Open ISEmeter: An open hardware high-impedance interface for potentiometric detection

In this work, a new open hardware interface based on Arduino to read electromotive force (emf) from potentiometric detectors is presented. The interface has been fully designed with the open code philosophy and all documentation will be accessible on web. The paper describes a comprehensive project including the electronic design, the firmware loaded on Arduino, and the Java-coded graphical user interface to load data in a computer (PC or Mac) for processing. The prototype was tested by measuring the calibration curve of a detector. As detection element, an active poly(vinyl chloride)-based membrane was used, doped with cetyltrimethylammonium dodecylsulphate (CTA(+)-DS(-)). The experimental measures of emf indicate Nernstian behaviour with the CTA(+) content of test solutions, as it was described in the literature, proving the validity of the developed prototype. A comparative analysis of performance was made by using the same chemical detector but changing the measurement instrumentation.

Predicting percentage body fat through waist-to-height ratio (WtHR) in Spanish schoolchildren

OBJECTIVE

To analyse the association between waist-to-height ratio (WtHR) and body fat and to develop predictive adiposity equations that will simplify the diagnosis of obesity in the paediatric age group.

DESIGN

Cross-sectional study conducted in Spain during 2007 and 2008. Anthropometric dimensions were taken according to the International Biology Program. The children were classified as underweight, normal weight, overweight or obese according to national standards of percentage body fat (%BF). WtHR differences among nutritional status categories were evaluated using ANOVA. Correlation analysis and regression analysis were carried out using WtHR as a predictor variable for %BF. A t test was applied to the results obtained by the regression model and by the Siri equation. The degree of agreement between both methods was evaluated by estimating the intra-class correlation coefficient.

SETTING

Elementary and secondary schools in Madrid (Spain).

SUBJECTS

Girls (n 1158) and boys (n 1161) from 6 to 14 years old.

RESULTS

WtHR differed significantly (P < 0.001) depending on nutritional status category. This index was correlated (P < 0.001) with all adiposity indicators. The mean %BF values estimated by the regression model (boys: %BF = 106.50 × WtHR - 28.36; girls: %BF = 89.73 × WtHR - 15.40) did not differ from those obtained by the Siri equation. The intra-class correlation coefficient (0.85 in boys, 0.79 in girls) showed a high degree of concordance between both methods.

CONCLUSIONS

WtHR proved to be an effective method for predicting relative adiposity in 6-14-year-olds. The developed equations can help to simplify the diagnosis of obesity in schoolchildren.

Variability of six STR loci in populations from Central Spain

Allele frequency distributions of six short tandem repeat (STR) loci, HUMTH01, HUMFES/FPS, HUMTPOX, HUMVWF/A31, HUMF13B, and HUMLPL, were determined in a population (101 individuals) of the Vera-Jerte region in West Central Spain. Amplified products were electrophoresed on denaturing polyacrylamide gels and silver-stained. The exact test demonstrated that none of the six loci deviated from Hardy-Weinberg equilibrium. R-matrix analysis in relation to other European samples agrees well with genetic distance results of Reynolds et al. (1983). Comparisons show that our population comes reasonably well within the range of variation of other European samples, and that the representation of these samples on the genetic map indicates a close relation between geographical location and distribution in the diagram.

C282Y and H63D mutation frequencies in a population from central Spain

OBJECTIVES

To determine the frequency of hereditary hemochromatosis gene mutations, C282Y and H63D, from 125 autochthonous blood donors originating from a Central region of Spain, to provide epidemiological data about HFE gene in the Iberian Peninsula.

METHODS

DNA extracted from blood samples was analyzed by PCR-RFLP. Restriction enzymes were Snab I and Bcl I for C282Y and H63D, respectively. Results were visualized with Ethidium Bromide staining after gel electrophoresis.

RESULTS AND DISCUSSION

C282Y frequency was 0.02 and that of H63D was 0.16. Result for C282Y mutation falls within the range of variation of the Mediterranean populations. H63D frequency agrees with those reported for other European populations. In both cases frequencies obtained are the lowest of compared Spanish data.

CONCLUSIONS

This study is useful to compare expected versus presented C282Y and H63D frequencies in Spanish populations and to contribute to the knowledge of Spanish variability, rarely analyzed until now for HFE gene mutations.

Trend in menarcheal age in Spain: rural and urban comparison during a recent period

Menarcheal age of a sample of rural (n = 342) and urban (n = 469) girls with ages ranging from 9 to 16 years from Madrid province was analysed. Results, obtained through the status quo method and probit analysis (age 12.79 SD 1.04 in Madrid city and 12.90 SD 1.03 in rural sample), were compared with data from previous studies carried out in the same area, as well as those from other regions of the Iberian Peninsula. The aim of these comparisons was to establish the variability of menarche in the recent past, considering physical environment, degree of urbanization and socio-economic development. Decline in menarcheal age was detected and, in general, a tendency towards similar means among Spanish populations in the period studied.

