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As we approach the centenary of the term "comparative physiology," we reexamine its role in modern biology. Finding inspiration in Krogh's classic 1929 paper, we first look back to some timeless contributions to the field. The obvious and fascinating variation among animals is much more evident than is their shared physiological unity, which transcends both body size and specific adaptations. The "unity in diversity" reveals general patterns and principles of physiology that are invisible when examining only one species. Next, we examine selected contemporary contributions to comparative physiology, which provides the context in which reductionist experiments are best interpreted. We discuss the sometimes surprising insights provided by two comparative "athletes" (pronghorn and rattlesnakes), which demonstrate 1) animals are not isolated molecular mechanisms but highly integrated physiological machines, a single "rate-limiting" step may be exceptional; and 2) extremes in nature are rarely the result of novel mechanisms, but rather employ existing solutions in novel ways. Furthermore, rattlesnake tailshaker muscle effectively abolished the conventional view of incompatibility of simultaneous sustained anaerobic glycolysis and oxidative ATP production. We end this review by looking forward, much as Krogh did, to suggest that a comparative approach may best lend insights in unraveling how skeletal muscle stores and recovers mechanical energy when operating cyclically. We discuss and speculate on the role of the largest known protein, titin (the third muscle filament), as a dynamic spring capable of storing and recovering elastic recoil potential energy in skeletal muscle. [ABSTRACT FROM AUTHOR]

BACKGROUND: A previous study of healthy subjects showed that intake of 6 g cinnamon with rice pudding reduced postprandial blood glucose and the gastric emptying rate (GER) without affecting satiety. OBJECTIVE: The objective was to study the effect of 1 and 3 g cinnamon on GER, postprandial blood glucose, plasma concentrations of insulin and incretin hormones [glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1)], the ghrelin response, and satiety in healthy subjects. DESIGN: GER was measured by using real-time ultrasonography after ingestion of rice pudding with and without 1 or 3 g cinnamon. Fifteen healthy subjects were assessed in a crossover trial. RESULTS: The addition of 1 or 3 g cinnamon had no significant effect on GER, satiety, glucose, GIP, or the ghrelin response. The insulin response at 60 min and the area under the curve (AUC) at 120 min were significantly lower after ingestion of rice pudding with 3 g cinnamon (P = 0.05 and P = 0.036, respectively, after Bonferroni correction). The change in GLP-1 response (DeltaAUC) and the change in the maximum concentration (DeltaC(max)) were both significantly higher after ingestion of rice pudding with 3 g cinnamon (P = 0.0082 and P = 0.0138, respectively, after Bonferroni correction). CONCLUSIONS: Ingestion of 3 g cinnamon reduced postprandial serum insulin and increased GLP-1 concentrations without significantly affecting blood glucose, GIP, the ghrelin concentration, satiety, or GER in healthy subjects. The results indicate a relation between the amount of cinnamon consumed and the decrease in insulin concentration. Copyright © 2009 American Society for Nutrition [ABSTRACT FROM AUTHOR]

Previous research has shown -125 mmHg to be the optimal negative pressure for creating an environment that promotes wound healing, and this has therefore been adopted as a standard pressure for patients with deep sternal wound infection. However, it has not yet been clearly shown that -125 mmHg is the optimal pressure from a haemodynamic point of view. Furthermore, there have been reports of cardiac rupture during -125 mmHg negative pressure therapy. We therefore studied the effects of a lower pressure: -75 mmHg. Twelve pigs were used. After median sternotomy, sealed negative pressure therapy of -75 mmHg was applied. Baseline measurements were made and continuous recording of the cardiac output, end-tidal CO(2) production, mean arterial pressure, mean pulmonary pressure (pulmonary artery pressure), systemic vascular resistance, pulmonary vascular resistance, left atrial pressure and central venous pressure was started. Six pigs served as controls. No statistically significant difference was observed in any of the haemodynamic parameters studied, compared with the controls. The present study shows that, with a suitable foam application technique, -75 mmHg can be applied without compromising the central haemodynamics. [ABSTRACT FROM AUTHOR]

The purpose of this study was to describe an electromyogram (EMG) pattern during a submaximal eccentric task in 7 subjects adapted to high-force chronic eccentric exercise and 6 subjects naive to eccentric exercise. The EMG in all subjects was quantified during identical submaximal (200 W) eccentric and concentric cycle ergometry tasks. The EMG of the eccentrically adapted subjects was decreased (p < 0.05) compared to the eccentrically naive subjects, in duration, amplitude, and intensity as evidenced by a decreased EMG during the pedal cycle. This decrease may be one component of the protective effect that results from progressively increasing repeated bouts of eccentric muscle work. Clients and patients transitioning to rigorous overload training should become adapted to high eccentric loads and forces to avoid injury and a potential delay in their strength and conditioning training regimens. [ABSTRACT FROM AUTHOR]

Monodelphis domestica (Marsupialia: Didelphidae) was used as a model animal to investigate and compare muscle adaptation to exercise training and cold exposure. The experimental treatment consisted of four groups of animals: either warm or cold acclimation temperature and with or without endurance exercisetraining. Maximal aerobic capacity during a running Vo2max test in the warm-exercised or cold-exposed (with or without without exercise) groups was about 130 mL O2/kg/min, significantlyhigher than the warm-acclimated controls at 113.5mL O2/kg/min. Similarly, during an acute cold challenge (Vo2summit ), maximal aerobic capacity was higher in these three experimental groups at ∼95 mL O2/kg/min compared with 80.4mL O2/kg/min in warm-acclimated controls. Respiratory exchange ratio was significantly lower (0.89-0.68), whereas relative heart mass 0.52%-0.73%) and whole-body muscle mitochondrialvolume density (2.59 to 3.04 cm[sup3]) were significantly higher following cold exposure. Chronic cold exposure was a stronger stimulus than endurance exercise training for tissue specific adaptations. Although chronic cold exposure and enduranceexercise are distinct challenges, physiological adaptations to each overlap such that the capacities for aerobic performance in response to both cold exposure and running are increased by either or both treatments. [ABSTRACT FROM AUTHOR]

One challenge for veterinarians, animal facilities and research scientists is the making of physiological estimates appropriate to a variety of species for which data are often either completely lacking or are incomplete. Our intent in compiling the data in this paper is to provide the best possible database of normal physiological and anatomical values primarily (though not exclusively) for four common mammalian model species: mouse, rat, dog and man. In order to make those data as accessible and applicable as possible, we have presented the results of this study in the form of body-size dependent allometric equations in which some variable (Y) is expressed as a dependent function of body mass (M) in the power-law equation, Y =aMb. By compiling these data, it is apparent that the resultant equations are quantitatively grouped (with similar slope or 'b' values). These emergent patterns provide insights into body-size dependent 'principles of design' that seem to dictate several aspects of design and function across species among all mammals. In general, the weights of most individual organs scale as a constant fraction of body mass (i.e. the body mass exponent, b ≅ 1.0). Biological rates (e.g. heart rate, respiratory rate) scale as b ≅ -1/4. Finally, volume-rates (the product of volume and rate) such as cardiac output, ventilation and oxygen uptake vary as b ≅ 3/4. [ABSTRACT FROM AUTHOR]

Provides information on a study which examined the impact of chronic eccentric training on the spring properties of skeletal muscle. Methods; Results and discussion.