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Biomedical subjects

J Ishida

Publications and source records attributed to J Ishida.

At least 73 records · Page 4Linked to original sources
PubMed1989

High-performance liquid chromatography of arachidonic acid metabolites and its application to the determination of leukotriene B4 in stimulated leukocytes.

A highly sensitive high-performance liquid chromatography with fluorescence detection for the determination of arachidonic acid metabolites is described. The metabolites are converted into corresponding fluorescent derivatives by reaction with 3-bromomethyl-6,7-methylenedioxy-1-methyl-2(1H)-quinoxalinone in the presence of potassium hydrogen carbonate and 18-crown-6 in acetonitrile. The derivatives are separated on a reversed-phase column (Inertsil ODS) with aqueous acetonitrile and detected fluorimetrically. The detection limits are 5-15 fmol at a signal-to-noise ratio of 3 in a 10-microliter injection volume. The method is applied to the determination of leukotriene B4 produced in stimulated leukocytes.

Arachidonic Acids↗
PubMed1989

Determination of 21-hydroxycorticosteroids in human urine by high-performance liquid chromatography with fluorescence detection.

A simple and sensitive high-performance liquid chromatographic method with fluorescence detection for the determination of nineteen 21-hydroxycorticosteroids is described. The corticosteroids are oxidized by cupric acetate to form the corresponding glyoxal derivatives. The derivatives are converted into fluorescent quinoxalines by reaction with 1,2-diamino-4,5-methylenedioxybenzene, a fluorogenic reagent for alpha-dicarbonyl compounds. The quinoxalines are separated within 70 min on a reversed-phase column (TSK gel ODS-120T) by stepwise elution with mixtures of methanol, acetonitrile, and 1.0 M ammonium acetate. The detection limits are 0.14-29.4 pmol at a signal-to-noise ratio of 3 in a 50-microliter injection volume. This sensitivity permits precise determination of hydrocortisone, cortisone, corticosterone, and their tetrahydro derivatives in 500 microliters of normal human urine.

Chromatography, High Pressure Liquid↗
PubMed1989

[The accuracy of CT and tumor markers in the detection of a recurrent ovarian carcinoma].

Twenty-three patients previously diagnosed as having ovarian cancer were examined with both serum tumor markers (CA 125, CA 19-9, TPA, IAP, AFP) and a pelvic CT scan. The tumor markers predict the clinical outcome more accurately than the CT scan. Further, the tumor markers showed a clear correlation with the clinical course. But in one case, however, the tumor markers were seen to reduce below the normal level from chemotherapy, while the CT scan showed a tumor mass. Thus, both, a CT scan and tumor marker assays are felt to be indispensable for detecting the recurrence of an ovarian cancer.

Adenocarcinoma, Mucinous↗
PubMed1989

[CT image of primary ovarian cancer seeding to the peritoneal cavity].

Early diagnosis of primary ovarian cancer is difficult, because of a few symptoms and clinical signs, this cancer has many pathological findings and CT images. Therefore, initial CT Scan documents often the seeding to peritoneal cavity. We evaluated the seeding pathway to peritoneal cavity for 59 primary ovarian cancer by CT, especially ascites, omental metastasis, peritoneal metastasis and scalloping.

Adolescent↗
PubMed1989

[Clinical usefulness of three-dimensional brain imaging with N-isopropyl-p-[123I]iodoamphetamine (IMP)].

Three-dimensional reconstruction from N-isopropyl-p-[123I]iodoamphetamine (IMP) tomography has been applied clinically to the detection of perfusion defects in 22 cases (15 cerebrovascular diseases and 7 normal controls confirmed by CT and MRI), with data being analyzed in terms of receiver operating characteristic curves (ROC). The results showed that three-dimensional (3-D) image could make better diagnostic capability especially in inexperienced examiner and that it was useful decreasing of difference of diagnostic capability. 3-D image could be taken within 1 minute and 15 seconds. We concluded that the three-dimensional brain imaging with IMP using this system was clinically useful because examiner could easily diagnose perfusion defects.

