First experience with a supercharged pedicled jejunal interposition for esophageal replacement after caustic ingestion in a middle-income Latin American country.

Caustic or corrosive substance ingestion that results in severe esophageal and gastric lacerations frequently requires surgical management. The most common sequelae after an upper gastrointestinal tract caustic injury include non-responding luminal strictures, which are subject to esophageal replacement. Late corrective surgery may include esophagectomy with gastric pull-up and jejunal or colonic interpositions. Although long-segment esophageal reconstruction with jejunum is technically feasible and has demonstrated good outcomes, the complexity of the surgery has precluded the widespread use of this procedure in low- and middle-income countries. This document summarizes the most relevant aspects of caustic ingestion surgical management and describes the first Latin American experience in the reconstruction of an esophageal-gastric caustic injury using a pedicled jejunal interposition, as a viable and functional option in mid- and lower-income countries with well-established Thoracic Surgery departments and microsurgery access.

Perspectives of TRPV1 Function on the Neurogenesis and Neural Plasticity.

The development of new strategies to renew and repair neuronal networks using neural plasticity induced by stem cell graft could enable new therapies to cure diseases that were considered lethal until now. In adequate microenvironment a neuronal progenitor must receive molecular signal of a specific cellular context to determine fate, differentiation, and location. TRPV1, a nonselective calcium channel, is expressed in neurogenic regions of the brain like the subgranular zone of the hippocampal dentate gyrus and the telencephalic subventricular zone, being valuable for neural differentiation and neural plasticity. Current data show that TRPV1 is involved in several neuronal functions as cytoskeleton dynamics, cell migration, survival, and regeneration of injured neurons, incorporating several stimuli in neurogenesis and network integration. The function of TRPV1 in the brain is under intensive investigation, due to multiple places where it has been detected and its sensitivity for different chemical and physical agonists, and a new role of TRPV1 in brain function is now emerging as a molecular tool for survival and control of neural stem cells.

Molecular variability of the 16p13.3 region in Amerindians and its anthropological significance.

A total of 1558 base pairs in the 16p13.3 region were investigated in 98 individuals of Mongolian, Northern Arctic and Amerindian affiliation, and the results compared with those obtained in a previous worldwide study of the same genomic region. Fifty-five polymorphic sites could be classified into thirty-five haplotypes from the total data. A median joining network based on the haplotypes revealed two distinct clusters: one with low diversity, with haplotypes found in all five geographic-ethnic categories; while the other, with the most divergent haplotypes, was composed mainly of Africans and a few Amerindians. Almost all neutrality parameters yielded significantly negative values. Demographic simulations with the exclusively Amerindian dataset rejected all scenarios, including a bottleneck beginning more than 12,000 years ago. The demographic scenarios tested considering population growth were similar among the Amerindian and worldwide or Eurasian data sets. The results suggest that Amerindians are a representative sample of Eurasian populations, preserving the signal of demographic growth from the out of Africa exodus and, together with data from uniparental markers, support a scenario of a bottleneck of moderate intensity during the peopling of the New World.

Intra- and intercontinental molecular variability of an Alu insertion in the 3' untranslated region of the LDLR gene.

One-hundred three individuals from two Mongolian, two Siberian, and ten native American populations were studied in relation to a 340-bp sequence from an Alu insertion located in the 3' untranslated region of the LDLR gene. Seven haplotypes have been determined, and haplotype B1 was the most common, accounting for about half the sequences found. In general, diversity values are quite high, about 2.5 times higher than those found in other autosomal Alu sequences. Almost all (93%) of the variability occurs at the intrapopulation level, but the greatest among-group differentiation (6-8%) was found when we grouped in a single population all Native Americans plus Siberian Eskimos and Chukchi and compared them with Mongolians. This result is compatible with earlier mtDNA and Y-chromosome suggestions of a single origin for the first colonizers of the American continent. With this nuclear locus it was not possible to broadly distinguish between Central and South American natives. No evidence of selection or marked demographic changes was obtained with these data.

