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Biomedical subjects

Takahiro Iizuka

Publications and source records attributed to Takahiro Iizuka.

12 recordsLinked to original sources
PubMed2006

Familial reducing body myopathy.

Reducing body myopathy (RBM) is a rare pathologically defined myopathy characterized by the presence of inclusion bodies which are abnormally stained by menadione-nitroblue-tetrazolium. The clinical symptoms vary widely as to the age of onset, disease progression and severity. Among the many reported patients, there have been only three families with this disorder, showing a manifold of clinicopathological features in each family. We report a fourth family with RBM affecting a boy and his mother. The proband (boy) began to have difficulty putting on his trousers at age 10years and difficulty arising from a chair at 11years. His spine was rigid. His mother, on the other hand, noticed foot-drop at the age 29, but the clinical course was rapidly progressive, and she was wheelchair-bound at 34years. Both patients had generalized muscle weakness and atrophy and with mild CK elevation. Muscle pathology was characterized by the presence of atrophic fibers with reducing bodies in some areas. As these patients demonstrate, clinical symptoms in RBM are very variable, even within the same family. There are no specific clinical characteristics distinctive to RBM, thus further studies are necessary to characterize this disorder both clinically and pathologically.

Adult↗
PubMed2006

[Diagnostic criteria of neurosarcoidosis].

We have collaborated with Japanese Sarcoidosis Society and Japanese Society of Respiratory Disease to provide a new diagnostic criteria of neurosarcoidosis. At least two of six examinations are important. These include bilateral hilar lymphadenopathy, abnormal uptake of 67Ga scintigraphy, broncho alveolar lavage fluid examination, elevated serum ACE, negative tuberculin reaction, and elevated serum or urinary calcium level. (definite) Having positive clinical findings which suggest a neurosarcoidosis. Pathology proven case. (probable) Having positive clinical findings which suggest a neurosarcoidosis. Pathology proven in other organ. At least two of six examinations are positive. (possible) Having positive clinical findings which suggest a neurosarcoidosis. At least two of six examinations are positive. CNS sarcoidosis, sarcoid neuroopathy and sarcoid myopathy are separately diagnosed. Kveim reaction which is time consuming, not so specific, and difficult to obtain its antigen is no more necessary.

Central Nervous System Diseases↗
PubMed2005

Pathogenesis of stroke-like episodes in MELAS: analysis of neurovascular cellular mechanisms.

The pathogenesis of stroke-like episodes in mitochondrial encephalopathy, myopathy, lactic acidosis and stroke-like episodes (MELAS) is not fully understood although two main theories have been proposed; ischemic vascular hypothesis caused by "mitochondrial angiopathy" and generalized cytopathic hypothesis caused by "mitochondrial cytopathy". Crucial molecular mechanism includes the lack of taurine modification at the wobble uridine of mutant transfer RNAsLeu(UUR) resulting in defective translation of cognate codons due to a defect in codon-anticodon interaction. Whereas recent clinical studies have shed light on the neuronal hyperexcitability, which may potentially initiate a cascade of stroke-like events. Stroke-like episodes are characterized by neuronal hyperexcitability, neuronal vulnerability, increased capillary permeability, and focal hyperaemia. It is recognized that stroke-like lesions not only evolve in the area incongruent to a vascular territory, but also potentially spread into the surrounding cortex with concomitant vasogenic edema presumably provoked by prolonged epileptic activities. Based on the clinical observations, we speculate that stroke-like episodes appear to be non-ischemic neurovascular events; once neuronal hyperexcitability developed in a localized brain region as a result from either mitochondrial dysfunction in the capillary endothelial cells, or in neurons or astrocytes, epileptic activities may depolarize the adjacent neurons leading to propagation of epileptic activities in the surrounding cortex. Increased capillary permeability provoked by epileptic activities in the presence of mitochondrial capillary angiopathy may cause unique edematous brain lesions predominantly involving the cortex. As a consequence, susceptible neuronal population in the cortex may result in neuronal loss with a laminar or pseudo-laminar distribution.

Blood Vessels↗
PubMed2005

[Prophylactic treatment with botulinum toxin type A].

Migraine is a common neurological disorder, characterized by recurrent attacks of severe headache. Its prevalence is estimated 8.4% of general population in Japan. Acute migraine treatment has dramatically improved with the development of a novel class of selective 5-HT1B/1D/1F receptor agonists, known as the triptans, but prophylactic treatment still remains limited. Botulinum toxin type A(BoNT-A) has recently been shown to be effective in randomized control trials, but no prospective study has been conducted yet in Japan. In this paper, we review the results of recently published controlled trials, touching on its methodology, optimal dose, patient selection, and possible mechanisms, as well as on going clinical trial in our university.

Botulinum Toxins, Type A↗
PubMed2005

[Diagnostic criteria of neurosarcoidosis].

