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Biomedical subjects

K Takase

Publications and source records attributed to K Takase.

At least 271 records · Page 15Linked to original sources
PubMed1981

Interactions of substrates and alpha-lactalbumin with galactosyltransferase as measured by difference spectroscopy.

The interactions of Mn2+, nucleotides, monosaccharide substrates, and the modifier protein alpha-lactalbumin with galactosyltransferase have been studied by difference spectroscopy. MnCl2, required for significant binding of UDP-galactose or UDP to the enzyme, does not exhibit specific interactions with tyrosine or tryptophan residues. The interaction of UDP-galactose or UDP with galactosyltransferase in 2 mM MnCl2 produces difference spectra with a major positive peak at 284 nm, a second positive peak at 298 nm, and a large negative trough at 254 nm, suggesting the involvement of tyrosine and tryptophan residues in the interaction. The interaction of GlcNAc with the enzyme in 2 mM MnCl2 produces only small nonspecific difference spectra. However, the addition of 100 mM GlcNAc markedly increases the difference extinction coefficient at 284 nm of the UDP-bound enzyme-ligand complex, while the coefficient at 254 nm which arises from UDP remains constant. The results suggest that a conformational change involving tyrosine residues, which does not affect UDP, occurs in the process, enzyme.Mn + UDP + GlcNAc leads to enzyme.Mn.UDP.GlcNAc. Glucose does not show a similar effect. The interaction of galactosyltransferase and alpha-lactalbumin produces difference spectra characteristic of tryptophan and does not affect the difference spectra of galactosyltransferase produced by the interaction with UDP and GlcNAc. This implies that the interaction of the two proteins does not involve the bound UDP on galactosyltransferase and does not affect the conformational change induced by UDP and GlcNAc.

Animals↗
PubMed1981

A study on the relationship between the prognosis of chronic active hepatitis and the HBV associated antigen/antibody systems.

The relationship between the prognosis of the disease based on liver histology and HB virus (HBV) associated antigen/antibody systems was investigated in twenty seven patients with chronic active hepatitis (CAH). These patients were followed up over extended periods with mean duration of 44.3 months. On initial liver biopsy five of twelve patients with CAH with spotty or focal necrosis were HBs antigen (HBsAg) positive, as were also five of six patients with sublobular necrosis and six of nine patients with lobular disorganization. Most of the HBsAg negative patients were anti-HBs or anti-HBc positive: HBV associated antigen or antibody was completely undetectable in only three of the twenty seven patients. There was no difference in the frequency of progression to liver cirrhosis (LC) between the sixteen HBsAg positive and the eleven HBsAg negative patients with CAH. On the other hand, progression to LC occurred in only one of seven HBe antigen (HBeAg) negative patients, compared to four of nine HBeAg positive patients, who were HbsAg positive. There were four patients who were HBeAg positive initially but then became HBeAg negative in the course of observation. LC developed in two of these four patients. These results suggest that in HBsAg positive patients with CAH the presence or absence of HBeAg and the variation in its level can provide useful indicators of the prognosis of the disease.

Adolescent↗
PubMed1980

A sedimentation equilibrium study of the temperature-dependent association of bovine beta-casein.

The temperature-dependent association of beta-casein was studied by the sedimentation equilibrium method. The weight-average molecular weight of the protein was determined in 0.2 M sodium phosphate buffer (pH 6.7) at 20, 15, 10 and 2 degrees C, and was found to be dependent markedly on both temperature and protein concentration. The data were well fitted by a monomer-n-mer association scheme, and the values of n, the second viral coefficient, and the free energy change for the association (association constant) were evaluated. The results show that temperature not only shifts the equilibrium but alters the polymer size: the values of n are 49, 22, and 12 at 20, 15, and 10 degrees C, respectively; the free energy change per monomer becomes more negative with increasing temperature, indicating that the attraction between the monomers in a polymer is stronger at higher temperature. This effect of temperature is in contrast to that of ionic strength which affects mainly the equilibrium. The enthalpy change, entropy change, and heat capacity change for the association were also estimated and were indicative of the formation of a considerable amount of hydrophobic bonds upon association.

Caseins↗
PubMed1979

Structure of beta-casein.

The temperature and concentration dependent association of beta-casein was studied by means of viscometry, gel filtration chromatography, electron microscopy, analytical ultracentrifugation and UV difference spectrophotometry. Degrees of polymerization of 12, 22 and 49 and free energies of association of -21, -23 and -25kJ/mole monomer were found at temperatures of 10, 15 and 20 degrees C respectively in 0.2 M Na phosphate buffer pH 6.7. Monomeric beta-casein was not a completely random coil but became more compact with increasing temperature, due to hydrophobic interactions.

Calorimetry↗
PubMed1979

[Effect of thiol compounds on experimental liver damage (I). Preventive effect of tiopronin (2-mercaptopropionylglycine) on liver damage induced by carbon tetrachloride (author's transl)].

Effects of oral administration of tiopronin (2-mercaptopropionylglycine) on acute liver damage induced in rats by intraperitoneal administration of carbon tetrachloride (CCl4) were investigated. Tiopronin suppressed increase in serum transaminase activity, accumulation of liver triglyceride and decrease of liver glucose-6-phosphatase activity induced by CCl4. CCl4 induced a significant decrease of nonprotein thiol (NPSH) in the liver 24 hr after administration, but this decrease did not result in an increase of nonprotein disulfide in the liver. Tiopronin suppressed the decrease in NPSH induced by CCl4, but did not influence NPSH in normal rats 24 hr after administration. In addition to these biochemical findings, it was also noted that tiopronin prevented necrosis and decrease of glycogen in liver, as determined histologically. Other compounds such as cystamine, cysteine and glutathione proved to have a preventive effect on CCl4-induced liver damage as in the case of tiopronin. It was revealed that such preventive effect correlated to some extent with NPSH content in liver as well as serum transaminase activity and histological findings.

Alanine Transaminase↗
PubMed1975

[Anti-inflammatory action of 2-(2-fluoro-4-biphenylyl) propionic acid (flubiprofen].

2-(2-fluoro-4-biphenylyl) propionic acid (flurbipofen, FP-70), a newly synthesized anti-inflammatory agent, was examined for its effects and then compared with the actions of other standard drugs. Inhibition of capillary permeability in mice: the activity of FP-70 was 7.8 times as potent as ibuprofen (IP), 61 times that of acetylsalicylic acid (AS), 5.7 times that of indomethacin (IM) and 25 times that of phenylbutazone (PB). Inhibition of carrageenin-induced edema in rat paw: the activity of FP-70 was 52 times as potent as IP, 250 times that of potent as AS, 14 times that of potent as IM and 110 times that of potent as PB. Inhibition of heat-induced coagulation of BSA: the activity of FP-70 showed the marked effects much the same as IP. In adrenalectomized rat, FP-70 was also effective. Inhibition of the ultra-violet erythema in guinea-pigs, the activity of FP-70 was 26 times as potent as IP, 790 times that of AS, 25 times that of IM and 68 times that of PB. Regarding the inhibition of CMC induced pouch in rats, the potency of FP-70 was to the same degree as that of predonisolone. In adjuvant induced arthritis in rats, FP-70 reduced and cured inflammatory syndromes and activity was the same or more effective than that of IM. From these results, FP-70 appears to be a most potent nonsteroidal anti-inflammatory agent.

Animals↗