Search PubMed⌕ Search

Biomedical subjects

Y Miyake

Publications and source records attributed to Y Miyake.

At least 505 records · Page 28Linked to original sources
PubMed1987

Long-term effects of topically applied epinephrine on the blood-ocular barrier in humans.

Epinephrine (1.25%) was applied topically twice daily to both eyes of 22 patients with glaucoma or ocular hypertension. Half of these patients received topical indomethacin (0.5%) three times daily in one eye; the other half received indomethacin placebo under the same regimen. Blood-aqueous and blood-retinal barrier functions were determined by aqueous and vitreous fluorophotometry before and 1, 2, 3, and 7 months after initiation of treatment. Epinephrine-induced disruption of the blood-aqueous barrier, noted at two months, apparently remained constant until the completion of the study. At months 2, 3, and 7, indomethacin significantly inhibited this disruption. The blood-retinal barrier was unaffected. These results bear on the hypotensive mechanism of topically applied epinephrine.

Administration, Topical↗
PubMed1987

Adherence of Streptococcus mutans to implant materials.

The adherence of Streptococcus mutans OMZ-176 to six implant materials (poly-crystal alumina, single-crystal alumina, titanium alloy, cobalt-chromium-molybdenum alloy, hydroxyapatite, and heat-curing polymethylmethacrylate resin) was studied in vitro. The change of free energy, which corresponds to the adherence process, was also evaluated for hydrophobic interaction. Adherence of S. mutans to poly-crystal alumina was lower than adherence to other materials. The adherence of S. mutans to the test materials was highly correlated with the change of free energy, which suggests that hydrophobic interaction plays an important role in the adherence of S. mutans to the implant materials.

Alloys↗
PubMed1987

Effects of dose, pH, and osmolarity on nasal absorption of secretin in rats. II: Histological aspects of the nasal mucosa in relation to the absorption variation due to the effects of pH and osmolarity.

Nasal absorption of secretin in rats was enhanced in an acid solution, and the maximum absorption was observed at a sodium chloride solution molarity of 0.462. In order to examine reasons for the variation of absorbability caused by the change of pH and osmolarity in secretin preparations, both a pretreatment study, in which the nasal mucosa was treated with placebo prior to the administration of a secretin preparation, and a histological study were conducted in rats. The nasal absorption of secretin was determined by measuring the increased secretin of pancreatic juice. Similar profiles of nasal absorption, both after intranasal administration of secretin preparations and as a result of pretreatment effects, were obtained in studies of the effects of pH and osmolarity. However, in the pH-effect study, the absorption with the use of active preparations was observed to be significantly larger than that with the pretreatment effect below a pH of 4.79, and significantly smaller than that with the pretreatment effect at a pH of 7 to 8. The results of histological studies revealed structural changes of the epithelial cells of the nasal mucosa at pH 2.94, and shrinkage of epithelial cells was observed at a sodium chloride solution molarity of 0.462.

Absorption↗
PubMed1987

Electrophoretic studies of extracellular glucosyltransferases and fructosyltransferases from seventeen strains of Streptococcus mutans.

Streptococcus mutans was classified by the electrophoretic properties of glucosyltransferases (GTases) and fructosyltransferases (FTases). The cells of serotypes a, d and g did not release extracellular FTases, although those from other serotypes did. The enzymes from cells of serotypes d and g synthesized a good deal of insoluble polysaccharide compared with other serotypes. The enzymes were applied to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and polyacrylamide gel-isoelectric focussing (PAG-IEF). Gels were stained for their activity and protein content. Enzymes belonging to the same serotype gave the same specific pattern on both gels. The seven serotypes could be classified into the following four groups: serotypes d and g, serotype a, serotypes c, e and f, and serotype b. The results agree well with some previous reports based on other methods. The molecular weights of three GTase bands were 156K, 146K and 135K, and of four kinds of FTase bands were 108K, 95K, 80K and 76K. The isoelectric points of main enzymes were 4.25, 4.60, 5.00, 5.55 and 5.70. Those of FTases were 4.25 and 4.60.

Electrophoresis, Polyacrylamide Gel↗
PubMed1987

Effects of norepinephrine on lung fluid flow rate in the chronically catheterized fetal lamb.

