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Biomedical subjects

Y Miyake

Publications and source records attributed to Y Miyake.

At least 469 records · Page 26Linked to original sources
PubMed1988

Reactivities of human urinary prokallikrein and kallikrein toward rabbit antibodies with special reference to enzyme immunoassay.

Human urinary prokallikrein and kallikrein have been analyzed by means of solid phase enzyme immunoassay (EIA) using rabbit antibodies. The anti-kallikrein antibody-immobilized EIA detected both kallikrein and prokallikrein. However, only kallikrein was detectable at concentrations below 20 micrograms/1. The anti-prokallikrein antibody-immobilized EIA detected both kallikrein and prokallikrein, but the binding maximum for kallikrein was about one-third less than that for prokallikrein. Similar difference in reactivity of kallikrein and prokallikrein toward each antibody was observed with immunoaffinity column chromatography and single radial immunodiffusion. The results show that immunochemical properties of human urinary prokallikrein and kallikrein differ distinctly, and conflicting results on detectability of kallikrein and prokallikrein in human urine with EIA or radioimmunoassay using the anti-kallikrein antibody was due to the difference in reactivity of the two forms of kallikrein toward the immobilized antibody.

Animals↗
PubMed1988

Polymorphic differences in alpha- and beta-form crystals of 2R, 4S, 6-fluoro-2-methyl-spiro[chroman-4,4'-imidazoline]-2',5-dione (M79175) as determined by X-ray diffraction, infrared spectroscopy, and differential scanning calorimetry.

Polymorphic differences in alpha- and beta-form crystals of 2R, 4S, 6-fluoro-2-methyl-spiro[chroman-4,4'-imidazoline]-2',5-dione (M79175; 1) were studied by X-ray diffractometry, infrared spectroscopy, and differential scanning calorimetry. X-ray powder diffraction indicated the longest spacing of the unit cells to be 14.9 and 12.4 A for the alpha- and beta-form crystals, respectively. The infrared spectra showed the absorption band assigned to NH streching vibration for the alpha-form crystals to be centered at 3250 cm-1 and that for the beta-form crystals to split into two peaks, at 3150 and 3425 cm-1. The enthalpies of fusion were 26.3 kJ/mol at 517.5 K and 31.3 kJ/mol at 501.0 K, respectively. Transformation from the beta- to alpha-form was observed at various heating rates, which were enhanced by the presence of a small amount of alpha-form crystals previously added to the beta-form. The former appeared to serve as a source of nuclei for the growth of both forms. These results confirm that the alpha-form crystal is more stable than the beta-form.

Calorimetry, Differential Scanning↗
PubMed1988

Mutations of the low density lipoprotein receptor in Japanese kindreds with familial hypercholesterolemia.

Mutations of the low density lipoprotein (LDL) receptor in 16 Japanese kindreds with homozygous familial hypercholesterolemia (FH) were studied using an anti-LDL receptor antibody. The LDL receptor mutations in Japanese FH were heterogeneous and included defects in synthesis, post-translational processing, ligand-binding activity, and internalization of the LDL receptor. Of the 16 kindreds, 10 were receptor-negative and 5, receptor-defective types and 1 was an internalization-defective type with respect to LDL binding. The receptor-negative group was further subdivided into four groups: those with cells producing (i) no immunodetectable receptor (five kindreds); (ii) 160-kd mature receptors, which were quite scarce (two kindreds); (iii) receptors that could not be processed to the mature receptor properly (two kindreds); and (iv) receptors with an apparent molecular weight smaller than normal (one kindred). The last kindred synthesized an about 155-kd mature receptor that was rapidly degraded. This finding is compatible with the low concentration of the cell surface LDL receptors and decreased binding activity for LDL in the cells of this kindred. The receptor-defective group, which could produce a residual amount of functional receptors, exhibited a lower tendency to coronary artery disease than the receptor-negative group.

Homozygote↗
PubMed1988

Secondary release of thromboxane A2 in aerosol leukotriene C4-induced bronchoconstriction in guinea pigs.

Effect of a thromboxane synthetase inhibitor (OKY-046) on bronchoconstriction induced by aerosol leukotriene C4 and histamine was studied in anesthetized, artificially ventilated guinea pigs in order to examine whether secondary release of thromboxane A2 is produced by aerosol leukotriene C4 or not. 0.01-1.0 micrograms/ml of leukotriene C4 and 12.5-400 micrograms/ml of histamine inhaled from ultrasonic nebulizer developed for small animals caused dose-dependent increase of pressure at airway opening (Pao) which is considered to be an index representing bronchial response. Pretreatment of the animals with intravenous OKY-046 (100mg/kg) significantly reduced the airway responses produced by inhalation of 0.1, 0.33 and 1.0 micrograms/ml of leukotriene C4, while the pretreatment did not affect the histamine dose-response curve. Based on these findings and previous reports (6,7), it is suggested that aerosol leukotriene C4 activates arachidonate cyclooxygenase pathway including thromboxane A2 synthesis and the released cyclooxygenase products have bronchodilating effect as a whole.

