204 resultados para Epidemiology, Molecular
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Background: Major depression is one of the leading causes of disability worldwide, yet epidemiologic data are not available for many countries, particularly low- to middle-income countries. In this paper, we present data on the prevalence, impairment and demographic correlates of depression from 18 high and low-to middle-income countries in the World Mental Health Survey Initiative. Methods: Major depressive episodes (MDE) as defined by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DMS-IV) were evaluated in face-to-face interviews using the World Health Organization Composite International Diagnostic Interview (CIDI). Data from 18 countries were analyzed in this report (n = 89,037). All countries surveyed representative, population-based samples of adults. Results: The average lifetime and 12-month prevalence estimates of DSM-IV MDE were 14.6% and 5.5% in the ten high-income and 11.1% and 5.9% in the eight low- to middle-income countries. The average age of onset ascertained retrospectively was 25.7 in the high-income and 24.0 in low- to middle-income countries. Functional impairment was associated with recency of MDE. The female: male ratio was about 2: 1. In high-income countries, younger age was associated with higher 12-month prevalence; by contrast, in several low-to middle-income countries, older age was associated with greater likelihood of MDE. The strongest demographic correlate in high-income countries was being separated from a partner, and in low- to middle-income countries, was being divorced or widowed. Conclusions: MDE is a significant public-health concern across all regions of the world and is strongly linked to social conditions. Future research is needed to investigate the combination of demographic risk factors that are most strongly associated with MDE in the specific countries included in the WMH.
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Background: Hepatitis B virus (HBV) can be classified into nine genotypes (A-I) defined by sequence divergence of more than 8% based on the complete genome. This study aims to identify the genotypic distribution of HBV in 40 HBsAg-positive patients from Rondonia, Brazil. A fragment of 1306 bp partially comprising surface and polymerase overlapping genes was amplified by PCR. Amplified DNA was purified and sequenced. Amplified DNA was purified and sequenced on an ABI PRISM (R) 377 Automatic Sequencer (Applied Biosystems, Foster City, CA, USA). The obtained sequences were aligned with reference sequences obtained from the GenBank using Clustal X software and then edited with Se-Al software. Phylogenetic analyses were conducted by the Markov Chain Monte Carlo (MCMC) approach using BEAST v.1.5.3. Results: The subgenotypes distribution was A1 (37.1%), D3 (22.8%), F2a (20.0%), D4 (17.1%) and D2 (2.8%). Conclusions: These results for the first HBV genotypic characterization in Rondonia state are consistent with other studies in Brazil, showing the presence of several HBV genotypes that reflects the mixed origin of the population, involving descendants from Native Americans, Europeans, and Africans.
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Background: Ser-249 TP53 mutation (249(Ser)) is a molecular evidence for aflatoxin-related carcinogenesis in Hepatocellular Carcinoma (HCC) and it is frequent in some African and Asian regions, but it is unusual in Western countries. HBV has been claimed to add a synergic effect on genesis of this particular mutation with aflatoxin. The aim of this study was to investigate the frequency of 249Ser mutation in HCC from patients in Brazil. Methods: We studied 74 HCC formalin fixed paraffin blocks samples of patients whom underwent surgical resection in Brazil. 249Ser mutation was analyzed by RFLP and DNA sequencing. HBV DNA presence was determined by Real-Time PCR. Results: 249Ser mutation was found in 21/74 (28%) samples while HBV DNA was detected in 13/74 (16%). 249Ser mutation was detected in 21/74 samples by RFLP assay, of which 14 were confirmed by 249Ser mutant-specific PCR, and 12 by nucleic acid sequencing. All HCC cases with p53-249ser mutation displayed also wild-type p53 sequences. Poorly differentiated HCC was more likely to have 249Ser mutation (OR = 2.415, 95% CI = 1.001 - 5.824, p = 0.05). The mean size of 249Ser HCC tumor was 9.4 cm versus 5.5 cm on wild type HCC (p = 0.012). HBV DNA detection was not related to 249Ser mutation. Conclusion: Our results indicate that 249Ser mutation is a HCC important factor of carcinogenesis in Brazil and it is associated to large and poorly differentiated tumors.
