLR) on USC. Methods. A total of 107 live-donor kidney transplant patients were included in the study (76 men and 31 women). The mean age was 43.7 years, and average indwelling time of the ureteral stent was 24.7 days. Patients were divided into three groups according to indwelling stent time as group 1: 15 to 21 days (3rd week), group 2: 22 to 28 days (4th week), and group 3: 29 to 35 days (5th week). The decision to remove the stent was primarily based on clinical judgment. Ureteral stents were removed with the use of flexible cystoscopy. Midstream urine for urine culture and blood samples for NLR were taken prior to stent removal. The removed stents were divided into three parts and taken for bacteriological investigation. Results. Of 107 patients, USC was detected in 24 (22.4%) patients, whereas urinary proliferation was observed in 8 (7.4%) patients. The most common microorganisms found in USC was the Enterecoccus species. The most common microorganisms in urinary culture were Enterecoccus spp. and Klebsiella pnemoniae. All patients with isolated microorganisms in the urine had USC (P < .001). On the other hand, proliferation in urinary culture was observed only in 30% of patients. Urine culture was not significant in identification of USC (P = .063). The three patient groups that were determined according to indwelling stent time were compared in terms of USC, proliferation in urine culture, and NLR. The highest incidence of USC was found in group 3 (44%) and the least in group 2 (11%) (P < .05). No significant difference was found between the groups in terms of urine culture (P = .546). Although no significant difference was found between groups 1 and 2 in NLR values (P = .755), NLR was significantly higher in group 3 (P = .026). Conclusions. Colonization is common in ureteral stents inserted in live-donor kidney transplant patients, although routine urine culture is insufficient in identfying this colonization. The most common microorganism detected in ureteral stent colonization was Enterecoccus spp. The 4th week was the most convenient time for stent removal time in terms of USC among the 3rd, 4th, and 5th weeks. In addition, increased NLR might have value as a biomarker for USC.Öğe Results of real-time multiplex polymerase chain reaction assay in renal transplant recipients with sterile pyuria(Elsevier Science Inc, 2017) Sarıer, M.; Demir, M.; Göktaş, S.; Duman, I.; Büyükkınacı, M.; Yüksel, Y.; Şengül, A.; Yavuz, A. H.Urinary tract infections are a major cause of morbidity and hospitalization after renal transplantation. Patients treated with immunosuppressive drugs suffer not only from common uropathogens but also from opportunistic infections caused by unusual uropathogens. Sterile pyuria is associated with numerous infectious agents including viruses, fungi, and atypical or fastidious organisms. The objective of this study was to investigate the pathogens using real-time multiplex polymerase chain reaction (rtMPCR) assay in sterile pyuria of renal transplant recipients. In this prospective controlled study, pathogen detection was performed with rtMPCR assay on October 2016 in 60 patients with sterile pyuria who had undergone kidney transplantation. A total of 40 renal transplant patients were determined as the control group. Male-to-female ratio was same. The mean age of the subjects with sterile pyuria was 45.7 +/- 12.1 (25-74). The mean duration after transplantation was 28.8 +/- 3.97 (3-102) months. Pathogens were detected with rtMPCR in 61.7% of sterile pyuria group. This rate was significantly higher compared with the control group (P < .001). Two or more different pathogens were found in 13 (21.7%) patients in sterile pyuria group. The pathogens found included cytomegalovirus in 10 patients (19%), Gardnerella vaginalis and obligate anaerobes in 20 patients (38%), Ureaplasma spp in 17 patients (33%), Candida spp in 2 patients (4%), Mycoplasma hominis in one patient (2%), herpes simplex virus-2 in one patient (2%), and Trichomonas vaginalis in one patient (2%). Sterile pyuria may indicate the presence of genitourinary pathogens that cannot be detected with conventional urine culture method in renal transplantation patients. rtMPCR is an accurate and convenient method for detection of multiple potential pathogens of sterile pyuria in renal transplant patients.Öğe Y-90 dosimetry with Monte Carlo method: GATE validation with STL formatted phantom(Polish Acad Sciences Inst Physics, 2020) Kökkülünk, H. Tanyıldızı; Demir, M.; Yıldırım, A. Karadeniz; Özkorucuklu, S.; Akkuş, B.; Yaşar, D.In Y-90 treatment, it is important to implement patient-specific dosimetry. The study was aimed at creating an STL-based liver model phantom with multiple tumor mimics to test the GATE program and to perform Y-90 dosimetry with the Monte Carlo method. First, the liver model phantom with the outer dimensions of 22 x 14 x 8 cm(3) was made of plexiglass and two cylindrical tumor mimics were placed in it. (99mTc) activities with 62.9 MBq and 7 MBq were placed in both tumor mimics. Thermoluminescent dosimeters were used at 10 positions in the liver model phantom. Next, the same conditions were simulated in GATE and the absorbed doses were determined with DoseActors. After GATE validation, the absorbed doses were calculated for Y-90 source of 40.7 MBq. Based on this, the absorbed doses were estimated for the average amount of therapeutic Y-90 activity. The average instant absorbed doses in the liver model phantom for Tc-99m activities were found to be between 0.337 +/- 0.002 and 0.0059 +/- 0.0008 mu Gy/s via thermoluminescent dosimeters and between 0.367 +/- 0.002 and 0.0052 +/- 0.0003 mu Gy/s via GATE. When the Tc-99m results were compared, the mean overlap ratio and R-squared value were 10.68% and 0.9966, respectively. The mean absorbed doses in the first tumor mimic, the second tumor mimic and normal liver parenchymal tissue were 1350.0 +/- 7:7, 450.0 +/- 4.4 and 3.9 +/- 0.2 Gy for 1480 MBq therapeutic Y-90 activity. The GATE simulation showed significantly similar dosimetric results with the thermoluminescent dosimeter measurement for a liver dose calculation. As the tumor and liver dose estimation is a key limiting factor in Y-90 dosimetry, the practical application of the GATE simulation is an advantage for dose calculations and can improve the dosimetry.
