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Biomedical subjects

H Nawashiro

Publications and source records attributed to H Nawashiro.

At least 37 records · Page 2Linked to original sources
PubMed2001

Anomalous internal carotid artery associated with ipsilateral cerebral arteriovenous malformation--case report.

A 15-year-old girl presented with an extremely rare anomalous origin of the internal carotid artery (ICA) from the common carotid artery, associated with an arteriovenous malformation in the brain and aberrant course of the ICA in the temporal bone. These anomalies, which were found on the same side, may be due to a maldevelopment of the vascular network including the aortic arches.

Adolescent↗
PubMed2001

Peduncular hallucinosis due to a pineal meningioma. Case report.

The authors report the case of a 53-year-old woman who experienced visual hallucinations diagnosed as peduncular hallucinosis (PH). The cause of the PH was compression of the quadrigeminal plate and/or the splenium due to a meningioma originating from the falcotentorial junction (pineal meningioma). The nature of the visual hallucinations was depicted in drawings created by the patient herself. This is the first report of PH caused by a tumor located in the pineal region.

Female↗
PubMed2001

[Tiny aneurysms of cortical arteries presenting as an acute subdural hematoma: a case report].

A case of an acute subdural hematoma due to the rupture of a tiny aneurysm of a cortical artery is described. A 68-year-old man lightly hit the right side of his head. About 1 hour later, he became drowsy and exhibited moderate hemiparesis on the left side on admission. Computed tomographic scanning demonstrated an acute subdural hematoma on the right temporoparietal region. In the past, he had undergone the clipping of a non-ruptured aneurysm and a subdural-peritoneal shunt operation on the same side in another hospital. On surgical evacuation of the subdural hematoma, a pulsating bleeding from a ruptured tiny aneurysm of a cortical artery was observed. There were also some similar tiny aneurysms on other cortical arteries. A photograph of such a tiny aneurysm was first taken and presented.

Aged↗
PubMed2001

[Influence of intubation maneuver with or without premedication for intracranial hemorrhage with unconsciousness].

PURPOSE: To clarify the influence of intubation maneuver with or without premedication for intracranial hemorrhage with unconsciousness. METHODS: Between May 1995 and May 2000, we analyzed retrospectively 46 patients who had received intubation for unconsciousness and were found non-traumatic intracranial hemorrhage by head computer tomography at the Trauma and Critical Care Center, National Defense Medical College. They were divided into two groups, Drug group in which drugs were used before intubation and Control group which were intubated without drugs. Physical findings on admission, head CT findings, Glasgow Outcome Score(GOS) at discharge were analyzed between the groups. RESULTS: There were no significant differences for background of subjects between the groups. In the Drug group, diazepam, pentazocine, lidocaine, nifedipine and nicardipine were used before intubation. GOS in the Control group was significantly greater than in the Drug group(p < 0.01). CONCLUSION: In case of intubation for unconscious patients who may suffer intracranial hemorrhage, using premedication leads to favorable outcome.

Adult↗
PubMed2000

Real time monitoring of glutamate following fluid percussion brain injury with hypoxia in the rat.

In this study, extracellular glutamate (Glu) was monitored in real time using a biosensor following traumatic brain injury (TBI) either with or without inducing hypoxia in the rat Fluid-percussion model. We also measured the cortical contusion volume at 3 days after the insult. The animals were divided into 3 groups. Group 1 was subjected to TBI only, Group 2 to TBI followed by 20 min of moderate hypoxia (FiO2: 10%) and Group 3 to 20 min of moderate hypoxia without TBI. The surge increase in the extracellular Glu concentration occurred immediately after TBI in Groups 1 and 2. Group 2 showed a prolonged efflux of Glu during hypoxia. Group 3 Glu showed low continuous steady levels. The contusion volume in Group 2 was significantly larger than in Group 1. To test the possible involvement of apoptosis in Groups 1 and 2, rats were sacrificed at 1, 6, 24 and 72 h after TBI. Immunohistochemical studies showed an increased number of both CPP32 positive cells at 24 h and TUNEL cells at 72 h in Group 2. These results suggest that TBI with moderate hypoxia induced a prolonged efflux of Glu that resulted more cortical damage due to necrosis and apoptosis.

