Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 7 uppsatser.

Within the context of medical ethics the term 'instrumentalism' is broadly understood as the practice of 'using people' to achieve some end, where the end is considered to be of some good. It is a practice that has recently come under fire in light of developments in medical research that propose to use fetal tissue obtained from elective abortions. Ethicists opposed to this kind of instrumentalism usually invoke Kant's dictum that one should never treat humanity only as a means but always as an end in itself, and allege that the instrumental use of others is 'dehumanizing' and immoral. Moreover, opponents of fetal instrumentalism claim that using fetal tissue in research is a morally tainted, 'doubly' offensive practice since it depends on tissue obtained from voluntary abortions. In this thesis, I challenge both of these claims and argue that using fetal tissue in medical research constitutes an acceptable kind of instrumentalism. Furthermore, I argue that the issue of abortion and the use of fetal tissue in research are two ethically separable issues that warrant distinct ethical judgments. My project begins with an analysis of instrumentalism, which is then applied to show how using the aborted fetus to attain valuable therapeutic goals is a morally justified instrumentalism. I then proceed with an evaluation of the arguments central to the instrumentalist debate, and show how the normative separation between abortion and fetal tissue use is possible. / Thesis / Master of Arts (MA)

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [90]-110).

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

The aim of this dissertation is to examine and analyse the judicial framework with regard to embryonic stem cell research and cloning in South Africa. The examination is conducted within the framework of the South African and United Kingdom's legal systems. Focus is placed on aspects of medical law, human rights law as envisaged in the Constitution of the Republic of South Africa, and the law of persons. The specific focus of this dissertation is to examine the intense debate on the moral and legal status of the embryo and fetus in South Africa. A comparative study is undertaken, with the United Kingdom as a background against which recommendations for the South African framework are made. The study firstly provides a clinical overview of stem cell research and cloning. Secondly, the concept of life, in particular human life; the protection of the embryo and fetus under the constitutional guarantee of the right to life, among other constitutionally protected rights, are examined. In this context, the most important finding is that although the fetus is not a bearer of constitutional rights the state has a constitutional duty to protect fetal life in terms of an objective value system. Thereby, the state is permitted to regulate abortion, fetal tissue research, and embryo research to protect fetal life. In particular, the aim of this dissertation is to present a critical summary of the major debates and policy responses relating to embryonic stem cell research and cloning techniques, drawing attention to some of the challenges posed by conflicting moral values in an era of global scientific endeavour, and to provide an analysis of the key ethical and regulatory implications for stem cell therapy. The most important findings are that current South African legislation remains fragmented and ineffective in the manner in which embryonic stem cell research and cloning are regulated. This finding leads to a summary of recommendations, which attempts to provide specific remedies in order to adapt the current regulatory framework in South Africa. / Dissertation (LLM (Public Law))--University of Pretoria, 2007. / Public Law / LLM / unrestricted

