Biomedical subjects

M Ahotupa

Publications and source records attributed to M Ahotupa.

At least 37 records · Page 2Linked to original sources

PubMed1998

Baseline diene conjugation in LDL lipids as a direct measure of in vivo LDL oxidation.

OBJECTIVES: To additionally test validity of the recently developed method (LDL baseline diene conjugation, LDL-BDC) for determination of circulating oxidized LDL. DESIGN AND METHODS: A detailed comparison between the ultracentrifugation and heparin precipitation methods for LDL isolation was performed to test suitability of the fast precipitation method. Validity of LDL-BDC as an indicator of circulating oxidized LDL was tested by comparing LDL-BDC to results obtained by the immunological autoantibody method. RESULTS: BDC values in LDL isolated by heparin precipitation did not differ from those isolated by sequential ultracentrifugation. While highest amount of diene conjugation was found in LDL (40% of that in serum), substantial amounts were also found in VLDL (31%) and HDL (25%). When analyzed in the same samples, assays for the titer of autoantibodies against oxidized LDL and LDL-BDC were found to show good correlation (r = 0.57, p = 0.001, n = 29). CONCLUSIONS: These results, together with thus far conducted studies on clinical applicability of the method, indicate that LDL-BDC is a promising candidate in search for a method for estimation of LDL oxidation in vivo.

Adult↗

PubMed1998

Blood vitamins, mineral elements and inflammation markers as risk factors of vascular and non-vascular disease mortality in an elderly population.

BACKGROUND: The need for protecting agents against degenerative processes of the body has been proposed to be especially high in elderly people. In order to evaluate the prognostic value of various biochemical factors in ageing the associations of blood concentrations of several vitamins, mineral elements and some other suggested risk factors with vascular and non-vascular mortality were studied in an elderly population. METHODS: A large health survey with complete clinical evaluation was carried out in the City of Turku in 1982-1983. A random sample of 344 community-living elderly individuals aged 65 years or older, stratified into four age groups, was studied. During the 13 years follow-up 225 subjects had died. Calcium, magnesium, copper, ceruloplasmin, zinc, selenium, iron, ferritin, transferrin, alpha-tocopherol, retinol, folate, vitamin B12, malondialdehyde, orosomucoid and insulin levels were analysed from the blood specimens. The relations between the compounds measured and relative mortality risks during the 13-year follow-up were analysed by Cox proportional hazards model adjusting for other known risk factors. RESULTS AND CONCLUSIONS: High concentrations of serum copper, orosomucoid and insulin were associated with increased risk of vascular mortality. The relative risks within the subjects of the highest tertile of serum concentrations were 2.2 for copper, 1.8 for orosomucoid, and 1.8 for insulin when adjusted for many confounding risk factors. Low serum vitamin B12 concentrations appeared to be significantly (P = 0.01) associated with increased vascular mortality. The associations were essentially not more significant when adjusted only for age. Contrary to earlier observations concentrations of serum magnesium, selenium, alpha-tocopherol, iron and its binding proteins or plasma and erythrocyte folate were not associated with increased mortality risk when adjusted for confounding risk factors. The authors suggest that in elderly subjects these elements and compounds are at the most weak, and probably non-independent risk factors for vascular mortality.

Aged↗

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↗

PubMed1998

The effect of vitamin C and E on placental lipid peroxidation and antioxidative enzymes in perfused placenta.

