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Biomedical subjects

R Okamoto

Publications and source records attributed to R Okamoto.

At least 235 records · Page 13Linked to original sources
PubMed1986

Radical synovectomy with muscle release for the rheumatoid elbow.

Twenty-three synovectomies of the elbow with concomitant muscle release at the humeral epicondyles were performed in 21 patients with rheumatoid arthritis. Ten elbows were classified as anatomical Stage 2, 12 as Stage 3, and one as Stage 4. The patients were followed from 1 to 8 years. Postoperative clinical results showed improved relief of pain, and range of motion, and activities of daily living. Increased range of motion with improvement of flexion contracture was obtained in most cases by releasing the muscle insertions around the humeral epicondyles and by resecting the radial head and bony spurs of the coronoid and the olecranon. The operation was beneficial even at advanced stages.

Adult↗
PubMed1986

Thymidylate synthetase and thymidine kinase activities in DMH-induced colon carcinomas in rats and effects of UFT.

Carcinoma of the colon was induced in rats by injection of a carcinogen 1,2-dimethylhydrazine (DMH), and thymidylate synthetase (TS) and thymidine kinase (TK) activities, which catalyze the biosynthesis of dTMP by the de novo pathway and the salvage pathway of pyrimidine synthesis, respectively, were measured in normal control colon, DMH-treated normal colon, and DMH-induced colon carcinoma with or without administration of two doses of an anti-cancer drug UFT (a combination of tegafur and uracil). TS and TK activities were both increased after treatment with DMH, markedly in colon carcinoma tissue, and to a lesser degree in normal-appearing colon tissue. This phenomenon is well explained by the hypothesis that biochemical alterations of DNA-synthesizing enzyme activities occur as a preliminary step prior to the development of overt cancerous transformation. A low dose of UFT inhibited TS activity but enhanced TK activity, therefore, the salvage pathway may compensate for the reduced level of the de novo synthesis. On the other hand, a large dose of UFT reduced both TS and TK activities, perhaps due to cytotoxic effects of UFT incorporation into RNA.

1,2-Dimethylhydrazine↗
PubMed1986

Antibacterial activity and ototoxicity in guinea pigs, and nephrotoxicity in rats of arbekacin.

Arbekacin (HBK), 1-N[(S)-4-amino-2-hydroxybutyl]-3',4'-dideoxykanamycin B, showed broad antibacterial spectra against gram-positive and gram-negative bacteria including Pseudomonas aeruginosa. It was also effective against gentamycin- or tobramycin-resistant bacteria. HBK was resistant to various aminoglycoside-inactivating enzymes except for AAC (2') and AAC (6')-IV, both of which slowly inactivated it. Even at higher dosages (150 mg/kg i.m. or greater, which resulted in some deaths), HBK never decreased the pinna reflex in guinea pigs, while 150 mg/kg or more of dibekacin (DKB) or amikacin (AMK) caused loss of this reflex. HBK has less ototoxicity than do DKB and AMK. This was confirmed by histopathological examination of the inner ear. The degree of nephrotoxicity of HBK was suggested to be similar to that of DKB as judged from serum biochemical tests, urinalysis, and histopathological findings.

Amikacin↗
PubMed1985

Resection of painful shelf (plica synovialis mediopatellaris) under arthroscopy.

In a series of 3,250 patients with knee disorders, a painful shelf was diagnosed and resected in 39 knees of 32 patients. Thirty of them were done by arthroscopy and nine by arthrotomy. There were 10 men and 22 women whose ages ranged from 4 to 55 years, with an average of 19 years. The follow-up period ranged from 1 to 6 years. Postoperatively, the pain was relieved in 26 knees and diminished in 13. A cord-like mass, palpable in 30 knees, disappeared in 25 postoperatively. Clicks were noted in 34 knees; 28 of these were not audible or palpable postoperatively. The provocation test 1 result was positive in 23 of 28 knees preoperatively, negative in 21, and diminished in 2 postoperatively. The provocation test 2 was performed in 23 knees; it produced pain and/or palpable click in 14 preoperatively, and was negative in 12 and diminished in 2 postoperatively.

