Glial fibrillary tangles with straight tubules in the brains of patients with progressive supranuclear palsy

Transgenic expression of the shortest human tau affects its compartmentalization and its phosphorylation as in the pretangle stage of Alzheimer's disease

We have generated transgenic mice expressing the shortest human tau protein, the microtubule-associated protein that composes paired helical filaments in Alzheimer's disease. Transgenic tau transcripts and proteins were strongly expressed in neurons in the developing and adult brain. In contrast to the endogenous tau that progressively disappeared from neuronal cell bodies during development, the human transgenic tau remained abundant in cell bodies and dendrites of a subset of neurons in the adult. This somatodendritic transgenic tau was immunoreactive with antibodies to tau phosphorylated on Thr181 and Thr231 and with the conformation-dependent Alz50 antibody. A few astrocytes expressing the transgenic tau were strongly immunoreactive with antibodies to additional tau phosphorylation sites, ie, at Ser262/ 356 and Ser396/404. All of these phosphorylation sites have been identified in paired helical filaments-tau proteins. In electron microscopy, the transgenic tau was detected into microtubules in axons and in dendrites but not in cell bodies. Neurofibrillary tangles were not detected in transgenic animals examined up to the age of 19 months. These results indicate that transgenic manipulation of tau expression and intracellular targeting is sufficient per se to affect tau compartmentalization, phosphorylation, and conformation partly as it is observed at the pretangle stage in Alzheimer's disease.

Slowly progressive L-DOPA nonresponsive pure akinesia due to nigropallidal degeneration: a clinicopathological case study

We report an autopsy case of a 51-year old man who showed slowly progressive pure akinesia: freezing phenomenon and festination during 21 years of illness without tremor, rigidity, upward gaze palsy, bradykinesia and dementia, which were not responded to L-DOPA clinically. Neuropathological findings revealed the circumscribed regions in the substantia nigra and middle portion of the internal globus pallidus (GPi), without neurofibrillary tangles, neuropil threads, and glial fibrillary tangles. So this case was clearly distinguished with progressive nuclear palsy and pallidonigroluisian atrophy. It was first reported to describe that L-DOPA nonresponsive pure akinesia can arise from nigopallidal atrophy.

Recent advances in dementia research in Japan: non-Alzheimer-type degenerative dementias

In this article, we review recent reports by Japanese researchers on non-Alzheimer-type degenerative dementias. These dementias can be classified into the following subtypes: dementias with Lewy bodies, including diffuse Lewy body disease, dementias with neurofibrillary tangles, dementias with glial tangles, including progressive supranuclear palsy and corticobasal degeneration, argyrophilic grain dementia, frontotemporal dementias including Pick's disease; dementias with degeneration of subcortical nuclei, including Huntington's disease and, last, unclassified dementias. Recently, these various forms of dementia have received much attention in Japan, as elsewhere.

Regional quantitative analysis of tau-positive neurons in progressive supranuclear palsy: comparison with Alzheimer's disease

In patients with progressive supranuclear palsy (PSP), various tau-positive abnormal structures are found in the cerebral cortex as well as in the subcortical nuclei. Similar tau-positive abnormalities are also identified in cortico-basal degeneration (CBD). It is therefore questionable as to whether PSP can be neuropathologically differentiated from CBD. It also remains nuclear whether neurofibrillary tangles (NFT) in the cerebral cortex of PSP patients consist of PSP-NFT or concomitant Alzheimer's disease (AD)-NFT, although there have been some reports suggesting that PSP- and AD-NFT are different with respect to distribution pattern and biochemical character. In this study, a regional quantitative analysis of the distribution and antigenicity of tau-positive neurons (TPN) was performed in PSP cases and compared with that in AD cases. TPN consisted of NFT with tangle-formation and pretangle neurons (PN) without tangle-formation. In addition, NFT were subdivided into mature and immature NFT according to the difference of staining properties with anti-tau-related antibodies. The comparison of the TPN of the PSP cases with those of the AD cases revealed that the degree of tangle-formation in the TPN of AD was similar in all of the examined regions, while that in the TPN of PSP varied according to the region and case. Moreover, the NFT in the PSP and AD cases had different distributions according to the cortical layer and subnucleus, even in the common predilection sites of PSP and AD, suggesting that NFT in these regions of the PSP cases consist mainly of PSP-NFT. In addition, the PSP cases could be divided into two groups according to the difference of the tangle-formation of TPN; group I with typical PSP pathology and group II with atypical PSP pathology similar to CBD. This suggests that there is a continuity between PSP and CBD with respect to the distribution and antigenicity of TPN.

