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Biomedical subjects

A Tamaoka

Publications and source records attributed to A Tamaoka.

At least 37 records · Page 2Linked to original sources
PubMed1999

Alzheimer's disease: correlation of the suppression of beta-amyloid peptide secretion from cultured cells with inhibition of the chymotrypsin-like activity of the proteasome.

Peptide aldehyde inhibitors of the chymotrypsin-like activity of the proteasome (CLIP) such as N-acetyl-Leu-Leu-Nle-H (or ALLN) have been shown previously to inhibit the secretion of beta-amyloid peptide (A beta) from cells. To evaluate more fully the role of the proteasome in this process, we have tested the effects on A beta formation of a much wider range of peptide-based inhibitors of CLIP than published previously. The inhibitors tested included several peptide boronates, some of which proved to be the most potent peptide-based inhibitors of beta-amyloid production reported so far. We found that the ability of the peptide aldehyde and boronate inhibitors to suppress A beta formation from cells correlated extremely well with their potency as CLIP inhibitors. Thus, we conclude that the proteasome may be involved either directly or indirectly in A beta formation.

Aldehydes↗
PubMed1999

[A case of delayed cerebral infarction occurring in puerperium preceded by herpes zoster ophthalmicus in late pregnancy].

Delayed central neurological symptoms following herpes zoster ophthalmicus (HZO) such as "herpes zoster ophthalmicus and delayed contralateral hemiparesis" are considered to be due to ipsilateral intracranial vasculopathy. We experienced a rare case with cerebral infarction occurred in puerperium following HZO in late pregnancy. A healthy 30-year-old woman had left HZO at weeks 35 of gestation. She was given acyclovir (ACV) for external use and improved with small pigmentation on the left eye-lid. Seven weeks after the onset of HZO, she suddenly developed aphasia and right hemiparesis. Cerebral angiogram showed narrowing on M 1 segment of the ipsilateral middle cerebral artery. The occlusion was seen on peripheral portion of the angular artery on the same side. In cerebrospinal fluid (CSF), cell count was slightly elevated, but concentration of protein and sugar were normal. Varicella-zoster titer was increased in both serum and CSF. She was treated with intravenous ACV (1500 mg/day) for 10 days. On the next day after the treatment, the cell count was normalized and on 18th day, varicella-zoster titer was decreased in CSF. Higher brain function improved and no relapses occurred. This is a first case of delayed cerebral infarction occurring in puerperium preceded by herpes zoster ophthalmicus in late pregnancy, as far as we searched. We should treat carefully pregnant or lactating patients with HZO, considering delayed cerebral infarction.

Acyclovir↗
PubMed1999

A combination of autoimmune hepatitis, sensory-dominant peripheral neuropathy, and primary Sjögren's syndrome in the same patient: a rare association.

Although autoimmune hepatitis and sensory-dominant neuropathy have been known to independently accompany primary Sjögren's syndrome, the combination of all these conditions in the same patient has not been described. We report the case of a woman who initially suffered from autoimmune hepatitis and later was diagnosed with primary Sjogren's syndrome upon the development of sensory-dominant neuropathy. In this patient, autoimmune hepatitis preceded neuropathy by one year. All of the diagnoses were confirmed by histological examinations of the liver, sural nerve, and minor salivary gland. Her autoimmune hepatitis was relieved with conservative treatment, and her sensory-dominant neuropathy was alleviated by prednisolone therapy. Our case indicated that the multiple organ involvement, especially that in the liver and peripheral nerves, should be taken into account in the course of primary Sjögren's syndrome.

Anti-Infective Agents↗
PubMed1999

[A case of stiff-man syndrome with head retraction like reflex myoclonus and jerky myoclonus of bilateral lower extremities which responded well to removal of mediastinal carcinoma].

A 58-year-old male presented with reflex myoclonus and stiffness of the left facial, tongue, shoulder, and lower limbs muscles. Muscle stiffness and gait progressively worsened, leading to frequent falls. Acoustic and cutaneous stimuli of head precipitated reflex myoclonus like head retraction. Cutaneous of lower extremities precipitated jerky myoclonus of bilateral lower extremities. CSF analysis were unremarkable. No anti GAD antibody or anti amphiphysin antibody was detected in the serum and CSF. On surface EMG the spasms initiated with 4-5 short burst discharges at intervals between 59 and 84 ms, followed by a tonic decrescendo activity up to 3 s. After diazepam treatment, stiffness and reflex myoclonus of lower extremities were disappeared and head retraction like reflex myoclonus was improved but remained. CT of the chest revealed a mediastinal tumor. Biopsy of the tumor revealed undifferential carcinoma. The patient further improved after the resection of the tumor. These findings suggest that this stiff-man syndrome may occur as an autoimmune paraneoplastic syndrome of CNS.

