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Biomedical subjects

S Sakai

Publications and source records attributed to S Sakai.

At least 739 records · Page 41Linked to original sources
PubMed1977

Degradation of the plant flavonoid phellamurin by Aspergillus niger.

We have previously described the structure of phellamurin, a plant flavonoid, as 3,4',5,7-tetrahydroxy-8-isoprenylflavanone-7-O-glucoside (17). Degradation of phellamurin by Aspergillus niger using modified Czapek-Dox medium as well as phellamurin or one of its degradation products as a sole carbon source, is reported here. Eleven compounds are identified from phellamurin degradation products. A. niger apparently decomposes phellamurin by first removing glucose with beta-glucosidase; neophellamuretin is the first degradation product. Fission of the heterocyclic ring of (5''-hydroxyisopropyl-4'',5''-dihydrofurano)[2'',3''-h]3,4',5-trihydroxyflavanone, which is obtained from neophellamuretin through a few alterations of the side chain, is followed by cleavage of a C--C bond between C=O and carbon at alpha-position and conversion of (5''-hydroxyisopropyl-4'',5''-dihydrofurano)[2'',3''-d]-2',4,6',alpha-tetrahydroxychalcone to rho-hydroxymandelic acid (B-ring) and 2,4,6-trihydroxy-5-carboxyphenylacetic acid (A-ring). It is suggested that rho-hydroxymandelic acid is oxidized to rho-hydroxybenzoic acid. 2,4,6-Trihydroxy-5-carboxyphenylacetic acid is metabolized to phloroglucinol carboxylic acid, which subsequently is decarboxylated to phloroglucinol. These results provided new information on the isoprene unit metabolism of the side chain of phellamurin and firmly established the degradation pathway of phellamurin by A. niger.

Aspergillus niger↗
PubMed1977

Relaxant effect of aspirin-like drugs on isolated guinea pig tracheal chain.

The interrelation of the inhibitory effect of aspirin-like drugs on the resting tonus of tracheal chain in guinea pigs, arachidonic acid-induced contraction in rat stomach fundus strips and bradykinin-induced bronchoconstriction in guinea pigs in vivo was investigated. All the drugs tested produced a dose-related inhibitory action on the resting tonus of the tracheal chain in comparatively low doses. Diclofenac was the most potent of all the drugs and was equal in activity to isoproterenol, followed in descending order by flufenamic acid, mefenamic acid, indomethacin, ibuprofen, phenylbutazone, oxyphenbutazone and aspirin. These aspirin-like drugs also inhibited arachidonic acid-induced contraction in rat stomach fundus strips. A highly significant correlation was observed between the potency of inhibition of the arachidonic acid-induced contraction and the relaxant effect on the tracheal chain. Moreover, the drugs antagonized bradykinin-induced bronchoconstriction in guinea pigs in vivo and the order of potency roughly paralleled that of the tracheal chain. These results suggest that the aspirin-like drugs produce a reduction in resting tonus of the isolated guinea pig tracheal chain by inhibition of intramural biosynthesis of prostaglandin endoperoxides.

Animals↗
PubMed1976

Five cases of tick bite.

Reported here are five cases of tick bite: in a 2-year-old boy, a 3-year-old girl, a 72-year-old woman, a 29-year-old woman, and a 51-year-old man. Four cases are thought to have occurred in a mountain area while one occurred in a city garden. None were accompanied with severe systemic symptoms or deuteropathies. The parasites were identified as the adult female tick Ixodes ovatus Neumann (3 cases) and Ixodes nipponensis Kitaoka et Saito (2 cases), which are commonly distributed in Japan.

Adult↗
PubMed1976

Binding of mouse choriomammotropin to prolactin receptors in the mouse mammary gland.

The interaction between mouse choriomammotropin and mouse mammary glands was examined by radioreceptor assays using ovine prolactin (NIH-P-S9) iodinated by lactoperoxidase as a tracer. Mouse pituitary extracts and placental extracts were subjected to 10% acrylamide gel electrophoresis. Gels were cut into 2-mm segments after electrophoresis, and stored in 1 ml 0.05 M phosphate buffer (pH 7.4) containing 0.05 M NaCl overnight for elution. Lactating mammary tissues from D strain mice were incubated for 120 min in 1 ml Medium 199 containing 6 ng of 125I-prolactin and 0.1 ml of each eluate. Pituitary extracts displaced 125I-prolactin only at the position which coincides with the prolactin band. Displacement was observed at two positions of the gel when placental extracts were used. Relative mobilities (Rm) were 0.21 and 0.71, respectively. The slowly migrating component of choriomammotropin inhibited the binding of 125-I-prolactin more strongly that the rapidly migrating one. Neither of them was identified as a distinct band in stained gels. The molecular weight of ovine prolactin, mouse pituitary prolactin and the slowly migrating component of mouse choriomammotropin was estimated to be 23000 using disc electrophoresis but the ion charges of these hormones were considerably different.

