Detection of micronuclei in peripheral blood of mitomycin C-treated mice using supravital staining with acridine orange.

The induction of micronuclei in peripheral blood from mitomycin C (MMC)-treated mice was examined using a supravital acridine orange staining method. Male ICR mice were intraperitoneally given MMC at a single dose of 0.25, 0.5, 1, or 2 mg/kg. Blood was sampled from the tail 24, 48, 72, and 96 h after treatment, and the frequency of micronucleated reticulocytes (MNRETs) was examined. The induction of MNRETs peaked at 48 h after treatment with MMC; there was a clear, dose-related increase in MNRETs. In a multiple-treatment study, mice were treated with 4 consecutive daily injections of MMC at a dose of 0.13, 0.25, 0.5, or 1 mg/kg. The frequency of MNRETs increased markedly 24 h after the second treatment as compared with the first treatment, and did not change significantly until 24 h after the fourth treatment. The frequency of MNRETs decreased to approximately control values 96 h after the last treatment. In addition, a slight but statistically significant increase in the number of micronucleated normochromatic erythrocytes in peripheral blood was detected by means of Giemsa staining 7 days after the last treatment. These results confirm the usefulness of the supravital acridine orange staining method to evaluate micronucleus induction in mouse peripheral blood.

Cervical esophageal motility: evaluation with US in progressive systemic sclerosis.

High-resolution ultrasound (US) showed that initial peristalsis propelled ingested soda smoothly and rapidly in 20 volunteers without symptoms who met both manometric and radionuclide esophageal scintigraphic (RES) criteria for normal motility. Twenty-eight patients with progressive systemic sclerosis were classified according to results of RES as follows: group 1, normal esophageal motility (three patients [11%]); group 2, hypomotility of the esophagus, excluding the cervical esophagus (18 patients [64%]); and group 3, hypomotility of the cervical esophagus (seven patients [25%]). In the seven patients of group 3, US demonstrated that an incomplete peristalsis sequence or a feeble peristalsis propelled the soda in a slow and/or to-and-fro motion with low velocities. In the other 21 patients (75%), the soda passed through the esophagus smoothly and rapidly. Retention of soda in the cervical esophagus was not limited to patients with hypomotility of the cervical esophagus. It is concluded that US is useful in evaluation of cervical esophageal motility.