412 research outputs found

    Autistic behavior in boys with fragile X syndrome: social approach and HPA-axis dysfunction

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    The primary goal of this study was to examine environmental and neuroendocrine factors that convey increased risk for elevated autistic behavior in boys with Fragile X syndrome (FXS). This study involves three related analyses: (1) examination of multiple dimensions of social approach behaviors and how they vary over time, (2) investigation of mean levels and modulation of salivary cortisol levels in response to social interaction, and (3) examination of the relationship of social approach and autistic behaviors to salivary cortisol. Poor social approach and elevated baseline and regulation cortisol are discernible traits that distinguish boys with FXS and ASD from boys with FXS only and from typically developing boys. In addition, blunted cortisol change is associated with increased severity of autistic behaviors only within the FXS and ASD group. Boys with FXS and ASD have distinct behavioral and neuroendocrine profiles that differentiate them from those with FXS alone and typically developing boys

    Open-label add-on treatment trial of minocycline in fragile X syndrome

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    <p>Abstract</p> <p>Background</p> <p>Fragile X syndrome (FXS) is a disorder characterized by a variety of disabilities, including cognitive deficits, attention-deficit/hyperactivity disorder, autism, and other socio-emotional problems. It is hypothesized that the absence of the fragile X mental retardation protein (FMRP) leads to higher levels of matrix metallo-proteinase-9 activity (MMP-9) in the brain. Minocycline inhibits MMP-9 activity, and alleviates behavioural and synapse abnormalities in <it>fmr1 </it>knockout mice, an established model for FXS. This open-label add-on pilot trial was conducted to evaluate safety and efficacy of minocycline in treating behavioural abnormalities that occur in humans with FXS.</p> <p>Methods</p> <p>Twenty individuals with FXS, ages 13-32, were randomly assigned to receive 100 mg or 200 mg of minocycline daily. Behavioural evaluations were made prior to treatment (baseline) and again 8 weeks after daily minocycline treatment. The primary outcome measure was the Aberrant Behaviour Checklist-Community Edition (ABC-C) Irritability Subscale, and the secondary outcome measures were the other ABC-C subscales, clinical global improvement scale (CGI), and the visual analog scale for behaviour (VAS). Side effects were assessed using an adverse events checklist, a complete blood count (CBC), hepatic and renal function tests, and antinuclear antibody screen (ANA), done at baseline and at 8 weeks.</p> <p>Results</p> <p>The ABC-C Irritability Subscale scores showed significant improvement (p < 0.001), as did the VAS (p = 0.003) and the CGI (p < 0.001). The only significant treatment-related side effects were minor diarrhea (n = 3) and seroconversion to a positive ANA (n = 2).</p> <p>Conclusions</p> <p>Results from this study demonstrate that minocycline provides significant functional benefits to FXS patients and that it is well-tolerated. These findings are consistent with the <it>fmr1 </it>knockout mouse model results, suggesting that minocycline modifies underlying neural defects that account for behavioural abnormalities. A placebo-controlled trial of minocycline in FXS is warranted.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Open-Label Trial NCT00858689.</p

    TTF-1 Action on the Transcriptional Regulation of Cyclooxygenase-2 Gene in the Rat Brain

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    We have recently found that thyroid transcription factor-1 (TTF-1), a homeodomain-containing transcription factor, is postnatally expressed in discrete areas of the hypothalamus and closely involved in neuroendocrine functions. We now report that transcription of cyclooxygenase-2 (COX-2), the rate limiting enzyme in prostaglandin biosynthesis, was inhibited by TTF-1. Double immunohistochemistry demonstrated that TTF-1 was expressed in the astrocytes and endothelial cells of blood vessel in the hypothalamus. Promoter assays and electrophoretic mobility shift assays showed that TTF-1 inhibited COX-2 transcription by binding to specific binding domains in the COX-2 promoter. Furthermore, blocking TTF-1 synthesis by intracerebroventricular injection of an antisense oligomer induced an increase of COX-2 synthesis in non-neuronal cells of the rat hypothalamus, and resulted in animals' hyperthermia. These results suggest that TTF-1 is physiologically involved in the control of thermogenesis by regulating COX-2 transcription in the brain

