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The striatum, comprising the caudate nucleus, putamen and nucleus accumbens, occupies a strategic location within cortico-striato-pallido-thalamic-cortical (corticostriatal) re-entrant neural circuits. Striatal neurodevelopment is precisely determined by phylogenetically conserved homeobox genes. Consisting primarily of medium spiny neurons, the striatum is strictly topographically organized based on cortical afferents and efferents. Particular corticostriatal neural circuits are considered to subserve certain domains of cognition, emotion and behaviour. Thus, the striatum may serve as a map of structural change in the cortical afferent pathways owing to deafferentation or neuroplasticity, and conversely, structural change in the striatum per se may structurally disrupt corticostriatal pathways. The morphology of the striatum may be quantified in vivo using advanced magnetic resonance imaging, as may cognitive functioning pertaining to corticostriatal circuits. It is proposed that striatal morphology may be a biomarker in neurodegenerative disease and potentially the basis of an endophenotype. [ABSTRACT FROM AUTHOR]

Background and purpose: Niemann-Pick disease type C (NPC) is a progressive neurovisceral disorder associated with dystonia, ataxia and a characteristic gaze palsy. Neuropathological studies have demonstrated brainstem atrophy associated with neuronal inclusions and loss, and neurofibrillary tangles, although it is not known whether this pathology can be detected in vivo or how these changes relate to illness variables, particularly ocular-motor changes. Our aim was to utilize a method for brainstem atrophy, validated in progressive supranuclear palsy (PSP), in a group of adult patients with NPC, and explore its relationship to illness variables and ocular-motor functioning. Methods: We calculated the midbrain and pontine area, and pontine-to-midbrain ratio (PMR) from midsagittal images of 10 adult patients with NPC and 27 age- and gender-matched controls. Measures were correlated with illness variables, and measures of horizontal saccadic functioning. Results: Pontine-to-midbrain ratio was 14% higher in the NPC group, but this difference was not significant. However, PMR showed a significant positive correlation with duration of illness and a measure of illness severity. Furthermore, PMR was significantly negatively correlated with saccadic peak velocity and gain, and self-paced saccadic performance. Conclusions: Pontine-to-midbrain ratio was increased in adult patients with NPC compared to controls, although not to the same degree as previously described in PSP, which also presents with significant gaze palsy. These changes were driven predominantly by progressive midbrain atrophy. The strong correlation with illness and ocular-motor variables suggests that it may be a useful marker for illness progression in NPC. [ABSTRACT FROM AUTHOR]

Hippocampal pathology is central to Alzheimer's disease (AD) and other forms of dementia such as frontotemporal lobar degeneration (FTLD). Autopsy studies have shown that certain hippocampal subfields are more vulnerable than others to AD and FTLD pathology, in particular the subiculum and cornu ammonis 1 (CA1). We conducted shape analysis of hippocampi segmented from structural T1 MRI images on clinically diagnosed dementia patients and controls. The subjects included 19 AD and 35 FTLD patients [13 frontotemporal dementia (FTD), 13 semantic dementia (SD), and 9 progressive nonfluent aphasia (PNFA)] and 21 controls. Compared to controls, SD displayed severe atrophy of the whole left hippocampus. PNFA and FTD also displayed atrophy on the left side, restricted to the hippocampal head in FTD. Finally, AD displayed most atrophy in left hippocampal body with relative sparing of the hippocampal head. Consistent with neuropathological studies, most atrophic deformation was found in CA1 and subiculum areas in FTLD and AD. [ABSTRACT FROM AUTHOR]

