Helaine M. Alessio

EXERCISE INDUCED OXIDATIVE STRESS

The role of exercise in free radical processes is not clear; however, recent evidence suggests that elevated oxygen consumption may increase free radical activity. Direct measurement of free radical signals can be made by electron spin resonance and indirect measures include mitochondrial membrane damage, conjugated dienes, hydroperoxides, thiobarbituric acid reactive substances, short chain hydrocarbons, and oxidized nucleosides. Although exact levels are not known, the type, duration, and intensity of exercise affect biomarkers of free radical activity, as does ones training status. Oxidative stress associated with exercise-induced free radical activity seems to be better tolerated by trained subjects exercising at moderate intensity.

Generation of reactive oxygen species after exhaustive aerobic and isometric exercise

UNLABELLED Many studies have implicated elevated oxygen consumption (VO2) associated with aerobic exercise as contributing to oxidative stress. Only a few studies have investigated nonaerobic exercise and its relation to pro-oxidant and antioxidant activities. PURPOSE The purpose of this study was to compare biomarkers of oxidative stress: lipid peroxidation, protein oxidation, and total antioxidants in blood after exhaustive aerobic (AE) and nonaerobic isometric exercise (IE). METHODS Blood samples were collected from 12 subjects who performed a maximum AE and IE test and were analyzed for thiobarbituric acid (TBARS), carbonyls, lipid hydroperoxides (LH), and oxygen radical absorbance capacity (ORAC). RESULTS VO2 increased 14-fold with AE compared with 2-fold with IE. Protein carbonyls increased 67% (P < 0.05) pre- to immediately and 1 h post-AE, and 12% pre- to immediately post-IE and returned to baseline 1 h post-IE. TBARS did not increase significantly with either treatment. LH increased 36% above rest during IE compared with 24% during AE (P < 0.05). ORAC increased 25% (P < 0.05) pre- to post-AE, compared with 9% (P < 0.05) pre- to post-IE. CONCLUSION There was evidence of oxidative stress after both exhaustive aerobic and isometric exercise. Lipid hydroperoxides, protein carbonyls, and total antioxidants increased after both IE and AE. Due to the different metabolic demands of aerobic and isometric exercise, we can rule out a mass action effect of VO2 as the sole mechanism for exercise-induced oxidative stress.

Anti-angiogenic property of edible berries

Recent studies show that edible berries may have potent chemopreventive properties. Anti-angiogenic approaches to prevent and treat cancer represent a priority area in investigative tumor biology. Vascular endothelial growth factor (VEGF) plays a crucial role for the vascularization of tumors. The vasculature in adult skin remains normally quiescent. However, skin retains the capacity for brisk initiation of angiogenesis during inflammatory skin diseases such as psoriasis and skin cancers. We sought to test the effects of multiple berry extracts on inducible VEGF expression by human HaCaT keratinocytes. Six berry extracts (wild blueberry, bilberry, cranberry, elderberry, raspberry seed, and strawberry) and a grape seed proanthocyanidin extract (GSPE) were studied. The extracts and uptake of their constituents by HaCaT were studied using a multi-channel HPLC-CoulArray approach. Antioxidant activity of the extracts was determined by ORAC. Cranberry, elderberry and raspberry seed samples were observed to possess comparable ORAC values. The antioxidant capacity of these samples was significantly lower than that of the other samples studied. The ORAC values of strawberry powder and GSPE were higher than cranberry, elderberry or raspberry seed but significantly lower than the other samples studied. Wild bilberry and blueberry extracts possessed the highest ORAC values. Each of the berry samples studied significantly inhibited both H 2 O 2 as well as TNF f induced VEGF expression by the human keratinocytes. This effect was not shared by other antioxidants such as f -tocopherol or GSPE but was commonly shared by pure flavonoids. Matrigel assay using human dermal microvascular endothelial cells showed that edible berries impair angiogenesis.

Physical Activity as a Natural Antioxidant Booster and its Effect on a Healthy Life Span

The recent Surgeon Generals report (U.S. Department of Health and Human Services, 1996) promotes regular physical activity to enhance health. A possible mechanism by which physical activity contributes to a healthy life span is via enhanced antioxidant status. The purpose of this paper is to summarize findings from human studies on life span, health, antioxidants, and the effectiveness of physical activity as a natural antioxidant booster. Epidemiological studies concur that some antioxidants are inversely related to mortality. A single bout of exercise elevates some antioxidant enzyme and coenzyme activities. Regular physical activity enhances some antioxidants; however, strenuous exercise may diminish others. Results generally show that antioxidants play a mediating role in the way in which physical activity positively affects a healthy life span.

Exercise-induced changes in cardiac gene expression and its relation to spatial maze performance.

Cognitive performance is sensitive to both neural and non-neural changes induced by physical activity and inactivity. This study investigated whether access to physical activity outside a standard laboratory animal cage affected cognitive performance as measured by navigation of a spatial maze. It also examined gene expression in heart tissue for genes associated with cardiovascular function given recent reports of cognitive impairment associated with hyperlipidemia. Furthermore, we measured expression of neural-regulatory genes typically expressed in brain, but also found in cardiac tissue. Male Sprague-Dawley rats (n = 72) were separated into three groups having different access to physical activity: none outside a standard cage, twice-weekly physical activity, and every other day exercise on a running wheel. Compared with a sedentary group, spatial maze performance was enhanced in animals that had access to physical activity, either twice-weekly in a large box or every other day on a running wheel. Both the cardiovascular and neural-related genes expressed in the heart were distinguished by access to physical activity. Several genes that are associated with heart rate, cholesterol biosynthesis, blood pressure, and cell adhesion regulation, including GJA1, FDFT1, EDN1, and CD36, differed in animals based on access to physical activity. Neural-related genes expressed in cardiac tissue associated with neurite outgrowth, neuroplasticity, and neurogenesis including RTN4, HOMER2, ACTB, NCDN, KIF5B, and HMGB2, were expressed differently among the three groups. Significant shifts in ten cardiovascular and neural-related gene expressions in cardiac tissue were associated with physical activity and may have influenced learning and performance on a spatial maze.

