Reduced incidence and severity of acute mountain sickness in Qinghai-Tibet railroad construction workers after repeated 7-month exposures despite 5-month low altitude periods.

The construction of the Qinghai-Tibet railroad provided a unique opportunity to study the relation between intermittent altitude exposure and acute mountain sickness (AMS). For 5 yr, workers spent 7-month periods at altitude interspaced with 5-month periods at sea level; the incidence, severity, and risk factors of AMS were prospectively investigated. Six hundred lowlanders commuted for 5 yr between near sea level and approximately 4500 m and were compared to 600 other lowland workers, recruited each year upon their first ascent to high altitude as newcomers, and to 200 Tibetan workers native to approximately 4500 m. AMS was assessed with the Lake Louise Scoring System. The incidence and severity of AMS in commuters were lower upon each subsequent exposure, whereas they remained similar in newcomers each year. AMS susceptibility was thus lowered by repeated exposure to altitude. Repeated exposure increased resting Sao(2) and decreased resting heart rate. Tibetans had no AMS, higher Sao(2), and lower heart rates. In conclusion, repetitive 7-month exposures increasingly protect lowlanders against AMS, even when interspaced with 5-month periods spent at low altitude, but do not allow attaining the level of adaptation of altitude natives.

Identification of Swertia mussotii and its adulterant Swertia species by 5S rRNA gene spacer.

OBJECTIVE: This research focused on analyzing the differences of 5S rRNA gene spacer sequences on Swertia mussotii and its commonly used adulterants, including S. franchetiana, S. wolfangiana and S. chirayita. METHOD: DNA was extracted from the collected Swertia samples. 5S rRNA intergenic spacers were amplified by PCR, sequenced and analyzed. RESULT: 5S rRNA gene spacer sequences were different between S. mussotii and its other three adulterants. Sequence divergence among species ranged from 30.6% to 65.0%. CONCLUSION: 5S rRNA spacers may be used as molecular authentication markers to differentiate S. mussotii and other commonly used Swertia adulterants. This result provides reliable and simple reference for the authentication of Swertia genus species.

Authentication of Saussurea lappa, an endangered medicinal material, by ITS DNA and 5S rRNA sequencing.

Wild SAUSSUREA LAPPA in the family Asteraceae is a highly endangered plant. On the other hand, the dried root of cultivated S. LAPPA (Radix Aucklandia, Muxiang) is a popular medicinal material for treating various gastrointestinal diseases. In the market, several medicinal plants including VLADIMIRIA BERARDIOIDEA, V. SOULIEI, V. SOULIEI var. MIRABILIS, INULA HELENIUM and I. RACEMOSA in the family Asteraceae and ARISTOLOCHIA DEBILIS in the family Aristolochiaceae have the trade name of Muxiang. To manage the concerned medicinal material, we investigated if the ITS and 5S rRNA intergenic spacers are effective for discriminating S. LAPPA from its substitutes and adulterants. Sequencing results showed that the similarities of ITS-1, ITS-2 and 5S rRNA intergenic spacers among S. LAPPA and related species were 56.3 - 97.8 %, 58.5 - 97.0 %, and 26.4 - 77.9 %, respectively. The intraspecific variation was much lower. There are also several unique changes in the S. LAPPA sequences that may be used as differentiation markers.

[The microscopical and HPLC identification of several" Muxiang" raw materials].

OBJECTIVE: To differentiate and identify several species of "Muxiang". METHODS: The main microscopic features and HPLC chromatograms of diagnostic components were studied. RESULTS: Distinguishable characters were found in two methods. CONCLUSION: The results provide reliable and simple reference for the authentication of raw materials of" Muxiang" species, especially the toxic species.

Who should not go high: chronic disease and work at altitude during construction of the Qinghai-Tibet railroad.

From 2001 to 2005, a new railroad linking Beijing with Lhasa was built by more than 100,000 workers, of whom 80% traveled from their lowland habitat to altitudes up to 5000 m to work on the railroad. We report on the medical conditions of 14,050 of these altitude workers, specifically with regard to preexisting illness. All subjects were seen at low and high altitude. Average age was 29.5 +/- 7.4 (SD) yr, range 20 to 62 yr; 98.8% of the subjects were men and 1.2% were women. Overall incidence of AMS upon first-time exposure was 51%, that of HACE 0.28%, and that of HAPE 0.49%. About 1% of the subjects were hypertensive before altitude exposure. Those with blood pressure >or=160/95 were excluded from employment at altitude. Altitude exposure led to a greater increase of blood pressure in hypertensives compared to normotensives. On prealtitude screening prevalence of cardiac arrhythmias was 0.33%. Since the majority of these were rather benign and occurring in young and otherwise healthy subjects, we allowed altitude employment. Follow-up at altitude was uneventful. Subjects with coronary heart disease and diabetes were excluded from altitude employment. Obesity was a risk factor for acute mountain sickness and for reduced work performance at altitude. Overweight subjects lost more weight during their altitude stay than subjects with normal weight. Altitude exposure was a risk factor for upper gastrointestinal tract bleeding, especially in combination with alcohol, aspirin, and dexamethasone intake. Asthmatic subjects generally did better at altitude compared to low altitude, with the exception of one subject who experienced an asthma episode from pollen exposure. In conclusion, careful evaluation of preexisting chronic illness and risk factors allowed prevention of altitude deterioration of a preexisting health condition, all the while allowing subjects with some specific conditions to work and live at altitude without problems.

[The vasoactive material and pulmonary vascular structural remodeling in rats].

AIM: To investigate the role of vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) on pulmonary vascular structural remodeling in rats and pika. METHODS: The Wistar rats which reside at 2 260 m were carried to 3 417 m. After they were fed 24 hours,2 weeks and 3 weeks respectively, the level of VEGF and ET-1 were measured using a kit by ELISA method. Pulmonary tissue was taken out to stain with elastica-Van Gieson. The amount of pulmonary arteries (< 100 microm) and the component ratio of MA, PMA,and NMA were calculated by using a light microscope. The ratio of right ventricle weight to left ventricle plus septum weight (RV/LV + S) were measured. RESULTS: The ET-1 was significantly different in pika as compared with 24 h, 2 weeks, 3 weeks hypoxic rats (P < 0.01) respectively. The levels of VEGF in 2 weeks, 3 weeks rats were much higher than that of pika but no difference was found between pika and 24 h hypoxic rats. The ratio of MA, PMA obviously increased, and NMA decreased significantly, right ventricular hypertrophy was developed in differ groups of hypoxic rats. CONCLUSION: The VEGF and ET-1 participate the muscularization of pulmonary vessels during hypoxia and play an important role in the process of hypoxic pulmonary hypertension in rats, however the VEGF and ET-1 may be maintainable only normal organic function in pika.