770 resultados para Chromosome Disorders
Resumo:
The aerobactin-mediated iron uptake system encoded by pColV-K30 and other ColV plasmids has been associated with the ability of Escherichia coli strains to cause disease. We investigated whether the pColV-K30 aerobactin system is present in E. coli K1 VW187 isolated from a human neonate with meningitis. This strain exhibited a functional aerobactin-mediated iron uptake system, as assessed by a cross-feeding bioassay and by its sensitivity to cloacin, a bacteriocin that recognizes the outer membrane receptor for iron-aerobactin complexes. By using a variety of techniques, we could not find any plasmid harboring the aerobactin genes. Hybridization of restriction endonuclease-cleaved chromosomal DNA from strain VW187 with various clones containing subsets of the pColV-K30 aerobactin region showed that the aerobactin genes were located on a 10.5-kilobase-pair chromosomal HindIII restriction fragment which also contained IS1-like insertion sequences. The chromosomal aerobactin region showed a high degree of conservation when compared with the homologous region in plasmid pColV-K30, although it was located on a different restriction endonuclease site environment.
Resumo:
Autism is a neuro-developmental disorder defined by atypical social behaviour, of which atypical social attention behaviours are among the earliest clinical markers (Volkmar et al., 1997). Eye tracking studies using still images and movie clips have provided a method for the precise quantification of atypical social attention in ASD. This is generally characterised by diminished viewing of the most socially pertinent regions (eyes), and increased viewing of less socially informative regions (body, background, objects) (Klin et al., 2002; Riby & Hancock, 2008, 2009). Ecological validity within eye tracking studies has become an increasingly important issue. As of yet, however, little is known about the precise nature of the atypicalities of social attention in ASD in real-life. Objectives: To capture and quantify gaze patterns for children with an ASD within a real life setting, compared to two Typically Developing (TD) comparison groups. Methods: Nine children with an ASD were compared to two age matched TD groups – a verbal (N=9) and a non-verbal (N=9) comparison group. A real-life scenario was created involving an experimenter posing as a magician, and consisted of 3 segments: a conversation segment; a magic trick segment; and a puppet segment. The first segment explored children’s attentional preferences during a real-life conversation; the magic trick segment explored children’s use of the eyes as a communicative cue, and the puppet segment explored attention capture. Finally, part of the puppet section explored children’s use of facial information in response to an unexpected event. Results: The most striking difference between the groups was the diminished viewing of the eyes by the ASD group in comparison to both control groups. This was found particularly during the conversation segment, but also during the magic trick segment, and during the puppet segment. When in conversation, participants with ASD were found to spend a greater proportion time looking off-screen, in comparison to TD participants. There was also a tendency for the ASD group to spend a greater proportion of time looking to the mouth of the experimenter. During the magic trick segment, despite the fact that the eyes were not predictive of a correct location, both TD comparison groups continued to use the eyes as a communicative cue, whereas the ASD group did not. In the puppet segment, all three groups spent a similar amount of time looking between the puppet and regions of the experimenter’s face. However, in response to an unexpected event, the ASD group were significantly slower to fixate back on the experimenter’s face. Conclusions: The results demonstrate the reduced salience of socially pertinent information for children with ASD in real life, and they provide support for the findings from previous eye tracking studies involving scene viewing. However, the results also highlight a pattern looking off-screen for both the TD and ASD groups. This eye movement behaviour is likely to be associated specifically with real-life interaction, as it has functional relevance (Doherty-Sneddon et al., 2002). However, the fact that it is significantly increased in the ASD group has implications for their understanding of real life social interactions.
