ABSTRACT
A growing number of people desire ART with cryopreserved donor oocytes. The allocation of these oocytes to couples and mothers to be is a 2-fold process. The first step is to select a pool ...of recipients. The second step is to decide who should be treated first. Prioritizing recipients is critical in settings where demand outstrips supply. So far, the issue of how to fairly allocate cryopreserved donor oocytes has been poorly addressed. Our ethical analysis aims to support clinics involved in allocation decisions by formulating criteria for recipient selection irrespective of supply (Part I) and recipient prioritization in case supply is limited (Part II). Relevant criteria for recipient selection are: a need for treatment to experience parenthood; a reasonable chance for successful treatment; the ability to safely undergo an oocyte donation pregnancy; and the ability to establish a stable and loving relationship with the child. Recipients eligible for priority include those who: have limited time left for treatment; have not yet experienced parenthood; did not undergo previous treatment with cryopreserved donor oocytes; and contributed to the supply of donor oocytes by bringing a donor to the bank. While selection criteria function as a threshold principle, we argue that the different prioritization criteria should be carefully balanced. Since specifying and balancing the allocation criteria undoubtedly raises a moral dispute, a fair and legitimate allocation process is warranted (Part III). We argue that allocation decisions should be made by a multidisciplinary committee, staffed by relevant experts with a variety of perspectives. Furthermore, the committees’ reasoning behind decisions should be transparent and accessible to those affected: clinicians, donors, recipients and children born from treatment. Insight into the reasons that underpin allocation decisions allows these stakeholders to understand, review and challenge decisions, which is also known as accountability for reasonableness.
Abstract
STUDY QUESTION
What are the moral considerations held by donors, recipients and professionals towards the ethical aspects of the intake and distribution of donor bank oocytes for third-party ...assisted reproduction?
SUMMARY ANSWER
Interviews with oocyte donors, oocyte recipients and professionals demonstrate a protective attitude towards the welfare of the donor and the future child.
WHAT IS KNOWN ALREADY
The scarcity of donor oocytes challenges the approach towards the many ethical aspects that arise in establishing and operating an oocyte bank for third-party assisted reproduction. Including experiences and moral considerations originating from practice provides useful insight on how to overcome these challenges.
STUDY DESIGN, SIZE, DURATION
The project was set-up as a qualitative interview study and took place between October 2016 and August 2017.
PARTICIPANTS/MATERIALS, SETTING, METHODS
We conducted 25 semi-structured interviews with professionals engaged in the practice of oocyte banking (n = 10), recipients of donor oocytes (n = 7) and oocyte donors (n = 8). Key themes were formulated by means of a thematic analysis.
MAIN RESULTS AND THE ROLE OF CHANCE
Based on the interviews, we formulated four main themes describing stakeholders' views regarding the ethical aspects of the intake and distribution of donor bank oocytes. First, respondents articulated that when selecting donors and recipients, healthcare workers should prevent donors from making a wrong decision and safeguard the future child's well-being by minimizing health risks and selecting recipients based on their parental capabilities. Second, they proposed to provide a reasonable compensation and to increase societal awareness on the scarcity of donor oocytes to diminish barriers for donors. Third, respondents considered the prioritization of recipients in case of scarcity a difficult choice, because they are all dependent on donor oocytes to fulfil their wish for a child. They emphasized that treatment attempts should be limited, but at least include one embryo transfer. Fourth and finally, the importance of good governance of oocyte banks was mentioned, including a homogenous policy and the facilitation of exchange of experiences between oocyte banks.
LIMITATIONS, REASONS FOR CAUTION
The possibility of selection bias exists, because we interviewed donors and recipients who were selected according to the criteria currently employed in the clinics.
WIDER IMPLICATIONS OF THE FINDINGS
Respondents' moral considerations regarding the ethical aspects of the intake and distribution of donor oocytes demonstrate a protective attitude towards the welfare of the donor and the future child. At the same time, respondents also questioned whether such a (highly) protective attitude was justified. This finding may indicate there is room for reconsidering strategies for the collection and distribution of donor bank oocytes.
STUDY FUNDING/COMPETING INTEREST(s)
This study was funded by ZonMw: The Dutch Organization for Health Research and Development (Grant number 70-73000-98-200). A.M.E.B. and B.C.J.M.F. are the initiators of the UMC Utrecht oocyte bank. J.J.P.M.P. is the director of the MCK Fertility Centre. IMC is working as a gynaecologist at the AMC Amsterdam oocyte bank. During the most recent 5-year period, BCJM Fauser has received fees or grant support from the following organizations (in alphabetic order): Actavis/Watson/Uteron, Controversies in Obstetrics & Gynaecologist (COGI), Dutch Heart Foundation, Dutch Medical Research Counsel (ZonMW), Euroscreen/Ogeda, Ferring, London Womens Clinic (LWC), Merck Serono (GFI), Myovant, Netherland Genomic Initiative (NGI), OvaScience, Pantharei Bioscience, PregLem/Gedeon Richter/Finox, Reproductive Biomedicine Online (RBMO), Roche, Teva and World Health Organization (WHO). The authors have no further competing interests to declare.
TRIAL REGISTRATION NUMBER
N/A.
