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Biomedical subjects

E Katsura

Publications and source records attributed to E Katsura.

7 recordsLinked to original sources
PubMed1992

Acute toxicity, percutaneous absorption and effects on hepatic mixed function oxidase activities of 2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300) and its chlorinated derivatives.

Acute toxicity of 2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300) (I) and its three chlorinated derivatives, 2',3,4,4'-tetrachloro-2-hydroxydiphenyl ether (II), 2',4,4',5-tetrachloro-2-hydroxydiphenyl ether (III) and 2',3,4,4',5-pentachloro-2-hydroxydiphenyl ether (IV), in mice were examined by intraperitoneal injection. The LD50 values of Irgasan DP300, II, III and IV were 1,090, 710, 650 and 430 mg/kg, respectively. The percutaneous absorptions of these tritiated compounds were also examined by the application on the backs of mice. The radioactivities in most tissues reached to the maximal levels at 12 h or 18 h after dosing, which corresponded to 11-76% of the maximal levels given by the oral administration (Kanetoshi et al. 1988a). These results show the high percutaneous absorbability of Irgasan DP300 and its chlorinated derivatives. The intraperitoneal administrations of III and IV to rats induced hepatic microsomal aminopyrine N-demethylase and aniline 4-hydroxylase activities similarly to phenobarbital. These chlorinated derivatives also increased cytochrome P-450 content, and the activities of aminopyrine N-demethylase and N-methylaniline N-demethylase in hepatic microsomes from mice. The extents of the increases were similar to those by phenobarbital and 3-methylcholanthrene.

Animals↗
PubMed1988

Formation of polychlorinated dibenzo-p-dioxins upon combustion of commercial textile products containing 2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300).

Commercial textile products containing 2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300) as an antimicrobial agent gave dichlorodibenzo-p-dioxin(s) (di-CDD) upon combustion. The extent of conversion of Irgasan DP300 into di-CDD(s) reached 19-43% at 600 degrees C. Upon bleaching the textile products with sodium hypochlorite, Irgasan DP300 was chlorinated to 2',3,4,4'-tetrachloro-2-hydroxydiphenyl ether, 2',4,4',5-tetrachloro-2-hydroxydiphenyl ether and 2',3,4,4',5-pentachloro-2-hydroxydiphenyl ether. These chlorinated derivatives were converted into trichlorodibenzo-p-dioxins and tetrachlorodibenzo-p-dioxin upon combustion, which are more toxic than di-CDD(s). These results suggest that the bleaching and incineration of textile products containing Irgasan DP300 result in environmental pollution by PCDDs.

Dioxins↗
PubMed1987

Chlorination of Irgasan DP300 and formation of dioxins from its chlorinated derivatives.

Irgasan DP300 (2,4,4'-trichloro-2'-hydroxydiphenyl ether) (I), an antimicrobial agent for use with fabrics, was easily chlorinated with sodium hypochlorite to give 2',3,4,4'-tetrachloro-2-hydroxydiphenyl ether (II), 2',4,4',5-tetrachloro-2-hydroxydiphenyl ether (III) and 2',3,4,4',5-pentachloro-2-hydroxydiphenyl ether (IV). Irgasan DP300 and its chlorinated derivatives were readily converted into polychlorinated dibenzo-p-dioxins (PCDDs) by heating: Irgasan DP300 was converted into dichlorodibenzo-p-dioxin(s) (di-CDD, 42%); II into two trichlorodibenzo-p-dioxins (tri-CDDs, 22%) and three tetrachlorodibenzo-p-dioxins (tetra-CDDs, 46%); III into two tri-CDDs (44%), more than two tetra-CDDs (25%) and pentachlorodibenzo-p-dioxin(s) (penta-CDD, 1%); and IV into two tetra-CDDs (16%), trace amounts of penta-CDD(s) and four hexachlorodibenzo-p-dioxins (hexa-CDDs, 40%). Although UV irradiation of Irgasan DP300, II and III gave PCDDs, the amounts of PCDDs formed were much smaller than those obtained by heating. Moreover, PCDD was not detected in the UV irradiation of IV. The identified products suggested that disproportionation of chlorine atom(s) occurred in the photolysis.

Anti-Infective Agents↗
PubMed1978

Chromatium sulfite reductase. I. Characterization of thiosulfate-forming activity at the cell extract level.

Thiosulfate and sulfide were detected in the sulfite reductase reaction catalyzed by a cell-free extract of photoautotrophically grown Chromatium vinosum. Hydrogen was consumed upon addition of sulfite to the extract in the presence of hydrogenase and methylviologen. Hydrogen uptake proceeded biphasically. During the first phase, thiosulfate and sulfide were formed concomitant with the decrease in sulfite. After the disappearance of sulfite, hydrogen was consumed with reduced velocity and sulfide accumulated as the final product with the total consumption of three mol of hydrogen per mol of sulfite. The molecular weight of a major sulfite reductase was estimated to be about 180,000 by the polyacrylamide disc electrophoresis method using enzyme staining. Arsenite. EDTA, alpha,alpha'-dipyridyl, cyanide, or azide did not inhibit the activity at the concentration of 1 mM. The activity was present in the soluble fraction and was stable at --20 degrees C.

2,2'-Dipyridyl↗
PubMed1976

Beriberi.

Explore the source record for details and available documents.

Adult↗
PubMed1975

Thiamine triphosphatase activity of myosin and accelerating effect of thiamine di- and tri-phosphates on superprecipitation of actomyosin.

TTP accelerated ATP-induced superprecipitation of actomyosin in as low a concentration as 30 muM and decreased light scattering by actomyosin. These effects could also be observed in the same way, but to a lesser degree, by addition to TDP. Myosin was able to hydrolyze TTP to TDP, but some important differences were confirmed between myosin TTPase and ATPase. Myosin TTPase was inhibited by actin and showed a much larger Km than that of ATPase. TTP significantly inhibited myosin B ATPase and ATP greatly inhibited myosin B TTPase. These findings suggest that the accelerating effect of TDP and TTP may be due to the binding of thiamine phosphate to the regulatory site of myosin followed by a change in its physical chemical property, rather than due to the competitive binding of thiamine phosphate to the catalytically activity site of myosin.

Actins↗