PubMed · 5958170
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E R Dickinson, M J Piddington, T Brain. 1966. Project Olympics.. https://pubmed.ncbi.nlm.nih.gov/5958170/
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Standard haematological values have been calculated for female Holstein and Brown Swiss cattle kept at high altitudes in the Andean Sierra. Overall mean values were 5.9 x 10(12) l-1 for the red cell count, 0.321 l-1 for the packed cell volume, 9.6 gdl-1 for the haemoglobin concentration, 55.0 femtolitres for the mean corpuscular volume, 30.5 gdl-1 for the mean corpuscular haemoglobin concentration and 16.7 pg for mean corpuscular haemoglobin. Red cell indices tended to be higher in Holstein cattle than in Brown Swiss kept at the same altitude and were higher in cattle kept at higher altitudes. Mean white cell parameters were 9.7 x 10(9) l-1 for total white cells, 2.6 x 10(9) l-1 for neutrophils, 0.086 x 10(9) l-1 for bands, 6.3 x 10(9) l-1 for lymphocytes, 0.7 x 10(9) l-1 for eosinophils, 0.073 x 10(9) l-1 for monocytes and 0.001 x 10(9) l-1 for basophils.
OBJECTIVE: To study the association between high altitude and spontaneous preterm birth. METHODS: Eleven placentas from cases of high altitude (3000 m) spontaneous preterm deliveries with no clinical predisposing cause were collected in Abha, a city of southern Saudi Arabia. The placentas were examined histologically using sections stained by periodic acid-Schiff and hematoxylin-eosin. The mean percentages of villi with syncytial knots and cytotrophoblastic cells were determined. RESULTS: Histology of the placenta samples showed an excessive formation of syncytial knots (45.4 +/- 13.3%) and cytotrophoblastic cells (52.7 +/- 15.2%) at terminal villi. CONCLUSION: The enhanced formation of syncytial knots and cytotrophoblastic cells is a histological feature of placental hypoxia, which may be secondary to maternal hypoxia resulting from high altitude hypoxia. Since placental hypoxia is associated with an increased incidence of spontaneous preterm birth, we suggest that high altitude may be involved in the etiology of spontaneous preterm birth.
To determine whether nocturnal periodic breathing (PB) at altitude is due primarily to unstable control of ventilation or the inability to maintain stable sleep states, we performed visual and computer analyses of the electroencephalographic and respiratory records of healthy volunteers at simulated altitudes of 4572, 6100 and 7620 m. Transient arousals were associated with < 52% of the apneas identified; thus, the PB cycle was not always associated with transient arousal. Following the termination of oxygen breathing, the reinitiation of PB was not dependent on the occurrence of arousal as the primary event. The transition from apnea to breathing preceded the appearance of arousal by approximately 1 to 4 sec. Ventilatory drive in the breaths immediately following arousal was significantly larger than corresponding control breaths, matched for SaO2. Our findings suggest that altitude-induced PB is unlikely to result from primary fluctuations in state. Arousals promote the development of PB with apnea and help to sustain these episodes, but are not necessary for their initiation.