Aged↗
PubMed1988

Determination of oestrogens in pregnancy urine by high-performance liquid chromatography with fluorescence detection.

A simple and sensitive high-performance liquid chromatographic method is described for the determination of three oestrogens (oestriol, oestrone and oestradiol) in pregnancy urine. Free oestrogens are extracted with chloroform from the urine sample. The phenolic group of each oestrogen in chloroform is formylated in the presence of an alkaline aqueous solution, and the resulting aldehyde is converted into a fluorescent derivative by reaction with 1,2-diamino-4,5-dimethoxybenzene. In order to determine free and conjugated oestrogens, conjugated oestrogens are hydrolysed by heating in hydrochloric acid before the extraction and then treated in the same way as free oestrogens. The fluorescent derivatives are separated on a reversed-phase column, TSKgel ODS-120T, with stepwise gradient elution using an aqueous methanol-containing phosphate buffer (pH 2.2). The lower limit of detection for each oestrogen is ca. 200 fmol per 100-microliters injection volume.

Chromatography, High Pressure Liquid↗
PubMed1988

High-performance liquid chromatographic determination of leucine-enkephalin-like peptide in rat brain by pre-column fluorescence derivatization involving formylation followed by reaction with 1,2-diamino-4,5-dimethoxybenzene.

Fluorimetrically reactive leucine-enkephalin, one of the opioid peptides in rat brain tissues such as the striatum, cortex and hypothalamus, was assayed by reversed-phase high-performance liquid chromatography with fluorescence detection based on pre-column derivatization of the tyrosyl residue. The tyrosine-containing peptides extracted from the tissue were first formylated with chloroform in an alkaline medium, and the resulting aldehydes were then converted into highly fluorescent derivatives by reaction with 1,2-diamino-4,5-dimethoxybenzene. The derivative of leucine-enkephalin-like peptide in tissue was separated from various other fluorescent compounds on a reversed-phase column (TSK gel ODS-120T) by isocratic elution and detected by fluorimetry. The concentrations of the leucine-enkephalin-like peptide in the tissues were 20-245 pmol/g. The method is sensitive enough to permit the quantitative determination of the endogenous peptide at concentrations as low as 5.6 pmol/g in brain tissues.

Animals↗
PubMed1987

Genistein, a specific inhibitor of tyrosine-specific protein kinases.

Tyrosine-specific protein kinase activity of the epidermal growth factor (EGF) receptor, pp60v-src and pp110gag-fes was inhibited in vitro by an isoflavone genistein. The inhibition was competitive with respect to ATP and noncompetitive to a phosphate acceptor, histone H2B. By contrast, genistein scarcely inhibited the enzyme activities of serine- and threonine-specific protein kinases such as cAMP-dependent protein kinase, phosphorylase kinase, and the Ca2+/phospholipid-dependent enzyme protein kinase C. When the effect of genistein on the phosphorylation of the EGF receptor was examined in cultured A431 cells, EGF-stimulated serine, threonine, and tyrosine phosphorylation was decreased. Phosphoamino acid analysis of total cell proteins revealed that genistein inhibited the EGF-stimulated increase in phosphotyrosine level in A431 cells.

Cell Line↗
PubMed1986

Purified protein kinase C phosphorylates microtubule-associated protein 2.

We have investigated actions of purified protein kinase C on microtubule- and microfilament-related proteins. Among the cytoskeletal proteins examined, microtubule-associated protein 2 (MAP2) was found to serve as a good substrate. Other cytoskeletal proteins, tubulin, fodrin, cofilin, tropomyosin, and 53,000-Da protein, were very poorly phosphorylated. The amino acid residues of MAP2 that were phosphorylated by the protein kinase C were almost exclusively serine. The peptide mapping analysis indicated that protein kinase C and cAMP-dependent protein kinase phosphorylate MAP2 differently. The ability of MAP2 to interact with actin was markedly reduced by this protein kinase C-mediated phosphorylation. These data raise the possibility that phosphorylation of MAP2 by activated protein kinase C may be involved in cell-surface signal transduction.

