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Biomedical subjects

J Takahashi

Publications and source records attributed to J Takahashi.

At least 19 recordsLinked to original sources
PubMed1992

Concentrations of serotonin and its related substances in the cerebrospinal fluid in patients with Alzheimer type dementia.

We studied concentrations of free and total serotonin (5-hydroxytryptamine, 5-HT) and its related substances in the cerebrospinal fluid from patients with Alzheimer type dementia (ATD) compared with controls. In ATD patients, concentrations of total 5-HT, tryptophan, 5-hydroxytryptophan (5-HTP), melatonin, kynurenine, and 3-hydroxykynurenine decreased significantly. The rate of concentration of tryptophan metabolites to that of tryptophan was significantly reduced for total 5-HT and 3-hydroxykynurenine only. The 5-hydroxyindoleacetic acid (5-HIAA)/5-HT ratio was significantly larger in ATD patients than in controls. The greater reduction in the 3-hydroxykynurenine concentration (81% vs. controls) than in the total 5-HT concentration (51% vs. controls) suggests that the metabolism of tryptophan to 5-HT and 3-hydroxykynurenine is in favor of 5-HT.

Aged↗
PubMed1992

Decrease in plasma GLP-1 immunoreactivity in starved rats.

To determine whether starvation affects the metabolism of glucagon-like peptide-1 (GLP-1), we measured the plasma levels of proglucagon-derived peptides and the biosynthesis and posttranslational processing of proglucagon in groups of six rats starved for 1, 3 and 5 days. The plasma levels of GLP-1 immunoreactivity (GLP-1 IR) and glucagon-like immunoreactivity (GLI) decreased during starvation reaching 79 and 56% of the respective control values by day 5 (P less than 0.05 and less than 0.01 vs control). The same is true of the plasma IRI level. The ileal contents of GLP-1 IR and GLI were 50.8 +/- 3.8 pmol/g wet weight and 161.8 +/- 13.2 pmol/g wet weight, respectively, on day 5 of starvation, which were significantly lower (P less than 0.01) than the respective values of 94.8 +/- 16.6 pmol/g wet weight and 262.7 +/- 28.1 pmol/g wet weight in control rats. However, the pancreatic contents of proglucagon-derived peptides tended to increase during starvation, although their increases were not statistically significant. No significant change in the posttranslational processing of proglucagon was detected during starvation. The decrease in the ileal proglucagon-derived peptides content was not associated with a decrease in intestinal proglucagon mRNA transcripts. These results suggested that decreased synthesis of proglucagon-derived peptides by the intestine was largely responsible for the reductions in their circulating levels in starved rats.

Analysis of Variance↗
PubMed1992

Dose-responsive effect of radiotherapy on the tumor uptake of L-[methyl-11C]methionine; feasibility for monitoring recurrence of tumor.

The L-[methyl-11C]methionine [( 11C]Met) uptake by rat AH109A tumor was decreased irradiation-dose dependently from the control to 5, 10 and 20 Gy. After 10 Gy irradiation, the [11C]Met uptake decreased earlier than the tumor volume reduction, and later, it significantly increased earlier than the recurrent growth. Double tracer autoradiography with [14C]Met and 4-[18F]fluoroantipyrine showed a decrease in the [14C]Met tumor uptake without change of blood flow after irradiation. The [11C]Met uptake representing amino acid metabolism is a sensitive indicator for monitoring radiotherapeutic effect on tumor.

Animals↗
PubMed1992

Cell kinetic study of murine jejunal crypts during multiple doses per day.

We studied cell kinetics of mouse jejunal crypts during multiple fractionation using double labeling methods. Mice were irradiated to the total body once a day or twice a day. Fraction size was 2 Gy. Overall time was 1, 3 and 5 days. Labeling index (LI), duration of S phase (Ts) and potential doubling time (Tpot) were assessed next morning following the irradiation schedule. Mice were administered both bromo-deoxyuridine (BrdUrd) and 3H-Thymidine ([3H]dT) with a constant interval. Removed jejunum were stained with immuno-histochemistry and, then, processed for autoradiography. BrdUrd and [3H]dT LIs were the same and were increased up to 5 days despite the fractionation schedule. After 1 day following 2 fx/day, both Ts and Tpot decreased significantly. For 1 fx/day treatment, neither Tpot nor Ts changed. After 5 day following 1 and 2 fx/day, both Ts and Tpots were the same and Tpots were significantly shorter than that obtained from control. It seems that proliferative responses between 1 and 2 fx/day were different.