BACKGROUND: To investigate placental lipid peroxidation products and antioxidative enzymes after vitamin C and/or E infusions into the maternal circulation of normal and preeclamptic placentas perfused in vitro. METHODS: Placentas from 29 normal and six preeclamptic women delivered between 27 and 41 weeks of gestation were used in the study. RESULTS: Neither vitamin C (500 microM) nor vitamin E (50 microM) had any effect on placental lipid peroxidation or antioxidative enzymes in normal placentas. Vitamin C infused in preeclamptic placentas decreased peroxidation potential, as an indicator of lipid peroxidation to the same level it was in normal placentas (812 vs. 649 mV/mgprot; p=0.420). The activity of superoxide dismutase (SOD) was lower (1350 vs. 2030 ng/mgprot; p=0.023) in preeclamptic placentas, and the activities of glutathione peroxidase (0.22 vs. 0.08 micromol/min x mgprot; p=0.010) and glutathione-S-transferase (19.8 vs. 13.1 micromol/min x mgprot; p=0.016) were higher in preeclamptic compared to normal placentas. CONCLUSION: In this study, based on in vitro perfused normal and preeclamptic placentas, exogenous antioxidative vitamins had no effect on lipid peroxidation or endogenous antioxidative enzymes in normal placenta, but reduced placental lipid peroxidation and could potentiate the activity of some endogenous placental antioxidative enzymes in preeclamptic placenta.

Ascorbic Acid↗

PubMed1998

Effects of ascorbic acid and carbohydrate ingestion on exercise induced oxidative stress.

BACKGROUND: We studied the effects of supplementation of vitamin C and carbohydrate on acute exercise-induced lipid peroxidation. METHODS EXPERIMENTAL DESIGN: two randomized controlled trials. PARTICIPANTS: 17 endurance athletes. INTERVENTIONS: in study I, nine athletes repeated twice a 10.5-km maximal run and ingested in a randomized single-blind order either 2.0 g vitamin C or placebo. In study II, eight athletes repeated twice a 27-km maximal run and ingested in randomly either 105 g carbohydrate or placebo. Venous blood samples were taken before the exercise, immediately after the exercise, and after a recovery period of 90 min (study I) or 120 min (study II). MEASURE: serum diene conjugation, lipid peroxidation. RESULTS: In study I, there was no difference in serum diene conjugation between the trials during exercise (pre- vs post-exercise). However, during the recovery period (post-exercise vs recovery sample) serum diene conjugation concentration decreased by 11% in the vitamin C trial but not in placebo (p = 0.028). In study II, there was no difference between the carbohydrate and placebo trials. CONCLUSIONS: Vitamin C and carbohydrate do not prevent exercise-induced increase in oxidative stress, but vitamin C, being a potent aqueous antioxidant, seems to decrease the levels of diene conjugation during recovery after exercise. The clinical significance of this phenomenon needs further evaluation.

Adult↗

PubMed1997

Antioxidant properties of the triphenylethylene antiestrogen drug toremifene.

The aim of the present study was to investigate antioxidativity of the triphenylethylene antiestrogen toremifene. Toremifene and its structural analogues were studied for their ability to inhibit chain reactions of lipid peroxidation and to act as scavengers of free radicals in vitro, and the effects of toremifene were compared to those of the estrogens, tamoxifen and known antioxidants. Moreover, the in vivo antioxidativity of toremifene was tested in a long-term experiment with rats. The ability of toremifene to prevent lipid peroxidation was assayed in two different test systems. In the first assay (initiated with ascorbate/ADP-FeCl3, detection by the formation of TBA-reactive material) toremifene was found to act as an efficient membrane antioxidant with an IC50-value (18 microM) comparable to that of tamoxifen (26 microM) and alpha-tocopherol (43 microM). Toremifene derivatives 4-hydroxytoremifene (IC50 = 8 microM) and Fc 1159 (IC50 = 31 microM), as well as diethylstilbestrol (IC50 = 17 microM) were also active while estradiol showed only weak antioxidativity (IC50 = 300 microM) in this test system. In the other assay (peroxidation initiated with t-butylhydroperoxide, detection by luminol-enhanced chemiluminescence) toremifene prevented lipid peroxidation only at high concentrations (IC50 = 450 microM) but the metabolite 4-hydroxytoremifene (IC50 = 0.18 microM), estradiol (IC50 = 4.6 microM) and diethylstilbestrol (IC50 = 1.7 microM) showed potent antioxidant activity. The potency of 4-hydroxytoremifene even exceded that of alpha-tocopherol (IC50 = 2.0 microM) and butylated hydroxyanisole (IC50 = 1.1 microM). Toremifene was found to have some superoxide anion but no peroxyl radical scavenging activity. Interestingly, diethylstilbestrol turned out to be a potent scavenger of peroxyl radicals. Treatment of female Sprague-Dawley rats with toremifene (12 or 48 mg/kg) was found to decrease serum levels of lipid peroxides. This was seen at various time points (2 days, 5 weeks, 6 and 12 months) during long-term administration of toremifene to rats, and results obtained with two different methods (diene conjugation, TBA-reactive material) gave similar results. The present study thus showed that (i) like steroidal estrogens and tamoxifen toremifene is a potent membrane antioxidant in vitro, (ii) the antioxidant action of toremifene is not due to scavenging of free radicals and, importantly, (iii) toremifene acts antioxidatively also in living organisms in vivo.

