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Biomedical subjects

T Aoyagi

Publications and source records attributed to T Aoyagi.

At least 307 records · Page 17Linked to original sources
PubMed1986

A novel synthetic vitamin-A-like compound (a polyprenoic acid derivative: E-5166) inhibits UVB-stimulated epidermal ornithine decarboxylase activity.

Irradiation of skin with ultraviolet B (UVB) stimulates epidermal activity of ornithine decarboxylase (ODC), a rate limiting polyamine biosynthesing enzyme. The maximum stimulation of ODC activity by UVB was found at 24 after irradiation. Systemic administration of a polyprenoic acid derivative (E-5166) significantly inhibited the UVB-stimulated ODC activity in a dose-dependent manner. The inhibitory effect of E-5166 on the UVB-stimulated ODC activity was found to begin at 5 mg/kg body weight. These results indicate that because it inhibits ODC activity E-5166 can be utilized for the treatment of hyperproliferative skin diseases.

Animals↗
PubMed1986

Ionophore A23187 stimulates arachidonic acid release and cyclic GMP accumulation in pig epidermis.

We studied the effect of Ionophore A23187 (A23187) on phospholipid degradation and the accumulation of cyclic GMP in pig epidermis. A23187 stimulated the release of AA, probably partially through the activation of phospholipase A2. A23187 also stimulated the accumulation of epidermal cyclic GMP, but the activity of cyclic GMP-dependent phosphodiesterases was not altered. Mepacrine, an inhibitor of phospholipase A2, inhibited the A23187-stimulated accumulation of cyclic GMP. The results suggest that A23187 stimulates the accumulation of epidermal cyclic GMP by a calcium-dependent process which also requires products of phospholipid degradation.

Animals↗
PubMed1986

Milk of calcium renal stone and renal pelvic cancer associated with hydronephrosis.

A 56-year-old male was admitted to a hospital because of gastric ulcer in 1967, and by chance he was diagnosed right milk of calcium renal stone associated with hydronephrotic kidney by plain abdominal X-ray film. In 1979, he was admitted to our hospital complaining of hematuria, and died from renal pelvic cancer on the 49th hospital day. Milk of calcium renal stone associated with hydronephrotic kidney is rare, with only 13 cases were reported previously. This is the first report, a case of milk of calcium renal stone associated with hydronephrosis died from renal pelvic cancer.

Calcium Carbonate↗
PubMed1986

Plipastatins: new inhibitors of phospholipase A2, produced by Bacillus cereus BMG302-fF67. I. Taxonomy, production, isolation and preliminary characterization.

Plipastatins have been isolated as part of a program designed to find inhibitors of porcine pancreatic phospholipase A2. They were purified from fermentation broth of Bacillus cereus BMG302-fF67 and finally separated into four fractions by reverse phase HPLC. The respective fractions were designated as plipastatins A1, A2, B1 and B2. Plipastatins also inhibited phospholipases C and D.

Animals↗
PubMed1986

Plipastatins: new inhibitors of phospholipase A2, produced by Bacillus cereus BMG302-fF67. II. Structure of fatty acid residue and amino acid sequence.

Plipastatins, new inhibitors of phospholipase A2, were produced by a strain classified as Bacillus cereus BMG302-fF67. The plipastatins are a family of acylated decapeptides which differ from each other by amino acid composition and the nature of the fatty acid side chain. The fatty acids have been shown to be 3(R)-hydroxyhexadecanoic acid (n-C16h3) and 14(S)-methyl-3(R)-hydroxyhexadecanoic acid (a-C16h3) by mass, NMR and optical rotation. Amino acid sequence analysis by secondary ion mass spectrometry and additional physico-chemical evidence indicate that the structures of plipastatinic acids, the lactone-opened peptides are as follows: beta-Hydroxy fatty acid----L-Glu----D-Orn----L-Tyr----D-allo-Thr----L-Glu----D-Ala(Val)---- L-Pro----L-Gln----D-Tyr----L-Ile X OH.

Amino Acid Sequence↗
PubMed1986

Plipastatins: new inhibitors of phospholipase A2, produced by Bacillus cereus BMG302-fF67. III. Structural elucidation of plipastatins.

Plipastatins are new inhibitors of phospholipase A2 produced by Bacillus cereus BMG302-fF67. Structures of the plipastatins have been determined by UV, mass and NMR spectrometries and chemical degradation. The carboxyl group of the C-terminal L-isoleucine of plipastatinic acid has been shown to form a lactone linkage with the hydroxyl group of L-tyrosine. The total structure of plipastatins has thus been established.

