remaining 13 subjects without development of AMS (r=0.203, p=0.527). Conclusion: Early
correlation of relative MABP and V-MCA changes indicating loss of CA after ascents to 3440 m
may identify mountaineers at risk for later AMS during high altitude trekking. Supported by the
Austrian Society of Alpine and High Altitude Medicine (ÖGAHM), DWL (Sipplingen),
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.
7.
THE STRUCTURAL CHANGES OF PLACENTA FROM TIBETAN AND HAN
PREGNACIES AT HIGH ALTITUDE. Xihua Bai
1
, Shengxiu Ma
1
, Zhanhua Huang
2
. Qinghai
Medical College Hospital, Xining, Qinghai
1
, Qinghai Medical Colledge Hospital, Xining,
Qinghai
2
.
To explore the structural changes of the human term placenta at high altitude, we did a
morphological study on placentae from 37 native Tibetan and 50 immigrant Han pregnancies,
both living at 3719 m, and compared these with the placentae from Han women living at 2261 m
and at sea level. All pregnancies were matched for age, height, and weight. The mean newborn
weight in Tibetan and Han at 3719 m, and Han at 2261 m was 3166.7±441.6, 2961.8±489.4, and
3191.0±332.2 g, respectively. The Tibetan newborns were much heavier than the Han (P<0.01) at
3719 m. The light microscopic examination showed more villi characterized by the syncytial
node, a decreasing vascular syncytial membrane, fibrinoid necrosis, and thickening of the
basement membrane in Han placentae at 3719m and even at 2261 m, whereas the numbers of villi
and capillaries were increased in the placentae from Tibetans. Ultrastructural changes by
electron-microscope showed proliferation of syncytiotrophoblasts and cytotrophoblasts both in
Tibetan and Han, but it appeared early in Han, 39-40 weeks gestation, and 41-42 weeks gestation
in Tibetans. Dilatation and enlargement of endoplasmic reticula, and narrow papillary lumen were
shown in Han. In contrast, the vessel walls of capillaries were intact with rich blood cells in the
lumen in Tibetans. These placental characteristics of Tibetans were similar to those of the sea-
level placentae. The results suggest that Tibetans have an increased surface area of placenta and a
better diffusing capacity for oxygen than Han pregnancies at high altitude.
8.
CHANGE OF PLASMA ADM and CGRP, SERUM CT AND IGF-II IN ESSENTIAL
HYPERTENSION PATIENTS AT DIFFERENT ALTITUDES. Zhou Bai-Li
1
, Chang Rong
1
,
Chen Xiu-Ying
2
, Zhang Xue-Feng
1
, Xie Rong-Xing
1
, Qi Gang
1
. Qinghai Provincial People's
Hospital, Xining,, Qinghai, P.R. China
1
, Qinghai Provincial People's Hospital, Xining, Qinghai,
P.R. China
2
.
Changes in plasma adrenomedullin (ADM), calcitonin gene related-peptide (CGRP), serum
calcitonin (CT) and insulin-like growth factor II (IGF II) in patients with essential hypertension
(EH) and normal subjects from different altitudes were investigated. Plasma ADM, CGRP, serum
CT, IGF II were measured by radioimmunoassay method in 94 patients with EH (28 lowland, 39
moderate altitude and 27 from high altitude respectively) and 115 normal subjects as controls (40
from lowland, 45 from moderate and 30 from high altitude). The results showed that plasma
ADM, serum CT and IGF II were higher in patients with EH than those of the control group
(p<0.01). The plasma ADM and serum CT were lower in control groups from lowland than in
control groups from moderate and high altitudes (p<0.001). The serum CT was lower in patients
with EH from lowland than in patients from moderate and high altitudes (p<0.01). The plasma
CGRP was significantly lower in patients from high altitude with EH than that of control groups
(p<0.001). The plasma CGRP was significantly lower in the control groups from high altitude
than in those from lowland and moderate altitude (p<0.001). The plasma CGRP was significantly
higher in patients from lowland areas than in those from high and moderate altitude (p<0.001).
The increasing synthesis of plasma ADM, serum CT, IFG II and the decreasing secretion of
CGRP may occur in order to regulate blood pressure in patients with EH. The disorder was more
serious with increasing altitude.
