Genomics of the origin and evolution of Citrus.

The genus Citrus, comprising some of the most widely cultivated fruit crops worldwide, includes an uncertain number of species. Here we describe ten natural citrus species, using genomic, phylogenetic and biogeographic analyses of 60 accessions representing diverse citrus germ plasms, and propose that citrus diversified during the late Miocene epoch through a rapid southeast Asian radiation that correlates with a marked weakening of the monsoons. A second radiation enabled by migration across the Wallace line gave rise to the Australian limes in the early Pliocene epoch. Further identification and analyses of hybrids and admixed genomes provides insights into the genealogy of major commercial cultivars of citrus. Among mandarins and sweet orange, we find an extensive network of relatedness that illuminates the domestication of these groups. Widespread pummelo admixture among these mandarins and its correlation with fruit size and acidity suggests a plausible role of pummelo introgression in the selection of palatable mandarins. This work provides a new evolutionary framework for the genus Citrus.

Comparative transcriptomics of wild and commercial Citrus during early ripening reveals how domestication shaped fruit gene expression.

BACKGROUND: Interspecific hybridizations and admixtures were key in Citrus domestication, but very little is known about their impact at the transcriptomic level. To determine the effects of genome introgressions on gene expression, the transcriptomes of the pulp and flavedo of three pure species (citron, pure mandarin and pummelo) and four derived domesticated genetic admixtures (sour orange, sweet orange, lemon and domesticated mandarin) have been analyzed at color break. RESULTS: Many genes involved in relevant physiological processes for domestication, such sugar/acid metabolism and carotenoid/flavonoid synthesis, were differentially expressed among samples. In the low-sugar, highly acidic species lemon and citron, many genes involved in sugar metabolism, the TCA cycle and GABA shunt displayed a reduced expression, while the P-type ATPase CitPH5 and most subunits of the vacuolar ATPase were overexpressed. The red-colored species and admixtures were generally characterized by the overexpression in the flavedo of specific pivotal genes involved in the carotenoid biosynthesis, including phytoene synthase, ζ-carotene desaturase, ß-lycopene cyclase and CCD4b, a carotenoid cleavage dioxygenase. The expression patterns of many genes involved in flavonoid modifications, especially the flavonoid and phenylpropanoid O-methyltransferases showed extreme diversity. However, the most noticeable differential expression was shown by a chalcone synthase gene, which catalyzes a key step in the biosynthesis of flavonoids. This chalcone synthase was exclusively expressed in mandarins and their admixed species, which only expressed the mandarin allele. In addition, comparisons between wild and domesticated mandarins revealed that the major differences between their transcriptomes concentrate in the admixed regions. CONCLUSION: In this work we present a first study providing broad evidence that the genome introgressions that took place during citrus domestication largely shaped gene expression in their fruits.

Regulation of carotenoid and chlorophyll pools in hesperidia, anatomically unique fruits found only in Citrus.

Domesticated citrus varieties are woody perennials and interspecific hybrid crops of global economic and nutritional importance. The citrus fruit "hesperidium" is a unique morphological innovation not found in any other plant lineage. Efforts to improve the nutritional quality of the fruit are predicated on understanding the underlying regulatory mechanisms responsible for fruit development, including temporal control of chlorophyll degradation and carotenoid biosynthesis. Here, we investigated the molecular basis of the navel orange (Citrus sinensis) brown flavedo mutation, which conditions flavedo that is brown instead of orange. To overcome the limitations of using traditional genetic approaches in citrus and other woody perennials, we developed a strategy to elucidate the underlying genetic lesion. We used a multi-omics approach to collect data from several genetic sources and plant chimeras to successfully decipher this mutation. The multi-omics strategy applied here will be valuable in driving future gene discovery efforts in citrus as well as in other woody perennial plants. The comparison of transcriptomic and genomic data from multiple genotypes and plant sectors revealed an underlying lesion in the gene encoding STAY-GREEN (SGR) protein, which simultaneously regulates carotenoid biosynthesis and chlorophyll degradation. However, unlike SGR of other plant species, we found that the carotenoid and chlorophyll regulatory activities could be uncoupled in the case of certain SGR alleles in citrus and thus we propose a model for the molecular mechanism underlying the brown flavedo phenotype. The economic and nutritional value of citrus makes these findings of wide interest. The strategy implemented, and the results obtained, constitute an advance for agro-industry by driving opportunities for citrus crop improvement.

