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Biomedical subjects

M A Little

Publications and source records attributed to M A Little.

At least 37 records · Page 2Linked to original sources
PubMed1993

Growth of nomadic and settled Turkana infants of northwest Kenya.

Turkana tribespeople reside in a semi-arid savanna ecosystem in northwest Kenya. For over a decade, Ngisonyoka Turkana nomads have been studied within a multidisciplinary framework that embraces ecology, anthropology, and human population biology. Original research objectives of the South Turkana Ecosystem Project were to study nomads longitudinally and within the context of the dry savanna ecosystem. These objectives have been expanded to incorporate settled Turkana who were nomads in the recent past, but who, for a variety of reasons, have taken up a life of sedentary cultivation. The research described here focused on comparisons of growth patterns of nomadic and settled infants from birth to 24 months of age. Infants were measured (recumbent length, weight, head circumference, arm and calf circumference, and selected skinfolds) in 1989 and 1990. Settled infants were slightly longer, but nomadic infants were heavier and fatter. Head circumferences were the same. Some variation was observed by season and year of measurement (from comparative surveys). Both groups showed pronounced weight faltering after 6 months of age when compared with U.S. NCHS reference values. Head circumference faltering was moderate and recumbent length faltering was only slight after 12 months of age. Comparisons of Turkana infant growth in the two populations can contribute indirectly to a better understanding of infant nutritional status, probable morbidity, and other factors, some of which may be linked to female reproduction.

Anthropometry↗
PubMed1993

Pregnancy loss in Nomadic and settled women in Turkana, Kenya: a prospective study.

There have been few investigations of intrauterine mortality in non-Western populations that have used techniques capable of detecting early pregnancy loss. We report here the initial results of a prospective study of fetal loss among the Turkana of northwest Kenya. Over 300 nomadic and settled women provided early morning urine samples for 3 consecutive days. Chorionic gonadotropin (hCG), a marker for pregnancy, and markers of ovarian cyclicity (LH, PdG) were determined with solid-phase enzyme immunoassays. Pregnancy was detected in 11% of nomadic women and in 22% of sedentary women of reproductive age. Follow-up surveys revealed that 45% of all pregnancies among settled women were lost; nearly 70% of pregnancies detected in the first trimester were lost. In contrast, none of the nomadic women experienced fetal loss. Because of the small sample sizes, these results must be interpreted cautiously. Nevertheless, even a conservative estimate of the fetal loss rate among the settled women is high compared with Western experience. Anthropometric data suggest that nutritional stress may contribute to the difference between the two populations. There is also some indication that risk of fetal loss in the settled population is associated with parity. The high rate of loss among the settled women along with the difference between the nomadic and settled samples supports the contentions that there may be substantial variation among populations in intrauterine mortality and that the contribution of fetal loss to fertility differences among populations may be more important than has been suspected.

Adolescent↗
PubMed1986

Grip strength, muscle fatigue, and body composition in nomadic Turkana pastoralists.

Tests of hand grip strength and hand grip muscle fatigue were conducted on Ngisonyoka Turkana pastoralists of northwest Kenya to explore some of the functional relationships between activity and body composition. The test of maximal voluntary contraction (MVC) of hand grip flexors was conducted on 151 Turkana and 38 U.S. men and women. The fatigue test was conducted on the same number of subjects who were instructed to attempt to maintain 80% of the MVC for 90 seconds. The results of these tests, combined with arm measurements of size and body composition, were used to evaluate muscle size and strength relationships and to estimate muscle fiber type distribution in the forearm. MVC values of Turkana men were low by U.S. and European standards. The low values resulted from smaller Turkana muscle areas. MVC values of Turkana women were comparable to those of U.S. and European women, reflecting comparable muscle areas. The fatigue curves of Turkana and U.S. men and women suggest that slow-twitch aerobic muscle fibers predominate for the hand grip flexors of the Turkana pastoralists.

Adult↗
PubMed1980

Skin reflectance relationships with temperature and skinfolds.

Skin reflectance measurements were taken with six filters at a site on the medial aspect of the upper arm (underarm) prior to and following topical application of a cold compress. Skinfolds were measured at the underarm and triceps sites. The experiment was designed to test for effects of skin surface temperature and subcutaneous fat variations on skin color as determined by reflectometry. Topical cold-induced erythema of the skin produced marked declines in % reflectance at the shorter visible wavelengths over the range of violet, blue, and green, and only slight declines in % reflectance at the longer visible wavelengths (red range). This is consistent with the observation from past work that there is little hemoglobin absorptance at the red end of the visible spectrum. A positive relationship between the change in % reflectance following topical cold application and underarm skinfold was recorded. Hence, the thickeness of fat deposits may contribute to variation in skin reflectance. Since only large temperature differences influenced skin reflectance measurements, the need is not great for fieldworkers to control for surface temperature at the underarm site during skin reflectance survey.

Adipose Tissue↗
PubMed1976

Skin temperatures at the nape in infants at high altitude.

Skin temperatures were measured on three Quechua Indian infants resident at 4,000 meters above sea level in Peru. Nape temperatures were warmer than other skin sites, suggesting that the brown adipose tissue associated with non-shivering thermogenesis is metabolically active despite the reduced oxygen availability at high altitude. The question of the role of non-shivering thermogenesis in infant thermoregulation under the covariant stresses of hypoxia and cold is still open.

Adipose Tissue↗
PubMed1976

Local cold exposure of Andean Indians during normal and simulated activities.

Thermal resonses of Andean Indians were measured during several customary tasks associated with cold exposure in the highlands of southern Peru. These included surface temperature measurements of women while they washed clothing in the river and similar measurements of men while they constructed a diversion channel in the same river. A third test measured the effects of alcohol consumption on body temperatures during light activity. Women maintained slightly warmer hand than foot temperatures. Men maintained nearly equal hand and foot temperatures during the exposure period. Among male subjects the foot rewarmed at a faster rate than the hand. The results from the field studies compared favorably with results from earlier laboratory exposure tests. Comparisons between the river water exposure tests for males and females showed a consistent pattern where females maintained warmer hand and foot temperatures than males. These findings were in accord with previous laboratory studies among Quechua Indians and with the findings reported for other ethnic groups who experience natural cold stress. Alcohol ingestion appeared to have minimal effect in mitigating cold stress response during light activity. This finding was counter to earlier laboratory tests of resting subjects.

Activities of Daily Living↗