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Biomedical subjects

F Watanabe

Publications and source records attributed to F Watanabe.

At least 181 records · Page 10Linked to original sources
PubMed1991

Studies on Phe-228 and Leu-307 recombinant mutants of porcine kidney D-amino acid oxidase: expression, purification, and characterization.

Two recombinant mutants of porcine kidney D-amino acid oxidase [EC 1.4.3.3, DAO], in which Tyr(228) and His(307) are replaced with Phe and Leu, respectively, have been expressed in Escherichia coli and purified to apparent homogeneity. The molecular size and amino-terminal sequence of the two mutants were the same as those of the native DAO. Kinetic analysis revealed that the Michaelis constants of the Phe-228 and Leu-307 mutants for D-alanine were 71- and 10-fold and the inhibition constants for benzoate, a potent competitive inhibitor, were 1,189- and 18-fold greater than those of the native DAO, respectively. The maximum velocities of the Phe-228 and Leu-307 mutants were 66 and 58% that of the native DAO. The kinetically estimated dissociation constant of the Leu-307 mutant for FAD was 28-fold greater than that of the native DAO, whereas the value of the Phe-228 mutant was comparable to that of the native DAO. The Leu-307 mutant and the recombinant wild-type DAO were inactivated by D-propargylglycine (D-PG), a suicide substrate. However, the Phe-228 mutant was resistant to the inactivation. Absorption peaks of the Phe-228 mutant were blue-shifted about 10 nm from the corresponding peaks of the wild-type DAO, and the oxidized form was fully reduced by D-alanine without appearance of the purple intermediate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Synthesis of metabolites of S-1452, an orally active thromboxane A2 receptor antagonist.

The synthesis of 16 metabolites of S-1452, an orally active thromboxane A2 (TXA2) receptor antagonist, is described. Regioselective hydroxylation at C-5 or C-6 of the bicyclo[2.2.1]heptane skeleton of the optically active intermediate 16 was attempted by using 9-borabicyclo[3.3.1]nonane followed by H2O2 or m-chloroperbenzoic acid (m-CPBA) and then LiA1H4, to obtain the hydroxylated product 17a or 17b, respectively. Modification of the C-2 substituent of 17a and 17b afforded eight metabolites of S-1452. Eight non-hydroxylated metabolites were synthesized by using a similar reaction sequence.

Animals↗
PubMed1991

Occurrence and subcellular location of NADH- and NADPH-linked aquacobalamin reductases in human liver.

1. Both activities of NADH- and NADPH-linked aquacobalamin reductases were found in some human tissues, liver, kidney pancreas, heart, spleen, lung, cerebrum, cerebellum, adrenal glands, stomach, duodenum, jejunum, ileum, colon and bone marrow. 2. Human liver contained both enzymes with higher specific activities than any other tissues. 3. The liver NADH-linked enzyme was distributed in both mitochondrial (approx. 60%) and microsomal (40%) fractions; similar to the distribution of the NADPH-linked enzyme, but of which 40% activity was found in the mitochondria and the remaining activity was recovered in the microsomes. 4. The results suggest that the synthetic systems of the cobalamin coenzymes occur in both mitochondria and microsomes of human liver.

Cell Fractionation↗
PubMed1990

The transition of the higher-order structure of rat liver chromatin takes place at about 85% neutralization of DNA charges.

The salt dependence of the stoichiometry in the binding of linker histone to rat liver chromatin was analysed. It was found that the transition of the higher-order structure of chromatin (between folded and unfolded) takes place at the point of approximately 85% neutralization of DNA charges in chromatin, as in a related process in the B-Z transition of double-helical DNA.

Animals↗
PubMed1990

Mutagenicity of isoquinoline alkaloids, especially of the aporphine type.

The mutagenicity of 44 isoquinoline alkaloids was tested in Salmonella typhimurium TA100 and TA98 in the presence or absence of S9 mix. The alkaloids tested included compounds from the isoquinoline, benzylisoquinoline, bisbenzylisoquinoline, monoterpene isoquinoline, berberine, morphinane, hasubanan, benzo[c]phenanthridine and aporphine groups. Among the alkaloids tested, liriodenine was the most potent mutagen for TA100 and roemerine was the most potent for TA98. A clear structure-mutagenicity relationship was observed in a series of aporphine alkaloids (aporphine, dehydroaporphine, 7-oxoaporphine and 4,5-dioxoaporphine), and 10,11-non-substituted aporphines were suggested to exert their mutagenicity through metabolic activation of the 10,11 positions, possibly as the 10,11-epoxides.

Alkaloids↗
PubMed1990

[Heat distribution within the bone tissue by rotary cutting instrument for IMZ implant. Heat analysis by a real-time thermography].

