The influence of acute and intermittent hypoxia on respiratory mechanics in the range of tidal volume of adult rabbits was studied. All is based on the assumption that the tissue structure of lung constitutes a conservative mechanical system and hence that pressure(P)-volume(V)hysteresis is primarily a result of surface tension(r)-surface area(s)hysteresis. It was found that the lung compliance of rabbits to acute hypoxia was decreased and respiratory work increased. Compared to control group (3.5?1.1mm),the working limbs of P-V loops of acute hypoxic rabbits increased by 49% (5.2?0.6mm). Such changes could be corrected in part by appropriate intermittent hypoxia, the length of working limbs of 5-day adaptation rabbits was 4.2?1.1(P

Suppression subtractive hybridization(SSH) is a good and highly effective method for gene cloning,which posses some character,such as convenient operation,high specificity,low background,good replication etc,and it can separate lower specific fragment.This article principally introduced its main technical points,strength and shortcomings and improvement of SSH,and also reviewed its applications in detecting the effects of radiation,heat,hypoxia,coldness and other environmental factors on gene expression.

In this paper,the structure,principle and application of combined chemical oxygenerator is described.Its character is that through the adjustable valve controlled by inspiration and expiration,it offers and halts oxygen supply.The utilization rate of oxygen is over 98%.The physico-chemical indices of the oxygen produced reach the national standard for medical oxygen.The experimental results in alti- tude field have shown that it can alleviate the syndroms of acute mountain sickness and reduce heart rate.