Hypoxia is a significant problem of high altitude aviation. Acute hypoxia has been recognized as a critical physiological threat. In addition, physiological changes for adaptation to chronic hypoxia, such as angiogenesis and development of fibrosis, have been shown in many studies. Pathological fibrosis of the skin, lungs, liver and other organs are characterized by excessive synthesis and accumulation of collagen and other extracellular matrix. Transforming Growth Factor-β(TGF-β) stimulates collagen synthesis and accumulation, and is implicated in the development of pathological fibrosis of organs. This study investigated the effect of hypoxia on the expression of Type I procollagen(COL1A1)and TGF-βmRNA in NIH3T3 fibroblasts. NIH3T3 fibroblasts were cultured under normal (21% oxygen) and hypoxic (1% oxygen) condition for 24 hours. The expression of COL1A1 and TGF-mRNA was examined using reverse transcriptase-polymerase chain reaction (RT-PCR) and densitometric analysis by the National Institutes of Health Image analysis program. Hypoxia induced 3.48 and 2.46 fold increase in COL1A1 and TGF-β mRNA, respectively. These results suggest that hypoxia may be up-regulates collagen production in fibroblasts, and TGF-β may play an important role in development of fibrosis in hypoxia.

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Urinary catecholamine responses of fighter pilots were investigated in Aerial Combat Maneuver (ACM). The levels of urinary adrenaline (Ad) and noradrenaline (NA) were determined in fighter pilots during ACM with three types of aircraft (F-4, F-15 and F-2). The levels of Ad for post-flight were significantly higher than for pre-flight, while changes were not significant for NA. The ratios (post-/pre-flight) of Ad in ACM with different types of aircraft are relatively similar values. Our results indicate that the ratio of urinary Ad as a good indicator to stress adaptation during ACM in fighter pilots.

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Fighter pilots are exposed to high sustained Gz force during air-to-air combat maneuvering. Muscle activities are very important because of its main role in pilot toleration of high Gz forces. The purpose of this study was to evaluate the differences of several muscle activities during anti-G straining maneuver (AGSM) and measure electromyographic(EMG) activities of experienced pilots during acceleration training ［GOR (Gradual Onset Rate) and ROR (Rapid Onset Rate) profiles］. Subjects are thirty six experienced pilots. Their mean age (±SD)was 25.4±2.3yr, mean height was 173.3±6.3cm, and mean weight was 69.7±9.9kg. They were exposed to two training profiles (GOR and ROR), with Gz level from 4.0Gz to 7.0Gz and onset rate from 0.26 to 0.55Gz/sec. (GOR, range of sustained time were 15sec. to 30sec.) and onset rate of 2.0Gz/sec. (ROR, range of sustained time were 5sec. to 20sec.). During the training, G suit was fitted and AGSM was performed . In this study, EMG was measured from m. vastus lateralis (VL), m. rectus abdominis (RA), m. sternocleidomastoideus (SCM) and m. elector spinae (ES) of each subject. The mean and peak muscular strain for each muscle was calculated as the percentage of maximal voluntary contraction (%MVC). The EMG were measured using a portable four channel EMG device (ME3000P, Mega Electronics Ltd., Kuopio, Finland). Before Gz exposure, the maximal voluntary contraction (MVC) of each muscle was measured.

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Polycyclic aromatic hydrocarbons (PAHs), several of which have both mutagenic and carcinogenic properties, are present in aircraft exhaust. In the present study, a reversed-phase high performance liquid chromatography (HPLC) with fluorescence detection was developed for the determination of 15 PAHs. A SUPELCOSIL LC-PAH column was used with a gradient of acetonitrile/water as the mobile phase, together with five excitation and emission wavelength pairs. The wavelength pairs were 284/350 nm for the 2- and 3-ring PAHs, 270/375 nm for 3- and 4-ring PAHs, 290/405 nm for 4-, 5- and 6-ring PAHs, 262/300 nm for fluorine, and 252/474 nm for anthracene, fluoranthene, benzo(b)fluoranthene, indeno(1,2,3-cd)pyrene. The calibration curves of the 2- and 3-ring PAHs and pyrene were linear (R2>0.999) from 0.0625 to 6.25μg/mL, anthracene and fluoranthene were linear (R2>0.99) from 0.0625 to 6.25 μg/mL, benzo(b)fluoranthene was linear (R2>0.99) from 0.0125 to 0.625 μg/mL, indeno(1,2,3-cd)pyrene was linear (R2>0.99) from 0.0625 to 0.625 μg/mL, those of other PAHs were also linear (R2>0.999) from 0.00625 to 0.625 μg/mL. The limits of detection of 15 PAHs were ranged from 7.4 ng/mL to 530 ng/mL. Separation of all PAHs was completed within 5 min. These results indicate that our HPLC with fluorescence method is rapid and sensitive for simultaneously determining PAHs.

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