    Modulation of dendritic spine development and plasticity by BDNF and vesicular trafficking: fundamental roles in neurodevelopmental disorders associated with mental retardation and autism

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    The process of axonal and dendritic development establishes the synaptic circuitry of the central nervous system (CNS) and is the result of interactions between intrinsic molecular factors and the external environment. One growth factor that has a compelling function in neuronal development is the neurotrophin brain-derived neurotrophic factor (BDNF). BDNF participates in axonal and dendritic differentiation during embryonic stages of neuronal development, as well as in the formation and maturation of dendritic spines during postnatal development. Recent studies have also implicated vesicular trafficking of BDNF via secretory vesicles, and both secretory and endosomal trafficking of vesicles containing synaptic proteins, such as neurotransmitter and neurotrophin receptors, in the regulation of axonal and dendritic differentiation, and in dendritic spine morphogenesis. Several genes that are either mutated or deregulated in neurodevelopmental disorders associated with mental retardation have now been identified, and several mouse models of these disorders have been generated and characterized. Interestingly, abnormalities in dendritic and synaptic structure are consistently observed in human neurodevelopmental disorders associated with mental retardation, and in mouse models of these disorders as well. Abnormalities in dendritic and synaptic differentiation are thought to underlie altered synaptic function and network connectivity, thus contributing to the clinical outcome. Here, we review the roles of BDNF and vesicular trafficking in axonal and dendritic differentiation in the context of dendritic and axonal morphological impairments commonly observed in neurodevelopmental disorders associated with mental retardation

    Cold gas accretion in galaxies

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    Evidence for the accretion of cold gas in galaxies has been rapidly accumulating in the past years. HI observations of galaxies and their environment have brought to light new facts and phenomena which are evidence of ongoing or recent accretion: 1) A large number of galaxies are accompanied by gas-rich dwarfs or are surrounded by HI cloud complexes, tails and filaments. It may be regarded as direct evidence of cold gas accretion in the local universe. It is probably the same kind of phenomenon of material infall as the stellar streams observed in the halos of our galaxy and M31. 2) Considerable amounts of extra-planar HI have been found in nearby spiral galaxies. While a large fraction of this gas is produced by galactic fountains, it is likely that a part of it is of extragalactic origin. 3) Spirals are known to have extended and warped outer layers of HI. It is not clear how these have formed, and how and for how long the warps can be sustained. Gas infall has been proposed as the origin. 4) The majority of galactic disks are lopsided in their morphology as well as in their kinematics. Also here recent accretion has been advocated as a possible cause. In our view, accretion takes place both through the arrival and merging of gas-rich satellites and through gas infall from the intergalactic medium (IGM). The infall may have observable effects on the disk such as bursts of star formation and lopsidedness. We infer a mean ``visible'' accretion rate of cold gas in galaxies of at least 0.2 Msol/yr. In order to reach the accretion rates needed to sustain the observed star formation (~1 Msol/yr), additional infall of large amounts of gas from the IGM seems to be required.Comment: To appear in Astronomy & Astrophysics Reviews. 34 pages. Full-resolution version available at http://www.astron.nl/~oosterlo/accretionRevie

    Altered mRNA Editing and Expression of Ionotropic Glutamate Receptors after Kainic Acid Exposure in Cyclooxygenase-2 Deficient Mice