Adolescent↗
PubMed1985

Increased activities of thymidine kinase isozymes in human colon polyp and carcinoma.

Thymidine kinase (TK), the enzyme in the pyrimidine salvage pathway, and its isozymes were examined in 15 specimens of normal mucosa, 14 polyps and 14 carcinomas in human colon. The average TK activities in colon polyps and carcinomas were about 1.6 and 2.9 times that in normal colon mucosa, respectively. The colon TK isozymes were separated into 2 types by DEAE-cellulose column chromatography. The activity of the TK isozyme eluted with 0.1 M NaCl in buffer was 1.6-fold higher in colon polyp and 1.5-fold higher in colon carcinoma than that in normal colon mucosa. In colon carcinoma, but not colon polyp, the activity of the other isozyme eluted with buffer alone was increased to 5.1-fold that in normal tissues. As the activity of the latter isozyme was not affected by deoxycytidine triphosphate, it may be involved in DNA replication. The results suggest that increases in the activities in the former and latter TK isozymes may indicate tumorigenesis and carcinogenesis, respectively, in the human colon.

Adult↗
PubMed1985

Biochemical properties of beta-lactamase produced by Flavobacterium odoratum.

A constitutively produced beta-lactamase was purified from Flavobacterium odoratum GN14053. The purified enzyme gave a single protein band on polyacrylamide gel electrophoresis. The isoelectric point was 5.8, and the molecular weight was estimated to be about 26,000. The enzyme activity was inhibited by EDTA, iodine, p-chloromercuribenzoate, HgCl2, and CuSO4 but not by clavulanic acid, sulbactam, imipenem, and cephamycin derivatives. The enzyme showed a broad substrate profile, hydrolyzing oxyiminocephalosporins, cephamycins, imipenem, and some penicillins.

Anti-Bacterial Agents↗
PubMed1984

[The extraction of biologically active substances from hop].

Substances which suppressed the effect of gonadotropin in the rat were obtained from hop. These biologically active substances were fractionated from the hop cone, from which lipophilic components (total resins) were removed with acetone. They were water soluble, 70,000-80,000 in molecular weight and were composed mainly of neutral sugars and uronic acid. Administration of the substances to immature rats primed with pregnant mare's serum gonadotropin (PMS) resulted in the following: a significant decrease of ovarian weight gain, whereas there was no change in uterine weight gain, and significant reductions of serum LH and progesterone from cultured luteal rat cells.

Animals↗
PubMed1984

Proline hydroxylation by cell free extract of a streptomycete.

Free L-proline was hydroxylated to free L-hydroxyproline by cell free extract of Streptomyces griseoviridus P8648. The hydroxylation reaction required ferrous ion, 2-ketoglutarate and ascorbate. Zinc ion, ethylenediaminetetraacetic acid and alpha,alpha'-dipyridyl inhibited the reaction. Optimum temperature and pH were 25.0 degrees C and 7.5, respectively.

Hydrogen-Ion Concentration↗
PubMed1984

Effect of hypoxia on cholesterol accumulation in cultured rabbit aortic smooth muscle cells.

We studied the effect of hypoxia on cholesterol accumulation in cultured rabbit aortic smooth muscle cells, which were incubated in a medium with normolipemic rabbit serum (NRS) or hyperlipemic rabbit serum (HRS). The cells were incubated in a humidified atmosphere of either 20% O2, 75% N2 and 5% CO2 (control cells) or 2% O2, 93% N2 and 5% CO2 (hypoxic cells). In a medium containing 20% NRS, the free cholesterol level of hypoxic cells was only a little higher than that of control cells, and there was no significant difference in esterified cholesterol content. On the other hand, in a medium containing 20% HRS, the free cholesterol level was slightly higher and the esterified cholesterol level was markedly higher in hypoxic cells compared with control cells. These results show that hypoxia promotes the accumulation of cholesterol, especially as ester, in smooth muscle cells cultured with hyperlipemic serum. These in vitro experiments indicate that hypoxia in the arterial wall associated with hyperlipidemia may play an important role in atherogenesis, although the precise mechanism remains unclear.

