Evelia Edith Oyhenart

Parasitosis intestinales en poblaciones Mbyá-Guaraní de la Provincia de Misiones, Argentina: aspectos epidemiológicos y nutricionales

Intestinal parasite infestation in indigenous Mbya-Guarani communities in Misiones, Argentina, was described and associated with nutritional status and environmental and cultural factors. The results were compared with those from Takuapi, a neighboring indigenous population, and the nearest urban population, Aristobulo del Valle. The Ritchie, Willis, and Kato Katz techniques were used to analyze the stool samples. Anthropometric parameters were analyzed and earth samples processed. From a total sample of 296 individuals analyzed in the four populations, 100 (87.7%), 63 (88.7%), 49 (96.1%), and 50 (82%) were infested in Kaaguy Poty, Yvy Pyta, Takuapi, and Aristobulo del Valle, respectively. 84% of infested individuals had multiple parasites. The 43% of the individuals presented malnutrition, and 87% of these were infested. There was an association between use of latrines and Giardia lamblia (p < 0.01); open-air defecation, lack of footwear, and hookworms (p < 0.01); and housing type and total helminthes (p < 0.01). Earth samples were contaminated with parasites. The results suggest the relationship between environmental contamination and high prevalence of intestinal parasites in these human populations.

Developmental plasticity in covariance structure of the skull: effects of prenatal stress

Environmental perturbations of many kinds influence growth and development. Little is known, however, about the influence of environmental factors on the patterns of phenotypic integration observed in complex morphological traits. We analyze the changes in phenotypic variance–covariance structure of the rat skull throughout the early postnatal ontogeny (from birth to weaning) and evaluate the effect of intrauterine growth retardation (IUGR) on this structure. Using 2D coordinates taken from lateral radiographs obtained every 4 days, from birth to 21 days old, we show that the pattern of covariance is temporally dynamic from birth to 21 days. The environmental perturbation provoked during pregnancy altered the skull growth, and reduced the mean size of the IUGR group. These environmental effects persisted throughout lactancy, when the mothers of both groups received a standard diet. More strikingly, the effect grew larger beyond this point. Altering environmental conditions did not affect all traits equally, as revealed by the low correlations between covariance matrices of treatments at the same age. Finally, we found that the IUGR treatment increased morphological integration as measured by the scaled variance of eigenvalues. This increase coincided and is likely related to an increase in morphological variance in this group. This result is expected if somatic growth is a major determinant of covariance structure of the skull. In summary, our findings suggest that environmental perturbations experienced in early ontogeny alter fundamental developmental processes and are an important factor in shaping the variance–covariance structure of complex phenotypic traits.

Parasitosis intestinales en niños de edad preescolar y escolar: situación actual en poblaciones urbanas, periurbanas y rurales en Brandsen, Buenos Aires, Argentina

MARIA LORENA ZONTA*, GRACIELA TERESA NAVONE* y EVELIA EDITH OYHENART** Centro de Estudios Parasitologicos y de Vectores (CEPAVE-CONICET-UNLP); Calle 2 No. 584, 1900 La PlataBuenos Aires, Argentina. Catedra de Antropologia Biologica IV. Facultad de Ciencias Naturales y Museo, UNLP.* Catedra de Antropologia Biologica IV. Facultad de Ciencias Naturales y Museo, UNLP; Centro de Investigaciones enGenetica Basica y Aplicada, UNLP (CIGEBA) - CONICET.

Effect of Undernutrition on the Cranial Growth of the Rat

The cumulative effect of undernutrition on successive generations was tested. The cranial growth of three generations of undernourished rats (F1, F2, F3) was compared to that of the parental generation (P), in order to (1) measure the extent to which the growth of each facial and neurocranial functional component was retarded when animals were undernourished and (2) determine whether any cumulative effect between generations can be found. The P generation was fed ad libitum, and the undernourished generations were fed 50% (F1) and 75% (F2 and F3) of the parental diet. Nine radiographs were taken from the age of 20–100 days. The length, width and height of the neurocranial and facial components were measured on each radiograph. Neurocranial (VNI), facial (VFI), and neurofacial (NFI) indices were calculated. Data were processed by the Kruskal-Wallis and Kolmogorov-Smirnov tests. An impairment in neurocranial and facial growth was found, the latter being more affected than the former in F1. At variance, the neurocranium was more affected than the face in F2 and F3, resulting in variations of the shape of the skull. A cumulative effect of moderate transgenerational undernutrition was evident and points to the need for further analysis on this topic.

