MANIFESTATION OF SOME ABNORMALITIES ACCORDING TO ABNORMAL INTRAUTERINE ENVIRONMENTS. STUDIES ON PHENOCOPIES IN THE MOUSE (2ND REPORT)

Abstract

Following the 1st report the author injected intravenously lithioncarmin or trypan blue solution into early pregnant mice: and there resulted many abnormal embryos which belong to phenocopies of several hereditary abnormalities. They were: pseudencephaly, distention of the central nervous system, tortuositie and malclosure of the medullary tube, flexion of the medullary tube, short-tail, taillessness, flexed tail, blebs bearing resemblance to the mylencephalic blebs, median harelip associated with pseudencephaly, ectopia cordis associated with a cranial bleb, myelocystomeningocele and severe medullary tube abnormalities associated with abnormally large heart region (pericardium) etc.These abnormalities manifested themselves regardless of the qualitative differences of the vital staining dyes used. Most of them are abnormalities of the nervous system and fissure formations. It is assumed that some excessive developmental processes may have been produced.Under the aforesaid abnormalities there are found various conditions belonging to the undermentioned ranks crossing each other: partial flexion of the medullary tube-malclosure or flexion of the medullary tube-tortuosity of the medullary tube< pseudencepaly. distention of the central nervous system.In the cases of “distention” the coverings of the brains are usually formed small and narrow. The formation of the face region is also retarded, and these embryos usually die during the 11-12th embryonic days, and in some of them the notochord seems to disappear.It has been reported by Snell et al. in pseudencephaly, and in short-tail or taillessness by Chesley, that distentions of the central nervous system are often observed. From the fact that these abnormal conditions were all obtained in the author's experiments, it may be supposed that there exist a Gloss relationship embryologically-pathologically between them.On the other hand, the fact that there were also obtained embryos with blisters, like the “myelencephalic blebs”, by the same treatment suggests the existence of some common process in the manifestation of hereditary pseudencephaly, short-tail or taillessness and myelencephalic blebs, which originate from different genes.The above-mentioned important abnormalities were most frequently observed in the group treated with intravenous injection of 0.1cc. of 1% trypan blue solution on the 8th day (24h ×8+(12+x)h) of gestation (6 of 10 pregnant mice had pseudencephalic embryos, and there were obtained in toto 11 psedencephalies, 1 median harelip and 1 ectopia cordis). In the group treated on the 7th day (about 7 1/2 day) of gestation, besides the above-mentioned abnormalities, many severe medullary tube abnormalities associated with large pericardium were especially seen.Therefore, the critical period of formation of these serious abnormalties, especially of pseudencephaly and other fissure formations, should correctly fall on the 8th day of gestation (presomite or early somite stage), while it was assumed to occur in 9-11th day in the author's previous report.