Biomedical subjects

T Sumi

Publications and source records attributed to T Sumi.

At least 73 records · Page 4Linked to original sources

PubMed1996

Determination of the 8-methyl ether of xanthurenic acid in human serum by high-performance liquid chromatography with fluorescence detection.

We developed a simple and sensitive assay for the 8-methyl ether of xanthurenic acid in serum by high-performance liquid chromatography with fluorescence detection (excitation at 340 nm, emission at 450 nm). The compound under study in serum samples was extracted with Sep-Pak C18 cartridge and the extract was applied to an octadecylsilane-bonded column (Nucleosil 5C18, 150 x 4 mm I.D.). The mobile phase used was a mixture of 0.05 M sodium acetate buffer (pH 6.0), containing 5 mM sodium 1-octanesulfonate and 0.1 mM Na2EDTA, and acetonitrile (93:7, v/v). The 8-methyl ether of xanthurenic acid from serum samples was sufficiently separated to be clearly distinguishable. The quantification limit was 2 x 10(-14) mol, which was sensitive enough to detect 8-methyl ether of xanthurenic acid in serum from normal subjects. The method was applied to samples from patients with deficiency in tryptophan metabolism, xanthurenic acid/3-hydroxy kynurenineuria and showed a striking elevation in serum 8-methyl ether of xanthurenic acid.

Amino Acid Metabolism, Inborn Errors↗

PubMed1995

Anemia-inducing substance from plasma of patients with advanced malignant neoplasms.

Patients with advanced malignant neoplasms develop anemia and immunosuppression. During an attempt to identify the causes, we have found that plasma from such patients makes RBCs more fragile in hypotonic buffer, according to results obtained with a coil planet centrifuge. Plasma from these patients suppresses mitogen-stimulated lymphocyte proliferation. In this study, we identified the substance with these effects as a protein. During two-dimensional gel electrophoresis, two isomers with M(r) 50,000 and slightly different isoelectric points near 6.0 were found. Cell fractionation showed that these proteins were in both the cytosol and the nuclear fraction of cells in neoplasms. Another protein with the same antigenicity and a M(r) 100,000 found in the nuclear fraction of cells in neoplasms.

Anemia↗

PubMed1995

Induction of teratocarcinoma F9 cell differentiation with cis-diammine dichloroplatinum(II) (CDDP).

cis-Diammine dichloroplatinum(II) (CDDP) is the salt of a platinum compound which has been noted to have a wide spectrum of activity against malignant disorders. We have studied the effects of CDDP on embryonal carcinoma F9 cell differentiation. In the presence of this agent in vitro, the cells showed rapid morphological changes, a marked increase in the mRNA expression of various differentiation markers accompanied by a loss of tumorigenicity. These results indicate that the differentiation of F9 cells is induced with CDDP.

Animals↗

PubMed1995

Effects of protein phosphatase inhibition by okadaic acid on the differentiation of F9 embryonal carcinoma cells.

Okadaic acid, a protein phosphatase inhibitor, is a strong tumor promoter which apparently activates protein phosphorylation. To examine the role of protein phosphatases in stem cell growth and differentiation, embryonal carcinoma F9 cells were treated with okadaic acid. In the presence of this agent, the cells showed rapid morphological changes and arrest of proliferation at the M phase of the cell cycle, accompanied by a marked increase in the mRNA expression of various differentiation markers. Okadaic acid induced rapid increase in the mRNA levels of both c-jun and junB and results indicate that the inhibition of phosphatase by okadaic acid induces apparent activation of protein phosphorylation and may cause the expression of differentiation marker genes in F9 cells via the activation of AP-1.

Animals↗

PubMed1995

The kinetics of induction of Hox1.6 and C-jun mRNA during three different ways of inducing differentiation in teratocarcinoma F9 cells.