Chilean reference of length at birth.

BACKGROUND: To generate a reference of length at birth (LB) according to sex and gestational age (GA) of the Chilean population. METHODS: This cross-sectional observational study used public pooled Chilean newborn (NB) population data registered by the Civil Registry and Identification Service in Chile from 2000 to 2016. Multiple births, entries without information for LB, GA, and sex, and birth lengths <-4SD and > 4SD, were excluded. After applying the selection and randomization criteria, the final sample was made up of 5 010 963 NB (2 560 310 boys; 2 450 653 girls). Length at birth centiles by sex and GA (24-42 weeks) were calculated using the GAMLSS method and then compared with the INTERGROWTH-21st standard. RESULTS: Girls had a lower LB than boys. For most GA and in both sexes, the absolute and percentage differences of percentiles as compared with INTERGROWTH-21st were lower than 1 cm and 1%, respectively. CONCLUSIONS: We present a reference for LB by sex and GA in the Chilean population, developed following updated methodological criteria for neonatal anthropometry, which is acceptably consistent with the INTERGROWTH-21st standard. The reference we propose may be used in clinical and epidemiological studies to identify either Chilean individuals or populations, respectively, at higher risk of perinatal and infant adverse events related to LB.

Waist circumference percentiles for Hispanic-American children and comparison with other international references.

INTRODUCTION: Waist circumference (WC) constitutes an indirect measurement of central obesity in children and adolescents. OBJECTIVE: To provide percentiles of WC for Hispanic-American children and adolescents, and compare them with other international references. MATERIALS AND METHODS: The sample comprised 13 289 healthy children between 6 and 18 years coming from public schools of middle and low socioeconomic levels in different parts of Argentina, Cuba, Spain, Mexico, and Venezuela. The LMS method to calculate WC percentiles was applied. Sex and age differences were assessed using Student's t test and ANOVA (SPSS v.21.0). Comparisons were established with references from the United States, Colombia, India, China, Australia, Kuwait, Germany, Tunisia, Greece, and Portugal. RESULTS: WC increases with age in both sexes. Boys show higher WC in P3, P50, and P97. Comparison of 50th and 90th percentiles among populations from diverse sociocultural and geographical contexts shows high variability, not all justified by the measurement method. DISCUSSION AND CONCLUSIONS: Specific WC percentiles for sex and age, and P90 cut-off points are provided; these values are potentially useful to assess central obesity in Hispanic-American adolescent children.

Breast cancer risk and genetic ancestry: a case-control study in Uruguay.

BACKGROUND: Uruguay exhibits one of the highest rates of breast cancer in Latin America, similar to those of developed nations, the reasons for which are not completely understood. In this study we investigated the effect that ancestral background has on breast cancer susceptibility among Uruguayan women. METHODS: We carried out a case-control study of 328 (164 cases, 164 controls) women enrolled in public hospitals and private clinics across the country. We estimated ancestral proportions using a panel of nuclear and mitochondrial ancestry informative markers (AIMs) and tested their association with breast cancer risk. RESULTS: Nuclear individual ancestry in cases was (mean ± SD) 9.8 ± 7.6% African, 13.2 ± 10.2% Native American and 77.1 ± 13.1% European, and in controls 9.1 ± 7.5% African, 14.7 ± 11.2% Native American and 76.2 ± 14.2% European. There was no evidence of a difference in nuclear or mitochondrial ancestry between cases and controls. However, European mitochondrial haplogroup H was associated with breast cancer (OR = 2.0; 95% CI 1.1, 3.5). CONCLUSIONS: We have not found evidence that overall genetic ancestry differs between breast cancer patients and controls in Uruguay but we detected an association of the disease with a European mitochondrial lineage, which warrants further investigation.

Geographical altitude, size, mass and body surface area in children (1-4 years) in the Province of Jujuy (Argentina).

