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Biomedical subjects

R Chadwick

Publications and source records attributed to R Chadwick.

At least 19 recordsLinked to original sources
PubMed2001

Mutations in the RNA component of RNase MRP cause a pleiotropic human disease, cartilage-hair hypoplasia.

The recessively inherited developmental disorder, cartilage-hair hypoplasia (CHH) is highly pleiotropic with manifestations including short stature, defective cellular immunity, and predisposition to several cancers. The endoribonuclease RNase MRP consists of an RNA molecule bound to several proteins. It has at least two functions, namely, cleavage of RNA in mitochondrial DNA synthesis and nucleolar cleaving of pre-rRNA. We describe numerous mutations in the untranslated RMRP gene that cosegregate with the CHH phenotype. Insertion mutations immediately upstream of the coding sequence silence transcription while mutations in the transcribed region do not. The association of protein subunits with RNA appears unaltered. We conclude that mutations in RMRP cause CHH by disrupting a function of RNase MRP RNA that affects multiple organ systems.

Alleles↗
PubMed2001

Solidarity and equity: new ethical frameworks for genetic databases.

Genetic database initiatives have given rise to considerable debate about their potential harms and benefits. The question arises as to whether existing ethical frameworks are sufficient to mediate between the competing interests at stake. One approach is to strengthen mechanisms for obtaining informed consent and for protecting confidentiality. However, there is increasing interest in other ethical frameworks, involving solidarity--participation in research for the common good--and the sharing of the benefits of research.

Confidentiality↗
PubMed2001

Euroscreen 2: towards community policy on insurance, commercialization and public awareness.

The project Euroscreen 2 has examined genetic screening and testing with particular reference to implications for insurance, commercialization through marketing of genetic tests direct to the public, and issues surrounding raising public awareness of these and other developments in genetics, including the practical experiment of a Gene Shop. This paper provides a snapshot of the three year project. The study group's work included monitoring developments in different European countries and exploring possibilities for regulation in insurance and commercialization together with public attitudes to regulation. The success or failure of different strategies is not independent of public awareness. Exploration of policy, however, also requires examination of fundamental concepts such as solidarity and geneticization.

Attitude to Health↗
PubMed2000

Editorial.

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Bioethical Issues↗
PubMed2000

Ethical issues in psychiatric care: geneticisation and community care.

This paper will examine two different though related themes in current debates about ethical issues in psychiatric care. There is, first, the general question of who should be the main focus of the debate: the individual, the family, the local community, or the wider society? Secondly, the current controversies about the genetic basis of mental disorders will be explored with reference to their implications for both images and understanding of mental disorders and for psychiatric care. Would the understanding of the genetic causes of mental disorder lead to better treatments and better acceptance or to the potential for increased discrimination and stigmatisation?

Community Health Services↗
PubMed2000

From the editors.

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Bioethics↗
PubMed1999

Beware! Preimplantation genetic diagnosis may solve some old problems but it also raises new ones.

Preimplantation genetic diagnosis (PIGD) goes some way to meeting the clinical, psychological and ethical problems of antenatal testing. We should guard, however, against the assumption that PIGD is the answer to all our problems. It also presents some new problems and leaves some old problems untouched. This paper will provide an overview of how PIGD meets some of the old problems but will concentrate on two new challenges for ethics (and, indeed, law). First we look at whether we should always suppose that it is wrong for a clinician to implant a genetically abnormal zygote. The second concern is particularly important in the UK. The Human Fertilisation and Embryology Act (1990) gives clinicians a statutory obligation to consider the interests of the future children they help to create using in vitro fertilisation (IVF) techniques. Does this mean that because PIGD is based on IVF techniques the balance of power for determining the best interests of the future child shifts from the mother to the clinician?

Adult↗
PubMed1998

Characterization of 12 microsatellite loci of the human MHC in a panel of reference cell lines.