Animals↗
PubMed1984

Extraction of the hormonal substance from hop.

Substances that suppressed a gain in the weight of pregnant mare's serum gonadotropin (PMSG)-primed immature rat ovaries, were obtained from dried powder of the hop cone. The substances were designated F1a-I and F1a-II. In immature rats at 4 days after PMSG priming, ovarian weights decreased by 58.0 +/- 3.7 and 66.9 +/- 6.6% the control by injections with 4 mg each of F1a-I and F1a-II, respectively. Apparent M1s of the partially purified fractions were nearly 80000 (F1a-I) and 66000-80000 (F1a-II). They were water-soluble. Acidic and neutral sugars were detected in the hydrolysate of the substance.

Animals↗
PubMed1984

Effects of estrogen and prolactin on thymidine kinase isozyme activities in DMBA-induced rat mammary tumor.

Effects of prolactin or estrogen on the activity of the pyrimidine salvage pathway enzyme thymidine kinase (TK) in 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors were investigated in ovariectomized rats. Prolactin induced by perphenazine administration significantly enhanced the activities of total TK or its isozyme in the tumors. This specific TK isozyme separated by DEAE-cellulose column chromatography was suggested to be involved in DNA synthesis because it was not affected by dCTP. Its Mr was estimated to be approx. 100 000 by high-performance liquid chromatography. In contrast, estrogen alone did not raise the activity of the specific TK isozyme in the tumors.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Increased activity of thymidine kinase isozyme in human colon tumor.

Thymidine kinase (TK), the salvage pathway enzyme, and its isozymes were examined in normal mucosa and carcinoma of the colon in 13 patients. In colon tumor TK activity increased to 328% of activity of normal colon. The colon TK isozymes were separated from the normal mucosa and carcinoma by DEAE-cellulose column chromatography. The TK isozyme eluted from the column by the elution buffer alone without NaCl was markedly higher (12-fold) in activity in carcinoma than in normal mucosa of the colon and is not affected by dCTP. The TK isozyme unaffected by dCTP has also been reported to be clearly involved in DNA synthesis. This isozyme, whose molecular weight is 100 000 by means of high performance liquid chromatography, is thought to be involved in DNA replication. The results indicate the applicability of the molecular correlation concept to carcinogenesis of colon.

Aged↗
PubMed1983

Effects of estrogen and progesterone on thymidine kinase activity in the immature rat uterus.

The effects of progesterone and/or 17 beta-estradiol on thymidine kinase activity and autoradiograms were investigated in immature rats. Thymidine kinase activity increased more than thirtyfold above the control level 30 hours after 17 beta-estradiol injection. The enzyme activity induced by 17 beta-estradiol was suppressed by progesterone, the dose of which was approximately 1,000-fold that of 17 beta-estradiol. The specific thymidine kinase isozyme, which was separated from 17 beta-estradiol-induced uterine thymidine kinase by diethylaminoethyl (DEAE) cellulose column chromatography and not affected by deoxycytidine triphosphate, was involved in the DNA replication and inhibited by progesterone. The autoradiogram revealed many grains due to 3H-thymidine in the endometrial epithelium, stroma, and the myometrium in the immature rat 30 hours after 17 beta-estradiol injection, whereas progesterone reduced remarkably the number of grains induced by 17 beta-estradiol in the epithelium. Progesterone seems to inhibit the increment of the specific thymidine kinase isozyme induced by 17 beta-estradiol in the endometrial epithelium.

Animals↗
PubMed1983

Synergistic effect of estrogen and androgen on induction of uterine thymidine kinase activities in immature rats.

Estradiol-17 beta induced a significant increase in the uterine thymidine kinase activity with a characteristic isozyme pattern 30 h after injection into immature rats. Testosterone propionate also revealed a similar increase. Following combined injection of estradiol-17 beta and testosterone propionate, the overall and separate isozyme activities of thymidine kinase increased to nearly the total amount of those when each hormone was injected separately.

Animals↗