Consumption of green tea protects rats from exercise-induced oxidative stress in kidney and liver

Abstract The effects of green tea on biomarkers of exercise-induced oxidative status were measured in young male Sprague-Dawley rats. Rats (n = 12) drank green tea or water ad lib for 6.5 weeks. Half of each group was sacrificed at rest, and the other half ran 25 m/min at 0% grade for approximately 30 min immediately before sacrifice. Green tea had no effect on resting heart rate, blood pressure, body weight, cholesterol, or triglycerides. Tea consumption had a mild influence on total plasma antioxidants, heart glutathione, and plasma ascorbic acid. Exercise had a major impact on malonaldehyde (MDA) equivalents in kidney (+290%, p = 0.0001), and to a lesser extent, liver (+81%, p = 0.18) in rats that drank water. In contrast, kidney MDA equivalents were unchanged by exercise in rats that drank green tea. Green tea may have selective protective effects within the body, especially on the kidney.

Exercise improves biomarkers of health and stress in animals fed ad libitum

Voluntary and forced exercise decrease morbidity and mortality in laboratory animals. Caloric restriction has similar effects on health and unique benefits on life span. Nonetheless, in most experiments, animals do not have access to physical activity and are fed ad libitum (AL). We hypothesized that with regular access to either unlimited running wheel exercise (EX) or limited physical activity (PA), key biomarkers of health would be enhanced enough to counter some consequences of a sedentary AL lifestyle. This 16-month study compared body weight, tumor number and size, tissue lesions, oxidative stress, and reactive stress in (1) sedentary animals with no access to physical activity (SED); (2) animals with access to hour-long, twice weekly activity in a large box (PA); and (3) animals with access every other day to a running wheel (EX). At the end of the study, EX body weight was 8-9% lower than PA and SED. In addition, EX had no kidney lesions versus 50% in PA and SED, and had smaller tumor size (10+/-2 vs. 14+/-4 and 30+/-4 mm). Exhaustive exercise lowered glutathione/oxidized glutathione ratio in EX and PA, but in SED, the ratio was depressed even in resting animals. In all treatments, prolactin (PRL) levels were lower in resting animals than in acutely exercised animals. In conclusion, EX had the most favorable health biomarkers while SED had the least. PA did not confer gross health benefits different than the SED group, but was biochemically more similar to EX animals.

Effects of Submaximal Exercise and Noise Exposure on Hearing Loss

A recent Scandinavian study reported that persons cycling at moderate intensity for 10 min suffered hearing loss when the exercise was accompanied by noise. The noise consisted of a 1/3 octave band-filtered noise with a 2000 Hz center frequency at 104 dB SPL. In the present study, adults cycled at 50 rev.min-1 against a force that elicited an oxygen cost equal to 70% of VO2max--an intensity frequently recommended in exercise prescriptions--with and without noise administered via headphones. Repeated measures ANOVA with three factors revealed that although a temporary hearing loss occurred following exercise-and-noise, a similar and slightly greater hearing loss occurred following noise-only. Hearing sensitivity was not significantly altered by exercise-only (p greater than .05). In general, hearing loss values were greatest between 3000 and 4000 Hz. In conclusion, temporary hearing loss was driven by noise exposure, not exercise. However, persons who choose to exercise with personal headphones or in a noisy environment should be aware of potential premature hearing loss.

Effects of Exercise Training on Hearing Ability

This study was designed to determine whether improvements in both cardiovascular fitness and hearing sensitivity occurred following 2 months of aerobic exercise training. Seventeen moderately-low fit (VO2 peak <32 ml/kg/min) young adults were evaluated for cardiovascular fitness and pure-tone and temporary threshold shifts (TTS) at 2, 3, and 4 kHz before and following 10 min of noise. Subjects exercised for 8 weeks by cycling on a bicycle ergometer at 70% of their peak oxygen consumption (VO2 peak). Average VO2 peak increased 34% (p < 0.05) above pre-exercise training levels. Both pure-tone hearing (2 and 3 kHz) and TTS improved following 2 months of exercise training at the evaluated frequencies (2, 3, and 4 kHz) (p < 0.05). Cardiovascular health as indicated by VO2 peak was associated with hearing sensitivity. Although the mechanisms have not been identified, these results support the existence of a cardiovascular health-hearing synergism.

Student Perceptions About and Performance in Problem-Based Learning

Over the last 30 years, international business opportunities have become more widespread. This rise in global business opportunities has not gone unnoticed by missiologists, and the development of the Business as Mission (BAM) movement has introduced a new realm of possibilities of linking business and mission. One potential weakness of this model is that international business managers often do not receive any missiological or theological training. It is likely that they receive less prayer support, less in-the-field support, and probably weaker moral accountability. As a result, many may be unaware of the some of the difficulties that they may face on international business assignments. This paper suggests that if Christian business faculty actively encourage students to explore international business opportunities, then they must sensitize students to some of the physical, emotional, and spiritual challenges that they may face on overseas business assignments. The last section of the paper shows how these challenges and realities of international business can be introduced in the classroom through an innovative use of Sofia Coppolo’s 2003 movie Lost in Translation. The final section offers some concluding remarks followed by an appendix presenting a scene-by-scene analysis of Lost in Translation.