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The oncogenic effect of ethylnitrosourea (ENU) on rabbits during the organogenesis was studied. ENU, dissolved in sodium phosphate (pH 6.0), was injected in a 50 mg/kg dosis intravenously in pregnant dams between the 8th and 10th day of gestation. From 12 offspring 8 grew up normally and appeared unremarkably until 30--36 months of age when neurologic signs first developed. Six rabbits showed one or more tumors along the peripheral nerves. Two rabbits were bearing brain gliomas in the vicinity of the 3rd ventricle. The tumors of the peripheral nervous system (PNS) were of variable size and soft consistency; they had a cut surface of spongy and even cystic appearance. Histologically, the PNS tumors resemble Schwannomas of the Antoni B type. An ultrastructural study of these neoplasms disclosed cells featuring a basal lamina type of lining characteristics of Schwann cells. These findings demonstrate that the exposure of rabbits to ENU during organogenesis results in the induction of neurogenic tumors which become clinically manifest late in life. It seems, therefore, that the selective oncogenic effect of ENU on the nervous tissues of the exposed animals depends exclusively on the stage of organogenesis at which the drug is brought to bear upon the target organ anlage.  相似文献   

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Application of methyl- and/or ethylnitrosourea during intrauterine or postnatal life did not induce tumours in Macaca mulatta. Most of the animals survived 5 to 10 years after the beginning of the experiments and are in good health at present. Complete postmortem examinations were performed in all monkeys who died.  相似文献   

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Based on our first 200 investigations computed tomography of the heart is demonstrated as a new non-invasive roentgenography on typical examples and compared with the findings of the conventional roentgenogram. With the present technology the following indications for computed tomography of the heart seem to be reasonable: Calculation of size and volume of the cavities of the heart; intracavitary space occupying lesions (tumor, thrombus): demonstration of the thickness of the ventricular wall and ventricular septum and their changes caused by hypertrophy, myocardial infarction or septal defect; demonstration of aortic and ventricular aneurysm; demonstration of pericardial effusion, pericardial tumor, pericardial cyst of lipoma.  相似文献   

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After remarks about the history of pediatric electroencephalography some particularly important neurophysiological and especially electroencephalographical studies out-of the last ten years are reviewed: polygraphic studies in healthy and sick newborns, spectralanalytical investigations of the EEG in twins, infants and older children. The review is closed by some critical considerations about possibilities and limitations of the automatic analysis of the childhood EEG.  相似文献   

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