erythropoietin activity were increased (3-fold and 10-fold, accordingly (p<0,05)) in patients, as
compared with healthy subjects. Initial data of the acid erythrograms in patients, especially the
qualitative cell ratio, also differed from the values from the healthy subjects. In the peripheral
blood of patients the population of superstable red cells was found that usually have not observed
in healthy people. Analysis of data obtained from trepanobiopsy have showed that before a ascent
31 patients (41%) had total aplasia of the bone marrow and 40 patients (57%) hypoplasia.
Baseline study of the bone marrow in patients has revealed some irritation of the erythroid cell
line with a growth in the count of immature and transitional forms. On the 10th day of adaptation
fetal hemoglobin concentration augmented 1,7-fold and on the 20th day 2,9-fold. The number
of reticulocytes increased by 28% on the 10th day of adaptation and by 68% on the 20th day, as
compared with the initial level. Reticulocytosis has been an objective sign of erythropoiesis
stimulation, as well as an enhancement of daily erythropoiesis by 35% (p<0,05). On the 20th day
of adaptation the number of superstable erythrocytes rose 3,7-fold (15,2% vs 4,1% at low
altitude) and remained on the same level at the end of adaptation. By the end of altitude
adaptation some decrease in reticulocytosis (131% of the initial values), daily erythropoiesis
(129% of the initial level) and serum erythropoietin activity (84% of the initial level) was found.
At the high altitude a tendency to a decrease in the number of young and maturating erythroid
cells was observed. After 40-day adaptation the amount of patients with hypoplasia of the bone
marrow decreased 3-fold. Thus, the effect of high altitude on erythropoiesis in patients with
aplastic anemia has manifested with reticulocytosis, an appearance of new population of young
superstable red blood cells with high content of fetal hemoglobin, as well as an increase of the
bone marrow cellularity. These data are evidence of activation of erythropoiesis at high altitude.
191.
HYPOXIA PRECONDITIONING REINFORCES TOLERANCE OF CA1 PYRAMID
NEURON OF HIPPOCAMPUS IN ADULT RAT BY PATCH CLAMPING STUDY. Shuanglai
Ren
1
, Tianming Gao
2
, Ming Fan
1
. Department of Brain Protection and Plasticity, Institute of
Basic Medical Sciences, Beijing, China
1
, Department of physiology, First Military Medical
Sciences, Guangzhou, China
2
.
Objective: to investigate the possible mechanism involved in the tolerance of CA1 Pyramid
Neuron of hippocampus. Methods: 1) the hippocampal brain slices (400µm) were prepared from
Wistar rats after being treated with hypoxic preconditioning (mimic 3000 m and 5000 m high
altitudes, 4 hours per day, two weeks). 2) With whole cell patch clamping recording, the recorded
neurons were treated with acute anoxia (95% N2 and 5% CO2). 3) The neuron dead index was
determined through their resting potentials depolarize about 0 mv by gap-free protocol of current
clamping mode. 4) The levels of mitochondrial membrane potential were deteced with CMX-
Rosamine, a mitochondrion tracker. 5) The activities of ATP-sensitive potassium channels were
observed with the channels special opener (diazoxide) and closer (5-hydroxydecanoic acid).
Results: 1) The dead time of neurons in 5000 m preconditioning group delayed compared with
the control. However, there was no significant difference between 3000m preconditioning group
and control. 2) Similarly, mitochondrial membrane potential of preconditioning group (5000 m)
was lower than the control, with little change in 3000 m group. 3) diazoxide directly depolarized
the mitochondria memberane, which could be reversed with 5-hydroxydecanoic acid.
Conclusions: Hypoxic preconditioning enhanced anoxic tolerance of hippocampal pyramid
neuron and stablized mitochondria membrane potential. The work was supported by key grant of
Natural Sciences Foundation of China (30393130)
192.
EFFECTS OF SILDENAFIL ON PULMONARY ARTERY PRESSURE AND GAS
EXCHANGE AT HIGH ALTITUDE. Jean-Paul Richalet
1
, Paul Robach
2
, Pierre Gratadour
3
,
Isabelle Pham
4
, Pascal Mollard
5
, Jérémy Cornolo
5
, Julien Brugniaux
5
, Aude Joncquiert-Latarjet6.
EA
23
6
3
, ARPE, Université Paris
13
, AP-HP, Bobigny, FranceEA
23
6
3
, ARPE, Université Paris
13
,
AP-HP,
1
, ENSA, Chamonix, France
2
, Hopital Hotel Dieu, Lyon, France
3
, EA
23
6
3
, Université
