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Blackwood, Sarah J
Publications (2 of 2) Show all publications
Premilovac, D., Blackwood, S. J., Ramsay, C. J., Keske, M. A., Howells, D. W. & Sutherland, B. A. (2020). Transcranial contrast-enhanced ultrasound in the rat brain reveals substantial hyperperfusion acutely post-stroke.. Journal of Cerebral Blood Flow and Metabolism, 40(5), 939-953, Article ID 271678X20905493.
Open this publication in new window or tab >>Transcranial contrast-enhanced ultrasound in the rat brain reveals substantial hyperperfusion acutely post-stroke.
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2020 (English)In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 40, no 5, p. 939-953, article id 271678X20905493Article in journal (Refereed) Published
Abstract [en]

Direct and real-time assessment of cerebral hemodynamics is key to improving our understanding of cerebral blood flow regulation in health and disease states such as stroke. While a number of sophisticated imaging platforms enable assessment of cerebral perfusion, most are limited either spatially or temporally. Here, we applied transcranial contrast-enhanced ultrasound (CEU) to measure cerebral perfusion in real-time through the intact rat skull before, during and after ischemic stroke, induced by intraluminal filament middle cerebral artery occlusion (MCAO). We demonstrate expected decreases in cortical and striatal blood volume, flow velocity and perfusion during MCAO. After filament retraction, blood volume and perfusion increased two-fold above baseline, indicative of acute hyperperfusion. Adjacent brain regions to the ischemic area and the contralateral hemisphere had increased blood volume during MCAO. We assessed our data using wavelet analysis to demonstrate striking vasomotion changes in the ischemic and contralateral cortices during MCAO and reperfusion. In conclusion, we demonstrate the application of CEU for real-time assessment of cerebral hemodynamics and show that the ischemic regions exhibit striking hyperemia post-MCAO. Whether this post-stoke hyperperfusion is sustained long-term and contributes to stroke severity is not known.

Place, publisher, year, edition, pages
Sage Publications, 2020
Keywords
Ischemic stroke, cerebral blood flow, contrast-enhanced ultrasound, middle cerebral artery occlusion, rat
National Category
Neurology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-6045 (URN)10.1177/0271678X20905493 (DOI)000514038400001 ()32063081 (PubMedID)
Available from: 2020-02-24 Created: 2020-02-24 Last updated: 2020-05-29Bibliographically approved
Blackwood, S. J. & Katz, A. (2019). Isoproterenol enhances force production in mouse glycolytic and oxidative muscle via separate mechanisms.. Pflügers Archiv: European Journal of Physiology, 471(10), 1305-1316
Open this publication in new window or tab >>Isoproterenol enhances force production in mouse glycolytic and oxidative muscle via separate mechanisms.
2019 (English)In: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 471, no 10, p. 1305-1316Article in journal (Refereed) Published
Abstract [en]

Fight or flight is a biologic phenomenon that involves activation of β-adrenoceptors in skeletal muscle. However, how force generation is enhanced through adrenergic activation in different muscle types is not fully understood. We studied the effects of isoproterenol (ISO, β-receptor agonist) on force generation and energy metabolism in isolated mouse soleus (SOL, oxidative) and extensor digitorum longus (EDL, glycolytic) muscles. Muscles were stimulated with isometric tetanic contractions and analyzed for metabolites and phosphorylase activity. Under conditions of maximal force production, ISO enhanced force generation markedly more in SOL (22%) than in EDL (8%). Similarly, during a prolonged tetanic contraction (30 s for SOL and 10 s for EDL), ISO-enhanced the force × time integral more in SOL (25%) than in EDL (3%). ISO induced marked activation of phosphorylase in both muscles in the basal state, which was associated with glycogenolysis (less in SOL than in EDL), and in EDL only, a significant decrease (16%) in inorganic phosphate (Pi). ATP turnover during sustained contractions (1 s EDL, 5 s SOL) was not affected by ISO in EDL, but essentially doubled in SOL. Under conditions of maximal stimulation, ISO has a minor effect on force generation in EDL that is associated with a decrease in Pi, whereas ISO has a marked effect on force generation in SOL that is associated with an increase in ATP turnover. Thus, phosphorylase functions as a phosphate trap in ISO-mediated force enhancement in EDL and as a catalyzer of ATP supply in SOL.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Fatigue, Force, Isoproterenol, Metabolites, Muscle, Phosphorylase
National Category
Physiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5835 (URN)10.1007/s00424-019-02304-0 (DOI)000492593900006 ()31451903 (PubMedID)
Available from: 2019-09-16 Created: 2019-09-16 Last updated: 2019-12-19
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