Does combined antioxidant vitamin supplementation blunt repeated bout effect?

We investigated the effect of antioxidant supplementation on markers of muscle damage, antioxidant status, and delayed onset of muscle soreness (DOMS) after repeated downhill runs. Moderately-trained males (n=22) were randomly assigned to a supplement (S) or placebo (P) group. Capsules (vitamin C:1 000 mg/d; vitamin E: 400 IU/d) were ingested daily for 2 weeks. before the first (1D) and second (2D) downhill runs, and for 2 additional days following each run. Creatine kinase (CK) activity and oxygen radical absorbance capacity (ORAC) were measured pre-exercise and at 0 (immediately), 6, 24 and 48 h post-exercise (POST). DOMS was rated for quadriceps, hamstring, gluteus, gastrocnemius, and tibialis anterior at 0, 24, 48 and 72 h POST. CK at 48 h following 1D remained elevated above pre-exercise only in P (P<0.01). Overall, DOMS of the quadriceps was lower in S (1.1±0.3) than P (2.2±0.5) (P<0.05). At 24 h POST in S, CK was lower (P<0.01) and ORAC was higher (P<0.05) following 2D than 1D. CK and ORAC following 2D were blunted and augmented, respectively, in response to 1D and antioxidant supplementation enhanced this protective effect as indicated by an attenuation of biomarkers of muscle damage and a greater antioxidant capacity observed 24 h POST 2D.

Iron status in exercising women: the effect of oral iron therapy vs increased consumption of muscle foods.

Forty-seven previously sedentary women participating in a 12-wk moderate aerobic-exercise program were randomly assigned to one of four dietary groups: 50-mg/d iron supplement and a low food-iron diet (50 FE + EX), 10-mg/d iron supplement and a low food-iron diet (10 FE + EX), placebo and unrestricted diet (P + EX), and meat supplement and high food-iron diet (M + EX). A sedentary control group (n = 13) received no dietary interventions. Hematocrit, total iron-binding capacity, and hemoglobin, serum iron, serum ferritin, and serum albumin concentrations were measured every 4 wk. Hemoglobin values decreased at the end of 4 wk in all exercising groups compared with the control group. Iron status in the 50 FE + EX and M + EX groups improved after week 4 as indicated by an increase in serum ferritin, serum iron, and hemoglobin concentrations, and a decline in total iron-binding capacity. Thus, short-term, moderate aerobic exercise resulted in compromised iron status that was offset to varying degrees by ingesting iron or meat supplements. However, meat supplements were more effective in protecting hemoglobin and ferritin status than were iron supplements.

The in vitro dental plaque inhibitory properties of a series of N-[1-alkyl-4(1H)-pyridinylidene]alkylamines.

A series of novel N-[1-alkyl-4(1H)-pyridinylidene]alkylamine hydrohalides has been prepared and evaluated as inhibitors of dental plaque formation, in vitro. Several members of the series exhibited potency ca. 9-fold greater than that of chlorhexidine vs Streptococcus sobrinus 6715-13. The di-n-octyl analogue, 11 (pirtenidine), was found to be highly efficacious against several other oral plaque-forming microorganisms and is presently undergoing preclinical evaluation.

Excess postexercise oxygen consumption and recovery rate in trained and untrained subjects.

The purpose of this study was to determine whether aerobic fitness level would influence measurements of excess postexercise oxygen consumption (EPOC) and initial rate of recovery. Twelve trained [Tr; peak oxygen consumption (VO2 peak) = 53.3 +/- 6.4 ml . kg-1 . min-1] and ten untrained (UT; VO2 peak = 37.4 +/- 3.2 ml . kg-1 . min-1) subjects completed two 30-min cycle ergometer tests on separate days in the morning, after a 12-h fast and an abstinence from vigorous activity of 24 h. Baseline metabolic rate was established during the last 10 min of a 30-min seated preexercise rest period. Exercise workloads were manipulated so that they elicited the same relative, 70% VO2 peak (W70%), or the same absolute, 1.5 l/min oxygen uptake (VO2) (W1.5), intensity for all subjects, respectively. Recovery VO2, heart rate (HR), and respiratory exchange ratio (RER) were monitored in a seated position until baseline VO2 was reestablished. Under both exercise conditions, Tr had shorter EPOC duration (W70% = 40 +/- 15 min, W1.5 = 21 +/- 9 min) than UT (W70% = 50 +/- 14 min; W1.5 = 39 +/- 14 min), but EPOC magnitude (Tr: W70% = 3.2 +/- 1.0 liters O2, W1.5 = 1.5 +/- 0.6 liters O2; UT: W70% = 3.5 +/- 0.9 liters O2, W1.5 = 2.4 +/- 0.6 liters O2) was not different between groups. The similarity of Tr and UT EPOC accumulation in the W70% trial is attributed to the parallel decline in absolute VO2 during most of the initial recovery period. Tr subjects had faster relative decline during the fast-recovery phase, however, when a correction for their higher exercise VO2 was taken. Postexercise VO2 was lower for Tr group for nearly all of the W1.5 trial and particularly during the fast phase. Recovery HR kinetics were remarkably similar for both groups in W70%, but recovery was faster for Tr during W1.5. RER values were at or below baseline throughout much of the recovery period in both groups, with UT experiencing larger changes than Tr in both trials. These findings indicate that Tr individuals have faster regulation of postexercise metabolism when exercising at either the same relative or same absolute work rate.

