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Biomedical subjects

N Okada

Publications and source records attributed to N Okada.

At least 577 records · Page 32Linked to original sources
PubMed1976

Specific replacement of Q base in the anticodon of tRNA by guanine catalyzed by a cell-free extract of rabbit reticulocytes.

Guanylation of tRNA by a lysate of rabbit reticulocytes was reported previously by Farkas and Singh. This reaction was investigated further using 18 purified E. coli tRNAs as acceptors. Results showed that only tRNATyr, tRNAHis, tRNAAsn and tRNAAsp which contain the modified nucleoside Q in the anticodon acted as acceptors. Analysis of the nucleotide sequences in the guanylated tRNA showed that guanine specifically replaced Q base in these tRNAs.

Animals↗
PubMed1976

In vitro and in vivo evaluation of ceftezole, a new cephalosporin derivative.

Ceftezole, a new cephalosporin derivative, was compared with cefazolin, cephaloridine, and cephalothin. Data obtained indicate that it is a broad-spectrum antibiotic, with almost identical antimicrobial activity against pathogenic organisms isolated from patients. The therapeutic effect of ceftezole on experimental infections in mice was similar to that of cefazolin and was superior to that of cephalothin. The binding of ceftezole to serum proteins was somewhat less than that of cefazolin. The concentrations of ceftezole in the sera of test animals and human volunteers were determined after intramuscular injection of 20 mg/kg and after a single dose of 500 mg, respectively. The concentration of ceftezole in the serum of volunteers peaked at 24.9 mug/ml 15 min after injection and remained effective (about 2.6 mug/ml) at 4 h. The half-life in serum under the same conditions was 56 min, i.e., about one-half that of cefazolin. The 24-h urinary recovery rate was 87.5%. Most of the administered ceftezole was excreted unchanged mainly through the urinary tract. The biliary excretion rate in SD strain rats after intramuscular injection of 20 mg/kg was about 4.4%. As compared with commercially available cephalosporins, ceftezole was second only to cefazolin in biliary excretion rate. Various tissue levels of ceftezole in animals were higher than cephalothin but, with the exception of renal levels in the early stage after administration, were lower than cefazolin.

Adult↗
PubMed1976

Fatty acid composition of adipose tissue and liver fats of the rats fed yeast grown on n-alkanes.

n-Alkane assimilating yeast, Candida tropicalis YO-148, was grown on an n-alkane-containing medium. A synthetic diet containing 6.8% of dried yeast was fed to rats. The fatty acid composition of adipose tissue and liver fats was determined after a two week feeding period. The percentage of odd-numbered acids increased in the animals fed the yeast diet. Furthermore, it was shown that heptadecenoic acid, the major odd-numbered acid in yeast, was accumulated in neutral lipid fraction of adipose tissue fat. Fatty acid composition of protein isolate prepared from yeast cells had a profile similar to that of the original cells.

Adipose Tissue↗
PubMed1976

Laboratory evaluation of FR10612, a new oral cephalosporin derivative.

FR10612, like cephalexin, is a broad-spectrum oral cephalosporin derivative. The antimicrobial activity of FR10612 against clinical isolates was similar to cephalexin; however, at a low inoculum size its activity was greater than cephalexin against Klebsiella pneumonia and Proteus mirabilis strains. Like cephalexin, the in vitro bactericidal activity of FR10612 was more influenced by the duration of contact with the test organism than by drug concentration. The bactericidal activity of FR10612 against E. coli 317 was greater than that of cephalexin in an in vitro model system which simulated the serum levels of FR10612 and cephalexin achieved in healthy volunteers after a single oral dose. The protein binding of FR10612 to human and animal serum was extremely low. FR10612 was resistant to beta-lactamases from gram-negative bacilli. It showed resistance similar to cephalexin, but was more resistant to beta-lactamases than were cephaloridine, cephalothin and cefazolin. The protective effect of FR10612 in mice infected with various pathogens was greater than cephalexin. The serum levels of FR10612 in rats were higher and more prolonged than those of cephalexin. Tissue levels of FR10612 in rats also persisted for a long time period reflecting the serum levels. In healthy volunteers, rabbits and monkeys the serum levels of FR10612 were initially lower than those of cephalexin but persisted for a longer time period. The total 24-hour urinary excretion of FR10612 in healthy volunteers after oral administration was almost the same as that of cephalexin, but the excretion rate of FR10612 was slower, and the urinary levels were more persistent than those of cephalexin.

Animals↗
PubMed1976

Comparative studies on the antitumor effect on intravenous administration of carbazilquinone and mitomycin-C.