Gene admixture in the Costa Rican population.

The general population of Costa Rica has sometimes been considered to be the product of an amalgamation of groups of diverse origin. To determine the magnitude of accumulated admixture since Spanish colonization, 11 classic genetic markers were analyzed in a total of 2196 individuals originating from five distinct regions of the country. A maximum likelihood approach was used. The proportions of genes of European, Amerindian and African ancestry were found to be 61%, 30% and 9% of the total population, respectively. Variation was observed at a regional level, with an increased European influence in the North (66%) and Central (65%) regions. Meanwhile an increase in Amerindian ancestry was found in the South (38%), and a higher incidence in the contribution of African genes was detected in the coastal regions (13% in the Atlantic and 14% in the North Pacific). A principal component (PC) analysis showed that 76% of the existing variability can be explained by the first two PCs, which is in agreement with the variations observed in the admixture process by geographic area. It has been concluded that the Costa Rican population is truly trihybrid, similar to populations in other Latin American countries; however, it differs from them fundamentally by the proportion of gene flow from ancestral populations.

Blood group, red cell, and serum protein variation in the Cabecar and Huetar, two Chibchan Amerindian tribes of Costa Rica.

Genetic variation, using blood groups and red cell and serum proteins, was surveyed in the Cabecar of Chirripo and the Huetar of Quitirrisi, Costa Rica. Thirty-nine loci were screened in a sample of 91 Cabecars and 40 loci in 45 Huetars. Twenty-seven loci were monomorphic in the Cabecar and 30 in the Huetar. The proportions of polymorphic loci (P), out of 34 studied by electrophoresis, were 0.235 and 0.177, respectively. Estimated gene diversities (H) of the polymorphic loci were 0.050 in the Cabecar and 0.053 in the Huetar. Two polymorphisms, reported until now in Costa Rican and Panamanian Chibchan groups only, occurred at very high frequencies: TF*DGUA = 0.357 in the Cabecar, the highest frequency ever reported, and 0.033 in the Huetar; and PEPA*F, which reached 0.26 in the Cabecar and 0.29 in the Huetar. Nei's genetic distances and trees (two methods) were used to compare them to seven other Chibchan tribes of Costa Rica. The results placed both the Cabecar of Chirripo and the Huetar closer to the Talamancan Tribes (Bribri and Cabecar). This was an unexpected result for the Huetar, since linguistic studies suggested a closer relationship to the Guatuso. GST, DST, RST, and Dm for three Cabecar subpopulations (Atlantic, Chirripo, and Pacific) doubled their values compared to estimates based on comparison of only two subpopulations: Atlantic and Pacific. Total genetic diversity considering just the three Cabecar subpopulations resembled that obtained including them plus six other Chibchan populations of Costa Rica.

A second locus for an axonal form of autosomal recessive Charcot-Marie-Tooth disease maps to chromosome 19q13.3.

Autosomal recessive Charcot-Marie-Tooth disease (CMT) represents a heterogeneous group of disorders affecting the peripheral nervous system. The axonal form of the disease is designated as "CMT type 2" (CMT2), and one locus (1q21.2-q21.3) has been reported for the autosomal recessive form. Here we report the results of a genomewide search in an inbred Costa Rican family (CR-1) affected with autosomal recessive CMT2. By analyzing three branches of the family we detected linkage to the 19q13.3 region, and subsequent homozygosity mapping defined shared haplotypes between markers D19S902 and D19S907 in a 5.5-cM range. A maximum two-point LOD score of 9.08 was obtained for marker D19S867, at a recombination fraction of.00, which strongly supports linkage to this locus. The epithelial membrane protein 3 gene, encoding a PMP22 homologous protein and located on 19q13.3, was ruled out as being responsible for this form of CMT. The age at onset of chronic symmetric sensory-motor polyneuropathy was 28-42 years (mean 33.8 years); the electrophysiological data clearly reflect an axonal degenerative process. The phenotype and locus are different from those of demyelinating CMT4F, recently mapped to 19q13.1-13.3; hence, the disease affecting the Costa Rican family constitutes an axonal, autosomal recessive CMT subtype (ARCMT2B).