Anti-Bacterial Agents↗
PubMed1986

The dissociation between the plasma levels of aminopeptidases A and B in spontaneously hypertensive rats.

We performed a longitudinal study for 20 weeks on spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKR) to determine the relationship between peptide metabolism and the age-dependent increase in blood pressure. In both SHR and WKR, the plasma level of aminopeptidase A (AP-A) clearly showed an age-dependent decrease. The plasma level of aminopeptidase B paralleled that of AP-A in WKR, but such an age-dependency was not observed in SHR, thus showing a dissociation between the two aminopeptidases. With age in both strains, the level of angiotensin-converting enzyme tended to decrease, while that of kallikrein activity tended to increase. In addition to these findings, a multivariate study testing the relationship of blood pressure to these enzyme activities, as well as to plasma levels of angiotensin I and renin activity, suggested abnormalities in the networks of proteolytic enzymes and in the peptide metabolism surrounding the renin-angiotensin system in SHR. These abnormalities may play some important roles in pathophysiological mechanisms of hypertension in SHR.

Aging↗
PubMed1986

Cell-free biosynthesis of arphamenine A.

Arphamenine A was synthesized in a cell-free system obtained from the arphamenine-producing strain, Chromobacterium violaceum BMG361-CF4. L-[14C]-phenylalanine was converted to beta-phenylpyruvic acid by phenylalanine amino-transferase obtained from the 10,000 x g supernatant (S10 fraction). [14C]-Benzylmalic acid was synthesized from beta-phenylpyruvic acid with [14C]-acetyl-CoA in the S10 fraction. [14C]-Benzylsuccinic acid was formed from beta-phenylpyruvic acid with [14C]-acetyl-CoA and ATP in this fraction, as was [14C]-arphamenine A from benzylsuccinic acid and L-[14C]-arginine. Thus, the pathway of arphamenine A biosynthesis was confirmed by the cell-free biosynthesis of this antibiotic.

Acetyl Coenzyme A↗
PubMed1986

Biosynthesis of an unusual amino acyl moiety contained in bestatin.

The biosynthetic pathway of an unusual amino acyl [(2S,3R)-3-amino-2-hydroxy-4-phenylbutanoyl (AHP)] moiety which is contained in bestatin has been studied by testing the incorporation of potential precursors. L-[U-14C]-Phenylalanine, L-[U-14C]leucine, and [U-14C]acetic acid were efficiently incorporated into bestatin, but the radioactivity of L-[1-14C]phenylalanine, [1-14C]glyoxylic acid, and [14C]oxalic acid were not incorporated. Incorporation of acetic acid into 1- and 2-carbon of the AHP moiety was confirmed by incorporation of [13C]acetic acid. Thus, the AHP moiety was shown to be biosynthesized from L-phenylalanine and two carbon atoms of acetic acid, accompanied by decarboxylation of the phenylalanine.

Acetates↗
PubMed1986

Relation of hydrolytic enzymes in spleen to immunological dysregulation in mice.

In order to know the role of hydrolytic enzymes in various immunological disturbances, we compared the enzymatic changes in the spleens of nude mice and NZB/W mice relative to their respective controls. In spite of the different immunological features of these models, multivariate analysis demonstrated that there is some commonness in enzymatic changes between the two models. The enzymes related to such commonness included glycosidases, alkaline phosphatase, fMet-AP, and esterase. These enzymes may play some important roles in immunologic dysregulation , especially in relation to B-cell dominance in these disease models.

Animals↗
PubMed1986

Three modes of age-related changes of hydrolytic enzymes in murine brain.

We followed the time course of the activities of various hydrolytic enzymes in murine brain for 30 months to investigate their roles in the aging process. Although most of the 15 enzymatic activities tested tended to rise with the increase in age, by analyzing them by multivariate analysis their movements could be divided into three types, each having a particular mode of nonlinear regression: exponential, logarithmic, or parabolic. Several enzymatic activities, including those of angiotensin-converting enzyme, esterase, trypsin-like enzyme, post-proline-cleaving enzyme, and Gly-Pro-aminopeptidase, showed rhythmic oscillations with about one cycle per 3 months throughout the period of 30 months. The behavior of these enzymes probably represents some particular aspect of metabolism relatively independent from the aging process. These findings may provide a fundamental clue in association with the process of maturation and aging in the brain.

Aging↗
PubMed1985

Lectin-binding pattern in normal human gastric mucosa. A light and electron microscopic study.