Relationship between brainstem MRI and pathological findings in progressive supranuclear palsy--study in autopsy cases

The relationship between the features of MRI in brainstem and pathological findings was investigated in eight autopsy cases with progressive supranuclear palsy (PSP). Features of T1-weighted images at midbrain level were atrophy of tegmentum and tectum, and dilatation of aqueduct. Histologically, these findings were consistent with atrophy of periaqueductal gray matter, quadrigeminal plate, and tegmentum. In these lesions, we detected neuronal loss, decrease in density of myelinated fibers, gliosis, rarefaction of tissues, and tau-positive structures such as neurofibrillary tangles (NFTs), glial fibrillary tangles (GFTs) and neuropil threads. At pons level, atrophy of tegmentum, atrophy of pontine base, and dilatation of prepontine cistern were found. Tau-positive structures were observed not only in tegmentum but also in pontine base. The density of the tau-positive structure was closely related to the severity of atrophy. Features of T2-weighted images were high intensity in the periaqueductal lesion and tegmentum in pons. In these lesions, severe histological findings were detected. The MRI features in brainstem were closely related to the histological findings as PSP.

Rapid alteration of tau in oligodendrocytes after focal ischemic injury in the rat: involvement of free radicals

Glial inclusions containing the microtubule-associated protein tau are present in a variety of chronic neurodegenerative conditions. We now report a rapid and time-dependent increase of tau immunoreactivity within oligodendrocytes after focal cerebral ischemia in the rat. The number of tau positive oligodendrocytes in the ipsilateral subcortical white matter increased six- to eightfold by 40 minutes after permanent middle cerebral artery occlusion (MCAO). Tau was detected using antibodies that label both the N- and C-terminal of the protein, suggesting accumulation of full-length protein within these cells. Pretreatment with the spin trap agent alpha-phenyl-tert-butyl-nitrone (PBN)(100mg/kg) reduced the number of tau-positive oligodendrocytes by 55% in the subcortical white matter of the ischemic hemisphere compared with untreated animals at 40 minutes after MCAO. In contrast, pretreatment with glutamate receptor antagonists MK-801 (0.5 mg/kg) or 2,3-dihydroxy-6-nitro-7-sulpfamoyl-benzo(f)quinoxaline (NBQX) (2 x 30 mg/kg), failed to reduce the number of tau-positive oligodendrocytes after 40 minutes of ischemia. The results indicate that oligodendrocytes respond rapidly to an ischemic challenge and that free radical-mediated mechanisms are involved in the cascade leading to increased tau immunoreactivity.

The effect of postmortem delay on the distribution of microtubule-associated proteins tau, MAP2, and MAP5 in the rat

Breakdown or disruption of the cytoskeleton has been implicated in the neurodegenerative processes of a variety of diseases, including Alzheimer disease (AD) and stroke. Studies of such diseases in the human involve the use of postmortem brain tissue. Postmortem delay may vary considerably from a few hours to a few days, and within this period, a degree of cytoskeletal breakdown may occur. It is therefore crucial to examine alterations occurring in the cytoskeleton as a result of postmortem delay and subtract these from those caused by the disease. In this study, the distribution of tau, MAP2, and MAP5 immunohistochemistry was examined following postmortem intervals of 0-72 h in the rat cerebral cortex, corpus callosum, caudate nucleus, and hippocampus. Each microtubule-associated protein (MAP) underwent unique changes that were dependent both on postmortem interval and the brain region examined. Following long postmortem delays, some of the changes in these proteins were similar to those seen in rodent models of cerebral ischemia. These results demonstrate that MAPs are not stable during postmortem delay in the rat. Therefore, caution must be exercised when interpreting changes in MAPs in human postmortem tissue, especially in cases where ischemic injury may be involved. Examination of control tissue carefully matched for postmortem delay is therefore essential to allow meaningful interpretation of cytoskeletal abnormalities in human neurodegenerative disease.

