The roles of the mode of contraction (i.e., dynamic or static) and the active muscle mass as determinants of the cardiovascular responses to exercise were studied. Six healthy men performed static handgrip (SHG), dynamic handgrip (DHG), static two-knee extension (SKE), and dynamic two-knee extension (DKE) to local muscular fatigue in approximately 6 min. Increases in mean arterial pressure were similar for each mode of contraction, 29 +/- 5 and 30 +/- 3 mmHg in SHG and DHG and 56 +/- 2 and 48 +/- 2 mmHg in SKE and DKE (P greater than 0.05) but larger for KE than HG (P less than 0.001). Cardiac output increased more for dynamic than for static exercise and for each mode more for KE than HG (P less than 0.001). Systemic resistance was lower for dynamic than static exercise and fell from resting levels by approximately 1/3 during DKE. The magnitude of the pressor response was related to the active muscle mass but independent of the contraction mode. However, the mode of contraction affected the circulatory changes contributing to the pressor response. Equalization of the pressor responses was achieved by proportionately larger increases in cardiac output during dynamic exercise.
Summaryobjectives To quantify expressed stigma in clients of the Kangemi program for HIV+ children, and to characterize the association between stigma and other population characteristics.methods By means of a household survey we created a stigma index and indices for other social and knowledge domains that influence HIV-related healthcare. We used v 2 , anova, and correlation to identify associations between domains.results The mean (±SD) expressed stigma on a six points scale (6 ¼ least stigma) was 3.65 ± 1.64. Composite scores on knowledge about AIDS were skewed toward more knowledge; and analysis of individual knowledge items indicates that most respondents reject erroneous traditional beliefs and myths about the causes and transmission routes of AIDS. Respondents who were younger, had never married, and had less education expressed greater stigma. Differences in stigma were associated with poor knowledge about AIDS and negative attitudes toward testing, but not with gender or tribal affiliation. Condom use at last intercourse, unrelated to stigma, was only 40% (n ¼ 218).conclusions While this population has good knowledge about AIDS and appraises risks realistically, it fails to reduce these risks. Associations between stigma and other domains can inform interventions that improve HIV care and mitigate spread of HIV.
At the end of 2001, AIDS-related deaths had left an estimated 900,000 living orphans in Kenya (UNAIDS/WHO Epidemiology fact sheet, Kenya report, 2004). Many of those orphans are also HIV+. In Eastern Kenya, the Lea Toto Kangemi Outreach Program provides support to families caring for HIV+ children, many of whom are orphaned or soon to be orphaned. A major challenge for these families is the stigma attached to the family. In 2003, the Kangemi Program conducted a household survey of client families. We examined markers of expressed stigma and the association between expressed stigma and other demographic and belief/knowledge domains. The focus of the present study was the specific belief/knowledge domain surrounding care/support of HIV+ persons. Our goal was to explore this domain in the Kangemi families and to examine its relationship to expressed stigma. We created an AIDS-related stigma scale from selected items in the household survey and cross-tabulated stigma scores with care/support knowledge items. We found significant associations between less expressed stigma and greater care/support knowledge. Our results have implications for interventions that reduce expressed stigma and/or improve quality of care.
1 Kinins, which are produced locally in arterial walls, stimulate the release of endothelium-derived vasodilator substances. Therefore, they may participate in the metabolic adaptation to chronic exercise that occurs in the coronary circulation. Experiments were designed to compare the reactivity to bradykinin in coronary arteries isolated from sedentary and exercised-trained dogs (for 8-10 weeks). 2 The organ chambers used in this study were designed for measurement of isometric tension and cell membrane potential with glass microelectrodes. Rings of canine isolated coronary arteries with endothelium were suspended in the organ chambers filled with modified Krebs-Ringer bicarbonate solution (37°C, gassed with 5% CO2 in 95 02), and were all treated with indomethacin to prevent interference from prostaglandins. 3 Bradykinin evoked concentration-dependent relaxations of the coronary arteries. However, the kinin was significantly less potent in relaxing coronary arteries from the sedentary dogs than those from the trained ones. 4 In the presence of N0-nitro-L-arginine (an inhibitor of nitric oxide synthases), concentrationrelaxation curves to bradykinin were shifted to the right in both types of preparations. Nonetheless, the peptide was still significantly more potent in arteries from exercise-trained animals. 5 In the electrophysiological experiments, concentration-hyperpolarization curves to bradykinin obtained in arteries from sedentary dogs were also significantly to the right of those in vessels from exercise-trained animals. Thus, in arteries from exercised animals, bradykinin more potently evoked the release of both nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF). 7 The angiotensin converting enzyme (ACE)-inhibitor, perindoprilat, shifted to the left the concentration-relaxation curves to bradykinin obtained under control conditions and in the presence of N0-nitro-L-arginine. The concentration-hyperpolarization curves to bradykinin were also shifted to the left by perindoprilat. The shift induced by the ACE-inhibitor in either type of preparation was not significantly different. 8 These findings demonstrate that exercise-training augments the sensitivity of the coronary artery of the dog to the endothelium-dependent effects of bradykinin. This sensitization to bradykinin may reflect an increased role of both NO and EDHF, and is not the consequence of differences in ACE activity in the receptor compartment.
We studied the effects of a-adrenergic receptor stimulation and calcium on automaticity of isolated canine Purkinje fibers during simulated ischemia and reperfusion. Ischemia included acidosis (pH 6.7), hypoxia (Po2=10-25 mm Hg), hyperkalemia (10 mM K'), and either normal or elevated [Ca2+], (2.7
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