BACKGROUND: Highland child populations show low growth rates. AIM: To evaluate the variation of size, mass and body surface area of Jujenean infants (1-4 years) as a function of geographic altitude. SUBJECTS AND METHODS: Nutritional status of 8059 healthy infants was determined based on weight and height data; body mass index, ponderal index, body surface area, body surface area/mass and ectomorphy were calculated. Variables were standardized with a provincial mean and WHO references. Data were grouped by age, sex and geographic altitude: Highlands (≥2500 masl) and Lowlands (<2500 masl). Chi-square, correlation and t-tests were applied. RESULTS: Highlands infants had higher prevalence of stunting, reduced height, weight, body surface area and ectomorphy; also higher body mass index, ponderal index and body surface area/mass. The population average z-score for height, weight and body surface area was positive in Lowlands and negative in Highlands. The opposite happened with body mass index, ponderal index and body surface area/mass. In Highlands and Lowlands the average z-score reference was negative for weight and height and positive for body mass index. Correlations between indices were high and significant, higher in Highlands. CONCLUSION: Jujenean children differ in size, mass and body surface area based on the geographical altitude and adverse nutritional and socioeconomic factors.

Single-nucleotide mosaicism in citrus: Estimations of somatic mutation rates and total number of variants.

Most of the hundreds of citrus varieties are derived from spontaneous mutations. We characterized the dynamics of single-nucleotide mosaicism in a 36-yr-old clementine (Citrus ×clementina hort. ex Tanaka) tree, a commercial citrus whose vegetative behavior is known in detail. Whole-genome sequencing identified 73 reliable somatic mutations, 48% of which were transitions from G/C to A/T, suggesting ultraviolet (UV) exposure as mutagen. The mutations accumulated in sectorized areas of the tree in a nested hierarchy determined by the branching pattern, although some variants detected in the basal parts were also found in the new growth and were fixed in some branches and leaves of much younger age. The estimate of mutation rates in our tree was 4.4 × 10-10 bp-1 yr-1 , a rate in the range reported in other perennials. Assuming a perfect configuration and taking advantage of previous counts on the number of total leaves of typical clementine trees, these mutation determinations allowed to estimate for the first time the total number of variants present in a standard adult tree (1,500-5,000) and the somatic mutations generated in a typical leaf flush (0.92-1.19). From an evolutionary standpoint, the sectoral distribution of somatic mutations and the habit of periodic foliar renewal of long-lived plants appear to increase genetic heterogeneity and, therefore, the adaptive role of somatic mutations reducing the mutational load and providing fitness benefits.

Transcriptome analysis of the pulp of citrus fruitlets suggests that domestication enhanced growth processes and reduced chemical defenses increasing palatability.

To identify key traits brought about by citrus domestication, we have analyzed the transcriptomes of the pulp of developing fruitlets of inedible wild Ichang papeda (Citrus ichangensis), acidic Sun Chu Sha Kat mandarin (C. reticulata) and three palatable segregants of a cross between commercial Clementine (C. x clementina) and W. Murcott (C. x reticulata) mandarins, two pummelo/mandarin admixtures of worldwide distribution. RNA-seq comparison between the wild citrus and the ancestral sour mandarin identified 7267 differentially expressed genes, out of which 2342 were mapped to 117 KEGG pathways. From the remaining genes, a set of 2832 genes was functionally annotated and grouped into 45 user-defined categories. The data suggest that domestication promoted fundamental growth processes to the detriment of the production of chemical defenses, namely, alkaloids, terpenoids, phenylpropanoids, flavonoids, glucosinolates and cyanogenic glucosides. In the papeda, the generation of energy to support a more active secondary metabolism appears to be dependent upon upregulation of glycolysis, fatty acid degradation, Calvin cycle, oxidative phosphorylation, and ATP-citrate lyase and GABA pathways. In the acidic mandarin, downregulation of cytosolic citrate degradation was concomitant with vacuolar citrate accumulation. These changes affected nitrogen and carbon allocation in both species leading to major differences in organoleptic properties since the reduction of unpleasant secondary metabolites increases palatability while acidity reduces acceptability. The comparison between the segregants and the acidic mandarin identified 357 transcripts characterized by the occurrence in the three segregants of additional downregulation of secondary metabolites and basic structural cell wall components. The segregants also showed upregulation of genes involved in the synthesis of methyl anthranilate and furaneol, key substances of pleasant fruity aroma and flavor, and of sugar transporters relevant for sugar accumulation. Transcriptome and qPCR analysis in developing and ripe fruit of a set of genes previously associated with citric acid accumulation, demonstrated that lower acidity is linked to downregulation of these regulatory genes in the segregants. The results suggest that the transition of inedible papeda to sour mandarin implicated drastic gene expression reprograming of pivotal pathways of the primary and secondary metabolism, while palatable mandarins evolved through progressive refining of palatability properties, especially acidity.