Autoimmunity↗
PubMed1998

Downbeat nystagmus in two siblings with spinocerebellar ataxia type 6 (SCA 6).

We report two siblings with spinocerebellar ataxia type 6 (SCA 6), both showing downbeat nystagmus (DBN) as a predominant clinical feature. Familial hemiplegic migraine (FHM), episodic ataxia type 2 (EA-2) and SCA 6 are allelic disorders, and interestingly, the occasional presence of DBN in EA-2 was reported. Our observations suggest that common molecular mechanisms might underlie DBN in FHM, EA-2 and SCA 6. Then, these disorders should be kept in mind in diagnosing patients with DBN.

Adult↗
PubMed1998

Emergence of immunoreactivities for phosphorylated tau and amyloid-beta protein in chronic stage of fluid percussion injury in rat brain.

Head injury is one of the potential environmental factors in Alzheimer's disease (AD). To study the chronic stage of concussive brain injury, histological analyses were performed 2-6 months after right lateral fluid percussion (FP) brain injury (3.6-4.8 atm) in rats. Six months after injury, numerous normal-looking neurons in the telencephalon and brain stem were immunoreactive with either antibody to phosphorylated tau or with four antibodies to beta-amyloid protein. Neuronal counts in the cortices were gradually decreased after injury, up to 42% loss at 6 months after injury. These neuropathological changes suggest that this animal model could serve as a good animal model of neurodegenerative diseases such as AD.

Amyloid beta-Peptides↗
PubMed1998

Horner's syndrome associated with mononeuritis multiplex due to cytomegalovirus as the initial manifestation in a patient with AIDS.

We report on a 60-year-old male with AIDS who presented Horner's syndrome that was associated with mononeuritis multiplex due to cytomegalovirus (CMV) infection. This is the first case who presented Homer's syndrome in the course of AIDS. Horner's syndrome associated with mononeuritis multiplex in this patient was the initial manifestation without any opportunistic infections. Since Horner's syndrome and mononeuritis multiplex in the present case were both improved by ganciclovir, it is important to consider CMV infection when Horner's syndrome or mononeuritis multiplex is observed in immunocompromised patients, such as those with HIV-1 infection or AIDS, even if they do not show any other opportunistic infections.

AIDS-Related Opportunistic Infections↗
PubMed1998

Amyloid-beta-protein isoforms in brain of subjects with PS1-linked, beta APP-linked and sporadic Alzheimer disease.

To determine whether similar abnormalities of various soluble full-length and N-terminal truncated Abeta peptides occur in postmortem cerebral cortex of affected PS1 mutation carriers, we examined the amounts of two amyloid species ending at residue 40 or at residues 42(43) using sandwich ELISA systems. Our results indicate that PS1 mutations effect a dramatic accumulation in brain of the highly insoluble potentially neurotoxic long-tailed isoforms of the Abeta peptide such as Abeta1-42(43) and Abetax-42(43). This enhancing effect of PS1 mutation on Abetax-42(43) deposition was highly similar to that of a betaAPP mutation (Val717Ile) but the effects on Abetax-40 production were significantly different between these two causal genes. In contrast to previous studies of soluble Abeta in plasma and in supernatants from cultured fibroblasts of subjects with PS1 mutations, our studies also show that there is an increase in insoluble Abetax-40 peptides in brain of subjects with PS1 mutations.

Adult↗
PubMed1998

[Characterization of amyloid beta protein species in the plasma, cerebrospinal fluid and brains of patients with Alzheimer's disease].

