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Biomedical subjects

I Hutton

Publications and source records attributed to I Hutton.

108 records · Page 6Linked to original sources
PubMed1975

Reduced myocardial reflow and increased coronary vascular resistance following prolonged myocardial ischemia in the dog.

Studies were performed to determine whether an alteration in coronary vascular resistance and a reduction in the reflow phenomenon occurred in the blood-perfused, heparinized canine heart after various periods of myocaridal ischemia. Regional myocardial blood flow was measured with radioactive microspheres. Proximal left anterior descending coronary artery blood flow was measured with a periarterial flow transducer. Reduced reflow to the ischemic portion of the left ventricle and increased resistance in the left anterior descending coronary artery were present after 120 minutes of myocardial ischemia. The reduction in reflow was specific to the subendocardium of the ischemic area. Saline and isosorbide dinitrate (Isordi) did not prevent the increase in coronary vascular resistance or the significant reduction in reflow to the subendocardial portion of the ischemic area. Hypertonic mannitol given so as to increase serum osmolality 40 mosmoles/kg prevented the increase in coronary vascular resistance and modified the reduction in the reflow phenomenon to the subendocardial portion of the ischemic area. Thus, both an increase in coronary vascular resistance and a significant reduction in reflow to the subendocardial portion of the ischemic area occur in the canine heart after 120 minutes of myocardial ischemia. Moreover, the increase in coronary vascular resistance can be prevented and the reduction in reflow to the subendocardial portion of the ischemic area can be modified by the administration of hypertonic mannitol.

Animals↗
PubMed1975

The influence of hypertonic mannitol on regional myocardial blood flow during acute and chronic myocardial ischemia in anesthetized and awake intact dogs.

The influence of hypertonic mannitol on regional myocardial blood flow and ventricular performance was studied during acute myocardial ischemia in awake, unsedated and in anesthesized dogs and after myocardial infarction in awake unsedated dogs. Regional myocardial blood flow was measured with radioactive microspheres. Generalized increases in regional myocardial blood flow occurred after mannitol in all of the different animal models studied. The increases in coronary blood flow after mannitol were just as impressive in the nonischemic regions as in the ischemic portion of the left ventricle in all of the different models that were examined in this study. Improvement in regional myocardial blood flow to the ischemic area of the left ventricle after mannitol was associated with a reduction in ST segment elevation during acute myocardial ischemia in anesthetized dogs. The increases in regional myocardial flow after mannitol were also associated with increases in contractility, but the increases in flow appeared to be more impressive than the changes in contractility. The data obtained demonstrate that mannitol increases regional coronary blood flow to both ischemic and nonischemic myocardium in both anesthetized and awake, unsedated, intact dogs with acute and chronic myocardial ischemia and that mannitol reduces ST segment elevation during acute myocardial ischemia in anesthetized dogs. Thus the results suggest that under these circumstances the increases in regional myocardial blood flow after mannitol are of physiological importance in reducing the extent of myocardial injury. Since coronary blood flow increased to nonischemic regions the increases in regional myocardial flow demonstrated in this study after mannitol cannot be entirely explained by the mechanism of reduction in ischemic cell swelling.

Acute Disease↗
PubMed1974

The effects of a new beta-adrenoceptor blocking compound, tolamolol, on haemo-dynamics and myocardial function in man.

1 The effects of tolamolol on haemodynamics and myocardial contractility were investigated in two groups of six patients undergoing diagnostic cardiac catheterization.2 The intravenous administration of tolamolol (0.15 mg/kg) produced a significant fall in heart rate from a control value (87 +/- 7 to 62 +/- 3 beats/min) 5 min after administration and a concomitant fall in cardiac output from 4.7 +/- 0.9 to 3.5 +/- 0.8 litres/minute. There was no significant change in systemic blood pressure, pulmonary artery blood pressure or stroke volume.3 There was no change in left ventricular end diastolic pressure after tolamolol. There was a fall in the maximum rate of rise of the left ventricular pressure (LV dp/dt(max)) and the derived index of the left ventricular contractile state (V(max)).4 These results suggest that tolamolol has a predominantly negative chronotropic but also a lesser negative inotropic action on the heart.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Nuclear cardiology.

Nuclear cardiology techniques allow non-invasive assessment of myocardial perfusion and ventricular function. They have a major role in the diagnosis of coronary artery disease, in risk stratification of patients with the disease, in the determination of myocardial viability, and in the evaluation of the functional impact of known coronary artery lesions.

Coronary Disease↗