Biomedical subjects

T J Vasankari

Publications and source records attributed to T J Vasankari.

10 recordsLinked to original sources

PubMed2006

Successful weight maintenance preserves lower levels of oxidized LDL achieved by weight reduction in obese men.

OBJECTIVE: We studied the association between weight maintenance, oxidized low-density lipoprotein (ox-LDL) and other lipoproteins in obese men. METHODS: A 2-month weight reduction phase (WRP) with a very-low-energy diet was followed by a 6-month weight maintenance period and an unsupervised 2-year follow-up. Ninety men entered and 68 (76%) completed the study. Subjects were analyzed as one group and after division into two subgroups: 20 most successful men in maintaining the lost weight (subgroup 1) and the remaining (n=48) men (subgroup 2). Ox-LDL was measured by quantifying the amount of conjugated dienes in LDL particles. RESULTS: The mean (+/-s.d.) weight reduction at the end of the WRP (n=68) was 14% (confidence interval (CI) 12.9-14.7%, 14.5+/-4.2 kg, P<0.001). Ox-LDL decreased by 22% (CI 16.9-28.1, 12.3+/-15.4 micromol/l, P<0.001). At the end of the 2-year follow-up, the regain in weight from the end of the WRP was 11% (CI 9.0-12.4, 9.6+/-6.2 kg, P<0.001). The regain in ox-LDL was 30% (CI 18.7-41.2, 8.2+/-15.4 micromol/l, P<0.001). In subgroup 1 vs 2, the respective regains were 3% (CI 0.9-4.2, 2.2+/-3.0 kg, P=0.006) vs 14% (CI 12.7-15.6, 12.9+/-4.0 kg, P<0.001) regarding weight and 9% (2.0+/-6.9 micromol/l, P=NS) vs 39% (CI 23.7-53.9, 11.2+/-17.2 micromol/l, P</=0.001) in ox-LDL. CONCLUSION: The favorable changes seen in ox-LDL particles and serum lipids during weight reduction could be maintained by keeping the weight reduced, which may indicate decreased risk of atherosclerosis. But weight regain causes a resurge of ox-LDL.

Adult↗

PubMed1998

Reduced oxidized LDL levels after a 10-month exercise program.

PURPOSE: We studied the effect of a 10-month exercise program on LDL oxidation and other lipid risk factors in 34 sedentary men and 70 women. We hypothesized that decreasing LDL oxidation by raising exercise activity would decrease the risk of atherosclerosis. METHODS: The men and women subjects had a mean (range) age of 43.6 (34-52) and 44.6 (31-58) yr, a body mass of 94.4 (78-144) and 77.6 (56-117) kg, a body mass index of 29.6 (24-44) and 28.6 (21-41), a body fat percentage of 20.4 (13-29) and 31.4 (16-39), and a maximal oxygen uptake of 33.3 (15-50) and 30.4 (18-49) mL.kg-1.min-1, respectively. We measured the baseline levels of conjugated dienes extracted from LDL (LDL-BDC) to assess the amount of circulating LDL oxidation products. The antioxidant potential of LDL samples was estimated in vitro by their potency to resist 2,2'-azobis(2-amidinopropane)HCl-induced peroxidation. The exercise program was tailored individually based on indirect measurement of VO2max at baseline. RESULTS: The mean time of exercise was 257 min.wk-1 for men and 209 min.wk-1 for women. Estimated VO2max increased by 19% during the exercise program in both men and women (both P < 0.0001). Concurrently, the concentration of HDL cholesterol increased by 15% in men (P = 0.0004) and 5% in women (P = 0.043) and that of LDL cholesterol decreased by 10% (P = 0.026) and 11% (P < 0.0001), respectively, whereas serum total cholesterol and triglyceride concentrations remained unchanged. The concentrations of LDL-BDC decreased by 23% (P = 0.0010) and 26% (P < 0.0001) and the ratio of LDL-BDC to LDL by 14% (P = 0.016) and 18% (P < 0.0001) in men and women. The ratio of LDL antioxidant potential to LDL rose by 16% (P = 0.011) and 11% (P = 0.0016), respectively. The mean weight loss during the exercise program was 2.9 kg in men and 1.8 kg in women (both P < 0.0001), whereas body fat percentage fell by 2.3% and 3.2%, respectively. CONCLUSIONS: In addition to increasing HDL cholesterol and decreasing LDL cholesterol, the exercise program is concluded to have improved the quality of the circulating LDL (less oxidized LDL), which may reduce the risk of atherosclerosis.

Adipose Tissue↗

PubMed1997

The effect of endurance exercise at moderate altitude on serum lipid peroxidation and antioxidative functions in humans.

