Browsing by Autor "Villena, M"

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Anthropometry and lung function of 10- to 12-year-old Bolivian boys
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1994) Villena, M
Abstract. Anthropometric measurements of 23 HAHSES, 44 HALSES, 43 LAHSES, and 28 LALSES boys (see Introduction to this Supplement) are presented here. They include body height (H), body weight (BW), upper arm circumference (UAC), and skinfold thickness taken at four locations. From these measurements, body fat, lean body mass, and body mass index (BMI = BW/H2) were calculated. The degree of maturation was assessed according to Tanner, orchidometry, and by quantification of testosterone in saliva. Lung function data include: vital capacity (VC), forced expired volume per 1 s (FEV1), functional residual capacity (FRC), residual volume (RV), and total lung capacity (TLC). The results show enhanced lung volumes in both HA groups in comparison to LA groups, with HALSES boys having the greatest increase, even though the LSES boys were significantly smaller compared to the HSES boys at both altitudes and their growth was delayed by approximately 2 years. From the anthropometric data it appears that physical growth of prepubertal boys is dependent on SES but not on high-altitude exposure. We tentatively conclude that chronic hypoxia per se does not affect physical growth in prepubertal boys in an Andean environment and that development of lung function is accelerated in relation to linear growth as has been suggested by other authors (15).
Cardiac and vascular disease prior to hatching in chick embryos incubated at high altitude.
(2010) Salinas, C E; Blanco, C E; Villena, M; Camm, E J; Tuckett, J D; Weerakkody, R A; Kane, A D; Shelley, A M; Wooding, F B P; Quy, M; Giussani, D A
The partial contributions of reductions in fetal nutrition and oxygenation to slow fetal growth and a developmental origin of cardiovascular disease remain unclear. By combining high altitude with the chick embryo model, we have previously isolated the direct effects of high-altitude hypoxia on growth. This study isolated the direct effects of high-altitude hypoxia on cardiovascular development. Fertilized eggs from sea-level or high-altitude hens were incubated at sea level or high altitude. Fertilized eggs from sea-level hens were also incubated at high altitude with oxygen supplementation. High altitude promoted embryonic growth restriction, cardiomegaly and aortic wall thickening, effects which could be prevented by incubating eggs from high-altitude hens at sea level or by incubating eggs from sea-level hens at high altitude with oxygen supplementation. Embryos from high-altitude hens showed reduced effects of altitude incubation on growth restriction but not on cardiovascular remodeling. The data show that: (1) high-altitude hypoxia promotes embryonic cardiac and vascular disease already evident prior to hatching and that this is associated with growth restriction; (2) the effects can be prevented by increased oxygenation; and (3) the effects are different in embryos from sea-level or high-altitude hens.
Desadaptación crónica a la vida en altura
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1997) Villena, M
A partir de la primera descripción hecha por Monge (1928), se sabe que en cierta época de la vida, un buen número de personas, hasta entonces normales, desarrollan una ERITROCITOSIS sin causa subsecuente. Las manifestaciones clínicas se manifiestan cuando el residente de grandes alturas, pierde su tolerancia a la hipoxia hipobárica. Eritrocitosis e hipoxia arterial en los habitantes de altura, son las dos principales características de esta afección, que evoluciona hacia el corazón pulmonar crónico. Se analiza la etiología del cuadro y, las diferencias entre Eritrocitosis excesiva (EE), Eritrocitosis Patológica de Altura (EPA) y Eritrocitosis Secundaria. Se presentan los resultados de estudios…
Efectos del consumo tradicional de hojas de coca sobre la respiración
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1997) Villena, M
La historia documentada sobre las hojas de coca se inicia en 1504 con una carta en la que Américo Vespucio describe sus primeros contactos con los utilizadores de hojas de coa, que había tenido ocasión de conocer en 1499 durante un viaje por las costas de la actual Venezuela. Posteriores a este documento existen muchos otros escritos por los cronistas españoles de la conquista. A través de estos testimonios se sabe que para los Incas, la coca constituía el centro de sus actividades religiosas y sus ritos. En la mayoría de estos documentos históricos, la coca era considerada como una planta inútil, perniciosa y demoniaca que impedía la difusión del cristianismo; sin embargo, algunos escritos hacían referencia a sus cualidades, señalando entre sus virtudes –transmitidas por la creencia popular- el uso con fines medicinales y antifatigantes. Entre las crónicas de la conquista, se encuentra la del religioso jesuita José de Acosta quién describió con precisión los síntomas del “Mal de Montaña” o “Mal de altura”, al relatar sus experiencias acompañando a las tropas españolas durante una travesía por los andes. En su obra “Historia Natural y Moral de las Indias” (1590) se encuentra una descripción detalladas de las molestias que sufren los recién llegados a la altura, que Acosta atribuyó a “la textura del aire delicado y sutil, que no está adaptado a la respiración del hombre…”. Ya en esa época, también se mencionaba el efecto benéfico de la utilización de hojas de coca para contrarrestar este mal (Garcilazo de la Vega, 1609).