Red-green colour blindness in the Tormes-Alberche Valley (Avila-Central Spain)

A population from a Central Spanish region (Tormes-Alberche Valley) has been investigated for the presence of red-green colour vision defects. A sample of 998 subjects (469 male and 529 female) was analyzed. To identify colour vision defects, Ishihara test plates were used. The red-green colour blindness percentage obtained was 4.69 +/- 0.976% for males (2.13% protan and 2.56% deutan types) and none of the females tested were found to be colour blind. These results are within the variation range of Mediterranean populations and lower than the usual frequencies among non-Mediterranean European samples.

Body composition of rural and urban children from the central region of Spain

Body composition components are considered in a cross-sectional sample of 2564 children (age range 6-14 years) from Central Spain. The sample was divided depending on rural or urban residence. Weight, and skinfold at the triceps, biceps, subscapular and suprailiac site were measured. Body composition was represented by percentage fat (%F), lean body mass (LBM), fat mass (FM) and sum of skinfolds (SSK). Sex differences were found to be highly significant for all variables and rural-urban differences were small. Rural boys show slightly larger fat content, in %F, FM and SSK, than their urban peers, but significant (p < 0.05) differences appear only for SSK. No statistically significant environmental effect was found for LBM. The improvement of living conditions, the urban influence on the rural area and the degree of urbanization of the urban settlement are suggested as the main determinants influencing obtained results.

Inbreeding patterns in the Gredos Mountain Range (Spain)

The relationships among the frequency of consanguineous marriages, inbreeding coefficient, period, village size, and altitude are analyzed for three rural valleys belonging to the Sierra de Gredos (central Spain). These valleys occupy an area of about 30 x 80 km2, and the average total number of inhabitants for the period 1877-1970 was 58,621. Information about a sample of 23,744 weddings celebrated between 1875 and 1974 was obtained from 48 village parish registers. The mean inbreeding level up to second cousins for the whole area was 0.0012. A high percentage of inbreeding variation (83%) can be explained by each village's census size, resulting in a different interslope consanguinity pattern consisting of higher inbreeding levels in most northern localities in the Gredos mountains. This north-south geographic trend is consistent with results on blood polymorphisms from the same area (Mesa et al. 1994).

Blood group polymorphisms and geography in the Sierra de Gredos, Spain

The present research is designed to contribute to our knowledge of the influence of geography on the genetic population structure in the Sierra de Gredos (central Spain). This mountain range separates two distinct areas: the Tormes-Alberche valley in the north and the Tiétar valley in the south. Unrelated blood donors (226), whose 4 grandparents were born in the study area, were tested for blood group markers (A1A2BO, RH, MNSs, Kell, P, and Lewis). R matrix analysis in relation to other Spanish populations agrees reasonably well with the cluster analysis of the Prevosti distance matrix using the UPGMA algorithm. Comparisons suggest a certain degree of genetic variation between the populations of these two valleys. The Sierra de Gredos can thus be considered a biological barrier limiting the gene flow between the valleys.

Heritabilities of morphological and body composition characteristics in a Spanish population

Different estimates of heritability are presented for a set of anthropometric characteristics taken in 844 individuals from 261 families living in the Madrid city area (Spain). The data include measurements of 10 craniofacial, 11 body skeletal (4 lengths and 7 breadths), and 13 fat-related characteristics (weight, 3 circumferences, 6 skinfold thicknesses, body mass index and arm fat and arm muscle areas). The estimates computed from parent and offspring data show a clear defined pattern (higher heritabilities for longitudinal traits, followed by breadths, circumferences, and skinfolds, respectively). Heritabilities estimated from sib-sib correlation do not show such pattern and are generally higher than those assessed through parent-offspring data, mainly for fat related traits, which is attributed to common environment effects.

Serum protein polymorphisms (HP, TF-, GC- and PI subtypes) in two mountain communities of Sierra de Gredos (central Spain)

The genetic variation of four highly polymorphic serum proteins, haptoglobin (HP), transferrin (TF), group-specific component (GC) and alpha-1-antitrypsin (PI) was examined in two representative samples of the autochthonous populations living on either slope of Sierra de Gredos in central Spain. The genetic markers studied do not provide any evidence that the mountain chain has contributed to the maintenance of a genetic differentiation between the two populations. The allele frequency distributions in these Gredos samples are discussed in relation to the variability of these markers in the Iberian Peninsula populations.

Assortative mating in a Spanish population: effects of social factors and cohabitation time

Assortative mating for 22 anthropometric and body composition characteristics and social indicators was studied in a Spanish sample of 114 married couples. Significant spousal similarity was found for occupation, educational level and number of siblings. Sex-age adjusted spouse correlations were significant for stature, ileospinal height, total arm length, and biacromial breadth. Spouse correlations were not altered after allowance for socioeconomic effects. When couples were grouped according to marriage duration, differences in mate correlations for fatness were detected, suggesting a cohabitational effect on spouse resemblance.