We investigated the effect of training and racing at moderate altitude (MA) on oxidative stress by assessment of serum diene conjugation (DC) and serum antioxidant potential (TRAP). Nine male top level skiers were studied during a national race (20-30 km) at sea level (SL). Thereafter, the athletes trained for 2 weeks at MA, after which they participated in a 20-30 km race at MA. Venous blood samples were taken before and after the race. The DC, indicating early events of lipid peroxidation, did not change during the race at SL (16 850 vs 15 900 delta Absorbance.l-1) or at MA (19 870 vs. 20 630 delta Abs.l-1). At MA serum DC was higher than at SL both before (25%) and after (30%) the race, the postrace difference being statistically significant (P < 0.05). The TRAP increased during the race at MA (from 1387 to 1943 mumol.l-1, P = 0.016), but not at SL (1713 vs 1582 mumol.l-1). These observations would suggest that the level of oxidative stress might be greater during living, training and racing at MA (higher DC levels). Increased TRAP during the race at MA may indicate that the physiological adaptation to extreme acute oxidative stress was altered. The physiological significance of this observation remains to be investigated.

Adult↗

PubMed1997

Effects of acute prolonged exercise on-serum and LDL oxidation and antioxidant defences.

We investigated the acute effects of long-distance running on oxidation of lipids and antioxidant functions in LDL and serum. Eight trained male runners who participated in a 31-km run and 22 male keep-fit runners who participated in a marathon run were enrolled into the study. Venous blood samples were taken before and immediately after the exercise. There were no changes in LDL diene conjugation (LDL-DC) or LDL antioxidant potential (LDL-TRAP) during the exercises. Serum (S-) TRAP and S-alpha-tocopherol rose during the 31-km run (by 22%, p = .0005, and by 29%, p = .011, respectively), and during the marathon (by 16%, p = .0014, and by 7%, p = .031, respectively). S-DC rose during the 31-km run (by 9%, p = .0026), but not during the marathon (p = .14). Preexercise and postexercise S-alpha-tocopherol correlated positively with pre and postexercise S-TRAP in the marathon run (r = .473, 95% CI 0.064 to 0.746, and r = .524, 95% CI 0.131 to 0.774, respectively). Thus, the paradoxical exercise-associated increase in S-TRAP is, at least in part, explained by a simultaneous rise in S-alpha-tocopherol concentration. However, acute exercise does not change LDL-DC or LDL-TRAP concentrations.

Adult↗

PubMed1997

Familial aggregation of LDL oxidation.

The "oxidation hypothesis" states that oxidative modification of low-density lipoprotein (LDL) is important in the pathogenesis of the atherosclerotic lesion. We studied 15 families (fathers, mothers and male twins of 16 to 18 years of age) to investigate the familial aggregation of LDL oxidation. As an indicator of LDL oxidation products we measured baseline levels of conjugated dienes extracted from LDL (LDL-BDC). For this analysis LDL was first isolated by rapid precipitation with buffered heparin. LDL-BDC was highest in fathers (mean 673 delta Abs per mg LDL cholesterol, 95% confidence interval (CI) 547-800) followed by mothers (500, 95% CI 408-592) and twins (383, 95% CI 337-430). There was a high correlation in the LDL-BDC between the identical twins (r = 0.81, 95% CI 0.44-0.95), but no correlation between the parents (r = -0.36). The LDL-BDC of boys correlated positively with that of fathers (r = 0.49, 95% CI 0.16-0.72), but not with that of mothers (r = 0.00). Highly significant positive correlations were observed between LDL-BDC and serum lipid risk factors among parents, but among twins the correlations were usually weaker. Our study suggests that inherited factors contribute to interindividual variability in the oxidative modification of LDL.

Adolescent↗

PubMed1997

Increased serum and low-density-lipoprotein antioxidant potential after antioxidant supplementation in endurance athletes.

We studied the effect of antioxidant supplementation on acute exercise-induced lipid peroxidation and antioxidant potential measured in serum and low-density-lipoprotein (LDL) samples. Eight endurance athletes repeated a 31-km running exercise twice with an interval of 4 wk. During the 4 wk before the runs, the subjects took in a single-blind randomized order either a combination of antioxidant supplements (the antioxidant trial; 294 mg vitamin E, 1000 mg vitamin C, and 60 mg ubiquinone daily) or placebo (the placebo trial). Venous blood samples were taken before and immediately after the 31-km run in both trials. Antioxidant supplementation raised the LDL antioxidant potential (TRAP) (40% and 30%, P = 0.0031), serum TRAP (9% and 10%, P = 0.0037), and serum alpha-tocopherol concentration (by 59% and 66%, P = 0.0004) in both pre- and postexercise samples, respectively. The supplementation did not, however, affect the concentration of LDL diene conjugation (DC) or of serum DC. Physical exercise increased serum DC (by 18% and 10%, P = 0.0004) but not LDL-DC, and the quantity of the increment of serum DC was not affected by antioxidant intervention. The major cause for the increased LDL-TRAP and serum TRAP after antioxidant supplementation is apparently the elevation of the serum alpha-tocopherol concentration.

Adult↗

PubMed1993

The effect of ski training at altitude and racing on pituitary, adrenal and testicular function in men.

