410 research outputs found

    Ileosigmoid fistula and delayed ileal obstruction secondary to blunt abdominal trauma: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Abdominal trauma is a source of significant mortality and morbidity. Bowel injury as a result of blunt abdominal trauma is usually evident within hours or days of the accident.</p> <p>Case presentation</p> <p>A 38-year-old Caucasian Greek man presented with a subtle and delayed small bowel obstruction caused by a post-traumatic ileosigmoid fistula and ileal stricture four months after a road traffic accident.</p> <p>Conclusion</p> <p>Delayed occurrence of post-traumatic small bowel stricture and ileosigmoid fistula is an uncommon surgical emergency. General surgeons as well as emergency physicians should bear this manifestation in mind should a patient return to the hospital several weeks or even years after blunt abdominal trauma with symptoms or signs of bowel obstruction.</p

    An efficient multiplex genotyping approach for detecting the major worldwide human Y-chromosome haplogroups

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    The Y chromosome is paternally inherited and therefore serves as an evolutionary marker of patrilineal descent. Worldwide DNA variation within the non-recombining portion of the Y chromosome can be represented as a monophyletic phylogenetic tree in which the branches (haplogroups) are defined by at least one SNP. Previous human population genetics research has produced a wealth of knowledge about the worldwide distribution of Y-SNP haplogroups. Here, we apply previous and very recent knowledge on the Y-SNP phylogeny and Y-haplogroup distribution by introducing two multiplex genotyping assays that allow for the hierarchical detection of 28 Y-SNPs defining the major worldwide Y haplogroups. PCR amplicons were kept small to make the method sensitive and thereby applicable to DNA of limited amount and/or quality such as in forensic settings. These Y-SNP assays thus form a valuable tool for researchers in the fields of forensic genetics and genetic anthropology to infer a man's patrilineal bio-geographic ancestry from DNA

    Recombination dynamics of a human Y-chromosomal palindrome:rapid GC-biased gene conversion, multi-kilobase conversion tracts, and rare inversions

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    The male-specific region of the human Y chromosome (MSY) includes eight large inverted repeats (palindromes) in which arm-to-arm similarity exceeds 99.9%, due to gene conversion activity. Here, we studied one of these palindromes, P6, in order to illuminate the dynamics of the gene conversion process. We genotyped ten paralogous sequence variants (PSVs) within the arms of P6 in 378 Y chromosomes whose evolutionary relationships within the SNP-defined Y phylogeny are known. This allowed the identification of 146 historical gene conversion events involving individual PSVs, occurring at a rate of 2.9-8.4×10(-4) events per generation. A consideration of the nature of nucleotide change and the ancestral state of each PSV showed that the conversion process was significantly biased towards the fixation of G or C nucleotides (GC-biased), and also towards the ancestral state. Determination of haplotypes by long-PCR allowed likely co-conversion of PSVs to be identified, and suggested that conversion tract lengths are large, with a mean of 2068 bp, and a maximum in excess of 9 kb. Despite the frequent formation of recombination intermediates implied by the rapid observed gene conversion activity, resolution via crossover is rare: only three inversions within P6 were detected in the sample. An analysis of chimpanzee and gorilla P6 orthologs showed that the ancestral state bias has existed in all three species, and comparison of human and chimpanzee sequences with the gorilla outgroup confirmed that GC bias of the conversion process has apparently been active in both the human and chimpanzee lineages

    MPI-PHYLIP: Parallelizing Computationally Intensive Phylogenetic Analysis Routines for the Analysis of Large Protein Families

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    Background: Phylogenetic study of protein sequences provides unique and valuable insights into the molecular and genetic basis of important medical and epidemiological problems as well as insights about the origins and development of physiological features in present day organisms. Consensus phylogenies based on the bootstrap and other resampling methods play a crucial part in analyzing the robustness of the trees produced for these analyses. Methodology: Our focus was to increase the number of bootstrap replications that can be performed on large protein datasets using the maximum parsimony, distance matrix, and maximum likelihood methods. We have modified the PHYLIP package using MPI to enable large-scale phylogenetic study of protein sequences, using a statistically robust number of bootstrapped datasets, to be performed in a moderate amount of time. This paper discusses the methodology used to parallelize the PHYLIP programs and reports the performance of the parallel PHYLIP programs that are relevant to the study of protein evolution on several protein datasets. Conclusions: Calculations that currently take a few days on a state of the art desktop workstation are reduced to calculations that can be performed over lunchtime on a modern parallel computer. Of the three protein methods tested, the maximum likelihood method scales the best, followed by the distance method, and then the maximum parsimony method. However, the maximum likelihood method requires significant memory resources, which limits its application to mor

    Factors associated with default from treatment among tuberculosis patients in nairobi province, Kenya: A case control study

