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F Imai

Publications and source records attributed to F Imai.

At least 55 records · Page 3Linked to original sources
PubMed1981

Immunological characterization of gamma-glutamyltransferases in human serum.

The immunological properties of gamma-glutamyltransferases (gamma-GTs) from human serum, liver and tonsil were studied by using a monospecific antibody to human kidney gamma-GT for the purpose of elucidating their isozymic relationships. gamma-GTs partially purified from liver and tonsil were indistinguishable in this respect from kidney gamma-GT. gamma-GT in sera from patients with hepato-biliary diseases, on the other hand, was heterogeneous in molecular size as revealed by sucrose density gradient centrifugation and Sephadex G-150 gel filtration, and was inhibited and precipitated by the above antibody relatively poorly as compared with the kidney enzyme. When these sera were treated with bromelain, however, the molecular size of gamma-GT was reduced and the enzyme now reacted with the antibody as strongly as kidney gamma-GT. gamma-GT from bromelain-treated sera also exhibited a single immunoprecipitin line smoothly fusible with that from kidney gamma-GT; the enzyme-antibody complex still exhibited gamma-GT activity. The major form of gamma-GT partially purified from papain-treated sera, even though indistinguishable from kidney gamma-GT immunologically and in molecular size, exhibited a mobility on polyacrylamide gel electrophoresis which was higher than that of kidney gamma-GT but similar to that of liver gamma-GT. It is suggested that gamma-GT in human sera is heterogeneous in molecular size and electric charge but is composed of common peptide chains, probably identical to those of kidney gamma-GT.

Antibodies↗
PubMed1981

Enzyme deviation patterns in primary rat hepatomas induced by sequential administration of two chemically different carcinogens.

Enzyme deviation patterns were examined in primary rat hepatomas induced by short-term sequential administration of two chemical carcinogens from among 2-fluorenylacetamide (FAA), diethylnitrosamine (DENA), and 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) or by FAA or 3'-Me-DAB followed by phenobarbital as a promoter. The purpose was to discern how the patterns are influenced by different administration schedules of carcinogens and which of the two carcinogens in the sequence affects the pattern more. Biochemical differentiation of hyperplastic hepatic nodules and hepatomas was determined by simultaneous assays of activities and isozyme composition of glucose-adenosine triphosphate phosphotransferase, pyruvate kinase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, and gamma-glutamyltransferase with consideration of histological classification of nodules and tumors. Poorly differentiated hepatomas were predominantly induced by 3'-Me-DAB followed by FAA or DENA except for hepatomas induced by 3'-Me-DAB followed by phenobarbital, which were mainly well and moderately differentiated; well and moderately differentiated hepatomas were predominantly induced by FAA followed by 3'-Me-DAB or phenobarbital. The degree of enzyme deviation of the hepatomas induced by DENA as the first carcinogen was intermediate between those of hepatomas induced by FAA or 3'-Me-DAB, although the degree tended to increase with increased dose or term of DENA. These results indicate that deviations of some enzymes, such as pyruvate kinase and fructose-1,6-bisphosphatase, as well as histological differentiation of the primary hepatomas are more strongly influenced by the first carcinogen than by the second under our administration schedules and that the degree of enzyme deviation shown by hepatomas produced by a particular carcinogen treatment regimen principally related to the potential of that regimen to induce the more anaplastic tumors.

2-Acetylaminofluorene↗
PubMed1980

Re-elevation of gamma-glutamyl transpeptidase activity in periportal hepatocytes of rats with age.

Changes in the level of gamma-glutamyl transpeptidase (gamma-GTP) in the rat liver with age were studied histochemically and biochemically. A high enzyme activity was seen throughout the hepatic lobule with some predominance in the periportal area in the neonatal rat liver. This enzyme activity disappeared almost completely from the hepatocytes of young adults. However, after 30 weeks of age, there was a gradual re-elevation of the enzyme activity in the periportal hepatocytes, attaining a level similar to that of neonatal liver. Expression of gamma-GTP activity in the rat hepatocytes is associated with not only onconeonatal events but also aging.

