Asunto(s)
Cuerpo Carotídeo/fisiología , Nervio Glosofaríngeo/fisiología , Concentración de Iones de Hidrógeno , Transporte Iónico , Transducción de Señal/fisiología , Amilorida/análogos & derivados , Amilorida/farmacología , Animales , Transporte Biológico Activo/efectos de los fármacos , Dióxido de Carbono/farmacología , Cuerpo Carotídeo/citología , Cuerpo Carotídeo/efectos de los fármacos , Proteínas Portadoras/efectos de los fármacos , Gatos , Hipoxia de la Célula/efectos de los fármacos , Líquido Intracelular/metabolismo , Transporte Iónico/efectos de los fármacos , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Nicotina/farmacología , Oxígeno/farmacología , Oxígeno/fisiología , Transducción de Señal/efectos de los fármacos , Sodio/metabolismo , Cianuro de Sodio/farmacología , Intercambiador de Sodio-Calcio , Intercambiadores de Sodio-Hidrógeno/antagonistas & inhibidoresRESUMEN
The paper presents new observations on young high altitude natives (Andes and Himalayas), testing the hypothesis that periodic breathing with apnea during sleep is determined by their ventilatory sensitivity to hypoxia and its interaction with the sleep state. The hypothesis is in general supported by the evidence. But, contrary to expectation, the ventilatory sensitivity to hypoxia in the Sherpa children was significantly lower than those in the Andes. Despite that departure, the magnitude of ventilatory periodicity among the subjects was internally consistent with their ventilatory sensitivity to hypoxia. Although the carotid chemosensory input is the pacesetter for the reflexive periodicity, mechanisms in the central nervous system can influence it significantly.
Asunto(s)
Altitud , Células Quimiorreceptoras/fisiología , Periodicidad , Respiración/fisiología , Síndromes de la Apnea del Sueño/fisiopatología , Sueño/fisiología , Adolescente , Adulto , Animales , Cuerpo Carotídeo/fisiología , Gatos , Niño , Chile/etnología , Humanos , Nepal/etnología , Respiración/inmunología , Síndromes de la Apnea del Sueño/etiologíaRESUMEN
"This paper proposes a simple method for evaluating death registration completeness during intercensal periods. It is easier to implement than alternative methods but its main advantage is making explicit the dependence of results on the quality of readily observed demographic variables. Applications are made to data from South Korea and Argentina."
Asunto(s)
Certificado de Defunción , Estudios de Evaluación como Asunto , Métodos , Proyectos de Investigación , Estadísticas Vitales , Américas , Argentina , Asia , Países en Desarrollo , Asia Oriental , Corea (Geográfico) , América Latina , Características de la Población , Investigación , América del SurRESUMEN
Arterial blood gases, acid-base and hematocrit of six highest inhabitants on Aucanquilcha (5950 m) in Chile were studied. These blood gases were compared with the alveolar gases of highest mountain climbers in Nepal, Sherpas and acclimatized lowlanders, and on average high altitude natives in the Chilean and Peruvian Andes and in the Nepal Himalayas. The mean arterial PCO2 (27.5 Torr) was lower than the standard sea level normal values, indicating a modest hypoxic hyperventilation. The mean arterial pH was 7.400, showing a complete renal compensation of respiratory alkalosis. The mean hematocrit (62%) and hemoglobin (20.7 g/dl) values were greater than the standard sea level values. These blood data showed that the highest inhabitants were acclimatized to hypoxia of their residential altitude. The respiratory gases showed less hyperventilation in the highest inhabitants and Sherpa mountaineers of high altitudes relative to the acclimatized lowlanders. Also, the average high altitude natives in the Andes and Himalayas showed less hyperventilation compared to the acclimatized lowlanders. We conclude that the attenuated hyperventilation is an appropriate respiratory adaptation to high altitude hypoxia in the native high altitude residents, allowing them to conserve metabolic energy expended for hyperventilation and to use the ventilatory reserve for a better performance at greater altitudes.
Asunto(s)
Altitud , Dióxido de Carbono/sangre , Oxígeno/sangre , Respiración , Adaptación Fisiológica , Adulto , Dióxido de Carbono/fisiología , Chile , Humanos , Masculino , Montañismo , Oxígeno/fisiología , Alveolos Pulmonares/análisisRESUMEN
To evaluate the role of genetic and environmental factors in the genesis of large lungs in high-altitude natives, we measured forced vital capacity (FVC), static lung pressure-volume characteristics and maximum expiratory flow-volume loops in 17- to 20-yr-old Peruvian natives to 3,850 m (highlanders) and 800 m (lowlanders). Forced vital capacity was 5.11 +/- 0.64 liters in highlanders, 116 +/- 11% of predicted; and 3.73 +/- 0.32 liters in lowlanders, 84 +/- 7% of predicted. Lung elastic recoil at functional residual capacity and at total lung capacity, and size-corrected pressure volume curves were similar in the two groups. Despite the larger volumes in highlanders, density-corrected maximum flow rates were similar in highlanders and lowlanders, and flow expressed in FVC'S-S-1 was less in highlanders. Upstream conductance at 50% FVC expressed in fvc's-s-1-cmH2O was 0.094 +/- 0.023 in highlanders vs. 0.147 +/- 0.050 in lowlanders. Flow rates did not change in sojourners to altitude, suggesting that the lower values of highlanders were due to anatomic factors. These findings suggest that airways, which form in fetal life, do not participate in adaptation to altitude, and that the large lungs of highlanders result from postnatal environmental hypoxic stimulation of lung growth. Our results illustrate the importance of "dysynaptic" lung growth in determining patterns of adult lung function.