ABSTRACT
Thirty obese women were randomly assigned to either 40% [severe energy restriction (SER)] or 70% [moderate energy restriction (MER)] of their maintenance energy requirements and to no exercise, aerobic exercise (walking), or aerobic exercise plus circuit weight training. Body composition by hydrostatic weighing and energy expenditure by indirect calorimetry were measured at 0, 3, and 6 mo. In addition, we developed a deficit-efficiency factor (DEF), calculated as body energy loss/dietary energy deficit, to attempt to quantify the effectiveness of the weight-reduction interventions. Subjects in the SER group lost more weight (mean +/- SE: 15.1 +/- 1.4 vs 10.8 +/- 1.0 kg), fat (11.7 +/- 1.1 vs 8.3 +/- 0.6 kg), and fat-free mass (2.8 +/- 0.3 vs 1.8 +/- 0.3 kg) than the MER group (P < or = 0.05). However, the overall DEF was greatest in the MER group (0.80 +/- 0.07) compared with the SER group (0.52 +/- 0.05; P < or = 0.01). Exercise had no significant effect. This study demonstrates that MER may offer an advantage over SER because it produces a greater energy loss relative to energy deficit.
Subject(s)
Diet, Reducing , Energy Intake , Exercise , Obesity/therapy , Weight Loss , Adult , Basal Metabolism , Body Composition , Calorimetry, Indirect , Energy Metabolism , Female , Humans , Nitrogen/metabolism , Obesity/diet therapyABSTRACT
This study characterizes the electrophysiologic effects of the alpha agonist phenylephrine on the rabbit sinus node. Phenylephrine increased sinus node firing rate and increased slope of Phase 4 depolarization. It shortened action potential duration. It had no effect on maximum diastolic potential or action potential amplitude. These actions were blocked by propranolol. These data imply phenylephrine may exert an effect on the sinus node through a beta-adrenoreceptor.
Subject(s)
Phenylephrine/pharmacology , Receptors, Adrenergic, alpha/drug effects , Sinoatrial Node/physiology , Action Potentials/drug effects , Animals , Female , In Vitro Techniques , Male , Perfusion , Propranolol/pharmacology , Rabbits , Sinoatrial Node/drug effectsABSTRACT
The anti-inflammatory agent indomethacin has been shown to affect calcium in smooth muscle, cardiac muscle, and cardiac Purkinje cells. This study looked at the action of indomethacin on rabbit sinus node. High doses of indomethacin reduce the slope of diastolic depolarization, spontaneous rate, action potential amplitude and time of repolarization. These results are consistent with a reduction of inward transmembrane movement of calcium.
