group. EPO increased with increasing altitude. This could result from the hypoxia in high altitude
areas and may be one of the main causes of erythromatosis.
155.
IMMUNOGLOBULIN IN HAN CHINESE AND NATIVE TIBETAN CHILDREN AT HIGH
ALTITUDE. Li Ming
1
, Shen Yan-Jun
1
, Zhou Ling
1
. Dept. of Pediatric, Affiliated Hospital of
Qinghai Medical College, Xining, China
1
.
We hypothesized those native Tibetan children, whose ancestors have inhabited the
Himalayan Plateau for centuries, have superior immunity to disease at high altitude than Han
children whose ancestors moved to Tibet from lowland areas of China in 1951. We investigated
the levels of immunoglobulins in Han children compared to those of native Tibetan children. We
randomly selected 120 healthy children aged 6-8 years and divided them into four groups (30
Han, 30 Tibetan at 2260m and 30 Han, 30 Tibetan at 3700m). We measured serum
immunoglobulins (IgG, IgA, and IgM) of all subjects using immune turbidimetry using a
Japanese OLYMPUS auto-analyzer. We compared the levels of IgG, IgA and IgM between the
two altitudes and the two ethic groups. At 2260m there were no significant differences of IgG,
IgA and IgM between Han and Tibetan children (11.18±0.76 vs. 11.18±0.84, 1.36±0.07 vs.
1.36±0.07, 1.37±0.18 vs. 1.37±0.10 mmol/L respectively, mean ±SD, p0.05). At 3700m the levels
of IgA and IgM in Tibetan children greatly increased compared to those in Han children
(2.28±1.03 vs.1.71±0.43, 2.19±0.88 vs. 1.50±0.39 mmol/L; respectively, mean ±SD, p<0.01-
0.001). Among the Han children, there were no differences in the levels of IgG, IgA and IgM
between the 2260m and 3700m groups (p0.05). Among Tibetan children, the levels of IgA and
IgM in the 3700m group were much higher than those of the 2260m group (p<0.001). In
conclusion, at high altitude the native Tibetan children had significantly higher levels of IgA and
IgM compared to the Han children.
156.
STUDY ON THE ULTRASTRUCTURE OF PITUITARY ACTH CELLS AT DIFFERENT
ALTITUDE IN RATS. Zhao Ming
1
, Geng Pai-Li,
1
, Wu Hong-Fu
1
, Zhu Hai-Hong
1
, Zhang Xian-
Jun
1
, Wu Yue
1
, Zhao Jiu-Da
1
. Qinghai Medical College
1
.
To observe the changes of ultrastructure of ACTH cells in pituitary at different altitude and
discover the role of ACTH in the hypoxic stress and the relationship between hypoxia and the
endocrine function of pituitary ACTH cells in rat. Methods: Divided wistar rats into three groups
(1700m, 3100m, 4050m), and after moved them to high altitude areas for 12 days, observing the
changes of ultrastructure of rat's pituitary by using electron microscopy. Results: The amount and
scale of secretary granules and cellular apparatus of ACTH cells in rats showed some changes
among different groups. The secretary granules and cellular apparatus such as mitochondria and
tough endoplasmic reticulum of ACTH cells in 3100M group and 4050M group showed bigger
size and more numbers than that of the 1700M group's and the nucleolus of ACTH cells have
been shown corresponding changes. Conclusion: Hypoxia has some effects on the ultrastructure
of ACTH cells in rat's pituitary. It showed that, however, ACTH may be a key physiologic and
pathophysiologic factor for involving the stress reaction to hypoxia in high altitude.
157.
ACUTE HYPOXIA-INDUCED DECREASE IN AEROBIC PERFORMANCE IN
ENDURANCE ATHLETES. Pascal MOLLARD
1
, Xavier WOORONS
1
, Muriel LETOURNEL
2
,
Jérémy CORNOLO
1
, Christine LAMBERTO
3
, Jean-Paul RICHALET
1
. EA
23
6
3
, ARPE,
Université Paris
13
, Bobigny, France
1
, Hôpital Avicenne, AP-HP, Université Paris
13
, Bobigny,
France
2
, EA
23
6
3
, Hôpital Avicenne, AP-HP, Université Paris
13
, Bobigny, France
3
.
Purpose: We aimed to evaluate the importance of factors responsible for VO2max reduction
in trained subjects exposed to acute hypoxia. Methods: 17 healthy male divided into 2 groups:
trained endurance athletes (TS, n=9) and untrained individuals (US, n=8). Subjects performed
incremental cycle ergometric tests under normoxic and normobaric hypoxic conditions (1000,
1500, 2500, 3500, 4500 meters). Maximal power output (PO), heart rate (HR), arterial oxygen