Animals↗

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

Regulation of copper/zinc and manganese superoxide dismutase by UVB irradiation, oxidative stress and cytokines.

We have examined the effects of UVB irradiation, oxidative stress and cytokines on the antioxidant enzymes copper/zinc and manganese superoxide dismutase (CuZnSOD and MnSOD) in HeLa cells. A single dose of UVB irradiation regulated dose-dependently the expression of the 4 kb transcript of MnSOD although it did not have any significant effect on MnSOD enzymatic activity. In contrast, UVB irradiation reduced both the enzymatic activity and the expression of the 0.7 and 0.9 kb mRNA transcripts of CuZnSOD. The cytokines TNF-alpha (1 ng ml-1 and 10 ng ml-1) and IL-6 (100 U ml-1) induced MnSOD activity, and TNF-alpha also upregulated MnSOD mRNA expression. Interestingly, genistein, a soy isoflavone and a tyrosine kinase inhibitor, was able to inhibit the induction of Mn-SOD activity and mRNA expression by TNF-alpha. Enzymatic CuZnSOD activity was depressed by a high dose of H2O2 while IL-6 or TNF-alpha had no effect on CuZnSOD activity. Our results demonstrate that, in addition to enzyme activity level, UVB irradiation can regulate the superoxide dismutases at the mRNA level. We also suggest that UVB irradiation, oxidative stress and cytokines regulate differentially CuZnSOD and MnSOD, and that the activities and expression of these antioxidant enzymes are controlled by distinct mechanisms.

Copper↗

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↗

PubMed1997

Human meconium has potent antioxidative properties.

In vitro the antioxidative capacity of pooled and lyophilized human meconium, measured by chemiluminescence, was compared to that of three potent antioxidants: vitamin C, a vitamin E analogue and a synthetic antioxidant, butylated hydroxytoluene. Meconium showed a significant superoxide trapping and peroxidation prevention capacity, but its capacity to trap peroxyl radicals was minor. These effects of meconium were possibly due to bilirubin and ubiquinol-10, both found in high concentrations in meconium. It is speculated that human meconium may have a physiological role as an important endogenous antioxidant during perinatal transition.

Antioxidants↗

PubMed1996

Simple methods of quantifying oxidation products and antioxidant potential of low density lipoproteins.

OBJECTIVES: The present study describes new methods for the measurement of oxidation products and antioxidant potential of low density lipoproteins (LDL). DESIGN AND METHODS: LDL is isolated by precipitation with buffered heparin. The assay for LDL oxidation products (LDL-BDC) is based on determination of baseline levels of conjugated dienes (BDC) in lipids extracted from LDL. The assay for antioxidant potential of LDL (LDL-TRAP) is based on the ability of LDL to trap peroxyl radicals. RESULTS: LDL-BDC was found to increase linearly over a range from 100 to 1750 microL, LDL-TRAP from 250 to 1750 microL of serum taken for precipitation. For LDL-BDC, the CV was 4.4% and 4.5% for within- and between-assay precision, respectively. For the LDL-TRAP, the CV was 8.1% and 8.7% for within- and between-assay precisions, respectively. Freezing of the serum (2 weeks at -70 degrees C) did not affect LDL-BDC or LDL-TRAP levels. A negative correlation was found to exist between the LDL-BDC and LDL-TRAP values. LDL-BDC and LDL-TRAP values were at the same level in both sexes. The LDL-BDC was found to increase with age. Short-term intervention with antioxidants increased LDL-TRAP substantially, but did not affect the LDL-BDC level. CONCLUSIONS: These methods are fast and simple to perform, and can, therefore, be applied to clinical purposes.

