93 research outputs found
Comparison of the diagnostic accuracy of diffusion-weighted magnetic resonance imaging and positron emission tomography/computed tomography in pulmonary nodules : a prospective study
Purpose: Computed tomography (CT) and positron emission tomography (PET) are the mainstay imaging methods in the evaluation and follow-up of pulmonary nodules. But they both have high radiation risk for patients. Diffusionweighted magnetic resonance imaging (DW-MRI), on the other hand, is a radiation free imaging method that gives information about the biological structure of tissues at the molecular level by measuring random movement of water in biological tissues. In this prospective study we aimed to compare the computed tomography characteristics of the nodules in terms of malignancy and to compare the accuracy of DW-MRI and PET/CT results in those patients. Material and methods: Seventy-six patients suspicious for lung cancer on thorax CT imaging were prospectively further evaluated by thorax diffusion-weighted imaging and PET/CT. Pulmonary lesion characteristics, apparent diffusion coefficient (ADC), and maximum standardised uptake values (SUVmax) were compared with histopathological results. Results: There was statistically significant moderate negative correlation between PET-SUVmax and ADC values of lung lesions. ADC values below the cut-off was 97.1%, specificity was 97.6%, positive predictive value was 97.1%, and the negative predictive value was 97.6%. Conclusions: DAG-MRI and PET/CT have similar success in the differentiation of benign and malignant lung lesions
Adrenal cortex regeneration in ethane dimethanesulfonate administered rat model
Aim: To investigate the parallel morphological and biochemical regeneration of Leydig cells in the adrenal gland after ethane dimethanesulfonate (EDS) administration.
Materials and methods: We divided 72 male rats into two groups: the control and EDS groups. Rats in the EDS group received a single dose of EDS (75 mg/kg) intraperitoneally and were sacrificed on days 7, 21, 35, and 63 respectively. Adrenal gland tissue samples obtained from the sacrificed rats were analyzed under light microscopic, immunohistochemical, biochemical, and quantitative methods.
Results: In contrast to Caspase-3 expression, 3βHSD and Ki67 expression and thickness of the zona reticularis (ZR) layer and testosterone levels significantly decreased on the 7th, 21st, and 35th days after single-dose EDS. However, 3βHSD and Ki67 expression, testosterone levels, and the ratio of ZR thickness of the EDS group were seen similar to the control group on the 63rd day following EDS administration, but experienced decreasing Caspase-3 expression. After EDS administration, we observed a significant regeneration in the ZR layer of the adrenal gland on the 63rd day.
Conclusion: EDS-injected animal models can be used to investigate the development of Leydig cells and assess the turnover of the adrenal cortex (adrenal insufficiency) per time
Explaining retailer's ordering behavior in supply chain experiments
In this thesis, we study the retailer’s ordering behavior in a manufacturer-retailer supply chain where the retailer faces the newsvendor problem. Analytical literature predicts that the retailer will use the critical ratio solution when determining her order quantity from the manufacturer. When real human beings play the roles of manufacturer and retailer in controlled experiments, however, the retailer decisions are observed to deviate from these theoretical predictions. The deviations are due to (1) individual biases and heuristics, (2) the strategic interaction between the two players. Literature has studied the effects of individual biases and heuristics using simple newsvendor experiments. However, very few researchers have conducted experiments where both sides are human. This extension is valuable because supply chain relations in practice depend on human-to-human interaction between managers. In this study, using data from the supply chain experiments of Şahin and Kaya (2011), we aim to answer the following questions: (1) Do retailer subjects follow the heuristics observed in simple newsvendor experiments? (2) What are the factors affecting retailer decisions? (3) Do retailer subjects learn to make better decisions over time? We find that retailer behavior is highly heterogeneous. While there is support for the use of decision heuristics at the aggregate level, we have mixed results at individual level. Likewise, the factors that affect retailer order quantity are found to be subject-dependent. The extent of learning is also found to differ from subject to subject
Asthma and COVID-19
Asthma is a heterogeneous disease developed against various stimuli (indoor and outdoor allergens, cigarette, air pollution, etc.), associated with airway hypersensitivity and characterized by chronic airway inflammation. COVID-19 is a disease caused by a coronavirus strain called Severe Acute Respiratory Syndrome-coronavirus-2 (SARS-CoV-2). There may be some clinical confusions in proper diagnostics due to certain similarities of both diseases’s symptoms such as, for example, a difficulty of breathing, cough, and shortness of breath. The current data on asthma being a risk factor for COVID-19 are controversial. It has been reported that asthma is not a risk factor for COVID-19 as the course of COVID-19 in patients with asthma is similar to that observed in the normal population. On the other hand, a current guidance from the World Health Organization (WHO) suggests that asthmatic patients can get more severe illness from COVID-19. Moreover, as with all respiratory tract infections, SARS-CoV-2 virus can certainly impair asthma control. However, recent studies suggest a potential beneficial effect of corticosteroids on SARS-CoV-2 infection as they suppress type II inflammation and restore anti-viral immunity. Prolonged use of a high dose of systemic steroids can increase susceptibility to infection and the occurrence of systemic side effects. However, patients with asthma should definitely continue their prescribed treatment with inhaler steroids and other additional medicines they use during SARS-CoV-2 infection. In asthmatic patients infected with SARS-CoV-2, the most significant risk factor is the loss of asthma control and subsequent presentation to healthcare centers due to the lack of asthma control. Therefore, the asthmatic patients using biological agents are recommended to continue their prescribed treatment such as omelizumab, mopelizumab and prolong the treatment intervals during the peak of infection
Corneal Confocal Microscopy to Image Small Nerve Fiber Degeneration: Ophthalmology Meets Neurology.