Socioenvironmental Conditions and Nutritional Status in Urban and Rural Schoolchildren

We analyzed the nutritional status of urban and rural schoolchildren from Mendoza (Argentina), but avoided rural and urban categorization by generating subpopulations as a function of their socioenvironmental characteristics. We transformed weight and height data into z‐scores using the CDC/NCHS growth charts; defined underweight, stunting, and wasting by z‐scores of less than −2 SD; and calculated overweight and obesity, according to the cutoff proposed by the International Obesity Task Force. Socioenvironmental characteristics included housing, public services, parental resources, and farming practices; we processed these variables by categorical principal‐component analysis. The two first axes defined four subgroups of schoolchildren: three of these were associated with urban characteristics, while the remaining subgroup was considered rural. Nutritional status differed across groups, whereas overweight was similar among the groups and obesity higher in urban middle‐income children. Urban differences were manifested mainly as underweight, but rural children exhibited the greatest stunting and wasting. Thus, the negative effects of environment on nutritional status in children are not restricted to poor periurban and rural areas, though these are indeed unfavorable environments for growth: some urban families provide children with sufficient quantity and diversity of foods to expose them to obesity. By contrast, the more affluent urban families would appear to have greater possibilities for allowing their children to adopt a healthy life‐style. Although the causes of differences in nutritional status between middle‐ and high‐income urban groups are not clear, these determinants probably involve economic as well as educational influences. Am. J. Hum. Biol., 2008.

Effects of Environmental Perturbations During Postnatal Development on the Phenotypic Integration of the Skull

Integration and modularity are fundamental determinants of how natural selection effects evolutionary change in complex multivariate traits. Interest in the study of the specific developmental basis of integration through experimental approaches is fairly recent and it has mainly focused on its genetic determinants. In this study, we present evidence that postnatal environmental perturbations can modify the covariance structure by influencing the variance of some developmental processes relative to the variances of other processes that contribute to such structure. We analyzed the effects of the reduction of nutrient supply in different ontogenetic stages (i.e. before and after weaning, and from birth to adulthood) in Rattus norvegicus. Our results show that this environmental perturbation alters the phenotypic variation/covariation structure of the principal modules of the skull (base, vault, and face). The covariance matrices of different treatment groups exhibit low correlations and are significantly different, indicating that the treatments influence covariance structure. Postnatal nutrient restriction also increases the variance of somatic growth. This increased variance drives an increase in overall integration of cranial morphology through the correlated allometric effects of size variation. The extent of this increase in integration depends on the time and duration of the nutritional restriction. These results support the conclusion that environmental perturbations can influence integration and thus covariance structure via developmental plasticity.

Estado nutricional y composición corporal de niños pobres residentes en barrios periféricos de La Plata, Argentina

OBJECTIVES: To evaluate nutritional status and body composition as indicators of quality of life among poor children served by neighborhood soup kitchens in La Plata, Argentina. METHODS: From April to November 2004, we conducted a cross-sectional study of 608 healthy children from 1-11 years of age who were being served by two neighborhood soup kitchens in the outlying areas of the city of La Plata. The sample was stratified by age and sex. Height-for-age, weight-for age, and weight-for-height, were measured, as well as BMI, muscle mass and adipose tissue. Z-scores were computed for the data. Odds ratios and the respective 95% confidence intervals were calculated. RESULTS: Prevalence of low weight-for-age was 9%; low weight-for-height, 3%; and low height-for-age, 15%. The prevalence of overweight and obesity were 12.5% and 7.1%, respectively. Among the study sample, 47.2% had low muscle mass and 20.4% had low adipose tissue. Among overweight and obese children, adipose tissue was 34.3% higher than that of the reference population, while muscle mass was 12.5% lower. CONCLUSIONS: Undernutrition and obesity are both found among the community of children studied. The high prevalence of delayed growth (i.e., low height-for-age), undernutrition (i.e., low weight-for-age), and the acute lack of muscle mass even among overweight and obese children, seem to be part of the consequences of an inevitable process that unfolds in the face of adverse living conditions.

