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Chromosome Abnormalities in Human Pregnancy Loss
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Tissue samples from spontaneous abortions must be of inner cell mass or fetally derived extra-embryonic origin to be of use in assessing the reason for the abortion. Indeed, as discussed in more detail below, contaminating maternal tissue is one of the most common, yet underappreciated, reasons for failure to identify the cause of the pregnancy loss (Figure 28.1a). The ideal tissue sample is a complete conceptus from an early loss (Figure 28.1b). This is not feasible in many instances, and fragments of fetal membranes with attached chorionic villi or simply villus fronds provide the next best options (Figure 28.1c and d). Such fragments can be obtained from samples where tissue from the conceptus has disintegrated or never formed. Later gestational age conceptions (post-12 weeks) may be represented by tissue from the extra-embryonic membranes, umbilical cord, placenta, or fetus proper. Importantly, the time between fetal demise and sample collection will affect tissue viability differentially. The embryo/fetus seems to be the first to die, followed by the umbilical cord, placenta, and finally the extra-embryonic membranes. This last tissue is therefore the most reliable in providing a fetal result.
Maternal Immunological Recognition of the Conceptus
Published in Gérard Chaouat, The Immunology of the Fetus, 2020
It must be stressed that the fetus itself is never in direct tissue contact with the mother and that the maternal and fetal blood streams remain independent. The allografted tissue in pregnancy is, therefore, primarily the fetal trophoblast in its diverse biological forms from the trophectoderm to the subpopulations of the mature placenta. There is an additional maternofetal interface at the level of the outermost extraembryonic membrane, which in the mouse and rat is the yolk sac. This membrane is exposed to the reconstituted uterine epithelium in the last third of gestation. Maternal immune recognition of the products of conception could, therefore, theoretically arise directly from the contact with fetal trophoblast and yolk sac and indirectly by transfer of soluble or particulate antigen from the fetus into the maternal circulation. Passage of maternal immunocompetent cells into the fetus, leading to antifetal immune responses, might also be considered as a form of immune recognition, although there is no convincing evidence for such transplacental traffic in rodents.1 There are, however, a few reported cases of graft-vs.-host reactions in human neonates that have been shown to contain maternal lymphoid cells.2
A comprehensive overview on utilizing electromagnetic fields in bone regenerative medicine
Published in Electromagnetic Biology and Medicine, 2019
Esmaeel Azadian, Bahar Arjmand, Zohreh Khodaii, Abdolreza Ardeshirylajimi
Stem cells are undifferentiated cells with remarkable potential for differentiation into specialized cells, under certain physiologic or experimental conditions, and the capacity for self-replication (Health, 2009). They can be categorized in three different groups (Figure 3): ESCs, fetal stem cells (FSCs), and adult stem cells (ASCs). ESCs are pluripotent cells extracted from the inner cell mass of the blastocyst and are responsible for creating ectoderm, endoderm, and mesoderm in human (Thomson et al., 1998). FSCs are divided into two types: the first type is multipotent and derived from tissue of the fetus which is usually obtained after an abortion, and the second type is pluripotent which derived from extra-embryonic membranes (Bongso and Lee, 2005; Moore et al., 2015). Also, they can be classified into five subclasses of haematopoietic, mesenchymal, endothelial, epithelial and neural (O’Donoghue and Fisk, 2004). ASCs or somatic stem cells are multipotent cells which are located in mature tissues and referred to by their tissue origin (such as mesenchymal stem cells, ASCs, etc.) and they are responsible for the maintenance and repair of the tissue in which they are found (Health, 2009).
Phytochemical screening, antioxidant, anti-inflammatory and antiangiogenic activities of Lophira procera A. Chev. (Ochnaceae) medicinal plant from Gabon
Published in Egyptian Journal of Basic and Applied Sciences, 2018
Rick-Leonid Ngoua-Meye-Misso, Cédric Sima-Obiang, Jean De La Croix Ndong, Joseph Privat Ondo, Felix Ovono Abessolo, Louis-Clément Obame-Engonga
Since the idea of tumor angiogenesis was suggested by Folkman [8], the blocking of tumor-induced angiogenesis was considered an attractive anticancer strategy because anti-angiogenic agents can be used independently of cancer types. The aqueous extract also showed strong antiangiogenic activity by the inhibition of blood vessel formations on chick embryo chorioallantoic membrane (CAM). Inhibition was dose dependent. In the range of doses tested, no dead embryos were recorded, indicating that the antiangiogenic effect observed was not due to the toxicity of the plant. This extract shows a stronger anti-angiogenic activity than the aqueous extracts of Oncoba welwitschii, Tetrorchidium oppositifolium, which showed a percentage inhibition of 83.334% at 500 μg/mL [14]. The CAM is an extraembryonic membrane whose main function is to ensure the exchange of gases and nutrients. Because of its large vascularity and ease of use, CAM is a popular research tool widely used to study glioma angiogenesis, growth, invasiveness and screening of anti-tumor drugs [28]. Therefore, according to the results, the aqueous extract of Lophira procera may have good inhibitory activity on tumor growth by blocking angiogenesis. Thus the use of Lophira procera in traditional medicine against breast cancer can be justified.