Changes in Hox1.6 and c-jun gene expression were examined upon F9 cell differentiation that was induced by three independent methods: a drug treatment with retinoic acid (RA), that with sodium butyrate (NaB), and a genetic approach using the ts mutant. To obtain further information on the mechanism of teratocarcinoma cell differentiation we have examined the kinetics of the induction of Hox1.6 and c-jun mRNA whose gene products have been demonstrated to have specific roles in gene regulation. Expression of Hox1.6 mRNA was induced more rapidly than c-jun mRNA by all the above three inducing methods. Furthermore, protein synthesis was not required for the induction of Hox1.6 mRNA as well as of c-jun mRNA synthesis in all three methods. The data suggested that the transcriptional increase in the Hox1.6 mRNA was a primary response and could play an important role in F9 cell differentiation.

Butyrates↗

PubMed1994

Characterization of a deaminated neuraminic acid-containing glycoprotein from the skin mucus of the loach, Misgurnus anguillicaudatus.

Using NMR spectroscopy and mass spectrometry, the major sialic acid of the skin mucus of the loach, Misgurnus anguillicaudatus was found to be 3-deoxy-D-glycero-D-galacto-2-nonulosonic acid (KDN). We have subsequently devised a method to isolate a KDN-containing glycoprotein preparation from loach skin mucus. The method involves the sonication of the skin mucus with 0.05 M Tris-HCl, pH 8.0, to solubilize the glycoprotein, followed by DE52-cellulose chromatography of the extract, Nuclease P1 treatment, and Sepharose CL-4B gel filtration. The purified glycoprotein preparation was found to contain 38.5% KDN, 0.4% NeuAc, 24.6% GalNAc, 3.3% Gal, and 28.2% amino acids (w/w). The amino acid composition of this glycoprotein preparation revealed that it is unusually rich in Thr, and 6 amino acids, Thr, Ser, Glu (or Gln), Pro, Gly and Ala, account for 83% of the total amino acids. This glycoprotein is extremely poor in Cys, Met, Tyr, Phe, Arg, and Trp. Treatment of this glycoprotein with alkali resulted in the destruction of 83% of Thr suggesting that most of the sugar chains in this glycoprotein are linked through Thr. Alkaline borohydride treatment of 100 mg of the glycoprotein preparation, followed by Sephadex G-25 (superfine) gel filtration, yielded two major oligosaccharide alditols, I (15.4 mg) and II (15.6 mg). Using liquid secondary ion mass spectrometry and methylation analysis, I was identified to be KDN alpha 2-->6GalNAc-ol and II, KDN alpha 2-->6(KDN alpha 2-->3)-GalNAc-o1. KDN alpha 2-->6GalNAc is structurally similar to NeuAc alpha 2-->GalNAc found in ovine submaxillary glycoprotein while II represents a novel structure which contains two sialic acids linked to a GalNAc through both alpha 2-->3 and alpha 2-->6 linkages. This structure has never been found in mucin type glycoproteins including mammalian epithelial mucin glycoproteins. This is the first report of the presence of a mucin type glycoprotein which contains KDN instead of NeuAc or NeuGc in fish skin mucus.

Amino Acids↗

PubMed1994

Comparison of chorionic villus sampling and amniocentesis: current status of prenatal diagnosis in Japan.

Data were tabulated and compared for cases involving prenatal diagnostic procedures performed in the 8 years between January 1985 and December 1992. Of a total of 2781 pregnancies, 2546 cases (91.5 per cent) were diagnosed by amniocentesis, and 235 (8.5 per cent) by chorionic villus sampling (CVS). These findings reflect the fact that amniocentesis has taken deep root as the prenatal diagnostic procedure widely acknowledged by society, whereas even the existence of CVS has yet to be generally recognized. Analysis of our clinical and laboratory results and complication rates, however, suggests that CVS is a safe and accurate alternative to amniocentesis which should and can be positively presented to all patients who are candidates for prenatal diagnosis.

Amniocentesis↗

PubMed1994

[DNA ploidy and proliferating cell nuclear antigen positivity rate as predictive indication of effectiveness of preoperative radiation].

