SEARCH · Search PubMed
Results for “Genetics and Reproduction”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Procreation after death or mental incompetence: medical advance or technology gone awry?
OBJECTIVE: To review our experience with semen retrieval in men who are incompetent or dead and to formulate general medical, legal, and ethical guidelines for practitioners. DESIGN: Case series and literature review. SETTING: Academic. PATIENT(S): Seven incompetent or neurologically dead individuals in whom sperm retrieval was requested. INTERVENTION(S): Electroejaculation. RESULT(S): Seminal emission was induced in the two men who underwent electroejaculation. Sperm suitable for cryopreservation was obtained in one of these men. Review of the legal and ethical implications of such procedures led to development of general guidelines for determining whether gamete retrieval should be performed when requested. Issues of procreational autonomy, consideration of the decedent's wishes, and assurance of the well-being of any new life created were considered most strongly in the formation of these guidelines. CONCLUSION(S): Although the retrieval of sperm from deceased or incompetent individuals may be achieved readily, it is incumbent upon the practitioner to consider the legal and moral implications of these procedures before proceeding.
Embryo number for transfer should not be strictly regulated.
Explore the source record for details and available documents.
Preimplantation genetic diagnosis of Marfan syndrome with the use of fluorescent polymerase chain reaction and the Automated Laser Fluorescence DNA Sequencer.
OBJECTIVE: To develop and apply clinical preimplantation genetic diagnosis (PGD) for Marfan syndrome. DESIGN: Case report. SETTING: Centers for medical genetics and reproductive medicine in university hospitals. PATIENT(S): One couple in which the husband was affected with Marfan syndrome. INTERVENTION(S): The couple underwent three intracytoplasmic sperm injection cycles. MAIN OUTCOME MEASURE(S): The correct diagnosis was obtained for embryos in three PGD cycles. RESULT(S): Although all the PGD cycles were followed by ET, no pregnancy ensued. CONCLUSION(S): This assay can provide a reliable and accurate preimplantation diagnosis of Marfan syndrome.
Assisted reproduction for couples infected with the human immunodeficiency virus type 1.
Explore the source record for details and available documents.
Developing public policy on assisted reproductive technologies: reflections on the work of the New York State Task Force on Life and the Law.
Explore the source record for details and available documents.
A general mathematical model for sex allocation.
A general matrix equation for evolutionary equilibrium of sex allocation is derived. The equation allows calculation of ESS values of behavioural parameters in sex allocation models, and provides a conceptual framework in which such models can be viewed. A careful discussion is given of a number of examples from the literature. An attempt is made to clarify the assumptions behind different models and relate different results which have been obtained.
Physiology of mating in three yeasts.
Explore the source record for details and available documents.
White-opaque switching in Candida albicans is controlled by mating-type locus homeodomain proteins and allows efficient mating.
Discovered over a decade ago, white-opaque switching in the human fungal pathogen Candida albicans is an alternation between two quasistable, heritable transcriptional states. Here, we show that white-opaque switching and sexual mating are both controlled by mating type locus homeodomain proteins and that opaque cells mate approximately 10(6) times more efficiently than do white cells. These results show that opaque cells are a mating-competent form of C. albicans and that this pathogen undergoes a white-to-opaque switch as a critical step in the mating process. As white cells are generally more robust in a mammalian host than are opaque cells, this strategy allows the organism to survive the rigors of life within a mammalian host, yet generate mating-competent cells.
The cloning debate and the cycle of evolution.
Explore the source record for details and available documents.
Reproductive health and human rights.
Explore the source record for details and available documents.
Implications of genetic testing for insurance in the UK.
Explore the source record for details and available documents.
Cabinet reshuffle demotes British science.
Explore the source record for details and available documents.
"Iceland Inc."?: On the ethics of commercial population genomics.
