Nagaoka ferromagnetism in large-spin systems -Fermion and Boson systems--

We study magnetic properties of itinerant quantum magnetic particles described by a generalized Hubbard model with large spin ($S>1/2$) which may be realized in optical lattices of laser-cooled atom systems. In fermion systems (half-integer spins), an extended form of Nagaoka ferromagnetism may be realized. However, as novel aspects of the large spin cases, we found that the condition on the lattice connectivity is more stringent than in the case of $S=1/2$ particles, and that the system shows a peculiar degenerate structure of the ground statein which the ferromagnetic state is included. In contrast, it turns out that the ground state of itinerant bosonic systems (integer spins) has a degenerate structure similar to that of fermion system with $S>1/2$ regardless of the shape, connectivity or filling of the lattice, and that the state with the maximum total spin is always one of the ground states

A Study of Long-Term Metabolism of Nucleic Acid in the Repair Process of Cancer Cells with Cis-diamminedichloroplatinum (II)

CDDP is one of the anticancer drugs in which the presence of the repair mechanism has been pointed out. Thus, using established pulmonary cancer cells, we evaluated the metabolism of DNA and RNA in damaged cells treated with CDDP (0.1, 1.0, 10μg/ml) by means of 3 H-TdR . 3 H-UR incorporation assay for 15 days referring to the growth curve and colony forming assay. 3H-TdR uptake inhibition rate in CDDP treatment was higher than 3H-UR uptake inhibition rate and showed good correlation with the inhibition rate of colony formation. In order to evaluate the activity of metabolism of DNA and RNA, the experimental period was divided into two parts : an early stage (2-10 days) and a later stage (7-15 days), and changing phases of uptake of 3H-TdR and 3H-UR was estimated as an increased rate. In the early stage, cells treated CDDP at lower concentrations tended to show more active DNA and RNA metabolism, especially RNA. In the later stage, cells with 0.1μg/ml CDDP which had shown only slight growth inhibition in the early stage revealed lower activity than that in the early stage. Cells with 1.0vg/ml CDDP which showed regrowth after 7 days, and cells with 10μg/ml CDDP which were not recognized with proliferation were observed with more active metabolism of RNA than that in the early stage. Those results indicated that metabolism of RNA is closely associated with the cellular repair process by CDDP

A Trial in Estimating Chemosensitivity from Biopsy Specimen by Flow Cytometry

To select the sensitive anticancer agents for the treatment of patients with carcinoma, chemosensitivity should be timely assessed from biopsy specimen for patients with gastric carcinoma. Histogram of DNA analysis from biopsy specimens revealed the disappearance of GZM accumulation in reflection of effects of anticancer drugs prior to the appearance of clinical signs. In conclusion, DNA analysis from biopsy specimens is of great value in assessing the efficacy of anticancer drugs in the course of drug treatment and also in knowing the drug sensitivity to the tumor timely

Radiation-induced carcinoma of the rectum

Two patients with rectal cancer induced by irradiation for the treatment of uterine cancer were reported. Surgical outcome for radiation-induced cancer was satisfactory as far as the primary focus was well controlled. Definition of radiation-induced cancer also was discussed. It is the most important factor to be a long time interval of more than 10 years by detection of rectal cancer after irradiation and to reveal a histologic pattern concerning irradiation tissue damage