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PubMed1998

Accuracy of the clinical diagnosis of postencephalitic parkinsonism: a clinicopathologic study.

The accuracy of the clinical diagnosis of postencephalitic parkinsonism (PEP) is unknown. We determined the validity of the clinical diagnosis of PEP by presenting 105 records with neuropathologic diagnoses of PEP (n = 7), progressive supranuclear palsy (n = 24), Parkinson's disease (n = 15), dementia with Lewy bodies (n = 14), multiple system atrophy (n = 16), corticobasal degeneration (n = 10), Creutzfeldt-Jakob disease (n = 4), and other dementia disorders (n = 15), as clinical vignettes to six neurologists unaware of the autopsy findings. The neurologists' own clinical diagnoses were compared with neuropathologic diagnoses for measures of diagnostic accuracy, including reliability (kappa statistics), sensitivity and positive predictive values for the first and last visits. The group reliability for the diagnosis of PEP was almost perfect (kappa = 0.91, 0.9). The mean sensitivity at the first visit was 86% (range, 71-100%) with minimal change at the last visit (83%; range, 71-100%). Positive predictive values remained unchanged (100%). The high reliability, sensitivity and positive predictive values of the clinical diagnosis of PEP indicate that neurologists identify this disorder even when they report that they have never evaluated a case. In our data set, the best predictors for the diagnosis of PEP included onset below middle age; symptom duration lasting more than 10 years, and the presence of oculogyric crisis. History of encephalitis lethargica, present in most PEP cases, was an important individual diagnostic predictor. Copyright 1998 Lippincott Williams & Wilkins

Journal Article↗

PubMed1998

Artefacts in HPLC detection of 3-nitrotyrosine in human brain tissue.

An HPLC method was used for quantification of 3-nitrotyrosine (3-NT) in human postmortem brain tissue. A peak with similar retention time to 3-NT was detected in brain tissue from patients with Parkinson's disease, Huntington's chorea, multiple system atrophy, and Alzheimer's disease but not in control tissue. The peak was lost on reduction with dithionite, a criterion often used to identify 3-NT. Tissue from the same neurodegenerative diseases was analysed by HPLC using a photodiode array detector in series with an amperometric electrochemical detector, but the peak was found not to be 3-NT. The absorbance spectrum, fragmentation pattern on mass spectroscopy, and electrochemical profile of this peak do not match authentic 3-NT. A search of the mass spectroscopy databases failed to reveal its identity. The presence of this closely eluting, dithionite-reducible peak could confound analysis of human tissues for 3-NT. In vitro experiments showed that high concentrations of peroxynitrite were needed to achieve detectable levels of 3-NT in human brain tissue.

Artifacts↗

PubMed2002

Regulation of cerebral blood flow in patients with autonomic dysfunction and severe postural hypotension.

BACKGROUND: Whether cerebral blood flow (CBF) autoregulation is maintained in autonomic dysfunction has been debated for a long time, and the rather sparse data available are equivocal. The relationship between CBF and mean arterial blood pressure (MABP) was therefore tested in eight patients with symptoms and signs of severe cardiovascular autonomic dysfunction. PATIENTS AND METHODS: Eight patients were included, three of whom had Parkinson's disease, three diabetes, one pure autonomic failure and the last one had multiple system atrophy. By the use of two techniques, the arteriovenous oxygen [(a-v)O2] method and xenon-inhalation with single photon emission tomography, 15 measurements (range 10-20) and three to four CBF measurements, respectively, were obtained in each patient. Following CBF measurements during baseline, MABP was raised gradually using intravenous noradrenaline infusion, and then lowered by application of lower body negative pressure. From the (a-v)O2 samples the CBF response to changes in MABP was evaluated using a computer program fitting one or two regression lines through the plot. RESULTS AND CONCLUSION: Preserved autoregulation was observed in three patients, while the remaining five patients showed a linear relationship between CBF and MABP. Comparison of the results of the tomographic CBF measurements to the (a-v)O2 data demonstrated that it is not possible to assess whether CBF is autoregulated or not with only three to four pairs of data.

