In an experimental model of adult respiratory distress syndrome (ARDS) we have investigated the release of several vasoactive mediators since the rapid and severe increase in pulmonary arterial pressure is known to be a key feature in this condition. Intravenous injection of oleic acid (OA) into rats resulted in the development of a syndrome similar to ARDS characterized by severe hypoxia. As early as 15 min after OA injection elevated levels of 11-deoxy-15-keto-13,14-dihydro-11,16-cyclo-prostaglandin (PG) E2 (DKH2-cyclo-PGE2) as an indicator of endogenous PGE2 formation could be observed. Similarly, elevated levels of cysteinyl-leukotrienes (LT), determined as immunoreactive (ir) LTE4, and ir-endothelin (ET) could be detected. These mediators were found to be elevated in plasma samples for at least 3 h. In addition, rather large amounts of ir-ET could be detected in bronchoalveolar lavage (BAL) fluid samples between 1 h and 3 h. Thus, it seems possible that cysteinyl-LT and peptides of the ET family, both known for their vasoactivity, might be involved in the pathophysiological process of ARDS.
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http://dx.doi.org/10.1007/978-3-0348-7262-1_6 | DOI Listing |
Biomed Phys Eng Express
January 2025
Shandong Normal University, Jinan, Jinan, Shandong, 250014, CHINA.
In the medical field, endoscopic video analysis is crucial for disease diagnosis and minimally invasive surgery. The Endoscopic Foundation Models (Endo- FM) utilize large-scale self-supervised pre-training on endoscopic video data and leverage video transformer models to capture long-range spatiotemporal dependencies. However, detecting complex lesions such as gastrointestinal metaplasia (GIM) in endoscopic videos remains challenging due to unclear boundaries and indistinct features, and Endo-FM has not demonstrated good performance.
View Article and Find Full Text PDFChaos
January 2025
Physics Institute, University of São Paulo, 05508-090 São Paulo, SP, Brazil.
In this work, we investigate the dynamics of a discrete-time prey-predator model considering a prey reproductive response as a function of the predation risk, with the prey population growth factor governed by two parameters. The system can evolve toward scenarios of mutual or only of predators extinction, or species coexistence. We analytically show all different types of equilibrium points depending on the ranges of growth parameters.
View Article and Find Full Text PDFChaos
January 2025
Agricultural and Ecological Research Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108, India.
Experimental observations and field data demonstrated that predators adapt their hunting strategies in response to prey abundance. While previous studies explored the impact of predation risk on predator-prey interactions, the impact of symbiotic relationships between fear-affected prey and non-prey species on system dynamics remains unexplored. This study uses a mathematical approach to investigate how different symbiotic relationships govern system dynamics when predators adapt to prey availability.
View Article and Find Full Text PDFChaos
January 2025
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Spirals are a special class of excitable waves that have its significance in the understanding of cardiac arrests and neuronal transduction. In a theoretical model of the chemical Belousov-Zhabotinsky reaction system, we explore the dynamics of the spatiotemporal patterns that emerge out of competing reaction and diffusion phenomena. By modifying the existing mathematical models of the reaction kinetics, we have been able to explore the explicit effect of hydrogen ion concentration in the system, so as to achieve various regimes of wave activity, from stable spirals to oscillation death.
View Article and Find Full Text PDFJMIR Form Res
January 2025
Vaccine Study Center, Northern California Division of Research, Kaiser Permanente, Oakland, CA, United States.
Background: Real-world COVID-19 vaccine effectiveness (VE) studies are investigating exposures of increasing complexity accounting for time since vaccination. These studies require methods that adjust for the confounding that arises when morbidities and demographics are associated with vaccination and the risk of outcome events. Methods based on propensity scores (PS) are well-suited to this when the exposure is dichotomous, but present challenges when the exposure is multinomial.
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