[Analysis of various classical genetic markers in the Costa Rica population]. / Análisis de varios marcadores genéticos clásicos en la población de Costa Rica.

A study of several loci blood groups (ABO, Diego, Duffy, Kell, Kidd, Lewis, Lutheran, MNSs, P, Rhesus and Secretor), and Hp serum protein was carried out on a sample of 2,196 unrelated Costa Rican individuals of both sexes. Data was classified and analyzed according to geographic regions. Gene frequencies and the goodness of fit to Hardy-Weinberg equilibrium were estimated by the maximum likelihood method. A geographic structuring was observed in the Costa Rican population. All the regions of Costa Rica show higher heterozigosity values than the ones observed in the indigenous Costa Rican groups, but similar or slightly higher than the ones observed in the Spanish populations. The genetic distance analysis evidenced that the regions of Costa Rica group close to each other in intermediate positions between the Amerindians and the Spanish, fact that is coherent with the statement that attributes a intermediate origin to the general population of Costa Rica. The data contradicts the idea that the Central region has a radically different population than the rest of the country. The outcome of these markers revealed poor values of exclusion probability in forensic and paternity cases, which confirms the importance of their replacement for DNA markers in the outlines of human identification of judicial investigation systems. These results are similar to other studies made in Latin American populations.

Tendencias actuales en recursos humanos / Current Trends in Human Resources

Este artículo está basado en dos publicaciones aparecidas en lengua inglesa que tienen como tema principal la evaluación del desempeño y el liderazgo. El artículo comienza planteando aquellos cambios en el mundo de trabajo que inciden en la forma de evaluar el desempeño. Entre estos se señalan: el cambio en la naturaleza de las organizaciones, sus estructuras y la estructura de puesto, vale decir, ahora se está ante organizaciones más planas. Por otra parte, los cambios relacionados con la estructura de puestos es otro aspecto que afecta la evaluación del desempeño: incremento del uso de equipos, de personas trabajando desde la casa, conocimiento tecnológico avanzado. Cada vez más el trabajo se realiza en ambientes en que el jefe no puede observar los comportamientos, por eso la evaluación del desemepeño está pasando del comportamiento a los resultados. Por otra parte las definiciones de desempeño están cambiando e incluyen más que tareas individualmente asignadas y habilidades particulares para el trabajo en equipo. Ante estos cambios se sugiere un cambio en la metodología de evaluar el desempeño, entre los que se propone la utilización de múltiples evaluadores. Los sistemas de evaluación del desempeño deben: estar ligados a las metas estratégicas de la organización, reforzar los cambios organizacionales, reforzar los valores organizacionales, ser un instrumento de comunicación entre las personas, proveer información para el desarrollo, ser parte integral de un sistema de recursos humanos. En la segunda parte del artículo el autor presenta un resumen del libro Viv Shackleton sobre el liderazgo y dice que la tesis central del libro es que los líderes son efectivos cuando están motivados por una preocupación por sus seguidores, cuando sus actuaciones están guiadas por el beneficio de sus seguidores, aún cuando esto le signifique un costo para sí mismo

Dispersion of human Y chromosome haplotypes based on five microsatellites in global populations.

We have analyzed five microsatellite loci from the nonrecombining portion of the human Y chromosome in 15 diverse human populations to evaluate their usefulness in the reconstruction of human evolution and early male migrations. The results show that, in general, most populations have the same set of the most frequent alleles at these loci. Hypothetical ancestral haplotypes, reconstructed on the basis of these alleles and their close derivatives, are shared by multiple populations across racial and geographical boundaries. A network of the observed haplotypes is characterized by a lack of clustering of geographically proximal populations. In spite of this, few distinct clusters of closely related populations emerged in the network, which are associated with population-specific alleles. A tree based on allele frequencies also shows similar results. Lack of haplotypic structure associated with the presumed ancestral haplotypes consisting of individuals from almost all populations indicate a recent common ancestry and/or extensive male migration during human evolutionary history. The convergent nature of microsatellite mutation confounds population relationships. Optimum resolution of Y chromosome evolution will require the use of additional microsatellite loci and diallelic genetic markers with lower mutation rates.

