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open access

Existence of an Alpha One-Adrenoceptor-Mediated Coronary Vasoconstrictor Reflex During Acute Systemic Hypoxia, in Anesthetized, Open-Chest Dogs

Description: The presence of an alpha-adrenoceptor--mediated coronary vasoconstrictor reflex during acute systemic hypoxia was examined in thirteen chloralose-anesthetized dogs. Local vasodilator effects were avoided by perfusing the left common coronary artery (LCC) with normoxic blood, while the dogs were ventilated with 5% 02-95% N2 . Left ventricular afterload was held constant and positive cardiac inotropic responses and beta two-adrenoceptor-mediated coronary vasodilation were blocked by propranolol. … more
Date: December 1987
Creator: Grice, Derald Preston
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Model for Determining Induced Physiological Stress During Respirator Wear

Description: A model was developed to predict the increased physiological effort of wearing a respiratory protective device. Specifically, the model was designed to predict the effects of varying ventilatory demands on eleven respiratory variables of the man-respirator system, breath frequency (f_b), tidal volume (V_t), inspiratory flow (dvi/dt), expiratory flow (dve/dt), inspiratory mask pressure (P_mi), expiratory mask pressure (P_me), inspiratory intrathoracic pressure (P_ii), expiratory intrathoracic pr… more
Date: December 1984
Creator: Meyer, Steve D. (Steve Douglas)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Adenosine Antagonist Aminophylline Attenuates Pacing-Induced Coronary Functional Hyperemia

Description: Left coronary blood flow (LCBF), left ventricular oxygen, extraction [(a-v)O₂ ], and myocardial oxygen consumption (MVO₂) were monitored in 10 dogs. HR was paced at 120 bpm and then increased to 180 bpm to elicit a hyperemic response (ΔLCBF). During the hyperemia, the vaso-dilatory response to exogenous adenosine (F_AD) was tested. Twenty min. after injection of aminophylline (100 mg/i.v.), HR was again increased. F_AD was again tested. The pacing-induced increase in MVO₂ (ΔMVO₂) was not affect… more
Date: December 1984
Creator: Randall, John Robert
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Alpha-Adrenergic Modulation of Coronary Blood Flow and Cardiac Function During Exercise in Dogs

Description: In the present study alpha-receptor modulation of coronary flow and cardiac function was examined in exercising dogs, chronically instrumented to measure: circumflex blood flow velocity (CFV), heart rate (HR), global left ventricular function (LVP and dP/dt Max) and regional left ventricular function (%SL and dL/dt (s)max). During exercise, local adrenergic blockade was produced by intracoronary injection of 1.0 mg phentolamine ( anon-specific alpha-antagonist) or .5 mp prazosin. Exercise sign… more
Date: December 1985
Creator: Overn, Steven P. (Steven Paul)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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