Biomedical subjects

Carole M Schneider

Publications and source records attributed to Carole M Schneider.

8 recordsLinked to original sources

PubMed2006

Exercise training attenuates acute doxorubicin-induced cardiac dysfunction.

The use of doxorubicin, a highly effective antitumor antibiotic, is limited by a dose-dependent cardiotoxicity. The purpose of this study was to determine whether chronic exercise training (ET) prior to doxorubicin treatment would preserve cardiac function and reduce myocardial oxidative stress following treatment. Rats were exercise trained on a motorized treadmill or confined to sedentary cage activity for 12 weeks, then administered an intraperitoneal injection of doxorubicin (15 mg/kg) or 0.9% saline. Five days following the injections, hearts were isolated and Langendorf perfused to assess cardiac function and then processed for biochemical analyses. Doxorubicin treatment induced significant inotropic, lusitropic, and chronotropic cardiac dysfunction, reduced coronary flow, and increased cardiac lipid peroxidation in the sedentary animals. Doxorubicin treatment was also associated with a decrease in cardiac manganese superoxide dismutase protein expression and an increase in heat shock protein-72 (Hsp72) compared with saline-treated animals. Exercise training attenuated doxorubicin-induced cardiac dysfunction, and lipid peroxidation, and led to a greater cardiac expression of Hsp72 compared with the sedentary animals. The results of this study demonstrate for the first time that chronic exercise training before doxorubicin treatment protects against cardiac dysfunction following treatment, and provide evidence for a sustained increase in myocardial Hsp72 following exercise training and doxorubicin treatment in vivo.

Animals↗

PubMed2005

Low-intensity exercise training during doxorubicin treatment protects against cardiotoxicity.

Doxorubicin (Dox) is a highly effective antineoplastic antibiotic associated with a dose-limiting cardiotoxicity that may result in irreversible cardiomyopathy and heart failure. The purpose of this study was to examine the effects of low-intensity exercise training (LIET) during the course of Dox treatment on cardiac function, myosin heavy chain expression, oxidative stress, and apoptosis activation following treatment. Male Sprague-Dawley rats either remained sedentary or were exercise trained on a motorized treadmill at 15 m/min, 20 min/day, 5 days/wk (Monday through Friday) for 2 wk. During the same 2-wk period, Dox (2.5 mg/kg) or saline was administered intraperitoneally to sedentary and exercised rats 3 days/wk (Monday, Wednesday, Friday) 1-2 h following the exercise training sessions (cumulative Dox dose: 15 mg/kg). Five days following the final injections, hearts were isolated for determination of left ventricular (LV) function, lipid peroxidation, antioxidant enzyme protein expression, 72-kDa heat shock protein expression, caspase-3 activity, and myosin heavy chain isoform expression. Dox treatment significantly impaired LV function and increased caspase-3 activity in sedentary animals (P < 0.05). LIET attenuated the LV dysfunction and apoptotic signal activation induced by Dox treatment and increased glutathione peroxidase expression, but it had no significant effect on lipid peroxidation, protein expression of myosin heavy chain isoforms, 72-kDa heat shock protein, or superoxide dismutase isoforms. In conclusion, our data suggest that LIET applied during chronic Dox treatment protects against cardiac dysfunction following treatment, possibly by enhancing antioxidant defenses and inhibiting apoptosis.

Animals↗

PubMed2005

Voluntary exercise protects against acute doxorubicin cardiotoxicity in the isolated perfused rat heart.