Adolescent↗

PubMed1996

Lipid peroxidation and antioxidants in normal and pre-eclamptic pregnancies.

Lipid peroxidation has been suggested as a pathogenetic factor of pre-eclampsia. In this study we measured lipid peroxidation products and the counteracting antioxidant functions in maternal serum and placental tissue in normal pregnancy and pre-eclampsia. Placentae and maternal serum from 15 normal and 15 pre-eclamptic pregnancies were collected. Lipid peroxidation was measured as peroxidation potential, thiobarbituric acid reacting substances (TBARS) and conjugated diene onuble bonds. The antioxidative capacity was measured as the activity of superoxide dismutase, glucose 6-phosphate-dehydrogenase, glutathione peroxidase and glutathione transferase and the concentration of placental vitamin E. Placental lipid peroxidation was higher in pre-eclampsia than in normal pregnancy, when measured by peroxidation potential and TBARS (P = 0.002 and P = 0.027, respectively). The activity of placental superoxide dismutase (P = 0.003) and glucose 6-phosphate-dehydrogenase (P = 0.019) was significantly lower in pre-eclampsia than in normal pregnancy. There were no significant differences in the activity of glutathione peroxidase, glutathione-S-transferase or vitamin E level between the study groups. The peroxyl radical trapping capacity (TRAP) was higher (P = 0.013) in the serum of pre-eclamptic than control patients. Lipid peroxidation is increased and the activity of antioxidant enzymes superoxide dismutase and glucose 6-phosphate-dehydrogenase are decreased in pre-eclamptic placenta. The TRAP is high in the serum of pre-eclamptic patients.

Adult↗

PubMed1996

Low LDL oxidation in veteran endurance athletes.

The 'oxidation hypothesis' states that oxidative modification of low-density lipoprotein (LDL) is important in the pathogenesis of the atherosclerotic lesion. Physical exercise has been reported to reduce clinical manifestations of atherosclerosis. We compared the effects of aerobic physical exercise history on oxidation characteristics of plasma LDL at rest in non-smoking male veteran endurance athletes (n= 15) and control subjects (n= 16). As an indicator of LDL oxidation we used a method which provides an estimate of LDL diene conjugation in vivo. The athletes had lower plasma LDL cholesterol diene conjugation (P=0.003). They also had lower cholesterol, lower LDL and higher high-density lipoprotein (HDL) cholesterol. Intensive physical exercise energy expenditure correlated inversely with LDL diene conjugation (r=-0.41, P= 0.021). We conclude that participation in intensive physical exercise training is associated with reduced plasma LDL fraction oxidation as reflected by LDL diene conjugation. This finding may have relevance for studies aiming to explain the variation in occurrence of ischemic heart disease.

Adult↗

PubMed1996

Induction of lipid peroxidation during steroidogenesis in the rat testis.

