performed the same training program for the experimental span of four weeks. Results:
Hemoglobin and hematocrit did not obviously rise, erythropoietin, maximal oxygen uptake and
performance in 3000m race had tendency towards elevation in hypoxic group, which were higher
than control group, but not different (P0.05) compared to intermittent hypoxic training. VEGF in
initial phase in hypoxic group obviously increased compared to later phrase of intermittent
hypoxic training, from 32.8±6.8pg/ml to 43.2±13.5pg/ml(P<0.05 ), and higher than those of
control group. The high level of VEGF in hypoxic group went on two weeks after intermittent
hypoxic training. Conclusion: Intermittent hypoxic training at simulated 4000m has a few effects
on mid-long distance runners native to the plateau. For obtaining more training effects, mid-long
distance runners should prolong time of living in hypobaric chamber, or perform workouts at
4000m every week
68.
TETRANDRINE RELAXES THE PULMONARY ARTERY IN RAT HYPOXIA . Yun Hai-
Xia
1
, Jing Guo-En
1
, Yang Ying-Zhong
1
, Ma Lan
1
, Bai Zhen-Zhong
1
, Ge Ri-Li
1
. Research Center
for High Altitude Medicine, Qinghai Medical College, Xining
1
.
Aim: It was reported that tetrandrine is a selective inhibitor of the calcium channel. It can
cause relaxation of smooth muscle cells of blood vassals, trachea and bladder. However the
effects of Tetrandrine on pulmonary artery in the rat has not been studied. Methods: The tissue
bath technique was used to record the tension of pulmonary artery. The dose-response curves for
the concentrations of KCl induced by tetrandrine were observed with isolated rat pulmonary
artery ring (PAR). Isolated PAR was precontracted with 10 mol/L phenylephine (PE) followed by
addition of different concentrations of tetrandrine. The effect on PAR by cumulative doses of
tetrandrine was observed after the presence of nitric oxide synthase inhibitor (L-NAME) and
soluble guanylate cyclase inhibitor (methylthioninium). Results: 1. The maximal responses of
KCL were reduced in the presence of tetrandrine. 2. Rat PAR showed dose- dependent relaxation
with increasing concentrations of tetrandrine after being precontracted with PE (10mol/L).
However, it these relaxation effects were not affected by the presence of L-NAME and
methylthioninium. Conclusion: Tetrandrine was effective in relaxation of rat pulmonary artery in
vitro in a dose-dependent fashion. The mechanism might be related to its blocking effect on
calcium channel but not the NO-cGMP pathway. The work was funded by Natural Sceince
Foundation of China (302600354).
69.
A STUDY OF HEART STRUCTURE IN 1062 HEALTHY CHILDREN LIVING AT
DIFFERENT ALTITUDES . Qi Hai-Ying
1
, Ma Ru-Yan
1
, Sun Kun
2
, Ge Ri-Li
3
. Dept. Cardiology,
Qinghai Provincial Women and Children Hospital; Xining; Qinghai, Dept. Cardiology, Shanghai
Children Medical Center, Shanghai, P.R. China
2
, Qinghai Research Center for High Altitude
Medicine, Xining, Qinghai, P.R. China
3
.
Although some studies have reported change of right heart structure in all high altitude
residents, this change has not been studied in healthy children living at different altitudes. The
aim of this present study was to obtain heart structure in healthy children living at different
altitudes. We compared heart structure in two groups of children: those living at high altitude vs.
those living at sea level, and Han children vs. Tibetan children. 1062 healthy children aged 0-14
yrs (residing at 16m, 2260m and 3700m) were recruited into this study. All children were divided
into seven age groups. We measured right ventricular outflow (RVOT), main pulmonary artery
(PA), aorta (AO), right ventricular diameter in diastolic period (RVDd), right atrium (RA),
thickness of right ventricular free wall (RVFW), interventricular septum (IVS), left ventricular
diameter in diastolic period (LVDd) and PA/AO using 2-D echocardiography. There was an
increasing trend in the RVOT, A and PA/AO of the three groups with the altitude (p< 0.05_0.01)
in each age group. There were no significant differences in RA, RVFW, RVDd, IVS and LVDd
between 2260m groups and 16m groups. Whereas RA, RVDd in 3700m groups were much larger
than those in 2260m and 16m groups (p<0.05), RVFW and IVS in 3700m groups were thicker
than those in 2260m and 16m groups, and LVDd in 3700m groups was smaller than that in