We have collaborated with Japanese Sarcoidosis Society and Japanese Society of Respiratory diseases to make a new diagnostic criteria of neurosarcoidosis. (definite) Having positive clinical findings which suggest a neurosarcoidosis. Pathology proven case. (probable) Having positive clinical findings which suggest a neurosarcoidosis. Pathology proven in other organ. Elevated serum ACE or BHL demonstrated by chest XP or CT scan. (possible) Having positive clinical findings which suggest a neurosarcoidosis. Elevated serum ACE or BHL demonstrated by chest XP or CT scan. CNS sarcoidosis, sarcoid neuropathy and sarcoid myopathy are separately diagnosed. To evaluate our criteria, about 100 papers on neurosarcoidosis published worldwide in these 6 years were retrospectively examined. Our criteria showed a better results than 1988 criteria (former Japanese criteria) and Zajicek's criteria which was published in 1999 (QJ Med 92: 103). Point is there is no more need to depend upon Kveim reaction which is time consuming, not so specific and difficult to obtain its antigen. Our new criteria is calculated to be sensitivity of 78-98% (BHL or ACE), and specificity of 83-99% (ACE). Because of their low specificity, Gallium scintigraphy and broncho alveolar lavage fluid examination are excluded from our diagnostic criteria, however, their high sensitivity are still useful to begin with.

Central Nervous System Diseases↗
PubMed2003

Slowly progressive spread of the stroke-like lesions in MELAS.

BACKGROUND: Little is known about temporal and spatial progression of the stroke-like lesion during the acute stage of the stroke-like episode in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). METHODS: In four stroke-like episodes of MELAS observed in three patients, MRI, EEG, and SPECT were studied consecutively within the first month of the onset. RESULTS: The first presenting symptoms were headache in all four stroke-like episodes, followed by hemianopsia, psychosis, and aphasia. In three episodes, epileptic seizure developed subsequently in close association with a progression of stroke-like lesion. In all four episodes, serial MRI showed a slowly progressive spread of the stroke-like lesion evolving from the temporal cortex to the surrounding parietal or occipital cortex over a few weeks following the onset of initial symptoms. Apparent diffusion coefficient (ADC) maps showed slightly decreased ADC values in the actively evolving brain lesions compared with those in nonaffected regions of the brain. EEG showed a pattern of focal periodic epileptiform discharges in three episodes. SPECT showed a focal hyperemia in all four stroke-like lesions, in two of which focal hyperemia persisted for the first month. A T1-weighted hyperintense cortical signal on MRI compatible with cortical laminar necrosis was seen during the subacute stage of all stroke-like lesions. CONCLUSION: Slowly and progressively spreading stroke-like lesions on MRI may reflect ongoing neuronal metabolic derangement associated with concomitant vasogenic edema provoked by prolonged epileptic seizure activities.

Adult↗
PubMed2002

[Neurosarcoidosis].

Sarcoidosis is a chronic systemic disease of unknown causes characterized by noncauseating granuloma in various organs. Neurological involvement occurs in 5-6% of patients with sarcoidosis. Most patients with neurosarcoidosis have extraneurologic abnormalities and extraneurologic biopsies usually support the diagnosis, however, nearly half of the patients with neurosarcoidosis present with neurological manifestations without systemic symptoms. Several cases of isolated neurosarcoidosis have been reported, making the diagnosis difficult. Although several diagnostic criteria have been proposed, neuropathological examination is required for the definite diagnosis. Brain biopsy may still be required in selected patients. Since it is often difficult to perform, clinical assessment with various combinations of modern neuroimaging techniques is important. Lumbar puncture is useful to rule out other diseases but CSF changes are not specific. Elevated serum ACE level is also not a specific diagnosis test. Any part of the CNS can be involved, but there is predilection for hypothalamus, pituitary gland, leptomeninges, and cranial nerves particularly facial nerve. Although corticosteroids are the main stay of therapy, refractory cases can be treated by immunosuppressive and radiation therapy.

Central Nervous System↗
PubMed2002

[Cerebrovascular accidents with familial antithrombin III deficiency--gene analysis study].

We report two cases of the cerebral infarction with familial antithrombin III type I deficiency. Case 1 is a 47-year-old woman presenting deep cerebral vein thrombosis. Case 2 is a 20-year-old man presenting the top of the basilar syndrome. Beside them, substantial number of members had cerebral infarction in this pedigree. We measured AT III activity and quantity for 18 persons in this pedigree. As a consequence, 6 of 18 persons in this pedigree had AT III type I deficiency. Analysis of PCR products of AT III gene derived from the case 1's leukocyte DNA revealed a novel frame shift insertion was demonstrated as mutant alleles with 4-base CTTT in nt 2,420 or nt 2,424 in exon 2 domain on the AT III gene. AT III type I deficiency caused by frame shift insertion has been reported only twelve pedigrees. This is the first case report of AT III type I deficiency caused by frame shift insertion in Japan.

Adult↗