The influence of norepinephrine on lung fluid flow rate was studied in seven chronically catheterized fetal lambs. Lung fluid was collected through a catheter inserted into the fetal trachea. In six experiments, continuous saline solution infusion for 1 hour followed by equivolumnar norepinephrine (3.0 micrograms/min) for 1 hour via the fetal jugular vein was carried out. In three additional experiments (two fetuses), a 3.0 mg intravenous bolus of propranolol was administered before norepinephrine infusion. Saline solution infusion did not influence the lung fluid flow rate or fetal biophysical and biochemical parameters. Norepinephrine increased fetal blood pressure by 22% and decreased lung fluid flow by 45% from control values. Lung fluid flow rate recovered within 2 hours after the end of the norepinephrine infusion. Pretreatment with propranolol did not alter the results. In addition to previous reports that demonstrated beta-sympathomimetic agonist-enhanced reabsorption of lung fluid from fetal alveolar epithelial cells, our present results suggest that a reduction in fetal lung fluid secretion may be implemented as well through stimulation of alpha-sympathomimetic receptor sites in the pulmonary vasculature.

Animals↗
PubMed1987

13C-NMR studies of porcine kidney D-amino acid oxidase reconstituted with 13C-enriched flavin adenine dinucleotide. Effects of competitive inhibitors.

D-Amino acid oxidase (DAO) from porcine kidney was reconstituted with FAD's which were enriched with 13C at the 2-, 4-, 4a-, and 10a-positions of the isoalloxazine moiety, and 13C-NMR spectra of the reconstituted DAO were measured in the absence and presence of various competitive inhibitors. When compared to the corresponding chemical shifts of FMN at infinite dilution (Moonen, C.T.W. et al. (1984) Biochemistry 23, 4859-4867), the resonances of C(2), C(4), C(4a), and C(10a) of FAD bound to apoDAO were all shifted to higher field. However, when the reconstituted DAO was complexed with o-, m-, p-aminobenzoate, or benzoate, each of the four 13C-signals underwent a different change in chemical shift. In these changes we observed no characteristics which distinguish DAO-aminobenzoate complexes from DAO-benzoate complex, even though o-, m-, and p-aminobenzoates are known to form charge-transfer complexes with DAO. The signals due to 2- and 4-13C were more sensitive to the formation of the inhibitor-DAO complexes than those of the other carbon atoms. These findings suggest the modulation of the hydrogen bonds at the oxygen atoms of C(2) = O and C(4) = O with the protein moiety as the result of the inhibitor-binding.

Animals↗
PubMed1987

Purification and characterization of cholesterol 7 alpha-hydroxylase cytochrome P-450 of untreated rabbit liver microsomes.

Cytochrome P-450 which catalyzes the 7 alpha-hydroxylation of cholesterol was purified from liver microsomes of untreated rabbits. The minimum molecular weight of the cytochrome P-450 was estimated to be 48,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The preparation contained 7 nmol of cytochrome per mg of protein. The oxidized form of the P-450 showed absorption maxima at 568, 535, and 417 nm, which are characteristic of a low spin hemoprotein, while the reduced form showed maxima at 545 and 413 nm. The carbon monoxide complex of the reduced form showed maxima at 550 and 447 nm. The cholesterol 7 alpha-hydroxylase system of untreated rabbit liver microsomes was reconstituted with the purified P-450, NADPH-cytochrome P-450 reductase, and cytochrome b5. The P-450 catalyzed the 7 alpha-hydroxylation of cholesterol 500 times more efficiently than the starting microsomes. The reconstituted hydroxylase system showed a substantial salt dependency. In the presence of cytochrome b5 the activity was maximum at 0.4 M KCl (4.55 nmol product formed/mg of protein per min), whereas in the absence of cytochrome b5 the activity was marginal (0.65 nmol product formed/mg of protein per min) and inhibited by KCl. Thus, cytochrome b5 stimulated the hydroxylase activity by one order of magnitude. These results indicate that cytochrome b5 is an essential component of the cholesterol 7 alpha-hydroxylase system of untreated rabbit liver microsomes.

Animals↗
PubMed1987

Cells of an internalization-defective familial hypercholesterolemia mutant secrete low density lipoprotein receptors.

