508 research outputs found

    Novel 129Xe Magnetic Resonance Imaging and Spectroscopy Measurements of Pulmonary Gas-Exchange

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    Gas-exchange is the primary function of the lungs and involves removing carbon dioxide from the body and exchanging it within the alveoli for inhaled oxygen. Several different pulmonary, cardiac and cardiovascular abnormalities have negative effects on pulmonary gas-exchange. Unfortunately, clinical tests do not always pinpoint the problem; sensitive and specific measurements are needed to probe the individual components participating in gas-exchange for a better understanding of pathophysiology, disease progression and response to therapy. In vivo Xenon-129 gas-exchange magnetic resonance imaging (129Xe gas-exchange MRI) has the potential to overcome these challenges. When participants inhale hyperpolarized 129Xe gas, it has different MR spectral properties as a gas, as it diffuses through the alveolar membrane and as it binds to red-blood-cells. 129Xe MR spectroscopy and imaging provides a way to tease out the different anatomic components of gas-exchange simultaneously and provides spatial information about where abnormalities may occur. In this thesis, I developed and applied 129Xe MR spectroscopy and imaging to measure gas-exchange in the lungs alongside other clinical and imaging measurements. I measured 129Xe gas-exchange in asymptomatic congenital heart disease and in prospective, controlled studies of long-COVID. I also developed mathematical tools to model 129Xe MR signals during acquisition and reconstruction. The insights gained from my work underscore the potential for 129Xe gas-exchange MRI biomarkers towards a better understanding of cardiopulmonary disease. My work also provides a way to generate a deeper imaging and physiologic understanding of gas-exchange in vivo in healthy participants and patients with chronic lung and heart disease

    2023 GREAT Day Program

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    SUNY Geneseo’s Seventeenth Annual GREAT Day. Geneseo Recognizing Excellence, Achievement & Talent Day is a college-wide symposium celebrating the creative and scholarly endeavors of our students. http://www.geneseo.edu/great_dayhttps://knightscholar.geneseo.edu/program-2007/1017/thumbnail.jp

    The Role of c-Myc in Regulating Cardiac Intermediary Metabolis

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    Background – The heart adapts in response to stress by inducing adaptive remodelling pathways leading to cardiac hypertrophy, however this is not sustained and with continued stress, maladaptive remodelling pathways ensue, impairing cell viability and contractile function leading to heart failure. An emerging concept is that cardiac hypertrophy is paralleled by changes in cardiomyocyte metabolism, which may themselves drive cardiac hypertrophy. The proto-oncogene c-Myc is a key regulator of cancer metabolism that promotes anabolic pathways driving tumorigenesis. Interestingly, c-Myc overexpression in the heart causes hypertrophy but how this is accomplished remains unclear.Objective – Define the functional role of c-Myc during remodelling of the adult heart with a focus on the relationship to intermediary glucose metabolism pathways that support anabolic growth in response to different types of hypertrophic stress stimuli.Methods – Cardiac-specific c-Myc knock-out (c-Myc KO) mice were generated and subjected to different types of stress stimuli. Pathological stress was induced by abdominal aortic banding (AAB) or transverse aortic constriction (TAC) and compared to sham surgery. Physiological stress was induced by voluntary wheel running (VWR) exercise and compared with sedentary controls. Metabolic pathway activity was comprehensively assessed by optimising a stable isotope resolved metabolomics method, using stable isotope labelled glucose (13C6 glucose) in ex-vivo Langendorff perfused hearts of floxed control and cs-c-Myc KO mice.Results – The c-Myc KO mice appear phenotypically normal and do not exhibit any changes in cardiac structure or function at baseline. When subjected to chronic pressure overload, c-Myc KO mice show a similar decline in cardiac function and a similar extent of cardiac hypertrophy as their floxed littermates. After chronic pressure overload, there is a significant decrease in 13C label incorporation into TCA metabolites and its related amino acids in the cs-c-Myc KO mice. In parallel, metabolites related to the hexosamine biosynthesis pathway show an increased 13C label incorporation after pressure overload in the floxed mice which is attenuated in the c-Myc KO mice. When subjected to regular exercise, c-Myc KO mice develop cardiac hypertrophy to the same extent as the floxed mice. Exercise causes an increase in the pentose phosphate pathway activity in the floxed mice which is mitigated in the c-Myc KO mice. Exercised floxed mice showed an increased lactate uptake and utilisation into the TCA cycle whereas c-Myc KO mice had decreased reliance on lactate.Conclusion – Knock-out of c-Myc alters glucose contribution to the TCA cycle and affects the diversion of glycolytic intermediates into pathways of intermediary metabolism important for anabolic growth and adaptation to stress. These results provide new insight into the rewiring of glucose carbon metabolism in the hypertrophied heart that is in part driven by c-Myc. Understanding adaptive remodelling pathways that drive cardiac hypertrophy may help lead to better treatments for preventing heart failure.<br/

