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In JoVE (1)
Other Publications (12)
- Journal of Applied Physiology (Bethesda, Md. : 1985)
- Medicine and Science in Sports and Exercise
- Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquée, Nutrition Et Métabolisme
- Journal of Strength and Conditioning Research / National Strength & Conditioning Association
- The Journal of Clinical Endocrinology and Metabolism
- Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquée, Nutrition Et Métabolisme
- Frontiers in Bioscience (Elite Edition)
- European Journal of Applied Physiology
- Advances in Physiology Education
- Clinics (São Paulo, Brazil)
- European Journal of Applied Physiology
- Clinics (São Paulo, Brazil)
Articles by James Navalta in JoVE
JoVE Immunology and Infection
Finger-stick Blood Sampling Methodology for the Determination of Exercise-induced Lymphocyte Apoptosis
1Department of Kinesiology, Recreation, and Sport, Western Kentucky University, 2Department of Health and Human Performance, University of Houston
Exercise is capable of inducing apoptosis in immune cells. There are various measurement limitations, particularly relating to the amount of time required to isolate and treat a blood sample prior to the assessment. Demonstrated is a rapid and minimally invasive procedure for the analysis of exercise-induced lymphocyte apoptosis.
Other articles by James Navalta on PubMed
Carbohydrate Loading and Supplementation in Endurance-trained Women Runners
The purpose of this study was to examine the effect of carbohydrate (CHO) augmentation on endurance performance and substrate utilization in aerobically trained women. Eight endurance-trained women completed a 24.2-km (15 mile) self-paced treadmill performance run under three conditions: CHO supplementation (S), CHO loading and supplementation (L+S), and placebo (P). Dietary CHO was approximately 75% of energy intake for L+S and approximately 50% for both S and P. A 6% CHO-electrolyte solution (S and L+S) or placebo (P) was ingested preexercise (6 ml/kg) and every 20 min during exercise (3 ml/kg). Blood glucose was significantly higher at 40, 60, and 100 min during L+S, and at 60, 80, and 100 min during S compared with P (P < 0.05). Blood lactate was significantly higher (P < 0.05) during L+S than S and P. Blood glycerol was significantly lower (P < 0.05) at 20, 80, and 100 min during L+S, and at 80 and 100 min during S than P. The proportion of CHO (%) utilized during exercise was significantly higher (P < 0.05) during L+S (71.3 +/- 3.8%) and S (67.3 +/- 4.3%) than P (59.2 +/- 4.6%). Performance times (P > 0.05) were 132.5 +/- 6.3 min (S), 134.4 +/- 6.3 min (L+S), and 136.6 +/- 7.9 min (P). In conclusion, it appears that when CHO availability in women is increased through CHO loading and/or CHO supplementation, there is a concomitant increase in CHO utilization. However, this may not necessarily result in significantly improved performance.
Blood Treatment Influences the Yield of Apoptotic Lymphocytes After Maximal Exercise
No systematic investigation has been reported assessing the effect of cell isolation processes on postexercise apoptosis. Therefore, the effect of cell isolation procedures on apoptosis was evaluated in this study.
Neither Gender nor Menstrual Cycle Phase Influences Exercise-induced Lymphocyte Apoptosis in Untrained Subjects
Lymphocyte apoptosis increases following maximal exercise. Estrogen hormones (E2) have been shown to protect lymphocytes from apoptosis in vitro, but it is unknown whether they can attenuate the apoptotic response to maximal exercise. The purpose of this study was to examine the effect of menstrual cycle variation on exercise-induced lymphocyte apoptosis in humans following exercise. Untrained healthy young men and regularly menstruating women not using hormonal contraceptives volunteered for the study. Women performed a maximal effort treadmill test for VO2 max once in the follicular phase (FOL) and once in the mid-luteal phase (ML) of their cycles. Men completed two VO2 max tests with periods of time between tests matched to those of the female subjects. Blood was collected before (PRE) and immediately after exercise (POST), and analyzed for apoptotic lymphocytes and estradiol. E2 concentrations in women were significantly greater during ML versus during FOL, both PRE and POST (p<0.0001). The percent of exercise-induced lymphocyte apoptosis was similar between women (23.2%+/-1.0%) and men (21.5%+/-0.4%). In women, the apoptotic response to maximal exercise was similar regardless of menstrual cycle phase (FOL=23.7%+/-0.9%, ML=22.7%+/-1.1%). Although elevated female sex hormones in vitro may exert anti-apoptotic effects, these data suggest that in vivo concentrations confer no protection to lymphocytes during exhaustive exercise.