Aujourd'hui, l'un des modèles de souris humanisées le plus robuste est obtenu en injectant des cellules souches hématopoïétiques humaines (HSC) issues de foie fœtal humain et en implantant du thymus fœtal autologue. Ce modèle, appelé BLT (Bone marrow/Liver/Thymus), s'est révélé capable de supporter une reconstitution, une maturation et une sélection optimales des cellules T. Les souris BLT sont utilisées pour de nombreuses études telles que la compréhension de la biologie du VIH ou plus récemment en médecine régénérative. Grâce à ce modèle, nous avons pu d’une part étudier le rôle des cellules dendritiques plasmacytoïdes (pDC) lors de l’infection par le VIH mais aussi mieux comprendre la formation in vivo de tératomes lors de l’utilisation d’iPSC. Cependant, l'une des principales limites de cette technique réside dans l'obtention du tissu fœtal. Ici, nous avons décrit un nouveau protocole de souris humanisées greffées avec du thymus humain en utilisant des matériaux plus accessibles: du thymus humain retiré lors d’une chirurgie cardiaque chez des nouveaux-nés ou des enfants, et des HSC de sang de cordon. Des morceaux de ces thymus ont été implantés dans les quadriceps de souris immunodéficientes, après avoir été mis en culture. Ces souris CCST (Cord blood and Cardiac Surgery Thymus) ont permis une prise de greffe importante et un meilleur développement des lymphocytes T humains que les souris humanisées sans thymus. Les lymphocytes T des souris CCST et BLT ont montré une fonction similaire, évaluée par des tests de prolifération ex vivo et par rejet de lignées de cellules leucémiques allogéniques in vivo. Nous avons testé l’intérêt de cette nouvelle stratégie dans le modèle de l’infection au VIH-1, qui représente le modèle type de l’utilité des BLT. Nous avons montré que les souris CCST sont sensibles à l'infection par le VIH-1 par voie muqueuse ou intrapéritonéale, comme l'indique la détection de l'ADN du VIH et des cellules p24 +, similairement aux souris BLT. Les souris CCST ont présenté des réponses de lymphocytes T spécifiques du VIH-1 ex vivo plus efficaces que les BLT. Lors du traitement antirétroviral, les souris CCST, comme les BLT, ont vu leur charge virale diminuer. Ces résultats démontrent que les souris CCST représentent une alternative au modèle de souris BLT classique. Ces thymus, éthiquement plus facile à obtenir, peuvent être utilisés pour générer un grand nombre de souris par rapport aux thymus fœtaux. / Immunodeficient mice engrafted with human immune system provide an exciting in vivo model for a better understanding of its functioning and for development of new therapies. Today, one of the most robust humanized mouse model is achieved by injecting human hematopoietic stem cells (HSC) from fetal liver along with an implantation of autologous fetal thymic tissue. This model, called BLT, was shown to be able to support an optimal T cell reconstitution, maturation and selection. BLT mice are extensively used for many studies such as understanding HIV biology or in regenerative medicine. Indeed, our work used BLT mice on one hand to study the role of plasmacytoid dendritic cells (pDC) during the HIV infection and on the other hand to better understand the formation of teratomes from iPSCs in vivo. However, one of the biggest limitations of this technique is the procurement of the fetal tissue. Here we describe a new protocol to do humanized mice engrafted with human thymus pieces by using more accessible materials: human thymus obtained during cardiac surgery and cord blood HSC. Indeed, thymus is spontaneously removed during cardiac surgery in neonates and young children, thus it is an easy and ethical way to obtain this tissue. Those thymuses pieces were implanted in the quadriceps of a immunodeficient mice, after being put in culture. CCST mice (Cord blood and Cardiac Surgery Thymus) exhibited a significant engraftment of T-cells, compared to humanized mice without thymus. T-cells from both CCST and BLT mice showed a similar function as evaluated by proliferation assays upon PHA stimulation ex vivo and rejection of allogeneic leukemic cells lines in vivo. CCST mice were susceptible to HIV-1 infection via mucosal or intraperitoneal route, as shown by detectable viral load, HIV DNA and p24+ cells, at similar levels to those of BLT mice. Importantly, CCST mice displayed more effective ex vivo HIV-1-specific T-cell responses compared to BLT. Upon antiretroviral treatment, CCST mice, like BLT, were able to diminish the viral load. Our data suggest that CCST mice represent an alternative to the regular BLT mouse model. Those easy-to-access thymuses can be used to generate a large number of mice compared to fetal thymuses.