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Background: The Brazilian population is mainly descendant from European colonizers, Africans and Native Americans. Some Afro-descendants lived in small isolated communities since the slavery period. The epidemiological status of HBV infection in Quilombos communities from northeast of Brazil remains unknown. The aim of this study was to characterize the HBV genotypes circulating inside a Quilombo isolated community from Maranhao State, Brazil. Methods: Seventy-two samples from Frechal Quilombo community at Maranhao were collected. All serum samples were screened by enzyme-linked immunosorbent assays for the presence of hepatitis B surface antigen ( HBsAg). HBsAg positive samples were submitted to DNA extraction and a fragment of 1306 bp partially comprising HBsAg and polymerase coding regions (S/POL) was amplified by nested PCR and its nucleotide sequence was determined. Viral isolates were genotyped by phylogenetic analysis using reference sequences from each genotype obtained from GenBank (n = 320). Sequences were aligned using Muscle software and edited in the SE-AL software. Bayesian phylogenetic analyses were conducted using Markov Chain Monte Carlo (MCMC) method to obtain the MCC tree using BEAST v.1.5.3. Results: Of the 72 individuals, 9 (12.5%) were HBsAg-positive and 4 of them were successfully sequenced for the 1306 bp fragment. All these samples were genotype A1 and grouped together with other sequences reported from Brazil. Conclusions: The present study represents the first report on the HBV genotypes characterization of this community in the Maranhao state in Brazil where a high HBsAg frequency was found. In this study, we reported a high frequency of HBV infection and the exclusive presence of subgenotype A1 in an Afro-descendent community in the Maranhao State, Brazil.
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The dengue virus has a single-stranded positive-sense RNA genome of similar to 10.700 nucleotides with a single open reading frame that encodes three structural (C, prM, and E) and seven nonstructural (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins. It possesses four antigenically distinct serotypes (DENV 1-4). Many phylogenetic studies address particularities of the different serotypes using convenience samples that are not conducive to a spatio-temporal analysis in a single urban setting. We describe the pattern of spread of distinct lineages of DENV-3 circulating in Sao Jose do Rio Preto, Brazil, during 2006. Blood samples from patients presenting dengue-like symptoms were collected for DENV testing. We performed M-N-PCR using primers based on NS5 for virus detection and identification. The fragments were purified from PCR mixtures and sequenced. The positive dengue cases were geo-coded. To type the sequenced samples, 52 reference sequences were aligned. The dataset generated was used for iterative phylogenetic reconstruction with the maximum likelihood criterion. The best demographic model, the rate of growth, rate of evolutionary change, and Time to Most Recent Common Ancestor (TMRCA) were estimated. The basic reproductive rate during the epidemics was estimated. We obtained sequences from 82 patients among 174 blood samples. We were able to geo-code 46 sequences. The alignment generated a 399-nucleotide-long dataset with 134 taxa. The phylogenetic analysis indicated that all samples were of DENV-3 and related to strains circulating on the isle of Martinique in 2000-2001. Sixty DENV-3 from Sao Jose do Rio Preto formed a monophyletic group (lineage 1), closely related to the remaining 22 isolates (lineage 2). We assumed that these lineages appeared before 2006 in different occasions. By transforming the inferred exponential growth rates into the basic reproductive rate, we obtained values for lineage 1 of R(0) = 1.53 and values for lineage 2 of R(0) = 1.13. Under the exponential model, TMRCA of lineage 1 dated 1 year and lineage 2 dated 3.4 years before the last sampling. The possibility of inferring the spatio-temporal dynamics from genetic data has been generally little explored, and it may shed light on DENV circulation. The use of both geographic and temporally structured phylogenetic data provided a detailed view on the spread of at least two dengue viral strains in a populated urban area.
