327 research outputs found
VerkĂŒrzung eines humanen Chromosoms 7 durch Telomer-verursachte Chromosomenfragmentierung als Basis zur Erzeugung eines artifiziellen SĂ€ugerchromosoms
Pennsylvania Folklife Vol. 26, No. 5
âą Swiss Mennonite Family Names: An Annotated Checklist âą The Dogtrot House and its Pennsylvania Associations âą A Letter from Pastor Johann Friedrich Ernst âą Civil War Medicine: A Patient\u27s Account âą Soups, Stews, Broths, and Porridges: Folk-Cultural Questionnaire No. 48https://digitalcommons.ursinus.edu/pafolklifemag/1073/thumbnail.jp
Effect of hormone replacement therapy on vasomotor function of the coronary microcirculation in post-menopausal women with medically treated cardiovascular risk factors
Aims The aim of this study was to evaluate the effect of hormone replacement therapy (HRT) on coronary vasomotor function in post-menopausal women (PM) with medically treated cardiovascular risk factors (RFs) in a cross-sectional and a longitudinal follow-up (FU) study. Methods and results Myocardial blood flow (MBF) response to cold pressor testing (CPT) and during pharmacologically induced hyperaemia was measured with positron emission tomography in pre-menopausal women (CON), in PM with HRT and without HRT, and repeated in PM after a mean FU of 24 ± 14 months. When compared with CON at baseline, the endothelium-related change in MBF (ÎMBF) to CPT progressively declined in PM with HRT and without HRT (0.35 ± 0.23 vs. 0.24 ± 0.20 and 0.16 ± 0.12 mL/g/min; P = 0.171 and P = 0.021). In PM without HRT and in those with HRT at baseline but with discontinuation of HRT during FU, the endothelium-related ÎMBF to CPT was significantly less at FU than at baseline (0.05 ± 0.19 vs. 0.16 ± 0.12 and â0.03 ± 0.14 vs. 0.25 ± 0.18 mL/g/min; P = 0.023 and P = 0.001), whereas no significant change was observed in PM with HRT (0.19 ± 0.22 vs. 0.23 ± 0.22 mL/g/min; P = 0.453). Impaired hyperaemic MBFs when compared with CON were not significantly altered from those at baseline exam. Conclusion Long-term administration of oestrogen may contribute to maintain endothelium-dependent coronary function in PM with medically treated cardiovascular RF
Improvement in coronary endothelial function is independently associated with a slowed progression of coronary artery calcification in type 2 diabetes mellitus
Aims To examine a relationship between alterations of structure and function of the arterial wall in response to glucose-lowering therapy in type 2 diabetes mellitus (DM) after a 1-year follow-up (FU). Methods and results In DM (n = 22) and in healthy controls (n = 17), coronary artery calcification (CAC) was assessed with electron beam tomography and carotid intima-media thickness (IMT) with ultrasound, whereas coronary function was determined with positron emission tomography-measured myocardial blood flow (MBF) at rest, during cold pressor testing (CPT), and during adenosine stimulation at baseline and after FU. The decrease in plasma glucose in DM after a mean FU of 14 ± 1.9 months correlated with a lower progression of CAC and carotid IMT (r = 0.48, P †0.036 and r = 0.46, P †0.055) and with an improvement in endothelium-related ÎMBF to CPT and to adenosine (r = 0.46, P †0.038 and r = 0.36, P †0.056). After adjusting for metabolic parameters by multivariate analysis, the increases in ÎMBF to CPT after glucose-lowering treatment remained a statistically significant independent predictor of the progression of CAC (P †0.001 by one-way analysis of variance). Conclusion In DM, glucose-lowering treatment may beneficially affect structure and function of the vascular wall, whereas the observed improvement in endothelium-related coronary artery function may also mediate direct preventive effects on the progression of CA
Evaluating semi-supervision methods for medical image segmentation: applications in cardiac magnetic resonance imaging
PURPOSE:
Purpose
Neural networks have potential to automate medical image segmentation but require expensive labeling efforts. While methods have been proposed to reduce the labeling burden, most have not been thoroughly evaluated on large, clinical datasets or clinical tasks. We propose a method to train segmentation networks with limited labeled data and focus on thorough network evaluation. APPROACH: We propose a semi-supervised method that leverages data augmentation, consistency regularization, and pseudolabeling and train four cardiac magnetic resonance (MR) segmentation networks. We evaluate the models on multiinstitutional, multiscanner, multidisease cardiac MR datasets using five cardiac functional biomarkers, which are compared to an expertâs measurements using Linâs concordance correlation coefficient (CCC), the within-subject coefficient of variation (CV), and the Dice coefficient. RESULTS: The semi-supervised networks achieve strong agreement using Linâs CCC (>0.8), CV similar to an expert, and strong generalization performance. We compare the error modes of the semi-supervised networks against fully supervised networks. We evaluate semi-supervised model performance as a function of labeled training data and with different types of model supervision, showing that a model trained with 100 labeled image slices can achieve a Dice coefficient within 1.10% of a network trained with 16,000+ labeled image slices. CONCLUSION: We evaluate semi-supervision for medical image segmentation using heterogeneous datasets and clinical metrics. As methods for training models with little labeled data become more common, knowledge about how they perform on clinical tasks, how they fail, and how they perform with different amounts of labeled data is useful to model developers and users
Diversity, Equity, and Inclusiveness in Medicine and Cardiology: Next Steps for JAHA.