<p dir="ltr">Porcine reproductive and respiratory syndrome virus (PRRSV) is a devastating virus that is endemic to the swine industry. This virus has little direct effect on the dam but results in abortions, stillborn, and delivery of viremic piglets. PRRSV is unable to cross the swine placenta in early gestation but as gestation progresses, the placenta becomes permissible during late gestation. The mechanisms that allow the virus to cross the late gestation placenta are not well understood, but several theories have been presented regarding changes in placental morphology or enzymatic changes. Additionally, piglets who experience IUGR due to uterine crowding have been found to be more resistant to PRRSV infection, having lower viral levels than their normal litter mates. When vertical transmission from the dam to fetus occurs not only can the effects previously mentioned occur, but PRRSV is also known to cause suppression of maternal and fetal thyroid hormone. Thyroid hormone plays numerous roles in fetal development such as accretion of fetal mass, appetite regulation, and coincidently follows a similar increase trajectory to that of fetal growth during mid- to late-gestation. Consequently, any dysregulation of thyroid hormone has the potential to cause severe side-effects and may alter fetal growth. The relationship between thyroid hormone and fetal growth and development is not well understood. Chapter 2 investigates the potential cause-and-effect relationship between fetal growth and thyroid hormone through the induction of fetal hypothyroidism. Pregnant gilts (n=24) were given a sham treatment (CON; n=12) or treated with methimazole (MMI; n=12), a goitrogen capable of crossing the placenta. These gilts were then further subdivided across four gestational timepoints spanning mid- to late-gestation, these being days 55, 66, 76, and 86. Treatment started 21 days prior to these desired dates. Upon completion of treatment the gilts were humanely euthanized, and fetuses were extracted (resulting populations of n=174 MMI and n=166 CON) and fetal body and organ weights were recorded. Collected tissues included heart, liver, lung, kidneys, spleen, brain and thyroid. Fetuses were imaged in the left and right lateral recumbency for phenotypic analysis, including novel head measurements. Placental sample were also taken. Additionally fore- and hind limbs were taken from the centermost male and female from each litter so that radiographs could be taken to analyze bone growth. Statistical analysis of all phenotypic differences was carried out using a linear mixed effect model including gestational age and treatment as fixed effects and gilt as a random effect. The data revealed that the left and right phenotypic parameters are highly correlated (R2>0.9). Upon extraction, goiters were present in the MMI fetuses and there was a significant increase in both absolute and relative thyroid weights. Thus, the use of MMI during this period of gestation was successful in inducing hypothyroidism. Additionally, the MMI treated thyroids had a significant treatment by time interaction with 0.014g and 0.21g increase at day 55 and 66 respectively indicating reduced compensatory action within the fetal hypothalamic-pituitary-thyroid axis during this earliest period. Liver weight as a percentage of body weight decreased from 6.06% to 2.56% between days 55 and 86 in the CON group but, was significantly increased at all time points in response to MMI induced hypothyroidism (P<0.01). Thus, the in brain to liver weight ratio decreases over time, in MMI fetuses (P<0.05). While all other phenotypic parameters were significantly altered by gestation age, there was no significant impact of fetal hypothyroidism. This indicates that fetal thyroid hormone is not the driving factor for the exponential fetal growth seen in mid- to late-gestation. PRRSV virus is a complex and devastating virus to the swine industry, especially when it infects pregnant gilts and sows. PRRSV is unable to cross the swine placenta during mid-gestation but as gestation progresses the virus readily crosses the placenta and is able to infect piglets during this late gestation period. The mechanisms by which PRRSV crosses the highly restrictive porcine placenta are not clear. Additionally, piglets who experience intrauterine growth retardation experience lower virus levels than their normal counterparts. Chapter 3 investigates the changes in three genes of interest that we hypothesized, had the potential to fluctuate throughout gestation and facilitate PRRSV transfer, as well as the morphological changes that occur in the maternal-fetal interface through mid- to late-gestation and how these aspects may vary between IUGR and normal piglets. Placental samples were collected from pregnant gilts (n=12) equally divided across days 55, 66, 76, and 86 of gestation. Samples were taken of each fetus’s placenta adjacent to the umbilical cord. A portion of the sample was cut into 1 cm2 and placed into a mold with optimal cutting temperature media (OCT) for later cryo-sectioning and histology. The remaining portion had the fetal placenta peeled from the endometrium and flash frozen in liquid nitrogen for RNA extraction. A subset of samples was chosen based on fetus’s brain to liver weight ratios (n=96). From each litter two males and two females with the most extreme case of IUGR, based on z-scores, were chosen and the same was done for the two males and females with lowest brain to liver weight ratios, the later were classified as large for gestational age (LGA). 56 of the original 64 had acceptable levels of placental RNA for analysis. A total of 3 genes were chosen for analysis based on their function and previous literature. These included CD163, SIGLEC1 and IL-10. No significant up or down regulation was seen in any of the selected genes and there was no variation between IUGR and LGA fetuses. Additionally, placenta histology was conducted to evaluate populations of CD163 positive macrophages throughout the maternal fetal interface across mid- to late-gestation. Populations of CD163 positive macrophages were found on both the maternal and fetal sides of the maternal fetal interface at all timepoints. Collectively these results show there is no fluctuation in CD163, SIGLEC1, or IL-10 among timepoints or between IUGR and LGA fetuses. Additionally, the histology samples confirm the presence of resident populations of CD163 positive macrophages on maternal and fetal sides of the MFI. Collectively these results indicate that more research needs to be done to determine the underlying mechanisms of PRRSV transmission during late gestation.</p>