A highly skilled surgical technic is an important factor for the success of implant. But the heat generation during bone preparation will greatly affect the healing process of bone and prognosis of implant. In this study, the heat occurrence and distribution during bone preparation which performed on an in vitro mandible model (ribs of pig) were considered with the aid of a real-time thermography. IMZ implant drills and bur, designed for cylindrical type implant were used for the bone preparation. The conclusion are as follows: 1. Any drill or bur generates higher heat without water irrigation. 2. Heat distribution produced different shape of range according to different type of drills. 3. On a relationship of preparating time to heat generation, spiral drill takes the longest time to complete drilling but heat rising ratio is slow. Round bur and Canon drill take short time to complete drilling but it is accompanied with rapid heat rising.

Animals↗
PubMed1990

Occurrence and tissue distribution of both NADH- and NADPH-linked aquacobalamin reductases in some vertebrates.

To elucidate the synthesis of cobalamin coenzymes in view of comparative biochemistry, tissue distribution of activity of aquacobalamin reductase [EC 1.6.99.8] catalyzing the reduction of hydroxocobalamin to cob(II)alamin was studied in some vertebrates. Activity of NADH- or NADPH-linked aquacobalamin reductase (or both) was found in some tissues of monkey, rat, cow, hog, chicken, fish, and frog. The liver homogenates of these vertebrates contained both NADH- and NADPH-linked enzymes. Monkey and rat livers accounted for more than 80% of total activities of both NADH- and NADPH-linked enzymes. Ratios of activities of the liver NADH- and NADPH-linked enzymes were above 1.0 in some land animals (monkey, rat, cow, and hog) but below 1.0 in water animals (sea and freshwater fishes). These different ratios are presumably due to the difference in the metabolisms of cobalamin and/or in the other cellular components between land and water animals.

Animals↗
PubMed1990

Clinical study on the prevalence of temporomandibular joint dysfunction in orthodontic patients.

The percentage of potential TMJ dysfunction is high in orthodontic patients. The prevalence of TMJ dysfunction during orthodontic treatment and the correlation between TMJ dysfunction occurrence and orthodontic appliances were studied. One hundred and twenty-five male and 183 female orthodontic patients between 7.2 and 38.3 years of age with a mean age of 13.1 years without TMJ dysfunction at first examination were examined for clinical symptoms. TMJ dysfunction was found in 26 patients (8.6%). The frequency of occurrence of TMJ dysfunction in patients treated with a chin cap appliance was 10.9% (14/129) and 6.7% (7/105) for those treated with a multibracket appliance. Chin cap appliance treatment was begun after the pubertal growth peak in eight patients, during the peak in three patients, and before the peak in three patients. Clinical symptoms continued in four patients who continued to use the appliance under the same conditions, and nine patients who were treated with proper countermeasures became free from clinical symptoms.

Adolescent↗
PubMed1990

[The clinical study on occurrence of TMJ dysfunction in orthodontic patients].

Occlusal disharmony is considered to be the most significant factor of temporomandibular joint (TMJ) dysfunction, but the relationship between malocclusion and TMJ dysfunction has been unknown yet. The purpose of present study was to investigate the relationship between TMJ dysfunction and occlusal disharmony (eccentric occlusal contacts and functional shift of the mandible) in orthodontic patients. The subjects were 533 orthodontic patients, 209 males and 324 females, who were received at the Department of Orthodontics, School of Dentistry, Hokkaido University from April 1985 to March 1988. Their ages ranged from 8 to 38 years old. All were prior to orthodontic treatment. The results were as follows 1. The prevalence of TMJ dysfunction was 27.6%, 24.9% in males and 29.3% in females. The difference was insignificant between males and females. 2. The patients with TMJ dysfunction increased after 13-15 years old, corresponding to dental age IV A (Hellman's classification). 3. In patients with TMJ dysfunction, the highest frequency of symptom of TMJ dysfunction was joint sounds (77.6%), the second was pain (22.4%), the third was disturbance of mandibular movement (4.8%). The complication of those symptoms were compounded in 26.3% of the total patients. 4. The prevalence of TMJ dysfunction had no relation to specific malocclusion and maxillofacial morphologic characteristic. 5. Most patients with TMJ dysfunction had occlusal disharmony (95.9%). 6. Eccentric occlusal contacts were found most frequently in patients with open bite and functional shift of the mandible was found most frequently in patients with deep bite. From these findings, the prevalence of TMJ dysfunction was frequent in orthodontic patients, however the symptoms were objective and the patients were not aware of TMJ dysfunction. TMJ dysfunction had no relation to specific malocclusion but some kinds of occlusal disharmony were easy to occur in specific malocclusion and TMJ dysfunction was induced by those etiological factors.

Adolescent↗
PubMed1990

[A case of brain metastasis from breast cancer responding to chemoendocrine therapy].

