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Total 656 results found since Jan 2013.
Autoregulation of cardiac output is overcome by adrenergic stimulation in the anaconda heart SHORT COMMUNICATION
William Joyce, Michael Axelsson, and Tobias Wang Most vertebrates increase cardiac output during activity by elevating heart rate with relatively stable stroke volume. However, several studies have demonstrated ‘intrinsic autoregulation’ of cardiac output where artificially increased heart rate is associated with decreased stroke volume, leaving cardiac output unchanged. We explored the capacity of noradrenaline to overcome autoregulation in the anaconda heart. Electrically pacing in situ perfused hearts from the intrinsic heart rate to the maximum attainable resulted in a proportional decrease in stroke volume...
Source: Journal of Experimental Biology - November 9, 2016 Category: Biology Authors: Joyce, W., Axelsson, M., Wang, T. Tags: SHORT COMMUNICATION Source Type: research
Basic properties of ATP-induced myosin head movement in hydrated myosin filaments, studied using the gas environmental chamber
Publication date: September 2018 Source:Micron, Volume 112 Author(s): H. Sugi, T. Akimoto, S. Chaen Although more than 50 years have passed since the monumental discovery of Huxley and Hanson that muscle contraction results from relative sliding between actin and myosin filaments, coupled with ATP hydrolysis, the mechanism underlying the filament sliding still remains to be a mystery. It is generally believed that the myofilament sliding is caused by cyclic attachment-detachment between myosin heads in myosin filaments and myosin-binding sites in actin filaments. Attempts to prove the myosin head movement using techniques...
Source: Micron - June 20, 2018 Category: Biology Source Type: research
How the hummingbird wingbeat is tuned for efficient hovering RESEARCH ARTICLE
Rivers Ingersoll and David Lentink
Both hummingbirds and insects flap their wings to hover. Some insects, like fruit flies, improve efficiency by lifting their body weight equally over the upstroke and downstroke, while utilizing elastic recoil during stroke reversal. It is unclear whether hummingbirds converged on a similar elastic storage solution, because of asymmetries in their lift generation and specialized flight muscle apparatus. The muscles are activated a quarter of a stroke earlier than in larger birds, and contract superfast, which cannot be explained by previous stroke-averaged analyses. We measured the aerod...
Source: Journal of Experimental Biology - October 15, 2018 Category: Biology Authors: Ingersoll, R., Lentink, D. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research
MiR-145 protected the cell viability of human cerebral cortical neurons after oxygen-glucose deprivation by downregulating EPHA4
In this study, we aimed to further explore their function in a model of oxygen-glucose deprivation (OGD). The expression of miR-145 in the blood of 44 patients with ischemic stroke and 37 normal controls was detected by qRT-PCR. After transfection with either the wild- or mutant-type pGL3-promoter EPHA4 3′UTR into the miR-145 mimic and miR-145 inhibitor, a dual-luciferase reporter assay was performed to explore the interaction between miR-145 and EPHA4. qRT-PCR and Western blot were performed to further explore the effects of miR-145 on EPHA4 expression after an miR-145 mimic, an miR-145 inhibitor or LV-sh-EPHA4 was tran...
Source: Life Sciences - May 29, 2019 Category: Biology Source Type: research
Novel mechanistic insight on the neuroprotective effect of berberine: The role of PPAR δ for antioxidant action
Free Radic Biol Med. 2022 Jan 27:S0891-5849(22)00033-8. doi: 10.1016/j.freeradbiomed.2022.01.022. Online ahead of print.ABSTRACTCerebral ischemic stroke ranks the second leading cause of death and the third leading cause of disability in lifetime all around the world, urgently necessitating effective therapeutic interventions. Reactive oxygen species (ROS) have been implicated in stroke pathogenesis and peroxisome proliferator-activated receptors (PPARs) are prominent targets for ROS management. Although recent research has shown antioxidant effect of berberine (BBR), little is known regarding its effect upon ROS-PPARs sig...
