585 research outputs found

    Microstructural MRI basis of the cognitive functions in patients with Spinocerebellar ataxia type 2

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    Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disease involving the cerebellum. The particular atrophy pattern results in some typical clinical features mainly including motor deficits. In addition, the presence of cognitive impairments, involving language, visuospatial and executive functions, has been also shown in SCA2 patients and it is now widely accepted as a feature of the disease. The aim of the study is to investigate the microstructural patterns and the anatomo-functional substrate that could account for the cognitive symptomatology observed in SCA2 patients. In the present study, diffusion tensor imaging (DTI) based-tractography was performed to map the main cerebellar white matter (WM) bundles, such as Middle and Superior Cerebellar Peduncles, connecting cerebellum with higher order cerebral regions. Damage-related diffusivity measures were used to determine the pattern of pathological changes of cerebellar WM microstructure in patients affected by SCA2 and correlated with the patients' cognitive scores. Our results provide the first evidence that WM diffusivity is altered in the presence of the cerebellar cortical degeneration associated with SCA2 thus resulting in a cerebello-cerebral dysregulation that may account for the specificity of cognitive symptomatology observed in patients

    Neural substrates of motor and cognitive dysfunctions in SCA2 patients: a network based statistics analysis

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    Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disease characterized by a progressive cerebellar syndrome, which can be isolated or associated with extracerebellar signs. It has been shown that patients affected by SCA2 present also cognitive impairments and psychiatric symptoms. The cerebellum is known to modulate cortical activity and to contribute to distinct functional networks related to higher-level functions beyond motor control. It is therefore conceivable that one or more networks, rather than isolated regions, may be dysfunctional in cerebellar degenerative diseases and that an abnormal connectivity within specific cerebello-cortical regions might explain the widespread deficits typically observed in patients. In the present study, the network-based statistics (NBS) approach was used to assess differences in functional connectivity between specific cerebellar and erebral “nodes” in SCA2 patients. Altered inter-nodal connectivity was found between more posterior regions in the cerebellum and regions in the cerebral cortex clearly related to cognition and emotion. Furthermore, more anterior cerebellar lobules showed altered inter-nodal connectivity with motor and somatosensory cerebral regions. The present data suggest that in SCA2 a cerebellar dysfunction affects long-distance cerebral regions and that the clinical symptoms may be specifically related with connectivity changes between motor and non-motor cerebello-cortical nodes

    Functional changes of mentalizing network in SCA2 patients: novel insights into understanding the social cerebellum

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    In recent years, increasing evidence of the cerebellar role in social cognition has emerged. The cerebellum has been shown to modulate cortical activity of social brain regions serving as a regulator of function-specific mentalizing and mirroring processes. In particular, a mentalizing area in the posterior cerebellum, specifically Crus II, is preferentially recruited for more complex and abstract forms of social processing, together with mentalizing cerebral areas including the dorsal medial prefrontal cortex (dmPFC), the temporo-parietal junction (TPJ), and the precuneus. In the present study, the network-based statistics approach was used to assess functional connectivity (FC) differences within this mentalizing cerebello-cerebral network associated with a specific cerebellar damage. To this aim, patients affected by spinocerebellar ataxia type 2 (SCA2), a neurodegenerative disease specifically affecting regions of the cerebellar cortex, and age-matched healthy subjects have been enrolled. The dmPFC, left and right TPJ, the precuneus, and the cerebellar Crus II were used as regions of interest to construct the mentalizing network to be analyzed and evaluate pairwise functional relations between them. When compared with controls, SCA2 patients showed altered internodal connectivity between dmPFC, left (L-) and right (R-) TPJ, and right posterior cerebellar Crus II.The present results indicate that FC changes affect a function-specific mentalizing network in patients affected by cerebellar damage. In particular, they allow to better clarify functional alteration mechanisms driven by the cerebellar damage associated with SCA2 suggesting that selective cortico-cerebellar functional disconnections may underlie patients' social impairment in domain-specific complex and abstract forms of social functioning

    Penicillamine-related lichenoid dermatitis and utility of zinc acetate in a wilson disease patient with hepatic presentation, anxiety and spect abnormalities

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    Wilson disease is an autosomal recessive disorder of hepatic copper metabolism with consequent copper accumulation and toxicity in many tissues and consequent hepatic, neurologic and psychiatric disorders. We report a case of Wilson disease with chronic liver disease; moreover, in our patient, presenting also with high levels of state anxiety without depression, 99mTc-ECD- SPECT showed cortical hypoperfusion in frontal lobes, more marked on the left frontal lobe. During the follow-up of our patient, penicillamine was interrupted after the appearance of a lichenoid dermatitis, and zinc acetate permitted to continue the successful treatment of the patient without side-effects. In our case the therapy with zinc acetate represented an effective treatment for a Wilson disease patient in which penicillamine-related side effects appeared. The safety of the zinc acetate allowed us to avoid other potentially toxic chelating drugs; this observation is in line with the growing evidence on the efficacy of the drug in the treatment of Wilson disease. Since most of Wilson disease penicillamine-treated patients do not seem to develop this skin lesion, it could be conceivable that a specific genetic factor is involved in drug response. Further studies are needed for a better clarification of Wilson disease therapy, and in particular to differentiate specific therapies for different Wilson disease phenotypes

    Chemotherapy cardiotoxicity: cardioprotective drugs and early identification of cardiac dysfunction.

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    Background: Chemotherapy cardiotoxicity is an emerging problem and it is very important to prevent cardiac dysfunction caused by anticancer drugs. The aim of this study was to assess the alterations of the cardiac function induced by chemotherapy in a follow-up of 2 years and to evaluate the cardioprotective role of angiotensin-converting enzyme inhibitors (ACEIs) in the prevention of cardiac dysfunction. Methods: A prospective study was carried out using patients with breast cancer (85 women; median age 57W12years) and other inclusion and exclusion criteria. On the basis of treatment, patients were divided into six groups: fluorouracil-epirubicincyclophosphamide, FEC (group A); FEC and trastuzumab (B); trastuzumab (C); FEC and taxotere (D); FEC, paclitaxel and trastuzumab (E); and chemotherapy and cardioprotective drugs (F). Cardiological evaluation including electrocardiogram and conventional echocardiogram with tissue Doppler imaging (TDI) was carried out at T0 (before starting chemotherapy), T1 (after 6months from the start of chemotherapy) and T2 (2 years after the end of chemotherapy). Results: Significant changes in the TDI parameters of systolic and diastolic function were observed at T1 and T2 in all patients. A significant reduction of left ventricular ejection fraction (LVEF) was observed only at T2. In the patients treated with ACEI (F), these changes were less significant than in other groups and they do not have significant changes in the indices of diastolic function. Conclusion: TDI is more sensitive than conventional echocardiogram in the early diagnosis of cardiac dysfunction and ACEIs seem to have an important role in the prevention of cardiotoxicity

    On the merit of a Central Limit Theorem-based approximation in statistical physics

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    The applicability conditions of a recently reported Central Limit Theorem-based approximation method in statistical physics are investigated and rigorously determined. The failure of this method at low and intermediate temperature is proved as well as its inadequacy to disclose quantum criticalities at fixed temperatures. Its high temperature predictions are in addition shown to coincide with those stemming from straightforward appropriate expansions up to (k_B T)^(-2). Our results are clearly illustrated by comparing the exact and approximate temperature dependence of the free energy of some exemplary physical systems.Comment: 12 pages, 1 figur
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