We compared histological effects following radiotherapy in relation to the DNA ploidy pattern and the proliferating cell nuclear antigen (PCNA) positivity rate in 37 patients with rectal cancer who underwent preoperative radiation therapy. Twelve of 23 cases in which the PCNA positivity rate before irradiation was more than 25% showed the effectiveness of radiotherapy (52.2%), against 2 of 6 cases with a rate of less than 25%. Cases in which the rate was more than 25% tended to show more effectiveness. Seventeen of 23 cases in which the PCNA positivity rate was more than 25% showed a decrease in PCNA positivity rate (73.9%). The rate in 6 cases showed no change, and no cases had an increase. In particular, in 12 cases in which the PCNA positivity rate was more than 55%, half showed effectiveness, and the PCNA rate decreased 20% on average. The PCNA positivity rate tended to decrease as a result of irradiation, and especially in diploid cases there were significant differences in the rate before and after irradiation. We suggest that cases in which the PCNA positivity rate is more than 55% with diploid DNA pattern would show most effect. The effects of irradiation could be predicted with biopsy materials and by measuring the DNA ploidy pattern and the PCNA positivity rate.

Adenocarcinoma↗

PubMed1993

Suppression of tumorigenicity in temperature-sensitive mutants of embryonal carcinoma cells by induction of cell differentiation at non-permissive temperature.

The temperature-sensitive (ts) mutants of cell differentiation derived from the mouse teratocarcinoma cell line F9, when exposed to non-permissive temperature, undergo stem-cell differentiation concomitant with a transient retardation of cell-cycle progression. By incubating these mutant strains at non-permissive temperature, we were able to study the relationship between cell differentiation and tumorigenicity. Upon exposure to non-permissive temperature, the mutant cells undergo extensive differentiation and lose their ability to initiate tumors in vivo, but retain their in vitro proliferative potential. Our data suggest that the loss of tumorigenicity is not caused by altered proliferative potential, but rather by cell differentiation. We therefore suggest that the loss of proliferative potential and the onset of cell differentiation in teratocarcinoma F9 cells are 2 independent events which can be genetically dissected, and that there is (a) crucial step(s) in the differentiation pathway at which these ts mutant cells lose their tumorigenicity.

Alkaline Phosphatase↗

PubMed1993

Changes in Hox1.6, c-jun, and Oct-3 gene expressions are associated with teratocarcinoma F9 cell differentiation in three different ways of induction.

To obtain information on the mechanism of teratocarcinoma cell differentiation, the expression of genes having a specific role in gene regulation was examined using three different methods of inducing differentiation: drug treatments with retinoic acid (RA) and sodium butyrate, and a genetic approach using ts mutants. The RAR-beta and MK genes were induced specifically by RA treatment, which indicates that these two genes are solely RA responsive. By contrast, a change in c-jun, Hox1.6, and Oct-3 gene expression was observed in all three methods of F9 cell differentiation. These findings suggest that these three genes, whether down-or up-regulated, play an important and key role during teratocarcinoma cell differentiation.

Animals↗

PubMed1993

The induction of jun genes during the reversible changes induced with sodium butyrate on the differentiation of F9 cells.

Sodium butyrate (NaB) induces the phenotypic changes and differentiation markers in embryonal carcinoma F9 cells (Kosaka et al., Exp. Cell Res. 192, 46, 1991). However, the effects are rapid and reversible and different from those induced with retinoic acid (RA). We examined the expression of jun genes during differentiation induced with NaB and compared it with that of RA induction. Although c-jun expression was induced with RA, rapid and predominant induction of junB expression was specifically observed with NaB, which is regulated by both transcriptional and post-transcriptional mechanisms. These results suggest that the mechanism of differentiation induced with NaB differs from that of RA; the former may be mediated by the junB gene and the latter by c-jun.

Animals↗

PubMed1993

[Different effects of chronically administered phenobarbital on amygdaloid- and hippocampal-kindled seizures in the cat].

