FN group (p<0.01). The microcirculatory perfusions of both hind legs of FHAC group were
significantly lower than those of FN and FAH groups (p<0.01). The microcirculatory perfusions
of both hind legs decreased markedly in FN after cold injury. It suggests that the frostbite damage
can affect microcirculatory perfusion of another leg besides the region of frostbite. The fall of
microcirculatory perfusion before freezing in FAH group indicated that there was compensatory
blood redistribution during acute hypoxia. The changes of microcirculatory perfusion in FAH
group post-freezing indicated that acute hypoxia can aggravate the frostbite damage. The
microcirculatory perfusion of FHAC group pre-freezing was significant1y lower than those of FN
and FAH group (p<0.01) and after freezing the perfusion of frostbitten leg in FHAC group was
significant1y lower than that in FN group (p<0.01), suggesting that hypoxia acclimation may
cause disturbance of microcircu1ation and worsen the frostbite damage at high altitude.
175.
DISTINCT RESPONSES OF PULMONARY ARTERIAL ENDOTHELIAL CELLS AND
PULMONARY ARTERIAL SMOOTH MUSCLE CELLS TO HYPOXIA. Wang Pei-Yong
1
, Liu
Jian
1
, Zeng Qiang
2
, Xu Shu-Min
3
, Yu Zhong-He
3
, Sun Bing-Yong
3
. Department of
Pathophysiology, College of High Altitude Military Medicine, Third Military Medical Un
1
,
Institute of Geriatrics, The Great Wall Hospital, Beijing
1
008
532
, Department of Respiratory
Diseases, Beijing Military General Hospital, Beijing
3
.
The objective of the present study was to compare the mitogenic changes, secretion of
peptides between pulmonary arterial endothelial cells (PAECs) and smooth muscle cells
(PASMCs) under hypoxic conditions. PAECs and PASMCs from newborn calf were harvested
from the same small pulmonary arterial segment, and were cultured in RPMI-1640 medium with
20_ fetal bovine serum at 37 in 5% CO2 incubator. It was found that hypoxia inhibited
proliferation of PAECs significantly, stimulated Endothelin-1 (ET-1) mRNA expression and ET-
1 release, promoted angiotensin II (ATII) release, but reduced arterial natriuretic peptide (ANP)
release. Nitric oxide (NO) donor SIN-1 (0.1-1.0 mM) inhibited but endogenous NO inhibitor L-
nitro-arginine (LNA, 2.5 mM) promoted AT secretion from PAECs significantly under both
normoxic and hypoxic conditions. It was also found that the concentration of cyclic guanosine
monophosphate (cGMP) in PAEC decreased significantly at 24h under hypoxia. It is interesting
that the responses of PASMCs to hypoxia were just the opposite. Hypoxia stimulated
proliferation of PASMCs significantly, repressed ET-1 mRNA expression and ET-1 release, also
inhibited ATII release, but stimulated ANP release. Under normoxic condition, if SIN-1 added,
AT secretion from PASMCs decreased to the level of that in hypoxia, while under hypoxic
condition, if LNA added, AT secretion from PASMCs increased to the level of that in normoxia.
It was also found that the concentration of cGMP in PASMCs increased significantly for 24h
under hypoxia, which can be cancelled by addition of LNA. The results above indicated that the
responses of PAECs and PASMCs to hypoxia are distinct. Balance between paracrine from
PAECs (strengthened secretion of vasoconstrictor and reduced secretion of vasodilator) and
autocrine from PASMCs (just the opposite to those of PAECs) may determine the development
and extent of hypoxic pulmonary hypertension.
176.
SURVEY OF HYPERTENSION PREVALENCE OF MID-ELDERLY POPULATION IN THE
URBAN AND RURAL AREAS OF LHASA TIBET CHINA. ZaXi Ping-Cuo
1
, Huang Gui-
Wen
1
, Hu Xue-Jun
1
Autonomous Region, Lhasa 
51
.
To study the prevalence rate of hypertension and the risk factors of the mid-elderly
population in the urban and rural areas of Lhasa. Methods: A total of 4853 people aged over 40
were surveyed. Blood Pressure, Blood Glucose and BMI etc were examined. Result: The
prevalence rate of hypertension in the mid-elderly people was 40.68%, which has a positive
correlation with aging. The prevalence rate of ISH increased progressively with aging, especially
among over 60 years old. It was found that the prevalence rate of hyperlipidemia, overweight and
diabetes in hypertension were much higher than that in normotensives (P_0.05). Aware rate of