Familial hypercholesterolemia (FH) is a congenital disorder of plasma low density lipoprotein (LDL) metabolism resulting from the defect or malfunction of LDL receptors on the cell surface. In most cases of FH, LDL binding to the cell surface is disrupted, while in some special cases LDL binding to the receptors occurs normally but the internalization of the bound LDL is inhibited (internalization-defective type). We studied the biosynthesis and transport of the LDL receptor in cultured fibroblasts obtained from one of the internalization-defective mutants by using [35S]methionine labeling and detection with anti-LDL receptor antibody. The mutant cells synthesized LDL receptors with a molecular weight slightly smaller than normal as shown in SDS-polyacrylamide gel electrophoresis. A large portion of the synthesized receptors was secreted into the medium while the other portion was associated with the cells. The apparent molecular weight of the receptors secreted into the medium was about 10 kDa smaller than that of the cell-associated receptors. The cell-associated form was converted into the secreted form following a prolonged incubation of the cells, showing the precursor-product relationship between the cell-associated and the secreted forms.

Antibodies, Monoclonal↗
PubMed1987

On the structure of old yellow enzyme studied by specific limited proteolysis.

Limited proteolysis of brewer's yeast old yellow enzyme (OYE) was carried out with bovine pancreatic alpha-chymotrypsin. The reaction proceeded with a decrease of the NADPH oxidase activity, generating specifically two peptides (designated as 34K and 14K fragments) with apparent molecular weights of 34,000 and 14,000, respectively. The same proteolytic treatment of apo OYE resulted in rapid and complete digestion of the protein. The 34K and 14K fragments are so intimately associated with each other that the isolation of each peptide from the other in the native form was unsuccessful. However, the complex of the two fragments was separated from the intact OYE and termed "nicked OYE." Nicked OYE still retained FMN and showed a visible-absorption spectrum slightly modified from that of intact OYE. Nicked OYE showed decreased affinity toward rho-bromophenol as compared to intact OYE. Nicked OYE exhibited lower Km and Vmax values than intact OYE in the NADPH oxidase reaction. The 34K and 14K fragments could be separated from each other by reversed-phase HPLC under denaturing conditions and the amino acid sequences of the two fragments and intact OYE in the amino terminal regions were determined. The N-terminal sequence of the 34K fragment coincided with that of intact OYE, indicating that the 34K fragment lies in the N-terminal side of OYE. The N-terminal sequence of the 14K fragment was found to show homology with the site of flavodoxin where it forms an electron-transfer complex with cytochrome c. The characteristic feature of this region is the presence of acidic residues and is shared by the FMN domain of NADPH-cytochrome P-450 reductase. We interpret these findings as indicating that OYE has a physiological role as an electron transfer component.

Amino Acid Sequence↗
PubMed1987

13C-NMR studies on the reaction intermediates of porcine kidney D-amino acid oxidase reconstituted with 13C-enriched flavin adenine dinucleotide.

The 13C-NMR spectra of the reaction intermediates of D-amino acid oxidase (DAO) were measured with DAO reconstituted with FAD in which the 2-, 4-, 4a-, and 10a-positions of the isoalloxazine moiety were selectively 13C-enriched. The reaction intermediates used include charge-transfer complexes of the oxidized DAO with substrate intermediates and those of the reduced enzyme with substrate intermediates. For the former type of complex, the reaction intermediates with beta-cyano-D-alanine (D-BCNA) and D-proline were used, while for the latter the purple intermediates with D-alanine and D-proline were chosen. The 13C-resonances of 2-13C in the reaction intermediates with D-BCNA and D-proline were downfield-shifted by about 1 ppm relative to the free oxidized DAO. The 4-13C signal for the DAO-D-BCNA intermediate was observed at 1.2 ppm upfield from that of the oxidized DAO, though that for DAO-D-proline intermediate showed no shift. These results suggest modulation of the hydrogen bondings at C(2) = 0 and/or C(4) = 0 in these reaction intermediates. Comparison of the 13C-resonances of reduced DAO with those of free reduced FMN in the neutral and anionic forms indicate that FAD in reduced DAO is in the anionic reduced form. The 4a-13C resonance of reduced DAO is upfield-shifted by about 3 ppm from that of free reduced anionic FMN. Comparison of the 13C-resonances for the purple intermediates with those of reduced FMN and reduced DAO indicate unequivocally that FAD in the purple intermediate is in the anionic reduced state. The 4a-13C resonances for the purple intermediates were substantially upfield-shifted (by 2.4 ppm with D-alanine and 1.9 ppm with D-proline) relative to reduced DAO. This indicates that the electron density, and hence the nucleophilicity, of the 4a-carbon is elevated in the purple intermediate relative to free reduced DAO. This leads to a model in which the oxidative half reaction proceeds via the reaction of molecular oxygen at the 4a-position of the reduced FAD in the purple intermediate. This provides a rational molecular basis for the oxidative half reaction by way of the purple intermediate prior to product release rather than by way of free reduced enzyme after product release.

