Nepal, from Lukla (2865m) to the Silver Pyramid (5050m) near the Everest Base Camp. EEG and
TCD were performed at baseline (100m), and at altitudes of 3440m and 5050m. SaO2, EtO2 and
Lake-Louise-AMS Score were evaluated twice daily. Of 26 mountaineers who reached 5050m,
we excluded those who developed symptoms of AMS prior to reaching or at 3440m and those
whose EEGs showed excessive artifacts. The 12 individuals who later developed symptoms of
AMS (Lake-Louise-AMS Score 3) showed between 100m and 3440m a significant (P<0.05)
increase of right temporal delta activity (powerspectral analysis) compared to the 10 healthy
subjects. In addition, the symptomatic climbers showed an increase of mean cerebral blood flow
velocity of the right medial cerebral artery (depth 55mm) between 3440m and 5050m compared
to the asymptomatic climbers (P<0.05). The increase of right temporal delta activity between
100m and 5050m in EEG power spectrum correlated negatively (r=-0.650, P<0.05) with EtCO2
decrease (-28%) in the symptomatic group. Thus, the alteration of right temporal brain function as
documented by EEG precedes the appearance of symptoms of AMS. Increased cerebral blood
flow in this area might reflect a compensatory mechanism due to increased demand of oxygen.
The negative correlation between EtCO2 and the EEG changes may reflect insufficient
compensatory hyperventilation. Acknowledgements: This study was supported by grants from the
Austrian Society of Alpine and High Altitude Medicine (ÖGAHM), Bayrische Sparkassenstiftung
and Münchner Zeitungsverlag. We thank RONAST, Comitato Ev-K2-CNR Bergamo for free use
of the Pyramid Laboratory, High Country Trekking and all participants.
44.
EFFECTS OF AM AND CGRP AFTER ACUTE EXPOSURE TO HIGH-ALTITUDE (
3
780M).
Gao Fen
1
, Chen Su-Juan
2
, Zhou Qing-Yu
1
, Wang Li-Ping
1
, Du Fa-Mao
1
. The Affiliated Hospital
of Qinghai medical college Xining, Qinghai, PRC
1
, The general Hospital of PLA Beijing
P.R.China
2
.
Recent experiments have shown that adrenomedulin (AM) and calcitonin gene-related
peptide (CGRP) play an important role in vasodilation and inhibiting the thickening of smooth
muscle cells in the pulmonary artery in hypoxic animals. The goal of this research was to study
whether the same results occur in humans when they experience acute exposure to high altitude.
[Methods] The AM and CGRP concentrations of artery (A) and vein (V) blood samples were
measured by radioimmunoassay in the control group (those residing at altitude 1100m) and in the
hypoxic groups [those who ascended to an altitude of 2260m and those who ascended to an
altitude of 3780m at 1d (H1d), 5d (H5d ) and 15d (H15d)].[Results]: 1. AM concentrations of A
and V continuously decreased after volunteers ascended to 2260m, and they were lowest in H1d.
Meanwhile, CGRP concentrations of A and V increased significantly (compared with CG
P<0.01).With an increase in altitude and hypoxic time, the AM concentrations of A and V
gradually increased and recovered at H15d to the level of the control group, and the CGRP
concentrations of A and V decreased significantly. The differences were significant when the
CGRP concentrations of H15d and H5d were compared and when the CGRP concentrations of
H1d and 2260m were compared. 2. There were notable differences between A and V
concentrations of AM H5d and CGRP H15d (P<0.01).3. There was a significant negative
correlation (r=-0.635, P<0.01) between AM and CGRP. Conclusion: 1.AM and CGRP both play
a role as vasodilating peptides in the regulation of pulmonary circulation during high altitude
hypoxic conditions. 2. When CGRP concentration increased, AM concentration decreased, which
maintained a dynamic balance. CGRP affected pulmonary circulation in the early phase of
hypoxia, and AM affected pulmonary circulation in the middle stages of hypoxia. 3. It is
suggested that AM and CGRP are extinguished in the lungs.
45.
CHANGES OF PEPTIDES IN ARTERY AND VEIN OF HEALTHY VOLUNTEERS AFTER
EXPOSURE TO HIGH ALTITUDE Gao Fen
1
, Gan Gui-Fen
1
, Zhang Lin-Bin
1
, Feng Xi-Ying
1
,
