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  • 1
    ISSN: 1619-7089
    Keywords: Head injury Single-photon emission tomography Nigrostriatal dysfunction Striatal dopamine transporter Striatal D2 receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Structural imaging suggests that traumatic brain injury (TBI) may be associated with disruption of neuronal networks, including the nigrostriatal dopaminergic pathway. However, to date deficits in pre- and/or postsynaptic dopaminergic neurotransmission have not been demonstrated in TBI using functional imaging. We therefore assessed dopaminergic function in ten TBI patients using [123I]2-β-carbomethoxy-3-β-(4-iodophenyl)tropane (β-CIT) and [123I]iodobenzamide (IBZM) single-photon emission tomography (SPET). Average Glasgow Coma Scale score (±SD) at the time of head trauma was 5.8±4.2. SPET was performed on average 141 days (SD ±92) after TBI. The SPET images were compared with structural images using cranial computerised tomography (CCT) and magnetic resonance imaging (MRI). SPET was performed with an ADAC Vertex dual-head camera. The activity ratios of striatal to cerebellar uptake were used as a semiquantitative parameter of striatal dopamine transporter (DAT) and D2 receptor (D2R) binding. Compared with age-matched controls, patients with TBI had significantly lower striatal/cerebellar β-CIT and IBZM binding ratios (P≤0.01). Overall, the DAT deficit was more marked than the D2R loss. CCT and MRI studies revealed varying cortical and subcortical lesions, with the frontal lobe being most frequently affected whereas the striatum appeared structurally normal in all but one patient. Our findings suggest that nigrostriatal dysfunction may be detected using SPET following TBI despite relative structural preservation of the striatum. Further investigations of possible clinical correlates and efficacy of dopaminergic therapy in patients with TBI seem justified.
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  • 2
    ISSN: 1619-7089
    Keywords: Dementia of the Alzheimer type ; Diffuse Lewy body disease ; Single-photon emission tomography ; Brain perfusion patterns ; Dopamine transporter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Dementia of the Alzheimer-type (DAT) is characterized by progressive cognitive decline, variably combined with frontal lobe release signs, parkinsonian symptoms and myoclonus. The features of diffuse Lewy body disease (DLBD), the second most common cause of degenerative dementia, include progressive cognitive deterioration, often associated with levodopa-responsive parkinsonism, fluctuations of cognitive and motor functions, psychotic symptoms (visual and auditory hallucinations, depression), hypersensitivity to neuroleptics and orthostatic hypotension. A recent report suggests that positron emission tomography studies in patients with degenerative dementia may be useful in the differential diagnosis of DAT and DLBD. However, the diagnostic role of single-photon emission tomography (SPET) studies remains to be established. The aim of this study was therefore to evaluate regional cerebral perfusion [with either technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) or99mTc-ethyl cysteinate dimer (99mTc-ECD) SPET] and striatal dopamine transporter density [using iodine-123 2β-carboxymethoxy-3β-[4-iodophenyl]tropane (123I-β-CIT) SPET] in patients with DAT and DLBD. Six patients with probable DAT and seven patients with probable DLBD were studied. Blinded qualitative assessment by four independent raters of99mTc-HMPAO or99mTc-ECD SPET studies revealed bilateral temporal and/or parietal hypoperfusion in all DAT patients. There was additional frontal hypoperfusion in two patients and occipital hypoperfusion in one patient. In the DLBD group, regional cerebral perfusion had a different pattern. In addition to temporoparietal hypoperfusion there was occipital hypoperfusion resembling a horseshoe defect in six of seven patients. In the DAT group, the mean 3-h striatal/cerebellar ratio of123I-β-CIT binding was 2.5±0.4, with an increase to 5.5±1.1 18 h after tracer injection. In comparison, in the DLBD patients the mean 3-h striatal/cerebellar ratio of123I-β-CIT binding was significantly reduced to 1.7±0.3, with a modest increase to 2.1±0.4 18 h after tracer injection (P〈0.05, Scheffe test, ANOVA). These results suggest that99mTc-HMPAO or99mTc-ECD and123I-β-CIT SPET may contribute to the differential diagnosis between DAT and DLBD, showing different perfusion patterns and more severe impairment of dopamine transporter function in DLBD than in DAT.
