Publications by authors named "Ken Kazama"

Article Synopsis
  • A 31-year-old woman experienced a sudden headache and altered consciousness, leading to the discovery of a left acute subdural hematoma and a small aneurysm on her left distal posterior cerebral artery, which was treated with coil embolization.
  • Two weeks later, she developed complete left hemiplegia due to an occluded right middle cerebral artery, requiring a mechanical thrombectomy that successfully restored blood flow.
  • Ultimately, she was diagnosed with infective endocarditis after positive blood cultures revealed bacterial presence and a TEE identified vegetation on the mitral valve; she was treated with penicillin and discharged without neurological deficits.
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The semi-sitting position is well known to neurosurgeons. However, there are few reports of microvascular decompression surgery for glossopharyngeal neuralgia performed using the semi-sitting position. The semi-sitting position is not widely adopted in Japan, but it is considered to be a very useful neurosurgical position.

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Objective: Hypoperfusion during carotid artery cross-clamping (CC) for carotid endarterectomy (CEA) may result in the major complication of perioperative stroke. Median nerve somatosensory evoked potential (MNSSEP) monitoring, which is an established method for the prediction of cerebral ischemia, has low sensitivity in detecting such hypoperfusion. In this study the authors sought to explore the limitations of MNSSEP monitoring compared to tibial nerve somatosensory evoked potential (TNSSEP) monitoring for the detection of CC-related hypoperfusion.

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A 56-year-old man underwent cervical laminoplasty for cervical spondylosis. On the 7th postoperative day, he suddenly felt severe neck pain, and tetraplegia developed rapidly over 1.5 hrs.

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Intratumoral bleeding from a meningioma is very rare. We herein report a case of a foramen magnum meningioma which presented in association with intratumoral bleeding. A 49-year-old female who had been suffering from occipital headache and shoulder pain on neck motion was referred to our hospital to undergo treatment for a tumor located in the posterior fossa.

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Angiotensin II (Ang II) exerts detrimental effects on cerebral circulation, the mechanisms of which have not been elucidated. In particular, Ang II impairs the increase in cerebral blood flow (CBF) produced by neural activity, a critical mechanism that matches substrate delivery with energy demands in brain. We investigated whether Ang II exerts its deleterious actions by activating Ang II type 1 (AT1) receptors on cerebral blood vessels and producing reactive oxygen species (ROS) through NADPH oxidase.

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We investigated the role of vascular oxidative stress in the mechanisms of the impairment in cerebrovascular regulation produced by the amyloid-beta peptide (Abeta). In particular, we sought to provide evidence of vascular oxidative stress in mice overexpressing the amyloid precursor protein (APP) and to determine whether the Abeta-induced attenuation in functional hyperemia is mediated by free radical overproduction. Oxidative/nitrosative stress was assessed by 3-nitrotyrosine immunoreactivity, while free radical production was determined in cerebral microvessels by hydroethidine microfluorography.

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We investigated whether angiotensin II (ANG II), a peptide that plays a central role in the genesis of hypertension, alters the coupling between synaptic activity and cerebral blood flow (CBF), a critical homeostatic mechanism that assures adequate cerebral perfusion to active brain regions. The somatosensory cortex was activated by stroking the facial whiskers in anesthetized C57BL/6J mice while local CBF was recorded by laser-Doppler flowmetry. Intravenous ANG II infusion (0.

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The amyloid-beta (A beta) peptide, which is derived from the amyloid precursor protein (APP), is involved in the pathogenesis of Alzheimer's dementia and impairs endothelium-dependent vasodilation in cerebral vessels. We investigated whether cerebrovascular autoregulation, i.e.

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We have used quantitative autoradiographic techniques to study the relationship between cerebral blood flow (CBF) and glucose utilization (CGU) in two lines of transgenic mice overexpressing Swedish mutant amyloid precursor protein (APP) and APP-derived Abeta peptides. Mice were studied at an age when there are no amyloid plaques. In the 2123 line, CBF was reduced only in telencephalic regions with no corresponding decrease in CGU.

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