The human genome contains a large number of interspersed microsatellite repeats which exhibit a high degree of polymorphism and are inherited in a Mendelian fashion, making them extremely useful genetic markers. Several microsatellites have been described in the HLA region, but allele nomenclature, a set of broadly distributed controls, and typing methods have not been standardized, which has resulted in discrepant microsatellite data between laboratories. In this report we present a detailed protocol for genotyping microsatellites using a semi-automated fluorescence-based method. Twelve microsatellites within or near the major histocompatibility complex (MHC) were typed in the 10th International Histocompatibility Workshop homozygous typing cell lines (HTCs) and alleles were designated based on size. All loci were sequenced in two HTCs providing some information on the level of complexity of the repeat sequence. A comparison of allele size obtained by genotyping versus that obtained by direct sequencing showed minor discrepancies in some cases, but these were not unexpected given the technical differences in the methodologies. Fluorescence-based typing of microsatellites in the MHC described herein is highly efficient, accurate, and reproducible, and will allow comparison of results between laboratories.

Alleles↗
PubMed1998

Genetic screening.

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Ethics, Medical↗
PubMed1998

Genetic screening and ethics: European perspectives.

Analysis and comparison of genetic screening programs shows that the extent of development of programs varies widely across Europe. Regional variations are due not only to genetic disease patterns but also reflect the novelty of genetic services. In most countries, the focus for genetic screening programs has been pregnant women and newborn children. Newborn children are screened only for disorders which are treatable. Prenatal screening when provided is for conditions for which termination may be offered. The only population screening programs for adults are those for thalassaemia carrier status in Cyprus, Greece and Italy. Social responses to genetic screening range from acceptance to hostility. There is a fundamental tension between individual and community in the debates in various European countries about implementation of screening programs. Opposition to genetic screening is frequently expressed in terms of arguments about "eugenics" with insufficient regard to the meaning of the term and its implications. Only a few countries have introduced explicit legislation on genetic screening. Legislation to address discrimination may provide more safeguards than legislation protecting genetic information itself.

Adult↗
PubMed1997

Inhibitory consequences of memory selection.

When subjects select a prime from a visual display while leaving a distractor prime unselected, response time (RT) or response accuracy to a subsequent probe may be impeded if the distractor prime and probe are identical, or if they are related to one another. This phenomenon, negative priming (NP), has obvious implications for understanding perceptual selection. However, it is not known whether NP results from other kinds of selection processes. The present studies were designed to investigate whether NP occurs when primes are selected from working memory rather than from a visual display. In the two experiments, the subjects memorized two primes, selected one prime for further processing, and classified the contents of a probe display. Significant NP occurred in both Experiments. In Experiment 2, however, NP occurred only under easy-selection conditions; the effect was reversed under difficult-selection conditions. The findings indicate a role for NP in memory processing, but contrast with the results from perceptual selection studies showing greater NP under difficult-selection than under easy-selection conditions. The present finding suggests a complex and perhaps strategy-dependent relationship between memory selection difficulty and NP.

Analysis of Variance↗
PubMed1997

Genetic screening: a comparative analysis of three recent reports.

Three recent reports on genetic screening published in the United Kingdom, Denmark and the Netherlands are discussed. Comparison of the Dutch report with the Danish and the Nuffield reports reveals that the Dutch report focuses on the aim of enlarging the scope for action, emphasising protection of autonomy and self-determination of the screenee more than the other two reports. The three reports have in common that the main concern is with concrete issue such as stigmatisation, discrimination, protection of the private sphere and issues linked with labour and insurance. Some potential long term consequences, however, tend to be neglected or underestimated. These omissions are pointed out.

Advisory Committees↗
PubMed1996

On people's understanding of the diagnostic implications of probabilistic data.

Two lines of prior research into the conditions under which people seek information are examined in light of two statistical definitions of diagnosticity. Five experiments are reported. In two, subjects selected information in order to test a hypothesis. In the remaining three, they selected information in order to convince someone else of the truth of a known hypothesis. A total of 567 university students served as subjects. The two primary conclusions were as follows: (1) When the task is highly structured by the environment, subjects select information diagnostically, and (2) when the task is less structured, so that subjects must seek relevant information not manifest, they select information pseudodiagnostically. Possible relations to other laboratory inference tasks and to clinical judgment are discussed.

Concept Formation↗