Kindling model has been regarded as an experimental model for partial seizure with secondary generalized convulsion in human epilepsy. A number of pharmacological studies have been carried out to evaluate antiepileptic effects of conventional anticonvulsants on kindled seizures, mainly using amygdala kindled model. However, it is known that hippocampus is a more important site for human temporal epilepsy. It should therefore be considered appropriate to evaluate effects of antiepileptic drugs, not only on amygdaloid- but also on hippocampal-kindled seizures. In the present study, effects of chronically administered phenobarbital (PB) on amygdaloid- and hippocampal-kindled seizures were investigated. In the first session, cats were orally administered 6 mg/kg of PB for 15 days to obtain the serum level between 15 micrograms/ml and 25 micrograms/ml (optimal level for human epileptic seizure), then stimulation was carried out once a day for the following five days with suprathreshold stimulation intensity (100 microA higher than generalized seizure triggering threshold). For evaluation of drug efficacy, duration of afterdischarge and seizure severity were determined. After the end of session 1, session 2 started with 12 mg/kg of PB for 35-50 micrograms/ml serum level (subtoxic level) and continued in the same manner as stated above. PB was proved to be more effective for hippocampal- than for amygdaloid-kindled seizures. Generalized convulsions were easily suppressed in the level of 15-25 micrograms/ml and afterdischarge was totally suppressed in 33% of cats in the level of 35-50 micrograms/ml in the hippocampal-kindled group. However, amygdaloid-kindled seizures were more resistant to PB. It was difficult to suppress generalized convulsion in the level of 15-25 micrograms/ml, and total suppression of afterdischarge was extremely rare even in the higher serum level in amygdaloid-kindled cats. In addition, cats requiring a smaller number of stimuli to the completion of kindling tended to show more marked drug-resistance. Such tendency could be seen in both groups, although, more distinct in amygdaloid-kindled cats. Also evaluated were effects of PB on the secondary site kindled-seizures and it was shown that the potency of PB was less manifest in secondary site amygdaloid seizures than in primary site hippocampal seizures. These data show that the drug efficacy in the kindling model depends on the stimulated brain region as well as animals predisposition probably related to rapid acquisition of epileptogenesis. The intractability of temporal lobe epilepsy might be related to the site of epileptic focus and predisposition of patients as well.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗

PubMed1993

Solitary eosinophilic granuloma of bone occurring in the buccal mucosa: report of a case.

Eosinophilic granuloma of bone is not uncommon in the craniofacial region (Anderson and kissane, 1977), and it sometimes occurs in organs such as the lung, stomach and spleen. However there are only few reports on solitary eosinophilic granuloma of bone occurring in oral soft tissue. In this report, we describe a case of eosinophilic granuloma of bone occurring in the soft tissue of a 40-year-old woman.

Adult↗

PubMed1992

Amitriptyline inhibits striatal efflux of neurotransmitters via blockade of voltage-dependent Na+ channels.

Amitriptyline, a tricyclic antidepressant, almost completely inhibited veratridine- or scorpion toxin-evoked efflux of endogenous dopamine (DA) and gamma-aminobutyric acid (GABA) from rat striatal slices without any effects of 30 mM K+ or 4-aminopyridine on basal and evoked efflux. The effects of amitriptyline on glutamate efflux were comparable to those on DA or GABA efflux. These effects of amitriptyline can be well explained by its blockade of voltage-dependent Na+ channels and may be independent of other activities of this drug such as re-uptake inhibition of monoamines and blockade of K+ channels.

Amitriptyline↗

PubMed1992

Estimation of right ventricular volume by modified echocardiographic subtraction method.

To evaluate the accuracy and clinical utility of right ventricular volume estimated by a modified echocardiographic subtraction method versus Krebs' original subtraction method, an experiment was performed on hearts excised from 25 animals (dogs, pigs, and cows) followed by a clinical study of 41 patients with heart disease. Right ventricular volume was measured by subtracting the left ventricular volume from that of the whole heart based on echocardiographic apical two- and four-chamber views by means of the area-length method. In the animal heart study, the coefficient of variation between the right ventricular volume estimated by the modified method and the true volume was +/- 13%. The regression equation was y = 0.94x + 4.15 (r = 0.987, p less than 0.001) and showed good correlation, whereas the right ventricular volume obtained by the original method underestimated the true volume (coefficient of variation = +/- 25%, y = 0.59x + 1.11; r = 0.976, p less than 0.001). In the clinical study, the coefficient of variation between right ventricular volume estimated by the modified echocardiographic method and RV volume estimated by radionuclide ventriculography was +/- 15%. The regression equation was y = 0.80x + 13.3 (r = 0.935, p less than 0.001). This correlation was better than that obtained by the original method (coefficient of variation = +/- 16%), where the regression equation was y = 0.60x + 2.43 (r = 0.888, p less than 0.001). Thus the accuracy of the modified subtraction method was validated, and this method showed a better correlation than the original method both experimentally and clinically.

