Biomedical subjects

Christie Rose-Gottron

Publications and source records attributed to Christie Rose-Gottron.

5 recordsLinked to original sources

PubMed2006

Exercise, caloric restriction, and systemic oxidative stress.

BACKGROUND: In humans, the main sources of reactive oxygen species (ROS), the molecules causing oxidative stress, are mitochondrial superoxide ions and neutrophil-derived oxidative radicals. Circulating antioxidants contribute to the protection against oxidative stress. Although the formation of ROS and secretion of antioxidants are independently regulated by exercise and diet, little is known about their combined effect. We hypothesized that relatively brief, intense exercise training may reduce systemic oxidation via an intrinsic mechanism, independent of changes in circulating antioxidants and of neutrophil-derived enzymes (as may be caused by concomitant caloric restriction). METHODS: Nineteen volunteers exercised for 7 days, 3 hours/day at 75% of oxygen uptake. Caloric intake was either 110% of caloric expenditure (high calorie, n=10) or 75% of caloric expenditure (low calorie, n=9). Blood samples for F2-isoprostanes, catalase, myeloperoxidase (MPO), interleukin-x (IL-x), white blood cells (WBCs), and other metabolic variables were taken at baseline, at the end of training, and 1 week after completion of the study. RESULTS: Serum F2-isoprostanes (microg/mL), markers of lipid peroxidation, were similarly reduced after 7 days of exercise in the high-calorie (from 35+/-4 to 27+/-2) and low-calorie (from 35+/-3 to 24+/-2) groups. Similar reductions were observed in IL-x concentrations. Conversely, no change was observed in circulating concentrations of the antioxidant catalase. Whereas total WBCs and neutrophil counts were significantly reduced in the low-calorie group only, no difference in neutrophil-derived MPO was measured between groups. CONCLUSION: A significant reduction in systemic oxidation may occur relatively early during intense exercise training in healthy young men, independent of caloric intake. The potential contribution to these effects of circulating antioxidants and neutrophil-derived oxidative enzymes will require further investigation.

Adolescent↗

PubMed2005

Breath ethanol and acetone as indicators of serum glucose levels: an initial report.

BACKGROUND: Many volatile organic compounds are present in exhaled breath and may represent by-products of endogenous biological processes. Ethanol is produced via alcoholic fermentation of glucose by gut bacteria and yeast, while acetone derives from oxidations of free fatty acids, influenced by glucose metabolism. We hypothesized that the integrated analysis of breath ethanol and acetone would provide a good approximation of the blood glucose profile during a glucose load. METHODS: We collected simultaneous exhaled breath gas, ambient air, and serum glucose and insulin samples from 10 healthy volunteers at baseline and during an oral glucose tolerance test (OGTT) (ingestion of 75 g of glucose followed by 120 min of sampling). Gas samples were analyzed by gas chromatography/mass spectrometry. RESULTS: Mean glucose values displayed a typical OGTT pattern (rapid increase, peak values at 30-60 min, and gradual return to near baseline by 120 min). Breath ethanol displayed a similar pattern early in the test, with peak values at 30 min; this was followed by a fast return to basal levels by 60 min. Breath acetone decreased progressively below basal levels, with lowest readings obtained at 120 min. A multiple regression analysis of glucose, ethanol, and acetone was used to estimate glucose profiles that correlated with measured glucose values with an average individual correlation coefficient of 0.70, and not lower than 0.41 in any subject. CONCLUSION: The integrated analysis of multiple exhaled gases may serve as a marker of blood glucose levels. Further studies are needed to assess the usefulness of this method in different populations.

Acetone↗

PubMed2004

Cytokines and growth factors during and after a wrestling season in adolescent boys.