Administration, Inhalation↗

PubMed2002

[Dementia with Lewy bodies].

Dementia with Lewy bodies (DLB) is the second most frequent neuropathologically diagnosed degenerative dementing illness. The clinical characteristics are progressive dementia, Parkinson syndrome, fluctuations of cognitive functions, vigilance and attention, visual hallucinations (usually detailed and well described), depression, REM-sleep behavior disorder, adverse responses to standard doses of neuroleptics, falls, syncopes, systematized delusions, and non-visual hallucinations. Mean age at disease onset ranges between 60 and 68 years. Male persons are more frequently affected than female. Disease duration is six to seven years. The differential diagnoses of DLB are dementia of the Alzheimer-type, Parkinson's disease, subcortical arteriosclerotic encephalopathy, progressive supranuclear palsy, multiple system atrophy, and, in rare cases, Creutzfeldt-Jakob disease. The genetic background of the disease is unclear. Magnetic resonance imaging and single photon emission tomography can contribute to the diagnosis. The disease is treated with L-dopa, atypical neuroleptics, acetylcholine esterase inhibitors, antihypotensive agents, and peripheral anticholinergic and alpha-receptor-blocking medicaments to improve neurogenic bladder dysfunction.

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PubMed2003

Dementia with Lewy bodies.

The objective was to summarize recent findings about the clinical features, diagnosis and investigation of dementia with Lewy (DLB) bodies, together with its neuropathology, neurochemistry and genetics. Dementia with Lewy bodies (DLB) is a primary, neurodegenerative dementia sharing clinical and pathological characteristics with both Parkinson's disease (PD) and Alzheimer's disease (AD). Antiubiquitin immunocytochemical staining, developed in the early 1990s, allowed the frequency and distribution of cortical LBs to be defined. More recently, alpha-synuclein antibodies have revealed extensive neuritic pathology in DLB demonstrating a neurobiological link with other "synucleinopathies" including PD and multiple system atrophy (MSA). The most significant correlates of cognitive failure in DLB appear to be with cortical LB and Lewy neurites (LNs) rather than Alzheimer type pathology. Clinical diagnostic criteria for DLB, published in 1996, have been subjected to several validation studies against autopsy findings. These conclude that although diagnostic specificity is high (range 79- 100%, mean 92%), sensitivity is lower (range 0- 83 %, mean, 49%). Improved methods of case detection are therefore required. Fluctuating impairments in attention, visual recognition and construction are more indicative of DLB than AD. Relative preservation of medial temporal lobe volume on structural MRI and the use of SPECT tracers for regional blood flow and the dopamine transporter are the most reliable current biomarkers for DLB. There are no genetic or CSF tests recommended for the diagnosis of DLB at present. Between 15 and 20% of all elderly demented cases reaching autopsy have DLB, making it the most common cause of degenerative dementia after AD. Exquisite, not infrequently fatal, sensitivity to neuroleptic drugs and encouraging reports of the effects of cholinesterase inhibitors on cognitive, psychiatric and neurological features, mean that an accurate diagnosis of DLB is more than merely of academic interest. Dementia developing late in the course of PD shares many of the same clinical and pathological characteristics.

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PubMed2003

Other autonomic neuropathies.

Acquired forms of autonomic neuropathy may be isolated or may coexist with somatic neuropathy. Clinical identification of symptoms and signs in the patient with autonomic dysfunction is crucial in the diagnosis of autonomic neuropathy and its separation from pure autonomic failure or multiple system atrophy. Once an autonomic neuropathy has been identified, several clinical features can be useful in the diagnosis of a specific form of autonomic neuropathy. Other factors, such as the presence of somatic neuropathy and systemic disease, are critical for diagnosis. This article reviews the clinical presentation, diagnosis, pathogenesis, and management of the acquired forms of autonomic neuropathy.

Animals↗

PubMed2003

Imaging of the autonomic nervous system: focus on cardiac sympathetic innervation.