Aerosols↗
PubMed1988

Primary structure of human urinary prokallikrein.

The complete amino acid sequence of human urinary prokallikrein has been determined by amino acid analysis and sequence determination of peptide fragments obtained from chemical and enzymological cleavages of kallikrein and by comparison of the N-terminal sequence of prokallikrein with that of kallikrein, the active form. Prokallikrein was a single chain polypeptide which comprised 238 amino acid residues of kallikrein and 7 amino acid residues of the propeptide. The sequence, Asn-X-Thr(Ser), which is a common glycosylation site was found at positions 78-80, 84-86, and 141-143. Two trypsin-susceptible sites were identified. One is the Arg(-1)-Ile(1) bond and the other is the Arg (87)-Gln(88) bond. The sequence of human urinary kallikrein was identical with that of human pancreatic and kidney kallikreins (Fukushima, D. et al. (1985) Biochemistry 24, 8037-8043; Baker, A.R. & Shine, J. (1985) DNA 4, 445-459), which were predicted from the nucleotide sequences of cDNAs. The primary structure of human urinary kallikrein is homologous to those of the other animal kallikreins and kallikrein-related proteins. Key amino acid residues, His(41), Asp(96), and Ser(190), required for catalytic activity and Asp (184) required for kallikrein-type specificity are completely conserved. The results show that human urinary prokallikrein and kallikrein are of tissue type and they are excreted in urine without any modification.

Amino Acid Sequence↗
PubMed1988

Complex formation between anionic semiquinoid form of a flavoenzyme D-amino acid oxidase and ligands. Stabilizing mechanism of anionic semiquinoid flavoenzyme.

Picolinate binds to the anionic semiquinoid form of D-amino acid oxidase (DAO), and the complex formed has a broad absorption band in the long-wavelength region extending beyond 800 nm, which is reminiscent of a charge transfer interaction. The binding has a stoichiometry of 1:1 with respect to the enzyme. The dissociation constant at 25 degrees C was 30 microM at pH 7.0. The pH dependence (pH 7.0-8.3) of the dissociation constant indicates that one proton is associated with the complex formation, and suggests that picolinate able to bind to the anionic semiquinoid enzyme is in the cationic form protonated at the nitrogen atom. By adding dithionite to the oxidized DAO solution containing pyruvate and various amines, a similar anionic semiquinoid DAO complex having a broad long-wavelength absorption band, appeared. Resonance Raman spectra with excitation at 623.8 nm of the anionic semiquinoid DAO complex formed in the presence of pyruvate and methylamine indicate that the complex consists of the anionic semiquinoid DAO and N-methyl-alpha-iminopropionate produced from pyruvate and methylamine, and that the imino group must be protonated. This supports the proposal that the presence of a positively charged group in the vicinity of flavin is required for the stabilization of the anionic semiquinoid flavin. The results also suggest that the broad absorption band is derived from the charge transfer interaction between the anionic semiquinoid flavin and the imino acid, in which the flavin C(4a)-N(5) locus and the locus containing (Formula: see text) of the amino acid are important for the interaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical Phenomena↗
PubMed1988

Production of parathyroid hormone-related protein in adult T-cell leukemia cells.

Human parathyroid hormone-related protein (PTHrP) mRNA was detected in peripheral leukemic cells obtained from adult T-cell leukemia (ATL) patients as well as in cultured human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines. In contrast, PTHrP mRNA was not detected in other types of leukemic cells. Using radioimmunoassay, immunoreactive PTHrP was also detected in the spent media of HTLV-I-infected T-cell lines. These results suggest that PTHrP plays an important role in developing the hypercalcemia frequently observed in ATL patients.

HTLV-I Infections↗
PubMed1988

Tissue oxygen tension in the stria vascularis.

Tissue oxygen tension in the stria vascularis was successfully measured in cats using the polarographic technique. A correlation study using the differential coefficient between oxygen tension in the stria vascularis and systemic blood pressure proved that vascular autoregulation is present in the mean systemic blood pressure range between 40 and 80 mmHg. The anatomical findings and the response patterns to different gas inhalations indicated that the type of vascular regulation present is more closely related to chemical control than to auto-regulation.

