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Biomedical subjects

S Higashi

Publications and source records attributed to S Higashi.

At least 163 records · Page 9Linked to original sources
PubMed1990

Formation of crossed and uncrossed projections in the central nervous system.

Cellular mechanisms for decision of laterality of projections are discussed based on the observation of corticorubral and interpositorubral projections in the kitten. In both systems unilateral projections in adults appear to emerge from bilateral projections which occur early in development. Early unilateral lesions of the cerebral cortex or the interpositus nucleus cause persistent bilateral projections. Thus the neurons which eventually make a unilateral projection have the capability of forming synaptic connections with their target cells on both sides of the brain. Aberrant crossed (or uncrossed) projections in neonatal animals retract without forming complex axonal arbors, while those in lesioned animals form complex axonal arbors. Thus, success or failure in forming axonal arbors may be crucial for the maintenance of the aberrant crossed (or uncrossed) projections.

Animals↗
PubMed1990

Monoclonal antibody (VII-M31) to bovine factor VII: a specific epitope in the gamma-carboxyglutamic acid domain.

A murine monoclonal antibody (designated VII-M31) directed against bovine factor VII was prepared and characterized. Antibody VII-M31 inhibited the activations of both factors IX and X catalyzed by factor VIIa in the presence of tissue factor, phospholipids, and Ca2+. It possessed a strong affinity for factor VII in the presence of 5 mM Ca2+ (Kd = 1.12 x 10(-10)M). The immunoblotting test of other bovine proteins with the antibody, such as prothrombin, factor X, factor IX, protein C, protein S, and protein Z, in addition to human factor VII, revealed that it recognizes only a Ca2(+)-dependent epitope in bovine factor VII. Furthermore, this antibody VII-M31 covalently coupled with Affi-Gel allowed a simple and rapid purification of bovine factor VII. To localize the antigenic site in factor VII, various segments including a gamma-carboxyglutamic acid (Gla)-domainless protein, a Gla-domain peptide and the fragments isolated from the lysyl endopeptidase digest, were prepared. Among them, the isolated Gla-domain peptide and Gla-domainless factor VII were no longer recognized by antibody VII-M31, indicating that the sequence around the cleavage site by a-chymotrypsin is required for the interaction between the antibody and factor VII. In accordance with this result, the antibody bound specifically to a Gla-containing peptide corresponding to the NH2-terminal 23-50 residues of factor VII, which contains the chymotryptic cleavage site. These results suggest that the specific epitope of this antibody is localized in the carboxy-terminal 28 residues of the Gla-domain constituting the amino-terminal portion of bovine factor VII.

1-Carboxyglutamic Acid↗
PubMed1990

A trans-unsaturated fatty acid in a psychrophilic bacterium, Vibrio sp. strain ABE-1.

A high level of a trans-unsaturated fatty acid was found in the phospholipids of a psychrophilic bacterium, Vibrio sp. strain ABE-1. This fatty acid was identified as 9-trans-hexadecenoic acid (C16:19t) by gas-liquid chromatography and infrared absorption spectrometry. C16:1(9)t accounted for less than 1% of the total fatty acids in cells grown at 5 degrees C and reached 12% of the total at 20 degrees C. We suggest that the increase in the level of the trans-unsaturated fatty acid is related to the high growth rate of this bacterium at elevated temperatures. Possible biological roles of the trans-unsaturated fatty acid in the adaptation of the microorganism to the ambient temperature are discussed.

Chromatography, Gas↗
PubMed1990

Three-dimensional observations of the relation between the natural enamel surface and the outermost layer in human permanent tooth.

A coronal enamel surface of a human permanent tooth and the exposed outermost layer etched with phosphoric acid or EDTA were observed in the same field by means of scanning electron microscopy. Gross structural patterns of the enamel surface were either of a flattened type showing no perikymata patterns of of undulating and overlapping types with grooves and convex ridges. The undulating and overlapping patterns showed an alternating structure of rows of numerous shallow and deeper prism-end pits or that of these pit rows combined with a smooth band. The pit rows were usually located in the grooves with succeeding slopes in the middle of coronal enamel, but, towards a cusp, they often existed in the convex ridges. The striae of Retzius reached the grooves of perikymata from cervical to the middle of coronal enamel; however, the arrangement of the striae did not always follow perikymata patterns towards a cusp. The overlapping pattern in cervical enamel and the flattened type in cuspal and cervical enamel usually had uniform structures of shallow, indistinct, or no prism-end pits. The surface 'prismless' layers containing indistinct prism structures were observed under these uniform structures.

Acid Etching, Dental↗
PubMed1990

[A mitochondrial encephalomyopathy due to partial cytochrome c oxidase deficiency with giant evoked potentials--a case report].

