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T McCalden

Publications and source records attributed to T McCalden.

6 recordsLinked to original sources
PubMed1996

Induced hypertension during ischemia reduces infarct area after temporary middle cerebral artery occlusion in rats.

BACKGROUND: Induced hypertension is one of the few interventions available to reverse acute ischemic neurologic deficit. The purpose of this study was to determine the safety and efficacy of hypertension during prolonged temporary focal ischemia. METHODS: Anesthetized rats underwent 2 hours of endovascular middle cerebral artery occlusion. Angiotensin was given to increase mean arterial blood pressure to 40%-60% above baseline during ischemia. Neurologic deficit and infarct size in hypertensive rats were assessed at 72 hours. RESULTS: Hypertensive rats had smaller infarcts than normotensive controls (mean, 12.40 +/- 3.71% versus 24.19 +/- 2.89; p < 0.05) without hemorrhage. Neuroscores were comparable. CONCLUSION: Hypertension safely reduces infarction after 2 hours of focal ischemia in rats.

Angiotensin II↗
PubMed1984

Analysis of the asymmetric response of the rabbit ear artery to intimal and adventitial amines.

Ring segments of the rabbit ear artery were studied in the normal configuration (where drugs entered the media mainly through the adventitia) and in the everted configuration (where drugs entered mainly through the intima). Norepinephrine (NE) produced a faster response when added to the intima. This difference was not due to NE uptake mechanisms or asymmetry of different types of alpha-receptor. However, tetraethylammonium chloride (which abolishes rectification and increases membrane electrical activity) selectively increased the velocity of contraction of the normal artery segments to NE. These results suggest that approximately 50% of the difference between the intimal and adventitial velocity of contraction to NE is due to the presence of an intimal electromechanical coupling mechanism which does not operate at the adventitia. The remaining difference may be due to a closer proximity of medial alpha-receptor to the intimal surface.

Animals↗