85 research outputs found
Mitochondrial echoes of first settlement and genetic continuity in El Salvador
Background: From Paleo-Indian times to recent historical episodes, the Mesoamerican isthmus played an important role in the distribution and patterns of variability all around the double American continent. However, the amount of genetic information currently available on Central American continental populations is very scarce. In order to shed light on the role of Mesoamerica in the peopling of the New World, the present study focuses on the analysis of the mtDNA variation in a population sample from El Salvador.
Methodology/Principal Findings: We have carried out DNA sequencing of the entire control region of the mitochondrial DNA (mtDNA) genome in 90 individuals from El Salvador. We have also compiled more than 3,985 control region profiles from the public domain and the literature in order to carry out inter-population comparisons. The results reveal a predominant Native American component in this region: by far, the most prevalent mtDNA haplogroup in this country (at ~90%) is A2, in contrast with other North, Meso- and South American populations. Haplogroup A2 shows a star-like phylogeny and is very diverse with a substantial proportion of mtDNAs (45%; sequence range 16090–16365) still unobserved in other American populations. Two different Bayesian approaches used to estimate admixture proportions in El Salvador shows that the majority of the mtDNAs observed come from North America. A preliminary founder analysis indicates that the settlement of El Salvador occurred about 13,400±5,200 Y.B.P.. The founder age of A2 in El Salvador is close to the overall age of A2 in America, which suggests that the colonization of this region occurred within a few thousand years of the initial expansion into the Americas.
Conclusions/Significance: As a whole, the results are compatible with the hypothesis that today's A2 variability in El Salvador represents to a large extent the indigenous component of the region. Concordant with this hypothesis is also the observation of a very limited contribution from European and African women (~5%). This implies that the Atlantic slave trade had a very small demographic impact in El Salvador in contrast to its transformation of the gene pool in neighbouring populations from the Caribbean facade
First-time mothers’ experiences of pregnancy and birth following assisted reproductive technology treatment in Taiwan
Background
Assisted Reproductive Technology (ART) treatment tends to involve significant physical and emotional commitments that can impact maternal, infant and family health and well-being. An in-depth understanding of experiences is necessary to provide adequate support for women and their families during pregnancy and transition to parenthood following ART treatment. The aim of this study was to explore first-time mothers’ experiences of pregnancy and transition to parenthood following successful ART treatment in Taiwan.
Method
Twelve first-time mothers who conceived and gave live birth using ART treatment were purposively selected from a fertility centre in Taipei, Taiwan. Women’s experiences in pregnancy and in their transition to motherhood were explored using semi-structured in-depth interviews. All interviews were recorded, transcribed, and analysed using the Colaizzi strategy.
Results
The mothers’ accounts reflected three main themes: ‘being different from mothers who became pregnant naturally’; ‘ensuring health and safety of the foetus’; and ‘welcoming new lives with excitement’. The difference mothers felt about themselves was evident in four subthemes: becoming pregnant after a long wait, feeling vulnerable during pregnancy, relying on family’s assistance and support, and worrying about the impact of ART on health. The theme on ‘ensuring health and safety of the foetus’ encompassed three subthemes: activities to protect the unborn baby, monitoring foetal movement constantly to maintain peace of mind, and receiving foetal reduction for the sake of the pregnancy. Narratives around ‘welcoming new lives with excitement’ reflected four subthemes: overcoming hardship for worthwhile results, realising one’s life and dreams, proving to be fertile enough to give birth, and return to normal life track.
