Rambaut P C, Leach C S, Whedon G D
Medical Sciences Division, NASA-Johnson Space Center, Houston, TX 77058, USA.
Acta Astronaut. 1979 Oct;6(10):1313-22. doi: 10.1016/0094-5765(79)90123-1.
A metabolic balance study was conducted on the three crewmembers of the 84-day Skylab IV earth orbital mission. Dietary intake was controlled, monitored, and kept very nearly constant for a period commencing 21 days prior to flight, throughout flight, and for a period of 18 days postflight. Within the first 30 days of flight urine calcium rose to a level approx. 100% above preflight levels and remained elevated for the remainder of the flight. Fecal calcium excretion increased more slowly but continued to accelerate throughout the flight and did not return to baseline levels during the postflight period. Urinary nitrogen increased to 25-30% above preflight levels within one month following launch and thereafter gradually subsided toward control values. The overall losses of calcium averaged approx. 200 mg per day throughout the mission while nitrogen losses averaged 590 mg. Various other indices of musculoskeletal deterioration are discussed and correlated. The parallelism between the effects of weightlessness and bed rest is reviewed. It is noted, that no evidence is yet available as to the identity of the initial biological response to the absence of gravity.
对执行84天天空实验室4号地球轨道任务的三名机组人员进行了代谢平衡研究。从飞行前21天开始，在整个飞行期间以及飞行后18天内，对饮食摄入进行控制、监测并使其保持几乎恒定。在飞行的前30天内，尿钙升至比飞行前水平高出约100%的水平，并在飞行剩余时间内一直保持升高。粪便钙排泄增加较慢，但在整个飞行过程中持续加速，在飞行后期间未恢复到基线水平。发射后一个月内，尿氮增加到比飞行前水平高出25 - 30%，此后逐渐降至对照值。在整个任务期间，钙的总体损失平均约为每天200毫克，而氮损失平均为590毫克。讨论并关联了肌肉骨骼退化的各种其他指标。回顾了失重和卧床休息影响之间的相似性。需要注意的是，关于对失重最初生物学反应的本质，目前尚无证据。