Increased tau immunoreactivity in oligodendrocytes following human stroke and head injury

Tau immunohistochemistry was performed on post-mortem brain tissue from patients who died following head injury or stroke and from neurologically normal controls. Tau-positive oligodendrocytes were detected with three different tau antibodies in head injured or stroke patients, but not in control cases. Tau-positive oligodendrocytes were detected 2 h following head injury indicating that accumulation of tau may be an acute response of these cells to brain injury. The mechanisms underlying accumulation of tau in oligodendrocytes after acute brain injury may be similar to those which occur in chronic neurodegenerative conditions such as progressive supranuclear palsy (PSP) and multi-system atrophy (MSA).

Neurodegenerative disorders with extensive tau pathology: a comparative study and review

Many neurodegenerative disorders with onset in mid to late adult life present diagnostic challenges to clinicians and pathologists alike. A distinguishing neuropathological feature has traditionally been the presence or absence of neurofibrillary tangles. Recent biochemical and molecular biological studies have identified the microtubule-binding protein tau as the predominant component of these and related inclusions, and have provided powerful new reagents for the study of neurodegenerative diseases. Several diseases previously considered distinct pathophysiological entities contain similar tau-immunoreactive lesions, but qualitative and regional anatomical differences in vulnerability can differentiate the disorders. Comparison of tau-immunoreactive lesions in three relatively uncommon neurodegenerative diseases-progressive supranuclear palsy, Pick's disease, and corticobasal degeneration-illustrates the types of analyses that demonstrate unexpected pathological similarities, but also fundamental differences between these disorders. These results have important implications for the differential diagnosis of disorders containing tau-immunoreactive lesions, including Alzheimer's disease.

Corticobasal degeneration: widespread argentophilic threads and glia in addition to neurofibrillary tangles. Similarities of cytoskeletal abnormalities in corticobasal degeneration and progressive supranuclear palsy

A 57-year-old man had exhibited cortical sensory disturbance, rigidity, spasticity, dementia, alien hand, grasp reflex, supranuclear ophthalmoplegia, pseudobulbar palsy, and neck dystonia for 4 years. Histological examination of autopsied specimens revealed neuronal loss in the cerebral cortex, with ballooned neurons, subthalamic nucleus, substantia nigra, basal ganglia, midbrain tegmentum, and the thalamus. There were neurofibrillary tangles in the subthalamic nucleus and the substantia nigra. Gallyas-Braak silver impregnation demonstrated numerous argentophilic tangles, threads, and a few argentophilic glia in the cerebral cortex, subcortical white matter, particularly in the precentral gyrus, subcortical nuclei, and the brainstem. These argentophilic structures were largely positive for tau, and negative for ubiquitin, paired helical filaments, and phosphorylated neurofilament. Ultrastructurally, 15-nm-wide straight tubules were observed in the neurons of the substantia nigra, globus pallidus, and the precentral cortex, coexisting with a few twisted tubules periodically constricted at 160- to 230-nm intervals. It was conclusively shown that Gallyas- and tau-positive cytoskeletal abnormalities occurred widely in brain of corticobasal degeneration. Both distribution and morphology of abnormal phosphorylated tau protein in corticobasal degeneration appear to resemble these features in progressive supranuclear palsy. These findings suggest a common cytoskeletal etiopathological significance in corticobasal degeneration and progressive supranuclear palsy.