Resumo:
Barrett's esophagus is an increasingly common disease that is strongly associated with reflux of stomach acid and usually a hiatus hernia, and it strongly predisposes to esophageal adenocarcinoma (EAC), a tumor with a very poor prognosis. We report the first genome-wide association study on Barrett's esophagus, comprising 1,852 UK cases and 5,172 UK controls in the discovery stage and 5,986 cases and 12,825 controls in the replication stage. Variants at two loci were associated with disease risk: chromosome 6p21, rs9257809 (P(combined) = 4.09 × 10(-9); odds ratio (OR) = 1.21, 95% confidence interval (CI) =1.13-1.28), within the major histocompatibility complex locus, and chromosome 16q24, rs9936833 (P(combined) = 2.74 × 10(-10); OR = 1.14, 95% CI = 1.10-1.19), for which the closest protein-coding gene is FOXF1, which is implicated in esophageal development and structure. We found evidence that many common variants of small effect contribute to genetic susceptibility to Barrett's esophagus and that SNP alleles predisposing to obesity also increase risk for Barrett's esophagus.
Resumo:
The full extent to which inherited disorders occur in different breeds of domestic horse (Equus caballus) has not been previously been investigated. A systematic search was carried out to review scientific literature on inherited disorders in domestic horse breeds and examine patterns in potentially inherited disorders. A two-part search was conducted: (i) electronic bibliographic databases for published studies; and (ii) existing online databases of inherited disorders in animals. A total of 230 papers were identified, discussing 102 inherited disorders in the horse. Few cases (17) were found in which disorders were reported to have a direct link to a conformational or phenotypic trait. Forty-nine breeds of domestic horse were described as being predisposed to one or more inherited disorders, but such predispositions did not distinguish between genetic or environmental causes. There were few patterns in the number of disorders to which breeds were reportedly predisposed or in the extent to which disorders were researched. The structure and grouping of disorders presented here could assist with standardisation in the terminology used for describing inherited disorders. © 2012 Universities Federation for Animal Welfare The Old School.
Resumo:
In recent years, research on the roles of TRP channels in vascular function and disease has undergone a rapid expansion from tens of reports published in the early 2000s to several hundreds of papers published to date. Multiple TRP subtypes are expressed in vascular smooth muscle cells and endothelial cells, where they form diverse non-selective cation channels permeable to Ca2+. These channels mediate Ca2+ entry following receptor stimulation, Ca2+ store depletion and mechanical stimulation of vascular myocytes and endothelial cells. The complex molecular composition and signalling pathways leading to the activation of various vascular TRP channels and the growing evidence for their involvement in various vascular disorders, including dysregulation of vascular tone and hypertension, impaired endothelium-dependent vasodilatation, increased endothelial permeability, occlusive vascular disease, vascular injury and oxidative stress, are summarised and discussed in this review.
Resumo:
Large regions of recurrent genomic loss are common in cancers; however, with a few well-characterized exceptions, how they contribute to tumor pathogenesis remains largely obscure. Here we identified primate-restricted imprinting of a gene cluster on chromosome 20 in the region commonly deleted in chronic myeloid malignancies. We showed that a single heterozygous 20q deletion consistently resulted in the complete loss of expression of the imprinted genes L3MBTL1 and SGK2, indicative of a pathogenetic role for loss of the active paternally inherited locus. Concomitant loss of both L3MBTL1 and SGK2 dysregulated erythropoiesis and megakaryopoiesis, 2 lineages commonly affected in chronic myeloid malignancies, with distinct consequences in each lineage. We demonstrated that L3MBTL1 and SGK2 collaborated in the transcriptional regulation of MYC by influencing different aspects of chromatin structure. L3MBTL1 is known to regulate nucleosomal compaction, and we here showed that SGK2 inactivated BRG1, a key ATP-dependent helicase within the SWI/SNF complex that regulates nucleosomal positioning. These results demonstrate a link between an imprinted gene cluster and malignancy, reveal a new pathogenetic mechanism associated with acquired regions of genomic loss, and underline the complex molecular and cellular consequences of "simple" cancer-associated chromosome deletions.
Resumo:
Ovarian cancer is a leading cause of gynaecological cancer-related morbidity and mortality. There has been increasing interest in the potential utility of anti-human epidermal growth factor receptor 2 (anti-HER2) agents in the treatment of this disease, with the attendant need to identify suitable predictive biomarkers of response to treatment.