We, the Editors of the Journal of the American Heart Association, sincerely regret the publication of the article "Diversity, Inclusion, and Equity: Evolution of Race and Ethnicity Considerations for the Cardiology Workforce in the United States of America From 1969 to 2019".1 We are aware that the publication of this flawed and biased article has caused a great deal of unnecessary pain and anguish to a number of parties, and reflects extremely poorly on us. We fully support the retraction of this article
Deoxyglucose method for the estimation of local myocardial glucose metabolism with positron computed tomography
The deoxyglucose method originally developed for measurements of the local cerebral metabolic rate for glucose has been investigated in terms of its application to studies of the heart with positron computed tomography (PCT) and FDG. Studies were performed in dogs to measure the tissue kinetics of FDG with PCT and by direct arterial-venous sampling. The operational equation developed in our laboratory as an extension of the Sokoloff model was used to analyze the data. The FDG method accurately predicted the true MMRGlc even when the glucose metabolic rate was normal but myocardial blood flow (MBF) was elevated 5 times the control value or when metabolism was reduced to 10% of normal and MBF increased 5 times normal. Improvements in PCT resolution are required to improve the accuracy of the estimates of the rate constants and the MMRGlc
Digitale Bildarchive fĂŒr Kultur und Wissenschaft
Die Forderung der Deutschen Forschungsgemeinschaft und der Allianz der deutschen Wissenschaftsorganisationen nach öffentlichem und nachhaltigem Zugang zu wissenschaftlichen Daten in Verbindung mit nicht-kommerzieller Technologie zeigt auf, dass die PrĂ€sentation von digitalen Inhalten und die Langzeitarchivierung eine immer wichtigere Rolle einnimmt. Fasst man den Blick weiter und betrachtet Wissenschaft und Kultur allgemein, so droht, durch die hohe FlĂŒchtigkeit der digital gespeicherten Informationen, dass bedeutsame Daten auf Dauer verloren gehen. Daher ist die Sicherstellung der zukĂŒnftigen Lesbarkeit und Interpretierbarkeit der digitalen Daten von entscheidender Bedeutung. Zur digitalen Langzeitarchivierung bzw. LangzeitverfĂŒgbarmachung werden Strategien benötigt, die die Erhaltung der dauerhaften VerfĂŒgbarkeit und damit eine Nachnutzung und Interpretierbarkeit der digital gespeicherten Informationen ermöglichen. Dies kann nur durch Auswahl eines geeigneten Archivsystems, bestimmter Dateiformate und Einsetzung weit verbreiteter Metadaten-Standards erreicht werden. Ein solches System, das kollaboratives Arbeiten und Langzeitarchivierung gleichermaĂen ermöglicht, ist das Bildverwaltungssystem âImejiâ. Der folgende Text fĂŒhrt einzelne Merkmale von Imeji aus und stellt zwei Fallbeispiele der Anwendung vor
Simplifying cardiovascular magnetic resonance pulse sequence terminology.
We propose a set of simplified terms to describe applied Cardiovascular Magnetic Resonance (CMR) pulse sequence techniques in clinical reports, scientific articles and societal guidelines or recommendations. Rather than using various technical details in clinical reports, the description of the technical approach should be based on the purpose of the pulse sequence. In scientific papers or other technical work, this should be followed by a more detailed description of the pulse sequence and settings. The use of a unified set of widely understood terms would facilitate the communication between referring physicians and CMR readers by increasing the clarity of CMR reports and thus improve overall patient care. Applied in research articles, its use would facilitate non-expert readers' understanding of the methodology used and its clinical meaning
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