Cytoskeletal pathology in non-Alzheimer degenerative dementia: new lesions in diffuse Lewy body disease, Pick's disease, and corticobasal degeneration

Increasing use of immunocytochemistry for evaluation of dementia disorders has revealed histopathological alterations that were previously unknown, even with sensitive silver techniques. Disorders [Pick's disease (PD), diffuse Lewy body disease (DLBD) and corticobasal degeneration (CBD)] in which immunocytochemistry has revealed occult pathology are discussed. All three disorders have neurofilament (NF) immunoreactive neuronal alterations in the neocortex. In DLBD round, eosinophilic cytoplasmic inclusions referred to as cortical Lewy bodies are neurofilament-positive, while in both PD and CBD neurofilament epitopes are expressed in irregularly swollen neurons and their proximal cell processes, which are referred to as ballooned neurons. Interestingly, the cortical neuronal population that is vulnerable to Lewy bodies is similar to that which is vulnerable to ballooned neurons. Furthermore, Lewy bodies can occasionally be detected within the cytoplasm of ballooned neurons. Besides neurofilament-immunoreactivity, Lewy bodies are immunoreactive for ubiquitin, while ballooned neurons are inconsistently stained with antibodies to ubiquitin. Both Lewy bodies and ballooned neurons can be appreciated with routine histology, but they are much easier to detect with immunocytochemistry. In contrast, a new type of neuritic alteration in the hippocampal CA2/3 region has been recognized in DLBD. These dystrophic neurites cannot be appreciated with routine histology and are only optimally seen with immunocytochemistry for ubiquitin. Their presence is a certain indication of the presence of cortical Lewy bodies. The microtuble associated protein tau is the major constituent of neurofibrillary tangles in Alzheimer's disease (AD). Biochemical studies have shown that Pick bodies, argyrophilic neuronal inclusions that are highly characteristic of, if not pathognomonic for PD are also composed of abnormal tau protein. Along with Pick bodies, tau has recently been detected in glial cells in PD. Similar so-called "gliofibrillary tangles" are increasingly recognized in progressive supranuclear palsy. Previously, CBD was considered to be free of such lesions, but recent studies have revealed widespread tau-positive neuronal and glial cytoskeletal lesions in CBD. A distinctive type of tau-positive glial lesion in CBD is characterized by annular clusters of grain-like tau immunoreactivity reminiscent of a neuritic plaque in AD, except that the clusters are devoid of amyloid. The tau-positive profiles are consistently located around a central astrocyte cell body. Double labeling studies with glial fibrillary acidic protein, vimentin and CD44, which are markers for reactive astrocytes, demonstrates tau immunoreactivity within astrocytic processes; these "astrocytic plaques" appear to be specific for CBD. Although NF, ubiquitin and tau proteins are present in diverse neuronal and glial inclusions in these disorders, the morphology and distribution of these lesions differentiate non-AD dementias.

Immunohistochemical investigation of tau-positive structures in the cerebral cortex of patients with progressive supranuclear palsy

We have investigated tau-positive structures immunohistochemically in the cerebral cortex of patients with progressive supranuclear palsy (PSP). In addition to neurofibrillary tangles, a variety of tau-positive structures occur. They are particularly abundant in the precentral gyrus and other frontal cortices. Double immunostaining has demonstrated that coil-like structures (coiled bodies) are located in the oligodendroglial cell bodies. Three forms of tau-positive astrocytic inclusions are discerned: those with tuft-like profiles, thorn-like structures, and concentric clusters of short stubby fibers. The concentric clusters of tau-positive fibers are present in some, but not all, PSP brains. They appear to be identical to 'astrocytic plaques' previously reported in patients with corticobasal degeneration (CBD). PSP and CBD might share a common pathological background which causes abnormal accumulation of tau protein in neurons and glial cells of neuroectodermal origin.

