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Biomedical subjects

A McWhinnie

Publications and source records attributed to A McWhinnie.

17 recordsLinked to original sources
PubMed2002

Further polymorphism of the MICA gene.

The MHC class I chain-related (MIC) gene family constitutes an interesting genetic group that is related to major histocompatibility complex (MHC) class I genes and is located within the MHC. The MIC gene products, MICA and MICB, have similar structures to HLA class I molecules. So far over 50 MICA alleles have been reported, which suggests that this genetic system is highly polymorphic. In order to investigate further the extent of MICA polymorphism we have studied exons 2-5 of the MICA gene in over 200 homozygous and heterozygous cell lines. Altogether we have identified 11 new MICA alleles and report 13 new nucleotide variations, one in exon 2, four in exon 3, four in exon 4, two in intron 1, one in intron 4 and one (a deletion) in exon 4. Eight of the 10 exonic variations are non-synonymous. The deletion in exon 4 leads to a frame-shift mutation and the introduction of a repeat of 12 leucine residues encoded by the microsatellite in exon 5. This study provides further evidence that the MICA gene is highly polymorphic. In contrast to MHC class I molecules, the polymorphic sites in MICA are predominantly within the alpha2 and alpha3 domains. The distribution of synonymous and non-synonymous substitutions suggests that there is selection for the polymorphic positions, which therefore define potential functional sites in the protein. We were also able to determine the association between MICA and HLA-B alleles in a number of homozygous cell lines bearing extended haplotypes.

Alleles↗
PubMed2001

HLA-B typing by reference strand mediated conformation analysis using a capillary-based semiautomated genetic analyzer.

The application of reference strand conformation analysis (RSCA) to HLA-A typing using the ABI PRISM 310 capillary based genetic analyzer has recently been described. This study outlines the development and validation of capillary RSCA for HLA-B typing. Mobility values for 93 HLA-B alleles were defined following electrophoresis of known controls through the system. Three fluorescently labelled references, labelled with three different dyes can be electrophoresed simultaneously. The technique was validated by comparing results from 296 cord blood donors with those obtained using reverse SSO. Following capillary RSCA 14.5% of samples required confirmatory typing, compared with a repeat rate of 5.1% following reverse SSO. In samples where no other typing was necessary there was 100% correlation between the two methods. Capillary RSCA for HLA-B typing is quick, easy to implement, and with the introduction of new FLRs and gel matrices has the potential to evolve into a high resolution typing method.

Alleles↗
PubMed2001

Cord blood transplants: early recovery of neutrophils from co-transplanted sibling haploidentical progenitor cells and lack of engraftment of cultured cord blood cells, as ascertained by analysis of DNA polymorphisms.

The number of infused cells is a very important factor in cord blood transplant (CBT) engraftment. Prior ex vivo expansion of aliquots of transplanted cord blood (CB) units is being investigated as a procedure to increase engraftment potential, but results are difficult to evaluate due to a lack of markers for assessing the contribution of expanded cells. We transplanted five patients, infusing the best available CB unit and cells from a second donor simultaneously. In two patients, these cells were obtained from another frozen CB unit by CD34(+)positive selection and culture expansion; the other three patients received uncultured highly purified haploidentical CD34(+) cells. The first two patients had DNA from the culture expanded CB cells detected only for a few days around day +11 when the absolute neutrophil count (ANC) was >200/microl; thereafter and when the ANC was <500/microl, only donor DNA from the uncultured CB was detected. For the other three patients, DNA analysis showed early and transient granulocyte engraftment of haploidentical cells, progressively replaced by the CB-derived granulocytes. We concluded that: (1) simultaneous infusion of lymphocyte-depleted HLA highly mismatched haematopoietic progenitor cells has not produced unfavourable effects for CBT; (2) the double transplant model is suitable for evaluating the engraftment potential of ex vivocultured CB cells in the clinical setting; (3) the culture conditions used did not result in early recovery of ANC; and (4) co-transplantation of purified uncultured HLA haploidentical CD34(+) cells may reduce the time of neutropenia following CBT.

Acute Disease↗
PubMed2001

Gamete donation and anonymity: should offspring from donated gametes continue to be denied knowledge of their origins and antecedents?