Neuropathic pain has multiple etiologies, but a major feature is small fiber dysfunction or damage. Corneal confocal microscopy (CCM) is a rapid non-invasive ophthalmic imaging technique that can image small nerve fibers in the cornea and has been utilized to show small nerve fiber loss in patients with diabetic and other neuropathies. CCM has comparable diagnostic utility to intraepidermal nerve fiber density for diabetic neuropathy, fibromyalgia and amyloid neuropathy and predicts the development of diabetic neuropathy. Moreover, in clinical intervention trials of patients with diabetic and sarcoid neuropathy, corneal nerve regeneration occurs early and precedes an improvement in symptoms and neurophysiology. Corneal nerve fiber loss also occurs and is associated with disease progression in multiple sclerosis, Parkinson's disease and dementia. We conclude that corneal confocal microscopy has good diagnostic and prognostic capability and fulfills the FDA criteria as a surrogate end point for clinical trials in peripheral and central neurodegenerative diseases
The disruption of protein-protein interactions as a therapeutic strategy for prostate cancer
This is an accepted manuscript of an article published by Elsevier in Pharmacological Research on 16/08/2020, available online: https://doi.org/10.1016/j.phrs.2020.105145
The accepted version of the publication may differ from the final published version.Prostate cancer (PCa) is one of the most common male-specific cancers worldwide, with high morbidity and mortality rates associated with advanced disease stages. The current treatment options of PCa are prostatectomy, hormonal therapy, chemotherapy or radiotherapy, the selection of which is usually dependent upon the stage of the disease. The development of PCa to a castration-resistant phenotype (CRPC) is associated with a more severe prognosis requiring the development of a new and effective therapy. Protein-protein interactions (PPIs) have been recognised as an emerging drug modality and targeting PPIs is a promising therapeutic approach for several diseases, including cancer. The efficacy of several compounds in which target PPIs and consequently impair disease progression were validated in phase I/II clinical trials for different types of cancer. In PCa, various small molecules and peptides proved successful in inhibiting important PPIs, mainly associated with the androgen receptor (AR), Bcl-2 family proteins, and kinases/phosphatases, thus impairing the growth of PCa cells in vitro. Moreover, a majority of these compounds require further validation in vivo and, preferably, in clinical trials. In addition, several other PPIs associated with PCa progression have been identified and now require experimental validation as potential therapeutic loci.
In conclusion, we consider the disruption of PPIs to be a promising though challenging therapeutic strategy for Pca. Agents which modulate PPIs might be employed as a monotherapy or as an adjunct to classical chemotherapeutics to overcome drug resistance and improve efficacy. The discovery of new PPIs with important roles in disease progression, and of novel optimized strategies to target them, are major challenges for the scientific and pharmacological communities.We thank the Portuguese Foundation for Science and Technology(FCT), European Union, QREN, FEDER and COMPETE for funding iBiMED (UIDB/04501/2020, POCI-01-0145-FEDER-23007628 and UID/BIM/04501/2019) and an individual scholarship from BM (SFRH/BD/146032/2019)
A Model for Doctoral Students\u27 Perceptions and Attitudes toward Written Feedback for Academic Writing
The purpose of this study was to investigate social science doctoral students\u27 perceptions and attitudes toward different characteristics of written feedback and written feedback providers for their academic writing. Moreover, it aimed to provide an explanatory model to describe the relationships between these perceptions and attitudes, students\u27 revision decisions, and other potentially relevant factors in their written feedback practices. The investigation was informed by two theoretical frameworks: principles of instructional design and conditions of learning, and situated learning and communities of practice. The study used a mixed methods approach in which qualitative data collection and analysis was followed by quantitative data collection and analysis. The main purpose of the qualitative phase was to develop a background to build a questionnaire to be used in the quantitative phase. The qualitative data were collected through interviews with 15 participants. Grounded theory data analysis methods were adapted in the qualitative analysis of the data. The quantitative data were collected through a questionnaire with 276 participants in two large mountain west public universities. Descriptive and multivariate correlational data analyses were employed for the analysis of the quantitative data. The results of this study provided descriptive information on doctoral students\u27 preferences for different types of written feedback and their perceptions and attitudes toward different characteristics of written feedback providers. Moreover, the structural equation modeling (SEM) analysis results showed that that there are several factors in the feedback practices of the doctoral students that have significant influences on some other factors in these feedback practices. An eight-factor model was developed constituting the following factors: (a) attitudes toward critical/negative written feedback, (b) motivations for academic writing, (c) perceptions of opportunities to write academic papers with faculty members in the department, (d) attitudes toward asking and searching for written feedback for academic papers, (e) attitudes toward feedback providers\u27 willingness and time to give feedback when asking for written feedback, (f) attitudes toward feedback providers\u27 personality when asking for written feedback, (g) revision decisions considering the external issues while examining the written feedback, and (h) revision decisions considering the written feedback characteristics and the need for the revisions while examining the written feedback
Blogging in Higher Education: Theoretical and Practical Approach
ABSTRACT In this paper the blogging method, which includes new forms of writing, is supported as an alternative approach to address the frequently asserted problems in higher education such as product-oriented assessment and lack of value given to students' writing as contribution to the discourse of the academic disciplines. Both theoretical and research background information is provided to clarify the rationale of using this method in higher education. Furthermore, recommended way of using this method in courses is outlined specifically in relation to these problems
Blogging in Higher Education: Theoretical and Practical Approach
In this paper the blogging method, which includes new forms of writing, is supported as an alternative approach to address the frequently asserted problems in higher education such as product-oriented assessment and lack of value given to students' writing as contribution to the discourse of the academic disciplines. Both theoretical and research background information is provided to clarify the rationale of using this method in higher education. Furthermore, recommended way of using this method in courses is outlined specifically in relation to these problems
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