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Biomedical subjects

M Shinoda

Publications and source records attributed to M Shinoda.

At least 217 records · Page 12Linked to original sources
PubMed1987

Circadian variability of blood pressure and heart rate in newborns and cardiovascular chronorisk.

At present, neonates are being given screening tests for relatively rare diseases, such as phenylketonuria. The time has come to give emphasis to assessing the risk for major handicapping diseases, such as coronary heart disease, stroke, and certain diseases of the kidney. Modern technology for blood pressure and heart rate monitoring and data analysis provides noninvasive means to determine when preventive measures are indicated.

Blood Pressure↗
PubMed1986

Amino terminal sequence analysis of human placenta aromatase.

The amino acid composition and the amino-terminal amino acid sequence from position 1 to 21 of human placenta aromatase were determined. In addition, a cysteine containing peptide with a sequence homologous to those of peptides containing the cysteine residue which was suggested to provide the proximal thiolate ligand to the heme in other cytochrome p-450 isozymes, was identified. The results indicate that aromatase is a cytochrome p-450 protein, probably derived from a new cytochrome p-450 family.

Amino Acid Sequence↗
PubMed1986

Purification to homogeneity of aromatase from human placenta.

Aromatase cytochrome P-450 has been purified from human placenta to homogeneity, as demonstrated by electrophoresis on polyacrylamide gels with SDS, and by double diffusion against an antibody raised in rabbits. The enzyme converts androstenedione to estrone (Vmax 13.3 n moles/min/n mole P-450; Km 30 microM) and testosterone to estradiol. Aromatase activity requires P-450, P-450 reductase and NADPH. Enzyme activity is inhibited by anti-aromatase antibodies and by 4-hydroxyandrostenedione. The enzyme shows a molecular weight of 55,000, is extremely unstable and spontaneously forms P-420 with a half-life of 2.5 days.

Aromatase↗
PubMed1986

Hymenolepis nana: passive transfer of mouse immunity by T-cell subset of phenotype Lyt-1.

Mesenteric lymph node cells obtained from donor mice (BALB/c strain) actively immunized by oral inoculation with Hymenolepis nana eggs were syngeneically transferred by intravenous injection into athymic nude mice previously uninfected. The adoptively immunized recipients were then challenged with 1000 H. nana eggs 2 days after cell transfer. The degree of immunity transferred was assessed by examining cysticercoids developed in the intestinal villi of the recipients on Day 4 of challenge infection. The criterion for success in cell transfer of immunity was the complete rejection of cysticercoids as was generally expected in mice infected previously. The transfer of 1.5 X 10(8) immune mesenteric lymph node cells obtained from donors immunized 4 days before cell collection resulted invariably in the complete rejection of cysticercoids, though not less than this cell dosage. The immunity was passively transferable to recipients by T cells, especially by T-cell subset of phenotype Lyt-1 but not those of phenotype Lyt-2.3 and Lyt-1.2.3. However, 1.5 X 10(8) immune mesenteric lymph node cells obtained from donors immunized 21 days before cell transfer and 1.5 X 10(8) immune spleen cells obtained from donors immunized 4 days before cell transfer had little or no effect on the rejection of cysticercoids.

Animals↗
PubMed1985

Cytochrome b5 promotes the synthesis of delta 16-C19 steroids by homogeneous cytochrome P-450 C21 side-chain cleavage from pig testis.

Conversion of progesterone to 17 alpha-hydroxyprogesterone plus androstenedione (17 alpha-hydroxylation) and to androstadienone (delta 16 synthetase activity) by microsomes from neonatal pig testis, were both inhibited by antibodies raised against homogeneous cytochrome P-450 C21 side-chain cleavage. Inhibition of the two activities showed the same relationship to the concentration of antibody added. Analogous results were obtained with pregnenolone as substrate. In a reconstituted enzyme system consisting of the homogeneous cytochrome P-450 C21 side-chain cleavage enzyme, P-450 reductase and NADPH, addition of cytochrome b5 resulted in the synthesis of the corresponding delta 16-C19-steroid from progesterone (androstadienone) and pregnenolone (androstadienol). The effect of cytochrome b5 was concentration-dependent and prevented by anti-cytochrome b5. It is concluded that the cytochrome P-450 C21 side-chain cleavage enzyme from pig testicular microsomes is also capable of synthesizing delta 16-C19-steroids and is, therefore, likely to be responsible for the large amounts of the pherormone androstadienone produced by male pigs.

Aldehyde-Lyases↗
PubMed1985

A case of childhood multiple sclerosis with peripheral neuropathy.

A twelve-year-old girl with multiple sclerosis and peripheral neuropathy is reported. When nine years old, she was diagnosed as having Devic disease (optic atrophy and transverse myelitis). During the three years after onset of her illness, she suffered from three relapses and remissions of her multiple sclerosis. On the third occasion, neurological examination revealed signs of cerebellar dysfunction including ataxic gait, nystagmus and dysmetria, and absence of all tendon reflexes with muscle weakness especially on the left side. Markedly slowed conduction velocity in her ulnar nerve especially on the left and elevated CSF protein were noted. Biopsied sural nerve showed decreased density of myelinated fibers and a selective loss of large diameter fibers. Electron microscopy disclosed onion-bulb formation, myelin debris within Schwann cell cytoplasm and demyelinated axons. These findings showed demyelination and remyelination of the peripheral nervous system in this patient with multiple sclerosis. We discuss the relation of multiple sclerosis and peripheral neuropathy.

Biopsy↗
PubMed1985

Evidence for involvement of cytochrome P-450-linked oxygenase system in the conversion of C21-steroids to delta 16-C19-steroids catalyzed by pig testicular microsomes.

Formation of androstadienone or androstadienol, a delta 16-C19-steroid, from progesterone or pregnenolone is catalyzed by the so-called delta 16-C19-steroid synthesizing enzyme in the pig testicular microsomes. The enzyme activity was also present in the testicular microsomes prepared from neonatal pig. The enzyme activity was considerably inhibited by CO, and such cytochrome P-450 inhibitors as SU 8000, SU 10603, and metyrapone. delta 16-C19-Steroid synthesizing enzyme activity was extracted from the testicular microsomes by sodium cholate in potassium phosphate buffer, pH 7.4, containing EDTA and dithiothreitol, and the solubilized enzyme activity was partially purified by DEAE-cellulose column chromatography. It was shown by reconstitution of the enzyme activity that delta 16-C19-steroid synthesizing enzyme is a cytochrome P-450-linked oxygenase system dependent on cytochrome P-450-reductase and cytochrome b5. In particular, cytochrome b5 was an essential component for the activity of delta 16-C19-steroid synthesizing enzyme.

Animals↗