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Biomedical subjects

Y Miyake

Publications and source records attributed to Y Miyake.

At least 433 records · Page 24Linked to original sources
PubMed1989

Cerebral blood flow, oxygen and glucose metabolism with PET in progressive supranuclear palsy.

Cerebral blood flow, cerebral oxygen metabolic rate and cerebral glucose metabolic rate were measured with positron emission tomography (PET) in four patients with progressive supranuclear palsy (PSP). Decreased blood flow and hypometabolism of oxygen and glucose were found in both subcortical and cortical regions, particularly in the striatum including the head of the caudate nucleus and the frontal cortex. The coupling between blood flow and metabolism was preserved even in the regions which showed decreased blood flow and hypometabolism. These findings indicated the hypofunction, as revealed by decreased blood flow and hypometabolism on PET, both in the striatum and the frontal cortex, and which may underlie the pathophysiological mechanism of motor and mental disturbance in PSP.

Adult↗
PubMed1989

Pupillary fibrin membrane. A frequent early complication after posterior chamber lens implantation in Japan.

The incidence of pupillary fibrin membrane formation, a relatively frequent complication of cataract surgery in Japan even for experienced surgeons, was noted in 2038 consecutive cases of senile cataract removal and primary posterior chamber intraocular lens (PC IOL) implantation. The overall incidence was 4.4%. Comparisons among cases showed the incidence to be significantly higher among: (1) patients who received dry- versus wet-sterilized lenses (P less than 0.001), (2) eyes with premature, subcapsular, or nuclear cataracts than among those with mature cataracts (P less than 0.05), (3) patients with systemic hypertension (P less than 0.01), (4) eyes not treated postsurgically with topical antiprostaglandins (P less than 0.001), and (5) patients who had undergone previous PC IOL implantation in the fellow eye (P less than 0.001). These findings suggest that the formation of the fibrin membrane is a kind of immunologic reaction. Accordingly, use of antiprostaglandin agents and complete removal of lens material and epithelial cells are recommended, especially for patients undergoing second-eye operations or those with a predisposition to breakdown of the blood-aqueous barrier.

Aged↗
PubMed1989

Aminoglycosides enhance the adherence of Staphylococcus aureus to HeLa cells.

Sub-lethal concentrations of aminoglycosides enhanced the adherence of Staphylococcus aureus FDA 209P to HeLa cells, whereas beta-lactams, pyridone carboxylic acid derivatives and chloramphenicol did not. Treatment with aminoglycosides also enhanced the bacterial adherence of these cells to immobilized fibronectin and laminin, and changed the bacterial cell surface to a more hydrophilic state than exists in non-treated cells. The adherence of S. aureus was not inhibited by lipoteichoic acid, extracted from the same strain, regardless of whether the bacterial cells were treated with an aminoglycoside or not. No correlation was observed between the adherence and zeta-potential of S. aureus.

Aminoglycosides↗
PubMed1989

Identification and structure of the rat true tissue kallikrein gene expressed in the kidney.

Genomic clones carrying the entire rat true tissue kallikrein gene have been isolated and characterized. Southern blot analysis revealed the presence of a unique gene for true tissue kallikrein in the rat haploid genome. The true tissue kallikrein gene was composed of 5 exons and 4 introns, its length being about 4.5 kilobase pairs. We also isolated the rat renal kallikrein cDNA which was expressed in the kidney. The exon sequences of the gene were identical with the corresponding sequences of the kallikrein cDNA. The rat true tissue kallikrein gene was distinct from two rat kallikrein-related genes expressed in the kidney (Chen, Y. et al. (1988) Biochemistry 27, 7189-7196). Primer extension analysis indicated that two identical transcription-initiation sites were used in both the kidney and submandibular gland, although expression of the true tissue kallikrein in the submandibular gland was much higher than that in the kidney. The 3'-noncoding region of this gene contained the polyadenylation signal, AATAAA, observed in the rat renal kallikrein cDNA. The 5'-flanking region was sequenced up to about 800 base pairs, upstream of the cap sites. CATCT, GGGCGG, and TTTAAA boxes were found as common signals required for eukaryote gene expression within about 100 base pairs-upstream of the cap sites.