Encuesta hematológica en dos alturas diferentes del altiplano boliviano
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1997) Villena, M
Anteriores estudios para determinar la prevalencia de Eritrocitosis Patológica de Altura en nuestro medio, utilizan valores promedio de serie roja en la altura, muy variables. Las razones de esta variabilidad pueden ser diversas y entre ellas, al parecer la más frecuente, esta referida a los criterios de selección de las muestras poblacionales estudiadas y consideradas como normales. La finalidad de nuestro estudio fue determinar el hematocrito (Ht) promedio en sujetos nativos, habitantes de grandes alturas previo examen médico básico y criterios de selección estrictamente cumplidos, y determinar la presencia de eritrocitosis excesiva en nuestro medio. Se presentan los resultados de una en cuesta hematológica efectuada en dos etapas: la primera efectuada en nativos de ambos sexos (n= 685), habitantes a 4085 m. y, la segunda efectuada en 1756 deportistas ocasionales de ambos sexos, habitantes a 3600 m (La Paz) y 4085 m. (El Alto). Lod datos …
Étude en double insu de l'effect de l'almitrine sur les malades porteurs de polyglobulie pathologique d'altitude
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1985) Villena, M
ABSTRACT. Chronic polycythaemia in people living at high altitude is associated with hypoxaemia due to a marked reduction in hypoxic and hypercapnie drives. The effect of almitrine, a chemoreceptor stimulant, was evaluated in 40 patients, with haematocrit values over 57 %, living in La Paz (3,600-4,000 m). Two studies were carried out. The aim of the first was to assess the ventilatory response, and the increase in Pao₂, due to almitrine in a double blind, placebo controlled protocol including 40 patients (mean haematocrit 66.8%). Almitrine was given orally at a dose of 3 mg. kg-1. Variance analysis showed that three hours later there was a significant increase in Pao₂, (+ 0.46 kPa), pH and respiratory frequency, with a significant reduction in Paco₂, (-- 0.4 kPa). The increase in ventilation (+ 17 %) was not significant. The aim of the second study was to assess the effect of almitrine on the polycythaemia. It was given orally at a dose of 1.5 mg• kg-1. day-1 to twelve patients over a four week period. Blood gases, ventilation (VE), oxygen consumption (VO₂), carbon dioxide production (VCO₂) and haematocrit were measured every week. There was a slight but significant reduction in haematocrit (-- 3.5 %). Pao₂, and all the other measured parameters (VE, Paco₂, pH, VO₂ Vco₂,) remained constant. The reduction in haematocrit was not therefore due to an increase in diurnal Pao₂, but is perhaps due to the improvement in pulmonary ventilation during sleep.
Functional respiratory exploration in pneumoconiosis
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 1996) Villena, M
We present the results of functional respiratory exploration in two series of patients with silicosis arising from ten mines situated at high altitude. The objective of this study is to show the importance of a complete functional respiratory evaluation in silicosis for the assessment of labor-related injury. We studied 91 patients (series A: n=74, series B: n=17). In addition to clinical-radiological exams, other measurements were taken: pulmonary volume and capacities (spirometer), pulmonary …
High altitude hypoxia and blood pressure dysregulation in adult chickens.
(2013) Herrera, E A; Salinas, C E; Blanco, C E; Villena, M; Giussani, D A
Although it is accepted that impaired placental perfusion in complicated pregnancy can slow fetal growth and programme an increased risk of cardiovascular dysfunction at adulthood, the relative contribution of reductions in fetal nutrition and in fetal oxygenation as the triggering stimulus remains unclear. By combining high altitude (HA) with the chick embryo model, we have previously isolated the direct effects of HA hypoxia on embryonic growth and cardiovascular development before hatching. This study isolated the effects of developmental hypoxia on cardiovascular function measured in vivo in conscious adult male and female chickens. Chick embryos were incubated, hatched and raised at sea level (SL, nine males and nine females) or incubated, hatched and raised at HA (seven males and seven females). At 6 months of age, vascular catheters were inserted under general anaesthesia. Five days later, basal blood gas status, basal cardiovascular function and cardiac baroreflex responses were investigated. HA chickens had significantly lower basal arterial PO2 and haemoglobin saturation, and significantly higher haematocrit than SL chickens, independent of the sex of the animal. HA chickens had significantly lower arterial blood pressure than SL chickens, independent of the sex of the animal. Although the gain of the arterial baroreflex was decreased in HA relative to SL male chickens, it was increased in HA relative to SL female chickens. We show that development at HA lowers basal arterial blood pressure and alters baroreflex sensitivity in a sex-dependent manner at adulthood.
The highs and lows of programmed cardiovascular disease by developmental hypoxia: studies in the chicken embryo.
(2018) Itani, N; Salinas, C E; Villena, M; Skeffington, K L; Beck, C; Villamor, E; Blanco, C E; Giussani, D A
It is now established that adverse conditions during pregnancy can trigger a fetal origin of cardiovascular dysfunction and/or increase the risk of heart disease in later life. Suboptimal environmental conditions during early life that may promote the development of cardiovascular dysfunction in the offspring include alterations in fetal oxygenation and nutrition as well as fetal exposure to stress hormones, such as glucocorticoids. There has been growing interest in identifying the partial contributions of each of these stressors to programming of cardiovascular dysfunction. However, in humans and in many animal models this is difficult, as the challenges cannot be disentangled. By using the chicken embryo as an animal model, science has been able to circumvent a number of problems. In contrast to mammals, in the chicken embryo the effects on the developing cardiovascular system of changes in oxygenation, nutrition or stress hormones can be isolated and determined directly, independent of changes in the maternal or placental physiology. In this review, we summarise studies that have exploited the chicken embryo model to determine the effects on prenatal growth, cardiovascular development and pituitary-adrenal function of isolated chronic developmental hypoxia.