Free radical production and lipid peroxidation are potentially important mediators in testicular physiology and toxicology. The cytochrome P450 enzymes of the steroidogenic pathway are known to produce free radicals. The present study was conducted to elucidate in vivo the gonadotropin regulation of free radical-mediated lipid peroxidation and the antioxidative defense system in the rat testis. GnRH antagonist (Org 30276; 1 mg/kg BW) and testosterone [40-mm SILASTIC brand (Dow-Corning) capsules] treatments were used to suppress serum gonadotropin levels. As expected, serum LH decreased to a very low level, whereas serum FSH decreased only slightly. Testosterone treatment for 8 days decreased the levels of the peroxide-metabolizing enzymes, catalase, glutathione peroxidase (GSH-Px), and glutathione transferase (-44%, -24%, and -31%, respectively; P < 0.01 for all). These changes predominately reflect the interstitial tissue, in which catalase and GSH-Px activities were much higher than in the seminiferous tubules. Testicular CuZn or Mn superoxide dismutase activities, which were high in the seminiferous tubules, were not affected by gonadotropin suppression. The total peroxyl radical-trapping capacity of the testis, or its components, vitamin E and ubiquinol 9, were not affected either. Lipid peroxidation was decreased after 8-day treatment, as detected by diminished formation of conjugated dienes and fluorescent chromolipids (-30% and -19%, respectively; P < 0.05 for both). Similar results of decreasing catalase and GSH-Px activities were found after gonadotropin suppression with GnRH antagonist treatment for 2 days or testosterone treatment for 5 days. Substitution with hCG, alone or in combination with recombinant human FSH, reversed the changes in enzyme activities, whereas FSH alone had no effect. After 5-day testosterone treatment, catalase messenger RNA expression was studied by Northern hybridization, and it was observed to parallel the changes in enzyme activity. The site of free radical production was studied by separating interstitial tissue and seminiferous tubules 5 h after hCG injection. GSH-Px was induced by hCG only in the interstitial tissue (+28%; P< 0.01), supporting the hypothesis of free radical production during steroidogenesis. Aminoglutethimide, an inhibitor of the P450 cholesterol side-chain cleavage enzyme, induced extensive lipid peroxidation in the testis. Presumably, aminoglutethimide leads to leakage of free radicals from the P450 enzyme when substrate oxygenation is prevented. In conclusion, the present study suggests that physiological LH action in the rat testis causes lipid peroxidation and maintains high activities of peroxide-metabolizing enzymes in the interstitial tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Aminoglutethimide↗

PubMed1995

Measurement of serum lipid peroxidation during exercise using three different methods: diene conjugation, thiobarbituric acid reactive material and fluorescent chromolipids.

Serum lipid peroxidation was measured by three different methods (diene conjugation, DC; thiobarbituric acid reactive material, TBARM; and fluorescent chromolipids, FC) during physical exercise of different duration. The aim of the study was to investigate which of the three methods is the most representative in measuring oxidative stress after physiological stimulus (physical exercise) in man. In general, diene conjugation is a measure of early events of lipid peroxidation reactions, TBARM measures end products of lipid peroxidation and FC are products formed by reaction of end products of lipid peroxidation with the amino groups. In trial I, 8 subjects ran 1 km with maximal speed; in trial II, 7 subjects ran 10 km with maximal speed; in trial III, 9 subjects ran 27 km with maximal speed, and in trial IV, 5 subjects cycled 8 days in competition, altogether 1061 km biking. In each trial venous blood samples were taken before and immediately after the exercise. In trials II, III, and IV serum DC concentration increased by 14% (P < 0.05), 11% (P < 0.01), and 25% (P < 0.05), respectively, during the exercise. FC or TBARM did not change in the trials. We conclude that DC as a measure of the early phase of lipid peroxidation may be less affected by protective antioxidant functions than FC and TBARM methods, which both measure end products of lipid peroxidation. Therefore, DC may be the most sensitive of the three methods to estimate serum lipid peroxidation induced by exercise in man.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Antioxidant enzymes are elevated in dimethylbenz[a]anthracene-induced neoplastic murine keratinocytes containing an active rasHa oncogene.

Antioxidant enzyme activities and peroxidation potential were measured in primary mouse keratinocytes and neoplastic keratinocytes containing an active rasHa oncogene. In neoplastic cell lines, SP-1 and 308, the activities of Cu, Zn-superoxide dismutase, catalase, and glutathione transferase were significantly elevated. The peroxidation potential was lower in cell homogenates prepared from neoplastic keratinocytes than in those prepared from normal keratinocytes. Consistently, the neoplastic 308 cell line was found to be more resistant than the normal keratinocytes to cytotoxicity induced by UV-B irradiation. The present study suggests that the enhanced antioxidant defense system protects the initiated cells from UV-B-induced oxidative stress, and that the enhanced enzymic antioxidant defense system is potentially a mechanism favoring the selective growth of neoplastic keratinocytes.

9,10-Dimethyl-1,2-benzanthracene↗