Animals↗
PubMed1988

Intestinal absorption of riboflavin, studied by an in situ circulation system using radioactive analogues.

The intestinal absorption of riboflavin was studied using radioactive riboflavin and its analogues 8-demethylriboflavin, 3-methylriboflavin, 5'-deoxyriboflavin, 2'-deoxyriboflavin, 7,8-dimethyl-10-hydroxyethylisoalloxazine, lumiflavin, lumichrome, and riboflavin-5'-monosulfate, which were synthesized with high specific radioactivity. A specific absorption of riboflavin at dietary concentrations was confirmed using an in situ circulation system. The relation between the chemical structure of flavins and the absorption mechanism was studied using this system. The 8-demethylriboflavin, an analogue modified at benzene moiety of the isoalloxazine ring, was absorbed in a similar way to riboflavin, by dual kinetics: by a process specific for riboflavin at dietary concentrations and by simple diffusion (nonspecific absorption) predominating at higher concentrations (over 100 microM). However, 3-methylriboflavin and analogues modified at the ribityl group, including 5'-deoxyriboflavin, were absorbed only via simple diffusion even at dietary concentrations. Many flavins examined, except for 3-isobutylriboflavin, 3-carboxymethylriboflavin, lumichrome, and riboflavin-5'-monosulfate, interfered with the specific absorption of riboflavin. It was concluded from these results that one of the specific absorption processes for riboflavin is a phosphorylation-dephosphorylation process. Four water-soluble vitamins did not interfere with the specific absorption of riboflavin, indicating that these vitamins do not share a common specific absorption pathway with riboflavin.

Animals↗
PubMed1988

Characterization of hog kidney renin-binding protein: interconversion between monomeric and dimeric forms.

A radioimmunoassay for hog kidney renin-binding protein (RnBP) was developed. Using this assay method, we investigated the properties of hog kidney RnBP. The lower limit of detection was 24 fmol RnBP. The molecular weight of RnBP in hog kidney extract, as well as the purified RnBP, was estimated to be 65,000 by gel filtration on Ultrogel AcA 44. When the purified RnBP was treated with N-ethylmaleimide (NEM) or 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), the molecular weight was reduced to 38,000. DTNB-treated RnBP was reconverted to the 65,000-dalton species with dithiothreitol. Cross-linked high molecular weight species of RnBP were produced by the reaction of native RnBP with dimethyl suberimidate, but formation of such species was much less with NEM-treated RnBP. These results suggest that the native RnBP exists as a dimeric form and dissociates to a monomeric form by sulfhydryl-alkylating or -oxidizing reagent. It was shown from analysis of amino acid composition of S-carboxymethylated RnBP and titration of sulfhydryl groups of native and NEM-treated RnBP with DTNB that native RnBP contained twelve cysteine residues and that three cysteine residues were alkylated by NEM under the conditions employed.

Alkylation↗
PubMed1988

[Changes in CT findings in patients with liver metastases of breast cancer during effective intra-arterial infusion].

A study was done of the changes occurring in the CT findings of 12 cases in which liver metastases were found after radical mastectomy for breast cancer, as a result of intermittent low-dose hepatic arterial infusion chemotherapy using a reservoir, achieving PR. In four cases (33.3%) only shrinkage of the metastatic lesions was seen; in 3 others (25.0%), this was accompanied by irregularities in the margins of the liver surface; in the other 5 (41.7%), a high proportion of total, widespread compensatory deformity of the liver was observed. A tendency was noted for these changes to be more pronounced in cases in which the metastatic lesions occupied a large proportion of the liver. Hepatic degeneration appeared with a high frequency in cases where liver metastasis followed breast cancer, and it is considered that considerable care is necessary in evaluating the efficacy of treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Enhancement by recombinant interferon-gamma of spontaneous tumor cytostasis by human neutrophils.

Human peripheral neutrophils treated with recombinant human interferon-gamma (IFN) inhibited tritiated thymidine (3H-TdR) uptake by various tumor cells. The concentration-response curve of IFN required for induction of cytostatic activity of neutrophils showed two peaks. Short time incubation of neutrophils with IFN at 4 degrees C was sufficient for inducing neutrophil cytostasis. When neutrophils pretreated with IFN for 5 min at 4 degrees C were further treated with trypsin, cytostasis by the treated neutrophils was decreased depending on the concentration of trypsin, whereas cytostasis by neutrophils pretreated with IFN for 180 min at 37 degrees C was not inhibited by trypsin treatment. Cytostatic activity induced by IFN was inhibited by pretreatment of IFN with anti-IFN-monoclonal antibody.

Animals↗