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Biomedical subjects

N Otsuka

Publications and source records attributed to N Otsuka.

At least 181 records · Page 10Linked to original sources
PubMed1981

A scanning electron microscopic study of the two-step effect of cytochalasin B on Ehrlich ascites tumor cells.

The effect of cytochalasin B (CB) on the surface structure of Ehrlich ascites tumor cells was investigated using the scanning electron microscope. The effect occurs in two steps: formation of zeiotic knobs on the cell surface and subsequent grouping of the knobs at one pole of the cell. The early step of zeiotic knob formation occurs at low concentrations of CB (0.5-1 microgram/ml) at 37 degrees C and at high concentrations of the drug (5-10 microgram/ml) at low temperature but within 1 min at 37 degrees C. This step is only partially inhibited by 5 x 10(-3) M sodium azide. The subsequent grouping of zeiotic knobs lasts for more than 2 min at 37 degrees C and occurs only in the case of high concentrations of CB. It is inhibited by sodium azide and is often associated with grouping of the microvilli, which are then lost from all of the cell surface except the area of knob-grouping.

Animals↗
PubMed1981

Effects of prostaglandin on experimental bone malignancy and on scintigrams of bone and marrow.

The correlation between prostaglandin E (PgE) and scintigrams of bone (Tc-99m MDP) and bone marrow (Tc-99m SC) was investigated in normal and VX-2-bearing rabbits. PgE in plasma of normal rabbits was 486.2 +/- 185.7 pg/ml (n = 86) and the maximum-to-minimum (max/min) ratio was 1.85 +/- 0.26 at 4 wk after tumor implantation. In rabbits with VX-2 transplanted into femoral muscles, PgE was in the normal range unless the tumor invaded bone. PgE did not increase significantly in rabbits when the tumor was transplanted into the marrow cavity. When tumor invaded bone, PgE increased markedly (to 1335 +/- 584 pg/ml). Elevation of PgE did not necessarily coincide with the appearance of positive bone scans. PgE in an indomethacin-treated group was not higher than in the untreated group. There was no significant difference between the two groups regarding the time of appearance of abnormal bone scans. However, when the number of transplanted cells in the bone marrow was reduced, the treatment with indomethacin delayed the increase in tracer uptake in the affected bone and resulted in a photon-deficient area. Indomethacin may suppress the local acceleration of calcium metabolism.

Animals↗
PubMed1980

Uptake and excretion of 67Ga-citrate in malignant tumors and normal cells.

Using in vivo and in vitro experimental models, the uptake and excretion of 67Ga-citrate in tumor cells and normal cells were studied. The time-lapse accumulation of 67Ga in the tumor of rats bearing Yoshida sarcoma reached its peak 24 h after the administration of 67Ga and gradually decreased thereafter. However, the excretion of 67Ga from the tumor was less than that from normal lung. For culture cells in vitro, the uptake of 67Ga increased with lapse of contact time between 67Ga and the cells, but there was no distinct difference between the results for tumor cells and normal skin fibroblasts. The excretion of 67Ga from the cells tended to decrease with prolongation of the contact time, the excretion from tumor cells being only about 10% after a contact time of 24 h. This indicated a significant delay in excretion in comparison with that of normal skin fibroblasts. This delay in the excretion of 67Ga may be an important factor in the tumor accumulation of 67Ga.

Animals↗
PubMed1980

99mTc-colloid kits from the view point of the accretion in the bone marrow--with special reference to comparison with 198Au-colloid.

With 9 kinds of available 99mTc-colloid kits for RES imaging, especially from the aspect of RES imaging of the bone marrow, observations were conducted on pH, the presence of free 99mTcO4(-), labelling efficiency, rabbit blood clearance, the uptake in RES, urinary excretion, as well as the scintigraphy with rabbits and clinical cases. Compared to 198Au-colloid, marrow to liver ratio was found to be about the same, but its uptake to the spleen and liver was greater. In particular its urinary excretion was much more marked than 198Au-colloid, and in clinical use the bladder was more often delineated. This fact seems to suggest that it is desirable to develope a 99mTc-colloid more suitabale for the bone marrow scintigraphy.

Anemia, Aplastic↗
PubMed1980

Experimental and clinical studies on differential diagnosis of bone diseases with nucleomedical procedures.

This report is a study of the differential diagnosis of bone diseases using nucleomedical procedures. Experimental and clinical studies on the accumulation of 201Tl and 67Ga in bone inflammation and bone tumors were performed. Also, the degree of deposition of 99mTc-phosphorous compounds represented as a color difference was evaluated for a differentiation between malignant and benign diseases of the spine and shoulder. Uptake of 201Tl in inflammation of the spine and in tumor of the pelvis of rabbits was very low, while that of 67Ga was high. Uptake of 67Ga decreased gradually with lapse of time after the onset of inflammation. These experimental results agreed with clinical studies. The detectability of malignant tumors with 201Tl was inferior to that with 99mTc-label and 67Ga, although osteolytic lesions were occasionally 201Tl-positive. In terms of color range, the difference was 2 or less in spines of normal subjects and 3 or more in the metastatic bone disease and compression fracture. This difference was not statistically significant. Since 67Ga scan was occasionally negative in compression fracture, a differentiation was considered to be possible in such a case. A combined study of bone imaging with 99mTc-phosphorous compound including color difference, 67Ga imaging, bone-marrow imaging and radiography are considered to be helpful for the differentiation.

Animals↗