12 resultados para embryonic death

em Brock University, Canada


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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.

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Genetic chimeras made by aggregating early mouse embryos have many uses in developmental biology and have also provided insights into embryonic growth regulation. There is an indication that the embryo can regulate for an increase in size because although aggregation chimeras are twice as big as normal embryos when made, they are born of normal size. Upward regula..... tion of size reduced embryos is also possible. Half embryos made by the isolation or destruction of one of the blastomeres of a 2-cell embryo are also born of normal size. Little is known about the timing or the mechanism of this size regulation. In this study, the timing of size regulation in double and half embryos was clearly established by comparison of cell numbers derived from serial reconstruction of light microscope sections of control and experimental embryos. It was shown that size regulation in double embryos occurred around 6dl6h and in half embryos by 7dOh. Size regulation occurred in all tissues at the same time indicating a single control mechanism for the entire embryo. More detailed examination of the growth of double embryos revealed that size regulation occurred by alteration in cell cycle length~ No excessive cell death was found in double embryos compared to the controls and continuous labelling with [3H] thymidine showed no large non-dividing cell population in double embryos. However, a comparison of the mitotic index of double and control embryos after colcemid treatment, revealed a large difference between the two around 5dl6h to 6d16h. During this period, control embryos underwent a proliferative burst not shown by the double embryos. The mechanism for cell cycle control is not clear; it may be intrinsic to the embryo or determined by the uterine environment. Evidence was found suggesting that differentiation in the postimplantation embryo was cell number dependent. The timing of differentiative events was examined in half, double and control embryos. Proamnion formation, which occurs prior to size regulation, occurs at the same cell number but at different times in the three groups of embryos. However mesoderm which appears after size regulation was seen at the same time in all grollps of embryos.

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This study investigated loss, death and dying, reminiscing, coping and the process of adaptation from the sUbjective perspective. A number of theories and models of death and dying were reviewed in the background literature search with the focus on reminiscing as a coping phenomenon. The format of the study was audio-taped interviews with ten sUbjects and the recording of their memories and reminiscing of life stories. The sUbjects were required to complete an initial questionnaire in a demographic data collection process. Two separate interviews consisted of a primary data collecting interview and a verification interview four to eight weeks later. An independent chart review completed the data collecting process. Data analysis was by the examination of the emerging themes in the subjects' personal narratives which revealed the sUb-categories of reminiscing, loss (including death and dying), acceptance, hope, love, despair and belief. Belief was shown to be the foundation and the base for living and reminiscing. Reminiscing was found to be a coping phenomenon, within the foundation of a belief system. Both living and reminiscing revealed the existence of a central belief or value with a great deal of importance attached to it. Whether the belief was of a spiritual nature, a value of marriage, tradition, a work ethic or belief in an abstract value such as fate,it gave support and control to the individuals' living and reminiscing process. That which caused despair or allowed acceptance indicated the sUbjects' basic belief and was identified in the story narrations. The findings were significant to health care in terms of education, increased dignity for the elderly and better understanding by society. The profiles represented an average age of 86.3 years with age showing no bearing on the life experiences associated with the emerging themes. Overwhelmingly, belief was shown to be the foundation in reminiscing. A Judeo-Christian cultural value base supported the belief in 90% of the sUbjects; however, different beliefs were clearly shown indicating that belief is central to all thinking beings, in everyday life and in reminiscing. Belief was not necessarily spiritual or a practised or verbalized religion. It was shown to be a way of understanding, a fundamental and single thread tying the individual's life and stories together. The benefits were the outcomes, in that knowledge of an individual's belief can optimize care planning for any age group, and/or setting. The strength of the study was the open question format and the feedback process of data verification. The unrestricted outcomes and non-specificity were significant in a world where dying is everybody's business.