Core Stabilization Exercises Enhance Lactate Clearance Following High-intensity Exercise
Dynamic activities such as running, cycling, and swimming have been shown to effectively reduce lactate in the postexercise period. It is unknown whether core stabilization exercises performed following an intense bout would exhibit a similar effect. Therefore, this study was designed to assess the extent of the lactate response with core stabilization exercises following high-intensity anaerobic exercise. Subjects (N = 12) reported twice for testing, and on both occasions baseline lactate was obtained after 5 minutes of seated rest. Subjects then performed a 30-second Wingate anaerobic cycle test, immediately followed by a blood lactate sample. In the 5-minute postexercise period, subjects either rested quietly or performed core stabilization exercises. A final blood lactate sample was obtained following the 5-minute intervention period. Analysis revealed a significant interaction (p = 0.05). Lactate values were similar at rest (core = 1.4 +/- 0.1, rest = 1.7 +/- 0.2 mmol x L(-1)) and immediately after exercise (core = 4.9 +/- 0.6, rest = 5.4 +/- 0.4 mmol x L(-1)). However, core stabilization exercises performed during the 5-minute postexercise period reduced lactate values when compared to rest (5.9 +/- 0.6 vs. 7.6 +/- 0.8 mmol x L(-1)). The results of this study show that performing core stabilization exercises during a recovery period significantly reduces lactate values. The reduction in lactate may be due to removal via increased blood flow or enhanced uptake into the core musculature. Incorporation of core stability exercises into a cool-down period following muscular work may result in benefits to both lactate clearance as well as enhanced postural control.
Predictors of Calcium Retention in Adolescent Boys
The relationship between calcium (Ca) intake and Ca retention in adolescent boys was recently reported.
Exercise-induced Lymphocyte Apoptosis Attributable to Cycle Ergometer Exercise in Endurance-trained Individuals
Exercise as a stimulus to induce lymphocyte apoptosis remains controversial. Differences may be due to participant fitness level or the methodology of assessing cell death. Another important issue is the mode of exercise used to induce physiological changes. Treadmill exercise typically induces significant apoptosis in human lymphocytes; however, the effect of cycle exercise is less clear. The 2 main purposes of this study were to assess if cycle ergometer exercise induces similar changes in apoptosis, and to further characterize the morphological method of assessing cell death. Endurance athletes (n = 10; peak oxygen consumption = 55.1 mL.kg-1.min-1) completed a 60-min ride on a cycle ergometer at approximately 80% peak oxygen consumption. Blood samples taken before (PRE) and after (POST) exercise were used to make blood films for apoptotic analysis via the morphological technique. A significant increase was observed in the apoptotic index following cycle exercise (PRE = 7.3 +/- 2%, POST = 12.9 +/- 2%; p < 0.01). On average, it took 42 +/- 9 min to read PRE sample slides, which was significantly longer than the 27 +/- 4 min needed for POST slides (p < 0.01). To our knowledge, this study is the first to report that exercise on the cycle ergometer produces changes in lymphocyte apoptosis. The values measured during this study were about 20% lower than those we have observed following treadmill running, which may be explained by differences in active muscle mass and the resultant physiological stress between the 2 exercise modes. It is likely that cycling may result in reduced immunosuppression, compared with running at the same intensity.
Does Exercise Really Induce Lymphocyte Apoptosis?
While the stress associated with acute exercise has been reported to induce significant lymphocyte apoptosis, not all investigations have confirmed this finding. Regardless of animal or human subjects, exercise-induced lymphocyte apoptosis may be induced via an external receptor-mediated pathway, or internally via the mitochondria through an oxidative-mediated pathway. On the other hand, investigators reporting no effect of acute exercise on lymphocyte apoptosis speculate that cell death may be dissociated from these pathways, and explain exercise lymphocytopenia by selective migration of the lymphocytes back into the lymphoid pools. Discrepancies may be due to sensitivity issues related to the methodology used to assess cell death. Limitations to various methods used to evaluate exercise-induced lymphocyte apoptosis are detailed, and considerations for a new technique are outlined.