In most models of DNA replication, Watson-Crick hydrogen bonding drives the incorporation of nucleotides into the new strand of DNA and maintains the complementarity of bases with the template ...strand. Studies with nonpolar analogues of thymine and adenine, however, have shown that replication is still efficient in the absence of hydrogen bonds. The replication of base pairs might also be influenced by steric exclusion, whereby inserted nucleotides need to be the correct size and shape to fit the active site against a template base,. A simple steric-exclusion model may not require Watson-Crick hydrogen bonding to explain the fidelity of replication, nor should canonical purine and pyrimidine shapes be necessary for enzymatic synthesis of a base pair if each can fit into the DNA double helix without steric strain. Here we test this idea by using a pyrene nucleoside triphosphate (dPTP) in which the fluorescent 'base' is nearly as large as an entire Watson-Crick base pair. We show that the non-hydrogen-bonding dPTP is efficiently and specifically inserted by DNA polymerases opposite sites that lack DNA bases. The efficiency of this process approaches that of a natural base pair and the specificity is 102-104-fold. We use these properties to sequence abasic lesions in DNA, which are a common form of DNA damage in vivo. In addition to their application in identifying such genetic lesions, our results show that neither hydrogen bonds nor purine and pyrimidine structures are required to form a base pair with high efficiency and selectivity. These findings confirm that steric complementarity is an important factor in the fidelity of DNA synthesis.
Supernova 1978K is one of the oldest-known examples of the class of Type IIn supernovae that show evidence for strong interaction between the blast wave and a dense, pre-existing circumstellar ...medium. Here we report detections of SN 1978K at both 34 GHz and 94 GHz, making it only the third extragalactic supernova (after SN 1987A and SN 1996cr) to be detected at late-times at these frequencies. We find SN 1978K to be >400 times more luminous than SN 1987A at millimetre wavelengths in spite of the roughly nine year difference in ages, highlighting the risk in adopting SN 1987A as a template for the evolution of core-collapse supernovae in general. Additionally, from new VLBI observations at 8.4 GHz, we measure a deconvolved diameter for SN 1978K of ~5 milli-arcsec, and a corresponding average expansion velocity of <1500 km s-1. These observations provide independent evidence of an extremely dense circumstellar medium surrounding the progenitor star.
DNA polymerase enzymes process their natural substrates with very high specificity. Yet recent experiments have shown that these enzymes can also process DNA in which the backbone or bases are ...modified to a surprising degree. Such experiments have important implications in understanding the mechanisms of DNA replication, and suggest important biotechnological uses as well.
Quenched autoligation (QUAL) probes are a class of self-reacting nucleic acid probes that give strong fluorescence signal in the presence of fully complementary RNAs and selectivity against single ...nucleotide differences in solution. Here, we describe experiments designed to test whether QUAL probes can discriminate between bacterial species by the detection of small differences in their 16S rRNA sequences. Probes were introduced into live cells using small amounts of detergent, thus eliminating the need for fixation, and fluorescence signal was monitored both by microscopy and by flow cytometry without any washing steps. The effects of probe length, modified backbone, probe concentration and growth state of the bacteria were investigated. The data demonstrate specific fluorescence discrimination between three closely related bacteria, Escherichia coli, Salmonella enterica and Pseudomonas putida, based on single nucleotide differences in their 16S rRNA. Discrimination was possible with cells in mid-log phase or in lag phase. These results suggest that QUAL probes may be useful for rapid identification of microorganisms in laboratory and clinical settings.
We report on the application of a new class of oligonucleotide reporter probes, QUAL probes, that "light up" when a nucleophilic phosphorothioate probe binds adjacent to a dabsyl-quenched probe. ...These self-ligating DNA probes were used for sequence-specific detection of 16S rRNA in Escherichia coli cells. Strong fluorescence was observed only when the phosphorothioate and quenched dabsyl probes bind side-by-side on a 16S rRNA target. The results demonstrate the use of QUAL probes to detect specific RNA sequences in bacterial cells without enzymes and without washing steps.
We describe the synthesis and study of multicolor quenched autoligating (QUAL) probes for identification and discrimination of closely related RNA and DNA sequences in solution and in bacteria. In ...these probes, a dabsyl quencher doubles as an activator in the oligonucleotide-joining reaction. The oligonucleotides remain dark until they bind at adjacent sites, and "light up" on nucleophilic displacement of the dabsyl probe by the phosphorothioate probe. Four fluorescent dye conjugates were prepared and tested with probes and targets that differ by one nucleotide. Experiments on polymer beads show clear color-based discrimination of DNAs added in solution. Two-color quenched probe pairs were then tested in the discrimination of 16S rRNA sequences in Escherichia coli. Single nucleotide resolution was achieved in the cells with green/red QUAL probes, allowing identification of a one-base sequencing error in the 16S rRNA database. Finally, QUAL probes were successfully applied in live bacterial cells. The method requires only incubation followed by fluorescence imaging, and requires no enzymes, added reagents, cross-linking, fixing, or washes. Because probes must bind side-by-side to generate signal, there is little or no interference from unintended protein binding, which can occur with other probe types. The results suggest that QUAL probes may be of general use in the detection and identification of sequences in solution, on microarrays, and in microorganisms.