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Terror Management Theory (TMT) suggests that human beings battle to protect ourselves from the potential terror resulting from the juxtaposition of our need for selfpreservation and our unique human ability to realize that we cannot avoid death. Over 150 studies have shown that when people are primed with the awareness of mortality they grasp onto their cultural world view more tenaciously than when they are primed with another unpleasant stimulus (i.e., show "cultural world view defense"). Applying the principles ofTMT, the first purpose of the present research was to examine whether the amount of peak experiences reduce the tendency to show cultural world view defense (an indicator of unconscious death fear) after a death prime. The second purpose was to examine a new model of implicit spirituality, by testing proposed relationships between implicit spirituality, peak experiences and intrinsic religiosity, and by testing whether peak experiences and/or intrinsic religiosity mediate the relationship between implicit spirituality and conscious and/or unconscious death fears. Skydivers were chosen as the primary participants for this research because of their unique characteristics in the context of TMT research. Previous research suggests that veteran skydivers have peak experiences as they skydive, and I assumed that their peak experiences would not be influenced by intrinsic religious beliefs. Novice skydivers may have their implicit spirituality brought forth because of their proximity to possible death. The willingness of both groups to place themselves close to death allowed their reactions to unconscious and conscious death fears to be assessed in a real setting. Novice skydivers' proximity to death made them an ideal group to study to see whether intrinsic religiosity mediated the relationship between their implicit spirituality and conscious and/or unconscious death fears. One hundred and twenty-five people participated in this research: 38 veteran and 46 novice skydivers, as well as 41 people who accompanied them to the drop zone. Of these, 23 veterans, 19 novices, and 22 friends returned a follow-up packet of questionnaires three weeks later. As expected, the veterans' unconscious death fear scores remained stable from pre-jump to post-jump (after the death prime), and three weeks later, whereas the novices' scores increased, but only marginally. As predicted, the novice skydivers' implicit spirituality was significantly higher than the veterans' and was negatively correlated with their conscious death fear, which was not mediated by their intrinsic religiosity. Only the novices' follow-up (trait) implicit spirituality correlated negatively with their pre-jump unconscious death fear. Among both groups of skydivers, there were significant relationships between implicit spirituality and peak experiences, and although the novices were significantly higher on peak experiences after the jump, peak experiences did not mediate the relationship between implicit spirituality and unconscious death fear for either group. In both groups follow-up intrinsic religiosity correlated with implicit spirituality. Peak experiences and intrinsic religiosity were not related with one another, suggesting that these are different ways of accessing an implicit spirituality. Results imply that implicit spirituality was brought forth (in the case of novice skydivers who were consciously close to death) and can be accessed through both peak experiences and intrinsic religiosity.

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This study explores the mortuary remains of children from the MH-LH I periods of the Argolid, Greece. This examination concentrates on how the child in death acted as a tool for wealth and status display. Here, children are understood to have perpetuated, maintained, and reinforced status distinctions between families in their community. The analysis of one hundred child burials that date to these periods illustrates how the burials of children were important opportunities used by the families of children to display wealth and status. Thus, children can be viewed as important factors in the reorganization of social structure in the transition from the Middle to Late Helladic.

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The aim of this study was to describe the nonlinear association between body mass index (BMI) and breast cancer outcomes and to determine whether BMI improves prediction of outcomes. A cohort of906 breast cancer patients diagnosed at Henry Ford Health System, Detroit (1985-1990) were studied. The median follow-up was 10 years. Multivariate logistic regression was used to model breast cancer recurrence/progression and breast cancer-specific death. Restricted cubic splines were used to model nonlinear effects. Receiver operator characteristic areas under the curves (ROC AUC) were used to evaluate prediction. BMI was nonlinearly associated with recurrence/progression and death (p= 0.0230 and 0.0101). Probability of outcomes increased with increase or decrease ofBMI away from 25. BMI splines were suggestive of improved prediction of death. The ROC AUCs for nested models with and without BMI were 0.8424 and 0.8331 (p= 0.08). I f causally associated, modifying patients BMI towards 25 may improve outcomes.

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Sir George Yonge (1732-1812) was a baronet, politician and colonial governor. He was a Member of Parliament for Honiton from 1754-1761 and 1763-1796, British Secretary at War from 1782-1783 and 1783-1794, and Governor of the Cape colony from 1799-1801.

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General Isaac Brock was a British Army officer and administrator who was promoted to Major General. He was responsible for defending Upper Canada against the United States. He died at the Battle of Queenston Heights during the War of 1812. Bartholome Houde and George E. Tuckett (Tuckett was mayor of Hamilton Ontario in 1896) manufactured and sold tobacco before Confederation. In 1841, the company was called B. Houde and Grothe. When Houde retired in 1822 his son in law, Francis Xavier Dussault took over the company. In 1903, the company was called B. Houde and Company Ltee. and it was run by Dussault’s two sons J.A. Dussault and J.E. Dussault. The B. Houde Company had become part of American Tobacco Ltd. which merged with Empire Tobacco Co. Ltd. to form the Imperial Tobacco Company in 1908 in the St. Henri district of Montreal. In 2008, the company celebrated their centennial. Cigarette silks were either enclosed in packets of cigarettes or were redeemable by mail. People would sew these silks together to create quilts or table covers. Some cigarette packages even included instructions for making these items.

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Canadian Expeditionary Force Death Certificate stating that Samuel DeVeaux Woodruff was killed in action on the 13th of July, 1918, dated Sept. 20, 1919.

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Clipping of the obituary for Amy Constance Woodruff Miller, daughter of the late W. Henry Miller and Amy Woodruff Miller. The funeral was at St. George’s Church and Interment at Victoria Lawn Cemetery on Feb. 8, 1949.

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Clipping of the obituary of Francis Woodruff, n.d. Clipping of the announcement of the engagement of Gladyse Wanita Palling to Lieut. Samuel DeVeaux Woodruff of the 176th Overseas Battalion, n.d.