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Mechanism and risk factors for the development of monozygotic twins in mammals
Žabková, Světlana ; Krylov, Vladimír (advisor) ; Petr, Jaroslav (referee)
Monozygotic twins result from the splitting of one embryo in early embryonic development. The developmental stage, in which the splitting occurs, is the main factor determining the degree of sharing fetal sacs. The etiology and mechanism of monozygotic twinning are still unknown. The human and two species of armadillo, Dasypus novemcinctus and Dasypus hybridus are the only mammals that regularly produce monozygotic multiple pregnancies. The spontaneous occurrence of monozygotic twinning is 0,45 % of all births. The monozygotic twin pregnancies have been reported to occur at a higher rate following the increasing interest of assisted reproduction technologies. In certain consideration, we understand them as a side effect of infertility treatment because monozygotic twins result in a higher rate of prenatal mortality, premature birth and congenital anomalies than singleton pregnancies. This bachelor thesis aims to summarize knowledge about the formation of monozygotic twins in mammals. Also, it tries to discuss potential mechanisms and risk factors which could influence their formation. Monozygotic twins are an important model for explaining the genetic predisposition of some diseases. The thesis also introduces the ways of experimental production of monozygotic twins. Keywords: monozygotic twins,...
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Ethical aspects of assisted reproduction
STAŇKOVÁ, Eliška
The dissertation follows up metods of assisted reproduction and its ethical aspects that are described with their particular metods of assisted reproduction. It summarizes opinions of supporters, such as doctors, but also opinions of respondents such as ethicists or theologian. Dissertation is mostly focused on moral status of embryo and their superfluous creations. It warns us to be aware that assisted reproduction can leads to violation of human dignity but also let us learn ways of assisted reproduction which are considerate to embryos and which do not jeopardize human dignity. It describes problems of legislation in Czech Republic but also in Germany and Great Britain. One part is also dedicated to opinions of catholic Church. Last chapter describes involuntary childlessness.
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Infertility and ethical aspects of assisted reproduction.
VALEČKOVÁ, Lucie
This work deals with infertility and the ethical aspects of assisted reproduction. Theoretic part is devoted to male and female infertility, its causes, the methods and issues of assisted reproduction, which are ethically unacceptable as shledávány, where some are tolerated under certain conditions. The practical part of this thesis are examined attitudes of infertile couples and the public on the ethical aspects of assisted reproduction.
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