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Biomedical subjects

A Yuasa

Publications and source records attributed to A Yuasa.

At least 55 records · Page 3Linked to original sources
PubMed1990

Relationship between liver degeneration and the production of dark firm dry meat in slaughtered pigs.

Sixty-five of 77 slaughtered pigs with liver degeneration produced dark firm dry (DFD) meat. The biochemical properties of blood, liver and muscle of those pigs were examined. In the blood, the NEFA level was higher, which indicated the mobilization of lipids from adipose tissues. The serum CPK and LDH5 levels were higher, the enzymes being derived from muscle. In the degenerative liver with yellowish discoloration, the TG level was higher and the glycogen level was lower than in a normal liver. In the DFD muscle with the final pH above 6.0, both the glycogen level immediately after slaughter and the lactic acid level 24 hr after slaughter were lower than in a normal muscle with the final pH below 6.0. Five pigs exhausted experimentally by 53-hr fasting and hard exercise showed the same changes in the blood and liver as the pigs with liver degeneration. Four of the 5 exhausted pigs showed the same changes in the muscle as in DFD meat. From these data, it was confirmed that exhaustion before slaughter led to lipid accumulation in the liver and to a decrease in muscle glycogen, and consequently caused both liver degeneration and DFD meat in the same pig.

Alanine Transaminase↗
PubMed1990

[A study on tolerance to denopamine, oral beta 1-agonist].

To investigate whether effects of denopamine become weaker or not. Initial single dose (10 mg) effects, single dose effects after long-term treatment (30 mg per day, about 40 days), and chronic effects were studied by Doppler and echocardiography in 23 patients with heart failure (NYHA II-III). 1) Chronic effects: Blood pressure and heart rates didn't change significantly whether they were measured before or after long-term treatment. But left ventricular end-diastolic dimension decreased from 54.6 +/- 10.2 to 53.3 +/- 10.1 mm (p less than 0.01). Percent fractional shortening (%FS) increased from 22.6 +/- 7.8 to 25.3 +/- 8.6% (p less than 0.05). Mean velocity of circumferential fiber shortening (mVCF) tended to increase, and cardiac index (CI) increased from 2.71 +/- 0.47 to 2.98 +/- 0.57 l/min/m2 (p less than 0.01). 2) Initial single dose effects: Blood pressure and heart rates increased significantly. %FS increased from 25.0 +/- 7.7 to 25.9 +/- 7.8% (p less than 0.05), mVCF increased from 0.94 +/- 0.26 to 1.03 +/- 0.28 cir/sec (p less than 0.01), and CI increased from 2.81 +/- 0.49 to 3.09 +/- 0.49 l/min/m2 (p less than 0.01). 3) Single dose effects after long-term treatment: Blood pressure and heart rates increased significantly. %FS tended to increase, mVCF increased from 1.02 +/- 0.27 to 1.09 +/- 0.30 cir/sec (p less than 0.05), and CI increased from 3.05 +/- 0.62 to 3.37 +/- 0.54 l/min/m2 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1989

Purification and properties of cytochrome P-450 generally acting as a catalyst on benzo[a]pyrene hydroxylation from liver microsomes of untreated rats.

A form of cytochrome P-450 generally catalyzing benzo[a]pyrene (B[a]P) hydroxylation was purified from liver microsomes of untreated rats on the basis of the catalytic activity. The purification procedures consisted of cholate solubilization and chromatography in 3 steps, on DEAE-Toyopearl (at room temperature), hydroxylapatite, and CM-Toyopearl columns. Cytochrome P-450 purified in this way (named P-450/B[a]P) was homogeneous on SDS-polyacrylamide gel electrophoresis, and the molecular weight was estimated to be 51,000. The absorption spectra of the oxidized form of P-450/B[a]P showed a Soret peak at 417 nm, characteristic of low-spin hemoprotein, and the Soret peak of the reduced cytochrome P-450-CO complex was at 451 nm. Immunochemical analysis of P-450/B[a]P indicated that P-450/B[a]P is immunologically distinct from P-450b (a major phenobarbital-inducible form of P-450) and P-450c (a major 3-methylcholanthrene-inducible form of P-450, which highly catalyzes the hydroxylation of B[a]P). B[a]P hydroxylase activity in liver microsomes of untreated rats was inhibited to about 20% by the P-450/B[a]P antibody. These results demonstrate that P-450/B[a]P is a different form of P-450 from P-450b and P-450c, and generally catalyzes B[a]P hydroxylation in liver microsomes of untreated rats.

Amino Acid Sequence↗
PubMed1989

Purification and properties of UDP-glucuronyltransferase from kidney microsomes of beta-naphthoflavone-treated rat.

