[Short-term assay of colon carcinogen--induction of micronuclei and apoptosis by dimethylhydrazine in the mouse colon crypt cells]

The frequencies of micronuclei and apoptosis in the colon crypt cells of mice treated with colon carcinogen were studied. Two strains of mice, inbred C57BL and close colony Kun-ming mice were used in this experiment. The mice were killed at 24 hr after intraperitoneal injection of dimethylhydrazine (DMH) at doses of 10, 20 and 40 mg/kg body weight. The results indicated that the frequencies of micronuclei and apoptosis in the colon crypt cells of both C57BL and Kun-ming mice were positively correlated quantitatively with the doses of DMH. Our results are similar to that of Heddle obtained in C57BL mice. We propose that the assay of micronuclei and apoptosis in mouse colon crypt cells might be a rapid and sensitive test and useful as a screening method for potential colon carcinogens. Kun-ming mice may be used as the test animal for detecting nuclear anomalies in this assay in lieu of C57BL mice.

[Gastric cancer treated by hematoporphyrin derivative(HPD)-laser--histopathological study of 10 gastrectomy specimens]

10 patients with gastric carcinoma treated by HPD-laser preoperatively are reported. The gastric lesions were irradiated with laser beam delivered by a quartz fibre through the fiberoptic gastroscope 48-72 hours after intravenous injection of HPD (5.0 mg/kg) about 2 weeks before operation. In the resected specimens, the histological changes following HPD-laser therapy were studied. The cancer cells in the irradiated areas showed degeneration and necrosis in varying degrees. Because of the fact that the light spots were small and the penetration not deep enough, the cancer cells beyond the irradiated area and those infiltrating more deeply or beyond the gastric wall did not show any evident changes while metastatic cancers in the lymph nodes showed no changes at all. These facts may suggest that the HPD-laser therapy should not be used as the main therapeutic method to replace operation, radiotherapy or chemotherapy for gastric cancers in either advanced or early stage.