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Biomedical subjects

S Tsuji

Publications and source records attributed to S Tsuji.

At least 793 records · Page 44Linked to original sources
PubMed1990

Abnormal glycosphingolipid metabolism in the nervous system of galactosialidosis.

In an autopsy case of galactosialidosis, GM3, GM2, GM1, and GD1a were accumulated in sympathetic and spinal ganglia and grey matter of the spinal cord. Especially, the accumulations of GM3 and GM2 amounted to 41- and 86-fold increases in sympathetic ganglia, respectively, as compared to normal controls. In addition LacCer, GA2 and GA1 were accumulated in sympathetic and spinal ganglia. The accumulations of GM3 and GD1a are considered to be the result of defective lysosomal sialidase activity and the accumulation of GM1, LacCer and GA1 is also considered to be due to decreased beta-galactosidase activity in this disorder. To better understand the possible mechanism of GM2 accumulation, we determined the activity of GM2 synthesizing enzyme (GM3:UDP-GalNAc transferase), as well as hexosaminidase activity, in sympathetic ganglia, but they did not change. Abnormal ganglioside and neutral glycosphingolipid metabolism, as well as sialyloligosaccharide and sialylglycoprotein metabolism, may be involved in the pathogenesis of this disorder.

Biomechanical Phenomena↗
PubMed1990

Enzymic method for the spectrophotometric determination of aspartame in beverages.

A sensitive spectrophotometric method for the determination of aspartame in beverages is described. The method involves the enzymic conversion of aspartame into formaldehyde by the alpha-chymotrypsin-alcohol oxidase system, followed by the formation of a chromophore with 4-aminopent-3-en-2-one. The calibration graph was linear in the range 2.0-30.0 micrograms ml-1 of aspartame. Many common ingredients of beverages do not interfere with the proposed method. The method was applied to the determination of the aspartame content of various real samples, and the results obtained were compared with those given by high-performance liquid chromatography.

Aspartame↗
PubMed1990

Tc-99m HMPAO brain perfusion tomography atlas using a high resolution SPECT system.

Excellent SPECT images of brain perfusion with Tc-99m HMPAO were obtained by the use of a three-head rotating gamma camera SPECT system with high resolution (FWHM 7mm) in a normal volunteer. These images should be clinically effective for evaluating various neurologic disorders. Transverse, coronal, and sagittal sectional HMPAO-SPECT images are correlated with corresponding brain MRI images of the same normal volunteer in this atlas.

Adult↗
PubMed1990

Mucosal blood flow stasis and hypoxemia as the pathogenesis of acute gastric mucosal injury: role of endogenous leukotrienes and prostaglandins.

To clarify the roles of endogenous leukotrienes and prostaglandins in the ethanol-induced gastric mucosal injury, the effect of AA-861 (a selective 5-lipoxygenase inhibitor) and indomethacin (a cyclooxygenase inhibitor) on the ethanol-induced gastric mucosal lesions was investigated in fasted rats. Furthermore, the effect of these agents on the gastric mucosal microcirculatory disturbance induced by ethanol was also investigated using laser Doppler velocimetry and reflectance spectrophotometry. Forty percent ethanol caused mucosal microcirculatory stasis and mucosal hypoxemia, followed by mucosal injury. The pretreatment with AA-861 reduced the mucosal injury and significantly reduced the mucosal congestion and hypoxia induced by 40% ethanol. The pretreatment with indomethacin did not reduce the gastric mucosal damage or influence the mucosal blood flow stasis and the mucosal hypoxemia induced by ethanol. These results suggested that the increase of endogenous leukotrienes after intragastric administration of ethanol is responsible for the mucosal microcirculatory disturbance and mucosal tissue hypoxemia resulting in the mucosal injury, and that the decrease of prostaglandins alone may not play an important role in ethanol-induced mucosal injury.

Animals↗
PubMed1990

Protective effect of PGD2 against ethanol-induced gastric mucosal injury in rats.