A case of mitochondrial encephalomyopathy with a partial cytochrome c oxidase deficiency was reported with special reference to electrophysiological studies. A 56-year-old man was readmitted to Himeji Central Hospital due to mental deterioration and character change. At the age of 44 when he was attacked by his first epileptic seizure, he was admitted to Himeji Central Hospital, where EEG abnormalities and cerebral atrophy were found. Anticonvulsants helped to relieve his generalized convulsions but the EEG abnormalities persisted. At age 46, he had the second generalized seizure, so he quit his job as a crane operator. His family began to notice deterioration of his intellectual function and hyperaggressive behavior. His daily activities, intellectual performance and mental condition gradually deteriorated (WAIS FIQ less than 60). Other clinical and laboratory findings are as follows: bilateral impaired hearing, no optic nerve atrophy, no disturbance of extra ocular muscle movements, mild wasting and weakness of his extremities, normal coordination and sensation, no myoclonus or other involuntary movements, normal laboratory data of serum creatinine kinase, lactate dehydrogenase and aldolase, and increased amount of lactate and pyruvate in serum and cerebrospinal fluid (CSF), no abnormal amino acids in urine. A biopsy specimen of right biceps brachii muscle revealed numerous ragged-red fibers in frozen sections stained by the Gomori trichrome method. These fibers did not react to a cytochrome c oxidase staining. An ATPase staining demonstrated an atrophy of type-2 fibers. An electron micrograph showed many mitochondria in the sarcoplasm but few paracrystalline inclusions. A biochemical analysis of the muscle biopsy also revealed a significant decrease in the cytochrome c oxidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Diseases↗
PubMed1990

"Moustache" appearance in craniopharyngiomas: unique magnetic resonance imaging and computed tomographic findings of perifocal edema.

This report describes two cases of craniopharyngioma with perifocal edema. In both patients, computed tomography and magnetic resonance imaging (MRI) revealed that the tumors occupied the suprasellar cistern, invaginated the floor of the 3rd ventricle and were tightly adherent to the ventricular walls. The intraventricular portions of the tumors were cystic, containing protein-rich fluid as suggested by MRI and confirmed by operative findings. There was perifocal edema in the hypothalamus adjacent to the intraventricular tumor, the optic tracts, and the posterior limbs of the internal capsules, resembling the shape of a moustache on axial computed tomographic and MRI scans. The perifocal edema subsided after treatment of the intraventricular tumor by surgical resection or radiation therapy. The "moustache" appearance seems a unique, characteristic feature of perifocal edema, which is observed infrequently with certain craniopharyngiomas.

Adult↗
PubMed1990

[Estimation of the reticuloendothelial function by positron emission computed tomography (PET) study in chronic liver disease].

We have developed a new liver scanning agent (Ga-68 human serum albumin microspheres) in a convenient kit for use in positron emission computed tomography (PET). In this study, this scanning agent was evaluated for clinical usefulness as a function test for the reticuloendothelial system. A dose of 5 micrograms/kg (1-2 mCi) of Ga-68 microspheres was injected intravenously to 25 patients, 11 with chronic hepatitis and 14 with liver cirrhosis, and 5 normal volunteers for PET imaging of the liver and spleen using HEADTONE-III (SET 120W). The volumes of the liver and the spleen and the uptakes of Ga-68 microspheres were calculated as an index of the reticuloendothelial system function. In liver cirrhosis the liver volume estimated by PET was decreased and the spleen volume was increased. Both the liver uptake rate and differential absorption ratio (DAR) of the radioactivity were decreased corresponding with the degree of chronic liver disease. The spleen uptake rate was increased with progression of chronic liver diseases, but there was no difference in DAR between normal volunteers and patients with chronic liver disease. it was concluded that PET using Ga-68 microspheres is useful in the evaluation of the function of the reticuloendothelial system.

Chronic Disease↗
PubMed1990

[Brain perfusion SPECT imaging before and during the acetazolamide test using 99mTc-HMPAO].

A new method using brain perfusion 99mTc-HMPAO SPECT imaging was developed for evaluating cerebral perfusion reserve by the acetazolamide test with a short period. The first SPECT study was carried out for 13.5 min to obtain SPECT images at the resting state after 3 min postinjection of 555 MBq (15 mCi) of 99mTc-HMPAO. At the same time as the start of the first SPECT study, 1 g of acetazolamide was intravenously injected. Immediately after the stop of the 1st SPECT study, 925 MBq (25 mCi) of 99mTc-HMPAO from the same vial as in the first study was additionally injected. Three minutes later the second SPECT study was carried out for 10 min. After reconstruction the tomographic images in the first study were subtracted from the images in the second study to obtain those during the acetazolamide test after correction of the time differences in data acquisition between the two studies. This subtraction technique gives independent brain perfusion SPECT images before and during the acetazolamide test. Besides, the regional flow changes during the test were quantitatively analyzed. In conclusion this method seems to be practically useful for evaluating regional brain perfusion before and during drug treatments as a consecutive study with a short period of approximately 30 min.