Shaping the biology of citrus: I. Genomic determinants of evolution.

We performed genomic analyses on wild species of the genus Citrus to identify major determinants of evolution. The most notable effect occurred on the pathogen-defense genes, as observed in many other plant genera. The gene space was also characterized by changes in gene families intimately related to relevant biochemical properties of citrus fruit, such as pectin modifying enzymes, HDR (4-hydroxy-3-methylbut-2-enyl diphosphate reductase) genes, and O-methyltransferases. Citrus fruits are highly abundant on pectins and secondary metabolites such as terpenoids and flavonoids, the targets of these families. Other gene types under positive selection, expanded through tandem duplications and retained as triplets from whole genome duplications, codified for purple acid phosphatases and MATE-efflux proteins. Although speciation has not been especially rapid in the genus, analyses of selective pressure at the codon level revealed that the extant species evolved from the ancestral citrus radiation show signatures of pervasive adaptive evolution and is therefore potentially responsible for the vast phenotypic differences observed among current species.

Shaping the biology of citrus: II. Genomic determinants of domestication.

We performed genomic analyses on species and varieties of the genus Citrus to identify several determinants of domestication, based on the pattern of pummelo [Citrus maxima (Burr. f) Merr] and mandarin (Citrus reticulata Blanco) admixture into the ancestral genome, as well as population genetic tests at smaller scales. Domestication impacted gene families regulating pivotal components of citrus flavor (such as acidity) because in edible mandarin varieties, chromosome areas with negative Tajimas values were enriched with genes associated with the regulation of citric acid. Detection of sweeps in edible mandarins that diverged from wild relatives indicated that domestication reduced chemical defenses involving cyanogenesis and alkaloid synthesis, thus increasing palatability. Also, a cluster of SAUR genes in domesticated mandarins derived from the pummelo genome appears to contain candidate genes controlling fruit size. Similarly, conserved stretches of pure mandarin areas were likely important as well for domestication, as, for example, a fragment in chromosome 1 that is involved in the apomictic reproduction of most edible mandarins. Interestingly, our results also support the hypothesis that various genes subject to selective pressure during evolution or derived from whole genome duplication events later became potential targets of domestication.

Geographic altitude and prevalence of underweight, stunting and wasting in newborns with the INTERGROWTH-21st standard.

OBJECTIVE: To assess the prevalence and risks of underweight, stunting and wasting by gestational age in newborns of the Jujuy Province, Argentina at different altitude levels. METHODS: Live newborns (n=48,656) born from 2009-2014 in public facilities with a gestational age between 24+0 to 42+6 weeks. Phenotypes of underweight (2.000m.a.s.l. Maternal age, body mass index >35kg/m2, hypertension, congenital malformations, and prematurity were more strongly associated with underweight rather than stunting or wasting at ≥2.000m.a.s.l. CONCLUSIONS: Underweight, stunting, and wasting risks were higher at a higher altitude, and were associated with recognized maternal and fetal conditions. The use of those three phenotypes will help prioritize preventive interventions and focus the management of fetal undernutrition.

Reprogramming of Retrotransposon Activity during Speciation of the Genus Citrus.

Speciation of the genus Citrus from a common ancestor has recently been established to begin ∼8 Ma during the late Miocene, a period of major climatic alterations. Here, we report the changes in activity of Citrus LTR retrotransposons during the process of diversification that gave rise to the current Citrus species. To reach this goal, we analyzed four pure species that diverged early during Citrus speciation, three recent admixtures derived from those species and an outgroup of the Citrus clade. More than 30,000 retrotransposons were grouped in ten linages. Estimations of LTR insertion times revealed that retrotransposon activity followed a species-specific pattern of change that could be ascribed to one of three different models. In some genomes, the expected pattern of gradual transposon accumulation was suddenly arrested during the radiation of the ancestor that gave birth to the current Citrus species. The individualized analyses of retrotransposon lineages showed that in each and every species studied, not all lineages follow the general pattern of the species itself. For instance, in most of the genomes, the retrotransposon activity of elements from the SIRE lineage reached its highest level just before Citrus speciation, while for Retrofit elements, it has been steadily growing. Based on these observations, we propose that Citrus retrotransposons may respond to stressful conditions driving speciation as a part of the genetic response involved in adaptation. This proposal implies that the evolving conditions of each species interact with the internal regulatory mechanisms of the genome controlling the proliferation of mobile elements.