Animals↗
PubMed1976

Studies on the properties of a streptococcal preparation OK-432 (NSC-B116209) as an immunopotentiator. I. Activation of serum complement components and peritoneal exudate cells by group A streptococcus.

The inhibition of transplanted tumors in animals, which were previously injected with a streptococcal preparation, OK-432, has been suggestible to be induced by direct or host mediated effects. In this paper, it was examined of immunopotentiating ability of Group A streptococcus (Su-strain), which is a active component of OK-432, with respects to reticuloendotherial system and serum complement components. Human fresh serum incubated with the heated streptococcus (HSu-coccus) was analyzed by means of immunoelectrophoresis. Activated component of C3 proactivator was observed in gamma region as immunoprecipitin line developed by rabbit anti human C3 proactivator serum, and conversion of C3 component (beta1C) to beta1A was observed in alpha region by rabbit anti human beta1C/beta1A serum. The activation of serum complement components might be occurred via alternate pathway, because EDTA inhibited the activation but EGTA did not. Meanwhile, the peritoneal exudate cells from mice injected intraperitoneally with HSu-coccus were examined with respects to cell population and their antitumor effect. On the 7th day after injection of HSu-coccus, about 90% of the peritoneal cells was lymphocytes, and 70% of these lymphocytes was susceptible to rabbit anti mouse thymus cell serum or to AKR anti thetaC3H serum. When L1210 leukemia cells preincubated with these peritoneal cells were inoculated intraperitoneally into BALB/c mice, the leukemic cells could not allowed the growth, resulting in prolongation of life-span of the experimental animals. These results suggested that nonspecific effector activity of T-derived lymphocyte induced by HSu-coccus could be one of the factors participating in antitumor activity of OK-432. Additionally, the results obtained with OK-432 were most the same as those with HSu-coccus in these respects. Further, the relation between the stimulation of leucocytes and activation of complement components was discussed.

Animals↗
PubMed1975

A receptor site for prolactin in lactating mouse mammary tissues.

Prolactin iodinated by lactoperoxidase method showed immunologically, electrophoretically and biolo9gically similar properties to native prolactin and possessed enough specific radioactivity for receptor studies. 1251-prolactin was incubated with mouse mammary tissues at 8 days of lactation. Both binding and release of 1251-prolactin depended on incubation time and temperature and were maximal at 37 degrees C. Michaelis constant was estimated to be 1.4 X 10(-9) M from Lineweaver-Burk plot and to be 1.2 X 10(-9) M from id-value of the dose-response curve for displacement with native prolactin. Total number of binding sites for prolactin was 1.38 X 10(-15) mole per mg weight of tissue. Ovine prolactin, human growth hormone and human placental lactogen complete with 1251-prolactin and dose-response curves for these three hormones were all parallel. These results suggest the existence of a specific receptor site with high affinity for prolactin in lactating mouse mammary glands.

Animals↗
PubMed1975

Experimental diarrhea in cynomolgus monkeys by oral administration with Clostridium perfringens type A viable cells or enterotoxin.

Purified C. perfringens type A enterotoxin fed orally in an amount of 5 mg caused both vomiting and diarrhea in the monkey only when the gastric juice had been neutralized. Exposure of enterotoxin to pH 4.0 or below rapidly destroyed the activity. All three monkeys receiving sodium bicarbonate and 2.4 X 10(10) viable cells grown in DS medium developed diarrhea, and only one of them vomited once. The diarrhea lasted for 13, 18 and 19 hr. The symptoms were similar to those reported in human cases of C. perfringens food poisoning. These results have verified the general notion that C. perfringens food poisoning should be categorized as a true "intravital intoxication". The reversed passive hemagglutination test detected enterotoxin directly in most fecal samples. This method may be applicable for diagnosis of human cases of C. perfringens food poisoning. Neither enterotoxin nor anti-enterotoxin was detected in serum samples taken from any monkey up to 21 days after the challenge. We are tempted to conclude, therefore, that no significant amount of C. perfringens enterotoxin is absorbed from the intestine.

Administration, Oral↗