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Biomedical subjects

S Hatashita

Publications and source records attributed to S Hatashita.

At least 19 recordsLinked to original sources
PubMed2003

Regional distribution of potassium and phosphorus in ischemic brain tissue of rats with X-ray fluorescence analysis.

Focal cerebral ischemia was induced by occlusion of the left middle cerebral artery (MCAO) for 1 and 3 hours in 14 rats. Five sham-operated rats served as controls. Regional cerebral blood flow (rCBF) was assessed by 14C-iodoantipyrine radioluminography. The potassium and phosphorus contents in brain tissue were assessed using energy-dispersive X-ray fluorescence spectrometry. In the inner periphery within the ischemic tissue where rCBF was severely reduced to 6.61 +/- 0.95 ml/100 g/min 1 hour after MCAO, the potassium content decreased slightly to 12.82 +/- 0.15 mg/g. Potassium content decreased further to 10.61 +/- 0.24 mg/g over 3 hours after occlusion, similar to that in the ischemic core. In contrast, in the outer periphery where rCBF was moderately reduced, the potassium fell slightly to 12.78 +/- 0.46 mg/g 3 hours after MCAO. Tissue phosphorus content decreased to 8.28 +/- 0.24 mg/g only in the ischemic core. These findings demonstrate that potassium and phosphorus in brain tissue depend primarily on the extent, magnitude and duration of ischemia. Ion homeostasis of cell membranes may not be completely disturbed in the periphery around ischemic tissue for a short time after the onset of ischemia, even though blood flow is markedly reduced.

Animals↗
PubMed2001

Spinal extradural arachnoid cyst--case report.

A 48-year-old male presented with progressive leg weakness. Magnetic resonance imaging and computed tomography myelography showed an extradural arachnoid cyst extending from the T-12 to L-2 levels in the thoracolumbar region. The cyst was confirmed at surgery and completely removed. This surgical intervention achieved improvement in the neurological symptoms.

Arachnoid Cysts↗
PubMed2000

Determination of the spatial distribution of major elements in the rat brain with X-ray fluorescence analysis.

An energy dispersive X-ray fluorescence analysis was applied for determining the spatial (two-dimensional) distribution of elemental concentrations in rat brain sections. Freeze-dried brain sections prepared from normal and ischemic rats with middle cerebral artery occlusion were scanned with a collimated X-ray beam (0.18 mm in diameter, 50-kV acceleration voltage). The fluorescent Kalpha X-rays of P, S, Cl, and K were detectable, so that the two-dimensional distribution of fluorescent X-ray intensities could be determined for these elements. Furthermore, quantitative determination was possible for P and K by using the fundamental parameter technique. However, the accurate determination of Na and Ca was difficult, because of the low energy of Kalpha X-ray of Na, and the interference of K-Kbeta with Ca-Kalpha. The change in elemental concentrations in ischemic tissue, including the decrease in K concentration and increase in Cl concentration, was demonstrated by this method as a two-dimensional contour map. Since it is possible to obtain a pictorial representation of the elemental concentration in tissue sections, this method may be useful to evaluate the ionic changes in injured brain tissue in relation to histological or autoradiographical observations.

Animals↗
PubMed2000

Tentorial meningioma associated with pathological laughter--case report.

A 33-year-old male presented with involuntary and inappropriate laughter. Neuroimaging revealed a meningioma ventrolateral to the pons and midbrain, attached to the medial middle tentorium on the left side. The pathological laughter ceased immediately after subtotal removal of the tumor. Pathological laughter may be an early focal sign of a mass compressing ventrolateral brainstem.

Adult↗
PubMed1997

Blood volume and flow velocity through parenchymal microvessels in ischemic brain edema of rats.