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  • 3
    ISSN: 1619-7089
    Keywords: Key words: Dementia of the Alzheimer type ; Diffuse Lewy body disease ; Single-photon emission tomography ; Brain perfusion patterns ; Dopamine transporter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Dementia of the Alzheimer-type (DAT) is characterized by progressive cognitive decline, variably combined with frontal lobe release signs, parkinsonian symptoms and myoclonus. The features of diffuse Lewy body disease (DLBD), the second most common cause of degenerative dementia, include progressive cognitive deterioration, often associated with levodopa-responsive parkinsonism, fluctuations of cognitive and motor functions, psychotic symptoms (visual and auditory hallucinations, depression), hypersensitivity to neuroleptics and orthostatic hypotension. A recent report suggests that positron emission tomography studies in patients with degenerative dementia may be useful in the differential diagnosis of DAT and DLBD. However, the diagnostic role of single-photon emission tomography (SPET) studies remains to be established. The aim of this study was therefore to evaluate regional cerebral perfusion [with either technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) or 99mTc-ethyl cysteinate dimer (99mTc-ECD) SPET] and striatal dopamine transporter density [using iodine-123 2β-carboxymethoxy-3β-[4-iodophenyl]tropane (123I-β-CIT) SPET] in patients with DAT and DLBD. Six patients with probable DAT and seven patients with probable DLBD were studied. Blinded qualitative assessment by four independent raters of 99mTc-HMPAO or 99mTc-ECD SPET studies revealed bilateral temporal and/or parietal hypoperfusion in all DAT patients. There was additional frontal hypoperfusion in two patients and occipital hypoperfusion in one patient. In the DLBD group, regional cerebral perfusion had a different pattern. In addition to temporoparietal hypoperfusion there was occipital hypoperfusion resembling a horseshoe defect in six of seven patients. In the DAT group, the mean 3-h striatal/cerebellar ratio of 123I-β-CIT binding was 2.5±0.4, with an increase to 5.5±1.1 18 h after tracer injection. In comparison, in the DLBD patients the mean 3-h striatal/cerebellar ratio of 123I-β-CIT binding was significantly reduced to 1.7±0.3, with a modest increase to 2.1±0.4 18 h after tracer injection (P〈0.05, Scheffe test, ANOVA). These results suggest that 99mTc-HMPAO or 99mTc-ECD and 123I-β-CIT SPET may contribute to the differential diagnosis between DAT and DLBD, showing different perfusion patterns and more severe impairment of dopamine transporter function in DLBD than in DAT.
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  • 4
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Behavioural studies indicate that a newly acquired motor skill is rapidly consolidated from an initially unstable state to a more stable state, whereas neuroimaging studies demonstrate that the brain engages new regions for performance of the task as a result of this consolidation. However, it ...
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  • 5
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Recent studies have demonstrated that the downstream caspases, such as caspase 3, act as executors of the apoptotic cascade after traumatic brain injury (TBI) in vivo. However, little is known about the involvement of caspases in the initiation phase of apoptosis, and the interaction between these initiator caspases (e.g. caspase 8) and executor caspases after experimental brain injuries in vitro and in vivo. This study investigated the temporal expression and cell subtype distribution of procaspase 8 and cleaved caspase 8 p20 from 1 h to 14 days after cortical impact-induced TBI in rats. Caspase 8 messenger RNA levels, estimated by semiquantitaive RT-PCR, were elevated from 1 h to 72 h in the traumatized cortex. Western blotting revealed increased immunoreactivity for procaspase 8 and the proteolytically active subunit of caspase 8, p20, in the ipsilateral cortex from 6 to 72 h after injury, with a peak at 24 h after TBI. Similar to our previous studies, immunoreactivity for the p18 fragment of activated caspase 3 also increased in the current study from 6 to 72 h after TBI, but peaked at a later timepoint (48 h) as compared with proteolyzed caspase 8 p20. Immunohistologic examinations revealed increased expression of caspase 8 in neurons, astrocytes and oligodendrocytes. Assessment of DNA damage using TUNEL identified caspase 8- and caspase 3-immunopositive cells with apoptotic-like morphology in the cortex ipsilateral to the injury site, and immunohistochemical investigations of caspase 8 and activated caspase 3 revealed expression of both proteases in cortical layers 2–5 after TBI. Quantitative analysis revealed that the number of caspase 8 positive cells exceeds the number of caspase 3 expressing cells up to 24 h after impact injury. In contrast, no evidence of caspase 8 and caspase 3 activation was seen in the ipsilateral hippocampus, contralateral cortex and hippocampus up to 14 days after the impact. Our results provide the first evidence of caspase 8 activation after experimental TBI and suggest that this may occur in neurons, astrocytes and oligodendrocytes. Our findings also suggest a contributory role of caspase 8 activation to caspase 3 mediated apoptotic cell death after experimental TBI in vivo.
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  • 6
    ISSN: 1432-1459
    Keywords: Key words Parkinsonism ; Questionnaire ; Sensitivity ; Specificity ; Validity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract As part of a larger epidemiological study [Neuro-Epidemiology Project South-Tyrol (NEPT)], we investigated the accuracy of a mail questionnaire for parkinsonism in two languages (German and Italian). We administered the instrument to 40 randomly selected subjects with parkinsonism (Italian-speaking, n = 20; German-speaking, n = 20), attending our Parkinson’s disease clinic regularly. Each patient was matched by age, sex and language with a subject without parkinsonism residing in the same South-Tyrol Province in Northern Italy. Subjects free of parkinsonism were recruited randomly from two group practices collaborating in the NEPT study. A questionnaire containing nine symptom questions and two additional questions about the patient’s diagnosis of parkinsonism and/or treatment was mailed to each subject’s home. Forty subjects with parkinsonism and 36 without parkinsonism participated in the study. All nine symptom items showed significant differences between affected and unaffected individuals. A combination of any three questions yielded the best balance between sensitivity (95%) and specificity (89%). There were no differences between the German- and Italian-speaking groups. We demonstrated the usefulness of a simple questionnaire for validating the diagnosis of parkinsonism irrespective of the primary native language.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 243 (1996), S. 611-611 
    ISSN: 1432-1459
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 8
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] To the editor Zuscik and colleagues report transgenic mice with overexpression of the α1B-adrenergic receptor (α1BAR) leading to apoptotic neurodegeneration in α1B-expressing domains including cerebral cortex, hypothalamus, thalamus and cerebellum. Moreover, their model showed a ...
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