High-altitude haematology: Quechua-Aymara comparisons.

Haematological studies have been carried out at various altitudes between 450 m and 4800 m, on two separate human groups (Quechuas and Aymaras) living in South America. Changes in the haematological parameters do not develop linearly in relation to the attitude. Th impact of chronic hypoxia on erythropoiesis is greater above 3000 m. The haemogram varies quantitatively and not qualitatively (mean corpuscular volume and mean haemoglobin concentration remain constant). The haematological study also reveals the greater adaptability to high altitude of the Aymaras, an adaptability characterized by an increase in red cell count and concentration and a decrease in red cell volume. The adaptative phenomena observed in the Quechuas are reversible, whereas they persist in the Aymaras when they migrate to the lowlands (450 m).

Methaemoglobin and erythrocyte reducing systems in high-altitude natives.

The stress of chronic hypobaric hypoxia present at high altitudes induces a series of adaptive changes in the intermediate metabolism in erythrocytes of high-altitude natives. Aymaras of the high Andean Plateau are shown to have within erythrocytes: (a) increased activity of NADH2 (GAPDH) generating stages, (b) decreased activity of NADH2 (LDH) consuming steps, (c) significantly increased methaemoglobin content, and (d) a large increase in the level of reduced glutathione. These alterations occur also in persons of the same ethnic group residing at low altitude. There is, however, only a moderate elevation of classic haematological parameters (erythrocyte count, haemoglobin and haematocrit) in highland natives. The functional implications of these metabolite changes are discussed with respect to regulation of erythrocyte metabolism.

Serum and red cell enzyme polymorphisms in six Amerindian tribes.

Data are presented on red cell and serum enzyme types in six Amerindian tribes in Central and South America of whom the Siriono, Chipaya and Jicaque are markedly inbred. The data obtained in three systems (AcP, PGM, 6PGD) show aberrant phenotype and gene frequencies in these three tribes by comparison with other Amerindian populations. Uniformity of the results was observed in the following red cell enzymes: AK, G6PD, PGM2, ADA and LDH.

Serum and red cell enzyme variants in an Amerindian tribe: the Sirionos (Eastern Bolivia).

Blood samples from 109 Siriono (Eastern Bolivia) belonging to the Tupi-Guarani group were investigated for enzyme variants in the following systems: glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, adenylate kinase, phospho-glucomutase (locus 1 and 2), acid phosphatases, lactate dehydrogenase, NADH diaphorase, pseudocholinesterase (E1 and E2 locus), and serum alkaline phosphatase. The most relevant observations are: (1) A relative lack of polymorphism, a characteristic feature of the Amerindian populations studied up to now. These data are consistent with the hypothesis of a 'common ancestral background' in Indian populations whatever the degree of sociocultural and linguistic diversity, and the geographical distances. (2) Specific traits due to the frequency of alleles in some systems confer to that tribe a particular position among Amerindians. The effects of genetic drift may be postulated in order to explain the high rate of PGM and 6PGD polymorphism. Furthermore, in that small community, the disappearance of some alleles (pa gene) can plausibly be explained in terms of a balanced influence of mutational and selective pressure.