Focal cerebral ischemia was produced in rats with left middle cerebral artery occlusion for 24 hours. Regional CBF was measured by the 14C-iodoantipyrine technique. The distribution of red blood cells (RBC) and plasma in cerebral microvessels was determined by radioluminography using 51Cr-RBC and 125I-bovine serum albumin, respectively. The mean transit times of RBC and plasma, blood volume, and hematocrit were calculated. The water content was measured by specific gravity. The blood flow was reduced to 2% of the control value in the central core, where the brain edema was the most severe. The blood volume decreased to 25% and the mean transit times of RBC and plasma increased about tenfold. In the outer periphery, where CBF was reduced to 39% but brain edema was not induced, the blood volume was decreased to 76% while the mean transit time of RBC was increased 2.1-fold, being greater than the increase in the plasma transit time. These findings indicate that focal ischemia has variable effects on the blood volume and flow velocities of RBC and plasma in the parenchymal microvessels depending on the depth of blood flow and edema. A decrease in blood flow is probably related to a reduction in the flow velocities of RBC and plasma in the surrounding ischemic tissue rather than to decreased number of perfused capillaries in the ischemic core.

Animals↗
PubMed1995

Arteriovenous malformation associated with a large cyst--case report.

A 37-year-old male presented with an arteriovenous malformation in the left temporal lobe associated with a large cyst. The cyst was drained and the nidus completely excised. The histological findings suggest that repeated subclinical hemorrhages from neovascular channels of the cyst membrane was responsible for the growth of the cyst.

Adult↗
PubMed1994

"Undifferentiated" cerebral primitive neuroectodermal tumor in a young adult--case report.

A 21-year-old female presented with a cerebral primitive neuroectodermal tumor (PNET) without either glial or neuronal differentiation, who has survived for 27 months without neurological deficit following total removal of the tumor, radiotherapy, and intensive chemotherapy. Both immunohistochemical and ultrastructural studies are important for the diagnosis of PNET. "Undifferentiated" PNET may be a distinct entity from common PNET which shows either glial or neuronal differentiation or both.

Adult↗
PubMed1994

Distribution of carbon-14 and associated radiation dose in rat fetal brain and liver after maternal injection of [14C]thymidine.

Pregnant Sprague-Dawley rats were injected intravenously with [14C]thymidine on day 13.5 of gestation, and the concentrations and radiation doses of 14C in the fetal brain and liver were determined by liquid scintillation counting and autoradiography with imaging plates. The concentrations of 14C in the whole fetal brains determined by liquid scintillation counting were 1.01% of the injected dose per gram wet weight at 6 h after injection and decreased to 0.39% g-1 at 48 h after injection. A significant accumulation of 14C was observed in the fetal liver: 3.8 and 0.51% of the injected dose per gram wet weight at 6 and 48 h after injection, respectively. Autoradiography showed that, especially at earlier periods after injection, there was remarkable concentration of 14C in the ventricular zone of the brain and the central region of the liver. With increasing time after injection, the distribution of 14C became relatively uniform. The concentrations of 14C in the ventricular zone of the fetal brain, determined by autoradiography, were much higher than those in the whole brain as determined by liquid scintillation counting. Cumulative radiation doses for 6-48 h after injection were 1.27 mGy for the whole fetus and 1.45 mGy for the whole brain. In contrast, the cumulative radiation dose for the ventricular zone of the brain which was determined by autoradiography was approximately 2.2 times that for the whole brain.

Animals↗
PubMed1993

Acute subdural hematoma: severity of injury, surgical intervention, and mortality.

Sixty patients with acute subdural hematoma were treated at Tokyo Metropolitan Hiroo Hospital between 1981 and 1989. The overall mortality was 55% and the functional recovery rate 30%. Thirteen (93%) of 14 patients with a Glasgow Coma Scale (GCS) score of 3 died, while all eight patients with a GCS score of 7 or more achieved functional recovery. The mortality of patients with GCS scores of 4-6 ranged from 45 to 67%. Patients with GCS scores of 4-6 over 65 years old had a mortality of 82%, compared to 50% mortality for those aged 19-40 years. The mortality for patients with GCS scores of 4-6 operated on within 4 hours of injury was 62% in contrast to 33% for those operated on from 4 to 10 hours. Patients with GCS scores of 4-6 who underwent craniotomy with evacuation of the hematoma achieved significantly better recovery than those treated by burr holes. Four patients with GCS scores of 4-6 died in spite of decompressive craniectomy or craniotomy with duroplasty. The mortality is only influenced by age and type of surgical intervention among patients with GCS scores of 4-6. Shorter time from injury to surgical evacuation does not affect mortality within 10 hours of injury.