The protective effect of prostaglandin D2 (PGD2) in ethanol-, HCl-, or NaCl-induced gastric mucosal injury was investigated. To clarify the mechanism, the gastric mucosal hemodynamics were also investigated using reflectance spectrophotometry and laser Doppler flowmetry in anesthetized rats. PGD2 administered orally significantly reduced the ethanol-induced mucosal injury. Although it did not reach any significance, PGD2 also reduced 0.6 N HCl-induced mucosal damage, and slightly reduced 25% NaCl-induced mucosal damage. Topical application of PGD2 did not affect gastric mucosal hemodynamics at steady state before the administration of necrotizing agent. However, PGD2 significantly improved the gastric mucosal microcirculatory congestion caused by ethanol, and partly improved 0.6 N HCl-induced ischemia. However, it did not improve the 25% NaCl-induced mucosal congestion. The results indicated that PGD2 had a protective effect in the ethanol-induced gastric mucosal injury through the improvement of gastric mucosal microcirculation. However, further investigations are needed to clarify the precise effect of PGD2 in 0.6 N HCl- or 25% NaCl-induced mucosal damage.

Animals↗
PubMed1990

Characteristics of the binding of N-isopropyl-p-[125I]iodoamphetamine in the rat brain synaptosomal membranes.

N-isopropyl-p-[125I]iodoamphetamine (125I-IMP) binding to crude synaptosomal membranes of rat brain was saturable and pharmacologically displacable. Scatchard analysis of binding data revealed an apparent dissociation constant, KD of 56.2 +/- 5.2 microM, and the estimated maximum number of binding sites, Bmax of 7.5 +/- 1.1 nmoles mg-1 protein; and competition studies demonstrated structure activity relationships among structural analogues of arylalkylamines. These findings suggest that the retention mechanism of IMP in the brain is probably associated with saturable binding of IMP to extreme high-density, relatively low-affinity binding sites rather than any of the well-known amine receptors.

Amphetamines↗
PubMed1990

Tetrasialoganglioside GO1b reactive monoclonal antibodies: their characterization and application for quantification of GQ1b in some cell lines of neuronal and adrenal origin(s).

Seven monoclonal antibodies (MAbs) directed to tetrasialoganglioside (GQ1b) were established, purified GQ1b being used for immunization and hybridoma screening. All of the MAbs reacted strongly with GQ1b, although they also reacted with other gangliosides, with different specificities and reactivities. Some MAbs (1H10, 2C7, and 3F4) reacted with GD3, GT1a, GQ1b, and GP1c. MAb 1H4 showed broad specificity. It reacted with GD3, GD1b, GD2, GT1a, GT1b, GO1b, GQ1c, and GP1c. MAbs 7F5, 4E7, and 4F10 recognized GT1a, GQ1b, and GP1c. MAb 4F10 was more specific for GQ1b than the other MAbs. Using MAb 4F10, we determined, by means of an immunoassay, the quantities of endogenous GQ1b in some neuronal and adrenal cell lines, GOTO (human neuroblastoma), Neuro2a (mouse neuroblastoma), and PC12 (rat pheochromocytoma). PC12 and Neuro2a cells contained at least 5.1 X 10(6) and 3.9 X 10(5) molecules/cell of GQ1b, respectively. In contrast, no GQ1b was detected in GOTO cells, which are known for their specific neuritogenic response to this particular ganglioside when exogenously added.

Adrenal Gland Neoplasms↗
PubMed1990

Rapid diagnosis of tuberculous meningitis by polymerase chain reaction (PCR).

Using a rapid and highly sensitive method for the diagnosis of tuberculous meningitis by polymerase chain reaction (PCR), we detected the Mycobacterium tuberculosis genome in CSF of 5 of 6 patients with clinically diagnosed tuberculous meningitis. The genome was not present in CSF from 10 patients with other types of meningitis and 10 normal controls.

Adult↗
PubMed1990

Ultrastructural simultaneous localization of vasoactive intestinal polypeptide immunoreactivity and the acetylcholine-like cation in rat endocrine pancreas.