Exercise-induced Immune Cell Apoptosis: Image-based Model for Morphological Assessment
Methods of assessing exercise-induced lymphocyte apoptosis have produced varying results. While morphological methods generally yield a significantly greater apoptotic index compared to those employing biochemical markers, benefits and limitations are associated with each methodology. Of interest in this report is the limitation of subjectivity associated with the morphological technique. To overcome the lack of objectivity associated with the morphological method, we describe an image-based approach by which computer software assesses the characteristics associated with lymphocyte apoptosis. A stochastic controlled deformable model can be employed to detect the classic morphological apoptotic changes induced by exercise, including membrane blebbing and the formation of apoptotic bodies. We propose that an objective evaluation of multiple points in the apoptotic process through the proposed model in conjunction with current biomarker methods has the potential to advance our understanding of the exercise-induced immune cell death response to a greater degree than current methods.
Student Peer Review Decisions on Submitted Manuscripts Are As Stringent As Faculty Peer Reviewers
The International Journal of Exercise Science is the only student-centered peer-reviewed journal in its field. Upon graduate student first author submissions, two student reviewers and one faculty reviewer are asked to review. On professionally submitted papers, two faculty peers are asked to assess the manuscript. The purpose of the present study was to determine whether graduate students returned similar decisions compared with faculty reviewers who evaluated the same manuscript. In addition, decisions of faculty peers reviewing graduate student- versus faculty-submitted manuscripts were compared. Mean comparisons between groups were evaluated using independent t-tests with significance at P ≤ 0.05. Graduate students (2.21 ± 0.69) and faculty peers (2.24 ± 0.66) returned similar decisions on student-submitted manuscripts (P = 0.84). Faculty decisions on manuscripts submitted by a professional primary author (1.86 ± 0.77) were not different compared with faculty peers reviewing student manuscripts (P = 0.06). Statistics revealed that graduate students are just as stringent in the peer review process as established reviewers. Additionally, faculty reviewers evaluated manuscripts equally regardless of submission type.
Phagocytic Responses of Peritoneal Macrophages and Neutrophils Are Different in Rats Following Prolonged Exercise
To analyze the effects of exhausting long-duration physical exercise (swimming) sessions of different durations and intensities on the number and phagocytic capacity of macrophages and neutrophils in sedentary rats.
Leukocyte Apoptosis and Pro-/anti-apoptotic Proteins Following Downhill Running
The purposes of this study were to determine the effect of eccentric exercise-induced muscle damage on the induction of apoptosis in peripheral blood leukocytes and to investigate if the elevation in apoptotic leukocytes was mediated by changes in the concentration of anti-/pro-apoptotic proteins in circulation. Twelve moderately trained subjects performed three 40 min treadmill runs at ~70% VO(2max): a level run (L) followed by two downhill runs (DH1 and DH2). Blood samples were taken at rest (PRE) and immediately (POST), 2, 24, and 48 h after each run. Data were analyzed using two-way repeated measures analysis of variance with post hoc Tukey tests. Creatine kinase (CK) activity was significantly elevated at 24 and 48 h following DH1 (P < 0.01). The proportion (%) of apoptotic leukocytes was significantly elevated at POST and 2 h following all three runs, and up to 48 h following DH1 (P < 0.01). Bax at 24-h post and Bax/Bcl-2 ratio at 24- (P < 0.01) and 48-h post (P < 0.05) following DH1 were greater than PRE (P < 0.05). An acute bout of moderate intensity downhill running altered CK activity, Bax concentration and the Bax/Bcl-2 ratio in circulating leukocytes resulting in a greater apoptotic response at 24- and 48-h post-exercise compared to level grade running or a second downhill run. Although the mechanism by which these proteins are altered by unaccustomed eccentric exercise is currently unknown, the differential response to DH1 versus L and DH2 indicates that it may be related to exercise-induced muscle damage.
Cognitive Awareness of Carbohydrate Intake Does Not Alter Exercise-induced Lymphocyte Apoptosis
The purpose of this investigation was to determine whether cognitive awareness of carbohydrate beverage consumption affects exercise-induced lymphocyte apoptosis, independent of actual carbohydrate intake.