Alanine↗
PubMed1987

Effects of mucopolysaccharides on penicillin-induced lysis of Staphylococcus aureus.

Effects of four mucopolysaccharides and dextran sulphate on penicillin-induced lysis of Staphylococcus aureus FDA 209P were studied. Heparin and dextran sulphate inhibited lysis, whereas hyaluronic acid enhanced it. Chondroitin sulphates A and C had no effect. Incubation of S. aureus suspended in 0.03 M phosphate buffer (pH 7.0) with dextran sulphate inhibited autolysis of the bacteria, whereas incubation with hyaluronic acid enhanced autolysis. Both extracellular and cell-associated autolysin activities of S. aureus were suppressed by dextran sulphate and high concentrations of heparin. The addition of hyaluronic acid enhanced autolysin activity. The release of lipoteichoic acid (LTA), a modulator of autolysin activity, from penicillin-treated bacteria was inhibited by heparin and dextran sulphate. However, hyaluronic acid had no effect on release of LTA. These results suggest that inhibition of penicillin-induced lysis of S. aureus by heparin results mainly from inhibition of LTA release while dextran sulphate inhibits both autolysin activity and LTA release. Hyaluronic acid appears to enhance penicillin-induced lysis through activation of the autolysins.

Bacteriolysis↗
PubMed1987

Effect of egg yolk lecithin on transdermal delivery of bunazosin hydrochloride.

Transdermal delivery of bunazosin HCl and the enhancing effect of egg yolk lecithin were examined using an in-vitro hairless mouse skin preparation and rabbits for in-vivo systemic absorption. The delivery of bunazosin in-vitro was small, but it was significantly enhanced when lecithin was incorporated into the same vehicle. This enhancing effect was confirmed with other drugs in-vitro. The enhancing ability was also seen in-vivo. Very little bunazosin was delivered from a propylene glycol suspension, but levels of 100-200 ng mL-1 were achieved by the incorporation of the lechithin.

Adjuvants, Pharmaceutic↗
PubMed1987

Extracellular products of Staphylococcus aureus reversibly inhibit the terminal differentiation of cultured mouse epidermal cells.

The effect of extracellular products from Staphylococcus aureus on the differentiation of mouse epidermal cells was studied using an in vitro cell culture system. The extracellular products from a clinical strain of S. aureus isolated from human skin lesions reversibly inhibited the Ca++-induced terminal differentiation of epidermal cells, as determined by their morphology and the extent of cornified envelope formation. This suggests that a similar modification of cell differentiation is involved in the pathogenesis of S. aureus-induced skin disease.

Animals↗
PubMed1987

[Basic and clinical evaluation of a new assay procedure "SCC RIABEAD" for estimation of squamous cell carcinoma related antigen].

We examined the efficacy of a new commercial assay procedure (SCC RIABEAD) for estimation of squamous cell carcinoma related antigen (SCC). Intraassay and interassay variance were 4.0-14.6% and 4.6-17.0% respectively. Recovery and dilution tests gave satisfactory results. The normal range was under the level of 1.63 ng/ml. The patients with uterine cervical cancer or squamous cell carcinoma of the lung showed high positive rates. The values of SCC measured by SCC RIABEAD were well-correlated to those by SCC RIAKIT. However, SCC RIABEAD showed lower values in low SCC level and higher values in high SCC level than SCC RIAKIT.

Adult↗