Symptoms or signs of abnormal autonomic nervous system function occur commonly in several neurological disorders. Clinical evaluations have depended on physiological, pharmacological, and neurochemical approaches. Recently, imaging of sympathetic noradrenergic innervation has been introduced and applied especially in the heart. Most studies have used the radiolabeled sympathomimetic amine, (123)I-metaiodobenzylguanidine. Decreased uptake or increased "washout" of (123)I-metaiodobenzylguanidine-derived radioactivity is associated with worse prognosis or more severe disease in hypertension, congestive heart failure, arrhythmias, and diabetes mellitus. This pattern may reflect a high rate of postganglionic sympathetic nerve traffic to the heart. Many recent studies have agreed on the remarkable finding that all patients with Parkinson's disease and orthostatic hypotension have a loss of cardiac sympathetic innervation, whereas all patients with multiple system atrophy, often difficult to distinguish clinically from Parkinson's disease, have intact cardiac sympathetic innervation. Because Parkinson's disease entails a postganglionic sympathetic noradrenergic lesion, the disease appears to be not only a movement disorder, with dopamine loss in the nigrostriatal system of the brain, but also a dysautonomia, with noradrenaline loss in the sympathetic nervous system of the heart. As new ligands are developed, one may predict further discoveries of involvement of components of the autonomic nervous system in neurological diseases.

Adrenergic Fibers↗

PubMed2003

Treatment of orthostatic hypotension.

Orthostatic hypotension is the most incapacitating symptom of autonomic failure. This disorder occurs with both central autonomic neurodegenerative disorders, such as multiple system atrophy and Parkinson's disease, and peripheral autonomic disorders, such as the autonomic peripheral neuropathies and pure autonomic failure. The hallmark of both central and peripheral causes of neurogenic orthostatic hypotension is the failure to release norepinephrine appropriately upon standing. Patient education is the cornerstone of management. There are several measures that can be implemented to improve orthostatic tolerance prior to pharmacological intervention. Plasma volume expansion is essential to improve orthostatic tolerance, and fluid and sodium chloride intake should be increased. Most patients can be treated successfully with volume expansion or fludrocortisone or both in combination with a sympathomimetic agent. Desmopressin acetate and erythropoietin are useful supplementary agents in patients with more refractory symptoms. There are rare patients who will require additional agents to treat their symptoms. A small group of patients remain refractory to all therapeutic modalities.

Animals↗

PubMed2003

Evaluation and treatment of autonomic disorders of the urogenital system.

Autonomic pathways are important in the regulation of both lower urinary tract and sexual function, and their interruption in neurological pathologies predictably results in variable urogenital dysfunction, depending mainly on the level of the lesion. A normal neurological examination of a patient with urogenital complaints should exclude an underlying neurological pathology, and the neurologist should become involved in the management of symptoms. Electromyography can be of value in the diagnosis and management of cauda equina lesions and multiple system atrophy, but neurophysiological investigations are of no importance in the diagnosis of neurogenic sexual dysfunction. Urodynamic studies have proven helpful in determining the type and management of lower urinary tract dysfunction. Oral anticholinergics usually combined with clean intermittent catheterizations are the first-line treatment options for neurogenic lower urinary tract dysfunction, with intravesical treatments emerging as the main alternative in intractable incontinence. The availability of effective oral phosphodiesterase inhibitors has revolutionized the management of erectile dysfunction, but treatment of ejaculatory and orgasmic disorders as well as of female sexual dysfunction still remains problematic.

Animals↗

PubMed2003

Evaluation and treatment of autonomic disorders of the gastrointestinal tract.

