Tomás D Arias

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Mitochondrial DNA (mtDNA) haplotype diversity was determined for 46 Ngöbé Amerinds sampled widely across their geographic range in western Panamá. The Ngöbé data were compared with mtDNA control region I sequences from two additional Amerind groups located at the northern and southern extremes of Amerind distribution, the Nuu-Chah-Nulth of the Pacific(More)
There is evidence that Amerindians have continuously occupied the lower Central American Isthmus for as long as 10,000 years. There remains some doubt about the relationships of these original colonizers to the resident peoples of this zone at the time of European contact (approximately A.D. 1500). We present new genetic data for up to 48 genetic loci for(More)
The development of CYP2D6 has been attributed to the need of earth-dwelling animals to detoxify toxic xenobiotics (phytoalexins) present in plants. This hypothesis has been extrapolated to humans, but is yet unconfirmed. Therefore, we studied two Amerindian populations as the best available model to test the effect of selection through diet on human CYP2D6(More)
1. The metabolic oxidation of debrisoquine (DB) was studied in 89 non-related Cuna Amerindian subjects. 2. Means and standard deviations for urinary recoveries of the intact drug and its 4-hydroxy metabolite (4-HD) were: %DB: 6.8 +/- 4.5; %4-HD: 16.0 +/- 9.1; %sum: 22.8 +/- 12.0. The log10 metabolic ratios for DB (LMRDB) were distributed within a single(More)
The oxidation of sparteine was studied in a total of 121 Ngawbé Guaymí volunteers in Panama, 97 of whom were unrelated. When presented in a frequency histogram, the results of the log10 of the metabolic ratios (LMR) indicated the existence of two modes, the largest of which exhibited a normal distribution (alpha = 0.05; chi 2 = 5.46). A preliminary(More)
Six NAT2 single-nucleotide polymorphisms (SNPs) were analysed in 105 unrelated Ngawbe and 136 unrelated Embera Amerindians (482 chromosomes) by SNP-specific polymerase chain reaction analysis. 282C>T was the most common synonymous mutation, while 857G>A was the most frequent nonsynonymous inactivating exchange. The allelic frequency of the NAT2*5 series(More)
Nine STR loci (CSF1PO, TPOX, TH01, F13A01, FESFPS, VWA, D16S539, D7S820, and D13S317) were analyzed in unrelated Ngöbé and Emberá Amerindians of Panama. The chi-square test demonstrated statistically significant differences (P < 0.001) in the allele frequencies for all markers except one (D16S539; P < 0.01). Both populations shared their alleles with the(More)
Various conventions have been used to express the activity of polymorphic hepatic N-acetyltransferase of isoniazid. Among them, two of the most common are the "percentage of acetylisoniazid" and the "inactivation index." A third alternative convention is proposed, the "molar acetylation ratio," which showed the most clear-cut bimodal distribution when(More)