Adolescent↗
PubMed1992

Malignant fibrous histiocytoma in the skull--case report.

A 45-year-old male presented with a large calvarial mass caused by a malignant fibrous histiocytoma arising primarily from the frontal bone and extending into the intracranial space. Magnetic resonance imaging revealed a well-demarcated, mottled enhanced bulky tumor with several low-signal separations. He underwent extensive tumor and bone removal, followed by radiation therapy. Histological examination showed pleomorphic spindle cells in a storiform pattern. The tissue stained positive for alpha-1-antitrypsin and alpha-1-antichymotrypsin by immunohistochemical techniques.

Frontal Bone↗
PubMed1991

Cystic cavernous angioma--case report.

A rare case of a cystic cavernous angioma in a 20-year-old female was diagnosed preoperatively by magnetic resonance imaging and computed tomography. Total surgical removal resulted in a successful recovery. Cystic cavernous angioma is benign and can be completely-removed. The importance of magnetic resonance imaging in the differential diagnosis is emphasized.

Adult↗
PubMed1990

Brain edema and cerebrovascular permeability during cerebral ischemia in rats.

Focal cerebral ischemia was produced by occluding the left middle cerebral artery in 769 rats. Permeability of the blood-brain barrier to small or large molecules was evaluated qualitatively using Evans blue or sodium fluorescein and quantitatively using the transfer indexes of iodine-125-labeled bovine serum albumin or [14C]sucrose. Water content was determined using wet and dry weights and sodium and potassium contents using flame photometry. Cortical tissue in the middle cerebral artery territory was sampled less than or equal to 14 days after occlusion. A significant increase in the albumin transfer index was first found 12 hours after occlusion, and the index remained approximately the same until water content peaked 3 days after occlusion. In contrast, the sucrose transfer index increased gradually, significantly correlated with increases in the water and sodium contents. Tissue staining by sodium fluorescein was more extensive than that by Evans blue. As edema fluid decreased gradually 4-10 days after occlusion, the albumin and sucrose transfer indexes increased markedly. These findings indicate that disruption of the blood-brain barrier to small molecules is accompanied by accumulation of edema fluid during the later stages of ischemia. Opening of the barrier to serum protein is probably related to the resolution of edema.

Animals↗
PubMed1990

Tuberculoma of the cerebellum--case report.

A 25-year-old female presented with a 1-month history of headache and vomiting. Computed tomography revealed several enhanced nodules with surrounding edema in the right cerebellum. A T2-weighted magnetic resonance image showed heterogeneous high signal intensity throughout the right cerebellar hemisphere. A tuberculin skin test was positive and the erythrocyte sedimentation rate was slightly high, but there was no other clinical evidence of a tuberculous process. The histological diagnosis of the surgical specimen was tuberculoma. The combination of surgery and antituberculosis chemotherapy eradicated the cerebellar lesions.

Adult↗
PubMed1990

Role of blood-brain barrier permeability in focal ischemic brain edema.

We studied how changes in BBB function are related to the development of ischemic brain edema. Focal cerebral ischemia was produced by left MCA occlusion in rats. The permeability of the BB to small or large molecules was evaluated qualitatively by the extravasation of EB or NaFl dyes and quantitatively by the uptake index of 125I-BSA or 14C-sucrose. Brain water content was determined by specific gravity. Measurements were made from the cortical core of the MCA territory within 14 days of occlusion. Water content progressively increased within 2 days of occlusion and then gradually decreased up to 14 days. Lightly stained EB areas were located only in the proximal portion of the ischemic core. The incidence of NaFl extravasation was similar to that of EB within 2 days of occlusion but was greater than that of EB 3 days after occlusion. NaFl staining diffusely extended into the ischemic core. Although the index of 125I-BSA increased only slightly within 2 days of occlusion, a marked increase in 125I-BSA was found after 3 days. The index of 14C-sucrose increased gradually after occlusion, reaching a peak at 8 days. These findings indicate that the change in BBB permeability is minimal in ischemic brain tissue when the accumulation of edema fluid is maximal and suggest that BBB alteration in ischemic brain tissue may be associated with the stabilization or resolution of the ischemic lesion.

