Browsing by Subject "frequency"
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Item Is Monitoring of Cytomegalovirus Disease Required in Nontransplant Pediatric Acute Lymphoblastic Leukemia?(Lippincott Williams and Wilkins, 2021) Şen S.; Özdemir H.H.; Karadaş N.; Bal Z.Ş.; Göktepe Ş.Ö.; Ece D.; Balkan C.; Aydinok Y.; Karapinar D.Y.Introduction: Cytomegalovirus (CMV) infections in developing countries are experienced at an early age. This study was performed to investigate the frequency of reactivation and risk factors of infection acquired at an early age of nontransplant acute lymphoblastic leukemia (ALL) patients receiving immunosuppressive therapy with weekly monitoring of CMV levels in Turkey. Materials and Methods: This was a retrospective, single-center study of 172 pediatric patients (102 boys and 70 girls) with ALL. All patients were monitored routinely for CMV-DNA at the initial presentation of leukemia and twice a week during chemotherapy. The CMV immunoglobulin (Ig)M/IgG titers were measured at admission. Results: CMV seropositivity at baseline was 90,11%. The overall prevalence of CMV infection (viremia) was 70.34%, 116 of whom were seropositive for CMV IgG and 5 of whom were negative for CMV at the time of ALL diagnosis. Reactivation was more common than de novo CMV infections (P=0.000). CMV seropositivity at the beginning of the leukemia diagnosis was found to be an independent predictor for developing CMV infection (P=0.001). A total of 60 CMV infection episodes were treated with antivirals. Four of these included organ involvement. The duration of CMV-DNA viremia episodes was longer in patients with CMV-DNA ≥1000 copies/mL (n=45) than in those with lower CMV-DNA levels (P=0.002). Infection was shown not to be associated with chemotherapy phase. Conclusion: This study suggests the importance of monitoring for CMV infections in developing countries because of frequent reactivations in seropositive ALL patients. It should be kept in mind that low CMV-DNA levels may also lead to organ involvement. © 2021 Lippincott Williams and Wilkins. All rights reserved.Item Thermoluminescence in GdAl3(BO3)4 phosphors: Unusual heating rate dependencies, dose responses and kinetic parameters(Elsevier Ltd, 2023) Alajlani Y.; Sonsuz M.; Barad A.; Kaynar Ü.H.; Ayvacikli M.; Topaksu M.; Can N.The current study focuses on the production of GdAl3(BO3)4 (GAB) phosphors using gel combustion. X-ray diffraction (XRD) and thermoluminescent (TL) methods were used to investigate the structural and thermoluminescence (TL) features of the samples. XRD results revealed that GAB phosphors were crystallized in a rhombohedral crystal system. TL experimental data exhibited an unusual heating rate behaviour, which was explained by the semi-localized transition model, and this provides valuable insight into the properties of the GAB sample. Beta-irradiated GAB hosts exhibit two primary peaks at 106 °C and 277 °C on their TL glow curves. We have employed a variety of heating rates (VHRs), TM-Tstop method, and computerized glow curve deconvolution (CGCD) techniques. By using a combination of these techniques, we can identify the kinetic parameters of the GAB samples more accurately, including peak numbers, activation energy, and frequency factors. Both Tm-Tstop and CGCD techniques produce similar results in terms of trap numbers and trap depths. In the trap centers, electrons were trapped at 1.05 eV, 0.84 eV, 1.12 eV, 1.20 eV, 1.42 eV, 1.63 eV and 1.42 eV. There was a linear behaviour of GAB samples over a dose range of 0.1 Gy–10 Gy. GAB phosphors did not show any significant changes in TL response with repeated irradiation cycles, suggesting that it is a reliable radiation dosimeter. GAB is therefore a potential candidate for radiotherapy dose measurement based on these findings. © 2023 Elsevier LtdItem Histopathological Results of Conjunctival Masses with Suspected Malignancy Based on Slit-lamp Biomicroscopy(College of Physicians and Surgeons Pakistan, 2023) Erdogan M.; Mayali H.; Malgaz S.; Altinisik M.; Ilker S.S.Objective: To evaluate the histopathological results of conjunctival masses suspected to be malignant based on biomicroscopic examination. Study Design: Observational study. Place