Brain metastasis is one of the most critical metastatic lesion on the treatment of breast cancer. We reported a case with brain metastasis from breast cancer responding to chemoendocrine therapy. The patient was 71 years old female complaining gait disturbance. Solitary brain metastasis and multiple bone metastases of breast cancer were diagnosed by CT scan and bone scintigram. Standard radical mastectomy was done. Estrogen receptor was proved to be positive in both of the tumor and metastatic lymph node. Tamoxifen and UFT were administered as chemoendocrine therapy. Complete response of brain metastasis was recognized in CT scan and gait disturbance was complete recovered two months after the treatment. She is now living well.

Aged↗
PubMed1989

Expression of normal and abnormal porcine kidney D-amino acid oxidase in Escherichia coli: purification and characterization of the enzymes.

Expression plasmids for normal and abnormal porcine D-amino acid oxidases (E.C. 1.4.3.3, DAO) have been constructed from cloned cDNA that encodes the entire protein sequence of DAO, and the enzymes were expressed in Escherichia coli cells on a large scale. The expressed enzymes were purified to apparent homogeneity. The molecular weight of the normal DAO (38 kD) was identical with that of DAO purified from porcine kidney, whereas that of the abnormal DAO was 39 kD, which comprised the normal DAO with an additional decapeptide at its amino terminus. However, the specific activities of the two enzymes were comparable with that of natural DAO. The results indicate that the bulky decapeptide does not affect the structure necessary for the catalytic function of DAO in the amino-terminal region. The use of a GTG triplet in the 5'-untranslated region of DAO cDNA as the initiation codon for the synthesis of the abnormal DAO is suggested.

Amino Acid Sequence↗
PubMed1989

NADH- and NADPH-linked aquacobalamin reductases occur in both mitochondrial and microsomal membranes of rat liver.

To elucidate the mechanism for the synthesis of the coenzyme forms of cobalamin in mammals, rat liver aquacobalamin reductase was partially characterized. Rat liver contained both NADH- and NADPH-linked aquacobalamin reductases. The NADH-linked enzyme was distributed in the mitochondria (approx. 40%) and microsomes (60%), identical to the distribution of the NADPH-linked enzyme. The two mitochondrial NADH- and NADPH-linked enzymes were located inside of the outer membrane.

Animals↗
PubMed1989

[Enzyme immunoassay of 17-hydroxyprogesterone in dried blood spot on filter paper using specific antibody for 17-hydroxyprogesterone].

Specific antiserum for 17-hydroxyprogesterone (17-OH-P) was prepared by immunizing 7 alpha-(2-carboxyethylthio)-17-OH-P conjugated bovine serum albumin (BSA) in rabbits. Using this antiserum, 17-OH-P enzyme immunoassay for dried blood spots on filter paper was established. As a label, alkaline phosphatase was coupled covalently with 7 alpha-carboxy-methylthio-17-OH-P by carbodiimide method. B/F separation was carried out by the addition of anti-rabbit IgG goat antiserum. All specimens used were punched out with a paper puncher of 3mm diameter. The assay sensitivity was 2pg/tube, which was estimated by two standard deviation at zero concentrations of the calibration curve. Cross reactivities of this antibody were as follows: 11-deoxycortisol (8.21%), 17-OH-pregnenolone (3.33%), progesterone (1.67%), 11-deoxycorticosterone (0.31%), cortisol (0.16%), pregnenolone-3-sulfate Na salt (0.03%), dehydroepiandrosterone (DHEA) (less than 0.03%), 16 alpha-OH-DHEA (less than 0.03%), DHEA-3-glucuronide (less than 0.03%), DHEA-3-sulfate Na salt (less than 0.03%), pregnenolone (less than 0.02%). Intra- and inter-assay coefficient of variations were 4-14% and 9-18%, respectively. In normal babies, 17-OH-P concentrations measured directly (without sample extraction) were below 23pg/disk (n=204). The histogram of 17-OH-P level in normal babies obtained by the direct method was distributed lower than that obtained by the enzyme immunoassay system (range: 4-79pg/disk, n=268) which used antibody raised against 17-OH-P-3-O-carboxymethyloxime conjugated BSA (Enzaplate, Sapporo Diagnostic Laboratory).(ABSTRACT TRUNCATED AT 250 WORDS)

17-alpha-Hydroxyprogesterone↗
PubMed1989

The role of charge neutralization and cooperative binding of linker histone in the higher-order structure of chromatin.

The binding mode and stoichiometry of interaction between soluble rat liver chromatin and histone H1 (H1) were studied. H1 binding to chromatin is cooperative. Chromatin accepts 3.6 molecules of H1/nucleosome at 0 M salt, close to the required ratio for neutralization of 90% of the charges on the phosphate groups of chromatin (4.0 H1 molecules/nucleosome). The proposal is put forward that critical charge neutralization (90%) has a significant influence on the irregular appearance of chromatin.

Animals↗