40 research outputs found
Common Methylenetetrahydrofolate Reductase Polymorphisms (A1298C & C677T) in Ectopic Trophoblasts and Methotrexate Treatment Failure in Tubal Pregnancies
Objectives: The success rate of methotrexate (MTX) therapy varies among tubal ectopic pregnancies. Commonmethylenetetrahydrofolate reductase (MTHFR) polymorphisms (C677T&A1298C) have been suggested to alter MTX effect. This study aimed to assess and compare MTX treatment failure rates with respect to MTHFR polymorphisms in trophoblasts of ectopic tubal pregnancies.Material and methods: A retrospective chart review of tubal ectopic pregnancies was conducted and 34 eligible cases were found. Paraffinized blocks of ectopic trophoblastic tissues were retrieved from the archives of pathology department.Common MTHFR polymorphisms were studied on microdissected trophoblastic tissues. Sixteen cases with history of failed MTX therapy (study group) and 18 control cases were compared for their pertinent clinical characteristics and common MTHFR polymorphisms (C677T&A1298) data.Results: In the study group, there were 8 (50%) C677T single nucleotide polymorphisms (SNP) and 9 (56.7%) A1298C SNP. Polymorphism rates were not found to be different between two groups for neither polymorphism (p > 0.05 for both). Number of compound heterozygotes was 3 (18.7%) in study group and 5 (27.7%) in controls (p = 0.693). In addition, MTHFR polymorphism presence seemed to have no effect on interval serum β-hCG concentration change in MTX-fail group (p=0.693).Conclusions: Our data implied that common MTHFR polymorphisms of ectopic trophoblastic tissue are not associated with MTX failure in patients with tubal pregnancies. Additionally, serum β-hCG concentration changes caused by MTX treatment and studied MTHFR polymorphisms are likely independent
Targeted surveillance to assess the presence of BSE in the age risk population of cattle slaughtered in Bursa, Turkey: preliminary results of an immunohistochemical detection study for the 2004-2005 period
Bovine spongiform encephalopathy (BSE), a member of the transmissible spongiform encepahlopathies, has been a notifiable disease in Turkey since 1997. In 2002, the BSE status of Turkey was assessed by the EU Scientific Steering Committee as "it is likely but not confirmed".This study presents the results of a targeted surveillance study to assess the presence of BSE in the age risk population of Bursa, Turkey. In the assessment procedure, the immunohistochemical detection of protease-resistant prion protein (PrP-Sc) was aimed at and applied to 420 brain tissues of cattle slaughtered in Bursa at an age of 30-months and older. None of the samples were positive for BSE
The Ki-67 proliferation index predicts recurrence-free survival in patients with dermatofibrosarcoma protuberans
Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue sarcoma that originates from the dermis or subcutaneous tissue in the skin. While its prognosis is generally favorable, disease recurrence is relatively frequent. Because morbidity after repeated surgery may be significant, an optimized prediction of recurrence-free survival (RFS) has the potential to improve current management strategies. The purpose of this study was to investigate the prognostic value of the Ki-67 proliferation index with respect to RFS in patients with DFSP. We retrospectively analyzed data from 45 patients with DFSP. We calculated the Ki-67 proliferation index as the percentage of immunostained nuclei among the total number of tumor cell nuclei regardless of the intensity of immunostaining. We constructed univariate and multivariate Cox proportional hazards regression models to identify predictors of RFS. Among the 45 patients included in the study, 8 developed local recurrences and 2 had lung metastases (median follow-up: 95.0 months; range: 5.2−412.4 months). The RFS rates at 60, 120, and 240 months of follow-up were 83.8%, 76.2%, and 65.3%, respectively. The median Ki-67 proliferation index was 14%. Notably, we identified the Ki-67 proliferation index as the only independent predictor for RFS in multivariate Cox proportional hazards regression analysis (hazard ratio = 1.106, 95% confidence interval = 1.019−1.200, p = 0.016). In summary, our results highlight the potential usefulness of the Ki-67 proliferation index for facilitating the identification of patients with DFSP at higher risk of developing disease recurrences
