Listar IBBA - Instituto Boliviano de Biología de la Altura por autor "Vitzthum, Virginia J"
Mostrando ítems 1-11 de 11
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A prospective study of early pregnancy loss in humans
Vitzthum, Virginia J; Spielvogel, Hilde; Thornburg, Jonathan; Brady West, MA (Fertility and Sterility, 2006-08)Objective: To test two hypotheses: In spontaneous conceptions, early pregnancy loss (EPL) is associated with [1] inadequate luteal (ovarian) P, and/or [2] elevated follicular (adrenal) P. Design: A population-based ... -
Assessing salivary progesterone in coca-leaf chewing populations
Vitzthum, Virginia J; Von Dornum, Miranda; Ellison, Peter T; Sandy, Irene (Population Studies Center, University of Michigan, 1990-05)ABSTRACT. Although there is evidence for reduced fertility in Andean and Himalayan populations at higher altitudes, factors other than hypoxia may be primarily responsible. A potentially valuable approach in the ... -
Does Hypoxia impair ovarian function in Bolivian women indigenous to high altitude?
Vitzthum, Virginia J; Ellison, PT; Sukalich, S; Cáceres, E; Spielvogel, Hilde (HIGH ALTITUDE MEDICINE & BIOLOGY, 2000)Abstract. Fertility appears to be reduced in at least some high altitude populations relative to their counterparts at lower elevations. Inferring from the difficulties with reproduction of newcomers to high altitude and ... -
Effect of menstrual cycle phase on exercise performance of high-altitude native women at 3600 m
Brutsaert, Tom D; Spielvogel, Hilde; Cáceres, Esperanza; Araoz, Mauricio; Chatterton, Robert T; Vitzthum, Virginia J (The Journal of Experimental Biology, 2002)Summary. At sea level normally menstruating women show increased ventilation (VE) and hemodynamic changes due to increased progesterone (P) and estrogen (E2) levels during the mid-luteal (L) compared to the mid-follicular (F) ... -
Epidemiological transitions, reproductive health, and the Flexible Response Model
Vitzthum, Virginia J; Spielvogel, Hilde (ECONOMICS AND HUMAN BIOLOGY, 2003)Abstract. In concert with improving standards of living since the mid-19th century, chronic and non-infectious diseases replaced infectious diseases as the major causes of mortality in more developed countries. Thus, ... -
Factors influencing the use of biomedical health care by rural Bolivian anemic women : structural barriers, reproductive status, gender roles, and concepts of anemia
Bedwell, Rebecca M; Spielvogel, Hilde; Bellido, Diva; Vitzthum, Virginia J (PLOS One, 2017-01-26)Abstract. The persistently high prevalence of anemia in rural highland Bolivia argues for targeted iron supplementation. We evaluated the cultural, structural and behavioral factors that may facilitate or impede an anemic ... -
Interpopulational differences in progesterone levels during conception and implantation in humans
Vitzthum, Virginia J; Spielvogel, Hilde; Thornburg, Jonathan (PNAS, 2004-02-10)Clinical studies of women from the United States demonstrate a sensitivity of the ovarian system to energetic stress. Even moder ate exercise or caloric restriction can lead to lower progesterone levels and failure to ... -
New data demonstrates that relationship of salivary to serum progesterone in Bolivian women is comparable to that in other populations
Thornburg, Jonathan; Bellido, Diva; Stewart, Rose; Spielvogel, Hilde; Echalar, Lourdes; Burch, Jennifer; Vitzthum, Virginia J (36th Annual Meeting Minnesota, 2011-04-13)Abstract. Salivary progesterone (P) concentration is widely used in field studies as a relatively easy-to-measure proxy for serum P. Chatterton et al. [Fertility & Sterility 86:723 (2006)] compared sample means of ... -
Salivary progesterone levels and rate of ovulation are significantly lower in poorer than in better-of urban-dwelling Bolivian women
Vitzthum, Virginia J; Bentley, Gillian R; Spielvogel, Hilde; Cáceres, Esperanza; Thornburg, Jonathan; Jones, Lary; Shore, Sarah; Hodges, Kelly R; Chatterton, Robert T (Human Reproduction, 2002)Agriculturalists in less-developed countries (LDC) have lower progesterone levels than urban industrialized populations. However, it is unknown if urban LDC populations are also relatively lower. We tested whether urban ... -
Seasonal and circadian variation in salivary testosterone in rural Bolivian men
Vitzthum, Virginia J; Worthman, Carol M; Beall, Cynthia M; Thornburg, Jonathan; Vargas, Enrique; Villena, Mercedes; Soria Sánchez, Rudy; Cáceres, Esperanza; Spielvogel, Hilde (American Journal of Human Biology, 2009-02-19)Abstract. Testosterone (T) plays a key role in the increase and maintenance of muscle mass and bone density in adult men. Life history theory predicts that environmental stress may prompt a reallocation of such investments ... -
Seasonal modulation of reproductive effort during early pregnancy in humans
Vitzthum, Virginia J; Thornburg, Jonathan; Spielvogel, Hilde (American Journal of Human Biology, 2009-03-03)Abstract. Life history theory predicts that early pregnancy presents a relatively low cost, uncontested opportunity for a woman to terminate investment in a current reproductive opportunity if a conceptus is of poor quality ...