Thorn-shaped astrocytes: possibly secondarily induced tau-positive glial fibrillary tangles

Argyrophilic and tau-positive abnormal structures occurring in glial cells are called glial fibrillary tangles. In the astrocyte, a conspicuous tau-positive structure is known to appear in progressive supranuclear palsy (PSP). In this report, another type of argyrophilic and tau-positive astrocytes is reported. The morphology of this new type is quite different from that of the previously reported tau-positive astrocyte in PSP and they are designated here as thorn-shaped astrocytes (TSA). TSA have an apparently argyrophilic cytoplasm with a few short processes and often have a small eccentric nucleus, whose appearance resembles that of a reactive astrocyte. Immunohistochemically, TSA are positive to anti-tau antibodies but are negative for ubiquitin. Simultaneous immunostaining revealed the coexistence of tau and glial fibrillary acidic protein epitopes in the same cytoplasm. Electron microscopically, bundles of 15-nm straight tubules were included in the cytoplasm together with abundant glial filaments. In the vicinity of a cluster of TSA, related structures of perivascular or subpial tau-positive linings, which correspond to astrocytic end-feet, are sometimes observed. In almost all cases, a few TSA are generally located in a confined area of subpial and subependymal regions. Although TSA appear to be intimately associated with some diseases, they are also found in a wide range of cytoskeletal disorders including the aged brain with neurofibrillary tangles. TSA are presumed to be a secondary induced product in relation to astrocytic reaction.

Achromatic neurons in the cortex of progressive supranuclear palsy

Achromatic neurons (AN) in the cerebral cortex are a characteristic feature of several neurodegenerative conditions including Pick's disease, corticobasal degeneration and some cases of primary progressive aphasia. Although AN are occasionally seen in some other diseases, their presence in progressive supranuclear palsy (PSP) has not been previously documented. We found significant numbers of AN in the cerebral cortex of five out of seven cases which had been diagnosed pathologically as PSP. The identification of AN was greatly facilitated by the use of neurofilament immunohistochemistry. The entorhinal and transentorhinal cortices were most frequently involved, but in several cases AN were also seen throughout the neocortex. The presence and number of AN roughly correlated with a history of clinical dementia. This suggests that cortical AN may be a common and important pathological finding in PSP.

Distribution of tangles and threads in the cerebral cortex in progressive supranuclear palsy

Recent studies have described silver- and tau-positive glia and threads in the degenerating lesions of progressive supranuclear palsy. In this study, Gallyas-Braak silver impregnation and several immunohistochemical techniques were employed to examine the distribution of tangles, abnormal glia and threads in the cerebral cortex of nine cases of progressive supranuclear palsy. In addition to neurofibrillary tangles, argentophilic glia and threads were impregnated exclusively by Gallyas-Braak technique. This technique demonstrated two types of glia profiles: tightly coiled intra-cytoplasmic profiles surrounding nuclei (coiled profiles) and thorn-like profiles with radial ramifications (thorn-like profiles). Thorn-like profiles are possibly in astrocytes and were detected in the cerebral cortex, while coiled profiles are possibly in oligodendroglia and were detected both in the cerebral cortex and subcortical white matter. Topographically, many neurofibrillary tangles were constantly seen in the frontal cortex and in the pre-central gyrus. Numerous neurofibrillary tangles were detected in the entorhinal cortex of the two brains. Argentophilic glia and threads were also frequent both in the frontal cortex and the precentral gyrus; however, they were more frequent in the pre-central gyrus that in the frontal cortex in four of the eight cases examined. In two brains, argentophilic threads were distributed widely in the cerebral cortex and white matter except for the temporal cortex. In immunohistochemical studies, argentophilic glia and threads were mostly positive for Tau 2, and a small number of them were weakly positive for ubiquitin and paired helical filament protein. The immunoproperties of these abnormal glia and threads seemed to be virtually identical to those of neurofibrillary tangles.(ABSTRACT TRUNCATED AT 250 WORDS)

Paired helical filaments and straight tubules in astrocytes: an electron microscopic study in dementia of the Alzheimer type

Ultrastructural investigation of the hippocampal CA1 and CA4 of nine autopsy-proven cases of dementia of the Alzheimer type (duration of disease: 3-16 years; age: 76-92 years) revealed paired helical filaments (PHFs) and straight tubules (STs) in astrocytes of three advanced cases of long duration (> 13 years). The PHFs and STs were indistinguishable from those seen in neurons. The abnormal glial fibrils were confined to the astrocytic processes that were associated with small vessels or, more frequently, with ghost tangles. In both locations the astrocytic PHFs and STs were located in the cytoplasm without limiting membranes, and were thicker than the straight filaments that composed ghost tangles. These findings, combined with the presence of regular constrictions of astrocytic PHFs, suggest that abnormal astrocytic fibers are produced by the glial cells, not engulfed by them. In addition, the presence of these abnormal glial filaments in only advanced, long-duration cases of dementia of the Alzheimer type suggests that disease duration has a significant effect upon the formation of these astrocytic profiles.