Despite the extensive impact of autonomic function on the gastrointestinal system, there is little understanding of the mechanisms by which specific autonomic abnormalities translate into particular gastrointestinal complaints. Three logical alternatives include: (1) the underlying disorder affects the autonomic and gastrointestinal systems independently; (2) autonomic dysfunction alters gastrointestinal processing directly; (3) gastrointestinal manifestations arise as a delayed, indirect consequence of autonomic dysfunction. The major gastrointestinal manifestations of dysautonomia include esophageal dysmotility such as achalasia, gastroparesis, and small bowel bacterial overgrowth in the upper tract. Lower tract disorders include diarrhea, fecal incontinence, and constipation. Sorting through the varied causes of these disorders requires a careful history and examination in each patient. Supportive diagnostic studies may include radionuclide imaging, motility examination, and electrogastrography. Autonomic studies can (1) distinguish a purely enteric from a more generalized dysautonomia; (2) provide surrogate information about motility; (3) differentiate primary (e.g., multiple system atrophy) from secondary (e.g., irritable bowel syndrome) dysautonomias as the etiology of gastrointestinal symptoms. Several new strategies are available for the treatment of gastroparesis, constipation, irritable bowel, and sphincteric incontinence.

Animals↗

PubMed2007

Dementia with Lewy bodies.

Synucleinopathies, with and without dementia, encompass a wide range of diseases including Parkinson's disease, multiple system atrophy, rapid eye movement (REM) sleep behavior disorder, and dementia with Lewy bodies (DLB). DLB is a neurodegenerative disorder resulting in slowly progressive and unrelenting dementia until death. Prevalence studies suggest that it is the second most common dementing illness in the elderly. The neuropathologic findings of DLB show a wide anatomic range. Lewy bodies and Lewy-related pathology are found from the brain stem to the cortex and, in many cases, associated with concurrent Alzheimer's disease pathology. A recent international consortium on DLB has resulted in revised criteria for the clinical and pathological diagnosis of DLB incorporating new information about the core clinical features and improved methods for their assessment. The presentation of DLB is typically one of cortical and subcortical cognitive impairments, with worse visuospatial and executive dysfunction than Alzheimer's disease. There may be relative sparing of memory especially in the early stages. Core clinical features of DLB include fluctuating attention, recurrent visual hallucinations, and parkinsonism. Suggestive features include REM sleep behavior disorder, severe neuroleptic sensitivity, and low dopamine transporter uptake in the basal ganglia on functional neuroimaging. Additional supportive features that commonly occur in DLB, but with lower specificity, include repeated falls and syncope, transient, unexplained loss of consciousness, severe autonomic dysfunction, hallucinations in other modalities, systematized delusions, depression, relative preservation of medial temporal lobe structures on structural neuroimaging, reduced occipital activity on functional neuroimaging, prominent slow wave activity on electroencephalogram, and low uptake myocardial scintigraphy. Management of DLB includes pharmacological and nonpharmacological interventions for its cognitive, neuropsychiatric, motor, and sleep disturbances.

Brain↗

PubMed2003

Tissue transglutaminase-induced aggregation of alpha-synuclein: Implications for Lewy body formation in Parkinson's disease and dementia with Lewy bodies.

Proteinaceous aggregates containing alpha-synuclein represent a feature of neurodegenerative disorders such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Despite extensive research, the mechanisms underlying alpha-synuclein aggregation remain elusive. Previously, tissue transglutaminase (tTGase) was found to contribute to the generation of aggregates by cross-linking pathogenic substrate proteins in Huntington's and Alzheimer's diseases. In this article, the role of tTGase in the formation of alpha-synuclein aggregates was investigated. Purified tTGase catalyzed alpha-synuclein cross-linking, leading to the formation of high molecular weight aggregates in vitro, and overexpression of tTGase resulted in the formation of detergent-insoluble alpha-synuclein aggregates in cellular models. Immunocytochemical studies demonstrated the presence of alpha-synuclein-positive cytoplasmic inclusions in 8% of tTGase-expressing cells. The formation of these aggregates was significantly augmented by the calcium ionophore and prevented by the inhibitor cystamine. Immunohistochemical studies on postmortem brain tissue confirmed the presence of transglutaminase-catalyzed epsilon (gamma-glutamyl)lysine cross-links in the halo of Lewy bodies in Parkinson's disease and dementia with Lewy bodies, colocalizing with alpha-synuclein. These findings, taken together, suggest that tTGase activity leads to alpha-synuclein aggregation to form Lewy bodies and perhaps contributes to neurodegeneration.