Changes in lung volume and breathing pattern during exercise and CO2 inhalation in humans.

Lung volume changes during CO2 inhalation and exercise were compared in seven human subjects. Expiratory reserve volume (ERV) normalized by vital capacity (VC) was used as an index of end-expiratory lung volume (EELV). Work loads tried were 30, 60, and 90 W and inspired CO2 concentrations were 3.5 and 5.0%. Exercise at 30 W led to a significant decrease in EELV, by 7% VC (P less than 0.005), with no further change at higher levels of exercise (P greater than 0.1). Both 3.5 and 5.0% CO2 inhalation resulted in an increase in EELV that was not statistically significant (3% VC, P greater than 0.1). A possible linkage of this different EELV behavior to breathing pattern was tested. The tidal volume-inspiratory duration curve shifted to a higher volume region during exercise compared with CO2 inhalation. Consequently, the volume-time threshold characteristic was better described by an end-inspiratory lung volume-inspiratory duration plot, resulting in a common relationship under these two different stimuli. These results suggest that the depth and rate of breathing in humans can be affected by not only phasic but also tonic components. A decrease in functional residual capacity or EELV was peculiar to exercise and should be associated with increased mechanical efficiency compared with CO2 inhalation. Theoretical predictions based on work of breathing optimization via a decreased EELV seemed to be capable of explaining isocapnic exercise hyperpnea in conjunction with proportional control of arterial CO2 tension.

Ventilatory response to CO2 and O2 near eupnea in awake dogs.

The problem faced in determining the ventilatory response to CO2 near eupnea has been the difficulty of unloading metabolically produced CO2 from the subject in the steady state. Previous methods using extracorporeal circuits to unload CO2 are technically difficult and provide a limited number of experimental states per experiment. Using the method of high-frequency ventilation to unload CO2, we were able to obtain a large number of determinations in the same subject under conditions of hypoxia, normoxia, and hyperoxia. Data collected in five awake dogs show that the ventilatory response to CO2 is linear down to apnea during normoxic conditions but exhibits nonlinear behavior dependent on the level of arterial O2 tension. During hyperoxic conditions, the response was concave curvilinear, with a statistically significant decrease in slope near apnea. In contrast, mild hypoxia led to a convex curvilinear response with an increased slope near apnea.

Kyphosis in active and sedentary postmenopausal women.

UNLABELLED: EAGAN, M. S., and D. A. SEDLOCK. Kyphosis in active and sedentary postmenopausal women. Med. Sci. Sports Exerc., Vol. 33, No. 5, 2001, pp. 688-695. PURPOSE: This study examined kyphosis in relation to self-reported activity level (sedentary, active) and activity type (weight-bearing land, nonweight-bearing water) in 61 postmenopausal women aged 60-78 yr. METHODS: Specifically, we measured kyphosis, muscle strength (defined as back extensor (BES) and grip (GS) strength), total calcium intake, body fat, height lost since age 30 (HtLost), current activity level for household, leisure and sport activities and their total, as well as occupational and physical activity history and their total. RESULTS: No significant differences (P > 0.05) were found for any variables when subjects were divided into sedentary (N = 18), land (N = 29), and water (N = 14) groups; exercisers (N = 43) and nonexercisers (N = 18); or between the top and bottom tertiles of lifetime active (N = 20) and inactive (N = 20) women. Stepwise multiple regression yielded body fat as the single best predictor of kyphosis accounting for 6.9% of the total variance (P < 0.04) with the resulting equation: kyphosis (degrees) = 22.919 + 0.627*body fat (%) + 0.852*HtLost (cm) + 2.881E-0.03*total calcium intake (mg) (r2 = 0.22, SEE = 7.7). Significant relationships (P < 0.05) included kyphosis with body fat (r = 0.26) and HtLost with age (r = 0.50). Relationships (P < 0.05) regarding muscle strength included: GS and BES with age (r = -0.38, -0.30), HtLost (r = -0.39, -0.36), and occupational activity history (r = 0.28, 0.35), as well as BES with household activity and total activity history (r = 0.28, 0.30). Physical activity history was related (P < 0.05) to current sport, leisure, and total activity history (r = 0.37, 0.42, 0.93, respectively). CONCLUSION: Women who are active when younger seem to be active and stronger as older adults. However, this does not seem to impact kyphosis. The measured variables accounted for a small proportion of kyphosis variance, suggesting that more potent causative factors of this spinal malformation exist.