Pick's disease immunohistochemistry: new alterations and Alzheimer's disease comparisons

Pick's disease (PD) brains were examined immunohistochemically for the expression of antigens known to be associated with Alzheimer's disease (AD) lesions. Most antibodies which label intracellular neurofibrillary tangles (NFTs) in AD were found to stain Pick bodies (PBs). Among them was the monoclonal antibody A2B5, which is known to recognize neuronal surface gangliosides. This result indicates that membrane proteins are probably incorporated into PBs as into NFTs. However, PBs, in contrast to NFTs, showed a paucity of staining for heparan sulfate glycosaminoglycan and basic fibroblast growth factor (bFGF). Staining for midkine, seen in senile plaques in AD, was not seen in PD. The relative lack of staining for these two neurotrophic factors in PD brain may reflect underlying mechanisms which are distinct from those in AD. We also describe two glial abnormalities in PD: glial fibrillary tangles and clusters of granules positive for the complement protein C4d in the hippocampal dentate fascia. These are presumably related to complement-activated oligodendroglia, and both pathological structures are more abundant in advanced cases, suggesting that they may be hallmarks of the disease progression.

Astrocytic straight tubules in the brain of a patient with Pick's disease

This report concerns an immunohistochemical and ultrastructural study of cerebral astrocytes in a patient with Pick's disease of 20 years' duration. The autopsied brain was prominently small (710 g) with marked fronto-temporal lobar atrophy. Histological examination demonstrated profound neuronal loss and spongy changes with tau-positive Pick bodies in the frontal and temporal cortex. In addition, many glial cells in the temporal lobe white matter contained round to oval, argentophilic and slightly hematoxinophilic cytoplasmic inclusions that were also immunolabeled with the anti-tau antibody. On electron microscopy, the glial inclusions were observed in the perikarya of astrocytes that were recognized as such from intracytoplasmic glial filaments and the presence of gap junctions. The inclusions were free in the cytoplasm, without a limiting membrane, and mainly comprised irregular aggregations of bundles of about 15-nm straight tubules, which were indistinguishable from those of intraneuronal Pick bodies. Furthermore, various patterns of accumulation of the same straight tubules were frequently noted in perivascular astrocytic processes carrying a basal lamina. These findings indicate that in Pick's disease astrocytes are also affected by a similar insult to that which affects neurons.

Unusual case of corticobasal degeneration with tau/Gallyas-positive neuronal and glial tangles

A 74-year-old woman with corticobasal degeneration (CBD) had a 9-year history of progressive loss of strength and rigidity of her right hand and then arm, followed by speech difficulties, dyskinesia, rigidity, spasticity and weakness of the ipsilateral lower limb, ultimately also involving the opposite side. She later developed supranuclear gaze palsy. Her memory remained intact during most of the duration of her disease. Laboratory tests and anti-Parkinsonian medications were not helpful. At autopsy, frontal lobe atrophy, discoloration of putamen (Pt) and pallor of substantia nigra (Sn) were observed. Neuronal loss and gliosis were extensive in motor cortex and milder in frontal cortex, abruptly ending at the central sulcus and junction of cingulate gyrus. "Achromatic" neurons were present. Neuronal loss and gliosis were seen in Pt and Sn and corticobasal inclusions in Sn. Numerous Gallyas/tau-positive, Bielschowsky/ubiquitin-negative coil, sickle, or coma-shaped tangles and thread-like processes were found in affected cortex, Pt and Sn. Some of the tangles were in neurons, but most occurred in astroglia, and their processes. The presence of Gallyas/tau-positive glia in CBD may have the same diagnostic significance as in progressive supranuclear palsy, analogous to the argyrophilic ubiquinated inclusions in oligodendroglia in multisystem atrophy. We suggest that in CBD: (1) cytoskeletal protein metabolism in neurons and glia can simultaneously be perturbed in certain neurodegenerative diseases, and (2) the astrocytosis in CBD may not be simply a reactive process but an integral part of the disease.

