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Biomedical subjects

S Higashi

Publications and source records attributed to S Higashi.

At least 181 records · Page 10Linked to original sources
PubMed1989

[Removal of hypertensive intracerebral hematoma with stereotactic aqua-stream and aspirator (SAS & A)].

The stereotactic aqua-stream and aspirator (SAS & A) was a modification of the aqua-stream and aspirator (AS & A) in order to remove hypertensive intracerebral hematoma. The newly designed needles were held with an adaptor to any kind of Leksell's, Patil's, UT's, Sugita's, or Komai's stereotactic equipment. The needles were stereotactically inserted into the center of the hematoma cavity through a burr-hole. The needles were composed of an outer tube and two inner tubes. The inner tubes were arranged parallel with each other. One was an irrigation tube of 0.1 mm in inner diameter, the other was a suction tube of 2 mm in outer diameter. The blood clot was sucked through a window of the outer tube by the aspirator and incarcerated there soon after. The incarcerated blood clot was crushed by a small streak of saline solution from the nozzle of the irrigation tube. Crushed clot and fluid were sucked through the suction tube. The extent of evacuation of the hematoma was evaluated by CT scans during stereotactic surgery. In all 10 cases of hypertensive intracerebral hematoma, 73-98% of hematoma content was removed. Disturbances of consciousness recovered soon after the surgery. Aphasia and hemiparesis improved later. Hard clot could be removed completely and safely by this new instrument, SAS & A, at an early stage after a stroke, because of the crushing and washing action.

Aged↗
PubMed1989

Enlarging fundal hemorrhage in Terson's syndrome.

Serial photographs of an enlarging fundal hemorrhage were taken in a 44-year-old man with a subarachnoid hemorrhage. Although clipping surgery was done successfully 17 hours after onset, the patient developed impaired vision on the third postoperative day. Funduscopic examination can document the exact moment when enlarging subhyaloid hemorrhage extends into the vitreous cavity.

Adult↗
PubMed1989

[Aneurysm of the left sinus of Valsalva producing obstruction of the left main coronary artery and aortic regurgitation].

A 50-year-old male was admitted with dyspnea on exertion and palpitation. On physical examination, a grade 2/6 aortic regurgitant murmur was heard at the left sternal border. A chest roentogenogram showed an oval shadow on the left cardiac border. Digital subtraction angiogram, aortogram and coronary arteriogram revealed an unruptured-large aneurysm of the left sinus of Valsalva, which compressed the left main coronary artery and produced aortic regurgitation. Surgical correction consisted of obliteration of the orifice of the aneursym with woven Dacron graft patch, aortic valve replacement using SJM23A, and a saphenous vein bypass from the ascending aorta to the left anterior descending coronary artery. Postoperative studies showed complete obliteration of the orifice of the aneurysm, a patent aorto-coronary bypass graft and no perivalvular leakage. This aneurysm was considered congenital in origin, because of no inflammatory and infectious evidence, negative serologic test for syphilis and no aneurysmal dilatation of the ascending aorta.

Aortic Aneurysm↗
PubMed1988

Presence of crossed corticorubral fibers and increase of crossed projections after unilateral lesions of the cerebral cortex of the kitten: a demonstration using anterograde transport of Phaseolus vulgaris leucoagglutinin.

Brain lesions made during early developmental stages produce more prominent remodeling of synaptic organization than those made in adults. This difference in the extent of neuronal or synaptic plasticity between immature and mature animals may be due to difference in the capacity for axonal elongation. Alternatively, it could be due to the prevention of retraction of exuberant projections present only in the early developmental stages. Aberrant crossed corticorubral projections seen after neonatal hemispherectomy have been ascribed to collateral sprouting. To determine whether these results from the prevention of retraction of crossed fibers, we studied the corticorubral pathway in normal kittens and compared it with that observed after unilateral cortical lesion, using the plant lectin Phaseolus vulgaris leucoagglutinin (PHA-L). One to two weeks after injection of PHA-L, many immunocytochemically labelled fibers were observed in the red nucleus (RN) ipsilateral to the cortical injection. Although very few, labelled fibers were also seen in the RN contralateral to the injection in normal kittens. By contrast, many labelled fibers were seen in the RN contralateral to the injection in lesioned animals. Many growth-cone like axonal endings were also observed. The abundant crossed corticorubral fibers seen in lesioned animals may be ascribed to the increase in the number of fibers crossing the midline towards the contralateral RN or they could be due to increased branching of pre-existing crossed fibers.

Afferent Pathways↗
PubMed1988

Dentin resorption mediated by odontoclasts in physiological root resorption of human deciduous teeth.