Animals↗
PubMed1989

Site-specific mutagenesis of lysine-204, tyrosine-224, tyrosine-228, and histidine-307 of porcine kidney D-amino acid oxidase and the implications as to its catalytic function.

In order to evaluate the possible contributions of Lys-204, Tyr-224, Tyr-228, and His-307 in porcine kidney D-amino acid oxidase [EC 1.4.3.3] (DAO) to its catalytic function, we constructed four point mutant cDNAs encoding enzymes possessing Glu-204, Phe-224, Phe-228, and Leu-307 by oligonucleotide-directed in vitro mutagenesis. The four mutant cDNAs and the wild type cDNA could be expressed in vitro with similar efficiencies and about 200 ng of each enzyme protein was produced from 5 micrograms of the respective capped RNA. The electrophoretic mobilities of the in vitro synthesized mutant enzymes on SDS-polyacrylamide gel were almost identical with that of the wild type DAO, and the molecular weight was calculated to be 38,000. The Glu-204 and Phe-224 mutant DAOs showed comparable enzyme activities to that of the wild type enzyme, and were inhibited strongly by sodium benzoate, a potent competitive inhibitor of DAO. The kinetic parameters of the two mutant DAOs were also comparable to those of the wild type DAO. On the other hand, the Phe-228 and Leu-307 mutant DAOs showed no detectable activity. The results indicate that Tyr-228 and His-307 play important roles as to the constitution of the active site or participate in the reaction directly, while Lys-204 and Tyr-224 are not essential in the enzyme reaction.

Animals↗
PubMed1989

Binding of both Ca2+ and mastoparan to calmodulin induces a large change in the tertiary structure.

The technique of small-angle X-ray scattering has been employed to examine the solution conformation of calmodulin and its complexes with Ca2+ alone, and with both Ca2+ and mastoparan. The radius of gyration decreased by 3.1 +/- 0.3 A upon binding of both 4 mol Ca2+/mol of protein and 1 mol mastoparan/mol of protein to form the ternary complex. A smaller increase was found for the separate binding of 4 mol Ca2+/mol of protein in the absence of mastoparan (0.6 +/- 0.3 A). The analyses of pair distance distribution function showed that the maximal pair distance in calmodulin complex with both Ca2+ and mastoparan decreased by 20-30% in comparison with calmodulin or its complex with Ca2+, and a shoulder near 40 A, which characterizes the dumbbell-shaped molecule of calmodulin, disappeared. These results indicate that the two globular domains of the calmodulin complex with Ca2+ and mastoparan come close together by 8.0-9.5 A on average, if the size and the overall shape of the globular domains are the same in Ca2+-calmodulin-mastoparan complex as in calmodulin or Ca2+-calmodulin complex.

Animals↗
PubMed1989

Changes in trypsin-binding properties and conformation of rabbit alpha-2-macroglobulin on reaction with methylamine.