The effect of similar prolonged exercise on hormonal changes was studied at sea level and at moderate altitude. Four cross-country skiers participated in a 30-km race and five biathlonists in a 20-km race at sea level in Finland and during altitude training and racing at 1650 m in Les Saisies, France. Venous blood samples were taken at both altitudes before the race between 0800 and 0900 hours and 25-35 min after the race. Resting blood samples were also taken before and after the altitude training and the period of racing. Serum testosterone concentration was higher before the race at altitude than at sea level (19%, P < 0.02), and 30 min after the race growth hormone (GH) concentration was higher at sea level than at moderate altitude (P < 0.002). There were not significant differences in serum luteinising hormone between the altitudes. Serum cortisol concentration was higher after the altitude training and the period of racing than before (P < 0.02) but no difference was observed in testosterone. We concluded, that since the profiles of the anabolic-catabolic hormone concentrations measured are indicators of the performance level of athletes, our data indicated that to follow them during altitude training could be beneficial in optimizing training programme for individual athletes. We also concluded, that the lower GH concentration after racing at moderate altitude may have been a consequence of decreased racing speed and/or increased physical performance.

Adrenal Glands↗

PubMed1993

Pituitary-gonadal response to gonadotropin-releasing hormone stimulation is enhanced in men after strenuous physical exercise.

The effects of strenuous physical exercise were studied on the pituitary-testicular response to gonadotropin-releasing hormone (GnRH) stimulation and on growth hormone (GH) and cortisol secretion. Eight healthy adult males were injected twice intravenously with 0.1 mg of GnRH at intervals of 21 days. At the time of the first injection (exercise trial) the subjects had been bicycling for 4 h on the road, and at the time of the second injection (rest trial) they had been resting in a sitting position for 4 h. Blood samples were taken before and after the 4-h period and 30, 60 and 120 min after the GnRH injection. Both testosterone and luteinizing hormone (LH) decreased during the exercise by 18% (p = 0.037) and 29% (p = 0.0028), respectively, but increased after the GnRH injection by 1.4- and 12.9-fold (p = 0.0001 for both). The areas under the testosterone and LH response curves after GnRH were significantly larger in the exercise trial than in the rest trial, threefold (p = 0.013) and 1.3-fold (p = 0.0007), respectively. Growth hormone and cortisol increased during the exercise trial. In the rest trial, the GnRH injection increased serum GH concentrations (p = 0.027). In conclusion, the diminished hypothalamic GnRH secretion seems to be the major cause of the post-exercise decrease in LH and testosterone, but altered sensitivity of the pituitary to GnRH also may be involved. Apparently, the build-up of pituitary LH stores during exercise explains the enhanced LH and testosterone response to GnRH challenge after exercise in comparison to control GnRH challenge.

Adult↗

PubMed1993

Effects of endurance training on hormonal responses to prolonged physical exercise in males.

The effect of several years' endurance training on hormonal changes during acute prolonged physical exercise was studied. In trial I, 13 cross-country skiers were studied before and after a 75-km ski race and 3 weeks later on a control day. In trial II, 10 trained and 8 untrained subjects bicycled for 4 h on the road with as high a performance level as possible. Venous blood samples were taken in both trials before and after the exercise. In trial I, serum concentrations of luteinizing hormone (p < 0.01) and follicle-stimulating hormone (FSH, p < 0.001) decreased more from morning to afternoon samples, and cortisol (p < 0.001) and growth hormone (GH, p < 0.001) increased more during the ski race when compared to the control day. Serum testosterone decreased during the ski race (p < 0.01) but not on the control day. In trial II, a group difference was seen in serum FSH levels which was higher in the trained than untrained subjects at all three time points (F = 4.66, p = 0.046). A significant trial-group interaction (p = 0.020) was seen in GH, the GH being lower before exercise and higher 2 h after exercise in the untrained subjects. There was a significant group contrast between pre- and post-exercise samples in testosterone (p = 0.021) and cortisol (p = 0.022). In conclusion, the higher basal FSH concentration in the trained versus untrained subjects may be a sign of compensated hypogonadism due to intensive chronic training or it may be due to dysfunction of Sertoli cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Carbohydrate ingestion during prolonged running exercise results in an increase of serum cortisol and decrease of gonadotrophins.

We tested the hypothesis that improved availability of energy through carbohydrate ingestion could counteract the documented suppression of pituitary-gonadal function during prolonged exercise. Nine trained males repeated twice a 36 kilometre running exercise with two weeks interval. During the tests the subjects ingested in a randomized single-blind fashion a total of 1050 millilitres of carbohydrate and placebo solutions. The total amount of ingested carbohydrate was 105 grams. Venous blood samples were taken before the exercise (sample A), immediately after exercise (B), and 2 hours later (C). In the B samples plasma glucose was 14% higher (P less than 0.01) and serum cortisol 13% higher (P less than 0.05) in the carbohydrate than in the control trial. In contrast, the level of LH was 18% (P less than 0.05) and that of FSH 11% lower (P less than 0.05) in the carbohydrate than in the placebo trial. Serum testosterone concentration did not differ between the treatment groups. We conclude that carbohydrate ingestion does not counteract the exercise-associated suppression of gonadotrophin secretion, but results in paradoxical increase of serum cortisol and decrease of LH and FSH, in comparison to placebo-treated controls. The higher cortisol level in carbohydrate group may be secondary to higher insulin levels.

Adult↗