Biomedical subjects

Reid Hayward

Publications and source records attributed to Reid Hayward.

4 recordsLinked to original sources

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

Attenuation of homocysteine-induced endothelial dysfunction by exercise training.

Hyperhomocysteinemia is an independent risk factor for the development of cardiovascular disease. Exposure of endothelial cells to elevated levels of homocysteine (HCY) results in decreased availability of nitric oxide (NO) and impaired vascular function, both of which are early events in atherogenesis. Exercise training improves vascular function by increasing endothelial NO production secondary to an increase in the enzyme responsible for its synthesis, endothelial nitric oxide synthase (eNOS). We hypothesized that exercise training would increase endothelial NO production, which would attenuate the endothelial dysfunction associated with HCY exposure. Rats were randomly assigned to either sedentary (SED) or exercise (EX) groups. The exercise regimen consisted of treadmill running at 20-25 m/min, 15% grade, 30 min/day, 5 day/week for 6 weeks. Aortic rings obtained from SED and EX trained rats were incubated with 2 mM HCY for 120 min, then exposed to norepinephrine (NE 100 nM) to induce vasoconstriction. Once a stable contraction plateau was achieved, rings were exposed to increasing concentrations of the receptor-mediated endothelium-dependent vasodilator acetylcholine (ACh; 0.1, 1, 10, 100 nM). This procedure was repeated with the non-receptor-mediated endothelium-dependent vasodilator A-23187 (0.1, 1, 10, 100 nM), and the endothelium-independent vasodilator, NaNO(2) (0.1, 1, 10, 100 muM). In addition, eNOS protein content and eNOS enzyme activity were determined. Aortic rings obtained from exercise trained rats demonstrated significantly (P<0.05) greater relaxation to both ACh and A-23187 in comparison to aortic rings obtained from SED rats following exposure to HCY. Additionally, exercise training increased aortic eNOS protein content and activity. Our data demonstrate that exercise training improves endothelium-dependent vasorelaxation following HCY exposure and this may be due, at least in part, to elevated levels of eNOS protein and an increase in eNOS activity. These results suggest the possible role exercise may play in attenuating the endothelial dysfunction associated with hyperhomocysteinemia.

Journal Article↗

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↗