Conclusion
Findings indicate the need for educational and psychosocial interventions to support women and their families physically and psychologically during ART treatment. The stigma related to infertility and the psychosocial support from family are aspects to consider while planning intervention programmes
Physicochemical and sensory changes in aged sugarcane spirit submitted to filtering with activated carbon filter
Polymorphisms in regulatory regions of Cyclooxygenase-2 gene and breast cancer risk in Brazilians: a case-control study
<p>Abstract</p> <p>Background</p> <p>Cyclooxygenase-2 (COX-2) is up-regulated in several types of cancer, and it is hypothesized that COX-2 expression may be genetically influenced. Here, we evaluate the association between single-nucleotide polymorphisms (SNPs) in the COX-2 gene (<it>PTGS2</it>) and the occurrence of breast cancer among Brazilian women.</p> <p>Methods</p> <p>The study was conducted prospectively in two steps: First, we screened the promoter region and three fragments of the 3'-untranslated region of <it>PTGS2 </it>from 67 healthy Brazilians to identify SNPs and to select those with a minor allele frequency (MAF) of at least 0.10. The MAF of these selected SNPs was further characterized in 402 healthy volunteers to evaluate potential differences related to heterogeneous racial admixture and to estimate the existence of linkage disequilibrium among the SNPs. The second step was a case-control study with 318 patients and 273 controls designed to evaluate <it>PTGS2 </it>genotype- or haplotype-associated risk of breast cancer.</p> <p>Results</p> <p>The screening analysis indicated nine SNPs with the following MAFs: rs689465 (0.22), rs689466 (0.15), rs20415 (0.007), rs20417 (0.32), rs20419 (0.015), rs5270 (0.02), rs20424 (0.007), rs5275 (0.22) and rs4648298 (0.01). The SNPs rs689465, rs689466, rs20417 and rs5275 were further studied: Their genotypic distributions followed Hardy-Weinberg equilibrium and the MAFs were not affected by gender or skin color. Strong linkage disequilibrium was detected for rs689465, rs20417 and rs5275 in the three possible pairwise combinations. In the case-control study, there was a significant increase of rs5275TC heterozygotes in cases compared to controls (OR = 1.44, 95% CI = 1.01-2.06; P = 0.043), and the haplotype formed by rs689465G, rs689466A, rs20417G and rs5275C was only detected in cases. The apparent association with breast cancer was not confirmed for rs5275CC homozygotes or for the most frequent rs5275C-containing haplotypes.</p> <p>Conclusions</p> <p>Our results indicate no strong association between the four most frequent <it>PTGS2 </it>SNPs and the risk of breast cancer.</p
O modelo dos múltiplos fluxos de Kingdon na análise de políticas de saúde: aplicabilidades, contribuições e limites
Influence of antimicrobial solutions in the decontamination and adhesion of glass-fiber posts to root canals
A procedure to analyze the viability of rainwater harvesting systems in urban areas based on pre-defined diagrams
Duffy blood group gene polymorphisms among malaria vivax patients in four areas of the Brazilian Amazon region
<p>Abstract</p> <p>Background</p> <p>Duffy blood group polymorphisms are important in areas where <it>Plasmodium vivax </it>predominates, because this molecule acts as a receptor for this protozoan. In the present study, Duffy blood group genotyping in <it>P. vivax </it>malaria patients from four different Brazilian endemic areas is reported, exploring significant associations between blood group variants and susceptibility or resistance to malaria.</p> <p>Methods</p> <p>The <it>P. vivax </it>identification was determined by non-genotypic and genotypic screening tests. The Duffy blood group was genotyped by PCR/RFLP in 330 blood donors and 312 malaria patients from four Brazilian Amazon areas. In order to assess the variables significance and to obtain independence among the proportions, the Fisher's exact test was used.</p> <p>Results</p> <p>The data show a high frequency of the <it>FYA/FYB </it>genotype, followed by <it>FYB/FYB, FYA/FYA</it>, <it>FYA/FYB-33 </it>and <it>FYB/FYB-33</it>. Low frequencies were detected for the <it>FYA/FY</it><sup><it>X</it></sup>, <it>FYB/FY</it><sup><it>X</it></sup>, <it>FYX/FY</it><sup><it>X </it></sup>and <it>FYB-33/FYB-33 </it>genotypes. Negative Duffy genotype (<it>FYB-33/FYB-33</it>) was found in both groups: individuals infected and non-infected (blood donors). No individual carried the <it>FY</it><sup><it>X</it></sup><it>/FYB-33 </it>genotype. Some of the Duffy genotypes frequencies showed significant differences between donors and malaria patients.</p> <p>Conclusion</p> <p>The obtained data suggest that individuals with the <it>FYA/FYB </it>genotype have higher susceptibility to malaria. The presence of the <it>FYB-33 </it>allele may be a selective advantage in the population, reducing the rate of infection by <it>P. vivax </it>in this region. Additional efforts may contribute to better elucidate the physiopathologic differences in this parasite/host relationship in regions endemic for <it>P. vivax </it>malaria, in particular the Brazilian Amazon region.</p
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