single or coexist. Studies of CMS from China suggest that CMS is a public healthy problem in
the world's highlands, and should take extra attentions.
252.
PERIODIC BREATHING AND ARTERIAL BLOOD OXYGENATION IN TIBETANS AND
HAN AT A SIMULATED ALTITUDE OF 5000 M. Tianyi Wu
1
, Robert Plywaczewski
2
, Xiaoqin
Wang
1
, Pawel Sliwinski
2
, Jan Zielinski
2
. High Alt. Med. Res. Inst. Qinghai, P.R.China
1
, Institute
of TB and Lung Disease, Warsaw, Poland
2
.
Aim of our study was to investigate periodic breathing (PB) and arterial blood oxygenation in
Tibetans and Han in a hypobaric chamber at simulated altitude of 5000m. We studied 8 Tibetans,
mean age 26.6±7.4 years, and 6 Han, mean age 30.5±4.5 years. Two PSG were performed, 1st at
ambient altitude 2261m, the 2nd during acute exposure to altitude of 5000m (split night design).
Results are shown in table 1 and 2. Table 1. Periodic breathing and arterial blood oxygenation in
Tibetans and Han at the elevation of 2261 m, means±SD.
PB % of
sleep time
SaO2
mean (%)
SaO2 min
(%)
SaO2
mean REM
(%)
SaO2 mean
non-REM (%)
Tibet
ans
0.04± 0.01
91.9± 1.6
87.5± 2.5
92.6± 1.6
91.7± 1.8
Han
0.003
±0.005
92± 0.9
85± 3.5
92.5± 0.8
91.7± 1.0
P
NS
NS
NS
NS
NS
Table 2. Periodic breathing and arterial blood oxygenation in Tibetans and Han at the
elevation of 5000 m, means±SD.
PB % of
sleep time
SaO2
mean (%)
SaO2 min
(%)
SaO2
mean REM
(%)
SaO2 mean
non-REM (%)
Tibet
ans
53±21
68.3±5.3
56.9± 5.8
71.3± 4.8
67.5± 5.4
Han
44.6± 30.3
64.3±8
55.3± 9.3
65.8± 8.5
64± 7.8
P
NS
NS
NS
NS
NS
Conclusions: At 2261 m no differences in periodic breathing and oxygenation were found.
At 5000 m Tibetans had more periodic breathing and higher mean arterial blood saturation than
Han. Tibetans preserved better arterial blood oxygenation than Han during acute exposure to the
simulated altitude of 5000m.
253.
HYPOXIA REGULATES THE PROLIFERATION AND NEURONAL DIFFERENTIATION
OF P19 CELLS. Liying Wu
1
, Yan Wu
1
, Lingling Zhu
1
, Huiqing Zhao
1
, Aishi Ding
1
, Ming Fan
1
.
Department of Brain Protection and Plasticity, Institute of Basic Medical Sciences, Beijing,
China
1
The P19 line was derived from an embryonic carcinoma induced in C3H/He mouse. It is
pluripotent and efficiently induced to differentiate into neurons and glia in the presence of 500nM
retinoic acid (RA). Objective: Embryos naturally develop in hypoxia environment with only 3%
oxygen content. However, the effects of hypoxia on development of embryos are still not clear.
We used the P19 cells to investigate the effects of hypoxia on the proliferation and neuronal
differentiation of P19 cells. Methods: 1. Two-way classification of the hypoxia conditions:
intermittent (3% O2, 10 minutes for 3 days) and continuous hypoxia (3% O2, 24 hours). 2.
Incorporation of bromodeoxyuridine (BrdU) into cultured cells was use to measure the
proliferation of P19 cells. 3. A marker of mature neurons (NeuN, MAP2) and neuroepithelial
precursor cells (Nestin) was used to measure the neuronal differentiation. 4. Functional neurons
differentiated from P19 cells were identified by whole-cell patch clamp. Results: 1. Intermittent
hypoxia promoted the proliferation about up to 1.2fold, more neurons (>90%) were induced after