    Altered morphology of white and grey matter in patients with Alzheimer disease and Schizophrenia on MRI

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    Velikost a tvar závitů (gyri) a žlábků (sulci) v oblasti přední cingulární kůry (ACC), zejména sulcus cinguli (CS) a sulcus paracingularis (PCS), představuje anatomický marker vývoje nervového systému. Odchylky ve vývoji in utero u schizofrenie lze sledovat pomocí morfometrie CS a PCS. V této studii jsme měřili délku CS, PCS a jejich segmentů na snímcích T1 MRI u 93 pacientů s první epizodou schizofrenie a u 42 zdravých kontrol. Kromě délky sulci byla u pacientů a kontrol porovnávána také frekvence výskytu a levopravá asymetrie CS/PCS. Distribuce morfotypů CS a PCS u pacientů se lišila od kontrol. Parcelovaný typ CS3a v levé hemisféře byl u pacientů delší (53,8 ± 25,7 mm oproti 32,7 ± 19,4 mm u kontrol, p < 0,05), zatímco u CS3c byl u kontrol naopak dlouhý (52,5 ± 22,5 mm oproti 36,2 ± 12,9 mm, n.s. u pacientů). Neparcelovaný PCS v pravé hemisféře byl delší u pacientů ve srovnání s kontrolami (19,4 ± 10,2 mm oproti 12,1 ± 12,4 mm, p < 0,001). Současná přítomnost PCS1 a CS1 v levé hemisféře a do jisté míry i v pravé hemisféře tedy může svědčit o vyšší pravděpodobnosti schizofrenie. Měření plochy nebo objemu hipokampu je v klinické praxi užitečné jako podpůrná pomůcka pro diagnostiku Alzheimerovy choroby. Vzhledem k tomu, že je časově náročné a není jednoduché, využívá se nepříliš často. Předkládáme...Cortical folding of the anterior cingulate cortex (ACC), particularly the cingulate (CS) and the paracingulate (PCS) sulci, represents a neurodevelopmental marker. Deviations in in utero development in schizophrenia can be traced using CS and PCS morphometry. In the present study, we measured the length of CS, PCS, and their segments on T1 MRI scans in 93 patients with first episode schizophrenia and 42 healthy controls. Besides the length, the frequency and the left-right asymmetry of CS/PCS were compared in patients and controls. Distribution of the CS and PCS morphotypes in patients was different from controls. Parcellated sulcal pattern CS3a in the left hemisphere was longer in patients (53.8 ± 25.7 mm vs. 32.7 ± 19.4 mm in controls, p < 0.05), while in CS3c it was reversed-longer in controls (52.5 ± 22.5 mm as opposed to 36.2 ± 12.9 mm, n.s. in patients). Non parcellated PCS in the right hemisphere were longer in patients compared to controls (19.4 ± 10.2 mm vs. 12.1 ± 12.4 mm, p < 0.001). Therefore, concurrent presence of PCS1 and CS1 in the left hemisphere and to some extent in the right hemisphere may be suggestive of a higher probability of schizophrenia. Measurement of an hippocampal area or volume is useful in clinical practice as a supportive aid for diagnosis of Alzheimer's disease....Ústav anatomie 3. LF UKDepartment of Anatomy 3FM CU3. lékařská fakultaThird Faculty of Medicin

    Beyond Quantity: Research with Subsymbolic AI

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    How do artificial neural networks and other forms of artificial intelligence interfere with methods and practices in the sciences? Which interdisciplinary epistemological challenges arise when we think about the use of AI beyond its dependency on big data? Not only the natural sciences, but also the social sciences and the humanities seem to be increasingly affected by current approaches of subsymbolic AI, which master problems of quality (fuzziness, uncertainty) in a hitherto unknown way. But what are the conditions, implications, and effects of these (potential) epistemic transformations and how must research on AI be configured to address them adequately

    Cultivate Quantitative Magnetic Resonance Imaging Methods to Measure Markers of Health and Translate to Large Scale Cohort Studies

