Sox1-deficient mice suffer from epilepsy associated with abnormal ventral forebrain development and olfactory cortex hyperexcitability

Mutations in several classes of embryonically-expressed transcription factor genes are associated with behavioral disorders and epilepsies. However, there is little known about how such genetic and neurodevelopmental defects lead to brain dysfunction. Here we present the characterization of an epilepsy syndrome caused by the absence of the transcription factor SOX1 in mice. In vivo electroencephalographic recordings from SOX1 mutants established a correlation between behavioral changes and cortical output that was consistent with a seizure origin in the limbic forebrain. In vitro intracellular recordings from three major forebrain regions, neocortex, hippocampus and olfactory (piriform) cortex (OC) showed that only the OC exhibits abnormal enhanced synaptic excitability and spontaneous epileptiform discharges. Furthermore, the hyperexcitability of the OC neurons was present in mutants prior to the onset of seizures but was completely absent from both the hippocampus and neocortex of the same animals. The local inhibitory GABAergic neurotransmission remained normal in the OC of SOX1-deficient brains, but there was a severe developmental deficit of OC postsynaptic target neurons, mainly GABAergic projection neurons within the olfactory tubercle and the nucleus accumbens shell. Our data show that SOX1 is essential for ventral telencephalic development and suggest that the neurodevelopmental defect disrupts local neuronal circuits leading to epilepsy in the SOX1-deficient mice

What have we learnt about heavy carbenes through laser flash photolysis studies?

Time resolved gas-phase kinetic studies have contributed a great deal of fundamental information about the reactions and reactivity of heavy carbenes (silylenes, germylenes and stannylenes) during the past two decades. In this article we trace the development of our understanding through the mechanistic themes of intermediate complexes, third body assisted associations, catalysed reactions, non-observed reactions and substituent effects. Ab initio (quantum chemical) calculations have substantially assisted mechanistic interpretation and are discussed where appropriate. Trends in reactivity are identified and some signposts to future studies are indicated. This review, although detailed, is not comprehensive.

Under-investigation of older people with abnormal chest radiographs

Background: Whilst many authors have previously suggested that older people are under-represented in the investigation and management of lung cancer, few data are available as to the effect of age on the subsequent investigation and management of a patient with an abnormal chest radiograph. Methods: During a 3-month period in a university teaching hospital, all abnormal chest radiographs suggestive of a possible diagnosis of lung cancer were identified, and patients subsequently followed to determine investigation, management and date of death over a 5-year period. Results: Thirty-seven younger (less than or equal to69 years, median age 62 years) and 43 older patients ( 670 years, median age 80 years) were identified. Of the 80 patients with a possible bronchial carcinoma only 59% had a further chest radiograph performed. Bronchoscopy was performed in 34% of patients, but a biopsy of the lesion was undertaken in only 24% of patients. Sixteen of the 80 patients, irrespective of what investigations had been undertaken, were referred for an oncological or surgical opinion. During the study period ( 3 months), 24% of the patients died. At 6, 24 and 60 months, respectively, the total deaths were 40, 78 and 88%. Conclusion: Older patients compared with those aged less than 70 years were less likely to be investigated, further, were more likely to be managed differently (i.e., less aggressively) and more likely to die within each time interval. In more of the older group a presumed death certificate diagnosis of pneumonia was made. When an abnormal chest radiograph raises the possibility of an underlying bronchial carcinoma, the finding of this study suggests that an ageist attitude influences the subsequent management of some patients. Copyright (C) 2005 S. Karger AG, Basel.

Mind-reading difficulties in the siblings of people with Asperger's syndrome: evidence for a genetic influence in the abnormal development of a specific cognitive domain

Background: Previous research suggests that the phenotype associated with Asperger's syndrome (AS) includes difficulties in understanding the mental states of others, leading to difficulties in social communication and social relationships. It has also been suggested that the first-degree relatives of those with AS can demonstrate similar difficulties, albeit to a lesser extent. This study examined 'theory of mind' (ToM) abilities in the siblings of children with AS relative to a matched control group. Method: 2 7 children who had a sibling with AS were administered the children's version of the 'Eyes Test'(Baron-Cohen, Wheelwright, Stone, & Rutherford, 1999). The control group consisted of 27 children matched for age, sex, and a measure of verbal comprehension, and who did not have a family history of AS/autism. Results: A significant difference was found between the groups on the Eyes Test, the 'siblings' group showing a poorer performance on this measure of social cognition. The difference was more pronounced among female siblings. Discussion: These results are discussed in terms of the familial distribution of a neuro-cognitive profile associated with AS, which confers varying degrees of social handicap amongst first-degree relatives. The implication of this finding with regard to the autism/AS phenotype is explored, with some discussion of why this neuro-cognitive profile (in combination with corresponding strengths) may have an evolutionary imperative.