Reference percentiles for mid-upper arm circumference, upper arm muscle and fat areas in the Argentine child and adolescent population (4-14 years old). / Percentilos de referencia de la circunferencia y de las áreas muscular y grasa del brazo para la población infantojuvenil argentina (4-14 años).

INTRODUCTION: Mid-upper arm circumference (MUAC) is widely recognized as an adequate indicator of nutritional status. OBJECTIVE: To estimate the reference percentiles for MUAC, upper arm muscle area (UAMA), and upper arm fat area (UAFA) in the Argentine child and adolescent population using the LMS method (lambda, mu, sigma). MATERIALS AND METHODS: The sample was made up of schoolchildren aged 4.0-13.9 years living in Jujuy, Catamarca, Misiones, Buenos Aires, Mendoza, and Chubut. MUAC and tricipital skinfold anthropometric measurements were obtained between 2003 and 2008 as per standardized protocols. UAMA and UAFA were calculated, and percentiles by age and sex were estimated and compared using an analysis of variance. RESULTS: A total of 22 736 schoolchildren (11 397 boys and 11 339 girls) were included. The 50th percentile was higher for the MUAC and UAFA among girls and for the UAMA among boys. The MUAC curves showed sharper increases as of 7 years old in all percentiles among both boys and girls. A similar pattern was observed for the UAMA, with higher values among boys. Lastly, the UAFA showed a constant increase among girls and a stabilization among boys as of 11 years old. Differences for age were observed. CONCLUSIONS: The tabulated and plotted percentiles and the MUAC, UAMA, and UAFA may be used as local references for epidemiological and anthropological studies.

Introducción: La circunferencia del brazo (CB) se reconoce como buen indicador del estado nutricional. Objetivo: Estimar los percentilos de referencia para la CB y las áreas muscular (AM) y grasa (AG) del brazo en la población infantojuvenil argentina mediante el empleo del método LMS (lambda, mu, sigma, en inglés). Materiales y métodos: La muestra estuvo constituida por escolares de 4,0 a 13,9 años residentes en Jujuy, Catamarca, Misiones, Buenos Aires, Mendoza y Chubut. Las mediciones antropométricas de la CB y del pliegue tricipital se realizaron entre 2003 y 2008 siguiendo protocolos estandarizados. Se estimaron las AM, AG, se calcularon los percentilos por edad y sexo, y se compararon mediante el análisis de la varianza. Resultados: Se incluyeron 22 736 escolares (11 397 varones y 11 339 mujeres). Los valores correspondientes al percentilo 50 fueron superiores, en las mujeres, para CB y AG, y, en los varones, para AM. Las curvas de CB presentaron incrementos más marcados a partir de los 7 años en todos los percentilos, para ambos sexos. Un patrón similar se observó para AM, con valores superiores en los varones. Por último, el AG mostró aumento constante en las mujeres y estabilización en los varones a partir de los 11 años. Se observaron diferencias para la edad. Conclusiones: Los valores de percentilos, tabulados y graficados, de la CB y de las AM y AG del brazo pueden constituir una referencia local para estudios epidemiológicos y antropológicos.

Comparative study of mid-upper arm circumference, arm muscle area and arm fat area percentiles in Argentinean and US children aged 4-14 years.

INTRODUCTION: Background: mid-upper arm circumference (MUAC), subcutaneous fat and muscle measurements are an alternative method to diagnose overweight and evaluate growth as well as protein and energy reserves. Aim: to compare MUAC, arm muscle area (AMA) and arm fat area (AFA) measurements of Argentinean boys and girls (Sa) with reference curves for US boys and girls (R). Subjects and methods: data from 22,736 school-children aged 4-14 years from six Argentinean provinces were collected. MUAC and triceps skinfold thickness were measured and the derived AMA and AFA measures were calculated. Analyses were performed with GAMLSS using the R software. Differences in mean values of Sa and R were compared in percentiles 3, 50 and 97. Results: mean values of MUAC and AMA in boys and girls were higher in R than in Sa at all ages; conversely, AFA values were lower. Conclusions: our results confirm differences in upper arm anthropometry of Argentinean school-children with respect to the US reference. The higher adipose tissue and lower skeletal muscle mass observed in Argentinean children could be partly associated with the different ethnic origin of both populations. However, differences should be interpreted in the context of an obesogenic environment, which has favored a calorie-protein imbalance.