The ultrastructural co-localization of vasoactive intestinal polypeptide (VIP) and acetylcholine (ACh)-like cation was demonstrated in the rat endocrine pancreas. Immunoperoxidase cytochemical procedure for the detection of VIP was followed by ionic fixation of ACh by silicotungstic acid. All the VIP-immunoreactive nerve endings displayed punctiform precipitates revealing ACh-like cations in the small clear vesicles. Almost all the VIP-immunoreactive nerve terminals were in contact with endocrine A, B or D cells, but not in the close vicinity of blood vessels. Nerve endings devoid of VIP immunoreactivity but containing ACh-like cations were seen either in contact with endocrine cells or in close vicinity to blood vessels. These data suggest that VIP might modulate, concomitantly with ACh, the hormonal secretion of the endocrine pancreas, although the possibility of the neurosecretion of ACh and VIP into the blood vessels should not be excluded. ACh might also control some function of the endothelial cells of blood vessels.

Acetylcholine↗
PubMed1990

Comparison of lactoferrin content in colostrum between different cattle breeds.

Lactoferrin content of colostrum obtained from cows within 24 h after parturition was measured using a single radial immunodiffusion test and was compared among cows of two dairy breeds (Holstein-Friesian, Jersey) and two beef breeds (Japanese Black and Japanese Brown). Average lactoferrin content in colostrum of dairy breeds was 2 mg/ml and in colostrum of beef breeds was .5 mg/ml. Lactoferrin content of colostrum due to lactation number was also different among breeds. In dairy breeds, multiparous cows had lactoferrin content two to three times higher than that of primiparous cows; beef breeds showed no obvious differences between lactation years. Lactoferrin content also varied considerably within breed. In beef breeds, half the cows had values of nearly zero. Transferrin content in colostrum was fairly constant (.9 mg/ml) and was not as variable among and within breeds. There was no correlation between lactoferrin and transferrin contents in colostrum. Examination of cows lacking lactoferrin suggested that transferrin plays an important role as an iron carrier from a cow to her newborn calf.

Animals↗
PubMed1990

Magainin-2 releases histamine from rat mast cells.

The magainins are basic 23 amino acid peptides with a broad spectrum of antimicrobial activity. Their bactericidal effect has been attributed to their capacity to interact with lipid bilayer membranes. We observed histamine release by magainin-2 amide from rat peritoneal mast cells (ED50 = 13 micrograms/ml) but not from human basophils. This histamine-releasing reaction from peritoneal mast cells was due to a secretory rather than cytolytic effect, i.e., release occurred without concomitant liberation of lactic dehydrogenase. Furthermore, the pretreatment of mast cells with magainin-2 amide did not desensitize cells against subsequent challenge with other secretagogues. Maximum histamine release occurred in less than a minute at 25 and 37 degrees C. The addition of Ca2+ was not required for histamine release, although release was enhanced by the addition of 0.3-1 mM Ca2+. The addition of 3 mM Ca2+ or Mg2+ was markedly inhibitory. The presence of Na+ or Cl- ions in the medium was not required for release. Therefore, histamine release is not due to the formation of anion-selective channels in the membrane of mast cells. The results indicated that the characteristics of histamine secretion induced by magainin-2 amide were unlike IgE-mediated release but were similar to the mechanism of release attributed to some other basic peptides and to compound 48/80.

Amino Acid Sequence↗
PubMed1990

[Studies on activated charcoal concerning the determination of sulfate in food coal-tar dyes].

It is very difficult to determine the content of sulfate in food coal-tar dye by the method designated in the "Japanese Standards of Food Additives(V)", because the endpoint on titration is difficult to gauge. We determined the concentration of sulfate in food dye nephelometrically after decolorization with charcoal but obtain different values depending on the kind of charcoal used. Because the adsorbed or eluted sulfate in the various charcoals were dispersed widely, so we tested the sulfate contents in five kinds of charcoals. It was found that all kinds of charcoals eluted or adsorbed sulfate in varying degrees. Therefore no charcoal was found to be satisfactory for use in the sulfate test.

Charcoal↗
PubMed1990

[Molecular genetic analysis of neurologic diseases].