Extracted human deciduous teeth undergoing physiological root resorption were fixed with a mixture of formaldehyde and glutaraldehyde and processed for scanning (SEM) and analytical transmission electron microscopy, as well as acid trimetaphosphatase cytochemistry. The granulated tissues, which are rich in multinucleated odontoclasts and capillary vessels, formed various resorption lacunae on the resorbing dentin surfaces. SEM observations of dentin surfaces treated with sodium hypochlorite revealed two types of resorption lacunae: deep, round lacunae in which the peritubular matrix of dentinal tubules was strongly dissolved; and shallow, irregular lacunae with intact peritubular matrix. In trypsin-treated materials, the resorption surfaces were characterized by the presence of numerous collagen fibers in both the peritubular and intertubular matrices, suggesting demineralization of the surface dentin. Odontoclasts were characterized by the presence of abundant mitochondria, perinuclear stacks of Golgi membranes, various lysosomes, numerous endocytotic vacuoles, and a well-developed ruffled border against the resorption lacunae. Most endocytotic vacuoles were distributed in the cytoplasm between the ruffled border and the nuclei. In undemineralized ultrathin sections, the surface dentin of resorption lacunae consisted of collagen fibers and apatite crystals and had a lower packing density than those in unresorbed, deeper dentin. Many apatite crystals were demonstrated to be present in the extracellular channels of the ruffled border and in adjacent endocytotic vacuoles derived from it. Lysosomes located in the perinuclear cytoplasm of odontoclasts contained amorphous dense material and/or a small amount of crystals. An energy-dispersive x-ray microanalysis of apatite crystals in undemineralized sections indicated that the energy spectrum peaks of Ca and P detected from crystals in resorbing dentin were much lower than those in unresorbed dentin. Similarly, lower spectrum peaks of Ca and P were obtained from crystals found in the ruffled border and endocytotic vacuoles of odontoclasts. A slight trace Ca peak also was detected in the amorphous dense material in lysosomes of odontoclasts. The enzyme cytochemistry of lysosomal acid trimetaphosphatase indicated that odontoclasts had intense enzymatic activity in the Golgi membranes, endoplasmic reticulum cisternae, lysosomes, and endocytotic vacuoles. Dense reaction precipitates of enzymatic activity also were found along the dentin surfaces of resorption lacunae occupied by odontoclast ruffled borders.(ABSTRACT TRUNCATED AT 400 WORDS)

Acid Anhydride Hydrolases↗
PubMed1988

H+-K+-ATPase activity in the rat incisor enamel organ during enamel formation.

The enamel organ of growing rat incisors was perfusion-fixed with a mixture of formaldehyde and glutaraldehyde and processed for ultracytochemical demonstration of ouabain-resistant, K+-stimulated p-nitrophenylphosphatase representing the second dephosphorylative step of H-K-ATPase by use of the one-step lead method. Throughout the stages of amelogenesis, the enzymatic activity was found in the plasma membranes, mitochondrial membranes, and lysosomal structures of the cells of stratum intermedium, papillary layer, and ameloblast layer. Gap junctions and desmosomes between these cells were, however, free of reaction product or showed slight precipitates of reaction. The stellate reticulum and the outer enamel epithelium at the stage of enamel secretion were usually negative for reaction. Although secretory, transition, and ruffle-ended maturation ameloblasts showed enzymatic activity at their basolateral cell surfaces, their distal cell surfaces facing the enamel were always free of reaction product. On the other hand, the smooth-ended maturation ameloblasts seldom showed a positive reaction, except in lysosomes and along their basal cell surfaces. An energy-dispersive X-ray microanalysis of reaction products of H-K-ATPase in unosmicated tissue sections demonstrated that they were composed of lead and phosphorus, which had been released during the dephosphorylation of substrate. In cytochemical controls, the enzymatic activity was completely dependent on substrate and potassium ion, resistant to ouabain and levamisole, and inhibited by nolinium bromide, a specific inhibitor of H-K-ATPase. In addition, inorganic trimetaphosphatase as enzymatic marker of lysosome was localized in dark and pale lysosomes, phagosomes, multivesicular bodies, and ferritin-containing vesicles of the ameloblasts and the cells of stratum intermedium and papillary layer. These membrane-bound structures were also positive for H-K-ATPase reaction. These results suggest that: 1) H-K-ATPase functions to maintain an acidic internal pH of lysosomes in the enamel organ cells; and 2) H-K-ATPase localization in the plasma membranes of enamel organ cells is concerned with efflux of protons derived from cytoplasmic water.

4-Nitrophenylphosphatase↗
PubMed1988

Determination of flow and rate constants in a kinetic model of [99mTc]-hexamethyl-propylene amine oxime in the human brain.