Microevolution and genetic affinities among six Amerindian tribes of lower Central America: comparative genetic study of serum proteins.

We evaluate the pattern of genetic variation among native Mesoamerican Amerindians by the construction of a gene frequency map that reflects the past action of evolutionary forces. The analysis is based on the theory that genes of modern human populations carry the encoded history even of humans' remote past and their early wanderings around the globe. We examined the serum proteins TF, PI, F13B and AHSG on 491 samples of 6 Mesoamerican Amerindian tribes (Guaymi, Bribri, Cabecar, Teribe, Guatuso, and Huetar) and 2 tribal mixed samples (Teribe x Guaymi and Bribri x Cabecar). We find a distinct genetic pattern in the examined tribes that clearly separates the Mesoamerican Amerindians from other living Amerindian groups. The proteins, TF, PI, and AHSG proved to be especially rich in special genetically fixed variants and polymorphisms, and F13B proved to be a powerful genetic marker to distinguish human groups. Using Nei's distance D and Mahalanobis's D2, we compared the polymorphisms and allele frequencies at the four serum protein loci to discern degrees of similarity between the samples. These data are presented in the dendrograms computed by average linkage cluster analyses and in two kinds of unrooted phylogenetic trees, neighbor-joining trees and split decompositions. Estimations are made on Hardy-Weinberg equilibrium and on genetic diversity and average heterozygosity index.

Phenylketonuria in Costa Rica: preliminary spectrum of PAH mutations and their associations with highly polymorphic haplotypes.

A preliminary evaluation of the molecular basis of phenylketonuria (PKU) in Costa Rica was made by performing mutational analyses in the six PKU families identified to date. These studies revealed the presence of the previously reported European mutations IVS1nt5, L48S, E221G and IVS12ntl as well as the novel mutation IVS7nt3. The combined use of the STR, VNTR and XmnI polymorphic systems for the PAH gene resulted in a discriminant distribution of haplotypes among normal and mutant chromosomes and suggests its potential usefulness for future diagnostic applications in Costa Rican PKU kindreds. This is the first report of a genetic analysis in a Central American PKU population.

Distribution and evolution of CTG repeats at the myotonin protein kinase gene in human populations.

We have analyzed the CTG repeat length and the neighboring Alu insertion/deletion (+/-) polymorphism in DNA samples from 16 ethnically and geographically diverse human populations to understand the evolutionary dynamics of the myotonic dystrophy-associated CTG repeat. Our results show that the CTG repeat length is variable in human populations. Although the (CTG)5 repeat is the most common allele in the majority of populations, this allele is absent among Costa Ricans and New Guinea highlanders. We have detected a (CTG)4 repeat allele, the smallest CTG known allele, in an American Samoan individual. (CTG) > or = 19 alleles are the most frequent in Europeans followed by the populations of Asian origin and are absent or rare in Africans. To understand the evolution of CTG repeats, we have used haplotype data from the CTG repeat and Alu(+/-) locus. Our results are consistent with previous studies, which show that among individuals of Caucasian and Japanese origin, the association of the Alu(+) allele with CTG repeats of 5 and > or = 19 is complete, whereas the Alu(-) allele is associated with (CTG)11-16 repeats. However, these associations are not exclusive in non-Caucasian populations. Most significantly, we have detected the (CTG)5 repeat allele on an Alu(-) background in several populations including Native Africans. As no (CTG)5 repeat allele on an Alu(-) background was observed thus far, it was proposed that the Alu(-) allele arose on a (CTG)11-13 background. Our data now suggest that the most parsimonious evolutionary model is (1) (CTG)5-Alu(+) is the ancestral haplotype; (2) (CTG)5-Alu(-) arose from a (CTG)5-Alu(+) chromosome later in evolution; and (3) expansion of CTG alleles occurred from (CTG)5 alleles on both Alu(+) and Alu(-) backgrounds.