Reactions of rabbit alpha-2-macroglobulin with methylamine and trypsin were studied and the results were compared with those obtained for previously described 2-macroglobulins from other species. Rabbit alpha-2-macroglobulin was cleaved by trypsin at a number of sites, whereas the human homologue was split essentially only in the "bait" region into two fragments of similar sizes. Reaction of native or methylamine-treated rabbit alpha-2-macroglobulin with trypsin resulted in a substantial decrease in the intensity of fluorescence induced by binding of 6-(p-toluidino)-2-naphthalenesulfonate or bis(8-anilino-1-naphthalenesulfonate). Under the same conditions, the fluorescence of the human protein increased. The time course of the reaction of rabbit alpha-2-macroglobulin with methylamine was studied by measuring (i) the generation of thiol groups, (ii) the decrease in trypsin-inhibiting activity with remazol brilliant blue hide powder as the substrate, and (iii) the decrease in trypsin-protein amidase activity. The thiol appearance reaction exhibited a multiphasic time course. The initial phase was found to follow second-order kinetics with an apparent rate constant of 1.2 M-1.s-1. Under the same conditions, the human protein showed monophasic kinetics with a rate constant of 12 M-1.s-1. Both the trypsin-inhibiting activity and the trypsin-protein amidase activity concurrently decreased at a slower rate than the thiol appearance. These results indicate that rabbit alpha-2-macroglobulin is more stable to nucleophilic attack by methylamine but less resistant to proteolysis by trypsin than the human homologue, and that the final conformation induced by methylamine differs considerably from that induced by trypsin.

Animals↗
PubMed1989

Rectal absorption of E-2078 (dynorphin analogue peptide) in rats.

The plasma levels in rats of a dynorphin analogue peptide (E-2078) after rectal administration have been studied. The bioavailabilities of E-2078 after rectal administration, subcutaneous injection, intramuscular injection, and oral administration were 21.6, 67.8, 67.1, 0.7%, respectively. The effect of dose, pH, osmolarity and viscosity on the rectal absorption of E-2078 were studied. A sigmoid relationship between the dose and the AUC was observed on rectal administration, while there was a linear relationship on intramuscular administration. The AUC was increased in acidic solution and highly viscous solution. The osmolarity did not affect the absorption of E-2078. In microscopic studies, E-2078 caused little or no damage to the rectal mucosa in rats.

Administration, Oral↗
PubMed1989

Fetal blood values by percutaneous umbilical blood sampling.

Cordocentesis was performed, and fetal blood was sampled in 81 of 93 attempted procedures. In 45 fetuses, who proved to be normal later by normal pregnancy outcome, hematological analyses and blood chemistries were performed. The results showed an increase in total white blood cell count, red blood cell, hemoglobin, hematocrit and platelet count, while the mean corpuscular volume and mean corpuscular hemoglobin decreased during gestation. Total protein and albumin concentrations increased during pregnancy. These results provide information for the diagnosis of fetal hematological disorders, and assist in making decisions for possible fetal therapy in utero.

Female↗
PubMed1989

A mental health survey of the Vietnamese refugee in Japan.

A mental health survey was conducted using the Cornell Medical Index (CMI) on Vietnamese refugees who have resettled in Japan. 64.5% of the females and 37.2% of the males displayed emotional disturbance. The refugees with life-threatening and/or concentration camp experience had significantly higher CMI scores than those without it (t test, P less than 0.05). CMI scores of the group residing in Japan for 4-5 years are markedly lower than the group residing there for 2-3 years (F test, P less than 0.05).

Acculturation↗
PubMed1989

Kinetic study on the mechanism of inhibition of trypsin and trypsin-like enzymes by p-guanidinobenzoate ester.

It was found that [4-(2-succinimidoethylthio)phenyl 4-guanidinobenzoate]methanesulfonate (E-3123) inhibits trypsin, thrombin and kallikrein, and its inhibitory activity is most potent toward trypsin. The interactions of these enzymes with E-3123 were studied mainly by using stopped-flow spectrophotometry. E-3123 behaved as a quasi-substrate of the enzymes and the inhibitory property was due to the efficient production of the stable acyl-enzyme. The acylation process with trypsin was exceedingly effective, and the resulting acyl-enzyme was the most stable among the three enzymes tested. This observation affords a rational basis for explaining the action of E-3123, which is a transient inhibitor most active toward trypsin.

Guanidines↗
PubMed1989

The effect of ofloxacin on experimental periodontitis in hamsters infected with Actinomyces viscosus ATCC 15987.

