340 research outputs found

    Got Sulfate? Luring Axons This Way and That

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    Glycosaminoglycans are sulfated in complex and changing patterns that affect neural development. These sugars mediate interactions between macromolecules, and their biological contributions are of high interest. In this issue of Chemistry & Biology, Shipp and Hsieh-Wilson [1] describe microarrays to probe these complex modifications

    Aggrecan is required for growth plate cytoarchitecture and differentiation

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    AbstractThe proteoglycan aggrecan is a prominent component of the extracellular matrix in growth plate cartilage. A naturally occurring, recessive, perinatally lethal mutation in the aggrecan core protein gene, cmdbc (Acancmd-Bc), that deletes the entire protein-coding sequence provided a model in which to characterize the phenotypic and morphologic effects of aggrecan deletion on skeletal development. We also generated a novel transgenic mouse, Tg(COL2A1-ACAN), that has the chick ACAN coding sequence driven by the mouse COL2A1 promoter to enable the production of cmdbc/cmdbc; Tg(COL2A1-ACAN) rescue embryos. These were used to assess the impact of aggrecan on growth plate organization, chondrocyte survival and proliferation, and the expression of mRNAs encoding chondrocyte differentiation markers and growth factors. Homozygous mutant (cmdbc/cmdbc) embryos exhibited severe defects in all skeletal elements with deformed and shortened (50%) limb elements. Expression of aggrecan in rescue embryos reversed the skeletal defects to varying degrees with a 20% increase in limb element length and near-full reversal (80%) of size and diameter of the ribcage and vertebrae. Aggrecan-null growth plates were devoid of matrix and lacked chondrocyte organization and differentiation, while those of the rescue embryos exhibited matrix production concomitant with partial zonation of chondrocytes having proliferative and hypertrophic morphologies. Deformation of the trachea, likely the cause of the mutation׳s lethality, was reduced in the rescue embryos. Aggrecan-null embryos also had abnormal patterns of COL10A1, SOX9, IHH, PTCH1, and FGFR3 mRNA expression in the growth plate. Expression of chick aggrecan in the rescue embryos notably increased COLX expression, accompanied by the reappearance of a hypertrophic zone and IHH expression. Significantly, in transgenic rescue embryos, the cell death and decreased proliferation phenotypes exhibited by the mutants were reversed; both were restored to wild-type levels. These findings suggest that aggrecan has a major role in regulating the expression of key growth factors and signaling molecules during development of cartilaginous tissue and is essential for proper chondrocyte organization, morphology, and survival during embryonic limb development

    Using gene expression data to identify certain gastro-intestinal diseases

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    BACKGROUND: Inflammatory bowel diseases, ulcerative colitis and Crohn’s disease are considered to be of autoimmune origin, but the etiology of irritable bowel syndrome remains elusive. Furthermore, classifying patients into irritable bowel syndrome and inflammatory bowel diseases can be difficult without invasive testing and holds important treatment implications. Our aim was to assess the ability of gene expression profiling in blood to differentiate among these subject groups. METHODS: Transcript levels of a total of 45 genes in blood were determined by quantitative real-time polymerase chain reaction (RT-PCR). We applied three separate analytic approaches; one utilized a scoring system derived from combinations of ratios of expression levels of two genes and two different support vector machines. RESULTS: All methods discriminated different subject cohorts, irritable bowel syndrome from control, inflammatory bowel disease from control, irritable bowel syndrome from inflammatory bowel disease, and ulcerative colitis from Crohn’s disease, with high degrees of sensitivity and specificity. CONCLUSIONS: These results suggest these approaches may provide clinically useful prediction of the presence of these gastro-intestinal diseases and syndromes

    Variations in Hip Shape Are Associated with Radiographic Knee Osteoarthritis : Cross-sectional and Longitudinal Analyses of the Johnston County Osteoarthritis Project

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    Acknowledgment We thank our funding sources, as well as the staff and participants in the Johnston County Osteoarthritis Project, without whom this work would not be possible. Funding was provided in part by the US National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) K23 AR061406 (Nelson); US National Institutes of Health (NIH)/NIAMS P60AR30701 (Jordan/Renner/Schwartz); US Centers for Disease Control/Association of Schools of Public Health S043 and S3486 (Jordan/Renner); K24-AR04884, P50-AR063043, and P50-AR060752 (Lane); and NIH/National Center for Advancing Translational Sciences KL2TR001109 (Golightly).Peer reviewedPostprin

    Profiles of HIV care disruptions among adult patients lost to follow-up in Zambia: A latent class analysis