INTRODUCCIÓN: Antecedentes: la medición de la circunferencia del brazo (MUAC), así como la estimación de la grasa subcutánea y muscular constituyen un método alternativo para diagnosticar el sobrepeso y evaluar el crecimiento y las reservas proteicas y energéticas. Objetivo: comparar las mediciones de MUAC, área muscular (AMA) y área grasa (AFA) del brazo de niños y niñas argentinos (Sa) con curvas de referencia para niños y niñas de Estados Unidos (R). Sujetos y métodos: se recopilaron datos de 22,736 escolares de 4 a 14 años de edad de seis provincias argentinas. Se obtuvieron medidas de MUAC y pliegue subcutáneo tricipital y se calcularon AMA y AFA. Los análisis se realizaron con GAMLSS utilizando el software R. Las diferencias en los valores medios de Sa y R se compararon para los percentiles 3, 50 y 97. Resultados: a todas las edades los valores medios de MUAC y AMA en niños y niñas fueron más altos en R que en Sa; por el contrario, los valores de AFA fueron más bajos. Conclusiones: nuestros resultados confirman la existencia de diferencias en la antropometría mesobraquial de los niños argentinos con respecto a los de la referencia. La mayor cantidad de tejido adiposo y menor de tejido muscular observada en los niños argentinos de ambos sexos puede ser parcialmente asociada con el diferente origen étnico de ambas poblaciones. Sin embargo, las diferencias podrían interpretarse en el contexto de un ambiente obesogénico, el cual habría favorecido el desbalance proteico-calórico.

Translational machinery and protein folding: evidence of conformational variants of the estrogen receptor alpha.

As an approach to understand how translation may affect protein folding, we analyzed structural and functional properties of the human estrogen receptor alpha synthesized by different eukaryotic translation systems. A minimum of three conformations of the receptor were detected using limited proteolysis and a sterol ligand-binding assay. The receptor in vitro translated in rabbit reticulocyte lysate was rapidly degraded by protease, produced major bands of about 34kDa and showed a high affinity for estradiol. In a wheat germ translation system, the receptor was more slowly digested. Two soluble co-existing conformations were evident by different degradation patterns and estradiol binding. Our data show that differences in the translation machinery may result in alternative conformations of the receptor with distinct sterol binding properties. These studies suggest that components of the cellular translation machinery itself might influence the protein folding pathways and the relative abundance of different receptor conformers.

Lethality and histopathological alterations caused by Phoneutria nigriventer spider venom from Argentina: Neutralization of lethality by experimental and therapeutic antivenoms.

Although the spiders of the genus Phoneutria cause envenomation and their presence has been described in several provinces of the north of Argentina, they are not as common as other spiders of sanitary importance. In the present work, we studied the toxicity of samples of venom of Phoneutria spiders from the provinces of Misiones (where severe envenomation and deaths by Phoneutria have been recorded) and Jujuy (where no deaths have been recorded and severe envenomations are not frequent). To this end, we assessed the lethal potency in mice and guinea pigs and the histopathological alterations caused by both venoms, as well as the neutralization by the commonly used therapeutic antivenom produced by the Butantan Institute in Brazil and by an experimental antivenom developed with venom of P. nigriventer from Misiones. There were no differences in the lethality of the venoms of spiders from both regions. Post mortem examination showed that the heart and lungs were the most affected organs, while important pulmonary edema was seen macroscopically. Histological analysis showed edema, atelectasis, emphysema and cardiac lesion in both experimental models. The antivenoms assayed showed good neutralization of the venoms in the two experimental models. Despite the different geographic origins, the venoms showed similar toxicity and both the experimental antivenom and therapeutic antivenmos were able to neutralize the venoms of Argentinean P. nigriventer.

