David M. Regen

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Chamber-stress equations relate wall stresses to pressure and wall dimensions. Such equations play a central role in the analysis and understanding of heart-chamber function. Over the past three decades, several stress equations giving radically different results have been derived, used, and/or espoused. They can be classified into two categories, according(More)
  • D M Regen
  • The American journal of physiology
  • 1989
It is generally agreed that systolic performance of a heart chamber is the fractional inward displacement of its wall during contraction and that this depends on preload, afterload, and characteristics of the relation between afterload and end-ejection dimensions. However, there is no consensus on the details of this statement. How can one define and(More)
The left ventricle of the heart is a thick-walled chamber. In such a chamber, cavity dimensions do not express overall wall stretch, so fractional cavity-surface displacements are not ideal performance expressions, and the intercepts and slopes of relations between intensive variables (pressure, stress, resistance, viscosity) and cavity dimensions do not(More)
An increase in early rates of oleate uptake, which reflected fatty acid (FA) entry into the cells, was apparent 2-3 days after confluence of differentiating BFC-1 preadipocytes. The increase was measured in cells kept without glucose and with arsenate, where greater than 95% of intracellular radioactivity was recovered as free unesterified oleate. Uptake of(More)
Kinetic characteristics of glucose transport and glucose phosphorylation were studied in the islet cell line beta TC-1 to explore the roles of these processes in determining the dependence of glucose metabolism and insulin secretion on external glucose. The predominant glucose transporter present was the rat brain/erythrocyte type (Glut1), as determined by(More)
Glucose transport in the rat erythrocyte is subject to feedback regulation by sugar metabolism at high but not at low temperatures [Abumrad et al. (1988) Biochim. Biophys. Acta 938, 222-230]. This indicates that temperature, which is known to alter membrane fluidity, also alters sensitivity of transport to regulation. In the present work, we have(More)
There are occasions in physiological research and medical practice where it is desirable to estimate the average fiberstress in a chamber wall, knowing only the pressure and dimensions. Because the contribution of a strained wall element to pressure depends on its location whereas its contribution to average stress is independent of location, an equation of(More)
A heart chamber undergoes eccentric hypertrophy in response to a chronic elevation of stroke-displacement demand, and it undergoes concentric hypertrophy in response to a chronic elevation of systolic-pressure demand. Both of these adaptations, which occur in various combinations, involve two myocardial plastic properties, "stretch normalization" and(More)
The initial events in glucose metabolism by all cells are the transport and phosphorylation of glucose. To quantify the relative contributions of these two processes to overall glucose utilization, we have developed an experimental approach for their in situ measurement as parallel processes. The method is based on the use of intracellular [2-3H]glucose as(More)