Rat kidney microsomal UDP-glucuronyltransferase activities toward phenoic xenobiotics were enhanced about 4-5-fold by treatment of the animal with beta-naphthoflavone. The transferase activity toward serotonin, an endogenous substrate, was also enhanced about 7.5-fold. A form of UDP-glucuronyltransferase was purified from kidney microsomes of beta-naphthoflavone-treated rat by solubilization with sodium cholate and two steps of column chromatography, the first with DEAE-Toyopearl (fast flow rate liquid chromatography:FFLC) and the second with UDP-hexanolamine Sepharose 4B (affinity chromatography). These procedures gave about 39-fold purification and 11.5% yield of the transferase activity toward 1-naphthol. The preparation, tentatively termed "GT-2," was highly purified as judged from the single protein band (Mr 54,000) on sodium dodecylsulfate (SDS)-polyacrylamide slab gel electrophoresis. It catalyzed the glucuronidation of not only phenolic xenobiotics such as 1-naphthol, 4-nitrophenol, and 4-methylumbelliferone but also serotonin. From the result that apparent molecular weight of GT-2 was reduced to 50,000 by endo-beta-N-acetylglucosaminidase H (Endo H)-treatment, GT-2 was found to be a 50,000 Da polypeptide carrying "high mannose" type oligosaccharide chain(s). The NH2-terminal sequence of 20 residues of GT-2 was determined to be Asp-Lys-Leu-Leu-Val-Val-Pro-Gln-Asp-Gly-Ser-His-Trp-Leu-Ser-Met-Lys-Glu- Ile-Val . It was observed that there are two amino acids substitutions in the seven NH2-terminal residues in comparison with GT-1, which was purified from liver microsomes of 3-methylcholanthrene-treated rat. The NH2-terminal sequence of GT-2 was found to be homologous with the NH2-terminal sequence from the 26th to 46th amino acid residue of various UDP-glucuronyltransferase cloned by other investigators.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗
PubMed1989

Production of dark firm dry meat in slaughtered pigs with so-called liver degeneration characterized by yellowish discoloration and high lipid contents.

The livers which are discolored yellowish and have a large amount of lipids (liver degeneration) are frequently observed in slaughtered pigs. Dark firm dry (DFD) meat and liver degeneration have a common etiological agent of exhaustion in pigs before slaughter. The correlation between them was examined. In 65 cases of 77 slaughtered pigs with the degenerative liver, which contained more than 6.6% total lipids of liver wet weight, the carcasses showed early rigor mortis and the higher final pH above 6.0. R values of the muscles, which indicated the decrease of ATP, were higher. The meat had a DFD appearance and the muscle fibers had no tendency to shrink. These data showed that the pigs with liver degeneration produced DFD meat at a high rate. In 4 cases of 5 pigs exhausted experimentally by 53 hr fasting and hard exercise before slaughter, both liver degeneration and DFD meat were produced simultaneously. The livers of them were discolored and contained about 8.0% or more total lipids. The carcasses of them showed early rigor mortis and the higher final pH above 6.0. From these data, it was suggested that the exhaustion in pigs before slaughter caused both liver degeneration and DFD meat.

Animals↗
PubMed1988

Enhancement of UDP-glucuronyltransferase, UDP-glucose dehydrogenase, and glutathione S-transferase activities in rat liver by dietary administration of eugenol.

Male Fisher rats were fed a diet ad lib. containing eugenol (4-allyl-2-methoxyphenol) to observe its effects on liver drug-detoxifying enzymes such as UDP-glucuronyltransferase (GT), UDP-glucose dehydrogenase (DH) and glutathione S-transferase (GST). Liver weights were not affected significantly by a diet containing 3% eugenol (w/w) for 13 weeks. The activities of GT of liver microsomes toward various xenobiotic substances such as 4-nitrophenol, 1-naphthol, 4-hydroxybiphenyl and 4-methylumbelliferone were enhanced by dietary administration of eugenol, but the activity of GT toward its endogenous substrate, bilirubin, was not changed. Dose-response relationships between the enhancement of GT activities toward these xenobiotics and the dose of eugenol were observed. The induced higher activities of GT toward these xenobiotics were maintained during 13 weeks of eugenol treatment. Similar results on DH and GST activities in the liver cytosol were obtained by dietary administration of eugenol, while no effect on cytochrome P-450 content in the liver microsomes from the rats fed the eugenol diet was observed during 13 weeks. These results suggest that the intracellular content of the active intermediates of various drugs or carcinogens would be reduced by this specific enhancement of drug-detoxifying enzymes in the liver of rats given a diet containing eugenol, as previously described for a diet containing 2(3)-tert-butyl-4-hydroxyanisole (BHA) [Y-N. Cha and H. S. Heine, Cancer Res. 42, 2609 (1982)].

Animals↗
PubMed1988

Purification and properties of 5-hydroxytryptamine UDP-glucuronyltransferase from rat liver microsomes.