Acetazolamide↗
PubMed1989

[The effects of angiographic contrast media on the aggregation and morphology of red cells in vitro].

The effects of four angiographic contrast media on the aggregation and morphology of human red cells in vitro, using microscopic observations were studied. The media included an ionic contrast medium, sodium meglumine amidotrizoate (amidotrizoate); non-ionic low-osmolal contrast media, iopamidol and iohexol; and an ionic low-osmolal contrast medium, sodium meglumine ioxaglate (ioxaglate). Strong, large aggregates formed in the control blood, without media, where aggregation of red cells was inhibited by contrast media mixed with the blood in a ratio of 2:1. Almost no aggregates were observed for amidotrizoate, an ionic contrast medium, while there were a few rouleaux formed in the presence of ioxaglate. Nearly all of the red cells aggregated in the presence of iopamidol and iohexol; iohexol produced the greater aggregation of the two. Besides rouleaux, irregular aggregates were formed with iohexol. When the contrast media were mixed with blood in a ratio of 1:2, their inhibitory effects on aggregation declined. These results clearly indicate that contrast media inhibit the in vitro aggregation of red cells, and ionic-contrast media produced more potent inhibitory effects than non-ionic media. With added NaCl and meglumine, iohexol did not induce red cell aggregation. This suggests that ionic-contrast media have greater inhibitory effects on aggregation than non-ionic media, a result of their ionic properties. Red cells were morphologically quite normal in the presence of ioxaglate, where most red cells were crenated in the presence of iopamidol and iohexol, and shrank in the presence of amidotrizoate. In the presence of iopamidol and iohexol with the osmolality adjusted to that of a saline solution, both normal red cells and crenation were observed. This suggests that non-ionic contrast media may directly effect morphological changes in red blood cells. These results revealed that ioxaglate, an ionic contrast medium, was the best in vitro medium, to prevent aggregation of red cells and crenation deformity of erythrocytes.

Contrast Media↗
PubMed1989

Multinucleated cells formed on calcified dentine from mouse bone marrow cells treated with 1 alpha,25-dihydroxyvitamin D3 have ruffled borders and resorb dentine.

Osteoclast-like multinucleated cells were formed from mouse bone marrow mononuclear cells, and their morphology on coverslips and on calcified dentine slices was compared by means of transmission electron microscopy. Addition of 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] to bone marrow cells cultured on coverslips greatly stimulated the formation of multinucleated cells within 8 days. These multinucleated cells had the cytological features of osteoclasts (abundant pleomorphic mitochondria, a large number of vacuoles and lysosomes, many stacks of Golgi membranes, and an extensive canalicular system), but they developed neither ruffled borders nor clear zones. The multinucleated cells appeared to result from direct fusion of mononuclear progenitor cells, whose structural features were similar to those of multinucleated cells. Like isolated osteoclasts, both multinucleated cells and their precursors exhibited an intense reaction for tartrate-resistant acid phosphatase (TRACP) in the cisterns of endoplasmic reticulum and lysosomes. Multinucleated cells formed from alveolar macrophages in the presence of 1 alpha,25(OH)2D3 were totally negative for TRACP reaction. When marrow cells were cultured on dentine slices in the presence of 1 alpha,25(OH)2D3, some of the multinucleated cells were located in the shallow resorption lacunae of dentine surfaces, and they developed the characteristic ruffled borders and clear zones. The narrow extracellular spaces of the ruffled borders, the adjacent pale endocytotic vacuoles, and the dark lysosomes located in the perinuclear cytoplasm of the multinucleated cells contained numerous apatite crystals delete in resorption lacunae. These results indicate that 1) the multinucleated cells formed on coverslips from mouse marrow cells treated with 1 alpha,25(OH)2D3 exhibit non-functional basic features of osteoclast morphology, and 2) differentiation of the multinucleated cells into functional osteoclasts requires some components of calcified dentine.

Acid Phosphatase↗
PubMed1989

Experimental intracranial hypertension following cisternal injection of various blood components.

Intracranial pressure (ICP) was recorded in 30 dogs which underwent cisternal injection of blood, serum, red blood cells (RBC). RBC ghosts, oxyhemoglobin or bilirubin. The amount of injection was 8-10 ml of blood or an equivalent volume of blood components. Blood or RBC showed a sustained ICP of 15 to 25 mmHg, and RBC ghosts caused a slight transient rise of ICP. In contrast, oxyhemoglobin or bilirubin induced marked intracranial hypertension up to 60-80 mmHg which was associated with frequent pressure waves. Histological examination disclosed aseptic meningitis at the base of the brain and inflammatory changes in the floor of the fourth ventricle after the injection of oxyhemoglobin or bilirubin. It is suggested that the breakdown products of RBC might be causative factors of the intracranial hypertension following subarachnoid hemorrhage.