Animals↗

PubMed2001

Stabilization of partially folded conformation during alpha-synuclein oligomerization in both purified and cytosolic preparations.

Aggregation of alpha-synuclein is tightly associated with many neurodegenerative diseases, such as Parkinson's disease, dementia with Lewy body, Lewy body variant of Alzheimer's disease, multiple system atrophy, and Hallervorden-Spatz disease, implicating a crucial role of aggregated forms of alpha-synuclein in the pathogenesis. Here, we examined the effect of elevated temperature on the oligomerization and structural changes of alpha-synuclein in the early stage of aggregation and show that self-assembly is crucial for the stabilization of a partially folded conformation. The efficiency of alpha-synuclein oligomerization increased proportional to the temperature increase, both in purified form and in crude cytosolic preparation. This oligomerization coincided with a small but reproducible change in the circular dichroism spectrum and an increase in the 1-anilinonaphthalene-8-sulfonic acid binding. The hydrodynamic dimensions of the dimer measured by size exclusion chromatography suggest a pre-molten globule-like structure. These data suggest that partially folded alpha-synuclein, which is unstable in the monomeric form, is stabilized by self-assembly and that these oligomers may evolve into the fibril nucleus.

Animals↗

PubMed2000

alpha-Synuclein membrane interactions and lipid specificity.

With the discovery of missense mutations (A53T and A30P) in alpha-synuclein (alpha-Syn) in several families with early onset familial Parkinson's disease, alpha-Syn aggregation and fibril formation have been thought to play a role in the pathogenesis of alpha-synucleinopathies, such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. As previous reports have suggested that alpha-Syn plays a role in lipid transport and synaptic membrane biogenesis, we investigated whether alpha-Syn binds to a specific lipid ligand using thin layer chromatography overlay and examined the changes in its secondary structure using circular dichroism spectroscopy. alpha-Syn was found to bind to acidic phospholipid vesicles and this binding was significantly augmented by the presence of phosphatidylethanolamine, a neutral phospholipid. We further examined the interaction of alpha-Syn with lipids by in situ atomic force microscopy. The association of soluble wild-type alpha-Syn with planar lipid bilayers resulted in extensive bilayer disruption and the formation of amorphous aggregates and small fibrils. The A53T mutant alpha-Syn disrupted the lipid bilayers in a similar fashion but at a slower rate. These results suggest that alpha-Syn membrane interactions are physiologically important and the lipid composition of the cellular membranes may affect these interactions in vivo.

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PubMed2001

Evidence for a partially folded intermediate in alpha-synuclein fibril formation.

Intracellular proteinaceous aggregates (Lewy bodies and Lewy neurites) of alpha-synuclein are hallmarks of neurodegenerative diseases such as Parkinson's disease, dementia with Lewy bodies, and multiple systemic atrophy. However, the molecular mechanisms underlying alpha-synuclein aggregation into such filamentous inclusions remain unknown. An intriguing aspect of this problem is that alpha-synuclein is a natively unfolded protein, with little or no ordered structure under physiological conditions. This raises the question of how an essentially disordered protein is transformed into highly organized fibrils. In the search for an answer to this question, we have investigated the effects of pH and temperature on the structural properties and fibrillation kinetics of human recombinant alpha-synuclein. Either a decrease in pH or an increase in temperature transformed alpha-synuclein into a partially folded conformation. The presence of this intermediate is strongly correlated with the enhanced formation of alpha-synuclein fibrils. We propose a model for the fibrillation of alpha-synuclein in which the first step is the conformational transformation of the natively unfolded protein into the aggregation-competent partially folded intermediate.

Humans↗

PubMed2001

alpha-Synuclein affects the MAPK pathway and accelerates cell death.