Resumo:
Determination of HER2 protein expression by immunohistochemistry (IHC) and genomic status by fluorescent in situ hybridisation (FISH) are important in identifying a subset of high HER2-expressing gastric cancers that might respond to trastuzumab. Although FISH is considered the standard for determination of HER2 genomic status, brightfield ISH is being increasingly recognised as a viable alternative. Also, the impact of HER2 protein expression/genomic heterogeneity on the accuracy of HER2 testing has not been well studied in the context of gastric biopsy samples.
Resumo:
Objective: The authors evaluated and synthesised the best-available evidence relating to the effectiveness of CJLD service models with respect to changes in mental health status and/or criminal recidivism.Methods: Research examining the effectiveness of CJLD services when compared to traditional Criminal Justice System (CJS) responses was reviewed and systematically appraised according to Campbell/Cochrane guidelines. Key outcomes included a reduction in offending and post-intervention changes in mental health. Results: Comprehensive searches of published and unpublished literature identified 6571 studies which varied considerably in terms of their methodological approach and overall quality. Ten studies met the inclusion criteria. The synthesised findings indicated that, when compared to traditional CJS outcomes, CJLD services appeared to be effective in terms of identifying MDOs and impacting positively on criminal justice and mental health outcomes.Conclusions: Although the evidence may be deemed to be moderate in terms of methodological rigour, overall, the findings suggest that CJLD services can be beneficial. The effectiveness of services depends upon the model of service delivery, the availability of community services and the engagement of MDOs.The successful implementation of CJLD services requires a clearer recognition of the importance of system of care principles.
Resumo:
A leading theory hypothesizes that schizophrenia arises from dysregulation of the dopamine system in certain brain regions. As this dysregulation could arise from abnormal expression of D2 dopamine receptors, the D2 receptor gene (DRD2) on chromosome 11q is a candidate locus for schizophrenia. We tested whether allelic variation at DRD2 and five surrounding loci cosegregated with schizophrenia in 112 small- to moderate-size Irish families containing two or more members affected with schizophrenia or schizoaffective disorder, defined by DSM-III-R. Evidence of linkage was assessed using varying definitions of illness and modes of transmission. Assuming genetic homogeneity, linkage between schizophrenia and large regions of 11q around DRD2 could be strongly excluded. Assuming genetic heterogeneity, variation at the DRD2 locus could be rejected as a major risk factor for schizophrenia in more than 50% of these families for all models tested and in as few as 25% of the families for certain models. The DRD2 linkage in fewer than 25% of these families could not be excluded under any of the models tested. Our results suggest that the major component of genetic susceptibility to schizophrenia is not due to allelic variation at the DRD2 locus or other genes in the surrounding chromosomal region.
Resumo:
In our genome scan for schizophrenia genes in 265 Irish pedigrees, marker D5S818 in 5q22 produced the second best result of the first 223 markers tested (P = 0.002). We then tested an additional 13 markers and the evidence suggests the presence of a vulnerability locus for schizophrenia in region 5q22-31. This region appears to be distinct from those chromosome 5 regions studied in two prior reports, but the same as that producing positive results in the report by Wildenauer and colleagues found elsewhere in this issue. The largest pairwise heterogeneity LOD (H-LOD) score was found with marker D5S393 (max 3.04, P = 0.0005), assuming a narrow phenotypic category, and a genetic model with intermediate heterozygotic liability. In marked contrast to the H-LOD scores from our sample with markers from the regions of interest on chromosomes 6p and 8p, expanding the disease definition to include schizophrenia spectrum or nonspectrum disorders produced substantially smaller scores, with a number of markers failing to yield positive values at any recombination fraction. Using multipoint H-LODS, the strongest evidence for linkage occurs under the narrow phenotypic definition and recessive genetic model, with a peak at marker D5S804 (max 3.35, P = 0.0002). Multipoint nonparametric linkage analysis produced a peak in the same location (max z = 2.84, P = 0.002) with the narrow phenotypic definition. This putative vulnerability locus appears to be segregating in 10-25% of the families studied, but this estimate is tentative. Comparison of individual family multipoint H-LOD scores at the regions of interest on chromosomes 6p, 8p and 5q showed that only a minority of families yield high lod scores in two or three regions.