The values for flow and rate constants for a kinetic model of [99mTc]-hexamethylpropyleneamine oxime (HM-PAO) distribution in the human brain were determined. The single-pass extraction ratio of HM-PAO was also determined in the rat brain by the indicator diffusion method; a value of 0.90 +/- 0.02 (mean +/- SEM, n = 5) was obtained. Time course data of brain activity and arterial blood activity of the tracer were fitted to a four compartment model: Values of blood flow and the first-order rate constants for backdiffusion of the diffusible tracer from brain to blood (k2), conversion of the lipophilic tracer to the hydrophilic one in brain (k3), and conversion of the diffusible tracer to the nondiffusible one in blood (k5) were determined. Conversion of hydrophilic tracer back to a lipophilic form in both blood and brain was assumed to be negligible during the course of the experiment. The values obtained for blood flow, k2, and k3 were, respectively, 0.40 +/- 0.03 ml/g/min, 0.38 +/- 0.04 min-1, and 0.92 +/- 0.05 min-1 in the gray matter (n = 4), and 0.23 +/- 0.01 ml/g/min, 0.17 +/- 0.01 min-1, and 1.01 +/- 0.05 min-1 in the white matter (n = 2) in patients with cerebrovascular disorder. The k5 value was 1.14 +/- 0.06 min-1 (n = 4). These experimentally determined values agree well with the theoretical ones previously reported by Lassen et al. The results suggest the relative constancy of the k3 and k5 values and the more prominent initial backdiffusion of the lipophilic HM-PAO from brain to blood in high flow regions compared to low flow regions.

Animals↗
PubMed1988

Purification and characterization of lysophospholipase released from rat platelets.

Lysophospholipase released from rat platelets upon activation with thrombin has been purified to near homogeneity by sequential column chromatography on heparin-Sepharose, CM-Sephadex C-50, and TSK gel G2000SW. The final preparation showed a single band with a molecular mass of 32,000 daltons in sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by silver staining. The purified enzyme was heat-labile and inactivated after 5 min at 60 degrees C. It showed a broad pH optimum (pH 6-10) and required a divalent cation, such as Ca2+, for the optimal activity. Appreciable activity, however, was observed in the presence of EDTA. Lysophospholipase activity was inhibited by diisopropylfluorophosphate and dithiothreitol. This enzyme activity was retained by a concanavalin A-Sepharose column and eluted with methyl-alpha-D-mannoside. Treatment of lysophospholipase with peptide: N-glycosidase F gave degraded products, suggesting that this protein contain N-linked carbohydrate chains. The purified enzyme was specific to 1-acyl-sn-glycero-3-phospho-L-serine; none of lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylinositol, and 1-acyl-sn-glycero-3-phospho-D-serine was hydrolyzed appreciably.

Animals↗
PubMed1988

[Electroencephalographic changes during experimental plateau waves].

The present study was designed to induce plateau waves by electrical stimulation of the brain stem and examine the changes in EEG during the plateau waves. Experiments were carried out on 10 adult mongrel dogs which were slightly anesthetized, immobilized and artificially respired. Electroencephalogram (EEG), intracranial pressure (ICP), systemic blood pressure (SBP) and cerebral perfusion pressure were simultaneously recorded on the electromagnetic tape after transorbital puncture of the intracavernous internal carotid artery. EEGs were recorded from cortical electrodes, and were analyzed by a frequency analysis. At the stage of increased ICP, the mesencephalic reticular formation was stimulated. Stimulation parameters, i.e., intensity, duration and frequency, were 0.1 mA, 1 msec and 40 - 50 Hz, respectively. The total duration of each period was 5 seconds. Spontaneous plateau waves occurred in 2 dogs associated with subarachnoid hemorrhage, subdural hematoma and intraventricular hemorrhage. Plateau waves were induced by electrical stimulation in the mesencephalic reticular formation in one of two dogs with spontaneous plateau waves. Twenty-one repetitions of electrical stimulation induced ten plateau waves. Two plateau waves were induced during slow EEG associated with desynchronization of EEG. Eight plateau waves were induced during fast EEG activity with no changes in EEG before and after the stimulation. In addition, plateau waves occurred immediately after short duration (5 seconds) of electrical stimulation. It seems that CBV increases during plateau waves are due to rapidly occurring neurogenic vasodilatation of cerebral vessels, later augmented by increases in cerebral metabolism. In conclusion, plateau waves are produced in a rigid condition within the cranial cavity by stimulation of the brainstem reticular formation which influences cortical activation and cerebral vasodilatation.

Animals↗