Introduction Periodic breathing (PB) at altitude represents an example of instability in the
chemical control of breathing. Instability of a system (e.g. respiratory control) is more likely if the
gain of the negative feedback (e.g. hypoxic ventilatory response, HVR) is high. The predictive
value of HVR in determination of susceptibility to acute mountain sickness (AMS) is unclear. We
therefore hypothesized: Volunteers with a brisk HVR show more PB A brisk HVR increases
AMS by increasing PB Methods and Subjects 42 volunteers participated in studies before and
during a 6 week trek to Chamlang basecamp, Nepal, ascending to 5100m over 19-22 days. They
underwent (1) Pre-expedition sea-level assessment of HVR (Rebuck and Campbell 1974), (2)
twice daily Lake Louise AMS symptom scoring during the expedition and (3) sleep studies within
3 nights of arrival at basecamp. Results There was no significant relationship between sea-level
HVR and percentage time in PB (p = 0.15). There was no significant difference in HVR between
9 subjects who remained free of AMS (HVR 0.72 + 0.56 L/SaO2%) and 33 subjects who suffered
AMS at some point during the ascent (0.63 + 0.43 L/SaO2%). Discussion Unlike Lahiri et al
(1983) and Goldenbery et al (1992) we did not find a correlation between HVR and PB. This may
be as our volunteers ascended slowly and so were partially acclimatized, not all sleep studies
were carried out on the first night at basecamp. West et al (1986) also found no correlation
between HVR and PB. HVR appears not to be a key determinant of AMS, at least in trekkers
ascending slowly to altitude.
153.
CHANGES IN TUMOR NECROSIS FACTOR AND INTERLEUKIN-6 IN NORMAL
SUBJECTS AT HIGH ALTITUDE. Ren Min
1
, Feng Jiang-Ming
1
, Shi Qing-Wu
1
, Wang Li
1
,
Chen Shao-Bin
2
, Han Guo-Xiong
1
, Ai Guo
1
, Yu Mei-Hua
1
, Wu Wei-Ming
3
. The People's
Hospital of QingHai; Xining Qinghai,P.R.China
1
, The People's Hospital of QingHai; Xining
Qinghai, P.R.China
2
, The People's Hospital of QingHai; Xining Qinghai, P.R.China
3
.
The objective of this paper is to discuss changes in levels of tumor necrosis factor (TNF) and
interleukin-6 (IL-6) at different altitude. We measured the content of serum TNF and IL-6 of
normal subjects from Beijing (100m), Germu (2800m) and Tuotuo River (4700m) by radio-
immunoassay. The results showed that the levels of IL-6 were 99.13+32.52pg/ml in Beijing,
120.48+36.13pg/ml in Germu and 131.52+33.22pg/ml in Tuotou River, respectively. The levels
of TNF were 99.13+32.52ng/ml in Beijing, 120.48+36.13ng/ml in Germu and
131.52+33.22ng/ml in Tuotou River, respectively. Results showed that the levels of TNF and IL-
6 increased with increasing altitude and that there were significant difference in these values at
different altitudes (p<0.05). These measurements provided the normal values of TNF and IL-6 at
different altitudes. As a cell factor with multiple functions, TNF and IL-6 may be related to
hypoxia at high altitude and may result in damage of body tissues.
154.
CHANGES IN ERYTHROPOIETINLEVELS IN NORMAL SUBJECTS AT DIFFERENT
ALTITUDES. Ren Min
1
, Feng Jian-Ming
1
, Shi Qing-Wu
1
, Shen Kuo
1
, Chen Shao-Bin
1
, Wan Li
2
,
Ai Guo
1
, Han Guo-Xiong
1
, Sun Zhi-Xin
1
, Yu Mei-Hua
3
, Wu Wei-Ming
1
. The People's Hospital
of QingHai; Xining Qinghai, P.R.China
1
, The People's Hospital of QingHai; Xining Qinghai,
P.R.China
2
, The People's Hospital of QingHai; Xining Qinghai, P.R.China
3
.
The purpose of the paper is to study the changes in erythropoietin levels in normal subjects at
different altitudes. Erythropoietin levels were measured by radio-immunoassay. The samples
were taken from normal subjects in the Germu area (2800m) and in the Tuotuo River area
(4700m) as well as patients at 4700m with erythromatosis. The results showed that the levels of
EPO of the subjects were 22.9+11.09pg/ml (Beijing, 100m), 35.9+24.35pg/ml (Germu, 2800m)
and 42.65+39.54pg/ml (Tuotuo River, 4700m), respectively. At the same time, the content of
EPO in erythromatosis patients in Tuotuo River was 48.73+64.72pg/ml. This shows that EPO of
the normal subjects increased with increasing altitude and that there were significant differences
in EPO levels among the different groups (p<0.05). This also indicats that the levels of EPO in
the patients with erythromatosis were higher than that of normal subjects in the highest altitude