Corticobasal degeneration: a disease with widespread appearance of abnormal tau and neurofibrillary tangles, and its relation to progressive supranuclear palsy

The neuropathological findings, including immunohistochemistry and electron microscopy, of two patients with clinical findings consistent with corticobasal degeneration (CBD) are reported. Both patients showed degeneration of the precentral cortex, the substantia nigra, the pallidum, and the thalamus. Many ballooned neurons were seen in the cerebral cortex, and argentophilic, skein-like inclusions suggesting neurofibrillary tangles (NFTs) were found in the brain stem and precentral cortex in patient 1. In contrast, patient 2 clearly showed NFTs in the brain stem and dentate nucleus which were indistinguishable from those seen in progressive supranuclear palsy (PSP), while only a few ballooned neurons were found in the cerebral cortex. Gallyas silver stain showed many argentophilic inclusions suggesting NFTs in the brain stem, subcortical nuclei, and cerebral cortex in both patients. Immunohistochemistry for tau showed tau-positive neurons in the cerebral cortex, brain stem, subcortical nuclei and spinal cord, and tau-positive glial cells were seen in the cerebral cortex, white matter and subcortical nuclei, and thread-like structures were seen in the cerebral cortex and white matter. Electron microscopy of the brain stem showed NFTs consisting of paired helical filaments in patient 1, and paired helical filaments and straight tubules in patient 2. Immunoelectron microscopy revealed parallel tau-positive filaments in the cerebral cortex in patient 1. From the two patients, the wide-spread appearance of abnormal tau and NFTs is one of the essential pathological features in CBD, and it also appears that CBD and PSP have some common underlying pathological processes. Patient 2 is closer to PSP than patient 1 and suggests CBD would link to PSP.

Neuronal and glial tau-positive inclusions in diverse neurologic diseases share common phosphorylation characteristics

Tau accumulating as paired helical filaments (PHF) in Alzheimer's disease brain is considered to be abnormally phosphorylated on distinct sites. To compare the phosphorylation state of tau-positive neuronal inclusions among diverse neurologic diseases, we have probed these lesions with three well-defined PHF/tau monoclonals, C5, M4 and tau 1, that most likely recognize three proline-directed phosphorylation sites in PHF-tau. In Alzheimer's disease brain all three monoclonals intensely immunostained intracellular neurofibrillary tangles, neuropil threads, senile plaque neurites, and "pretangle neurons" in a phosphorylation-dependent manner. They also stained, in the same manner, Pick bodies in Pick's disease, and neurofibrillary tangles and neuropil threads in various tangle-forming neurologic diseases. In most of these diseases (including Pick's disease, progressive supranuclear palsy, subacute sclerosing panencephalitis, and Alzheimer's disease) astrocytes and oligodendrocytes were found to contain tau-positive inclusions which showed the same immunocytochemical characteristics. Thus, the widely occurring tau-positive inclusions share common phosphorylation characteristics irrespective of underlying diseases or cell types.

Corticobasal degeneration: etiopathological significance of the cytoskeletal alterations

We have studied brain tissues from three patients with corticobasal degeneration (CBD) histologically, ultrastructurally and immunohistochemically. Ballooned neurons in the cerebral cortex and severe degeneration of the substantia nigra were observed in them all and weakly basophilic neurofibrillary tangles (NFTs) were distributed widely in the basal ganglia and brain stem. Ultrastructural examination demonstrated that the NFTs comprised characteristic 15-nm-wide straight tubules, which showed positive immunohistochemical staining with an antibody against tau, but not ubiquitin. Tau-immunoreactive neuronal cell bodies without NFTs also were found in the cerebral cortex and subcortical nuclei, predominantly in the brain stem, and the greatest number of tau-positive glial inclusions occurred in the cerebral gray and white matter of the pre- and post-central gyri. These inclusions comprised tubular structures with diameters of about 15 nm and were localized in the oligodendroglial cellular cytoplasm and processes. These findings indicate that there is a close cytoskeletal pathological relationship between CBD and progressive supranuclear palsy.