5-Hydroxytryptamine UDP-glucuronyltransferase was highly purified from untreated rat liver microsomes. The specific activity towards 5-hydroxytryptamine was increased 178-fold over the starting solubilized microsomes with a final yield of 3%. The final preparation contained two major and one minor Coomassie brilliant blue staining polypeptide bands visible after SDS-polyacrylamide gel electrophoresis. One of the major bands was identified as 3-methylcholanthrene-inducible UDP-glucuronyltransferase, so the other (molecular weight of 55,500) appeared to be 5-hydroxytryptamine UDP-glucuronyltransferase. Concanavalin A reacted with the 55,500-dalton polypeptide. Phospholipid was indispensable for the enzyme activity. The enzyme activity in the final preparation was activated by divalent cations. Simple Michaelis-Menten kinetics were followed with respect to 5-hydroxytryptamine, but deviations from this kinetics were observed with respect to UDP-glucuronic acid and Mg2+. As regards Mg2+ stimulation, further experiments indicated that the added Mg2+ was non-competitive with 5-hydroxytryptamine, but at low concentrations of Mg2+ it was competitive with UDP-glucuronic acid and at high concentrations of Mg2+ it was non-competitive with UDP-glucuronic acid. The final preparation showed high substrate specificity towards 5-hydroxytryptamine among endogenous substrates tested. From these results, it was concluded that the enzyme described here is a new form of UDP-glucuronyltransferase isozyme, and its activity showed a peculiar dependence on Mg2+.

Animals↗
PubMed1988

Purification and properties of a form of UDP-glucuronyltransferase from liver microsomes of 3-methylcholanthrene-treated rats.

A form of UDP-glucuronyltransferase has been purified from liver microsomes of 3-methylcholanthrene-treated rats by a simple and rapid method involving chromatography on DEAE-Toyopearl and UDP-hexanolamine Sepharose columns. The purified preparation gave a single protein band (Mr 54,000) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It catalyzed the glucuronidation of not only phenolic xenobiotics such as 4-nitrophenol, 1-naphthol, and eugenol but also serotonin, which is an endogenous compound. Its activities toward 4-hydroxybiphenyl and testosterone were very low and no activity was detected toward bilirubin. After removal of the detergent (Emulgen 911), the transferase activity was stimulated by various phospholipids, about 10-fold activation being attained with phosphatidylcholine and lysophosphatidylcholine. On nitrocellulose sheets concanavalin A, but not wheat germ agglutinin, bound to the purified transferase, and this binding was abolished in the presence of alpha-methylmannoside and after treatment of the enzyme with endo-beta-N-acetylglucosaminidase H (Endo H). These observations provided evidence that the transferase is a glycoprotein carrying a "high mannose type" of oligosaccharide chain(s). The NH2-terminal 7 residues of the purified enzyme were determined to be Thr-Lys-Leu-Leu-Val-Trp-Pro.

Animals↗
PubMed1988

Electrophysiological effects of propranolol in patients with sinus node dysfunction.

The electrophysiological effects of intravenous propranolol (0.15 mg/kg) were studied in 26 patients with sinus node dysfunction (SND group) and 9 patients with normal sinus node function (control group). Spontaneous cycle length and AH interval were significantly increased in the control and SND groups after propranolol. PA and HV intervals, calculated sinoatrial conduction time and refractory periods of the atrium, AV node and ventricle were not significantly changed in either group. Maximum corrected sinus node recovery time (max CSRT) was not changed in the control group, but it was significantly prolonged in the SND group. These results of the overdrive suppression test were in disagreement with those of previous studies. Propranolol lengthened spontaneous cycle length (by more than 200 msec) and/or max CSRT (by more than 1000 msec) in 8 of 26 patients with SND. Thus, it is suggested that propranolol should be used with caution in patients with SND.

Arrhythmia, Sinus↗
PubMed1986

Suppressed mutagenicity of benzo[a]pyrene by the liver S9 fraction and microsomes from eugenol-treated rats.

The mutagenicity of benzo[a]pyrene (B[a]P) in the Ames test using liver S9 fraction prepared from rats pretreated with eugenol (4-allyl-2-methoxyphenol) was suppressed to a lower level than that obtained using liver S9 from untreated rats. There was a reverse correlation between the mutagenicity of B[a]P and the dose of eugenol administered to the animals. Similarly suppressed mutagenicity was observed when liver microsomes, instead of the S9 fraction, were used in the Ames test. The mutagenic activity of B[a]P and arylhydrocarbon hydroxylase (AHH) could not be inhibited by the direct addition of eugenol into the assay mixtures. In eugenol-treated microsomes, cytochrome P-450 content, AHH activity and total B[a]P hydroxylase activity were decreased to 81, 29 and 48% of the control values, respectively. The mutagenicity of B[a]P catalyzed by microsomes from rats fed ad libitum on a diet containing 5% eugenol in the Ames test was significantly decreased. AHH activity and total B[a]P hydroxylase activity were also decreased in these liver microsomes. These results indicate that the activation of B[a]P in rat liver by cytochrome P-450, which metabolizes B[a]P to ultimate mutagens or carcinogens, is reduced by the administration of eugenol.

Administration, Oral↗