Animals↗
PubMed1992

N-(F-18)-fluoroacetyl-D-glucosamine: a new positron labeled pharmaceutical for cancer study.

In order to evaluate the role of hexosamine metabolism in tumor tissue, we studied the biodistribution of N-(F-18)-fluoroacetyl-D-glucosamine (FAGlu) in male Donryu rats bearing poorly differentiated hepatomas (AH109A and AH272). Compare with the former result of the high tumor uptake of FAGlu in C3H/He mice bearing well differentiated spontaneous hepatoma, the tumor uptakes of FAGlu in these tumors showed the lower values. This suggested that spontaneous hepatoma maintained a high activity of glucosamine metabolism, while poorly differentiated hepatoma had little activity. Metabolism of glucosamine in tumor tissue may be another marker for characterizing tumors. We also discuss the tissue distribution of new F-18 labeled hexosamines, N-(F-18)-fluoroacetyl-D-mannosamine and N-(F-18)-fluoroacetyl-D-galactosamine in tumor bearing rats.

Acetylgalactosamine↗
PubMed1992

Three dimensional shape measurement of teeth (2). CAD to produce crown considering occlusion.

Use of a CAD program to design the shape of a crown, restoration of 6 molar was studied. Stone models of 5 to 7 molars with 6 prepared die for crown and a complete 6 crown which was applied for restoration were measured. The 6 crown data were adapted on the 6 die, and adjusted with 5 and 7 proximal teeth. The coordinates of the data of 6 were then transferred to that of the 6 die. The ends of the adapted crown data were linked with the margin of 6 die. Further the occlusal condition with antagonistic tooth was adjusted by applying the FGP (functionally generated path) technique. FGP was recorded on bite wax and measured. Comparing FGP record and adapted crown, modulation of the occlusal surface was accomplished.

Computer-Aided Design↗
PubMed1992

[Amrinone reverses cardiac depression by enflurane in the dog].

To evaluate the interaction of amrinone with inhalational anesthetics, cardiovascular effects of amrinone were investigated in nine mongrel dogs anesthetized with enflurane. Each dog received enflurane and amrinone in the following sequence: 1) 2% enflurane alone, 2) continuous infusion of 20 micrograms.kg-1.min-1 during enflurane, 3) 40 micrograms.kg-1.min-1 infusion during enflurane. Amrinone 40 micrograms.kg-1.min-1 during enflurane anesthesia improved the maximum left ventricular dP/dt, stroke volume and decreased effective arterial elastance (Ea) without changes in left ventricular end-diastolic pressure and heart rate. Left ventricular pressure (LVP) and systolic femoral arterial pressure were stable, but diastolic femoral arterial pressure decreased significantly from enflurane anesthesia alone. These parameters at 20 micrograms.kg-1.min-1 of amrinone infusion during enflurane showed the same tendency with 40 micrograms.kg-1.min-1 infusion but not significantly different from enflurane alone. This result suggests that amrinone may be beneficial in the patients with depression of cardiac performance during anesthesia.

Amrinone↗
PubMed1991

Trigeminal neuralgia caused by compression from arteries transfixing the nerve. Report of three cases.

The authors present three patients with trigeminal neuralgia due to compression by an artery that transfixed the sensory root of the fifth cranial nerve. These cases represented 0.8% of 384 patients with trigeminal neuralgia treated by microvascular decompression at the authors' clinic during the past 12 years. In the remaining 381 cases, the compressing vessels were successfully removed from the trigeminal nerve without much difficulty, for an initial cure rate of 94.3%. In the three cases reported, however, the compressing artery penetrating the nerve could not easily be maneuvered away from the nerve. In the first two cases, partial rhizotomy perpendicular to the axis of the nerve at the site of arterial transfixion made it possible to separate the artery from the nerve. However, these two patients developed postoperative facial sensory impairment. In the third case, rhizotomy was performed longitudinal to the axis of the nerve at the site of arterial transfixion, making it possible to reposition the artery peripherally beyond the root entry zone of the nerve without causing any postoperative sensory deficits of the face. No recurrent pain has developed in more than 2 1/2 years since surgery in any of these three cases. When performing microvascular decompression surgery on patients in whom the compressing artery penetrates the nerve, the technique used in our third patient is the procedure of choice.

Aged↗
PubMed1990

Effect of a synthetic norepinephrine precursor, L-threo-3,4- dihydroxyphenylserine on the total norepinephrine concentration in the cerebrospinal fluid of parkinsonian patients.