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Background: Leishmania (Viannia) braziliensis is a parasite recognized as the most important etiologic agent of mucosal leishmaniasis (ML) in the New World. In Amazonia, seven different species of Leishmania, etiologic agents of human Cutaneous Leishmaniasis, have been described. Isolated cases of ML have been described for several different species of Leishmania: L. (V.) panamensis, L. (V.) guyanensis and L. (L.) amazonensis. Methodology: Leishmania species were characterized by polymerase chain reaction (PCR) of tissues taken from mucosal biopsies of Amazonian patients who were diagnosed with ML and treated at the Tropical Medicine Foundation of Amazonas (FMTAM) in Manaus, Amazonas state, Brazil. Samples were obtained retrospectively from the pathology laboratory and prospectively from patients attending the aforementioned tertiary care unit. Results: This study reports 46 cases of ML along with their geographical origin, 30 cases caused by L. (V.) braziliensis and 16 cases by L. (V.) guyanensis. This is the first record of ML cases in 16 different municipalities in the state of Amazonas and of simultaneous detection of both species in 4 municipalities of this state. It is also the first record of ML caused by L. (V.) guyanensis in the states of Para, Acre, and Rondonia and cases of ML caused by L. (V.) braziliensis in the state of Rondonia. Conclusions/Significance: L. (V.) braziliensis is the predominant species that causes ML in the Amazon region. However, contrary to previous studies, L. (V.) guyanensis is also a significant causative agent of ML within the region. The clinical and epidemiological expression of ML in the Manaus region is similar to the rest of the country, although the majority of ML cases are found south of the Amazon River.
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Chagas disease caused by Trypanosoma cruzi is a complex disease that is endemic and an important problem in public health in Latin America. The T. cruzi parasite is classified into six discrete taxonomic units (DTUs) based on the recently proposed nomenclature (TcI, TcII, TcIII, TcIV, TcV and TcVI). The discovery of genetic variability within TcI showed the presence of five genotypes (Ia, Ib, Ic, Id and Ie) related to the transmission cycle of Chagas disease. In Colombia, TcI is more prevalent but TcII has also been reported, as has mixed infection by both TcI and TcII in the same Chagasic patient. The objectives of this study were to determine the T. cruzi DTUs that are circulating in Colombian chronic Chagasic patients and to obtain more information about the molecular epidemiology of Chagas disease in Colombia. We also assessed the presence of electrocardiographic, radiologic and echocardiographic abnormalities with the purpose of correlating T. cruzi genetic variability and cardiac disease. Molecular characterization was performed in Colombian adult chronic Chagasic patients based on the intergenic region of the mini-exon gene, the 24S alpha and 18S regions of rDNA and the variable region of satellite DNA, whereby the presence of T. cruzi I, II, III and IV was detected. In our population, mixed infections also occurred, with TcI-TcII, TcI-TcIII and TcI-TcIV, as well as the existence of the TcI genotypes showing the presence of genotypes Ia and Id. Patients infected with TcI demonstrated a higher prevalence of cardiac alterations than those infected with TcII. These results corroborate the predominance of TcI in Colombia and show the first report of TcIII and TcIV in Colombian Chagasic patients. Findings also indicate that Chagas cardiomyopathy manifestations are more correlated with TcI than with TcII in Colombia.
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In the present study, we investigated the relationship between polymorphisms in the estrogen-metabolizing genes CYP17, CYP1B1, CYP1A1, and COMT and genomic instability in the peripheral blood lymphocytes of 62 BC patients and 62 controls considering that increased or prolonged exposure to estrogen can damage the DNA molecule and increase the genomic instability process in breast tissue. Our data demonstrated increased genomic instability in BC patients and that individuals with higher frequencies of MN exhibited higher risk to BC when belonging Val/Met genotype of the COMT gene. We also observed that CYP17 and CYP1A1 polymorphisms can modify the risk to BC depending on the menopause status. We can conclude that the genetic background in estrogen metabolism pathway can modulate chromosome damage in healthy controls and patients and thereby influence the risk to BC. These findings suggest the importance to ally biomarkers of susceptibility and effects to estimate risk groups.
