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Biomedical subjects

T Harada

Publications and source records attributed to T Harada.

At least 1,207 records · Page 67Linked to original sources
PubMed1977

Enhancing effect of thoracotomy and/or laparotomy on the growth of ascitic tumor in rats.

To evaluate the effect of operative stress on a tumor growth, thoracotomy and/or laparotomy were performed 48 hours after the intraperitoneal inoculation of Sato lung cancer cells in Donryu rats. The survival time and the spread of the tumor were examined. Thoracotomy and laparothoracotomy reduced significantly the survival time of the inoculated rats as compared with the control but no significant difference was observed between the two test groups subjected to operative stress. No difference was observed in the spread of the tumor between the test groups and the control. These results indicated that the operative stress increased only the number of metastatic foci and did not change the characteristics of the tumor cells.

Animals↗
PubMed1977

Enhancing effect of thoracotomy and/or laparotomy on the development of the lung metastases in rats after intravenous inoculation of tumor cells.

To evaluate the effect of operative stress on the tumor growth, thoracotomy and/or laparotomy were performed 48 hours after the inoculation of Sato lung cancer cells in Donryu rats. The survival time, the number of metastatic foci on the surface of the lung and the per cent-area of metastatic foci in the frontal section through the pulmonary hilus were observed. Thoracotomy and laparothoracotomy reduced significantly the survival time as compared with the control but no significant difference was found between the two test groups subjected to operative stress. The number of percent-area of metastatic foci found were inversely related to the length of the survival time.

Animals↗
PubMed1977

Early lesions and development of primary hepatocellular carcinoma in man--association with hepatitis B viral infection.

It is well known that primary hepatocellular carcinoma could be derived from chronic hepatitis and liver cirrhosis in epidemiologic studies. However, it is still not clear what kinds of hepatocyte are premalignant cells. Recently we have focused on liver cell dysplasia as a possible premalignant cell, and showed localization of alpha-fetoprotein in the cytoplasma of these cells. Although the dysplastic cells were often seen in the liver of chronic active hepatitis, hepatitis B virus associated DNA polymerase activity was also significantly high in the sera from the patients with chronic active hepatitis. In this paper, we discuss the possible role of hepatitis B virus through hepatocarcinogenesis in human.

Chronic Disease↗
PubMed1977

Antibody titer and clinical course of pemphigus.

The relationship between the titer of pemphigus antibody and the clinical course of the disease was investigated in 15 patients with various types of pemphigus. Although antibody titers generally ran parallel to fluctuations of the clinical course, the elevation of antibody titer appeared to follow the re-appearance or exacerbation of the lesions on 10 occasions in 6 patients, while it appeared to precede the latter only on 2 occasions in 2 patients. In addition, the disappearance of the antibody was considerably delayed after disappearance of skin lesions in 2 cases. These findings suggest that the pemphigus antibody is the result of skin damage, rather than the cause of pemphigus itself.

Adult↗
PubMed1977

Studies on delayed hypersensitivity in mice. I, Physicochemical and biological properties of preferential antigens for inducing delayed hypersensitivity in mice.

Variously modified protein antigens were tested by footpad assay to clarify the effect of these medications in producing delayed hypersensitivity in mice. The most potent antigen examined was carboxyl-methylated serum albumins. These antigens were highly basic proteins and hydrophobic compared with native serum proteins. They stimulate humoral antibody response in mice poorly, and remain at the subcutaneous injection site much longer than native serum albumins. In vitro tests of susceptibility of thymus and spleen cells and peritoneal macrophages to the antigens revealed that methylated serum albumins possessed the stimulatory activity to the latter and were toxic to the former. As for macrophage, fluorescein-labelled methylated serum albumin showed an affinity to their membrane and were phagocytosed, but FITC-BSA did not show any affinity to the macrophages. These biological activities to tissue or cells may be contributable to render methylated serum albumins to induce and elicit delayed hypersensitivity preferentially in mice.

Animals↗
PubMed1977

Spontaneous mutation of polysaccharide production in Alcaligenes faecalis var. myxogenes 10C3.

Alcaligenes faecalis var. myxogenes 10C3, which produces large amounts of succinoglucan and small amounts of curdlan, was genetically unstable and mutated spontaneously to a form producing more curdland than succinoglucan when stocked on nutrient agar slants. The mutation occurred in the absence of cell division when the cells were incubated in saline and was enhanced by treatment with N-methyl-N'-nitro-N-nitrosoguanidine, ethyl methane sulfonate, or ultraviolet light. Mutant strains were genetically stable and did not revert spontaneously for at least 1 year when stocked on nutrient agar slants.

Alcaligenes↗
PubMed1977

Tyramine oxidase and regulation of arylsulfatase synthesis in Klebsiella aerogenes.