Syrian hamsters were infected with Actinomyces viscosus ATCC 15987 by inoculation into the oral cavity to induce experimental periodontitis. The effect of an antibiotic, ofloxacin (OFLX), on the experimental periodontitis was examined. In Group A, OFLX gel was applied daily to the gingival mucosa, 2 weeks after bacterial inoculation. Groups B and C were an infected control and a noninfected control, respectively. The hamsters in these three groups were fed a powdered high-sucrose diet. The hamsters in Group D, also a noninfected group, were fed an ordinary solid diet. Salivary occult blood test, evaluation of gingival and plaque index, measurement of alveolar bone loss, bacterial examination, and histological observation were performed 11 weeks after infection. Group B exhibited significantly higher levels of gingival index, plaque index, and alveolar bone loss than the noninfected controls. Severe inflammation of the gingivae, formation of gingival pockets, migration of many inflammatory cells, and obvious bone loss were also observed in Group B. However, these inflammatory changes were milder in Group A, which was treated with OFLX.

Actinomyces↗
PubMed1989

Bronchoconstrictive properties and potentiating effect on bronchial responsiveness of inhaled thromboxane A2 analogue (STA2) in guinea pigs.

Effect of subthreshold concentration of inhaled STA2, a thromboxane A2 (TXA2) analogue, on bronchial responsiveness to histamine was investigated in anesthetized and artificially ventilated guinea pigs. Percent increase in pressure of the airway opening (Pao) by aerosol histamine (50, 100 micrograms/ml) was significantly potentiated by subthreshold dose of aerosol STA2 (0.10 micrograms/ml) which was determined by dose-response curve of % increase in Pao by inhaled STA2 (0.033, 0.10, 0.33, 1.0 micrograms/ml). These results demonstrated that thromboxane A2 could contribute to bronchial hyperresponsiveness which is one of the major clinical features of bronchial asthma.

Aerosols↗
PubMed1989

The placental and mammary transport of [14C]menaquinone-4 in rats.

The transfer of menaquinone-4 (vitamin K2(20] to the fetus and milk was studied in pregnant and lactating rats, respectively, after oral administration (4 mg/kg) of [3'-14C]menaquinone-4. Intestinal absorption of menaquinone-4 was rapid and the highest level of radioactivity in each tissue except guts of fetal rats was observed at 4h after dosing. The level in the fetal homogenate was low. At that time, the concentration of menaquinone-4 in the fetal liver was 84 ng/g, corresponding to 9% of the value found in the placenta. Therefore, we conclude that the transfer of menaquinone-4 to the developing rat fetus is restricted by the blood-placenta barrier, but that a sufficient amount of menaquinone-4 (more than the essential amount of vitamin K to ensure full carboxylation) can be transferred into the fetal liver. It was also observed that the radioactivity was transferred to milk after oral administration to lactating rats. Milk/blood concentration ratios at 6 and 24h after dosing were 13.8 and 65.1, respectively. The elimination half-life of radioactivity in milk was about 17h. Eighty-four percent of milk of radioactivity was due to menaquinone-4. These results suggest that the prophylactic maternal oral administration of menaquinone-4 may be efficacious for a prophylaxis of neonatal and infantile vitamin K deficiency.

Animals↗
PubMed1989

[Automatic boundary detection and pathological diagnosis of the maxillary sinus].

A method for automatic boundary detection of the maxillary sinus from a cranial X-ray radiograph has been developed. An algorithm using the local segmental properties of the X-ray image to transform a continuous tone image into a bi-level image is introduced. In addition, the global shape information such as the area, the perimeter, and the complexity, are considered for the boundary detection. The boundary of the maxillary sinus detected by this method coincided precisely with the area plotted-by experienced otolaryngologists. Furthermore, the cumulative distribution function (CDF) calculated from the density histogram of the maxillary sinus has been employed to perform the tonal evaluation of the intra-maxillary pathological changes. The distance between the CDFs successfully demonstrated the difference in pathological stages of the chronic sinusitis.

Humans↗