Effects of simulated 100 m Trimix conventional diving on oxidative stress and inflammatory reaction in rabbits / 中国应用生理学杂志

OBJECTIVE@#To investigate the effects of simulated 100 m Trimix conventional diving on tissue inflammatory cytokines in rabbits.@*METHODS@#Eight New Zealand rabbits were performed a simulated 100 m Trimix conventional diving program which was established according to the Haldane theory. The expression levels of interferon-gamma(IFN-), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), myeloperoxidase(MPO) and matrix metallo proteinase-9 (MMP-9) in rabbits lung and brain tissues were detected by Elisa after diving decompression. The tissue wet/dry ratio was calculated. The serum levels of superoxide dismutase (SOD),glutathione(GSH), catalase(CAT), malondiadehyde(MDA) and lipid peroxide(LPO) were detected by Elisa method in rabbits before and after diving.@*RESULTS@#The expressions of IFN-, TNF-α, IL-6, IL-8, MPO and MMP-9 in simulated diving group rabbits were significantly increased compared with the intact group(<0.05, <0.01); the simulated diving rabbits tissues wet/dry ratio had no significant changes compared with the intact group. After diving, the activities of SOD and GSH were decreased significantly (<0.01), while the contents of CAT, MDA and LPO were increased significantly (<0.01).@*CONCLUSIONS@#The simulated 100 m Trimix conventional diving had significant impact on oxidative stress and inflammatory reaction in rabbits, the results of wet/dry ratio showed that the diving rabbits had no tissue edema after decompression.

Investigation on Drug Resistance Threshold of Newly Found HIV Infected Persons in Shaanxi / 现代检验医学杂志

Objective To analyze the resistance gene sequences of newly untreated HIV infected people,and to understand the prevalence and epidemic characteristics of HIV drug-resistant strains in Shaanxi Province.Methods According to the rec-ommended by the World Health Organization HIV drug resisitance threshold(HIVDR-TS),sera from 47 newly diagnosed HIV infected patients aged 16~25 years were analyzed.In-house determination of pol gene partial sequence,using online CPR software to determine whether there was transmission of resistant mutants,and submitted to Stanford University in the United States online HIV drug resistance database for the extent of the drug resistance analysis,the phylogenetic tree was constructed using mega 5.0 software,analysis of subtypes.Results No spread drug mutations were found in 47 samples,but there were 14 samples that were found to have associated with resistance gene mutation sites,including the RT region T69N and E138A,V179D/E mutations,PR A71T/V,L10I/V mutation sites and in subtype CRF01_B a like this in the site K103R,with V179E and there was a synergistic effect,resulting in accordance with efavirenz(EFV)and nevirapine(NVP) drugs such as moderately resistant.The mutations found in the remaining 13 samples would lead to a low degree of resist-ance to some of the drugs,and there was no clinical significance.Conclusion The prevalence rate of HIV resistant strains in Shaanxi province was <5%,which be longed to the low epidemic level.It is not necessary to detect drug resistance before individual treatment,and it is necessary to carry out the investigation of drug resistance.

Calculation of underwater decompression schedule for the simulated 100 m Trimix conventional diving and verification of the schedule with animal experiment / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the underwater decompression schedule for 100 m Trimix conventional diving operations and evaluate its safety through a simulated rabbits Trimix conventional diving.</p><p><b>METHODS</b>According to the Haldane theory, the assumed time units, the classification of tissue compartments, the nitrogen super-saturation safety coefficient and the selection of methods used for the calculation of the simulated 100 m Trimix conventional diving schedule were properly selected, and the calculating method for the dive decompression schedule was thus firmly established. In our experiments, five tissue compartments were selected during the calculation of decompression schedule: 5 min, 10 min, 20 min, 40 min and 75 min, and the nitrogen super-saturation safety coefficient was calculated by 1.6. Eight New Zealand rabbits were performed a simulated 100 m Trimix dive program which was established according to the Haldane theory, and eight rabbits for intact group. The tissues wet/dry ratio and ethology were detected and observed before and after the simulated diving to evaluate the safety of decompression schedule.</p><p><b>RESULTS</b>By using the developed underwater decompression schedule, abnormal ethology changes in rabbits could not be observed after compression and decompression to the surface; and the tissues wet/dry ratio of simulated diving rabbits had no significant changes compared with the intact group (P > 0.05).</p><p><b>CONCLUSION</b>The decompression schedule calculated by Haldane theory seemed to be safe and reliable, the diving breathing gas concentration did not cause oxygen toxicity and nitrogen narcosis among the dive rabbits, and dive efficiency was greatly improved by using enriched oxygen gas in UPTD safety range during decompression.</p>

Simulated high altitude diving experiment for the underwater construction operation.

The simulated dive experiments were conducted at the high altitude of 4500 meters and 5000 meters, for the requirement of diving operation in the lakes at the altitude of 4442 meters for the construction of large-scale hydroelectric power station. The high & low pressure chamber-complex was used, and 15 professional divers participated in the experiment. The divers were stayed at the altitude of 4500 and 5000 meters for 7-9 days. Totally 85 persons-times of dives to the depths of 30-50 meters were operated; they stayed under the water for 30-90 minutes while processing physical activities. During the experiment, we studied the pressurization procedure, decompression table, and physiological functions of the divers. The results indicate that, although the relative pressure differences between the surface and underwater was larger at high altitude than at sea level, the appropriate prolongation of the compression time was able to prevent the difficulty in pressure regulation for the divers to avoid the injury of middle ear. Four tables of the decompression A, B, C and D was calculated with Haldane's theory, and the speed of decompression increased in the order from A to D. The safest procedure was C, and there was no decompression sickness and bubbles in body of the divers. The methods of decompression included underwater stage decompression, surface decompression, oxygen-breathing decompression, and repetitive diving decompression. The surface decompression was the most suitable method for the high altitude, as it could greatly decrease the time in the cold water for the divers. The power spectrum analysis of EEG (electroencephalogram) indicated that, when the divers were exposed to the altitude of 5000 meters, the delta activity in EEG increased, alpha and beta activity decreased. And the delta activity decreased, the alpha and beta activity increased while diving during a dry condition. According to the diving and decompression procedure studied under simulated conditions, 272 person-times of diving training and underwater operations were processed in a high altitude hydroelectric power station at the altitude of 4442 meters, including photographing, video-recording, measuring, and drilling. There were no signs and symptoms of decompression sickness and bubbles.