and Duration of the Study: Department of Ophthalmology, Celal Bayar University, Hafsa Sultan Hospital, Manisa, Turkiye, from November 2013 to February 2021. Methodology: Patients who underwent excision for the diagnosis and treatment of conjunctival surface masses with clinical suspicion of malignancy were evaluated retrospectively. The masses were categorised as benign, premalignant, and malignant lesions according to the histopathological results. The distribution of conjunctival masses was analysed according to patients’ gender and age groups. Results: The study included 98 conjunctival masses in 98 patients (57.1% men, mean age 48.6±21.85 years). On pathological examination, 63 of the masses were found to be benign (64.3%), 22 were premalignant (22.4%), and 13 were malignant (13.3%). The most common benign lesion was nevus (n=21, 21.4%). All detected premalignant lesions were conjunctival intraepithelial neoplasms (CIN), detected in 22 patients (22.4%). Of these, 13 patients (13.3%) had carcinoma in situ (CIN III). Thirteen (13.3%) of the masses were malignant, the most common being squamous cell carcinoma (n=10, 10.2%). The frequency of premalignant and malignant lesions increased with age (p<0.001). There was no statistical relationship between malignancy and gender (p=0.619). Conclusion: Most conjunctival masses in this series were benign, with nevi being the most common. The most common premalignant and malignant lesions were intraepithelial neoplasia and squamous cell carcinoma, respectively. Malignant conjunctival lesions were more common in older patients. © 2023 College of Physicians and Surgeons Pakistan. All rights reserved.Item Central nervous system thrombosis in pediatric acute lymphoblastic leukemia in Turkey: A multicenter study(John Wiley and Sons Inc, 2023) Guzelkucuk Z.; Karapınar D.Y.; Gelen S.A.; Tokgoz H.; Ozcan A.; Ay Y.; Bahadır A.; Ozbek N.Y.; Oren A.C.; Ayhan A.C.; Akyay A.; Akıncı B.; Karadas N.; Unuvar A.; Oren H.; Fettah A.; Kaya Z.; Isık B.; Eker İ.; Karaman S.; Yıldırım A.T.; Orhan M.F.; Oymak Y.; Timur C.; Yazici N.; Simsek A.; Karakurt N.; Toret E.; Evim M.S.Background: In patients with acute lymphoblastic leukemia (ALL), the risk of thromboembolism increases due to hemostatic changes secondary to the primary disease and due to treatment-related factors. In this multicenter study, we aimed to research the frequency of central nervous system (CNS) thrombosis occurring during treatment, hereditary and acquired risk factors, clinical and laboratory features of patients with thrombosis, treatment approaches, and thrombosis-related mortality and morbidity rates in pediatric ALL patients. Procedure: Pediatric patients who developed CNS thrombosis during ALL treatment from 2010 to 2021 were analyzed retrospectively in 25 different Pediatric Hematology Oncology centers in Türkiye. The demographic characteristics of the patients, symptoms associated with thrombosis, the stage of the leukemia treatment during thrombosis, the anticoagulant therapy applied for thrombosis, and the final status of the patients recorded through electronic medical records were determined. Results: Data from 70 patients with CNS thrombosis during treatment, out of 3968 pediatric patients with ALL, were reviewed. The incidence of CNS thrombosis was 1.8% (venous: 1.5 %; arterial: 0.03%). Among patients with CNS thrombosis, 47 had the event in the first 2 months. Low molecular weight heparin (LMWH) was the most commonly used treatment with a median of 6 months (min–max: 3–28 months). No treatment-related complications occurred. Chronic thrombosis findings occurred in four patients (6%). In five (7%) patients who developed cerebral vein thrombosis, neurological sequelae (epilepsy and neurological deficit) remained. One patient died related to thrombosis, and the mortality rate was 1.4%. Conclusion: Cerebral venous thrombosis and, less frequently, cerebral arterial thrombosis may develop in patients with ALL. The incidence of CNS thrombosis is higher during induction therapy than during other courses of treatment. Therefore, patients receiving induction therapy should be monitored carefully for clinical findings suggestive of CNS thrombosis. © 2023 Wiley Periodicals LLC.