We studied the effect of a synthetic norepinephrine precursor, L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on the total (conjugated and unconjugated) norepinephrine concentrations in the cerebrospinal fluid (CSF) of 6 parkinsonian patients with freezing phenomenon. The total norepinephrine concentrations in the CSF increased from 5- to 75-fold after treatment with L-threo-DOPS. The degree of increase in the norepinephrine (NE) concentrations was closely correlated to the dosage of L-threo-DOPS. The freezing phenomenon improved in 3 out of 6 patients.

Carbidopa↗
PubMed1990

[Surgical management of syringomyelia associated with Arnold-Chiari malformation, primary IgA deficiency and chromosomal abnormality--a case report].

A rare case of syringomyelia associated with Arnold-Chiari malformation, primary IgA deficiency and sex chromosomal abnormality is reported. A 26-year-old Ethiopian black male was admitted with a complaint of hypalagesia of his left arm and face for 10 years. Neurological examination on admission revealed dissociated sensory loss of his left arm and face. Mild motor weakness of his hand and rotatory nystagmus on left gaze were also noticed. Plain craniogram of lateral view showed small posterior cranial fossa with low positioned inion and platybasia. MRI with T1-weighted images in sagittal plane revealed tonsillar herniation reaching C1 and syrinx extending from C2 to lumbar region. Although no episode of infectious disease nor allergy were experienced, blood analysis disclosed low serum level of IgA (7 mg/dl). The values of other immunoglobulins were within normal range. IgA in saliva was not detected, too. According to the clinical history and symptoms, a diagnosis is of primary asymptomatic IgA deficiency was obtained. Karyotype analysis showed inversion of Y chromosome. In an attempt to avoid anaphylactic shock on blood transfusion in a patient with IgA deficiency, autologous blood was prepared before surgery. Decompressive craniectomy of the posterior fossa with posterior arch of C1 and C2 was performed together with syringosubarachnoid shunt at Th 6-7 level. Postoperative course was successful and slight improvement of sensory disturbance was obtained. No respiratory or wound infection was occurred. The association of these three anomalies is very rare and genetical relationship is not known. From surgical point of view, it is conceivable that preoperative management in a case of asymptomatic IgA deficiency is uneventful.

Adult↗
PubMed1990

Decreased susceptibility of lined human gliosarcoma cells to lymphokine-activated killer cell cytolysis by gamma-interferon treatment.

The susceptibility of the established cultured gliosarcoma line GI-1 to lymphokine-activated killer (LAK) cells was analyzed with and without interferon (IFN)-gamma treatment of target GI-1 cells. IFN-gamma treatment decreased the susceptibility of GI-1 cells to LAK cell cytolysis in a dose-dependent manner. Acid treatment of GI-1 cells increased their susceptibility to cytolysis compared with untreated cells. IFN-gamma treatment and acid treatment of GI-1 cells respectively increased and decreased the expression of class I HLA antigens on GI-1 cells. The susceptibility of GI-1 cells to LAK cell cytolysis and their expression of HLA class I molecules were inversely correlated. Subpopulation depletion experiments on the LAK cells with monoclonal antibodies and complement revealed that phenotypically natural killer type (CD16+) cells had a high cytotoxic activity against untreated GI-1 cells but a relatively low activity against IFN-gamma-treated GI-1 cells in both the precursor and effector phases. On the other hand, phenotypically T-type (CD3+) cells did not show these tendencies at all in both the precursor and the effector phases.

Antigens, Differentiation↗
PubMed1990

Insolubilized properties of UV-irradiated CO3 apatite-collagen composites.

To examine the response to biological hard tissues, a carbonate-containing hydroxyapatite with chemical composition and crystallinity similar to those of bone was synthesized at pH 7.4 and 60 degrees C. The apatite powder was mixed with collagen solution, whose antigenicity had been removed by enzymatic treatment, and formed into apatite-collagen pellets. After insolubilization by UV-irradiation for 4 h, the composites showed remarkably reduced disintegration and maintained their shape under 3.6 MPa of stress after 1 wk incubation in 0.9% NaCl solution. They showed good biocompatibility when implanted beneath the periosteum cranii of rats. The UV-irradiated sample kept its features well and was packed with newly created material 3 wk after implantation.

Animals↗
PubMed1990

Mammary carcinoma with pulmonary metastasis in a sow.