This paper presents the case for a change from the current practice of anonymity and secrecy in the use of donated gametes in medically assisted conception. It does so by describing history of the practice, various committees of enquiry over the years, their recommendations for consideration of the children created and the need for follow-up of the outcome; presenting the evidence from outcome studies both about child development and family relationships where secrecy is maintained about the child's origin and those where the practice is openly to acknowledge their origins. This is followed by an analysis of the experience and views of these children once they are adults. In discussion of the composite findings recurring themes emerge. From this it is concluded that offspring from donated gametes should not continue to be denied knowledge of their origins and antecedents. In the public debate, four schools of thought are identified. Possible practical scenarios to implement change are discussed. This paper argues that the fundamental issue regarding any of these remains-that priority in decision-making should be the lifelong well-being of the children being created.

Adult↗
PubMed2001

Guidelines for counselling in infertility: outline version.

The Guidelines for Counselling in Infertility describe the purpose, objectives, typical issues and communication skills involved in providing psychosocial care to individuals using fertility services. The Guidelines are presented in six sections. The first section describes how infertility consultations differ from other medical consultations in obstetrics and gynaecology, whereas the second section addresses fundamental issues in counselling, such as what is counselling in infertility, who should counsel and who is likely to need counselling. Section 3 focuses on how to integrate patient-centred care and counselling into routine medical treatment and section 4 highlights some of the special situations which can provoke the need for counselling (e.g. facing the end of treatment, sexual problems). Section 5 deals exclusively with third party reproduction and the psychosocial implications of gamete donation, surrogacy and adoption for heterosexual and gay couples and single women without partners. The final section of the Guidelines is concerned with psychosocial services that can be used to supplement counselling services in fertility clinics: written psychosocial information, telephone counselling, self-help groups and professionally facilitated group work. This paper summarizes the different sections of the Guidelines and describes how to obtain the complete text of the Guidelines for Counselling in Infertility.

Counseling↗
PubMed2000

A new MICA allele with ten alanine residues in the exon 5 microsatellite.

The MICA and MICB genes code for protein products that have structural similarities to major histocompatibility complex (MHC) class I genes. These genes are upregulated by heat stress. They have been shown to interact with a common receptor (NKG2D/DAP10) on gammadelta T cells, CD8+ T cells and natural killer (NK) cells. The MICA gene has an expressed microsatellite, GCT, within the exon 5 which encodes for alanine. So far, four different repetitions of this short tandem have been reported. Also one non-synonymous, one synonymous substitution and a 1-bp insertion within this region have also been described. An association of Behcet's disease with the microsatellite A9 has been reported. Here we report a novel allele with 10 GCT repetitions (A10) which was detected by reference strand mediated conformation analysis and confirmed by DNA sequencing.

Alanine↗
PubMed2000

Three novel MICB alleles.

The two members of the MHC class I chain-related (MIC) gene family, MICA and MICB, have been shown by several investigators to be polymorphic. Most of the research effort so far has focussed on MICA, so less is known about the extent of polymorphism in the MICB gene. Here we report three novel MICB alleles, which had been detected in the course of an SSOP typing study on a large cohort of cell lines. Two of these alleles are formed by a non-synonymous nucleotide variation. Our results confirm previous findings that most of the polymorphisms in the MICB gene, as in MICA, are coding and suggest that the extent of polymorphism in the two genes might be comparable.

Alleles↗
PubMed2000

HLA-B*4413 identified in a UK Caucasoid potential bone marrow donor.

We describe a novel allele belonging to the B*44 allele group. HLA-B*4413 was identified in a Caucasoid potential bone marrow donor from the Anthony Nolan Bone Marrow Trust register. Initial HLA typing of this donor revealed unusual serological reactivity. Further investigation was carried out by reference strand conformation analysis (RSCA) and sequence-based typing (SBT) using DNA extracted from an Epstein-Barr virus (EBV)-transformed B-cell line made from this donor (AMI005AN). In this individual, two B*44 alleles were revealed upon initial investigation: B*4409 and a previously unseen allele which has been named B*4413. B*4413 is identical to B*44031 except for a unique nucleotide substitution resulting in an amino acid difference at residue 61 in the alpha1 helix.

Base Sequence↗
PubMed2000

HLA-B*8202 identified in a Caucasoid potential bone marrow donor.

