Biomedical subjects

Hiroyuki Nakayasu

Publications and source records attributed to Hiroyuki Nakayasu.

7 recordsLinked to original sources

PubMed2006

Anterior and posterior inferior cerebellar artery infarction with sudden deafness and vertigo.

We report a patient with anterior and posterior inferior cerebellar artery infarction, which manifested as profound deafness, transient vertigo, and minimal cerebellar signs. We suspect that ischaemia of the left internal auditory artery, which originates from the anterior inferior cerebellar artery, caused the deafness and transient vertigo. A small lesion in the middle cerebellar peduncle in the anterior inferior cerebellar artery territory and no lesion in the dentate nucleus in the posterior inferior cerebellar artery territory are thought to explain the minimal cerebellar signs despite the relatively large size of the infarction. Thus a relatively large infarction of the vertebral-basilar territory can manifest as sudden deafness with vertigo. Neuroimaging, including magnetic resonance imaging, is strongly recommended for patients with sudden deafness and vertigo to exclude infarction of the vertebral-basilar artery territory.

Acute Disease↗

PubMed2005

Spontaneous haemophilus influenzae type B meningoventriculitis with intraventricular debris.

Here we report the first case of spontaneous occurrence of Haemophilus influenzae type B meningoventriculitis. A 47-year-old man suffered from fever and headache. He had neck stiffness, and his cerebrospinal fluid (CSF) was turbid and yellowish. Gram staining and latex agglutination test of his CSF indicated that Haemophilus influenzae type B was the causative organism. Cranial CT and MRI revealed right ventricular debris accumulation, periventricular hyperintense signal, and periventricular ependymal enhancement. He was treated with intravenous administration of antibiotics, and his clinical condition and MRI findings gradually improved. Six weeks after onset, he was discharged without sequelae.

Anti-Bacterial Agents↗

PubMed2004

Mutations of the MTHFR gene (428C>T and [458G>T+459C>T]) markedly decrease MTHFR enzyme activity.

Methylenetetrahydrofolate reductase (MTHFR) is the only route for the synthesis of 5-methyltetrahydrofolate, which is utilized to convert homocysteine to methionine. In this study, we measured the enzyme activity of a mutant MTHFR that was detected in a patient with hyperhomocysteinemia. The 428C>T mutation in exon 2 of the MTHFR gene is a novel mutation, while the [458G>T+459C>T] mutation in exon 2 is a previously reported mutation. The activity of mutant enzymes containing the 428C>T, [458G>T+459C>T] and 677C>T mutations was 12.7+/-4.7%, 48.1+/-18.8%, and 43.6+/-14.4%, respectively, of that of the wild type enzyme. Our results suggest that these two variants each result in a severe MTHFR deficiency, which causes a developmental delay and cerebral vascular disease.

Adolescent↗

PubMed2004

Stroke recurrence within the first year following cerebral infarction--Tottori University Lacunar Infarction Prognosis Study (TULIPS).

OBJECTIVES: To identify determinants of recurrence after ischemic stroke in the Japanese population. MATERIALS AND METHODS: We enrolled 885 patients with acute ischemic stroke that had been admitted to our community hospitals. A total of 831 cases were followed for 1 year after the index stroke. Patients were assigned to one of the ischemic stroke subtype groups based on the NINDS Stroke Data Bank criteria. RESULTS: Rates of stroke recurrence were significantly different among stroke subtype groups: 14.4% in cardioembolic infarction, 7.3% in atherothrombotic infarction (ATI), 6.2% in lacunar infarction (LI) and 7.8% in infarction of uncertain cause. Previous history of stroke was the predictor of stroke recurrence for the groups of ATI and LI patients, and diabetes mellitus was the predictor of recurrence for the group of LI patients. CONCLUSION: The rate of recurrence and risk factors for stroke recurrence are different by stroke subtypes.

Aged↗

PubMed2003

The antiplatelet aggregation effects of aspirin suppositories.

To confirm that aspirin suppositories are an effective treatment for acute ischemic stroke, we examined the suppressive effects of 200-mg aspirin suppositories on platelet aggregation. Aspirin suppositories suppressed platelet aggregation induced by ADP or collagen, and the suppression continued for 24 h. There was no significant difference in suppression of platelet aggregation between aspirin administered by suppository and orally given aspirin. These results suggest that aspirin suppositories are a useful treatment for acute ischemic stroke.

Adenosine Diphosphate↗

PubMed2003

Brainstem infarction presenting with neurogenic stuttering.

We reported a sixty-year-old man who developed acquired stuttering after a brainstem infarction. Infarctions were detected in the midbrain and upper pons. Neurogenic stuttering of this patients indicated that the midbrain and upper pons could be lesion sites responsible for acquired stuttering. We speculated that the reticular network extending from the brainstem to the frontal cortices, and the periaqueductal gray matter could be closely related regions generating neurogenic stuttering.

Brain Stem Infarctions↗

PubMed2002

[A young adult case of spontaneous basilar artery dissection].

We reported a case of basilar artery dissection in a 20-year-old man suffering sudden onset of consciousness disturbance. Brain CT revealed a cerebral infarction of the whole territories of vertebro-basilar artery and his 3DCT showed the occlusion at the base of basilar artery. Autopsy revealed that the subintimal dissection was found at the base of basilar artery and the dissection was spreaded to the distal of bilateral posterior cerebral arteries. The characteristics of his vertebro-basilar artery were small in diameter, thin media and thickened intima. According to these findings, we supposed this rare case of basilar dissection occurred all at once based on a functional abnormality in his small vertebro-basilar arterial wall.

Adult↗