El consumo de alcohol y otras drogas en el Ministerio de Salud de Costa Rica / Alcohol consumption and another drugs in the Ministerio de Salud of Costa Rica

La temática del consumo de drogas y el medio ambiente laboral, tiene una importancia creciente, en virtud de que es en los trabajadores en quienes se encuentran algunas de las mayores prevalencias de consumo. Información nacional e internacional así lo confirma. Con el objetivo de explorar algunos aspectos del fenómeno en el Ministerio de Salud de Costa Rica, se desarrolló un trabajo colaborativo entre dicha entidad y el Instituto sobre Alcoholismo y Farmacodependencia, con el especial interés de definir, a corto plazo, acciones de tipo preventivo. Tal cometido fue posible mediante la selección de noventa y un informantes claves, que aportaron información acerca de mil setecientos setenta y un funcionarios, cifra que representa al 30 por ciento de la población institucional...

Lack of a BglII site at the 5' region of the PGK 1 locus: a new variant discovered in two Chibchan Amerindian groups from Costa Rica.

A new 3.8-kb allele at the 5' region of the PGK 1 locus detected by the probe pSPT/PGK is reported. This variant was discovered in the Cabecar and Guaymi, two Chibchan Amerindian groups of Costa Rica. So far, a polymorphism that consists of an EcoRI/BglI (1.3-kb) variable site within an EcoRI/BglII (1.7-kb) fragment when DNA is simultaneously digested with EcoRI, BglI and BglII is known to occur in black and Caucasian populations. These two alleles were also found in the Amerindians tested. The newly described band is due to the lack of the BglII site situated 1.7 kb downstream from the EcoRI site and to the cleavage of another BglII site 2.1 kb downstream from the lacking one. This variant might be restricted to some Amerindian groups and perhaps also to Asiatic populations. Thus, it could be a useful marker in evolutive studies and for forensic applications. Moreover, the presence of a third allele in populations with Amerindian ancestry can increase the heterozygosity of the region disclosed by the pSPT/PGK probe, thus improving its application in issues dealing with X-chromosome activation ratios in females.

mtDNA variation in the Chibcha Amerindian Huetar from Costa Rica.

The genetic variation in a Chibcha-speaking Amerindian tribe from lower Central America, the Huetar, was analyzed using nucleotide sequences of the hypervariable segments of the mitochondrial DNA (mtDNA) control region, the frequencies of 10 Amerindian-specific mtDNA haplotypes, and the regional distribution of private protein polymorphisms. The sequencing of 713 base pairs (bp) in the control regions of 27 individuals revealed 11 distinct lineages. These were defined by 24 variable sites and a 6-bp deletion between nucleotide pairs (np) 106 and 111. The 6-bp deletion is a new mtDNA marker that will be valuable for Amerindian taxonomic research. Control region sequences and mtDNA haplotype analyses reveal that Huetar mtDNAs are distributed in "Amerindian clusters" A, B, and D. A maximum-likelihood phylogenetic tree suggests a single origin for the 6-bp Huetar deletion in the sample. mtDNA haplotype analysis and the presence of previously characterized private protein variants (PEPA*F, TF*DCHI, and the absence of DI*A) show that the Huetar harbor polymorphisms of considerable antiquity, suggesting an early divergence from the regional founder gene pool for this population. The data also reflect a drastic constriction in population size, an evolutionary event with a proposed central effect on Huetar genetic structure.

Direct screening of a mitochondrial DNA deletion valuable for Amerindian evolutionary research.

A rapid, simple restriction isotyping method is described for the direct screening of a previously characterized Amerindian mitochondrial DNA (mtDNA) marker consisting of a 6-bp "Huetar" deletion. In a sample of 31 maternally non-related Chibchan Amerindian Bribri from Costa Rica, this deletion was present in 74%, arguing for the usefulness of this private polymorphism for Amerindian taxonomic research.