Aging↗
PubMed1979

Rat hyperplastic hepatic nodules and primary hepatomas retaining abnormally high pyruvate kinase L type activity.

As reported in our previous paper (Sato et al., Cancer Res., 38: 3086-3093, 1978), most of the hyperplastic hepatic nodules and primary hepatomas induced by N-2-fluorenylacetamide (2-FAA), diethylnitrosamine (DENA), and 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) showed that pyruvate kinase liver (L) type decreases and the prototypic M2 type increases concomitantly with dedifferentiation of tissues. However, at least 14 samples among 120, mostly hyperplastic nodules and highly differentiated hepatomas induced by 2-FAA or DENA, retained exceptionally high activities of the L type, while other enzymes of carbohydrate metabolism in these tissues deviated toward a common pattern similar to that in the fetal liver. Individual patterns of 9 enzymes including pyruvate kinase of carbohydrate metabolism in these samples are arranged and discussed as examples of unbalanced enzyme deviation in hepatocarcinogenesis.

Animals↗
PubMed1977

Enzyme alteration in skeletal muscle of mice with muscular dystrophy.

1. Developmental enzyme alterations were investigated in skeletal muscle of the hereditary progressive muscular dystrophy (PMD) mice of C57BL/6J strain. 2. Enzymes examined were classified into three groups according to changes of activities in dystrophy muscle during ageing. Activities of creatine kinase (EC 2.7.3.2), pyruvate kinase (EC 2.7.1.40), glycogen phosphorylase (EC 2.4.1.1), and fructose-biphosphate aldolase (EC 4.1.2.13), each of which had the respective muscle specific isoenzyme of extremely high activity in normal adult skeletal muscle, decreased rapidly in dystrophy muscle from the early stage of the disease with ageing. Activities of glycogen synthase (EC 2.4.1.11) and hexokinase (EC 2.7.1.1) were higher in dystrophy muscle in the early stage but decreased gradually to lower levels than those in the control with ageing. Activities of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) were always much higher in dystrophy muscle than in the control, with no relation to ageing. 3. Isoenzymes of creatine kinase, pyruvate kinase and phosphorylase in dystrophy muscle were mainly the muscle types, indicating that muscle differentiation was not blocked profoundly even in dystrophy muscle. In limited cases, especially in the early stage of the disease, very weak activities of the non-muscle fetal type isoenzymes of creatine kinase and phosphorylase were detected, apparently associated with partial muscle regeneration in dystrophy muscle.

Aging↗
PubMed1976

Isozyme patterns of glycogen phosphorylase in rat tissues and transplantable hepatomas.

Isozyme patterns of glycogen phosphorylase in the Morris and Yoshida hepatomas were compared electrophoretically and immunochemically with those in rat tissues during development. A 3rd phosphorylase isozyme, observed previously in hepatomas and fetal tissues by isoelectric focusing and by immunochemical titration, was also separated by polyacrylamide disc gel electrophoresis. It was observed commonly in various rat hepatomas, together with variable activities of the liver type, depending on the degree of differentiation. This isozyme is nearly the sole type in placenta and early embryo, and in liver and skeletal muscle it is replaced during fetal development with the organ-specific liver and muscle type. In adult rat brain the fetal type is retained at low levels, together with the muscle type. In kidney, spleen, testis, uterus, lung, and stomach, the fetal type is present together with the liver type. This isozyme in hepatomas and adult brain is identical with the fetal-type, as determined by Ouchterlony double diffusion and activity inhibition tests. Thus, it is considered to be a prototype whose appearance in hepatomas is one of many known examples of fetal protein expression in cancer. In some poorly differentiated hepatomas, the liver-type isozyme migrated slightly more slowly in polyacrylamide gel but could not be distinguished from the liver isozyme immunochemically.

Animals↗