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During 2010, 15 adult ticks, identified as Amblyomma cajennense, were collected from horses in Cahuita and Turrialba districts, whereas 7 fleas, identified as Ctenocephalides felis, were collected from a dog in San Jose city, Costa Rica. In the laboratory, three A. cajennense specimens, two from Cahuita and one from Turrialba, were individually processed for rickettsial isolation in cell culture, as was a pool of seven fleas. Rickettsiae were successfully isolated and established in Vero cell culture from the three ticks and from a pool of seven fleas in C6/36 cell culture. The three tick isolates were genotypically identified as Rickettsia amblyommii, and the flea isolate was identified as Rickettsia felis through DNA sequencing of portions of the rickettsial genes gltA, ompA, and ompB of each isolate. In addition, other seven ticks were shown to contain rickettsial DNA. Polymerase chain reaction products of at least two of these ticks were sequenced and also showed to correspond to R. amblyommii. Overall, 66.7% (10/15) of the A. cajennense adult ticks were found to be infected with rickettsiae. This is the first report of a successful isolation in cell culture of R. amblyommii and R. felis from Central America.
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The complete genome sequences of two Brazilian wild-type rabies viruses (RABV), a BR-DR1 isolate from a haematophagous bat (Desmodus rotundus) and a BR-AL1 isolate from a frugivorous bat (Artibeus lituratus), were determined. The genomes of the BR-DR1 and RR-AL1 had 11,923 and 11,922 nt, respectively, and both encoded the five standard genes of rhabdoviruses. The complete nucleotide sequence identity between the BR-DR1 and BR-AL1 isolates was 97%. The BR-DR1 and BR-AL1 isolates had some conserved functional sites revealed by the fixed isolates, whereas both isolates had unique amino acid substitutions in the antigenic region IV of the nucleocapsid gene. Therefore, it is speculated that both isolates were nearly identical in virologic character. According to our phylogenetic analysis based on the complete genomes, both isolates belonged to genotype 1, and to the previously defined ""vampire bat-related RABV lineage"" which consisted of mainly D. rotundus- and A. lituratus- isolates; however, a branch pattern with high bootstrap values suggested that BR-DR1 was more closely related to the 9001FRA isolate, which was collected from a dog bitten by a bat in French Guiana, than to BR-AL1. This result suggests that the vampire bat-related RABV lineage includes Brazilian vampire bat and Brazilian frugivorous bat RABV and is further divided into Brazilian vampire bat and Brazilian frugivorous bat RABV sub-lineages. The phylogenetic analysis based on the complete genomes was valuable in discriminating among very closely related isolates.
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The aim of the present study was to examine the impact of polymorphisms in prostate-specific antigen (PSA) and androgen-related genes (AR, CYP17, and CYP19) on prostate cancer (PCa) risk in selected high-risk patients who underwent prostate biopsy. Blood samples and prostate tissues were obtained for DNA analysis. Single-nucleotide polymorphisms in the 50-untranslated regions (UTRs) of the PSA (substitution A > G at position -158) and CYP17 (substitution T > C at 50-UTR) genes were detected by polymerase chain reaction (PCR)-restriction fragment length polymorphism assays. The CAG and TTTA repeats in the AR and CYP19 genes, respectively, were genotyped by PCR-based GeneScan analysis. Patients with the GG genotype of the PSA gene had a higher risk of PCa than those with the AG or AA genotype (OR = 3.79, p = 0.00138). The AA genotype was associated with lower PSA levels (6.44 +/- 1.64 ng/mL) compared with genotypes having at least one G allele (10.44 +/- 10.06 ng/mL) (p = 0.0687, 95% CI - 0.3146 to 8.315, unpaired t-test). The multivariate analysis confirmed the association between PSA levels and PSA genotypes (AA vs. AG+GG; chi(2) = 0.0482) and CYP19 (short alleles homozygous vs. at least one long allele; chi(2) = 0.0110) genotypes. Genetic instability at the AR locus leading to somatic mosaicism was detected in one PCa patient by comparing the length of AR CAG repeats in matched peripheral blood and prostate biopsy cores. Taken together, these findings suggest that the PSA genotype should be a clinically relevant biomarker to predict the PCa risk.