The participation of tyramine oxidase in the regulation of arylsulfatase synthesis in Klebsiella aerogenes was studied. Arylsulfatase was synthesized when this organism was grown with methionine or taurine as the sulfur source (nonrepressing conditions) and was repressed by inorganic sulfate or cysteine; this repression was relieved by tyramine and related compounds (derepressing conditions). Under nonrepressing conditions, arylsulfatase synthesis was not regulated by tyramine oxidase synthesis. However, derepression of arylsulfatase and induction of tyramine oxidase synthesis by tyramine were both antagonized by glucose and other carbohydrate compounds. The derepressed synthesis of arylsulfatase, like that of tyramine oxidase, was released from catabolite repression by use of tyramine as the sole source of nitrogen. A mutant strain that exhibits constitutive synthesis of glutamine synthetase and high levels of histidase when grown in glucose-ammonium medium was subject to the catabolite repression of both tyramine oxidase and arylsulfatase syntheses. Mutants in which repression of arylsulfatase could not be relieved by tyramine could not utilize tyramine as the sole source of nitrogen and were defective in the gene for tyramine oxidase.

Amino Acid Oxidoreductases↗
PubMed1977

O-alkylhomoserine synthesis catalyzed by O-acetylhomoserine sulfhydrylase in microorganisms.

An enzyme that can synthesize O-alkylhomoserine from alcohols and O-acetylhomoserine was purified from Corynebacterium acetophilum. The enzyme was found to be identical to O-acetylhomoserine sulfhydrylase; a preparation that appeared homogeneous on polyacrylamide gel electrophoresis showed both O-alkylhomoserine-synthesizing and O-acetylhomoserine sulfhydrylase activities. Its molecular weight was determined to be about 220,000, and it consisted of two subunits. Its pH and temperature optima for the two reactions were the same. Besides catalyzing the formation of homocysteine from O-acetylhomoserine and sulfide, it also catalyzed the syntheses of O-alkylhomoserines corresponding to the alcohols added form O-acetylhomoserine and ethyl alcohol, n-propylalcohol, n-butyl alcohol, methyl alcohol, and n-pentyl alcohol, its activities with these alcohols decreasing in that order. L-Homoserine, O-succinylhomoserine, and O-acetylserine reacted with sulfide. O-ethylhomoserine, O-acetylthreonine, O-succinylhomoserine, and O-acetylserine inhibited both enzyme activities. O-acetylhomoserine sulfhydrylase purified from Saccharomyces cerevisiae also showed O-alkylhomoserine-synthesizing activity. Thus, O-acetylhomoserine sulfhydrylase seems to catalyze O-alkylhomoserine synthesis in the presence of appropriate concentrations of alcohol and O-acetylhomoserine in microorganisms.

Alcohols↗
PubMed1977

Genetic control of arylsulfatase synthesis in Klebsiella aerogenes.

It was shown that at least four genes are specifically responsible for arylsulfatase synthesis in Klebsiella aerogenes. Mutations at chromosome site atsA result in enzymatically inactive arylsulfatase. Mutants showing constitutive synthesis of arylsulfatase (atsR) were isolated by using inorganic sulfate or cysteine as the sulfur source. Another mutation in which repression of arylsulfatase by inorganic sulfate or cysteine could not be relieved by tyramine was determined by genetic analysis to be on the tyramine oxidase gene (tyn). This site was distinguished from the atsC mutation site, which is probably concerned with the action or synthesis of corepressors of arylsulfatase synthesis. Genetic analysis with transducing phage PW52 showed that the order of mutation sites was atsC-atsR-atsA-tynA-tynB. On the basis of these results and previous physiological findings, we propose a new model for regulation of arylsulfatase synthesis.

Amino Acid Oxidoreductases↗
PubMed1977

Immunological study of the regulation of cellular arylsulfatase synthesis in Klebsiella aerogenes.

Regulation of cellular arylsulfatase synthesis in Klebsiella aerogenes was analyzed by immunological techniques. Antibody directed against the purified arylsulfatase from K. aerogenes W70 was obtained from rabbits and characterized by immunoelectrophoresis, double-diffusion, quantitative precipitation, and enzyme neutralization tests. Arylsulfatase was located in the periplasmic space when the wild-type strain was cultured with methionine or with inorganic sulfate plus tyramine, but not with inorganic sulfate without tyramine, as the sole sulfur source. Tyramine oxidase was retained in the membrane fraction prepared from cells grown in the presence of tyramine. Arylsulfatase protein was not synthesized in the presence of tyramine and inorganic sulfate by mutant K611, which is deficient in tyramine oxidase (tynA). We conclude that the expression of the arylsulfatase gene (atsA) is regulated by the expression of tynA and that inorganic sulfate serves as a corepressor. In addition, strains mutated in the atsA gene were analyzed by using antibody.

Arylsulfatases↗