Adolescent↗

PubMed1992

Expression of c-kit protooncogene is stimulated by cAMP in differentiated F9 mouse teratocarcinoma cells.

Protooncogene c-kit, a transmembrane tyrosine kinase receptor, was recently shown to map to the dominant white spotting locus (W) of the mouse. W mutations affect melanogenesis, gametogenesis, and hematopoiesis during development and in adult life. In order to determine the regulation of the c-kit gene in cell differentiation, we investigated its expression during the differentiation of F9 cells. Undifferentiated F9 cells and F9 cells treated with retinoic acid (RA) alone or dbcAMP alone showed little expression of c-kit mRNA if any. The subsequent addition of dbcAMP to F9 cells treated with RA markedly increased the expression of c-kit mRNA. Furthermore, the effect of dbcAMP on c-kit expression is reversible. In differentiated cells treated with RA, c-kit gene expression is induced by agents such as forskolin or theophylline, which are known to elevate cellular cAMP level. These results indicate that the expression of the c-kit gene is regulated by the level of intracellular cAMP in differentiated F9 cells induced by RA.

Animals↗

PubMed1992

Evaluation of a cholinomimetic drug, 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta [b] quinoline (NIK-247), as an enhancer of endogenous efflux of acetylcholine from brain slices.

Basal and high K(+)-stimulated efflux of endogenous ACh from slices of brain was measured to evaluate the cholinomimetic effect of 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b] quinoline monohydrate HCl (NIK-247) on the central nervous system. The drug NIK-247 dose-dependently accelerated the efflux of ACh from slices of striatum. The maximum increase produced by 1.0 x 10(-4) M of NIK-247 was 329% in basal and 1332% in 30 mM K(+)-stimulated efflux. This drug was nearly twice as potent as THA (9-amino-1,2,3,4-tetrahydroacridine HCl) but had the same potency as physostigmine, in enhancing basal efflux, although there was no significant difference between the efficacy of these drugs in enhancing the K(+)-stimulated efflux. Both basal and 50 mM K(+)-stimulated efflux of ACh were increased by NIK-247, not only from the striatum but also from slices of frontal cortex and hippocampus. The activity was more effective in the striatum than in other tissues, and more effective on K(+)-stimulated than on basal efflux, regardless of the region of the brain. These effects of NIK-247 may be a result mainly of its inhibition of cholinesterase and its other biological characteristics, such as K+ channel blockade, capable of modulating release of ACh, may not be of major importance.

Acetylcholine↗

PubMed1992

c-myc and p53 gene expression in the differentiation of temperature-sensitive mutants of teratocarcinoma F9 cells.

We have previously reported the isolation of several temperature-sensitive (ts) mutants of F9 cells. Further investigations showed that some mutants were induced to differentiate at non-permissive temperature of cell growth, accompanied by changes in the expression of various genes, whereas others were not. During the differentiation induced by shifting up to the non-permissive temperature, a rapid and transient decrease in both c-myc and p53 mRNA levels and rapid induction of c-jun mRNA were observed. These changes were specific in differentiation-inducible mutants and were not observed in a non-inducible mutant. In both types of mutants, the level of c-myc mRNA decreased in association with growth retardation at the non-permissive temperature. The p53 mRNA, however, showed specific increase in the differentiation-inducible ts mutants. These observations suggest distinct roles for p53 and c-myc from proliferation to differentiation in teratocarcinoma stem cells.

Animals↗