Referencias de índice de masa corporal. Precisión diagnóstica con área grasa braquial en escolares argentinos / Body mass index references. Diagnostic accuracy with the upper-arm fat area in Argentine schoolchildren

El índice de masa corporal (IMC) es una eficaz herramienta para detectar la sobrecarga ponderal en niños y adolescentes, asociado a la adiposidad corporal. Objetivo. Analizar la concordancia, sensibilidad y especificidad de tres referencias internacionales de IMC/edad (OMS, IOTF y CDC) para diagnosticar el exceso ponderal y conocer su precisión diagnóstica para identificar el exceso de adiposidad con relación al área grasa braquial (AGB) en población infanto juvenil de Argentina. Materiales y métodos. Se realizó un estudio multicéntrico, descriptivo-comparativo y transversal entre 2003 y 2008, en 22.658 niños y adolescentes argentinos de 4 a 13 años de edad. A partir del peso, talla, circunferencia del brazo y pliegue tricipital, se calcularon IMC y AGB. Se analizó la concordancia, sensibilidad y especificidad de referencias de IMC/edad (OMS, CDC, IOTF) y la precisión diagnóstica (curvas ROC) para identificar exceso de adiposidad, a partir del AGB, así como el punto de corte óptimo (PCO). Resultados. Las tres referencias tuvieron buena concordancia. La mayor sensibilidad correspondió a OMS y la mayor especificidad a IOTF. El área bajo la curva (ABC) fue mayor en Z-IMC/IOTF en varones y en Z-IMC/OMS en mujeres. Los PCO mostraron discrepancias, siendo mayores con OMS. Conclusión. Las tres referencias muestran similar precisión diagnóstica para detectar alta reserva calórica, con puntos de corte óptimo para las puntuaciones Z-IMC menores a 2 Z scores. Esto resulta relevante para la identificación de exceso de adiposidad en poblaciones, en relación con la implementación de políticas públicas de prevención de enfermedades crónicas no transmisibles(AU)

The body mass index (BMI) is an effective tool to detect weight overload in children and adolescents, associated with body adiposity. Objective. To analyze the concordance, sensitivity and specificity of three international BMI/age references (WHO, IOTF and CDC) to diagnose excess weight and to know their diagnostic accuracy to identify excess adiposity in relation to the brachial fat area (BFA) in Argentine child-youth population. Materials and methods. A multicenter, descriptive- comparative and cross-sectional study was carried out between 2003 and 2008 in 22.658 Argentine children and adolescents between aged 4 to 13 years. From the weight, height, arm circumference and tricipital fold, BMI and BFA were calculated. The concordance, sensitivity, and specificity of BMI / age references (WHO, IOTF, CDC,) were analyzed and the diagnostic precision (ROC curves) to identify excess adiposity, from the BFA, as well as the optimal cut-off point (OCP). Results. The three references had good agreement, the highest sensitivity corresponded to WHO and the highest specificity to IOTF. The area under the curve (AUC) was greater in Z-BMI/IOTF in men and in Z-BMI/WHO in women. The OCPs showed discrepancies, being higher with WHO. Conclusion. The three references show similar diagnostic accuracy to detect high caloric reserve, but with cut-off points for Z-BMI scores less than 2 Z scores. This is relevant for the identification of excess adiposity in populations in relation to the implementation of public policies for the prevention of chronic non-communicable diseases(AU)

[Placental weight percentiles and its relationship with fetal weight according to gestational age in an urban area of Buenos Aires]. / Percentilos del peso de la placenta y su relación con el peso fetal según la edad gestacional en el área urbana de Buenos Aires.