Source: Free Radical Biology and Medicine - January 30, 2022 Category: Biology Authors: Jia-Wen Shou Xiao-Xiao Li Yun-Sang Tang Bobby Lim-Ho Kong Hoi-Yan Wu Meng-Jie Xiao Chun-Kai Cheung Pang-Chui Shaw Source Type: research
Depletion of iNOS-positive inflammatory cells decelerates neuronal degeneration and alleviates cerebral ischemic damage by suppressing the inflammatory response
Free Radic Biol Med. 2022 Feb 9:S0891-5849(22)00061-2. doi: 10.1016/j.freeradbiomed.2022.02.008. Online ahead of print.ABSTRACTIschemic stroke leads to neuronal damage and severe inflammation that activate iNOS expression in different cell types, especially inflammatory cells in the brain. It is shown that NO released from iNOS contributes to the pathological development of cerebral ischemia. However, the role of these iNOS-expressing inflammatory cells in ischemic stroke has not been fully elucidated. Our purpose is to test if ischemia-induced iNOS+ inflammatory cells may exaggerate cerebral inflammation to exacerbate neu...
Source: Free Radical Biology and Medicine - February 12, 2022 Category: Biology Authors: Ting Li Ting Xu Jin Zhao Hao Gao Wenguang Xie Source Type: research
Multiscale effects of excitatory-inhibitory homeostasis in lesioned cortical networks: A computational study
We present a large-scale model of the neocortex, with synaptic scaling of local inhibition, showing how E-I homeostasis can drive the post-lesion restoration of FC and linking it to changes in excitability. We show that functional networks could reorganize to recover disrupted modularity and small-worldness, but not network dynamics, suggesting the need to consider forms of plasticity beyond synaptic scaling of inhibition. On average, we observed widespread increases in excitability, with the emergence of complex lesion-dependent patterns related to biomarkers of relevant side effects of stroke, such as epilepsy, depressio...
Source: PLoS Computational Biology - July 7, 2023 Category: Biology Authors: Francisco P áscoa dos Santos Source Type: research
Overexpression of Circ_0005585 Alleviates Cerebral Ischemia Reperfusion Injury via Targeting MiR-16-5p
Circular RNAs are implicated in the pathogenesis of ischemic stroke. In this work, we explored the modulation and potential mechanisms of action of circ_0005585 in ischemic stroke. Expression of circ_0005585 and miR-16-5p was assessed by quantitative real-time reverse transcription PCR. Ischemic stroke was modeled in mice by middle cerebral artery occlusion (MCAO). The infarct volume was assessed by triphenyl tetrazolium chloride staining. Neurological deficits were evaluated according to Neurological Severity Score. The permeability of the blood —brain barrier was assessed by Evan’s blue leakage and brain water conten...
Source: Bulletin of Experimental Biology and Medicine - August 11, 2023 Category: Biology Source Type: research
Nitrone-based Therapeutics for Neurodegenerative Diseases. Their use alone or in Combination with Lanthionines.
Abstract
The possibility of free radical reactions occurring in biological processes led to the development and employment of novel methods and techniques focused on determining their existence and importance in normal and pathological conditions. For this reason the use of Nitrones for spin trapping free radicals came into widespread use in the 1970s and 1980s when surprisingly the first evidence of their potent biological properties was first noted. Since then wide-spread exploration and demonstration of the potent biological properties of phenyl-tert-butylnitrone (PBN) and derivatives were shown in preclinical ...
Source: Free Radical Biology and Medicine - February 15, 2013 Category: Biology Authors: Floyd RA, Castro Faria Neto HC, Zimmerman GA, Hensley K, Towner RA Tags: Free Radic Biol Med Source Type: research
Cardiovascular effects of levosimendan during rewarming from hypothermia in rat.
CONCLUSION: The present data shows that levosimendan ameliorates hypothermia-induced systolic dysfunction by elevating SV during rewarming from 15°C. Inotropic treatment during rewarming from hypothermia in the present rat model is therefore better achieved through calcium sensitizing and PDE3 inhibition, than β-receptor stimulation.
PMID: 25280932 [PubMed - as supplied by publisher]
Source: Cryobiology - September 30, 2014 Category: Biology Authors: Dietrichs ES, Håheim B, Kondratiev T, Sieck GC, Tveita T Tags: Cryobiology Source Type: research