Animals↗
PubMed1989

Luxury perfusion syndrome confirmed by sequential studies of regional cerebral blood flow and volume after extracranial to intracranial bypass surgery: case report.

We report a case of luxury perfusion syndrome with temporary neurological deterioration after extracranial to intracranial bypass surgery. A preoperative computed tomographic scan showed no detectable infarct, and the measurement of regional cerebral blood flow showed severe depression of ipsilateral hemispheric perfusion. The patient developed temporary neurological deterioration after bypass surgery, with no recognizable pathological signs on postoperative computed tomographic and angiographic studies. Regional cerebral blood flow and volume were more elevated during the period of neurological deterioration than after the subsequent recovery. This strongly suggests that excessive blood flow directed into chronically ischemic brain through a graft may induce a luxury perfusion syndrome resulting in neurological deterioration.

Brain Diseases↗
PubMed1989

Structure of the so-called 'prismless' enamel in human deciduous teeth.

The surface enamel of human deciduous teeth showing a more negative birefringence by polarized light was investigated by differential interference contrast microscopy and by scanning electron microscopy (SEM) following EDTA etching. Though this surface enamel has been generally called the 'prismless' enamel, in this study, the so-called 'prismless' enamel was categorized into 'false', 'moderate', 'essential' and 'complex' types according to whether they took the form of distinct prisms which bended at the subsurface, indistinct circularly based prisms or not. Based on the SEM observations some types of the 'prismless' enamel showed parallel crystallites and no prism boundaries. However, if indistinct prisms showing centripetal crystallites within the circular boundaries are admitted into the prismless enamel, other types except the 'false' one will generally belong to it.

Birefringence↗
PubMed1989

[A case of myelolipoma originating from bilateral adrenal glands; a comparison of CT and pathological findings].

We experienced a case of bilateral retroperitoneal tumor incidentally on CT which was carried out on suspicion of either cholelithiasis or choledocholithiasis. In company with other radiologic studies, US, angiography etc. we were able to make a correct diagnosis of adrenal myelolipoma preoperatively. Among these studies, CT coincided well with the structure of pathological findings and is thus the most powerful method for the diagnosis of myelolipoma. The case was discussed in addition to the studies of other literatures.

Adrenal Gland Neoplasms↗
PubMed1989

[Cerebral artery occlusion due to blunt cervical trauma].

Three cases are reported in which cerebral infarction developed due to blunt cervical trauma. All of these patients had external signs of cervical trauma and presented focal cerebral ischemic symptoms. Cerebral angiography demonstrated characteristic findings in each case. The first case: A 27 year-old man developed left hemiparesis four days after hitting his neck against a bed rail. Cerebral angiography showed complete occlusion of the right extracranial internal carotid artery 1.5 cm distal to its origin and emboli in distal branches of the right middle cerebral artery. He was treated conservatively. The second case: A 32 year-old man developed disturbance of consciousness with motor aphasia and right hemiparesis a few hours after hitting his chest and neck against baggage hanging from a crane. Cerebral angiography showed complete occlusion of the left middle cerebral artery and no abnormalities of the left internal carotid artery. He was treated with STA-MCA anastomosis two weeks after the accident. The third case: An 84 year-old man, who failed in a suicidal hanging, was semicomatose on admission and had right hemiparesis. Computed tomography demonstrated massive cerebral infarction of the territory of both anterior and left middle cerebral arteries. Cerebral angiography showed linear shadow defect of the left extracranial internal carotid artery corresponding with the site of the ligature. He was treated conservatively. From these angiographic findings, it was thought that intimal tear, intramural hematoma, vasospasm of the internal carotid artery and emboli given might bring about cerebral infarction. In such cases of blunt cervical trauma, cerebral angiography should be undertaken as soon as possible if focal cerebral ischemic symptoms can be seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Bacillus-shaped deposits composed of hexahedrally based crystals in human dental calculus.

In human supra- and subgingival calculus, bacillus-shaped deposits showing various rocky-pile forms composed of hexahedrally based crystals were observed by scanning electron microscopy. The crystal size measured approximately 0.1-1.5 microns. The electron probe microanalysis always detected calcium, phosphorous, and magnesium. Their molar ratios resembled those of magnesium-containing whitlockite and moreover the crystals also gave the electron diffraction pattern of whitlockite. The bacillus-shaped deposits happened to coexist with the intracellular calcifying microorganisms, furthermore, oral microorganisms partially replaced by the hexahedrally based crystals were found. The crystal deposits were never seen in the surface layers of calculus exposed to the oral cavity, but occurred in the innermost layers and intra-spaces of supragingival and ledge-type subgingival calculus and in the outer layers of deep subgingival calculus.

Bacillus↗