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Biomedical subjects

M Akao

Publications and source records attributed to M Akao.

At least 73 records · Page 4Linked to original sources
PubMed1990

Inhibitory effect of fumaric acid on hepatocarcinogenesis by thioacetamide in mice.

The inhibitory effect of fumaric acid (FA) on hepatocarcinogenesis was examined in mice fed thioacetamide (TAA). A group of male ICR mice was fed TAA at a level of 0.035% in the diet for 40 weeks and then fed a basal diet for 48 weeks. Hepatic tumors developed in 11 of the 24 animals of this group and they were diagnosed as hepatocellular carcinomas. However, cirrhotic lesions and the enlargement of hepatocyte nucleoli were not as marked in mice as in previous findings in rats fed TAA. The effect of FA on the carcinogenesis was examined in a group of mice fed this compound at a level of 1% in a basal diet after ingestion of TAA. The inhibitory effect of FA on TAA carcinogenesis was so marked that no hepatic carcinomas were found in any of the 15 animals fed FA in combination with TAA.

Animals↗
PubMed1990

Enzymatic and non-enzymatic formation of free radicals from aflatoxin B1.

Formation of free radicals from aflatoxin B1 was demonstrated in systems of a) NADPH/microsome, b) H2O2/peroxidase, c) UV irradiation, d) silver oxide oxidation and e) alkaline dimethyl sulfoxide. In a) to c), radical spots were detected in thin-layer chromatograms. Among several known metabolites of aflatoxin B1, aflatoxin M1 was active in generation of free radical. These results suggest a possible role of free radical metabolites in the cytotoxicity of this hepatocarcinogen.

Aflatoxin B1↗
PubMed1989

Inhibitory effect of fumaric acid on 3'-methyl-4-(dimethylamino)azobenzene-induced hepatocarcinogenesis in rats.

Fumaric acid (FA) suppressed the carcinogenesis in the liver of rats fed 3'-methyl-4-(dimethylamino)azobenzene (3'-Me-DAB), and a study was performed to examine the effect of FA on deoxyribonucleic acid (DNA) synthesis and subcellular structures of hepatocytes under the anticarcinogenic regimens. Male Donryu strain rats were given 3'-Me-DAB by being fed a diet containing 0.06% 3'-Me-DAB for 50 d. They were then given a diet containing 1% FA and drinking water containing 0.025% FA for 53 to 69 weeks. Hepatocytes were isolated from the liver by the collagenase perfusion method and placed in culture, and their activity for DNA synthesis was measured in terms of the incorporation of [3H]dThd into DNA. An enhanced DNA synthesis of hepatocytes was noted in the rats given FA, indicating that FA enhanced the proliferation of hepatocytes to counteract the carcinogenic effect of 3'-Me-DAB. An electron microscopic examination indicated that the distribution of subcellular organella was almost normal in the FA-treated hepatocytes.

Animals↗
PubMed1987

Sintered hydroxyapatite for a percutaneous device and its clinical application.

The sintered hydroxyapatite was designed to be utilized as a percutaneous device. The device was percutaneously fixed through the back skin of mongrel dogs. The tissue reaction around the implants was examined histologically. At 1 month the sintered hydroxyapatite was closely contacted with the skin tissue and downgrowth of epidermis was not observed. The long-term implantation ranging from 3 to 17 months showed that the depth of epidermis downgrowth was limited to only 1 mm. The amino acid composition of fibrous capsule formed around the hydroxyapatite showed close resemblance to vertebrate periosteum. It was confirmed that the sintered hydroxyapatite had good compatibility and long-term stability with skin tissue.

Amino Acids↗
PubMed1987

Inhibitory effect of fumaric acid on hepatocarcinogenesis by thioacetamide in rats.

An inhibitory effect of fumaric acid (FA) on hepatocarcinogenesis was examined in rats fed thioacetamide (TAA). A group of male DONRYU rats were fed TAA at a level of 0.035% in the diet for 40 weeks and then fed a basal diet for 40 weeks. Hepatic carcinomas developed in 9 of 41 animals of this group fed TAA alone. The effect of FA on the carcinogenesis was examined in 2 groups fed both TAA and FA; one group of rats were fed FA at 1% in a basal diet after ingestion of TAA, and another group of rats were fed TAA plus a supplement of 1% FA in the diet. The inhibitory effect of FA on TAA carcinogenesis was so marked that no hepatic carcinomas were found in both groups fed FA in combination with TAA.

Acetamides↗
PubMed1986

Multiple sequences in the Drosophila melanogaster U3 RNA gene are homologous to vertebrate U3 RNA.

We have cloned and sequenced a DNA fragment from the genome of Drosophila melanogaster which is homologous to Novikoff hepatoma (rat) small nucleolar U3 RNA. DNA sequence analysis shows that the regions of homology between the cloned DNA and rat U3 RNA are distributed over the entire length of the molecule and the total homology of linear sequence is 53%. The present finding supports the generalization that U3 RNA has been evolutionally conserved but diverges between mammals and invertebrates. This clone contains the upstream and downstream sequences required for the efficient and correct transcription of small nuclear RNAs. The secondary structure proposed for the U3 RNA sequence deduced from the cloned DNA is similar in general topography to that reported for rat U3 RNA (Bernstein et al., ref. 23).

Animals↗
PubMed1986

Tissue reactions to calcined bone graft.

Calcined bone blocks made by heating raw bovine bone at 1200 degrees C were implanted into defects in canine femoral condyles. X-ray diffraction patterns showed that the calcined bone was well-crystallized hydroxyapatite. Rapid, good new bone growth was observed around the calcined bone which was gradually absorbed along its surface and also by the Haversian canals.

Animals↗
PubMed1986

Fumaric acid enhances DNA synthesis of rat hepatocytes by counteracting the toxicities of mitomycin C and aflatoxin B1.

The effect of fumaric acid was examined on DNA synthesis in hepatocytes or hepatoma cells from rats treated with toxic agents. Male Donryu rats were injected with mitomycin C or aflatoxin B1, singly or in combination with fumaric acid. After a specified period, hepatocytes were isolated from the liver by the collagenase perfusion method and placed in culture, and their activities for DNA synthesis were measured. The iv injection of rats with mitomycin C (0.5 mg/kg) reduced the semiconservative DNA synthesis of the hepatocytes, but simultaneous dosing of fumaric acid (40 mg/kg) enhanced the recovery of the DNA synthesis. The DNA synthesis of hepatoma cells, a 3'-methyl-4-(dimethylamino)azobenzene-induced transplantable cell line growing in the abdominal ascites of rats, was also reduced by the iv injection of mitomycin C but, in contrast to that of the hepatocytes, was little influenced by the simultaneous dosing of fumaric acid. The ip injection of fumaric acid also reduced the toxicity of aflatoxin B1 (0.25 mg/kg, ip), preventing the reduction of DNA synthesis as well as the occurrence of nuclear degenerative changes in the aflatoxin B1-exposed hepatocytes.

Aflatoxin B1↗