Circulatory and thermal adjustments to prolonged exercise in paraplegic women.

The circulatory and thermal responses to 90 min of wheelchair ergometer exercise were examined in five wheelchair dependent (WD) women with low level spinal dysfunction and five able-bodied (AB) women who served as a comparison group. Metabolic rate during exercise was 221 W for WD and 255 W for AB (P greater than 0.05). Oral temperature (Tor), mean skin temperature (Tsk), oxygen uptake (VO2), heart rate (HR), and cardiac output (Qc) were assessed periodically throughout the exercise period. Ambient conditions were 24-25 degrees C and 38-52% relative humidity. A significant group X time interaction was found for Tor (P less than 0.001) and Tsk (P less than 0.001). Tor of the WD group steadily increased during the exercise, whereas the AB group showed a stable Tor. Tsk of WD increased rapidly during the first 5-10 min of exercise and continued to rise at a slower rate throughout the exercise. In contrast, Tsk of AB rose to a peak during the first 10 min and then showed a decreasing trend. VO2 and HR remained stable in both groups throughout the exercise period. Following an initial increase in Qc from minute 10 to minute 20 in both groups, values for WD continually decreased until Qc at 80 min was 14% lower than at 10 min. The findings suggest that the WD women had greater thermoregulatory strain than the AB women as indicated by a higher Tor and Tsk and by an inability to maintain Qc due to paralysis of the lower limbs and perhaps an increase in cutaneous blood volume.

Effect of exercise intensity and duration on postexercise energy expenditure.

The purpose of this study was to examine 1) the effect of two exercise intensities of equal caloric output on the magnitude (kcal) and duration of excess postexercise oxygen consumption (EPOC) and 2) the effect of exercise of equal intensity but varying duration on EPOC. Ten trained male triathletes performed three cycle ergometer exercises: high intensity-short duration (HS), low intensity-short duration (LS), and low intensity-long duration (LL). Baseline VO2 was measured for 1 h prior to each exercise condition. Postexercise VO2 was measured continuously until baseline VO2 was achieved. The duration of EPOC was similar for HS (33 +/- 10 min) and LL (28 +/- 14 min), and both were significantly longer (P less than 0.05) than the EPOC following LS (20 +/- 5 min). However, total net caloric expenditure was significantly more (P less than 0.05) for HS (29 +/- 8 kcal) than for either LS (14 +/- 6 kcal) or LL (12 +/- 7 kcal). The exercise conditions used in this study did not produce a prolonged EPOC. However, the exercise intensity was shown to affect both the magnitude and duration of EPOC, whereas the exercise duration affected only the duration of EPOC. Moreover, the duration of EPOC and the subsequent caloric expenditure were not necessarily related. Based on the resulting magnitude of the postexercise energy expenditure, it is possible that EPOC may be of some value for weight control over the long term.

Previous physical activity relates to bone mineral measures in young women.

Exercise may increase accretion of bone, potentially reducing the risk of osteoporosis. Previous physical activity was assessed in 204 minimally active young women (18-31 yr). Bone mineral content (BMC) and bone mineral density (BMD) for the total body, femoral neck, and spine were assessed by a dual x-ray absorptiometer, and the radius by a single photon absorptiometer. Self-reported occupation and leisure activity for the 5 yr before enrollment in the study, as well as high school and college sports participation, were assigned energy expenditure (EE) values. From this information, EE variables were created as follows: 1) occupation EE + leisure EE + high school sport and/or college sport EE if within prior 5 yr (5-yr EE); 2) occupation EE + leisure EE (occupation + leisure EE); and 3) high school sport EE (high school EE). These variables were correlated with bone mineral measures and significant results follow (P < 0.05). Five-year EE and occupation + leisure EE correlated with all measures of bone health (r from 0.13 to 0.39). High school EE correlated with total body BMD (r = 0.25) and BMC (r = 0.28), femoral neck BMD (r = 0.28), radius BMC (r = 0.20), as well as spine BMD (r = 0.20) and BMC (r = 0.27). When weight was controlled, 5-yr EE and occupation + leisure EE remained correlated with all BMC measures (r from 0.14 to 0.22). When controlled for weight, high school EE remained associated with femoral neck BMD (r = 0.24), total body BMD (r = 0.20) and BMC (r = 0.26), and spine BMC (r = 0.17). To partially control for selection bias, data were also controlled for total body BMD. Five-year EE and occupation + leisure EE remained positively correlated with all measures of BMC. High school EE remained correlated both with femoral neck BMD and total body BMC. In multiple regression analyses, 5-yr EE or occupation + leisure EE were significant predictors of all measures of bone health, except femoral neck BMD. High school EE was a significant predictor for total body BMD and BMC, femoral neck BMD, and spine BMC.