Normal human gastric mucosal cells were examined by light and electron microscopy using lectins as a probe. The ABC method was used with biotinylated lectins for light microscopy and HRP-labeled lectins for electron microscopy. The human gastric mucosal cells revealed specific binding patterns for each lectin by light microscopy. Among the lectins tested, in particular, DBA gave a characteristic pattern. It specifically stained the supranuclear region of surface epithelial cells and the perinuclear region of parietal cells. By electron microscopy, the stacked cisternae and the vesicles of the Golgi apparatus of the surface epithelial cells were positive for the DBA staining. These results show that the DBA-positive supranuclear region observed by light microscopy corresponds to the Golgi apparatus. In the parietal cells, DBA, RCA and ConA bound to the intracellular secretory canaliculi which are invaginations of the cell membrane running around the nucleus in the cytoplasm. Therefore, the tubular perinuclear positive region observed by light microscopy corresponds to the membranes of the intracellular secretory canaliculi. In addition, the ConA reagent stained the endoplasmic reticulum, Golgi apparatus, nuclear envelope, and cell membrane of the parietal cell, which explains the diffuse cytoplasmic staining observed at the light microscopic level with this lectin. Lectins have proved to be very useful for the evaluation of in situ cytochemical aspects of the glycoconjugates characteristic to human gastric mucosal cells.

Gastric Mucosa↗
PubMed1985

Epidermal growth factor stimulates release of arachidonic acid in pig epidermis.

Epidermal growth factor (EGF) at physiologic concentrations (0.001-0.1 microgram/ml) stimulated the release of [14C] arachidonic acid [14C-AA] from pig epidermis. Although EGF stimulated the release of AA in the absence of exogenously added calcium to some extent, the addition of calcium (0.3-1.2 mM) significantly potentiated the release of AA stimulated by EGF. Ionophore A23187, which is known to stimulate phospholipase A2 activity by opening the calcium gates, potentiated the EGF-stimulated release of AA. The stimulatory effect of EGF was partially inhibited by the addition of mepacrine (70% inhibition at 10 microM) and by the pretreatment of hydrocortisone (60% inhibition at 1.0 microM). The loss of 14C-labeled phospholipids in pig epidermis was mainly due to the degradation of 14C-labeled phosphatidylcholine. Present results and recent reports by other workers suggest that EGF stimulates phospholipase A2 activity and result in the increased release of AA.

Animals↗
PubMed1985

Characterization of adenosine deaminase from normal human epidermis and squamous cell carcinoma of the skin.

We compared the characteristics of adenosine deaminases (ADs) (E.C. 3.5.4.4.) in squamous cell carcinoma and normal human epidermis. Increased specific activity (per mg protein) of AD was observed in squamous cell carcinoma compared with that of the normal epidermis. In normal human epidermis most of the AD existed as a large form (Mr 300,000-350,000, type A). Squamous cell carcinoma of the skin was characterized by a high proportion of small-form (Mr 30,000-40,000, type C) AD. The proportion of the small-form enzyme varied from tumor to tumor. Comparison of the large-form AD from squamous cell carcinoma to that from normal epidermis revealed that both enzymes were similar in relative substrate specificity, Km values for adenosine, pH optima, heat stability pattern, isoelectric point, and sensitivity to inhibition by coformycin, a tight binding inhibitor of AD. However, the low molecular weight of AD from squamous cell carcinoma was less heat stable than that from the large-molecular-weight form. Increased AD activity and the high proportion of the small form of AD might be significant features of squamous cell carcinoma of the skin.

Adenosine Deaminase↗
PubMed1985

Epidermal growth factor stimulates tyrosine phosphorylation of pig epidermal fibrous keratin.

Epidermal growth factor (EGF) stimulated phosphorylation of pig epidermal proteins, one of which was pig epidermal keratin. In order to further characterize phosphorylated proteins and specify the EGF-dependent protein phosphorylation, we attempted to identify phosphorylated keratin proteins and to analyze phosphorylated phosphoamino acids of keratin proteins stimulated by EGF. Four major polypeptide bands of pig epidermal keratin were immunoprecipitated by antihuman callus keratin antibody which reacted with fine networks of fibrous keratin of pig epidermal cells grown in vitro. Four major polypeptide bands were greatly phosphorylated by EGF in a dose-dependent manner. The analysis of phosphorylated phosphoamino acids revealed that EGF stimulated tyrosine phosphorylation of pig epidermal fibrous keratin.

Animals↗