Prognostic factors for regorafenib treatment in patients with refractory metastatic colorectal cancer: A real-life retrospective multi-center study
Regorafenib, an oral multikinase inhibitor, has improved survival in metastatic colorectal cancer (mCRC) patients who have progressed on standard therapies. Our study aimed to evaluate prognostic factors influencing regorafenib treatment and assess the optimal dosing regimen in a real-life setting. We retrospectively analysed 263 patients with mCRC from multiple medical oncology clinics in Turkey. Treatment responses and prognostic factors for survival were evaluated using univariate and multivariate analysis. Of the patients, 120 were male, and 143 were female; 28.9% of tumors were located in the rectum. RAS mutations were present in 3.0% of tumors, while BRAF, K-RAS, and N-RAS mutations were found in 3.0%, 29.7%, and 25.9% of tumor tissues, respectively. Dose escalation was preferred in 105 (39.9%) patients. The median treatment duration was 3.0 months, with an objective response rate (ORR) of 4.9%. Grade ≥ 3 treatment-related toxicity occurred in 133 patients, leading to discontinuation, interruption, and modification rates of 50.6%, 43.7%, and 79.0%, respectively. Median progression-free survival (PFS) and overall survival (OS) were 3.0 and 8.1 months, respectively. RAS/RAF mutation (hazard ratio [HR] 1.5, 95% confidence interval [CI] 1.1-2.3; P = 0.01), pretreatment carcinoembryonic antigen (CEA) levels (HR 1.6, 95% CI 1.1-2.3; P = 0.008), and toxicity-related treatment interruption or dose adjustment (HR 1.6, 95% CI 1.1-2.4; P = 0.01) were identified as independent prognostic factors for PFS. Dose escalation had no significant effect on PFS but was associated with improved OS (P < 0.001). Independent prognostic factors for OS were the initial TNM stage (HR 1.3, 95% CI 1.0-1.9; P = 0.04) and dose interruption/adjustment (HR 0.4, 95% CI 0.2-0.9; P = 0.03). Our findings demonstrate the efficacy and safety of regorafenib. Treatment line influences the response, with dose escalation being more favorable than adjustment or interruption, thus impacting survival
SATELLITE ATTITUDE CONTROL USING DISSIMILAR REDUNDANT ACTUATORS
Low Earth orbit satellites are usually equipped with magnetic torquers for momentum dumping and reaction wheels to carry out three axis attitude stabilization and control. These two different types of actuators mixed and used together to carry out slew maneuvers. The problem of allocating the control to these different types of actuators is realized using a recently developed algorithm called blended inverse. The algorithm is compared with the Moore-Penrose pseudo inverse demonstrating its success in realizing the desired maneuver while overcoming singularities
System Identification of a Six-Span Steel Railway Bridge Using Ambient Vibration Measurements at Different Temperature Conditions
This paper presents modal parameter estimation work on a steel railway bridge at three different temperature conditions using ambient vibration test data. The bridge was built at the end of the 19th century using the available technology of its time. It is composed of six spans, each 30 m long, with a total length of 180 m. It is slightly curved in the horizontal plane with a radius of 300 m, and has a vertical grade of 2.5%. Modal parameters of the bridge were estimated using two different output-only system identification methods. The identified results obtained under different temperature conditions were compared in assessing the effects of temperature variation in the identification results. A comparative study in assessing method-to-method and test-to-test variability was also conducted. A three-dimensional finite-element model of the bridge was developed. In order to match the experimentally obtained modal parameters with the numerical ones, a trial-and-error-based model updating study was conducted. This way, a benchmark model of the 199+325 steel railway bridge was obtained for future capacity assessment, prediction, and sensitivity-based model updating work. (C) 2019 American Society of Civil Engineers