Biomedical subjects
C H Edwards
Publications and source records attributed to C H Edwards.
Regional diastolic mechanics of the left ventricle in the conscious dog.
In eight chronically instrumented conscious dogs, apical and middle left ventricular transverse diameters were measured with pulse-transit ultrasonic dimension transducers. Intracavitary apical and midventricular pressures and intrapleural pressure were measured with micromanometers. Both diameters were normalized as a percent extension from the dimension at zero transmural pressure, determined during a transient vena caval occlusion. During the rapid phase of diastolic filling, there was a 2--5 mmHg pressure gradient from the midventricle to the apex. During late rapid filling, the apical transmural pressure and diameter increased more rapidly and reached diastasis 17 +/- 4 ms earlier than the corresponding midventricular measurements (P less than 0.01). The static diastolic pressure-dimension characteristics at the apical and midventricular levels were not significantly different (P greater than 0.30). The dynamic diastolic pressure-dimension relationship was also similar at the two levels and could be represented by a model incorporating parallel viscous properties. Because of regional differences in pressures and dimensions, however, the dynamic relationship could not be modeled when pressure was compared to the dimension at a different level. Thus, diastolic pressures should be measured at the same level as dimensions when assessing left ventricular diastolic mechanics.
Formation of methionine from alpha-amino-n-butyric acid and 5'-methylthioadenosine in the rat.
Adult rats may utilize two metabolites of methionine for the biosynthesis of this essential amino acid. In separate experiments methionine, labeled with 14C or with 35S was observed in plasma and urine following the administration of [2-14C]-alpha-amino-n-butyric acid or [35S]-5'-methylthioadenosine by stomach tube. Although alpha-amino-n-butyric acid (ABA) or homoserine, alone or with dietary sodium sulfate, choline, and/or S-methylcysteine, was not utilized for growth, weight loss in weanling rats was decreased by dietary cysteine when fed as an additive to a basal methionine-free, cysteine-free, labile methyl-free, sulfur-free diet. Following the addition of 10 mg ABA and 28 mg 5'-methylthioadenosine/day to the basal diet, growth response was equivalent to that occurring in rats receiving 27 mg of methionine/day with the basal diet. The implications of these findings for adaptation to protein restriction and a discussion of equilibrium and steady state conditions related to the increase in methionine content in the blood are presented.
Effect of left ventricular hypertrophy on myocardial capillary perfusion.
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Effects of ischemia on left ventricular regional function in conscious dogs.
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Utilization of wheat by adult man: excretion of vitamins and minerals.
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