Animals↗
PubMed1990

An osmotic gradient in ischemic brain edema.

We studied how the osmotic pressure gradient between blood and the brain is related to the development of ischemic brain edema. Focal cerebral ischemia was produced by left MCA occlusion in rats. Brain osmolality was determined with a vapor pressure osmometer, water content of the brain tissue was measured by wet and dry weight, and the tissue sodium and potassium contents were assayed by flame photometry. Permeability of BBB was tested by EB. These measurements were made from the cortical core of MCA territory at various intervals from 1 hr to 14 days after occlusion. Brain osmolality increased from 311 +/- 2 mOsm/kg (M +/- SE) to 329 +/- 2 mOsm/kg (n = 7, p less than 0.01) by 6 hrs after occlusion. Serum osmolality did not significantly change. The osmotic gradient between blood and the brain was about 26 mOsm/kg. Brain osmolality then decreased to 310 +/- 2 mOsm/kg by 12 hr after occlusion and remained about the same level for up to 14 days. Water content progressively increased within 1 day, then gradually decreased by 14 days. Sodium plus potassium content of the brain tissue did not increase and EB extravasation was not seen within 6 hr of occlusion. These findings indicate that an osmotic pressure gradient contributes to the formation of edema only during the early stage of cerebral ischemia. Brain osmolality is not related to tissue electrolyte change and BBB disruption to protein.

Animals↗
PubMed1988

Ischemic brain edema and the osmotic gradient between blood and brain.

The relationship of the osmotic pressure gradient between blood and brain, and the development of ischemic brain edema was studied. Focal cerebral ischemia was produced by left middle cerebral artery occlusion in rats. Brain osmolality was determined with a vapor pressure osmometer, brain water content by wet-dry weight, and tissue sodium and potassium contents by flame photometry. Permeability of the BBB was tested by Evans blue. Measurements were made from the ischemic cortex within 14 days of occlusion. Brain osmolality increased from 311 +/- 2 to 329 +/- 2 mOsm/kg by 6 h after occlusion. Serum osmolality did not change significantly. The osmotic gradient between blood and brain peaked at approximately 26 mOsm/kg. Brain osmolality then decreased to 310 +/- 2 mOsm/kg by 12 h after occlusion and remained at about that same level. Water content increased progressively within 1 day of occlusion, then gradually decreased by 14 days. Brain tissue sodium plus potassium content did not increase within 6 h of occlusion, and Evans blue extravasation was not seen within that time. These findings indicate that an osmotic pressure gradient contributes to the formation of edema only during the early stage of cerebral ischemia. Furthermore, the increase in brain osmolality is not related to tissue electrolyte change or BBB disruption to protein.

Animals↗
PubMed1988

Biomechanics of brain edema in acute cerebral ischemia in cats.

We studied whether the biomechanical properties of brain play an important role in the development of early ischemic brain edema in cats with middle cerebral artery occlusion. Brain tissue pressure, tissue compliance, and tissue resistance were measured from the gray matter in the core and the periphery of the middle cerebral artery territory for 6 hours after occlusion. Regional cerebral blood flow and water content were also measured from the same areas. Ventricular fluid pressure was recorded. Tissue pressure rose gradually in the core, where flow was 6 ml/100 g/min, over 4 hours and then stabilized. The pressure gradient measured between edematous tissue and ventricular fluid was 5.3 mm Hg. Tissue resistance increased 1 hour after occlusion when water content increased to 10 mg/g. Later, when water content increased by 40 mg/g, tissue resistance decreased and tissue compliance increased significantly. In the periphery, where flow was 17.6 ml/100 g/min, tissue pressure rose slightly while tissue compliance and tissue resistance did not change within 6 hours. Our data indicate that as ischemic injury progresses, edema fluid accumulates in highly compliant brain parenchyma, then migrates through highly conductive tissue into the cerebrospinal fluid spaces, driven by the hydrostatic pressure gradient between the edematous tissue and the cerebrospinal fluid.

Acute Disease↗