Whole-brain functional connectivity during emotional word classification in medication-free Major Depressive Disorder: abnormal salience circuitry and relations to positive emotionality

Major Depressive Disorder (MDD) has been associated with biased processing and abnormal regulation of negative and positive information, which may result from compromised coordinated activity of prefrontal and subcortical brain regions involved in evaluating emotional information. We tested whether patients with MDD show distributed changes in functional connectivity with a set of independently derived brain networks that have shown high correspondence with different task demands, including stimulus salience and emotional processing. We further explored if connectivity during emotional word processing related to the tendency to engage in positive or negative emotional states. In this study, 25 medication-free MDD patients without current or past comorbidity and matched controls (n=25) performed an emotional word-evaluation task during functional MRI. Using a dual regression approach, individual spatial connectivity maps representing each subject’s connectivity with each standard network were used to evaluate between-group differences and effects of positive and negative emotionality (extraversion and neuroticism, respectively, as measured with the NEO-FFI). Results showed decreased functional connectivity of the medial prefrontal cortex, ventrolateral prefrontal cortex, and ventral striatum with the fronto-opercular salience network in MDD patients compared to controls. In patients, abnormal connectivity was related to extraversion, but not neuroticism. These results confirm the hypothesis of a relative (para)limbic-cortical decoupling that may explain dysregulated affect in MDD. As connectivity of these regions with the salience network was related to extraversion, but not to general depression severity or negative emotionality, dysfunction of this network may be responsible for the failure to sustain engagement in rewarding behavior.

Abnormal functional activation and maturation of fronto-striato-temporal and cerebellar regions during sustained attention in autism spectrum disorder

Objective Sustained attention problems are common in people with autism spectrum disorder (ASD) and may have significant implications for the diagnosis and management of ASD and associated comorbidities. Furthermore, ASD has been associated with atypical structural brain development. The authors used functional MRI to investigate the functional brain maturation of attention between childhood and adulthood in people with ASD. Method Using a parametrically modulated sustained attention/vigilance task, the authors examined brain activation and its linear correlation with age between childhood and adulthood in 46 healthy male adolescents and adults (ages 11–35 years) with ASD and 44 age- and IQ-matched typically developing comparison subjects. Results Relative to the comparison group, the ASD group had significantly poorer task performance and significantly lower activation in inferior prefrontal cortical, medial prefrontal cortical, striato-thalamic, and lateral cerebellar regions. A conjunction analysis of this analysis with group differences in brain-age correlations showed that the comparison group, but not the ASD group, had significantly progressively increased activation with age in these regions between childhood and adulthood, suggesting abnormal functional brain maturation in ASD. Several regions that showed both abnormal activation and functional maturation were associated with poorer task performance and clinical measures of ASD and inattention. Conclusions The results provide first evidence that abnormalities in sustained attention networks in individuals with ASD are associated with underlying abnormalities in the functional brain maturation of these networks between late childhood and adulthood.

Detecting abnormal and collusive bids in capped tendering

Recent developments in the area of Bid Tender Forecasting have enabled bidders to implement new types of easy-to-use tools for increasing their chances of winning contracts. Although these new tools (such as iso-Score Curve Graphs, Scoring Probability Graphs, and Position Probability Graphs) are designed for bidders in capped tendering (tenders with an upper price limit), some of their principles can also be applied by a Contracting Authority to detect which bidders do not follow a standard pattern, that is, their bids are extremely high or low. Since a collusive bid generally needs to be sufficiently high or low to make an impact on the bid distribution, any person in charge of supervising capped tenders can be alerted to any bidder that might be involved in a cartel after identifying the same abnormal behavior in a series of tenders through simple calculations and a new type of graph.