Effects of long-term moderate exercise on iron status in young women.

The impact of long-term (6-month) moderate exercise on the iron status of previously sedentary women was determined by randomly assigning 62 college-age women into one of the following four groups: 1) 50 mg.d-1 iron supplement, low iron diet (N = 16); 2) Placebo, free choice diet (N = 13); 3) Meat supplement to achieve 15 mg.d-1 iron intake (N = 13); and 4) Control, free choice diet (N = 20). All groups except the Control group exercised 3 d.wk-1 at 60%-75% of their heart rate reserve. VO2max was measured at baseline and week 24. Blood was sampled at baseline and every 4 wk thereafter for 24 wk to measure iron status and to elucidate the causes for alterations in iron status. Subjects had depleted iron stores throughout the study as indicated by their serum ferritin levels (< 15 ng.ml-1). Serum iron, total iron binding capacity and transferrin saturation were not compromised with exercise. Mean hemoglobin level in the Placebo/Ex group was significantly (P < 0.05) lower than the 50 Fe/Ex and the Meat/Ex groups by week 24. However, changes in serum albumin, haptoglobin, and erythropoietin data from the study cannot explain these changes.

Impact of exercise on bone health and contraindication of oral contraceptive use in young women.

PURPOSE: The effect of quantified resistance and high impact exercise training on bone mass as modified by age and oral contraceptive (OCont) use in young women was studied. METHODS: Women were categorized by age (18-23 vs 24-31 yr) and OCont use, and were then randomized into either three sessions of resistance exercise plus 60 min.wk-1 of jumping rope or a control group for 24 months. Total body, spine, femoral neck, greater trochanter, Ward's area, and radial bone mineral density (BMD) and/or content (BMC), biochemical markers of bone turnover, dietary intake of calcium, lean body mass, maximal oxygen uptake, and strength were determined at baseline and every 6 months. RESULTS: Total body (TB) BMC percent change from baseline was higher in exercisers compared with nonexercisers at 6 and 24 months. OCont users had lower bone turnover at baseline and a decrease in TBBMC from baseline compared with non-OCont users at 24 months. Spine BMC and BMD decreased in the exercise and OCont group at 6 months and remained significantly below nonexercisers who used oral contraceptives at 2 yr. Femoral neck BMD also decreased in the exercise and oral contraceptive group at 6 months. CONCLUSIONS: Exercise prevented a decline in TBBMC seen in the nonexercisers. On the other hand, exercise in oral contraceptive users prevented the increase observed in the spine of the nonexercise plus OCont group.

WIN 66306, a new neurokinin antagonist produced by an Aspergillus species: fermentation, isolation and physico-chemical properties.

WIN 66306 (1a), a cyclic peptide containing a novel amino acid, was isolated as a neurokinin antagonist from an Aspergillus species, labelled SC230. Conditions that maximized the production of 1a were developed, leading also to production of the related compound WIN 68577 (2) and rosellichalasin (3). Both 2 and 3 were more active in the rat NK1 than in the human NK1 receptor binding assay, while 1a was more active at the human receptor with an inhibitor affinity constant of 7 microM.

Benzomalvins, new substance P inhibitors from a Penicillium sp.

In the course of screening microbial broths for neurokinin receptor antagonists, a series of new benzodiazepines, benzomalvins A (1), B (2) and C (3), has been isolated from the culture broth of a fungus identified as a Penicillium sp. Benzomalvin A (1) showed inhibitory activity against substance P with Ki values of 12, 42 and 43 microM at the guinea pig, rat and human neurokinin NK1 receptors, respectively. Benzomalvins B (2) and C (3) were only weakly active. The structures of these compounds were determined by spectroscopic methods including MS measurements and NMR analysis.