Animals↗
PubMed2000

The synergistic effect of high K+ and hypoxia on extracellular concentrations of neuroactive amino acid in hippocampus.

In the present study, we examined extracellular concentrations of glutamate (Glu) in hypoxia using ringer solution with a high potassium (K+) level using microdialysis. Based on our findings, we hypothesized that the concentration of extracellular K+ caused a greater efflux of Glu. We used male SD rats and separated them into 3 groups based on the K+ concentration of Ringer solution (RS), consisting of normal (4 mM), 40 mM and 150 mM groups. We stereotactically inserted the microdialysis probe into the hippocampus, and perfused the RS for 60 min before imposing hypoxia. Subsequently, while perfusing RS, hypoxia (7% O2 + 93% N2 gas) was induced in all 3 groups for 20 min. In the normal and 40 mM of K+ concentration groups, the Glu level did not increase, but in the 150 mM of K+ concentration group, the Glu level increased while being perfused with RS and a larger increase in Glu was observed after inducing hypoxia. This result suggests that the extracellular concentration of K+ plays a role in the mechanism of increased neuronal vulnerability caused by hypoxia after TBI.

Animals↗
PubMed2000

Mn-SOD and Bcl-2 expression after repeated hyperbaric oxygenation.

To clarify the mechanism of ischemic tolerance induced by HBO, we investigated the effect of HBO on immunoreactivity to Bcl-2 and Bax, apoptosis-regulating protein, or Mn-SOD, a radical scavenging system, in the CA1 sector of the gerbil hippocampus. Pretreatment comprising, five sessions at 2 ATA (atmosphere absolute) every other day, but not that comprising, ten sessions at 3 ATA every day, caused significant increases in Bcl-2 and Mn-SOD immunoreactivity in the CA1 sector compared with in the sham pretreatment group. No significant differences in Bax immunoreactivity and neuronal density in the CA1 hippocampal neurons was observed between the groups. These results suggest that protection against mitochondrial alterations after ischemia through Mn-SOD and/or Bcl-2 expression is related to the ischemic tolerance induced by repeated HBO pre-treatment.

Animals↗
PubMed2000

Early experiences of haemostasis on brain tumour surgery with Argon Plasma Coagulation (APC).

OBJECTIVE: We first applied a novel haemostatic strategy involving Argon Plasma Coagulation (APC), an innovative no-touch electrocoagulation technique in which a high-frequency alternating current is delivered to the tissue through ionized argon gas, to brain tumour surgery, and report its usefulness and limitations. METHODS: The APC system we used comprised an APC 300 developed by ERBE Elektromedizin GmbH, Germany. We applied APC to 13 brain tumours in 12 patients (5 meningiomas, 4 sarcomas, 2 glioblastomas, and 2 pituitary adenomas). To avoid unnecessary thermal injury to the tissue as much as possible, power/gas flow settings of 20 and 40 W were used. The impact time was varied individually but was around several seconds per one impact. The argon jet (1.5-4.5 L/min) clears a field of pooled blood and evenly conducts electrical energy to the target tissue. A thin and flexible probe particularly increased the usefulness of APC for haemostasis on deep-seated skull base tumour operations under a microscope. CONCLUSION: All patients were successfully treated and satisfied with the surgical results without any complications due to APC. APC appears to be an excellent alternative strategy for achieving haemostasis on vascular-rich brain tumour surgery, and may be valuable for the management of patients with coagulation defects.

Adenoma↗
PubMed2000

Cystic schwannoma of the orbit: case report.

BACKGROUND: Cystic lesions of the orbit have diverse clinical findings and histopathological features. We report an orbital schwannoma composed of a single cyst. CASE DESCRIPTION: A 62-year-old woman with an intraconal cystic tumor in the left orbital cavity is described. The cystic tumor was totally removed and the pathological diagnosis of the cyst wall was schwannoma composed of both Antoni type A and B. CONCLUSIONS: A rare case of cystic schwannoma of the orbit is reported. This case may contribute to an improved preoperative differential diagnosis for cystic lesions of the orbit.

Cysts↗
PubMed2000

Real-time monitoring of glutamate following fluid percussion brain injury with hypoxia in the rat.