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    <p>Abstract</p> <p>Background</p> <p>Successful treatment of tuberculosis (TB) involves taking anti-tuberculosis drugs for at least six months. Poor adherence to treatment means patients remain infectious for longer, are more likely to relapse or succumb to tuberculosis and could result in treatment failure as well as foster emergence of drug resistant tuberculosis. Kenya is among countries with high tuberculosis burden globally. The purpose of this study was to determine the duration tuberculosis patients stay in treatment before defaulting and factors associated with default in Nairobi.</p> <p>Methods</p> <p>A Case-Control study; Cases were those who defaulted from treatment and Controls those who completed treatment course between January 2006 and March 2008. All (945) defaulters and 1033 randomly selected controls from among 5659 patients who completed treatment course in 30 high volume sites were enrolled. Secondary data was collected using a facility questionnaire. From among the enrolled, 120 cases and 154 controls were randomly selected and interviewed to obtain primary data not routinely collected. Data was analyzed using SPSS and Epi Info statistical software. Univariate and multivariate logistic regression analysis to determine association and Kaplan-Meier method to determine probability of staying in treatment over time were applied.</p> <p>Results</p> <p>Of 945 defaulters, 22.7% (215) and 20.4% (193) abandoned treatment within first and second months (intensive phase) of treatment respectively. Among 120 defaulters interviewed, 16.7% (20) attributed their default to ignorance, 12.5% (15) to traveling away from treatment site, 11.7% (14) to feeling better and 10.8% (13) to side-effects. On multivariate analysis, inadequate knowledge on tuberculosis (OR 8.67; 95% CI 1.47-51.3), herbal medication use (OR 5.7; 95% CI 1.37-23.7), low income (OR 5.57, CI 1.07-30.0), alcohol abuse (OR 4.97; 95% CI 1.56-15.9), previous default (OR 2.33; 95% CI 1.16-4.68), co-infection with Human immune-deficient Virus (HIV) (OR 1.56; 95% CI 1.25-1.94) and male gender (OR 1.43; 95% CI 1.15-1.78) were independently associated with default.</p> <p>Conclusion</p> <p>The rate of defaulting was highest during initial two months, the intensive phase of treatment. Multiple factors were attributed by defaulting patients as cause for abandoning treatment whereas several were independently associated with default. Enhanced patient pre-treatment counseling and education about TB is recommended.</p

    An anthropogenic habitat facilitates the establishment of non-native birds by providing underexploited resources

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    Anthropogenic modification of habitats may reduce the resources available for native species, leading to population declines and extinction. These same habitats often have the highest richness of non-native species. This pattern may be explained if recently human-modified habitats provide novel resources that are more accessible to non-native species than native species. Using non-native birds in the Iberian Peninsula as a case study, we conduct a large-scale study to investigate whether non-native species are positively associated with human modified habitats, and to investigate whether this positive association may be driven by the presence of resources that are not fully exploited by native species. We do this by comparing the functional diversity and resource use of native and non-native bird communities in a recently human-modified habitat (rice fields) and in more traditional habitats in the Iberian Peninsula. The functional diversity of native bird communities was lower in rice fields, but non-native birds were positively associated with rice fields and plugged this gap. Differences in resource use between native and non-native species allowed non-native species to exploit resources that were plentiful in rice fields, supporting the role of underexploited resources in driving the positive association of non-native birds with rice fields. Our results provide a potential mechanism explaining the positive association of non-native species with anthropogenic habitats, and further work is needed to test if this applies more generally

    Extended Y chromosome haplotypes resolve multiple and unique lineages of the Jewish priesthood

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    It has been known for over a decade that a majority of men who self report as members of the Jewish priesthood (Cohanim) carry a characteristic Y chromosome haplotype termed the Cohen Modal Haplotype (CMH). The CMH has since been used to trace putative Jewish ancestral origins of various populations. However, the limited number of binary and STR Y chromosome markers used previously did not provide the phylogenetic resolution needed to infer the number of independent paternal lineages that are encompassed within the Cohanim or their coalescence times. Accordingly, we have genotyped 75 binary markers and 12 Y-STRs in a sample of 215 Cohanim from diverse Jewish communities, 1,575 Jewish men from across the range of the Jewish Diaspora, and 2,099 non-Jewish men from the Near East, Europe, Central Asia, and India. While Cohanim from diverse backgrounds carry a total of 21 Y chromosome haplogroups, 5 haplogroups account for 79.5% of Cohanim Y chromosomes. The most frequent Cohanim lineage (46.1%) is marked by the recently reported P58 T->C mutation, which is prevalent in the Near East. Based on genotypes at 12 Y-STRs, we identify an extended CMH on the J-P58* background that predominates in both Ashkenazi and non-Ashkenazi Cohanim and is remarkably absent in non-Jews. The estimated divergence time of this lineage based on 17 STRs is 3,190 ± 1,090 years. Notably, the second most frequent Cohanim lineage (J-M410*, 14.4%) contains an extended modal haplotype that is also limited to Ashkenazi and non-Ashkenazi Cohanim and is estimated to be 4.2 ± 1.3 ky old. These results support the hypothesis of a common origin of the CMH in the Near East well before the dispersion of the Jewish people into separate communities, and indicate that the majority of contemporary Jewish priests descend from a limited number of paternal lineages

    Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.

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    OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age
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