With the recent progress in molecular genetics, our understanding of neurologic diseases on molecular basis has improved tremendously. Molecular analyses of gene mutations in hereditary neurologic diseases bring us not only the identification of mutations but also better understanding of molecular mechanisms involved in the neurologic diseases. We have identified a missense mutation (444Leu----Pro) in glucocerebrosidase gene of a type 2 Gaucher patient. The mutant glucocerebrosidase carrying 444Pro is unstable and degraded rapidly before the mutant protein is targetted to lysosomes. Detailed analysis on the 444Leu----Pro mutations among three phenotypes (types 1, 2 and 3) of Gaucher disease, it has been demonstrated that patients homozygous for the mutation frequently have the neurologic involvement (types 1 and 2). Very recently we have identified a mutation in tRNA(Lys) gene of mitochondrial genome of patients with myoclonus epilepsy associated with ragged-red fibers. The pathophysiologic mechanism with the tRNA(Lys) mutation is considered to be based on the impaired function of tRNA(Lys).

Amino Acid Sequence↗
PubMed1990

[Behçet's disease associated with multiple cerebral aneurysms and downhill esophageal varices caused by superior vena cava obstruction: a case report].

A 62-year-old woman who had suffered from Behçet disease since 1975 was admitted to Kawasaki Municipal Hospital because of severe headache and consciousness disturbance in July 1988. The emergency brain CT scan showed subarachnoid hemorrhage. Despite clipping the neck of the cerebral aneurysm, she died of cerebral herniation. Post-mortem examination revealed four aneurysms on the anterior part of the circle of Willis: 1) at the first bifurcation of the right middle cerebral artery 2) at the bifurcation of the left internal carotid artery 3) at the anterior communicating artery 4) at the left middle cerebral artery. The complete obstruction of the superior vena cava and downhill esophageal varices with no evidence of portal hypertension were also observed. This case had downhill esophageal varices induced by vena caval obstruction as a quite rare symptom of vasculo-Behçet's disease and also complicated with congenital multiple aneurysms of cerebral arteries.

Behcet Syndrome↗
PubMed1990

Non-invasive 31P NMR study on the development of brain membrane of gerbils and jimpy mice, a myelin-deficient mutant.

The broad background resonance observed in the in vivo 31P NMR spectra of adult murine heads was investigated in terms of phosphorus atoms in bone and membrane phospholipids. The broad background resonance was found to be weak in a juvenile and increase with advance of age. Fractionation of adult gerbil heads showed that the broad signal was derived from bone and membrane, of which myelin is the major component. The two origins of the broad background resonance exhibited considerably different line shapes in spectra, which enabled us to extract the membrane component from an intact murine head spectrum (sequential subtraction method). By the use of this method, the development of membrane in gerbil brain at various age grades could be estimated. The membrane component was shown to be suppressed in a mutant mouse, jimpy, which has a deficiency in myelin formation ability. Furthermore, the value of T1 of the membrane component was estimated to be 0.9 sec, which was in good agreement with previously reported values for excised brain.

Animals↗
PubMed1990

A common mitochondrial DNA mutation in the t-RNA(Lys) of patients with myoclonus epilepsy associated with ragged-red fibers.

Nucleotide sequence analyses of muscle mitochondrial DNA (mtDNA) from a patient with myoclonus epilepsy associated with ragged-red fibers (MERRF) revealed 33 single base substitutions, including 23 in coding regions for mitochondrial polypeptides and 10 in non-coding regions, as compared with the normal human mtDNA sequence. Three substitutions, in COI, ND4, and Cytb, would result in amino acid substitutions, which are conserved among species. Of three patients with MERRF, all had an identical A to G base substitution only at nucleotide position 8344 in the t-RNA(Lys) region. The substitution was not found in 15 controls. Various degrees of the combined enzymic defects in the oxidative phosphorylation system of mitochondria were found in the MERRF patients. The defects could be explained by altered function or processing of the mutant t-RNA(Lys). This mutation in the t-RNA(Lys) is the most probable cause of MERRF.

Adult↗