PubMed Health⌕ Search

Biomedical subjects

H Ichimura

Publications and source records attributed to H Ichimura.

At least 91 records · Page 5Linked to original sources
PubMed1978

Evaluation of succinyl neocarzinostatin in vivo.

The toxicity of the bis-succinyl derivative of the protein antibiotic, neocarzinostatin, was compared with the parent compound, neocarzinostatin (NCS), in rats. The derivative was found to be about two to five fold more active than NCS in vivo. The antitumor activity in rats bearing eleven distinct Yoshida hepatoma ascitic cell lines was tested under four possible combinations with regard to sites of drug and tumor cell administration. The results indicate that the antitumor spectrum of the derivative had changed slightly. Antitumor activity in mice was also tested with L1210 and P388 lymphatic leukemia, and with B16 melanocarcinoma. When the effect of the derivative was compared with parental NCS at the molecular level with respect to the inhibition of DNA synthesis in vitro, the specific activities of the two were found to be almost identical. These results were interpreted to indicate that the succinyl derivative of NCS was more stable to inactivation and proteolytic break-down in vivo than NCS as observed previously in in vitro studies.

Animals↗
PubMed1978

Antitumor activity of a new amino acid derivative, N6,N9-bis-(butyloxycarbonylaminomethyl)-L-citrulline.

Approximately 800 amino acid derivatives have been synthesized and screened in order to evaluate their antitumor activity against various transplantable rat ascites hepatomas. Among them, N6,N9-bis(butyloxycarbonylaminomethyl)-L-citrulline (A-924) was found to be highly effective against various rat ascites hepatomas. A-924, when given orally, exhibited prolongation of survival of rats implanted intravenously with ascites hepatoma cells such as AH-44, AH-66, AH-130, AH-66F, or AH-41C.

Administration, Oral↗
PubMed1971

Dielectric dispersion in aqueous solutions of oxyhaemoglobin and carboxyhaemoglobin.

The relative permittivity and conductivity of aqueous solutions of oxyhaemoglobin and carboxyhaemoglobin were measured over the frequency range 150kHz-100MHz. To minimize errors of measurement the investigations were carried out with three different samples of each type of haemoglobin, independent apparatus being used in two different laboratories. The dielectric increment and relaxation time were calculated at each of several temperatures from the results. These lead to a dipole moment of 400 Debyes and an activation enthalpy of 17.6+/-1.4kJ.mol(-1), both of which were found to be independent of temperature to within experimental error over the range 3-35 degrees C. The value of the dipole moment shows that the distribution of charge throughout the haemoglobin molecule is nearly symmetrical with respect to the centre of charge. The magnitude of the activation enthalpy is similar to that of the viscosity of water, in accord with the common observation that dielectric relaxation and viscosity are related phenomena. No significant differences are found between the dielectric parameters of oxyhaemoglobin and carboxyhaemoglobin. Combining the results with those obtained from X-ray diffraction of the solid a hydration value of 0.45g of water/g of protein is suggested, subject to the limitations of the model used. Finally, the results indicate the presence of a subsidiary dispersion, which could be attributed to the above quantity of bound water having a static permittivity of about 100 and a relaxation frequency in the region 100-200MHz.

Carbon Monoxide↗