Insoluble alpha-synuclein accumulates in Parkinson's disease, diffuse Lewy body disease, and multiple system atrophy. However, the relationship between its accumulation and pathogenesis is still unclear. Recently, we reported that overexpression of alpha-synuclein affects Elk-1 phosphorylation in cultured cells, which is mainly performed by mitogen-activated protein kinases (MAPKs). We further examined the relationship between MAPK signaling and the effects of alpha-synuclein expression on ecdysone-inducible neuro2a cell lines and found that cells expressing alpha-synuclein had less phosphorylated MAPKs. Moreover, they showed significant cell death when the concentration of serum in the culture medium was reduced. Under normal serum conditions, the addition of the MAPK inhibitor U0126 also caused cell death in alpha-synuclein-expressing cells. Transfection of constitutively active MEK-1 resulted in MAPK phosphorylation in alpha-synuclein-expressing cells and improved cell viability even under reduced serum conditions. Thus, we conclude that alpha-synuclein regulates the MAPK pathway by reducing the amount of available active MAPK. Our findings suggest a mechanism for pathogenesis and thus offer therapeutic insight into synucleinopathies.

14-3-3 Proteins↗

PubMed2002

Phosphorylated alpha-synuclein is ubiquitinated in alpha-synucleinopathy lesions.

alpha-Synuclein is one of the major components of intracellular fibrillary aggregates in the brains of a subset of neurodegenerative disorders, including Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, and Hallervorden-Spatz disease, which are referred to as alpha-synucleinopathies. We have shown previously (Fujiwara, H., Hasegawa, M., Dohmae, N., Kawashima, A., Masliah, E., Goldberg, M. S., Shen, J., Takio, K., and Iwatsubo, T. (2002) Nat. Cell Biol. 4, 160-164) that alpha-synuclein deposited in synucleinopathy brains is extensively phosphorylated at Ser-129 and migrates at 15 kDa. Here we examined the biochemical characteristics of the additional, higher molecular mass species of phosphorylated alpha-synuclein-positive polypeptides that also are recovered in the Sarkosyl-insoluble fraction of synucleinopathy and migrate at about 22 and 29 kDa. These 22 and 29 kDa bands were positive for three different anti-ubiquitin antibodies and comigrated perfectly with in vitro ubiquitinated alpha-synuclein that may correspond to mono- and diubiquitinated alpha-synuclein, respectively. Furthermore, cyanogen bromide cleavage of the 22 and 29 kDa polypeptides shifted the mobility to 19 and 26 kDa, respectively, and they retained immunoreactivity for both ubiquitin and alpha-synuclein. Finally, protein sequence analysis showed that the 19 kDa band contained two amino-terminal sequences of alpha-synuclein and ubiquitin. These results strongly suggest that phosphorylated alpha-synuclein is targeted to mono- and diubiquitination in synucleinopathy brains, which may have implications for mechanisms of these diseases.

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PubMed2003

Association of the cytoskeletal GTP-binding protein Sept4/H5 with cytoplasmic inclusions found in Parkinson's disease and other synucleinopathies.

alpha-Synuclein-positive cytoplasmic inclusions are a pathological hallmark of several neurodegenerative disorders including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Here we report that Sept4, a member of the septin protein family, is consistently found in these inclusions, whereas five other septins (Sept2, Sept5, Sept6, Sept7, and Sept8) are not found in these inclusions. Sept4 and alpha-synuclein can also be co-immunoprecipitated from normal human brain lysates. When co-expressed in cultured cells, FLAG-tagged Sept4 and Myc-tagged alpha-synuclein formed detergent-insoluble complex, and upon treatment with a proteasome inhibitor, they formed Lewy body-like cytoplasmic inclusions. The tagged Sept4 and alpha-synuclein synergistically accelerated cell death induced by the proteasome inhibitor, and this effect was further enhanced by expression of another Lewy body-associated protein, synphilin-1, tagged with the V5 epitope. Moreover, co-expression of the three proteins (tagged Sept4, alpha-synuclein, and synphilin-1) was sufficient to induce cell death. These data raise the possibility that Sept4 is involved in the formation of cytoplasmic inclusions as well as induction of cell death in alpha-synuclein-associated neurodegenerative disorders.

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