IONIZING RADIATIONS AND CONGENITAL ANOMALIES IN VERTEBRATE EMBRYOS
Similar anomalies of the central nervous system may be produced in fish or mouse embryos as a result of x irradiation at certain stages of development. These stages include any time prior to the completion of neurogenesis, even so far back as the zygote. The anterior end of the fish or mouse embryo appears to be adversely affected by x irradiation, whether the exposure occurs during neurogenesis or even during the first cleavage prior to any neural differentiation. Thus, there appears to be a cephalic gradient of radiosensitivity, especially evident since the more posterior structures such as heart, lungs, and gastro-intestinal tract appear largely to be unaffected, no matter when irradiation occurs. X irradiation of the fish or mouse embryo does not produce uniform effects in all exposed individuals. Even within a single clutch of fish embryos or a litter of mice, there may be a wide variation in the effects of similar exposure to ionizing radiations. Nevertheless, the major effect is on the central nervous system and, whether or not a gross anomaly is produced, it is believed that every mouse embryo exposed to 50 r or more or every fish embryo exposed to 300 r or more will have neural deficiencies. These may be reflected in general stunting, microcephaly, or possibly even in functional reduction in behavior efficiency. There is evidence that the embryo attempts to maintain its topographical relations, even with the deficiencies due to irradiation during development, so that stunted animals result which appear to be rather normal in organ proportions. The lowest exposure to x rays which may cause permanent deficiencies has not yet been determined. Such data from fish and mouse embryos, even though they agree, cannot be safely extrapolated to the human. Nevertheless, they are suggestive that embryonic and fetal exposure of the human embryo should be avoided at all stages of development since neurological deficiencies may result. Human data of this sort are not available and until they are, caution is recommended in the use of ionizing radiations on human gonads and embryos, at least until direct data are contra-indicative. (auth)
- Research Organization:
- Columbia Univ., New York; Marine Biological Lab., Woods Hole, Mass.
- NSA Number:
- NSA-14-023941
- OSTI ID:
- 4158473
- Journal Information:
- Acta Embryol. Morphol. Exptl., Journal Name: Acta Embryol. Morphol. Exptl. Vol. Vol: 2
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ANIMALS
BEHAVIOR
BIOLOGY AND MEDICINE
BRAIN
EFFICIENCY
EMBRYOS
ERRORS
FETUSES
FISH
GENETICS
GONADS
HEART
INTESTINE
LUNGS
MALFORMATIONS
MICE
MITOSIS
NERVOUS SYSTEM
PREGNANCY
RADIATION DOSES
RADIATION EFFECTS
RADIATION INJURIES
RADIATION PROTECTION
RADIOSENSITIVITY
SAFETY
STOMACH
TISSUES
VARIATIONS
X RADIATION