Actins↗
PubMed1986

High-performance liquid chromatography of tyrosine-containing peptides by pre-column derivatization involving formylation followed by fluorescence reaction with 1,2-diamino-4,5-dimethoxybenzene.

A pre-column fluorescence derivatization method is described for the high-performance liquid chromatographic determination of tyrosine-containing peptides. A tyrosyl residue in the peptide is first formylated in an alkaline medium in the presence of chloroform, and the resulting aldehyde is then converted into a fluorescent derivative by reaction with 1,2-diamino-4,5-dimethoxybenzene. The derivative is separated on a reversed-phase column (LiChrosorb RP-18) by isocratic elution with an aqueous acetonitrile-containing potassium chloride-hydrochloric acid buffer (pH 2.2) and sodium 1-hexanesulphonate. The method is selective and fairly sensitive; the lower limits of detection for the tyrosine-containing peptides tested are in the range 3.4-26.2 pmol in a 100-microliter injection volume.

Amino Acid Sequence↗
PubMed1985

High-performance liquid chromatographic method for monitoring leupeptin in mouse serum and muscle by pre-column fluorescence derivatization with benzoin.

A high-performance liquid chromatographic method is described for the determination of leupeptin, a possible therapeutic drug for muscular dystrophy, in mouse serum and muscle. Leupeptin is reduced with sodium borohydride to leupeptinol, and then converted to a fluorescent derivative with benzoin. The derivative is separated on a reversed-phase column (LiChrosorb RP-18) with isocratic elution and determined with fluorescence detection. The detection limits of leupeptin in serum and muscle are 250 pmol/ml (107 ng/ml) and 500 pmol/g (214 ng/g), respectively, corresponding to approximately 150 fmol each in a 100-microliters injection volume. This method is simple and sensitive enough to permit the quantification of leupeptin in biological samples from mice dosed with leupeptin.

Animals↗
PubMed1985

Determination of p-hydroxybestatin in human serum by high-performance liquid chromatography using fluorescence detection.

A high-performance liquid chromatographic method is described for the fluorimetric determination of p-hydroxybestatin (an active metabolite of bestatin) in human serum. p-Hydroxybestatin is formylated in an alkaline medium in the presence of chloroform, and converted to a fluorescent derivative with 1,2-diamino-4,5-dimethoxybenzene. This derivative is then separated on a reversed-phase column (TSK gel ODS-120T) with isocratic elution. The detection limit of p-hydroxybestatin in serum is 15 ng (46 pmol) per ml serum (115 pg in a 100-microliters injection volume). This method is simple and sensitive enough to determine p-hydroxybestatin in serum (200 microliters) from muscular dystrophic patients and from healthy subjects dosed with bestatin.

Chemical Phenomena↗
PubMed1984

Determination of bestatin in serum by high-performance liquid chromatography with fluorescence detection.

A simple method for the determination of bestatin and its major metabolite in man, p-hydroxybestatin, in human serum was investigated; the method employs high-performance liquid chromatography with fluorescence detection. Bestatin and p-hydroxybestatin are oxidized to phenylacetaldehyde and p-hydroxyphenylacetaldehyde, respectively, with periodate, which are then converted into fluorescent compounds with 4,5-dimethoxy-1,2-diaminobenzene. The compounds are separated by reversed-phase chromatography on LiChrosorb RP-18. The detection limits of bestatin and p-hydroxybestatin are 0.2 and 0.4 microgram/ml serum, respectively. This method permits the precise determination of bestatin in serum (20 microliter) from patients administered bestatin. p-Hydroxybestatin in serum can not be measured by this method because of its low concentration (less than the detection limit).

Chromatography, High Pressure Liquid↗
PubMed1983

Histidinomycin, a new antifungal antibiotic.

A new antifungal antibiotic named histidinomycin was isolated from the broth filtrate of a streptomycete, tentatively designated as isolate H 878-MY 1. Histidinomycin was purified as the monohydrochloride and the molecular formula was proposed to be C22H30N8O11.HCl. The antibiotic gave histidine by acid hydrolysis. Histidinomycin showed rather narrow antimicrobial spectrum for only few genera of phytophathogenic fungi.

Anti-Bacterial Agents↗