Background/Aims: Only a limited number of cognitive screening tools are available for the Persian-speaking population, and we sought to translate and validate the Neuropsychiatry Unit Cognitive Assessment Tool (NUCOG), a multidimensional cognitive screening tool. Methods: We used multiple language specialists to translate and then back-translate the NUCOG, and administered the Persian language NUCOG and Mini-Mental State Examination (MMSE) to 184 individuals: 60 controls and 124 patients, 33 of whom had dementia, 30 non-dementing neurological disorders and 61 a psychiatric illness. Results: The NUCOG outperformed the MMSE in differentiating the patient groups and controls. The ‘profile’ across the 5 NUCOG domains differentiated dementia subgroups such as senile dementia of the Alzheimer type (SDAT), frontotemporal dementia and mild cognitive impairment (MCI). Psychiatric patients with psychosis and posttraumatic stress disorder were more impaired than patients with affective disorders. The NUCOG reliably differentiated controls from patients with MCI (at 86.5/100, sensitivity of 83.3% and specificity of 87.5%) and SDAT (at 75/100, sensitivity and specificity of 100%) patients from controls. Conclusions: The Persian language NUCOG appears to perform strongly in an unselected population, reliably differentiating patients with dementia from controls, and detecting cognitive impairment in a range of clinical disorders. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

We describe the differential presentation of schizophrenia-like psychosis in two siblings with the 'variant' biochemical presentation of adult Niemann-Pick disease type C. The male sibling presented with psychosis at age 16 years and cognitive and motor disturbance at age 25 years, whereas his elder sister, sharing the same mutation but showing less severe biochemical, neuroimaging and ocular motor parameters, presented with a similar schizophrenia-like illness with associated cognitive and motor disturbance at age 31 years. Their illness onset, course and response to treatment mirrors the sex dimorphism seen in schizophrenia, and is suggestive of an interaction between the neurobiology of their metabolic disorder and sex differences in neurodevelopment. [ABSTRACT FROM AUTHOR]

High-strength automotive components are often made of AlSi7-based alloys. A very challenging problem with aluminium casting is the influence of melt flow during solidification, because it affects the microstructure formation and therefore the material properties. The scope of this paper is to investigate the effect of forced melt flow on the evolution of the dendritic microstructure in a binary AlSi7 alloy during directional solidification. Global modelling using the software CrysMAS provides typical flow patterns and velocities. These values are used as boundary condition for the flow in the phase field code MICRESS, which allows the numerical simulation of dendritic array solidification in 2D with applied flow. From solidification experiments in a gradient furnace with applied rotating magnetic field the dendrite shapes are determined. It is found consistently that intense melt flow leads to asymmetric dendrite shapes and the growth behaviour of the dendrite arms is directly correlated with the flow direction. [ABSTRACT FROM AUTHOR]

Background: Few studies have investigated the relationship between schizophrenia and frontotemporal dementia.Aims: To investigate this relationship through a clinicopathological investigation of young-onset frontotemporal dementia and a review of the case literature.Method: Cases of young-onset frontotemporal dementia were identified within the local brain bank. The clinical course and pathological findings were collated. For the literature review, cases of frontotemporal dementia identified through Medline were selected according to defined criteria. The demographic, clinical, pathological and genetic characteristics of cases presenting with a psychotic illness were identified.Results: In the case series, 5 of 17 patients with frontotemporal dementia had presented with a psychotic illness (schizophrenia/schizoaffective disorder n=4, bipolar disorder n=1) an average of 5 years prior to the dementia diagnosis. Patients with schizophrenia exhibited changes consistent with TDP-43 and ubiquitin-positive frontotemporal dementia. In the cases review, a third of patients aged 30 years or under and a quarter of those aged 40 years or under had been diagnosed with psychosis at presentation.Conclusions: Patients with young-onset frontotemporal dementia may be diagnosed with a psychotic illness years before the dementia diagnosis is made. These findings have implications for clinicians and for our further understanding of the neurobiology of psychotic illness. [ABSTRACT FROM AUTHOR]