Mammary adenocarcinoma was diagnosed in a 3-year-old Landrace sow with prolonged infertility, anorexia and progressive emaciation after parturition. Gross examination confirmed a large tumour in the left anterior mammary gland with metastatic nodules on the pleura and in the parenchyma of lung. Microscopically, the tumour consisted mainly of solid adenomatous proliferations with numerous mitotic figures. Irregular glandular structures, solid nests of polygonal tumour cells without polarity and nests consisting of glandular, cribriform and solid portions were evident in dense fibrous stroma. Immunostaining revealed keratin in the tumour cells.

Animals↗
PubMed1990

Casting pure titanium into commercial phosphate-bonded SiO2 investment molds.

Pure titanium was cast into five different phosphate-bonded SiO2 investment mold materials (at 350 degrees C) with an argon-arc melting and pressure casting machine. The mesh castability, the fit of the MOD inlay castings, and the Knoop hardness and the micro-structure in cross-sections of castings were examined. The setting and thermal expansion, the compressive strength, and the X-ray diffraction analysis of the investments were also measured. The castability, the fit, and the thickness of the reacted layer differed in degree among these investments, in spite of the same phosphate-bonded SiO2-type investment. A significant correlation was obtained between the thermal expansion (at 350 degrees C) and the casting accuracy.

Analysis of Variance↗
PubMed1990

Origin of abomasum gas in the cows with displaced abomasum.

The gas composition of the rumen and the abomasum were investigated in 71 cows including 25 cows with displaced abomasum. The ratio of methane (CH4) to CO2 in the abomasum gas was higher than that in the rumen. In the incubated mixtures of fresh rumen fluid, CH4 was detected at a high concentration, while a small amount of CO2 and CH4 was found in incubated mixtures of fresh abomasum fluids. Hence, it was suggested that the gas in the abomasum originated not from the abomasum itself but from the rumen. In cows fed with mixed roughages and concentrates, the rumen CO2:CH4 ratio was higher compared with cows fed with roughages alone. Marked changes in rumen gas composition were presumed to be associated with changes in abomasum gas composition. Consequently, it is possible that feeding a large quantity of concentrates may increase the flow rate of the ingesta through the forestomach, so that the return rate of gas separated from the ingesta in the abomasum to the forestomach may also increase. Therefore, the frequent accumulation of a large amount of gas with concomitant changes in the total volatile fatty acid (VFA) concentration in the abomasum caused abomasal atony and subsequently displaced abomasum.

Abomasum↗
PubMed1990

[Solitary cerebral varix. Case report].

A 69-year-old male presented with a 4-month episode of tonic seizures of the right arm and leg. Neurological examination revealed no abnormal findings. In the electroencephalogram, sharp wave trains were seen dominantly in the left frontal region. Computed tomography scans showed a spotty hyperdense lesion in the left insular area with minimal enhancement. Left carotid angiogram demonstrated no abnormalities in the arterial and capillary phases. In the venous phase, however, a varicose dilatation of the posterior insular vein was found, which was also noticed in the delayed phase. Magnetic resonance T1-weighted images failed to detect the lesion, but T2-weighted images showed a slight signal focus in the same area. After administration of 300 mg of phenytoin daily, the frequency of attacks markedly decreased and the patient was kept under close outpatient observation.

Aged↗
PubMed1990

[The study on retention of adhesive restoration].

Although the prognoses of the adhesive bridges are practically satisfactory, some disconnections have been reported. Physical bite, twisting and tearing forces are considered to be the causes for these disconnections. Paired natural human teeth; 2 incisal and 2 molar teeth, were embedded in cold cured resin for fatigue test and axial reduction was slightly performed. Cast bridges which were designed to come to 30 mm2 in every abutment and to resemble clinical design, were made from two kinds of metal; Ni-Cr alloy and Ag-Pd-Au alloy, and adhered with teeth by Panavia EX (Kurarey Co. Ltd.). Incisal bridges were disconnected easier than molar bridges in the fatigue test. There was no significant difference between 2 kinds of metal. With stereoscopic microscope, cohesive fracture of resin was observed on the region which was farthest from supporting point of fatigue force in incisal bridges. Dimple patterns characteristically in fatigue fracture were also observed in some cases. In modified tensile test of incisal teeth using Ni-Cr alloy, force point was given far 1 mm & 12 mm apart from approximal surface, and various twisting and tearing forces were loaded in 12 mm cases. The cases loaded by higher twisting and tearing forces had significantly smaller bond strength.

Chromium Alloys↗