Yvette Conley
1
, Valerian Kagan
1
, Stefan Ryter
1
, Augustine Choi
1
. University of Pittsburgh,
Pittsburgh, Pennsylvania, USA
1
.
There is emerging evidence that the pattern of hypoxia is a critical factor in determining
physiologic response, with intermittent hypoxia (IH) being a more potent stimulus than
continuous hypoxia (CH). Aims: 1.Compare cardiovascular (C-V) effects of IH vs. CH (SpO2 80-
90%); 2. Compare the effect of IH and CH on circulating and exhaled biomarkers. 3. Explore the
relationship between the C-V impact of IH/CH and biological markers. Design & methods:
Within-subjects repeated measures design with subjects (18-45 year old healthy male volunteers)
participating in 3 blocks: 1) control session (60 minutes of normoxia); 2) three consecutive days
of IH (six 10 minute exposures to hypoxia with SpO2 = 80-90%, and 10 minutes of normoxia
between each hypoxia exposure); and 3) three consecutive days of CH (60 continuous minutes of
SpO2 = 80-90%). Systolic, diastolic, and mean blood pressure, heart rate, SpO2, and end tidal
CO2 were monitored and recorded. Exhaled nitric oxide (NO), carbon monoxide (CO), and serum
nitrite levels were measured pre and post hypoxia exposure. Data were analyzed using a
2 x 3 x 2 ANOVA. Results are reported for the 5 subjects who have completed data collection
to date. Heart rate (p= 0.016), systolic blood pressure (p=0.034) and exhaled end tidal NO (p=
.013) were higher post-hypoxia (regardless of IH/CH or day 1, 2 and 3). During IH, serum nitrite
levels of 4 subjects were significantly higher (p=0.001) across days 1-3 and there was a
significant interaction (p = 0.007) post-hypoxia exposure across days 1-3. This preliminary
analysis suggests that short-term IH and CH episodes in normal males produces elevated SBP,
HR, and exhaled NO post-exposure. Analysis of serum nitrite levels from 4 subjects across days
1, 2, and 3 during IH may provide evidence of regulation of gene expression.
195.
COORDINATIVE EXPRESSION OF CYTOCHROME C OXIDASE SUBUNITS IN
MITOCHONDRIA FROM CEREBRAL CORTEX OF RATS EXPOSED TO HYPOXIA AND
CHLORAMPHENICOL ADMINISTRATION. Song Rong
1
, Liu Junze*
1
, Chen Lifeng
1
.
Department of Pathophysiology, Institute of High Altitude Military Medicine, The Third Military
Medi
1
.
Mitochondral respiration relies on respiration chain complex encoded by mtDNA and nDNA.
This study objective is to understand the coordinative expression of cytochrome c
oxidase(CytOX) subunits encoded by the two genome during hypoxia exposure and
Chloramphenicol(CAP) administration, a specific inhibitor for mitochondrial protein synthesis.
Adult male Wistar rats were administrated with CAP (50mg/kg, twice a day) for 7 days before
sacrificed by decapitation. Control and CAP-administrated animals were exposed to a hypobaric
chamber simulating 5000m high altitude for 23 hours and 30 days respectively. Rat brain was
removed and the cerebral cortex mitochondria were isolated by centrifugation programme.
CytOX subunit_and _ expression were detected by RT-PCR and Western blot analysis. The
results showed that CytOX _mRNA state level decreased significantly during hypoxia exposure,
restored to normal in CAP-administrated rats. CytOX _mRNA expression had no significant
change among all animals. A decreased CytOX _protein and an elevated ratio of subunit _/_was
observed during hypoxia exposure, also in CAP-administrated rats. There were no significant
change of CytOX _and the ratio of _/_in CAP-administrated rats during hypoxia exposure. But a
mutual effect by CAP-administration and hypoxia was observed. CytOX _ protein unchanged
among all animals. These results suggested that the regulation of CytOX subunit expression
during acute or chronic hypoxia exposure might occur at post-transcription (or translation) level
in mitochondrial genome, while both at transcription and translation level in nuclear genome.
CAP-administration may modulate the coordinative expression of CytOX subunit by mtDNA and
nDNA during hypoxia exposure. Key words: cytochrome c oxidase; hypoxia; Chloramphenicol;
coordinative expression
196.
CLINICAL STUDY OF 55 CASES OF HIGH ALTITUDE HEART DISEASE IN CHILDREN
IN QINGHAI . Ma Ru-Yan
1
, Ying Pang
1
, Ge Ri-Li
2
. Dept. of Cardiology, Qinghai Provincial