In the present study, extracellular glutamate (Glu) was monitored in real time using an enzyme electrode biosensor following traumatic brain injury (TBI) either with or without inducing hypoxia in the rat. We also measured the cortical contusion volume at 3 days after insult by staining with 2,3,5-triphenyltetrazolium chloride (TTC). Male Sprague-Dawley rats (300-400 g) were anesthetized and then subjected to lateral fluid percussion (FP) brain injury of moderate severity (3.5-4.0 atm), using the Dragonfly device model (no. HPD-1700). The experimental animals were divided into four groups. Group 1 (n = 10) was subjected to TBI only, group 2 (n = 10) to TBI followed by 20 min of moderate hypoxia (FiO2: 10%), group 3 (n = 4) to 20 min of moderate hypoxia without TBI, and group 4 (n = 4) to sham. Seventy-two hours after the insults, the animals were sacrificed, their brains were stained with TTC, and the lesion volumes were calculated. A surge in the extracellular Glu concentration occurred immediately after TBI in groups 1 and 2. There was no significant difference between the two groups. Group 2 showed a prolonged efflux of Glu during hypoxia ( < 0.05). In group 3, Glu continued to show a mild increase. The cortical contusion volume in group 2 was significantly larger than that in group 1. To evaluate the possible involvement of apoptosis in groups 1 and 2, separate rats were sacrificed under the same procedures after 1, 6, 24, and 72 h after insult (n = 2/group). Immunohistochemical analysis demonstrated an increased number of both the cysteine protease caspase-3-positive cells at 24 h and TUNEL-positive cells at 72 h in group 2. These results suggest that TBI with moderate hypoxia induced the prolonged efflux of Glu, which thus resulted in more cortical damage due to necrosis and apoptosis.

Animals↗
PubMed2000

High susceptibility to cerebral ischemia in GFAP-null mice.

Astrocytes perform a variety of functions in the adult central nervous system (CNS) that contribute to the survival of neurons. Thus, it is likely that the activities of astrocytes affect the extent of brain damage after ischemic stroke. The authors tested this hypothesis by using a mouse ischemia model to compare the infarct volume produced in wild-type mice with that produced in mice lacking glial fibrillary acidic protein (GFAP), an astrocyte specific intermediate filament component. Astrocytes lacking GFAP have been shown to have defects in process formation, induction of the blood-brain barrier. and volume regulation; therefore, they might be compromised in their ability to protect the CNS after injury. The authors reported here that 48 hours after combined permanent middle cerebral artery occlusion (MCAO) and 15 minutes transient carotid artery occlusion (CAO) GFAP-null mice had a significantly (P < 0.001) larger cortical infarct volume (16.7 +/- 2.2 mm3) than their wild-type littermates (10.1 +/- 3.9 mm3). Laser-Doppler flowmetry revealed that the GFAP-null mice had a more extensive and profound decrease in cortical cerebral blood flow within 2 minutes after MCAO with CAO. These results indicated a high susceptibility to cerebral ischemia in GFAP-null mice and suggested an important role for astrocytes and GFAP in the progress of ischemic brain damage after focal cerebral ischemia with partial reperfusion.

Animals↗
PubMed2000

A quantitative analysis of head injury using T2*-weighted gradient-echo imaging.

BACKGROUND: T2*-weighted gradient-echo imaging (T2*-GE) is useful for detecting small hemorrhages. METHODS: Thirty-four patients were prospectively examined, first by magnetic resonance imaging (1.5 T) and then by T2-weighted fast spin echo (T2-FSE) and T2*-GE. Thereafter, the correlations between the T2-FSE or T2*-GE findings and the clinical or computed tomography findings were analyzed. RESULTS: The number of lesions detected by T2*-GE was 14.5 +/- 16.3 (mean +/- SD, n = 34), which was significantly (p < 0.001) greater than that detected by T2-FSE (5.6 +/- 5.6, n = 34). The findings of T2*-GE correlated positively with both the duration of unconsciousness (R2 = 0.74,p < 0.0001) and with Glasgow Outcome Scale (R2 = 0.81, p < 0.0001), whereas those of T2-FSE did not show any significant correlation. T2*-GE imaging could also detect all areas responsible for focal neurologic signs 1 month after in. jury, whereas T2-FSE imaging detected only 22 of 33 such signs. CONCLUSION: T2*-GE was found to be useful for evaluating the clinical symptoms of head injury.

Adolescent↗