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Biomedical subjects

A Sakurai

Publications and source records attributed to A Sakurai.

At least 217 records · Page 12Linked to original sources
PubMed1984

Role of first stimulating agents in the production of tumor necrosis factor.

The conditions and kinetics of tumor necrosis factor (TNF) production were examined. For TNF production, dual stimulation is necessary. Priming agents such as BCG, Corynebacterium parvum, and zymosan, which can stimulate the reticuloendothelial system (RES), are good substances for TNF production with the aid of lipopolysaccharide. Wide differences are observed in TNF producibility among different priming agents. The producibility of TNF depends on the degree of stimulation of the RES by the priming agents. Those priming agents, e.g., Propionibacterium acnes and Corynebacterium anaerobium, that are able to induce substantial RES hyperplasia are also able to induce high levels of TNF activity. Following administration of large doses of BCG or zymosan, mice were found to produce TNF activity. However, PPD, OK 432, PSK, and Choreito were unable to induce TNF activity.

Animals↗
PubMed1984

Motility of the anorectum after "rectoplasty with posterior triangular colonic flap" in Hirschsprung's disease.

Clinical assessment of fecal continence and anorectal manometry were carried out in 22 patients with Hirschsprung's disease who had undergone "Rectoplasty with posterior triangular colonic flap". Satisfactory postoperative continence was achieved in 18 out of these 22 patients. The result of anorectal manometry disclosed that normal rectal compliance (reservoir function of the rectum), together with normal resting pressure of the anorectum and rectoanal reflex, is indispensable for an adequate postoperative continence.

Child↗
PubMed1984

Differences in tumour necrosis factor productive ability among rodents.

Large differences in tumour necrosis factor (TNF) productive ability 05337257erved among various strains of mice. DDY, CD-1, ICR and DBA/2 mice could produce a high titre of TNF activity, whereas Balb/c, C3H/HeJms and A/J mice produced a low titre of TNF activity. Administration of 200 micrograms/mouse of LPS to some strains of mice, i.e. DDD and C57B1/6J resulted in good production of TNF. ICR nu/nu mice produced the highest TNF activity among the nude mice. Balb/c nu/nu and DDD nu/nu mice exhibited very low titres of TNF activity. Nude mice required a rather higher dose of the priming agent, Propionibacterium acnes, than heterozygote littermates. Although it is commonly accepted that dual stimulation is necessary for TNF production, TNF activity was detected without the priming agent in SD rats and Golden hamsters by single injection of LPS. In these animals, much higher TNF production was observed after Propionibacterium acnes treatment than after a single injection of LPS. Large differences in TNF productive ability also existed among strains of rats. Although all animals receiving priming agents revealed hyperplasia of reticuloendothelial system, the sensitivity of the animals to LPS is considered to be the most important factor in their TNF productive ability.

Animals↗
PubMed1984

Role of lipid A in the production of tumor necrosis factor and differences in antitumor activity between tumor necrosis factor and lipopolysaccharide.

The role of lipopolysaccharide (LPS) in the production of tumor necrosis factor (TNF) was examined. Alkaline treatment of LPS greatly reduced the TNF-producing activity of LPS, but TNF was produced when a large amount was injected. Free lipid A and lipid A-mouse serum albumin complex, which were prepared from the acid hydrolyzate, effectively induced TNF. However, the polysaccharide-rich fraction of the acid hydrolyzate was not capable of inducing TNF. Preincubation of LPS with polymixin B largely abrogated the TNF-producing activity of LPS. The differences in antitumor activity between TNF and LPS were also tested. TNF has a direct cytotoxicity against cancer cells in vitro but LPS does not. The activity of TNF was not inhibited by preincubation with polymixin B. Tumor necrosis in vivo was inhibited by preincubation of LPS with polymixin B but not by that of TNF. Galactosamine was found to induce susceptibility to the lethal effects of LPS, but did not influence the action of TNF. Lipid A is largely responsible for the TNF-inducing activity of LPS, but is not essential for the antitumor activity of TNF.

Animals↗
PubMed1984

[Antitumor activity of tumor necrosis factor (TNF) in vitro and in vivo].

The antitumor activity of highly purified tumor necrosis factor (TNF) was tested. TNF had direct cytotoxic activity on all cancer cells examined in vitro, and no species specificity. Normal cells showed no damage on addition of TNF. TNF showed excellent curative effects against all types of murine and human tumors tested in vivo. A great difference in curative effects of TNF was observed between Meth A sarcoma transplanted into Balb/c nu/+ and Balb/c nu/nu mice with a single intravenous administration. This experiment suggested that in addition to direct cytotoxicity against tumor cells, TNF-induced host-mediated factor which contributed to the antitumor effects Murine TNF has on inhibitory effect against multiple pulmonary metastasis of Lewis Lung-tumor. Very few references to this field could be found in the literature and the present paper mainly presented our own research.

Animals↗
PubMed1980

In-beam electron impact mass spectrometry of N-carbobenzoxy derivatives of oligopeptides composed of leucine and isoleucine.

The characteristics of the in-beam electron impact mass spectra of 13 N-carbobenzoxyoligopeptides (up to pentapeptides) composed mainly of leucine and isoleucine, and their alkyl and N-hydroxysuccinimide esters are described. In the cases of di- and tripeptide derivatives, each in-beam electron impact spectrum exhibited an abundant [M + 1]+ peak as well as amino-acyl fragments. However, in the case of pentapeptides the in-beam spectra measured under the routine conditions corresponded to the conventional electron impact spectra of the cyclopeptide derivatives formed by thermal cyclization in the mass spectrometer and few [M + 1]+ ions of the original peptides were observed. From the studies on temperature spectral change of in-beam electron impact spectra it became clear that rapid heating of the sample over the temperature range 200-300 degrees C gave abundant [M + 1]+ ions as well as fragment ions originating from the thermally intact peptide as the major peaks in the spectrum.

Isoleucine↗
PubMed1977

Synthetic identification as a hexapeptide of alpha substance-IB inducing sexual agglutination in Saccharomyces cerevisiae.

For the identification of a peptidyl principle inducing sexual agglutination in the yeast, 2 supposed hexapeptides (1a, b) were synthesized by the conventional method. The 1a (H-Arg-Gly-Pro-Phe-Pro-Ile-OH) revealed complete identity with the natural peptide in TLC, MS and biological property on agglutination. The 1b showed the sexual agglutinability in the same degree as 1a, though distinct differences were observed in the chemical data. Both 1a and 1b had a strong bitter taste.

Agglutination↗
PubMed1976

Mating reaction in Saccharomyces cerevisiae. IX. Regulation of sexual cell agglutinability of a type cells by a sex factor produced by alpha type cells.

A diffusible sex-specific substance called alpha substance-I (alphaS-I) was isolated from culture filtrate of alpha type strains of the yeast Saccharomyces cerevisiae. The isolated alphaS-I, an oligopeptide, induced sexual cell agglutinability in inducible alpha type strains and enhanced the agglutinability in constitutive a type strains. The induction of sexual agglutinability was detected in 30 min and reached maximum in 90 min, when 0.2 mug/ml of alphaS-I was added to inducible a type cells. The a type-specific factor responsible for sexual cell agglutination, called a type agglutination factor (aAF), was shown to be produced during the induction or the enhancement of agglutinability of a type cells by alphaS-I. The aAF produced in response to alphaS-I was not different in the susceptibility to proteolytic enzymes and disulfide-cleaving agents from those produced constitutively in the absence of alphaS-I.

Agglutination↗