The clinical use of doxorubicin (DOX) is limited by a dose-dependent cardiotoxicity. The purpose of this study was to determine whether voluntary exercise training would confer protection against DOX cardiotoxicity in the isolated perfused rat heart. Female Sprague-Dawley rats were randomly assigned to standard holding cages or cages with running wheels for 8 wk. Twenty-four hours after the sedentary (SED) or voluntary exercise (VEX) running period, rats were anesthetized with pentobarbital sodium, and hearts were isolated and perfused with oxygenated Krebs-Henseleit (KH) buffer at a constant flow of 15 ml/min. After a 20-min stabilization period, hearts were paced at 300 beats per minute and perfused with KH buffer containing 10 microM DOX for 60 min. A set of control hearts from SED and VEX rats were perfused under identical conditions without DOX for the same period. DOX perfusion led to significant decreases in left ventricular developed pressure, +dP/dt, and -dP/dt, and significant increases in LV lipid peroxidation in sedentary rats compared with non-DOX controls (P < 0.05). Prior voluntary exercise training attenuated these DOX-induced effects and was associated with a significant increase (78%, P < 0.05) in heat shock protein (HSP72), but not mitochondrial isoform of SOD (MnSOD) or CuZnSOD protein expression in the hearts of wheel-run animals. These data indicate that chronic physical activity may provide resistance against the cardiac dysfunction and oxidative damage associated with DOX exposure and provide novel evidence of HSP72 induction in the heart after voluntary exercise.

Animals↗

PubMed2005

The relationship between physical activity and 2-hydroxyestrone, 16alpha-hydroxyestrone, and the 2/16 ratio in premenopausal women (United States).

OBJECTIVES: Estrogen is metabolized in the body through two mutually exclusive pathways yielding metabolites with different biological activities: the low estrogenic 2-hydroxyestrone (2-OHE1) and the highly estrogenic 16alpha-hydroxyestrone (16alpha-OHE1). The ratio of these metabolites (2/16) may be predictive of risk for developing breast cancer. Early evidence has demonstrated that exercise may alter estrogen metabolism to favor the weak estrogen, 2-OHE1. METHODS: Seventy-seven eumenorrheic females completed physical activity logs for two weeks prior to providing a luteal phase urine sample. Concentrations of 2-OHE1 and 16alpha-OHE1 were measured and the 2/16 ratio computed. Hierarchical regression, controlling for age and body mass index (BMI), was used to determine relationships between estrogen metabolites and daily physical activity. RESULTS: Regression analyses indicated significant positive relationships between physical activity and 2-OHE1 and the 2/16 ratio (p < 0.05) that appears to be independent of BMI. 16alpha-OHE1 was not significantly related to physical activity. CONCLUSION: These results indicate that physical activity may modulate estrogen metabolism to favor the weak estrogen, 2-OHE1, thus producing a higher 2/16 ratio. This alteration in estrogen metabolism may represent one of the mechanisms by which increased physical activity reduces breast cancer risk.

Adolescent↗

PubMed2005

The effects of walking poles on shoulder function in breast cancer survivors.

Breast cancer treatment often results in impaired shoulder function, in particular, decrements in muscular endurance and range of motion, which may lead to decreased quality of life. The purpose of this investigation was to determine the effects of walking pole use on shoulder function in female breast cancer survivors. Participants had previously been treated with 1 or a combination of the following: mastectomy, breast conservation therapy, axillary lymph node dissection, chemotherapy, or radiation. Participants were randomly placed in experimental (n = 6) and control (n = 6) groups and met with a cancer exercise specialist 2 times each week for 8 weeks. The experimental group used walking poles during the 20-minute aerobic portion of their workout, whereas the control group did not use walking poles but performed 20 minutes of aerobic exercise per workout session. Both groups participated in similar resistance training programs. Testing was done pre- and postexercise intervention to determine upper body muscular endurance and active range of motion at the glenohumeral joint. Repeated-measures analysis of variance (ANOVA) revealed significant improvements in muscular endurance as measured by the bench press (P = .046) and lat pull down (P = .013) in the walking pole group. No within-group improvements were found in the group that did not use walking poles. The data suggest that using a walking pole exercise routine for 8 weeks significantly improved muscular endurance of the upper body, which would clearly be beneficial in helping breast cancer survivors perform activities of daily living and regain an independent lifestyle.