Morphometric and ultrastructural analysis of different pituitary cell populations in undernourished monkeys

Undernutrition elicited by a low-protein diet determines a marked reduction of hypophyseal activity and affects the function of the respective target organs. The objective of the present investigation was to study the ultrastructural and quantitative immunohistochemical changes of the different pituitary cell populations in undernourished monkeys that had been previously shown to have significant changes in craniofacial growth. Twenty Saimiri sciureus boliviensis monkeys of both sexes were used. The animals were born in captivity and were separated into two groups at one year of age, i.e., control and undernourished animals. The monkeys were fed ad libitum a 20% (control group) and a 10% (experimental group) protein diet for two years. Pituitaries were processed for light and electron microscopy. The former was immunolabeled with anti-GH, -PRL, -LH, -FSH, -ACTH, and -TSH sera. Volume density and cell density were measured using an image analyzer. Quantitative immunohistochemistry revealed a decrease in these parameters with regard to somatotrophs, lactotrophs, gonadotrophs and thyrotrophs from undernourished animals compared to control ones. In these populations, the ultrastructural study showed changes suggesting compensatory hyperfunction. On the contrary, no significant changes were found in the morphometric parameters or the ultrastructure of the corticotroph population. We conclude that in undernourished monkeys the somatotroph, lactotroph, gonadotroph, and thyrotroph cell populations showed quantitative immunohistochemical changes that can be correlated with ultrastructural findings.

Growth of functional cranial components in rats submitted to intergenerational undernutrition

The aim of the present study was to discover how intergenerational undernutrition affects the growth of major and minor functional cranial components in two generations of rats. Control animals constituted the parental generation (P). The undernourished generations (F1 and F2) were fed 75% of the control diet. Animals were X‐rayed every 10 days from 20 to 100 days of age. The length, width and height of the major (neurocranium and splanchnocranium) and minor (anterior‐neural, middle‐neural, posterior‐neural, otic, respiratory, masticatory and alveolar) cranial components were measured on each radiograph. Volumetric indices were calculated to estimate size variations of these components. Data were processed using the Kruskal–Wallis and Kolmogorov–Smirnov tests for two samples. Impairment in splanchnocranial and neurocranial growth was found, the latter being more affected than the former in F1. Comparison between F2 and F1 animals showed cumulative effects of undernutrition in both major and minor components (anterior‐neural, respiratory, masticatory and alveolar in males, and middle‐neural and respiratory in females). Such differential effects on minor components may reflect a residual mechanical strain resulting from the linkage between components. This phenomenon was clearly observed in the neurocranium and could be understood as an adaptive response to the demands of the associated functional matrices.

Nutritional status in two Mbyá-Guaraní communities from misiones (Argentina).

Growth and nutritional status of children and adults in two Mbyá-Guaraní communities from Argentina, was assessed. Height, weight, sitting height, upper arm circumference, triceps and subscapular skinfold were measured on 120 individuals aged from 2 to 60 between March and May, 2001. Data were transformed to z-scores using United States references (NHANES I and NHANES II). A z-score of less than -2 was used as the cut-off point to determine the prevalence of stunting and wasting respectively. Mean z-scores for weight, height, and upper arm circumference lie below the reference (0 > Z > -3), while in sitting height ratio and muscular area for females they were above the US standard (0 < Z < 2). Skinfold thicknesses and muscular area for males were similar to the reference (2 > Z > -1). Our findings are in agreement with others South American Indian research that the prevalence of stunting (36.7%) is significantly higher than wasting (1.8%). The presence of parasitic infections and nutritional environment previously described in this population could be related to the short stature.