RESUMO
An acrylic head enclosure, permitting rapid exchanges of atmospheric gases, was developed for investigations of physiologic and performance responses of small nonhuman primates to graded hypoxic hypoxia and hypercapnia. The total system included a neck yoke plate which served both as a physical barrier to arm and hand movements in the head area and as a base on which to rest the head enclosure. The transparent, airtight, head enclosure permitted rapid exchanges of controlled gas mixtures and the execution of performance tasks in an apparently comfortable experimental environment.
Assuntos
Câmaras de Exposição Atmosférica/veterinária , Cabeça , Macaca mulatta/fisiologia , Macaca/fisiologia , Restrição Física/veterinária , Animais , Câmaras de Exposição Atmosférica/instrumentação , Gases , Haplorrinos , RespiraçãoRESUMO
A cranial implant was developed to facilitate mass spectrometric gasometry in cerebral tissue of conscious primates. It is permanently fixed to the skull and allows repeated introduction of a Teflon diffusion membrane into the cerebrum. The implant is simple to manufacture and mount. It has been tolerated well with repeated introduction of the catheter for more than 6 mo in 10 rhesus monkeys. The preparation avoids the complication and artifacts of an acute surgical preparation for investigation of cerebral pO2 and CO2.
Assuntos
Encéfalo/metabolismo , Macaca mulatta/metabolismo , Macaca/metabolismo , Espectrometria de Massas/instrumentação , Animais , Dióxido de Carbono/metabolismo , Cateterismo/instrumentação , Cateterismo/veterinária , Feminino , Haplorrinos , Masculino , Consumo de Oxigênio , Pressão ParcialRESUMO
The effects of air, water, and air plus water head cooling on thermoregulatory responses and human operator performance were studied in nonacclimatized, heat-exposed men. Forty chamber exposures (46 degrees C, 30 mm Hg water vapor pressure) were conducted under noncooled and the aforementioned subconditions of head cooling. Five subjects, exposed for 80 min, were monitored for mean skin and rectal temperatures, heart rate, sweat loss, and compensatory tracking performance. A modified Air Force helmet shell provided facial air ventilation (24 degrees C) at 8 cfm. Eight interconnected neoprene modules fastened beneath a helmet linear provided water cooling (20 degrees C at 0.9 l/min). Tracking performances was unchanged across conditions. Elevation of rectal temperature and heart rate, sweat loss, and Physiological Index of Strain were significantly reduced by each condition of head cooling. Air is as effective as water as a cooling agent. Air ventilation acts synergistically with water cooling in reducing physiological strain. Relative merits of each approach to head cooling, in an operational context, are discussed.