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    BACKGROUND: Patients report varied barriers to HIV care across multiple domains, but specific barrier patterns may be driven by underlying, but unobserved, behavioral profiles. METHODS: We traced a probability sample of patients lost to follow-up (\u3e90 days late) as of July 31, 2015 from 64 clinics in Zambia. Among those found alive, we ascertained patient-reported reasons for care disruptions. We performed latent class analysis to identify patient subgroups with similar patterns of reasons reported and assessed the association between class membership and care status (ie, disengaged versus silently transferred to a new site). RESULTS: Among 547 patients, we identified 5 profiles of care disruptions: (1) Livelihood and Mobility (30.6% of the population) reported work/school obligations and mobility/travel as reasons for care disruptions; (2) Clinic Accessibility (28.9%) reported challenges with attending clinic; (3) Mobility and Family (21.9%) reported family obligations, mobility/travel, and transport-related reasons; (4) Doubting Need for HIV care (10.2%) reported uncertainty around HIV status or need for clinical care, and (5) Multidimensional Barriers to Care (8.3%) reported numerous (mean 5.6) reasons across multiple domains. Patient profiles were significantly associated with care status. The Doubting Need for HIV Care class were mostly disengaged (97.9%), followed by the Multidimensional Barriers to Care (62.8%), Clinic Accessibility (62.4%), Livelihood and Mobility (43.6%), and Mobility and Family (23.5%) classes. CONCLUSION: There are distinct HIV care disruption profiles that are strongly associated with patients\u27 current engagement status. Interventions targeting these unique profiles may enable more effective and tailored strategies for improving HIV treatment outcomes

    Depression in stroke rehabilitation

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    Despite recent advances in understanding the pathophysiology of poststroke depression, major questions remain. They include the relative importance of lesion location and size and the confounding effects of time since stroke, age, prior history of depression, and cerebral atrophy. To evaluate these issues, we systematically assessed depressive features, functional status, and brain structure with computer tomography scans in 91 men undergoing stroke rehabilitation. Forty percent met DSM-III criteria for major depressive disorder. Mood disturbance was more severe for patients with right than with left hemisphere lesions, correlated with functional disability and lesion size, and was associated with previous history of depression. Age, time since stroke, and atrophy did not correlate with mood. Depression is common in delayed stroke recovery, regardless of lesion location. Because there are no demographic or anatomic features that predict the absence of depression, depression screening should be part of the assessment of all patients undergoing stroke rehabilitation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30792/1/0000446.pd

    Incident symptomatic hip osteoarthritis is associated with differences in hip shape by active shape modeling: The Johnston County Osteoarthritis Project

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    To investigate hip shape by active shape modeling (ASM) as a potential predictor of incident radiographic and symptomatic hip OA (rHOA and srHOA)

    Vitamin D supplementation and breast cancer prevention : a systematic review and meta-analysis of randomized clinical trials

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    In recent years, the scientific evidence linking vitamin D status or supplementation to breast cancer has grown notably. To investigate the role of vitamin D supplementation on breast cancer incidence, we conducted a systematic review and meta-analysis of randomized controlled trials comparing vitamin D with placebo or no treatment. We used OVID to search MEDLINE (R), EMBASE and CENTRAL until April 2012. We screened the reference lists of included studies and used the “Related Article” feature in PubMed to identify additional articles. No language restrictions were applied. Two reviewers independently extracted data on methodological quality, participants, intervention, comparison and outcomes. Risk Ratios and 95% Confident Intervals for breast cancer were pooled using a random-effects model. Heterogeneity was assessed using the I2 test. In sensitivity analysis, we assessed the impact of vitamin D dosage and mode of administration on treatment effects. Only two randomized controlled trials fulfilled the pre-set inclusion criteria. The pooled analysis included 5372 postmenopausal women. Overall, Risk Ratios and 95% Confident Intervals were 1.11 and 0.74–1.68. We found no evidence of heterogeneity. Neither vitamin D dosage nor mode of administration significantly affected breast cancer risk. However, treatment efficacy was somewhat greater when vitamin D was administered at the highest dosage and in combination with calcium (Risk Ratio 0.58, 95% Confident Interval 0.23–1.47 and Risk Ratio 0.93, 95% Confident Interval 0.54–1.60, respectively). In conclusions, vitamin D use seems not to be associated with a reduced risk of breast cancer development in postmenopausal women. However, the available evidence is still limited and inadequate to draw firm conclusions. Study protocol code: FARM8L2B5L

    A genomic rearrangement resulting in a tandem duplication is associated with split hand-split foot malformation 3 (SHFM3) at 10q24

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    Split hand-split foot malformation (SHFM) is characterized by hypoplasia/aplasia of the central digits with fusion of the remaining digits. SHFM is usually an autosomal dominant condition and at least five loci have been identified in humans. Mutation analysis of the DACTYLIN gene, suspected to be responsible for SHFM3 in chromosome 10q24, was conducted in seven SHFM patients. We screened the coding region of DACTYLIN by single-strand conformation polymorphism and sequencing, and found no point mutations. However, Southern, pulsed field gel electrophoresis and dosage analyses demonstrated a complex rearrangement associated with a ∼0.5 Mb tandem duplication in all the patients. The distal and proximal breakpoints were within an 80 and 130 kb region, respectively. This duplicated region contained a disrupted extra copy of the DACTYLIN gene and the entire LBX1 and β-TRCP genes, known to be involved in limb development. The possible role of these genes in the SHFM3 phenotype is discusse
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