Hashimoto's encephalopathy is a term used to describe an encephalopathy of presumed autoimmune origin characterised by high titres of antithyroid peroxidase antibodies. In a similar fashion to autoimmune thyroid disease, Hashimoto's encephalopathy is more common in women than in men. It has been reported in paediatric, adult and elderly populations throughout the world. The clinical presentation may involve a relapsing and remitting course and include seizures, stroke-like episodes, cognitive decline, neuropsychiatric symptoms and myoclonus. Thyroid function is usually clinically and biochemically normal.Hashimoto's encephalopathy appears to be a rare disorder, but, as it is responsive to treatment with corticosteroids, it must be considered in cases of 'investigation negative encephalopathies'. Diagnosis is made in the first instance by excluding other toxic, metabolic and infectious causes of encephalopathy with neuroimaging and CSF examination. Neuroimaging findings are often not helpful in clarifying the diagnosis. Common differential diagnoses when these conditions are excluded are Creutzfeldt-Jakob disease, rapidly progressive dementias, and paraneoplastic and nonparaneoplastic limbic encephalitis. In the context of the typical clinical picture, high titres of antithyroid antibodies, in particular antithyroid peroxidase antibodies, are diagnostic. These antibodies, however, can be detected in elevated titres in the healthy general population. Treatment with corticosteroids is almost always successful, although relapse may occur if this treatment is ceased abruptly. Other forms of immunomodulation, such as intravenous immune-globulin and plasma exchange, may also be effective. Despite the link to autoimmune thyroid disease, the aetiology of Hashimoto's encephalopathy is unknown. It is likely that antithyroid antibodies are not pathogenic, but titres can be a marker of treatment response. Pathological findings can suggest an inflammatory process, but features of a severe vasculitis are often absent. The links between the clinical pictures, thyroid disease, auto-antibody pattern and brain pathology await further clarification through research. It may be that Hashimoto's encephalopathy will be subsumed into a group of nonvasculitic autoimmune inflammatory meningoencephalopathies. This group may include disorders such as limbic encephalitis associated with voltage-gated potassium channel antibodies. Some authors have suggested abandoning any link to Hashimoto and renaming the condition 'steroid responsive encephalopathy associated with autoimmune thyroiditis' to better reflect current, if limited, understanding of this condition. [ABSTRACT FROM AUTHOR]

Conversion electron Mössbauer spectroscopy (CEMS) has been applied to the study of the metastable c-FeSi phase (i.e. an iron silicide with CsCl lattice structure) that was synthesized by implantation of Si + ions of 50 keV in energy into α-Fe (95% 57 Fe) near room temperature with a nominal dose of 5 × 10 17 cm -2 , and by molecular beam epitaxy (MBE). Iron silicide layers with different stoichiometry (FeSi 0.85 , FeSi, Fe 0.85 Si) were grown by codeposition of 57 Fe and Si onto an Fe buffer layer on MgO(100). For all FeSi layers the defective CsCl structure was observed after annealing at different temperatures. X-ray diffraction measurements were performed to determine the structure and epitaxial relationship of the c-FeSi films. The lattice parameter perpendicular to the film plane was found to be 2.77(5) Å. CEMS measurements revealed a lower than cubic site symmetry of the iron atoms for both the c-FeSi layers synthesized by ion implantation and by MBE. The formation of nearly undistorted c-FeSi after annealing is favored by excess Fe atoms in the deposited film. [ABSTRACT FROM AUTHOR]

Si+ ions of 50 keV in energy were implanted into α-Fe (95% 57Fe) with a nominal dose of 5 × 1017 cm−2 at 350°C. The depth distribution of the Fe-Si phases formed by ion implantation after annealing at 300 and 400°C for 1 h was studied quantitatively by depth-selective conversion-electron Mössbauer spectroscopy (DCEMS). Ordered Fe3Si and ε-FeSi was observed. [ABSTRACT FROM AUTHOR]

The depth distribution of the iron disilicide phases (α-FeSi[sub 2] and β-FeSi[sub 2]) was investigated nondestructively by depth-selective conversion-electron Mo¨ssbauer spectroscopy after Fe[sup +] implantation (200 keV, 3x10[sup 17] cm-2) and after subsequent rapid thermal annealing (RTA) at 900 °C for 30 s. The depth profiles of the two phases were found to be correlated with the Fe concentration profiles as determined by Auger electron sputter depth profiling. For the as-implanted state a broad distribution of a phase mixture of α- and β-FeSi[sub 2] is observed. Subsequent RTA induces a layered structure including a buried β-FeSi[sub 2] layer with a high phase content of 90% near 220 nm. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]