Synaptophysin and chromogranin A immunoreactivities of Lewy bodies in Parkinson's disease brains

Lewy bodies commonly observed in brains with Parkinson's disease (PD) histochemically contain both protein and lipid as chemical components. Ultrastructurally, they are composed of filamentous, vesicular and granular structures. We investigated PD brains with light and electron microscopic immunohistochemistry using antibodies against two marker proteins for neuronal secretory vesicles, synaptophysin and chromogranin A. Both antibodies immunolabeled the peripheral zones and occasionally central cores of Lewy bodies of the classical and intraneuritic types. In addition, the diffuse immunolabeling was observed in Lewy bodies of the cortical type. Furthermore, the ultrastructural immuno-decoration was found mainly in the vesicular structures, and also in the filamentous and granular structures of Lewy bodies. Immuno-blot analysis of each antibody showed no difference between PD and normal control brains. The present observations suggest that vesicular profiles of Lewy bodies represent presynaptic and dense core secretory vesicles, and therefore that the lipid elements of Lewy bodies are derived from membrane lipids of these vesicles.

Cortical tangles in progressive supranuclear palsy

Ten cases of PSP were examined for the presence of neocortical and hippocampal lesions. Samples from 10 cortical areas were stained by Bodian's method and by tau, ubiquitin and beta A4 immunocytochemistry. For the sake of comparison, 5 Alzheimer's cases were studied with the same techniques. Neocortical tangles, star-like tufts of fibers, and neuropil threads were seen in all the cases of PSP. They were stained by Bodian's technique and labelled by an anti-tau, but not by a polyclonal anti-ubiquitin antibody. Senile plaques (Bodian's technique), diffuse or focal amyloid deposits (beta-A4 immunohistochemistry) were rare or absent. The density of tangles was the highest in area 4 and the lowest in area 17. In area 4, the tangles were mainly located in layers V-VI. By contrast, the Alzheimer's tangles had a bimodal distribution (layers III and V-VI). These results favor the specificity of cortical alterations in PSP.

Anti-tau-positive glial fibrillary tangles in the brain of postencephalitic parkinsonism of Economo type

Tau-immunoreactive astrocytes have been reported in the brain of progressive supranuclear palsy (PSP) and are referred to as glial fibrillary tangles (GFTs). We found a number of GFTs in the heavily degenerated brain region in four cases of postencephalitic parkinsonism of Economo (PPE) with a clinical history of over a half-century. GFTs had the appearance of tufts of spider-like radiating fibers or small thorn-like feature by Gallyas-Braak method and also by anti-tau immunostaining.

Neurofibrillary tangles in the neurons of spinal dorsal root ganglia of patients with progressive supranuclear palsy

Neurofibrillary tangles (NFTs) occur in neurons of human central nervous system (CNS) both in aged subjects and patients with several degenerative diseases, with a certain topographical predilection. In surveying the NFT distribution in nervous tissue of patients with progressive supranuclear palsy (PSP), we found silver-positive fibrillary tangles in the neurons of dorsal root ganglia (DRG) in two of five patients. By immunohistochemistry, these tangles were stained with antibodies to human tau protein, paired helical filaments (PHFs) and ubiquitin. Electron microscopy revealed that they were mainly composed of PHFs that were morphologically indistinguishable from PHFs in the NFTs of CNS typically seen in Alzheimer's disease brains. Our data demonstrate for the first time that the neurons of DRG produce NFTs in PSP and suggest that the pathological process(es) leading to tangle formation can occur in the neurons of the peripheral nervous system in this disease condition.