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    Magnetic Resonance Imaging (MRI) is an indispensable tool in healthcare and research, with a growing demand for its services. The appeal of MRI stems from its non-ionizing radiation nature, ability to generate high-resolution images of internal organs and structures without invasive procedures, and capacity to provide quantitative assessments of tissue properties such as ectopic fat, body composition, and organ volume. All without long term side effects. Nine published papers are submitted which show the cultivation of quantitative measures of ectopic fat within the liver and pancreas using MRI, and the process of validating whole-body composition and organ volume measurements. All these techniques have been translated into large-scale studies to improve health measurements in large population cohorts. Translating this work into large-scale studies, including the use of artificial intelligence, is included. Additionally, an evaluation accompanies these published studies, appraising the evolution of these quantitative MRI techniques from the conception to their application in large cohort studies. Finally, this appraisal provides a summary of future work on crowdsourcing of ground truth training data to facilitate its use in wider applications of artificial intelligence.In conclusion, this body of work presents a portfolio of evidence to fulfil the requirements of a PhD by published works at the University of Salford

    Extracting heart rate dependent electrocardiogram templates for a body emulator environment

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    Abstract. Medical device and analysis method developments often include tests on humans, which are expensive, time consuming, and sometimes even dangerous. In order to perform human tests, special safety conditions and ethical and legal requirements must be taken into account. Emulators that can emulate the physiological functions of the human body could solve these difficulties. In this study, the heart rate depended electrocardiogram templates for this kind of an emulator were extracted. The real-life electrocardiogram preprocessing included a high-pass filter and a Savitzky-Golay filter. A beat detection algorithm was developed to detect QRS complexes in the signals and classify beat artefacts based on the RR interval sequences and two adaptive thresholds. Heart rate levels were detected using the K-means clustering technique. Vectorcardiogram signals were converted from the electrocardiogram signals using the inverse Dower’s transformation matrix, and vectorcardiogram templates were extracted to the respective heart rate levels. Finally, a graphical user interface was created for the mentioned methods. The developed beat detection algorithm was tested with the MIT-BIH Arrhythmia Database and the comparison was made with the state-of-the-art algorithms. The beat detection algorithm resulted the sensitivity of 99.77 \%, precision of 99.65 \%, and detection error rate of 0.58 \%. Based on the results, the proposed methods and extracted vectorcardiogram templates were successful.Sykkeestä riippuvien elektrokardiogrammimallien poiminta kehoemulaattoriympäristöön. Tiivistelmä. Lääketieteellisten laitteiden ja analyysimenetelmien kehitystyö sisältää usein ihmisille suoritettavia testejä, jotka ovat kalliita, aikaa vieviä ja joskus jopa vaarallisia. Ihmiskokeiden toteuttamiseksi on otettava huomioon erityisiä turvallisuusehtoja, sekä eettisiä ja laillisia vaatimuksia. Emulaattorit, jotka pystyvät jäljittelemään ihmiskehon fysiologisia toimintoja, voivat olla ratkaisu näihin ongelmiin. Tässä tutkimuksessa sykkeestä riippuvia elektrokardiogrammimalleja poimittiin tämän tyyppiselle emulaattorille. Tosielämän elektrokardiogrammisignaalien esikäsittely sisälsi ylipäästösuodattimen ja Savitzky-Golay suodattimen. Sydämen lyöntien tunnistussalgoritmi kehitettiin tunnistamaan QRS-komplekseja signaaleista ja luokittelemaan lyöntiartefakteja RR-intervallisekvenssien ja kahden adaptiivisen kynnysarvon perusteella. Syketasot tunnistettiin käyttämällä K-means klusterointitekniikkaa. Vektorikardiogrammisignaalit muunnettiin elektrokardiogrammisignaaleista käyttämällä käänteistä Dowerin muunnosmatriisia ja vektorikardiogrammimallit poimittiin vastaaville syketasoille. Lopuksi luotiin graafnen käyttöliittymä mainituille menetelmille. Kehitetty lyöntien tunnistusalgoritmi testattiin MIT-BIH Arrhythmia Database-tietokannalla ja vertailu suoritettiin vastaavien algoritmien kanssa. Algoritmi suoriutui 99,77 % herkkyydellä, 99,65 % spesifsyydellä ja 0,58 % virheprosentilla. Tulosten perusteella ehdotetut menetelmät ja poimitut vektorikardiogrammimallit olivat onnistuneita
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