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Biomedical subjects

Yasuo Iwasaki

Publications and source records attributed to Yasuo Iwasaki.

At least 19 recordsLinked to original sources
PubMed2006

Adult moyamoya disease in the asymptomatic Japanese population.

Moyamoya disease (MMD) is a spontaneous occlusive disease of the Willis circle. This study evaluated the presence of the radiological hallmarks of adult MMD on a "brain check-up" (BC) using MRI and MR angiography, in Japan. BC was offered to 11,402 healthy subjects (7570 men and 3832 women) between January 1997 and November 2003. The mean age of all subjects was 53.2 years (SD 11.1); the mean age of men was 53.2 years (SD 10.9) and women 53.2 years (SD 11.5). MMD was diagnosed according to the criteria of the Research Committee on Spontaneous Occlusion of the Circle of Willis in Japan. Eight subjects (4 men and 4 women) were diagnosed as probable MMD without neurological deficits. Thus, the percentage of subjects with asymptomatic MMD on BC was 0.07% for the total group, 0.05% in men and 0.10% in women. The female to male ratio was 3.3:1. The mean age of the MMD patients was 54.0 years (SD 12.0); men 54.8 years (SD 12.8) and women 53.3 years (SD 13.9). Estimates of the prevalence of MMD in the Japanese population were calculated as 50.7 per 100,000 people; 28.9 in men and 94.3 in women. Five patients had a family history of definite MMD and seven had a family history of subarachnoid or intracerebral hemorrhage. MRI and angiography showed stenosis of the bilateral internal carotid arteries (ICA) in five patients and a unilateral ICA in three. Moyamoya vessels were confirmed on cerebral angiography. Our standard BC protocol is limited for the detection of moyamoya vessels in the initial stages of MMD. The present study suggests that the radiological features of MMD are asymptomatic in the early stages of the disease.

Adult↗
PubMed2006

Spinal chronic subdural hematoma in association with anticoagulant therapy: a case report and literature review.

STUDY DESIGN: A case of spinal chronic subdural hematoma (SCSDH) in association with anticoagulant therapy was treated surgically. OBJECTIVE: To clarify the etiopathogenesis, clinical presentation, and surgical outcomes of SCSDH. SUMMARY OF BACKGROUND DATA: Intracranial chronic subdural hematoma is a well-recognized complication of anticoagulant therapy. However, SCSDH is very rare and its etiopathogenesis is uncertain. METHODS: A 72-year-old man with SCSDH who had received anticoagulant therapy for atrial fibrillation complained of bilateral lower extremity pain, cramps, and gait disturbance. The patient underwent an operation for evacuation of the hematoma. RESULTS: Lower-extremity pain, cramps, and gait disturbance improved, and the patient was discharged 10 days after surgery. CONCLUSION: SCSDH should be included in the differential diagnosis of progressive spinal cord and nerve root compression in patients receiving anticoagulant therapy. Prompt diagnosis and early surgical decompression lead to a good outcome.

Aged↗
PubMed2005

Cheiro-oral-pedal syndrome due to brainstem hemorrhage.

Cheiro-oral-pedal syndrome is characterized by specific sensory disturbance around the corner of the mouth, in the hand and in the foot on the same side. Lesions responsible for causing this syndrome vary. We report two cases of cheiro-oral-pedal syndrome due to midbrain and pontine hemorrhage, respectively. Pontine hemorrhage producing cheiro-oral-pedal syndrome has been reported in three cases, but this is the first case that midbrain hematoma exhibits this syndrome. Damage in the sensory pathway can cause cheiro-oral-pedal syndrome. Difference in the threshold may explain the specific sensory pattern in this syndrome. Cheiro-oral-pedal syndrome is caused by lacunar infarction in majority of the cases. However, it should be kept in mind that hematomas can cause cheiro-oral-pedal syndrome.

Cerebral Hemorrhage↗
PubMed2005

Cheiro-pedal syndrome following pontine infarction.

We report the case of a 64-year-old man with sudden onset of numbness in the right hand and foot. Neurological examinations were normal except for hypersthesia, and hyperalgesia of the right hand and foot. Brain MRI demonstrated a high signal intensity on T2-weighted image and a low signal intensity on T1-weighted image in the left tegmetum of the pons. He was diagnosed with pontine infarction presenting with cheiro-pedal syndrome (CPS). Damage in the sensory pathways can cause CPS. Difference in the threshold may explain the specific sensory pattern in this syndrome. Further examination of the relationship between sensory symptoms and localization on MRI is needed to clarify this syndrome.

Brain Stem Infarctions↗
PubMed2004

Autosomal dominant childhood onset slowly progressive leukodystrophy--a Japanese family with spastic paraparesis, ataxia, mental deterioration, and skeletal abnormality.

Autosomal dominant leukodystrophy is an extremely rare disease. Here we report on a dominantly inherited disease in a Japanese family with slowly progressive clinical course. Their symptoms and signs started in early childhood and very slowly progressed. In most patients spastic gait was the initial symptom. Neurological manifestations were characterized by pyramidal signs, ataxia, and mental deterioration. In addition to these neurological signs, the skeletal anomalies such as scoliosis and congenital hip dislocation were also present. MR images showed no abnormality in the early stage, but T2-weighted images revealed high intensity areas in the cerebral and cerebellar white matter, and the dentate nucleus in the advanced stage. Proton MR spectroscopy showed decrease of N-acetylaspartate/creatine ratio and increase of choline/creatine ratio in the advanced stage. Proton MR spectroscopy revealed normal N-acetylaspartate/creatine ratio and increase of choline/creatine ratio in the early stage. We suggested that these patients had abnormality in the white matter when MRI was still normal. We considered that intracranial demyelination was gradually progressed as the symptoms got aggravated.

Adolescent↗