PURPOSE: Brief periods of aerobic exercise training lead to reductions, rather then the expected increases in circulating IGF-I. We hypothesized that intense exercise training in adolescents initially leads to simultaneous increases in proinflammatory cytokines and decreases in activity of the GH/IGF-I axis; and that as exercise training proceeds, levels of proinflammatory cytokines become reduced, and a rebound in IGF-I ensues leading to the higher IGF-I levels. METHOD: To test this, we evaluated the GH/IGF-I axis and levels of inflammatory cytokines (IL-6, TNF-alpha, IL-1beta, IL-1ra), body composition, and fitness in 13 healthy adolescent boys (mean age 15.9 +/- 0.3 yr) over the course of a high-school wrestling season. Subjects were tested preseason, midseason (6 wk), peak season (12-14 wk), and 4 wk postseason. RESULTS: No significant weight loss was noted throughout the season. During the wrestling season (mid and peak) both total (P < 0.046) and free (P < 0.002) IGF-I levels decreased, whereas proinflammatory cytokines (IL-1ra, P < 0.005; IGFBP-1, P < 0.013; and IGFBP-2, P < 0.025) increased. GHBP (P < 0.018) levels also decreased during the season. In the postseason, there were significant increases in GHBP, and free and total IGF-I, whereas proinflammatory cytokines decreased. CONCLUSIONS: An initial catabolic-type hormonal response occurs with intense exercise training in adolescents. This is followed by a rebound in circulating growth factors when the period of heavy training ceases.

Adolescent↗

PubMed2004

Hemodynamic and metabolic responses to hypergravity on a human-powered centrifuge.

INTRODUCTION: Microgravity causes the deconditioning of many physiological systems, and there is great interest in developing effective countermeasures. We recently developed a short-arm human-powered centrifuge, and the primary objective of this study was to assess the hemodynamic and metabolic responses to exercise under hypergravity conditions. METHODS: Phase I compared the hemodynamic and metabolic responses to 1 Gz (upright cycle ergometry) and 2 Gz conditions (Space Cycle) at the same work rate. Phase II contrasted the hemodynamic and metabolic responses at 2 and 3 Gz and at the same work rate. Phase III examined the BP and heart rate (HR) responses during passive and active centrifugation. Phase IV examined the relationship between work rate and oxygen uptake. RESULTS: In Phase I, the HR and BP responses were very similar between the two Gz conditions, with the exception that 2 Gz produced a lower diastolic BP in female subjects. In Phase II, both systolic and diastolic BPs were similar under the two different Gz conditions. However, there was a significant increase in HR at 3 Gz. In Phase III, the slope of the HR/Gz relationship was greater for passive conditions, suggesting that venous return is facilitated by the skeletal muscle pump. In Phase IV, it was found that there was a highly linear relationship between work rate and oxygen uptake. CONCLUSION: The results of this study demonstrate that exercise under low hypergravity conditions on the Space Cycle is well tolerated from a hemodynamic perspective.

Adult↗

PubMed2003

Negative energy balance plays a major role in the IGF-I response to exercise training.

Circulating IGF-I is correlated with fitness, but results of prospective exercise training studies have been inconsistent, showing both increases and decreases in IGF-I. We hypothesized that energy balance, often not accounted for, is a regulating variable such that training plus an energy intake deficit would cause a reduction in IGF-I, whereas training plus energy intake excess would lead to an increased IGF-I. To test this, 19 young, healthy men completed a 7-day strenuous exercise program in which they were randomly assigned to either a positive energy balance [overfed (OF), n = 10] or negative energy balance [underfed (UF), n = 9] group. IGF-I (free and total), insulin, and IGF-binding protein-1 were measured before, during, and 1 wk after the training. Weight decreased in the UF subjects and increased in the OF subjects. Free and total IGF-I decreased substantially in the UF group (P < 0.0005 for both), but, in the OF group, IGF-I remained unchanged. The UF group also demonstrated an increase in IGF-binding protein-1 (P < 0.027), whereas glucose levels decreased (P < 0.0005). In contrast, insulin was reduced in both the OF and UF exercise-training groups (P < 0.044). Finally, within 7 days of the cessation of the diet and training regimen, IGF-I and IGF-binding protein-1 in the UF group returned to preintervention levels. We conclude that energy balance during periods of exercise training influences circulating IGF-I and related growth mediators. Exercise-associated mechanisms may inhibit increases in IGF-I early in the course of a training protocol, even in overfed subjects.

Adolescent↗