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    Kainic acid (KA) binds to the AMPA/KA receptors and induces seizures that result in inflammation, oxidative damage and neuronal death. We previously showed that cyclooxygenase-2 deficient (COX-2−/−) mice are more vulnerable to KA-induced excitotoxicity. Here, we investigated whether the increased susceptibility of COX-2−/− mice to KA is associated with altered mRNA expression and editing of glutamate receptors. The expression of AMPA GluR2, GluR3 and KA GluR6 was increased in vehicle-injected COX-2−/− mice compared to wild type (WT) mice in hippocampus and cortex, whereas gene expression of NMDA receptors was decreased. KA treatment decreased the expression of AMPA, KA and NMDA receptors in the hippocampus, with a significant effect in COX-2−/− mice. Furthermore, we analyzed RNA editing levels and found that the level of GluR3 R/G editing site was selectively increased in the hippocampus and decreased in the cortex in COX-2−/− compared with WT mice. After KA, GluR4 R/G editing site, flip form, was increased in the hippocampus of COX-2−/− mice. Treatment of WT mice with the COX-2 inhibitor celecoxib for two weeks decreased the expression of AMPA/KA and NMDAR subunits after KA, as observed in COX-2−/− mice. After KA exposure, COX-2−/− mice showed increased mRNA expression of markers of inflammation and oxidative stress, such as cytokines (TNF-α, IL-1β and IL-6), inducible nitric oxide synthase (iNOS), microglia (CD11b) and astrocyte (GFAP). Thus, COX-2 gene deletion can exacerbate the inflammatory response to KA. We suggest that COX-2 plays a role in attenuating glutamate excitotoxicity by modulating RNA editing of AMPA/KA and mRNA expression of all ionotropic glutamate receptor subunits and, in turn, neuronal excitability. These changes may contribute to the increased vulnerability of COX-2−/− mice to KA. The overstimulation of glutamate receptors as a consequence of COX-2 gene deletion suggests a functional coupling between COX-2 and the glutamatergic system

    Clinical significance of stromal apoptosis in colorectal cancer

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    BackgroundEpithelial and stromal cells play an important role in the development of colorectal cancer (CRC). We aimed to determine the prognostic significance of both epithelial and stromal cell apoptosis in CRC.MethodsTotal apoptosis was determined by caspase-3 activity measurements in protein homogenates of CRC specimens and adjacent normal mucosa of 211 CRC patients. Epithelial apoptosis was determined by an ELISA specific for a caspase-3-degraded cytokeratin 18 product, the M30 antigen. Stromal apoptosis was determined from the ratio between total and epithelial apoptosis.ResultsEpithelial and stromal apoptosis, as well as total apoptosis, were significantly higher in CRC compared with corresponding adjacent normal mucosa. Low total tumour apoptosis (&lt; or = median caspase-3 activity) was associated with a significantly worse disease recurrence (hazard ratio (HR), 95% confidence interval (95% CI): 1.77 (1.05-3.01)), independent of clinocopathological parameters. Epithelial apoptosis was not associated with clinical outcome. In contrast, low stromal apoptosis (&lt; or = median caspase-3/M30) was found to be an independent prognostic factor for overall survival, disease-free survival and disease recurrence, with HRs (95% CI) of 1.66 (1.17-2.35), 1.62 (1.15-2.29) and 1.69 (1.01-2.85), respectively.InterpretationStromal apoptosis, in contrast to epithelial apoptosis, is an important factor with respect to survival and disease-recurrence in CRC

    Visual attention and autistic behavior in infants with fragile X syndrome

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    Fragile X syndrome (FXS) is the leading known inherited cause of intellectual disability and the most common known biological cause of autism. Approximately 25% to 50% of males with FXS meet full diagnostic criteria for autism. Despite the high comorbidity between FXS and autism and the ability to diagnose FXS prenatally or at birth, no studies have examined indicators of autism in infants with FXS. The current study focused on indices of visual attention, one of the earliest and most robust behavioral indicators of autism in idiopathic (non-FXS) autism. Analyses revealed lower HR variability, shallower HR decelerations, and prolonged look durations in 12-month old infants with FXS that were correlated with severity of autistic behavior but not mental age
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