WIN 64821, a novel neurokinin antagonist produced by an Aspergillus sp. I. Fermentation and isolation.

WIN 64821, a nonpeptide neurokinin antagonist, was isolated from a strain of Aspergillus sp., SC319. The compound was produced in different fermentation media with greatest yields observed when the culture was grown in a synthetic medium supplemented with L-tryptophan and L-phenylalanine. After 6 days fermentation, yields greater than 600 mg/liter were obtained. Two analogs of WIN 64821 were also identified in the culture extracts and subsequently tested for biological activity. WIN 64821 was the most potent compound isolated from this culture and exhibited activity as a substance P-binding inhibitor with submicromolar potency against the human neurokinin 1 receptor.

WIN 64821, a novel neurokinin antagonist produced by an Aspergillus sp. II. Biological activity.

WIN 64821, a secondary metabolite produced by Aspergillus sp. (ATCC 74177) was found to inhibit radiolabeled substance P (SP) binding in a variety of tissues, including those of human origin. This compound inhibited, in a competitive manner, the binding of SP with Ki values ranging from 0.24 microM in human astrocytoma U-373 MG cells to 7.89 microM in rat submaxillary membranes. Additionally, WIN 64821 was found to inhibit 125I-NKA binding to the NK2 receptor in human tissue at a concentration equivalent to its NK1 activity (0.26 microM). The inhibitory activity of WIN 64821 against an NK3 selective ligand, 3H-senktide, was found to be much weaker (Ki = 15.2 microM). WIN 64821 was also evaluated in NK1 functional assays and was found to be a competitive antagonist of SP-induced contractility in the guinea pig ileum (pA2 = 6.6) as well as an inhibitor of SP-induced 45Ca2+ efflux from human astrocytoma U-373 MG cells (IC50 = 0.6 microM). In a rat vas deferens model, WIN 64821 inhibited eledoisin-induced contractility with an IC50 of 3.4 microM indicating functional antagonism at the NK2 receptor. The data presented in this study provide biochemical, pharmacological and functional evidence supporting WIN 64821 as a competitive neurokinin antagonist.

Antimycins, inhibitors of ATP-citrate lyase, from a Streptomyces sp.

A related group of compounds belonging to the antimycin class of antibiotics was found in culture broth produced by a Streptomyces species. The group includes known antimycins A1, A2, A3 and A4, and new antimycins A7 and A8. These compounds inhibit ATP-citrate lyase with Ki values of 4 to 60 microM against the substrate magnesium citrate. The structures of the new antimycins were determined by spectroscopic analyses.

Fitness level and postexercise energy expenditure.

This study was designed to investigate the effect of fitness level on excess postexercise oxygen consumption (EPOC) in five endurance trained and five sedentary male volunteers. The possible influence of differences in body weight and exercise energy expenditure were controlled by employing a weight-supported (cycle ergometer), 300 kilocalorie exercise. Exercise intensity was equal to 50% of each subject's previously determined peak oxygen uptake (VO2). VO2 was measured for 1 hr prior to exercise to establish the baseline value, and continuously in the postexercise period until the baseline value was achieved. Duration of EPOC was 16.6 +/- 3.1 minutes and 20.4 +/- 7.8 minutes in the fit and unfit groups, respectively (p > 0.05). Magnitude of EPOC, which was not significantly different between the groups, averaged 12.2 +/- 3.1 kcal in the fit and 12.2 +/- 4.3 kcal in the unfit group. The results suggest that EPOC following a weight-supported exercise of an intensity and duration frequently used by individuals who begin an exercise program for weight control is not compromised by differences in body weight or fitness level.

Correlates of blood pressure in elementary schoolchildren.

This cross-sectional study determined which anthropometric, dietary, and physical fitness variables were best predictors of blood pressure (BP) in 323 white elementary schoolchildren. Height, weight, triceps, and subscapular skinfold thickness were measured, followed by two resting BP measurements. Cardiorespiratory fitness was assessed by time in a one mile run. A food frequency questionnaire measured habitual dietary intake. Correlational analysis revealed height, weight, body mass index (wt/ht2), and skinfold thicknesses were anthropometric variables associated significantly with both systolic and diastolic blood pressure. Physical fitness was not correlated with BP and, among dietary variables, only estimated daily caloric intake, dietary cholesterol, and nondiscretionary sodium were related to blood pressure. A multiple regression analysis selected weight, body mass index (BMI), and total caloric intake as factors explaining the greatest amount of BP variability. For some individuals, hypertension may originate in childhood, thus, these results could have implications for primary prevention of high blood pressure.