Sequence analysis of HLA class I alleles has continued to reveal the true extent of polymorphism, particularly for B-locus alleles. This diversity can arise through reshuffling of polymorphic sequences generated by point mutation, resulting in interallelic recombination or intergenic recombination (1). Here we describe a new B-locus allele, B*8202, which is structurally most similar to B*8201, having only one nucleotide difference in exon 3 at nucleotide 557, resulting in an amino acid change of aspartic acid to glycine at residue 162. Glycine is the consensus amino acid for B-locus alleles, which suggests that B*8202 is older than B*8201 in evolutionary terms. B*8201 was found to be a hybrid of B*4501 and B*5602 that may have arisen through recombination events, explaining the serological patterns observed with these allotypes. The importance of high-resolution typing is emphasised here as routine typing suggested the presence of B*8201 and the new variant allele may have been missed had it not been typed further by sequence-based typing.

Alleles↗
PubMed1999

Characterization of the MICA polymorphism by sequence-specific oligonucleotide probing.

A large number of diseases occur in association with specific HLA-B or -C alleles. Recently a new gene, termed major histocompatibility complex class I chain-related gene A (MICA), has been identified in close proximity to HLA-B. The function of this gene is still unknown, but, it is structurally related to HLA class I genes, is polymorphic, and is potentially associated with several diseases. Some DNA-based techniques have previously been described to type for MICA including sequencing and single-strand conformational polymorphism. In this paper we describe the application of sequence-specific oligonucleotide probe based typing for the analysis of the MICA gene. We used a set of 30 oligonucleotide probes to screen for the polymorphisms in exons 2, 3, and 4, which account for the 16 known alleles. We report here the typing results of MICA for 103 B-cell lines that have been well characterized for HLA and describe the linkage disequilibrium between MICA and HLA-B. Unequivocal MICA typing was achieved for 85 of the 103 cells tested, 6 cells gave ambiguous MICA types, and a further 12 cells showed patterns consistent with them expressing at least one new MICA allele.

Alleles↗
PubMed1999

Novel intronic variants of MICB (MHC class I chain-related gene B).

We report an eight-nucleotide duplication in intron 4 of the MICB allele 01021, which was found in samples from different ethnic backgrounds and in association with several HLA-B alleles. We suggest that this new MICB allele is evolutionarily older than HLA-B alleles.

Alleles↗
PubMed1998

Application of RSCA for the typing of HLA-DPB1.

We describe the application of RSCA, for the high resolution typing of alleles encoded at the HLA-DPB1 locus. RSCA differs from other sequence based typing methodologies in that the HLA type is assigned on the basis of differences in DNA conformation between different alleles. A total of 251 samples were typed in a blind study, of these 109 samples had been typed previously by conventional techniques. A comparison of the RSCA data with the historical typing results showed a concordance over 93%. Seven samples initially had discordant results, however, when these samples were typed by direct sequencing, the type assigned by RSCA was found to be correct in all but one case, indicating a concordance over 99%. RSCA has proved to be a simple reliable technique for the typing of the HLA-DPB1 locus, and is not limited by the ambiguous combinations of alleles determined in other conventional techniques.

Alleles↗
PubMed1998

Ethical dilemmas in the use of donor gametes.

Current ethical debate is about the processes of reproductive medicine; the moral status of the embryo. Within a societal acceptance of the expansion of reproductive medicine worldwide, donated gametes are increasingly being used. Medical practice favours anonymity of donors and confidentiality for participants. These apparently legitimate concerns are to protect the adults involved. They do not address the implications for any children thus created. This paper aims to shift the debate and to address specifically the rights and needs of the children following gamete donations. How far do they need to know about their birth origins? How do they fare as future adults with no knowledge of 50% of their genetic family histories? Data is now available about how children themselves view this and, in accord with international declarations about the rights of the child, a radical new approach is urgently needed both in reproductive medicine and legal provisions.

Adult↗
PubMed1995

A study of parenting of IVF and DI children.

This article describes a study which provides data about the long-term issues experienced by parents rearing children from in vitro fertilization and donor insemination programmes. Fifty-four families bringing up a total of 101 children, 74 of whom were the result of assisted conception interventions, were interviewed. The methodology was such as to secure a representative cross-section of participants. The findings presented in this article relevant to medicine and law relate to: (1) The consequences where 50% of the genetic history of a child created by the use of donated gametes is unknown to the parents and the child. (2) The impact of male infertility, as a largely taboo subject, on family relationships, and the consequent deception of the child. (3) The dilemmas of maintaining a secret for a lifetime from much loved children, all relatives and friends.

Child↗