Comparison between Carbazilquinone and Mitomycin-C, both of which contain aziridinyl, carbamoyloxy, and quinonyl groups, was made for their therapeutic effect upon intravenous administration. Although both agents exhibited a significant effect on plasmacytoma X5563 in C3H/He mice to a similar extent, Mitomycin-C was not as effective on lympholeukemia L-1210 and on the lung metastasis of Ehrlich carcinoma in (C57BL/6 X DBA/2)F1 (BDF1) mice as was Carbazilquinone. Possible interpretations regarding this discrepancy are discussed.

Animals↗
PubMed1975

Radioimmunoassay for plasma betamethasone 17-benzoate.

A sensitive radioimmunoassay for plasma betamethasone 17-benzoate has been developed. The antiserum used was obtained by immunizing rabbits with betamethasone 17-benzoate-21-hemisuccinate-bovine-serum-albumin conjugate. All of the endogenous steroids tested cross reacted less than 0.10%. A standard curve was established with a useful range from 0.05-5 ng. Reliability criteria were satisfactory. Measurement of plasma concentrations of betamethasone 17-benzoate was performed in patients and in rabbits following occlusive dressing of betamethasone 17-benzoate cream and gel base.

Animals↗
PubMed1975

[Pharmacological study of 9 alpha-fluoro-11 beta, 17, 21-trihydroxy-16 beta-methylpregna-1, 4-diene-3,20-dione-17-benzoate (betamethasone-17-benzoate, MS-1112), a local anti-inflammatory agent. (1). Its anti-inflammatory and other pharmacological properties].

The anti-inflammatory activity and the other pharmacological properties of MS-1112, a new steroid compound, were examined and compared with other glucocorticoid analogues such as hydrocortisone acetate (Hydr), betamethasone 17-valerate (Val) and dexamethasone (Dexa). Systemically administered MS-1112 and glucocorticoids had a significant effect in inhibiting rat paw edema induced by various phlogistic stimulations and increasing vascular permeabilities and granuloma formation by cotton pellet or granuloma pouch. The order of those inhibiting activity was, in general, Dexa greater than MS-1112 greater than Val greater than Hydr. Concomitantly, Xthymolysis and adrenal weight suppression and reduced rate of body weight gain after multiple systemical administration were also observed. Locally administered MS-1112 caused an inhibiting activity, without systemic side-effects. This activity was approximately 3 to 5 times more potent than that of Dexa in rat carrageenin paw edema and cotton pellet granuloma. MS-1112 was less active than Dexa in glycogen liver deposition activity and in the depression of plasma level of corticosterone but more active than Val and Hydr. In the dose administered, MS-1112 had neither androgenic and anabolic nor estrogenic and anti-estrogenic activity. From this data, it concluded that MS-1112 is a very potent agent applicable regarding permeability and retention of steroids in a local site.

Administration, Topical↗
PubMed1975

[Pharmacological study on 9 alpha-fluoro-11 beta, 17,21-trihydroxy-16 beta-methyl pregna-1, 4-diene-3,20-dione-17-benzoate(betamethasone-17-benzoate, MS-1112), a local anti-inflammatory agent. (2). Its action of delayed hypersensitivity dermatitis].

The anti-inflammatory activity of MS-1112, a new steroid compound, after topical application and systemical administration was examined by means of delayed-type hypersensitivity in mice and compared with other glucocorticoid analogues, betamethasone-17-valerate (Val), dexamethasone (Dexa) and betamethasone (Beta). In the case of pretreatment and therapeutic effect, topically applied MS-1112 was most active in inhibiting the delayed-type hypersensitivity induced by picryl chloride. The order of those inhibitory activities of MS-1112 and Val was ointment greater than cream greater than gel. In contrast to MS-1112 and Val, inhibitory action of Dexa was slow in onset after the topical application. It appears that esterification of the 17-hydroxyl group increases the anti-inflammatory activity after topical application. While systemically administered, MS-1112 was more potent than Val, and similarly potent to Beta, but less active than Dexa. From the above results, it may be considered that topically applied MS-1112 is superior to other glucocorticoids in the percutaneous penetration and retention in the skin. MS-1112 is thus considered to be a very potent agent as a dermatocorticoid.

Administration, Topical↗
PubMed1975

Activated guinea-pig C3 and the immune adherence receptor (a complement receptor) on cell membranes.

By treating C3 with purified C1, C4 and C2 in the fluid phase, haemolytically inactive C3 was prepared. This was shown to bind to human erythrocytes by use of radio-labelled (Fab')2 antibody to guinea-pig C3. The activated C3 preparation inhibited immune adherence between EAC43 and human erythrocytes. These findings indicate that the activated C3 attaches to the immune adherence receptor on human erythrocytes. In addition the fluid-phase activated C3 adhered to thymus cells and sheep erythrocytes, whereas EAC43 did not. Thus the immune adherence receptor may be present on so called immune adherence-negative cells, but in insufficient concentration to form rosettes with EAC43.

Animals↗