BACKGROUND: The placental weight (PW) and the rates of their relationship with birth weight (BW) (BW / PW, PW / BW) predict perinatal morbidity and mortality and future health outcomes. OBJECTIVES: Estimate percentiles of PW and indices by sex and gestational age (GA) corresponding to 867 live born from Sardá Maternity of Buenos Aires and compare with international references. METHODS: Stillbirth, multiple pregnancy, gestational age <22 and > 42 weeks and PW <100g and > 2500g were excluded. Maternal and fetal characteristics were: age, education, smoking, parity, diabetes, preeclampsia, chorioamnionitis, growth restriction, prematurity and congenital anomalies. Summary statistics and percentiles with the LMS method were calculated. The comparisons were performed using Student t-test, ANOVA and international references. RESULTS: Average maternal age 24 years , education 10.1 years, 24.5% primiparous, 12.6% smokers, 4.9% had diabetes, 8.7% preeclampsia, 7.9% chorioamnionitis and 13.0% fetal growth restriction; 55.3% of newborns were male, 51.6% preterm, 18.9% small for gestational age and 7.1% malformed. On average BW and GA were 2581g and 35.6 weeks, respectively. High positive correlation between GA with PW and BW/PW, and negative with PW/BW was observed (p <0.001); placental weight and indices were higher in males. Percentiles of PW, BW / PW and PW / BW are depicted. Differences with references ranged from 0.46% -13%, 4.91% -12.1% and 5.81% -14% for PW, BW / PW and PW / BW, respectively. CONCLUSIONS: Percentiles generated are applicable in research on the relationship of the placenta with perinatal outcomes and health throughout the life cycle.

Antecedentes: El peso placentario (PP) y los índices de su relación con el peso al nacer (PN) (PN/PP, PP/PN) predicen morbi-mortalidad perinatal y resultados alejados de la salud. Objetivos: Calcular percentilos del PP e índices por sexo y edad gestacional correspondientes a 867 RNV de la Maternidad Sardá de Buenos Aires, Argentina y compararlos con referencias internacionales. Material y métodos: Se excluyeron feto muerto, embarazo múltiple, edad gestacional <22 y >42 semanas y PP<100g y >2500g. Características maternas y fetales: edad, educación, tabaco, paridad, diabetes, preeclampsia, corioamnionitis, restricción del crecimiento, malformación congénita y prematurez. Se calcularon estadísticos de resumen y percentilos con el método LMS. Las comparaciones se realizaron con test t-Student, ANOVA y referencias internacionales. Resultados: Edad materna media 24 años, educación 10.1 años, 24.5% primíparas, 12.6% fumadoras, 4.9% presentaron diabetes, 8.7% preeclampsia, 7.9% corioamnionitis y 13.0% restricción del crecimiento fetal. El 55.3% de los RN fueron varones, 51.6% prematuros, 18.9% PEG y 7.1% malformados. El PN y EG promedio fue de 2581g y 35.6 semanas respectivamente. Elevada correlación positiva de la EG con PP y PN/PP y negativa con PP/PN (p%lt;0.001); el peso de la placenta e índices fueron mayores en varones. Se presentan los percentiles de PP, PN/PP y PP/PN. Las diferencias con las referencias oscilaron de 0.46% -13%, 4.91% -12.1% y 5.81% -14% para el PP, PN/PP y PP/PN respectivamente. Conclusiones: los percentilos generados son aplicables en investigaciones sobre la relación de la placenta con resultados perinatales y la salud durante el ciclo vital.

Composite index of anthropometric failure and geographic altitude in children from Jujuy (1 to 5 years old).

INTRODUCTION: The Composite Index of Anthropometric Failure (CIAF) is made up of typical anthropometric indicators and their combination into seven categories, and proposes an additional measure to study malnutrition as an alternative to the evaluation of stunting, wasting and underweight as separate measures. OBJECTIVE: To assess the CIAF in the child population settled at different altitudinal zones in Jujuy. POPULATION AND METHODS: Weight and height were obtained from healthy 1 to 5 year-old control children, measured at primary healthcare centers (PHCCs) in Jujuy between 2005 and 2007. Nutritional status indicators such as underweight, stunting and wasting were determined as per the World Health Organization 2007 child growth standards. The CIAF and its seven categories were estimated by grouping data by gender, age and altitudinal zone (highlands: >2500 MASL; lowlands: <2500 MASL). The CIAF percentage differences for height, gender and age were verified using a chi-square test. RESULTS: A total of 8059 children were included. The CIAF for highland children (6.1%) doubled that for lowland children (3.4%) (p < 0.05), and underweight prevalence (group Y) was significantly higher in the highlands (p < 0.05). The CIAF value and stunting (group F) increased with age, but such increase was more significant in the highlands. CONCLUSIONS: A significantly higher CIAF was observed in highland children, at the expense of stunting. However, the index of anthropometric failure was not more than 10% at both the highlands and the lowlands, and this accounts for a scarcely significant malnutrition health status in the studied child population of Jujuy.