Extracellular deposition of amyloid beta protein (A beta) as senile plaques and cerebral amyloid angiopathy (CAA) is one of the essential pathological characteristics of Alzheimer's disease (AD). Several A beta species with different carboxyl termini, including A beta 42 (43) and A beta 40 ending at residue 42 (43) and 40, respectively, have been identified in CAA and in senile plaque cores. Because A beta 42 (43), the major component of diffuse plaque which is the earliest pathological change in AD brains, forms insoluble amyloid fibrils more rapidly than does A beta 40, it has been hypothesized that A beta 42 (43) plays a role in amyloid seeding and A beta 40, in the elongation of amyloid fibrils on a seed of A beta 42 (43). We used enzyme-linked immunosorbent assay (ELISA) with site-specific monoclonal antibodies to differentiate A beta 42 (43) from A beta 40. First, we measured the amounts of different A beta species in plasma from patients with sporadic probable AD, age-matched patients with neurologic diseases but without dementia, and age-matched normal controls. Concentrations of A beta 1-40 and A beta 1-42 (43) in plasma did not differ significantly among the three groups. Second, CSF levels of A beta species (CSF-A beta) with different carboxy termini, i.e., A beta X-40 and A beta X-42 (43) as well as A beta 1-40 and A beta 1-42 (43), were measured in patients with AD and in age-matched controls without dementia using ELISA. Levels of both CSF-A beta X-42 (43) and A beta 1-42 (43) were significantly lower in the patients with AD that in the controls, but neither the levels of CSF-A beta X-40 nor those of CSF-A beta 1-40 differed between the two groups, which suggest that increased adsorption of A beta 42 (43) to A beta deposition in AD brains, decreased secretion of A beta 42 (43) in CSF, or increased clearance of A beta 42 (43) from CSF might explain the low levels of A beta 42 (43) in the CSF of patients with AD. Third, we measured the concentrations of various A beta species post-mortem in the cerebral cortex of patients with PS-1 mutations and beta amyloid precursor protein (APP) 717 mutation linked to familial AD or Down syndrome. The results indicate that one effect of PS-1 mutations, APP717 mutation and Down syndrome is to cause dramatic and accelerated accumulation of A beta 42 (43) in the brain as compared with sporadic AD. In particular, the increases in A beta 1-42 (43) showed a crude inverse correlation with the age of onset in each subtype of AD. Thus, quantitative studies differentiating A beta 42 (43) from A beta 40 have established the fundamental importance of A beta 42 (43) in AD.

Alzheimer Disease↗
PubMed1998

[A case of livedo vasculitis associated with mononeuritis multiplex].

Livedo vasculitis is characterized by recurrent livedo reticularis of lower extremities and the histopathological findings of segmental hyalinizing vasculitis in the skin. We report a case of a 26-year-old female who manifested mononeuritis multiplex 7 years after the onset of livedo vasculitis. She showed sensori-motor disturbances in the right median and ulnar nerves and sensory deficits of the bilateral peroneal nerves. Sural nerve biopsy revealed a remarkable loss of large and small myelinated fibers and a few vasculitic changes. Steroids therapy was effective for these neurological symptoms. But paroxysmal numbness appeared later recurrently in the regions of affected nerves with painful ulcerations in the right leg. Laboratory tests indicated increased levels of serum thrombin-antithrombin complex (TAT), and antithrombotic drugs (argatroban) remarkably ameliorated the recurrent symptoms and skin lesions. These findings suggest that the pathogenesis of livedo vasculitis might be related to alterations of the blood coagulation system.

Adult↗
PubMed1998

Quantitation of amyloid beta-protein (A beta) in the cortex during aging and in Alzheimer's disease.

In this study we sought to learn about when and how amyloid beta-protein (A beta) accumulates in the cortex of normal individuals and about the difference in the A beta accumulation between normal aged and Alzheimer's disease (AD) brains. From consecutive autopsy cases and AD cases, hippocampus CA1 and occipitotemporal cortex T4 were sampled for A beta quantitation by the well characterized two-site enzyme immunoassays (EIAs). There was a strong tendency toward A beta 42 accumulation between the ages of 50 and 70 years in T4 and a little later in CA1. The A beta 42 levels were consistently higher in T4 than those in CA1 in any given case. The levels of A beta 42 in AD brains were significantly higher than those in control brains, and the extent of A beta 42 amino-terminal modification was also much greater in AD brains than that in control brains. Even in cases in which no senile plaques were immunocytochemically detected, EIAs clearly showed that significant amounts of A beta 42 already had accumulated. In contrast to A beta 42, A beta 40 showed no apparent age-dependent accumulation, and its high levels were found to be associated with AD.

Adult↗
PubMed1998

[A case of hypertrophic cranial pachymeningitis associated with intramedullary lesion developed seizure marching from right lower extremity].

A case of hypertrophic cranial pachymeningitis associated with intramedullary lesion was reported. A 57-year-old male presented with the symptoms of Jacksonian seizure and weakness of right lower extremity. Neurological examination showed weakness and muscular atrophy of right lower extremity (MMT 1-2) and hyperreflexia. Superficial sensation and position sense were normal, however cortical sensory disturbance was recognized in his right lower extremity. MRI revealed diffuse dural thickening with gadolinium enhancement in the left convexity and hyperintense lesion in the bilateral (left dominant) frontal to parietal lobe on T2 weighted image. Magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) showed occlusion of the superior sagittal sinus. Histological examination revealed extensive fibrous tissue with lymphocytes infiltration around the vessels. The cause of the intramedullary lesion in this patient may have been related to the occlusion of superior sagittal sinus, due to thickening dura mater and influence of inflammation.

Angiography, Digital Subtraction↗