A detailed analysis of the Icelandic commercial population-wide genomics database project of deCODE Genetics was performed for the purpose of providing ethics insights into public/private efforts to develop genetic databases. This analysis examines the moral differences between the general case of governmental collection of medical data for public health purposes and the centralized collection planned in Iceland. Both the process of developing the database and its design vary in significant ways from typical government data collection and analysis activities. Because of these differences, the database may serve the interests of deCODE more than it serves the interests of the public, undermining the claim that presumed consent for this data collection and its proprietary use is ethical. We believe that there is an evolving consensus that informed consent of participants must be secured for population-based genetics databases and research. The Iceland model provides an informative counterexample that holds key ethics lessons for similar ventures.
Unaltered meiotic chromosome segregation in Drosophila melanogaster raised on a 5% quercetin diet.
Flavonoid plant pigments are an integral part of the human diet. Although potentially negative mitotic effects of flavonoids have been observed in model organisms, investigation into meiotic effects of flavonoids has been neglected. As flavonoids affect cell signalling and DNA replication, and because the flavonoid content of the human food supply is being increased, determining the effects of flavonoids on meiotic fidelity is important. Here, the effect of the human food supply's most prevalent flavonoid, quercetin, on the level of meiotic recombination and the amount of X and 4th chromosome non-disjunction in Drosophila melanogaster females was determined. This model organism was chosen since Drosophila melanogaster and Homo sapiens share a remarkable number of commonalities in the meiotic processes of oogenesis and because genetic techniques allow a detailed analysis of meiotic processes in Drosophila. No significant effect on either non-disjunction levels or the percentage distribution of exchange bivalents was observed. A significant effect was observed on the number of offspring; F1 and F2 generations of flies raised on a quercetin diet produced over 10% more progeny than flies raised on a control diet. In this investigation, high quercetin consumption by Drosophila melanogaster females did not pose a threat to meiotic fidelity.
Simulation of the evolution of genomic complexity.
A general evolutionary trend is the generation of organisms of increasing complexity, notwithstanding that reduction and simplification phenomena do occur in the evolutionary process. This paper proposes an evolutionary model incorporating the mechanisms of gene amplification and deletion. The evolutionary process leading to genomic complexity and the coexistence of simpler organisms with complicated ones were both simulated using the proposed model. The model was also used to investigate the influence of various factors on the evolution of complexity. The simulations indicated that the evolution of complexity is largely influenced by adaptation to complicated environments. Nevertheless, complex organisms require relatively more resources for survival and replication, which limits the on going tendency towards complexity. Moreover, the analysis showed that if the environment varies rapidly and the profit obtained from complexity is greater than the resources consumed, selection will tend to favor complexity. However, high living cost will tend to limit the trend of complexity and if the environment is relatively stable, reduction and simplification will become the dominant trends.
Mutations and polymorphisms in gonadotropin genes.
Mutations in gonadotropin genes are extremely rare. Only one case of inactivating human luteinizing hormone (LH) beta mutation exists in the literature, a male with absence of Leydig cells, lack of spontaneous puberty and infertility. A total of four cases of inactivating mutation of the follicle-stimulating hormone beta (FSHbeta) gene (two female and two male) are known. The phenotype of the women was primary amenorrhea and absence of follicular maturation, the men were azoospermic. In addition, a common genetic variant (v) of LH was recently discovered. It is caused by two point mutations in the LH beta-subunit gene, resulting in amino acid alterations: Trp8 --> Arg and Ile15 --> Thr. In addition, the latter change introduces an extra glycosylation signal for oligosaccharide attachment to Asn13. The v-LHbeta allele has a carrier frequency ranging from 0 to > 50% in various populations. The variant LH molecule has increased intrinsic bioactivity in vitro, but decreased circulatory half-life in vivo, and the v-LHbeta promoter is about 50% more active in cell line transfections than that of wild-type (wt) LH. These differences in LH synthesis and action in individuals homo- or heterozygous for the v-LH allele are reflected by altered disposition to pathologies of pituitary-gonadal function, such as delayed puberty, polycystic ovarian syndrome and infertility.