Pregnant ICR mice were treated with single whole-body X-radiation at a dose of 0.24 Gy on day 10, 13, or 15 of gestation. Fetuses were obtained from mothers during 1 and 24 hours after irradiation. Pyknotic cells in the ventricular zone of telencephalon were counted in serial histological sections. Incidence of pyknotic cells peaked during 6 and 9 hours after irradiation in each gestation day group. Then, dose-response curves were obtained 6 hours after 0-0.48 Gy of irradiation. All three dose-response curves showed clear linearity in the dose range lower than 0.24 Gy. Ratios of radiosensitivity estimated from the slopes of dose-response curves in day 10, 13, and 15 groups were 1, 1.4, and 0.4, respectively. These demonstrated that ventricular cells in the day 13 fetal telencephalon were the most radiosensitive among the three different age groups. In order to confirm the presence of the highly radiosensitive stage common to mammalian cerebral cortical histogenesis, pregnant F344 rats were treated with single whole-body gamma-irradiation at a dose of 0.48 Gy on day 13, 14, 15, 17, or 19 of gestation. The incidence of pyknotic cells in the ventricular zone of telencephalon was examined microscopically during 1 and 24 hours after irradiation. The peak incidence was shown 6 hours after irradiation in all the treated groups, and the highest peak incidence was shown in day-15-treated group. The developmental stage of telencephalon of day 15 rat fetuses was comparable to that of day 13 mouse fetuses. Thus, the highest radiosensitivity in terms of acute cell death was shown in the same developmental stage of brain development, i.e., the beginning phase of cerebral cortical histogenesis, in both mice and rats.

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A delayed matching-to-sample paradigm (DMTS), employing a visual task in which Ss (capuchin, monkeys) could not fall back on mediating behaviors of a positional or orientational nature, was used to investigate interference phenomena in short-term memory (STM). Sample-set size, i.e., the number of stimuli used (two, three, or four), was varied orthogonally with delay interval (1, 3, 9, or 18 sec.). Within the parametric limitations of the experiment no evidence for STM interference effects was found. Based on a longterm increase in base-line behavior and an apparent discriminability effect upon DMTS performance, a modified decay interpretation of the data was suggested.

A 57-year-old woman was admitted to our hospital for lumbago, weight loss and weakness of her right lower extremity. Leukocytosis was evident with marked eosinophilia (65.5% = 46,000/mm3), and the chest roentgenogram showed diffuse reticular shadows throughout both lung fields and a left pleural effusion. The pleural effusion contained 22.4% eosinophils with no immature cells. Biopsy of a thumb-sized mass on the chest wall revealed a T-cell lymphoma of pleomorphic type. The diffuse pulmonary shadow was diagnosed as chronic eosinophilic pneumonia by autopsy. This was a relatively rare case of T-cell lymphoma, in which an eosinophilic pneumonia and eosinophilic pleural effusion were observed.