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Background: Without intensive selection, the majority of bovine oocytes submitted to in vitro embryo production (IVP) fail to develop to the blastocyst stage. This is attributed partly to their maturation status and competences. Using the Affymetrix GeneChip Bovine Genome Array, global mRNA expression analysis of immature (GV) and in vitro matured (IVM) bovine oocytes was carried out to characterize the transcriptome of bovine oocytes and then use a variety of approaches to determine whether the observed transcriptional changes during IVM was real or an artifact of the techniques used during analysis. Results: 8489 transcripts were detected across the two oocyte groups, of which similar to 25.0% (2117 transcripts) were differentially expressed (p < 0.001); corresponding to 589 over-expressed and 1528 under-expressed transcripts in the IVM oocytes compared to their immature counterparts. Over expression of transcripts by IVM oocytes is particularly interesting, therefore, a variety of approaches were employed to determine whether the observed transcriptional changes during IVM were real or an artifact of the techniques used during analysis, including the analysis of transcript abundance in oocytes in vitro matured in the presence of a-amanitin. Subsets of the differentially expressed genes were also validated by quantitative real-time PCR (qPCR) and the gene expression data was classified according to gene ontology and pathway enrichment. Numerous cell cycle linked (CDC2, CDK5, CDK8, HSPA2, MAPK14, TXNL4B), molecular transport (STX5, STX17, SEC22A, SEC22B), and differentiation (NACA) related genes were found to be among the several over-expressed transcripts in GV oocytes compared to the matured counterparts, while ANXA1, PLAU, STC1and LUM were among the over-expressed genes after oocyte maturation. Conclusion: Using sequential experiments, we have shown and confirmed transcriptional changes during oocyte maturation. This dataset provides a unique reference resource for studies concerned with the molecular mechanisms controlling oocyte meiotic maturation in cattle, addresses the existing conflicting issue of transcription during meiotic maturation and contributes to the global goal of improving assisted reproductive technology.
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Selection of zebu (Bos indicus) beef and dairy cattle in Brazil and the validation process of genetic markers for growth, carcass and meat quality traits and also for milk production, fat and protein milk content are discussed as concerned to the concepts and details of their use as auxiliary tools in selection processes. It is highlighted, also, the importance of right selection of ova donor cows for production of embryos to be transferred.
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Background: The thin-spined porcupine, also known as the bristle-spined rat, Chaetomys subspinosus (Olfers, 1818), the only member of its genus, figures among Brazilian endangered species. In addition to being threatened, it is poorly known, and even its taxonomic status at the family level has long been controversial. The genus Chaetomys was originally regarded as a porcupine in the family Erethizontidae, but some authors classified it as a spiny-rat in the family Echimyidae. Although the dispute seems to be settled in favor of the erethizontid advocates, further discussion of its affinities should be based on a phylogenetic framework. In the present study, we used nucleotide-sequence data from the complete mitochondrial cytochrome b gene and karyotypic information to address this issue. Our molecular analyses included one individual of Chaetomys subspinosus from the state of Bahia in northeastern Brazil, and other hystricognaths. Results: All topologies recovered in our molecular phylogenetic analyses strongly supported Chaetomys subspinosus as a sister clade of the erethizontids. Cytogenetically, Chaetomys subspinosus showed 2n = 52 and FN = 76. Although the sexual pair could not be identified, we assumed that the X chromosome is biarmed. The karyotype included 13 large to medium metacentric and submetacentric chromosome pairs, one small subtelocentric pair, and 12 small acrocentric pairs. The subtelocentric pair 14 had a terminal secondary constriction in the short arm, corresponding to the nucleolar organizer region (Ag-NOR), similar to the erethizontid Sphiggurus villosus, 2n = 42 and FN = 76, and different from the echimyids, in which the secondary constriction is interstitial. Conclusion: Both molecular phylogenies and karyotypical evidence indicated that Chaetomys is closely related to the Erethizontidae rather than to the Echimyidae, although in a basal position relative to the rest of the Erethizontidae. The high levels of molecular and morphological divergence suggest that Chaetomys belongs to an early radiation of the Erethizontidae that may have occurred in the Early Miocene, and should be assigned to its own subfamily, the Chaetomyinae.
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Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a ""flipflop'' phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites.