Non-invasive prenatal diagnosis by massively parallel sequencing of maternal plasma DNA

The presence of foetal DNA in the plasma of pregnant women has opened up new possibilities for non-invasive prenatal diagnosis. The use of circulating foetal DNA for the non-invasive prenatal detection of foetal chromosomal aneuploidies is challenging as foetal DNA represents a minor fraction of maternal plasma DNA. In 2007, it was shown that single molecule counting methods would allow the detection of the presence of a trisomic foetus, as long as enough molecules were counted. With the advent of massively parallel sequencing, millions or billions of DNA molecules can be readily counted. Using massively parallel sequencing, foetal trisomies 21, 13 and 18 have been detected from maternal plasma. Recently, large-scale clinical studies have validated the robustness of this approach for the prenatal detection of foetal chromosomal aneuploidies. A proof-of-concept study has also shown that a genome-wide genetic and mutational map of a foetus can be constructed from the maternal plasma DNA sequencing data. These developments suggest that the analysis of foetal DNA in maternal plasma would play an increasingly important role in future obstetrics practice. It is thus a priority that the ethical, social and legal issues regarding this technology be systematically studied.     

Novel approaches to manipulating foetal cells in the maternal circulation for non-invasive prenatal diagnosis of the unborn child

Due to the risks to the foetus with invasive prenatal diagnosis, non-invasive prenatal diagnosis (NIPD) is gaining tremendous interest but no reliable method that can be widely used has been developed to date. Manipulation of foetal cells and foetal cell-free genetic material in the maternal blood are two promising approaches being researched. The manipulation of foetal cells in the maternal circulation is more popular as it can provide complete genetic information of the foetus particularly the diagnosis of aneuploidies. However, the foetal cell numbers in the maternal circulation are small and their enrichment and ex vivo culture remain two major challenges for NIPD. Primitive foetal erythroblasts (pFEs) have been considered as a good potential candidate for early first trimester NIPD but their nature, properties and manipulation to provide adequate cell numbers remain a challenging task and several approaches need to be meticulously evaluated. In this review we describe the current status of NIPD and suggest some novel approaches in manipulating pFEs for future clinical application of NIPD. These novel approaches include (1) understanding the pFE enucleation process, (2) enriching pFE numbers by individual pick-up of pFEs from maternal blood using micromanipulation and microdroplet culture, (3) expansion of pFEs using mitogens and (4) decondensation of the pFE nucleus with histone deacetylase (HDAC) inhibitors followed by reprogramming using gene delivery protocols with/without small reprogramming molecules to improve reprogrammed pFE proliferation rates for successful NIPD.     

Protecting Future Children from In‐Utero Harm

The actions of pregnant women can cause harm to their future children. However, even if the possible harm is serious and likely to occur, the law will generally not intervene. A pregnant woman is an autonomous person who is entitled to make her own decisions. A fetus in‐utero has no legal right to protection. In striking contrast, the child, if born alive, may sue for injury in‐utero; and the child is entitled to be protected by being removed from her parents if necessary for her protection. Indeed, there is a legal obligation for health professionals to report suspected harm, and for authorities to protect the child's wellbeing. We ask whether such contradictory responses are justified. Should the law intervene where a pregnant woman's actions risk serious and preventable fetal injury? The argument for legal intervention to protect a fetus is sometimes linked to the concept of ‘fetal personhood’ and the moral status of the fetus. In this article we will suggest that even if the fetus is not regarded as a separate person, and does not have the legal or moral status of a child, indeed, even if the fetus is regarded as having no legal or moral status, there is an ethical and legal case for intervening to prevent serious harm to a future child. We examine the arguments for and against intervention on behalf of the future child, drawing on the example of excessive maternal alcohol intake.     

Ectogenesis and the case against the right to the death of the foetus

Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.     

胎肝细胞输注与全胚注射液治疗再生障碍性贫血的机理探讨

本文对胎肝细胞输注或全胚注射液治疗再生障碍性贫血的可能机理作了一些实验性探讨。研究结果表明: 1.胎肝细胞在培养或解体过程中释放某些刺激红系造血的因子,有利于已经损伤的造血功能的恢复。 2.对正常小鼠注射无细胞胎肝制剂或全胚注射液后,骨髓红系细胞的分裂指数明显升高,骨髓中粒/红比值趋于降低,反映了骨髓中红系细胞增生活跃的状态。 3.对正常小鼠注射无细胞胎肝制剂或全胚注射液后,外周血网织红细胞和腹腔巨噬细胞的吞噬指数趋于平行增高,其增高程度和持续时间随注射次数的增加而加强。 小鼠注射无细胞胎肝制剂或全胚注射液后,巨噬细胞吞噬指数的增加,反映了巨噬细胞激活,这种作用除了提高机体的非特异性免疫功能,增强机体的抵抗力外,还可能通过巨噬细胞的活化,直接或间接地调控机体红系细胞的增殖,因而,对巨噬细胞在造血调控中的作用以及它在再生障碍性贫血发病机理研究中的意义提出了讨论。     

Bioethics for clinicians: 12. Ethical dilemmas that arise in the care of pregnant women: rethinking "maternal-fetal conflicts".

When a pregnant woman makes a decision or acts in a manner that may be detrimental to the health and well-being of her fetus, her physician may be faced with an ethical dilemma. Is the physician''s primary duty to respect the woman''s autonomy, or to promote behaviour that may be in the best interest of the fetus? The controversial concept of "fetal rights" or the "fetus as a patient" contributes to the notion that the pregnant woman and her fetus are potential adversaries. However, Canadian law has upheld women''s right to life, liberty and security of the person and has not recognized fetal rights. If a woman is competent and refuses medical advice, her decision must be respected even if the physician believes that her fetus will suffer as a result. Coercion of the woman is not permissible no matter what appears to be in the best interest of the fetus.     

Endocrine regulation of phosphorus and calcium metabolism during pregnancy in domestic ruminants

In pregnant domestic ruminants (cows, ewes, goats) foetal plasma calcium and inorganic phosphorus concentrations are higher than those measured in the dam. The foetus regulates its own calcaemia and phosphataemia. Changes in maternal plasma calcium levels have no significant effect on foetal calcaemia. Calcium and phosphorus are transported from the dam to the foetus according to a one-way process, the transport from the foetus to the dam being negligible. An important part of the calcium transferred to the foetus comes from the maternal skeleton. The true molecular mechanisms involved in placental transport of calcium are still unknown. This is an active transport, stimulated by vitamin D metabolites (of maternal, foetal or placental origin) and maternal prolactin. Maternal calcitonin protects the skeleton of the pregnant (and lactating) female ruminant against excessive demineralization, partly by modulating placental transport of calcium during periods of intense mineralization of foetal skeleton.     

Ethics and Embryo/Foetus Research

Research with embryos and foetuses raise moral problems. In this article the origins of these moral intuitions are analyzed and discussed at four levels: moral problems regarding the treatment of the foetus and the mother animal; ethical problems experienced by the moral actor (researcher); ethical problems related to a justification based upon a balance between means and goals; and ethical problems raised by society.     

Ethics and Embryo/Foetus Research

Research with embryos and foetuses raise moral problems. In this article the origins of these moral intuitions are analyzed and discussed at four levels: moral problems regarding the treatment of the foetus and the mother animal; ethical problems experienced by the moral actor (researcher); ethical problems related to a justification based upon a balance between means and goals; and ethical problems raised by society.     

Enzymic basis of deranged foetal flavin-nucleotide metabolism consequent on immunoneutralization of maternal riboflavin carrier protein in the pregnant rat.

A comparison of the kinetic and other parameters of enzymes of flavin-nucleotide metabolism in the whole foetus vis-à-vis the maternal liver in the pregnant rat revealed relatively lower activities of foetal flavokinase and FAD pyrophosphorylase. Passive immunoneutralization of the maternal riboflavin carrier protein suppresses foetal FAD pyrophosphorylase rather selectively. Additionally, although the activities of foetal nucleotide pyrophosphatase and FMN phosphatase were unchanged owing to immunoneutralization, higher activities of these enzymes in the whole foetus as compared with the maternal liver may be responsible for the drastic depletion of FAD levels that precipitates foetal degeneration.     

A case of Cushing's syndrome in pregnancy

Cushing's syndrome (also known as hypercortisolemia) is rare in pregnant women due to the menstrual disturbances and infertility in women with hypercortisolism. A diagnosis of pathological hypercortisolism in pregnant women is often difficult as some symptoms of the disease may be associated with a complicated pregnancy. Hypercortisolemia leads to serious complications for mother and foetus, and is associated with premature labour and high foetal mortality. Hormonal and radiological diagnostics in pregnancy are limited. The results of hormonal measurements and dynamic tests are difficult to interpret due to the physiological changes in the hypothalamo-pituitaryadrenal axis connected with pregnancy. The optimal time and method of treatment should be chosen cautiously case by case because of the possibility of maternal and foetal complications. In this paper, we present a case of Cushing's syndrome secondary to adrenal adenoma in which the diagnosis was made in the 22(nd) week of pregnancy. Due to the advanced gestational status and mild symptoms of hypercortisolism, only symptomatic treatment was introduced. The patient was under continuous obstetric and endocrinological care. At 35 weeks of gestation, the pregnancy was terminated by emergency caesarean section because of premature detachment of the placenta. A male infant weighing 2,450 g was delivered; neither adrenal insufficiency in the child nor hypercortisolemia complications in the mother were observed.     

Metallothionein synthesis in foetal, neonatal and maternal rat liver

The synthesis of hepatic metallothionein relative to other cytosol proteins was measured by [35S]cysteine incorporation in foetal, neonatal and pregnant rats. The relative rate of hepatic metallothionein synthesis reached a maximum in foetal liver on days 18-21 of gestation. Metallothionein synthesis then declined until weaning, when adult levels were established. The rate of metallothionein synthesis was greater in pregnant rats at term than in nulliparous rats. To determine if circulating inducing agents could play a role in the regulation of metallothionein synthesis in foetal liver we treated pregnant rats with inducers at a time prior to the normal rise in foetal liver metallothionein synthesis. Injections of copper, cadmium or hydrocortisone to 17-day-pregnant dams failed to induce foetal metallothionein synthesis. In contrast, zinc injection to the dam was an effective inducer in the foetuses. Maternal laparotomy (performed to expose the foetus for direct injection of inducers) induced foetal metallothionein synthesis. Metallothionein synthesis in the livers of 17-day-gestation dams was induced by all metal injections and laparotomy but, surprisingly, not by hydrocortisone injection. Maternal adrenalectomy did not influence the subsequent normal elevation in foetal or maternal metallothionein synthesis. These results, in conjunction with previous reports, suggest that mobilization of zinc in serum during late gestation may regulate foetal and maternal changes in metallothionein synthesis.     

TWO STALEMATES IN THE PHILOSOPHICAL DEBATE ABOUT ABORTION AND WHY THEY CANNOT BE RESOLVED USING ANALOGICAL ARGUMENTS

Philosophical debate about the ethics of abortion has reached stalemate on two key issues. First, the claim that foetuses have moral standing that entitles them to protections for their lives has been neither convincingly established nor refuted. Second, the question of a pregnant woman's obligation to allow the gestating foetus the use of her body has not been resolved. Both issues are deadlocked because philosophers addressing them invariably rely on intuitions and analogies, and such arguments have weaknesses that make them unfit for resolving the abortion issue. Analogical arguments work by building a kind of consensus, and such a consensus is virtually unimaginable because (1) intuitions are revisable, and in the abortion debate there is great motive to revise them, (2) one's position on abortion influences judgments about other issues, making it difficult to leverage intuitions about other ethical questions into changing peoples' minds about abortion, and (3) the extent of shared values in the abortion debate is overstated. Arguments by analogy rely on an assumption of the commensurability of moral worldviews. But the abortion debate is currently unfolding in a context of genuinely incommensurable moral worldviews. The article ends by arguing that the default position must be to permit abortion as a consequence of the freedom of conscience protected in liberal societies.     

Reduction of biliverdin and placental transfer of bilirubin and biliverdin in the pregnant guinea pig.

Biliverdin was reduced to bilirubin in pregnant and foetal guinea pigs, and the 100000 g supernatant from homogenates of foetal liver, placenta and maternal liver showed high biliverdin reductase activity. The placental transport of unconjugated bilirubin and biliverdin was compared by injecting unlabelled and radiolabelled pigments into the foetal or maternal circulation and analysing blood collected from the opposite side of the placenta. Injected bilirubin crossed the placenta from foetus to mother and vice versa, but injected biliverdin did not appear to cross without prior reduction to bilirubin. The guinea-pig placenta is apparently more permeable to bilirubin than biliverdin. Reduction of biliverdin to bilirubin in the foetus may, therefore, be essential for efficient elimination of haem catabolites from the foetus in placental mammals.     

Altruistic surrogacy and informed consent

A crucial premise in many recent arguments against the moral permissibility of surrogate motherhood arrangements is the claim that a woman cannot autonomously consent to gestating and relinquishing a child to another couple, because she cannot be fully informed about what her future emotional responses will be to the foetus developing within her, and to the giving up of the newborn infant to its social parents. When conjoined with some moral principle about the justifiable limits on the ways others can be expected to exercise their autonomy on our behalf, this claim is often taken to establish that various forms of surrogate motherhood arrangements are morally wrong. In this paper I want to show that there is a serious non sequitur in this kind of argument. That is, I want to show that even if women cannot in fact have this kind of information about what their future emotional responses to pregnancy and relinquishment will be, nothing follows about the wrongness or otherwise of surrogacy. For, when we consider what counts as informed consent in the context of other important ventures with uncertain consequences, it becomes clear that informed consent does not require having this kind of information about one's future emotional states. In putting these arguments, I also hope to clarify some of the connections which might be thought to hold between informed consent and autonomous decision-making generally.     

Normal fluctuations in the concentration of corticosteroid and adrenocorticotrophin in the plasma of foetal and pregnant sheep.

Changes in the concentration of adrenocorticotrophin and corticosteroid in the plasma of pregnant and foetal sheep have been followed at different times of day. Wide fluctuations were seen in the concentrations of both in the foetus and ewe, although no evidence for a diurnal rhythm in the ewe was obtained. The foetal plasma adrenocorticotrophin was higher at 07.00-11.00 h than at 21.00-01.00 h, but no corticosteroid rhythm was observed. A consistently close relationship between maternal and foetal hormone concentrations was not observed. The diurnal rhythm in adrenocorticotrophin concentration in the foetus is discussed in relation to rhythms in indicators of central nervous activity.     

Consumption of a high-salt diet by ewes during pregnancy alters nephrogenesis in 5-month-old offspring

Maternal nutrition during pregnancy can affect kidney development in the foetus, which may lead to adverse consequences in the mature kidney. It was expected that high-salt intake by pregnant ewes would lead to a reduction in foetal glomerular number but that the ovine kidney would adapt to maintain homoeostasis, in part by increasing the size of each glomerulus. Merino ewes that were fed either a control (1.5% NaCl) or high-salt (10.5% NaCl) diet during pregnancy, as well as their 5-month-old offspring, were subjected to a dietary salt challenge, and glomerular number and size and sodium excretion were measured. The high-salt offspring had 20% fewer glomeruli compared with the control offspring (P < 0.001), but they also had larger glomerular radii compared with the control offspring (P < 0.001). Consequently, the cross-sectional area of glomeruli was 18% larger in the high-salt offspring than in the control offspring (P < 0.05). There was no difference in the daily urinary sodium excretion between the two offspring groups (P > 0.05), although the high-salt offspring produced urine with a higher concentration of sodium. Our results demonstrated that maternal high-salt intake during pregnancy affected foetal nephrogenesis, altering glomerular number at birth. However, the ability to concentrate and excrete salt was not compromised, which indicates that the kidney was able to adapt to the reduction in the number of glomeruli.     

'You don't make genetic test decisions from one day to the next'--using time to preserve moral space

The part played by time in ethics is often taken for granted, yet time is essential to moral decision making. This paper looks at time in ethical decisions about having a genetic test. We use a patient-centred approach, combining empirical research methods with normative ethical analysis to investigate the patients' experience of time in (i) prenatal testing of a foetus for a genetic condition, (ii) predictive or diagnostic testing for breast and colon cancer, or (iii) testing for Huntington's disease (HD). We found that participants often manipulated their experience of time, either using a stepwise process of microdecisions to extend it or, under the time pressure of pregnancy, changing their temporal 'depth of field'. We discuss the implications of these strategies for normative concepts of moral agency, and for clinical ethics.     

Human Non-persons, Feticide, and the Erosion of Dignity

Feticide, the practice of terminating the life of an otherwise viable fetus in utero, has become an increasingly common practice in obstetric centres around the globe, a concomitant of antenatal screening technologies. This paper examines this expanding practice in light of the concept of human dignity. Although it is assumed from the outset that even viable human fetuses are not persons and as such do not enjoy full membership in the moral community, it is argued that the fact that these are nevertheless human fetuses affords them prima facie moral status. Thus even those who accept a liberal position with regard to therapeutic abortion, should be concerned about these more recent developments. Indeed, how we treat viable human fetuses has implications for our prospective treatment of other human non-persons and could undermine the common human dignity we all share.     

Effects of maternal nutrient restriction during early or mid-gestation without realimentation on maternal physiology and foetal growth and development in beef cattle

The aim of this study is to determine the effects of early and mid-gestation nutrient restriction on maternal metabolites and foetal growth. Primiparous Angus cows were synchronized and inseminated with semen from one sire. Dietary treatments were: control to gain 1 kg/week (CON) or 0.55% maintenance energy and CP requirements (nutrient restricted; NR). A subset of dams was fed NR (n=8) or CON (n=8) from days 30 to 110 of gestation. Another group was fed CON (n=8), days 30 to 190; NR (n=7), days 30 to 110 followed by CON days 110 to 190; or CON, (n=7) days 30 to 110 followed by NR days 110 to 190. Cows were harvested at days 110 or 190 of gestation, when foetal measurements and samples were collected. Cows that were NR during days 30 to 110 or 110 to 190 of gestation lost significant BW and body condition score (P<0.001), this was associated with reduced plasma glucose during NR (P<0.002). Foetal weights, empty foetal weights, abdominal and thoracic circumferences were all reduced (P<0.03) in day 110 NR animals. Foetal perirenal adipose as a percentage of empty foetal weight was increased (P=0.01) in NR day 110 female foetuses compared with CON foetus. Maternal serum triglycerides at day 110 of gestation were decreased (P<0.05) in NR dams, whereas foetal serum triglycerides were increased (P<0.05) in response to maternal NR. Foetal weights tended to be reduced (P=0.08) in NR/CON and CON/NR v. CON/CON cattle at day 190 of gestation. Empty foetal weights, abdominal and thoracic circumferences were reduced (P⩽0.03) in NR/CON and CON/NR v. CON/CON cattle. Brain weight as a percentage of empty foetal weight was increased (P<0.001) in NR/CON and CON/NR v. CON/CON cattle. Foetal perirenal adipose as a percentage of empty foetal weight was increased (P=0.003) in NR/CON and CON/NR v. CON/CON cattle. Maternal serum triglycerides at day 190 of gestation were decreased (P<0.05) in association with maternal NR. Foetal serum triglycerides at day 190 of gestation were increased (P<0.05) in response to maternal NR during early gestation but decreased by NR in mid gestation compared with CON foetuses. The data show that maternal nutrient restriction during early or mid-gestation cause’s asymmetrical foetal growth restriction, regardless if the restriction is preceded or followed by a period of non-restriction.