Publications by authors named "Hiroshi Nawashiro"

Article Synopsis
  • Blast-induced traumatic brain injury (bTBI) can result from direct exposure to blast waves on the head as well as from shock waves affecting the torso, but the real-time effects of torso exposure on the brain remain poorly understood.
  • In this study, rat groups were exposed to laser-induced shock waves targeting the brain, lungs, or both, allowing researchers to isolate the impact of shock waves on brain health without other external factors.
  • Results showed that exposure to shock waves on the brain led to significant brain injury, but interestingly, even lung exposure alone resulted in serious brain issues; combined exposure caused the most severe effects, indicating distinct mechanisms behind motor dysfunction depending on the exposure location.
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Although an enormous number of animal studies on blast-induced traumatic brain injury (bTBI) have been conducted, there still remain many uncertain issues in its neuropathology and mechanisms. This is partially due to the complex and hence difficult experimental environment settings, e.g.

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Article Synopsis
  • Blast-induced traumatic brain injury is a growing issue in neurotraumatology, but understanding its mechanisms is limited due to a lack of data on brain responses during shock wave exposure.
  • Researchers used a laser-induced shock wave on rats to study changes in the brain's vasculature and oxygen levels through multispectral imaging.
  • Findings showed that after exposure, blood flow and oxygen levels dropped, followed by a brief period of increased blood flow but a sustained state of low oxygen, indicating a potential link between these conditions and brain damage from shock waves.*
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  • * Imaging revealed an intracranial mass affecting the superior sagittal sinus, but no bone changes were noted, and no direct connection was found between the intracranial and subcutaneous lesions during surgery.
  • * Both masses were confirmed as the same atypical meningioma (World Health Organization grade II) upon histopathologic examination, with a potential pathway for the tumor's extension suggested through the parietal foramen.
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In ischemic stroke research, a better understanding of the pathophysiology and development of neuroprotection methods are crucial, for which in vivo imaging to monitor spreading depolarizations (SDs) and evolution of tissue damage is desired. Since these events are accompanied by cellular morphological changes, light-scattering signals, which are sensitive to cellular and subcellular morphology, can be used for monitoring them. In this study, we performed transcranial imaging of near-infrared (NIR) diffuse reflectance at ∼800 nm, which sensitively reflects light-scattering change, and examined how NIR reflectance is correlated with simultaneously measured cerebral blood flow (CBF) for a rat middle cerebral artery occlusion (MCAO) model.

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Background: Enhanced oxidative stress occurs in spontaneously hypertensive stroke-prone rats (SHRSP), and is important in blood-brain barrier (BBB) disruption. Hydrogen can exert potent protective cellular effects via reduction in oxidative stress in various diseases. The present study investigated whether long-term hydrogen treatment can improve neurological function outcome in the SHRSP model, and the effects of hydrogen on BBB function, especially the oxidative stress and the activity of matrix metalloproteinases (MMPs) in this model.

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Chronic subdural hematomas (SDHs) associated with non-operated moyamoya disease are extremely rare. A 68-year-old woman underwent burr-hole surgery for a right SDH, which resolved completely. On day 3, however, the patient suffered cerebral infarction in the right parietal lobe.

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Objective: We report the technique of three-dimensional computed tomography angiography (3D CTA)+two-dimensional computed tomographic (2D CT) imaging as an adjunct in early surgery for a ruptured anterior communicating artery (ACoA) aneurysm by adopting an anterior interhemispheric approach. These combined imaging modalities provide accurate intraoperative anatomical information.

Methods: To produce images for an anterior interhemispheric approach, 3D CTA+2D coronal CT images, which are perpendicular to the direction of the surgical approach at three levels (brain surface, genu of the corpus callosum and aneurysm neck), were constructed.

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Hypertrophic pachymeningitis is an uncommon disorder that causes a localized or diffuse thickening of the dura mater. Recently, the possibility that IgG4-related sclerosing disease may underlie some cases of intracranial hypertrophic pachymeningitis has been suggested. We herein report the tenth case of IgG4-related intracranial hypertrophic pachymeningitis and review the previous literature.

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Photomechanical waves (PMWs), which were generated by irradiation of a light-absorbing material (laser target) with nanosecond laser pulses, were used for targeted transvascular drug delivery in rats. An Evans blue (EB) solution was injected into the tail vein, and laser targets were placed on the skin, muscle and brain. Each laser target was irradiated with a laser pulse(s) and 4h later, the rat was perfused and the distribution of EB fluorescence in the targeted tissues was examined.

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Background: A recent phase 1/2 clinical trial argued for caution for the use of sulfasalazine in progressive glioblastoma (GBM). However, the study enrolled patients with recurrent or progressive high-grade glioma indicating that patients recruited probably had severe disease. Thus, the study may not accurately reflect the effectiveness of sulfasalazine for GBM and we hypothesized that earlier sulfasalazine administration may lead to anticancer effects.

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Epidural hematoma (EDH) in newborn infants is rare compared with other types of intracranial hemorrhages. Furthermore, posterior fossa EDH is extremely rare. We present a case of posterior fossa EDH in an infant with Menkes disease with accessory bones in the occiput.

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Localized neurofibromas are rare in the orbit and, unlike the more common plexiform neurofibromas, are not typically associated with von Recklinghausen neurofibromatosis. We present a rare case of localized neurofibromas in the bilateral orbits.

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Despite many efforts, the pathophysiology and mechanism of blast-induced traumatic brain injury (bTBI) have not yet been elucidated, partially due to the difficulty of real-time diagnosis and extremely complex factors determining the outcome. In this study, we topically applied a laser-induced shock wave (LISW) to the rat brain through the skull, for which real-time measurements of optical diffuse reflectance and electroencephalogram (EEG) were performed. Even under conditions showing no clear changes in systemic physiological parameters, the brain showed a drastic light scattering change accompanied by EEG suppression, which indicated the occurrence of spreading depression, long-lasting hypoxemia and signal change indicating mitochondrial energy impairment.

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The effects of laser polarization on the efficacy of near-infrared low-level laser therapy for spinal cord injury (SCI) are presented. Rat spinal cords were injured with a weight-drop device, and the lesion sites were directly irradiated with a linearly polarized 808-nm diode laser positioned either perpendicular or parallel to the spine immediately after the injury and daily for five consecutive days. Functional recovery was assessed daily by an open-field test.

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Numerous studies on hydrocephalus after decompressive craniectomy (DC) for severe traumatic brain injury have been reported, whereas there have been only two reports on DC for hemispheric cerebral infarction. Here, we present the clinical details of 23 patients who underwent DC for hemispheric cerebral infarction and the incidence of hydrocephalus following DC. Of the 23 patients, 13 were male and 10 were female, with an age range from 34 to 75 years (mean, 60.

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Decompressive craniectomy (DC) improves the survivability and functional outcome in patients with malignant hemispheric infarction (MHI). The decompressive effect of DC depends on the decompressive volume (DV). The value of the formulas for estimating DV has not been reported to date.

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Objective: Decompressive craniectomy (DC) is an established therapeutic option following severe traumatic brain injury (TBI). However, several delayed complications of DC have been reported, including ventriculomegaly, which can lead to poor patient outcomes. Nevertheless, ventriculomegaly can occur after TBI even without DC.

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Hemispheric hypertensive intracerebral hemorrhage (ICH) has a high mortality rate. Decompressive craniectomy (DC) has generally been used for the treatment of severe traumatic brain injury, aneurysmal subarachnoid hemorrhage, and hemispheric cerebral infarction. However, the effect of DC on hemispheric hypertensive ICH is not well understood.

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