Activities of Daily Living↗

PubMed2004

Training enhances vascular relaxation after chemotherapy-induced vasoconstriction.

PURPOSE: Although evidence is accumulating that suggests regular moderate physical activity improves physiological and psychological well-being of cancer patients undergoing chemotherapy, the mechanisms involved remain unclear. Therefore, the purpose of this study was to determine if exercise training improves endothelium-dependent vasodilation after exposure to the chemotherapeutic agent 5-fluorouracil (5-FU). METHODS: Rats were injected with N-methyl-N-nitrosourea (MNU) and assigned to either exercise (EX; treadmill running, 20-25 m.min(-1) grade, 30 min.d(-1), 5 d.wk(-1) for 8 wk) or sedentary (SED) groups. After the exercise training period, aortic rings were obtained and used to assess contractile and relaxation characteristics. In addition, endothelial nitric oxide synthase (eNOS) protein content and eNOS enzyme activity was determined. RESULTS: Exercise training resulted in increased maximal endothelium-dependent vasorelaxation to acetylcholine (ACh, 1 x 10(-5) M) (SED, 56 +/- 3%; exercise, 71 +/- 5%; P < 0.05) after norepinephrine-induced (1 x 10(-7) M) vasoconstriction. Exposure of aortic rings from each group to increasing concentrations of 5-FU (7 x 10(-5) x 10 M(-3)) resulted in vasoconstriction. Rings obtained from exercise-trained animals demonstrated enhanced vasorelaxation to ACh (1 x 10(-5) M) after 5-FU-induced vasoconstriction compared with rings obtained from SED animals (P < 0.05). In addition, exercise training enhanced eNOS protein content and eNOS activity. CONCLUSION: Exercise training enhances endothelium-dependent vasorelaxation after 5-FU-induced vasoconstriction, and this may be due, at least in part, to an increase in aortic eNOS protein content and activity. Such exercise-induced adaptations may help alleviate chemotherapy-related fatigue observed in cancer patients.

Animals↗

PubMed2003

Influence of acute resistance exercise on cardiac biomarkers in untrained women.

This study was conducted to determine if an initial bout of resistance (weight lifting) exercise by untrained women results in any alterations in indicators of acute myocardial infarction (AMI). Untrained women performed 4 resistance exercises at 70% of their 1 repetition maximum. Blood samples were obtained during the 12 h post-exercise and analyzed for total creatine kinase (CK)-MB, CK-MB subforms 1 and 2, and the relative lymphocyte percentage. Exercise resulted in significant increases in total CK-MB, CK-MB(1), CK-MB(2), and the CK-MB(2)/CK-MB(1) ratio, total leukocyte count, and lymphocyte count. Using several criteria for the assessment of AMI, 22-25% of subjects completing the protocol demonstrated increases in CK-MB(2), CK-MB(2)/CK-MB(1) ratio, and relative lymphocyte percentages that were suggestive of AMI. Thus, our data suggest that moderate resistance exercise can significantly alter blood indicators of AMI, emphasizing the need to determine recent exercise history in patients with possible AMI.

Adult↗

PubMed2003

A case study: prescriptive exercise intervention after bilateral mastectomies.

Exercise for cancer patients is gaining support. In the current case study, a female breast cancer patient was diagnosed with breast cancer at the age of 29 years; she underwent a left modified radical mastectomy. She developed cancer again in the opposite breast at the age of 57 years and had a right modified radical mastectomy. After the second mastectomy (the right breast), the patient received chemotherapy and radiation. Following her cancer treatments, she participated in an exercise intervention for 6 months at the University of Northern Colorado's Rocky Mountain Cancer Rehabilitation Institute. A 6-month reassessment showed that she increased her muscular strength and cardiovascular function in addition to attenuating her cancer-related fatigue and depression. It is recommended that health professionals work together to ensure that a collaborative effort is undertaken to increase functional work capacity that will significantly improve patients' quality of life.

Adult↗