Interactions of diploid embryonal carcinoma cells and normal cell mass cells with 2.5 day mouse embryos following aggregation

Spontaneous teratocarcinomas are ovarian or testicular tumors which have their origins in germ cells. The tumors contain a disorganized array of benign differentiated cells as well as an undifferentiated population of malignant stem cells, the embryonal carcinoma or EC cells. These pluripotent stem cells in tissue culture share many properties with the transient pluripotent cells of the early embryo, and might therefore serve as models for the investigation of developmental events ill vitro. The property of EC cells of prime interest in this study is an in vivo phenomenon. Certain EC cell lines are known to be regulated ill vivo and to differentiate normally in association with normal embryonic cells, resulting in chimeric mice. These mice have two genetically distinct cell populations, one of which is derived from the originally malignant EC cells. This has usually been accomplished by injection of the EC cells into the Day 3 blastocyst. In this study, the interactions between earlier stage embryos and EC cells have been tested by aggregating clumps of EC cells with Day 2 embryos. The few previous aggregation studies produced a high degree of abnormality in chimeric embryos, but the EC cells employed had known chromosomal abnormalities. In this study, two diploid EC cell lines (P19 and Pi0) were aggregated with 2.5 day mouse embryos, and were found to behave quite differently in the embryonic environment. P19 containing aggregates generally resorbed early, and the few embryos recovered at midgestation were normal and non-chimeric. Pi0 containing aggregates survived in high numbers to midgestation, and the Pi0 cells were very successful in colonizing the embryo. All these embryos were chimeric, and the contribution by the EC cells to each chimera was very high. However, these heavily chimeric embryos were all abnormal. Blastocyst injection had previously produced some abnormal embryos with high Pl0 contributions in addition to the live born mice, which had lower EC contributions. This study now adds more support to the hypothesis that high EC contributions may be incompatible with normal development. The possibility that the abnormalities were due to the mixing of temporally asynchronous embryonic cell types in the aggregates was tested by aggregating normal pluripotent cells taken from 3.5 day embryos with 2.5 day embryos. Early embryo loss was very high, and histological studies showed that the majority of these embryos died by 6.5 days development. Some embryos escaped this early death such that some healthy chimeras were recovered, in contrast to recovery of abnormal chimeric embryos following Pl0-morula aggregations, and non-chimeric embryos following P19-morula aggregations. This somewhat surprising adverse effect on development following aggregation of normal cell types suggests that there are developmental difficulties associated with the mixing of asynchronous cell types in aggregates. However, the greater magnitude of the adverse effects when the aggregates contained tumor derived cells suggests that EC cells should not be considered the complete equivalent of the pluripotent cells of the early embryo.

Laura Dexter letter, commenting on the McLeod murder trial, October 5, 1841

Alexander McLeod was Deputy Sheriff of the Niagara District during the Rebellion of 1837-38 in Upper Canada. On December 24, 1837, he became aware of a scheme by the rebels to use the American steamboat Caroline to provide supplies to William Lyon Mackenzie and his followers on Navy Island in the Niagara River. McLeod notified the authorities in Upper Canada about the situation. A few days later, on December 29, Commodore Andrew Drew led a band of men, including McLeod, to the American side, where the Caroline was moored at Schlosser’s Wharf. A scuffle ensued, in which American Amos Durfee was killed. The Caroline was then released from its moorings, set on fire, and drifted downstream before sinking. Many Americans viewed the incident as a violation of their sovereignty. Tensions between the United States and England were already strained over a boundary dispute between Maine and New Brunswick, and the situation with the Caroline further escalated the tension. McLeod was subsequently arrested in November, 1840 in Lewiston, NY and indicted for arson and murder. The British foreign secretary, Lord Palmerston, insisted that McLeod be released and could not be held personally responsible for the incident, as he was acting on orders from authorities in Canada. Eventually, McLeod was acquitted.

Certificate that Joseph Kingsmill, sheriff, has sold 5 acres in Lot no. 22 in the 7th Concession of Crowland to Joseph A. Woodruff

Certificate that Joseph Kingsmill, sheriff, has sold 5 acres in Lot no. 22 in the 7th Concession of Crowland to Joseph A. Woodruff, May 23, 1857.