Quick abnormal-bid-detection method for construction contract auctions

Noncompetitive bids have recently become a major concern in both public and private sector construction contract auctions. Consequently, several models have been developed to help identify bidders potentially involved in collusive practices. However, most of these models require complex calculations and extensive information that is difficult to obtain. The aim of this paper is to utilize recent developments for detecting abnormal bids in capped auctions (auctions with an upper bid limit set by the auctioner) and extend them to the more conventional uncapped auctions (where no such limits are set). To accomplish this, a new method is developed for estimating the values of bid distribution supports by using the solution to what has become known as the German Tank problem. The model is then demonstrated and tested on a sample of real construction bid data, and shown to detect cover bids with high accuracy. This paper contributes to an improved understanding of abnormal bid behavior as an aid to detecting and monitoring potential collusive bid practices.

Abnormal Corpus Callosum Integrity in Bipolar Disorder: A Diffusion Tensor Imaging Study

Objective: Abnormalities in the anterior interhemispheric connections provided by the corpus callosum (CC) have long been implicated in bipolar disorder (BID). In this study, we used complementary diffusion tensor imaging methods to study the structural integrity of the CC and localization of potential abnormalities in BD. Methods: Subjects included 33 participants with BID and 40 healthy comparison participants. Fractional anisotropy (FA) measures were compared between groups with region of interest (ROD methods to investigate the anterior, middle, and posterior CC and voxel-based methods to further localize abnormalities. Results: In ROI-based analyses, FA was significantly decreased in the anterior and middle CC in the BID group (p <.05). Voxel-based analyses similarly localized group differences to the genu, rostral body, and anterior midbody of CC (p <.05, corrected). Conclusion: The findings demonstrate abnormalities in the structural integrity of the anterior CC in BID that might contribute to altered interhemispheric connectivity in this disorder.

Abnormal anterior cingulum integrity in bipolar disorder determined through diffusion tensor imaging

Background Convergent evidence implicates white matter abnormalities in bipolar disorder. The cingulum is an important candidate structure for study in bipolar disorder as it provides substantial white matter connections within the corticolimbic neural system that subserves emotional regulation involved in the disorder. Aims To test the hypothesis that bipolar disorder is associated with abnormal white matter integrity in the cingulum. Method Fractional anisotropy in the anterior and posterior cingulum was compared between 42 participants with bipolar disorder and 42 healthy participants using diffusion tensor imaging. Results Fractional anisotropy was significantly decreased in the anterior cingulum in the bipolar disorder group compared with the healthy group (P=0.003); however, fractional anisotropy in the posterior cingulum did not differ significantly between groups. Conclusions Our findings demonstrate abnormalities in the structural integrity of the anterior cingulum in bipolar disorder. They extend evidence that supports involvement of the neural system comprising the anterior cingulate cortex and its corticolimbic gray matter connection sites in bipolar disorder to implicate abnormalities in the white matter connections within the system provided by the cingulum.

Detecting patterns of the spinoff decision of companies and accessing the determination of the abnormal returns

This paper examines value created through spinoffs over a period from 2002-2010. The net debt to average share price ratio and the debt to asset ratio of a company impacts the decision for this restructuring process statistically significant. The announcement of a spinoff yields abnormal returns (AR) for the stockholders of the parent. The relative size of the spin and the financial leverage correlated with the AR positively, whereas the net debt per share and the return on asset negatively. Therefore, no direct wealth transfer from the debt holders of a company to the equity holders can be derived from these results.

Do insiders get abnormal returns? : event studies on the trades of insiders of the firms with differentiated corporate governance of the São Paulo stock exchange

The subject insider trading is controversial. This paper presents series of event studies carried through on the trades with stocks of the firm carried by insiders with the objective to detect abnormal returns, based on the access to privileged information. The sample is composed by trades performed by insiders of the companies with stocks negotiated in the São Paulo Stock Exchange, that are classified as firms with differentiated corporate governance. Indication that trades performed by insiders resulted in abnormal returns compared to the statistically significant expected ones, as in the purchases of common shares; or for selling of preferred stocks.