Recessive mutations in the cancer gene Ataxia Telangiectasia Mutated (ATM), at a locus previously associated with metformin response, cause dysglycaemia and insulin resistance

AIM

To investigate glucose and insulin metabolism in participants with ataxia telangiectasia in the absence of a diagnosis of diabetes.

METHODS

A standard oral glucose tolerance test was performed in participants with ataxia telangiectasia (n = 10) and in a control cohort (n = 10). Serial glucose and insulin measurements were taken to permit cohort comparisons of glucose-insulin homeostasis and indices of insulin secretion and sensitivity.

RESULTS

During the oral glucose tolerance test, the 2-h glucose (6.75 vs 4.93 mmol/l; P = 0.029), insulin concentrations (285.6 vs 148.5 pmol/l; P = 0.043), incremental area under the curve for glucose (314 vs 161 mmol/l/min; P = 0.036) and incremental area under the curve for insulin (37,720 vs 18,080 pmol/l/min; P = 0.03) were higher in participants with ataxia telangiectasia than in the controls. There were no significant differences between groups in fasting glucose, insulin concentrations or insulinogenic index measurement (0.94 vs 0.95; P = 0.95). The Matsuda index, reflecting whole-body insulin sensitivity, was lower in participants with ataxia telangiectasia (5.96 vs 11.03; P = 0.019) than in control subjects.

CONCLUSIONS

Mutations in Ataxia Telangiectasia Mutated (ATM) that cause ataxia telangiectasia are associated with elevated glycaemia and low insulin sensitivity in participants without diabetes. This indicates a role of ATM in glucose and insulin metabolic pathways.

Weaning from prolonged invasive ventilation in motor neuron disease: analysis of outcomes and survival

INTRODUCTION

Non-invasive ventilation (NIV) improves prognosis in patients with motor neuron disease (MND) in the absence of major bulbar involvement. However, some experience a rapid and unexpected decline in respiratory function and may undergo emergency tracheal intubation. Weaning from invasive ventilation can be difficult, and reported independence from invasive ventilation is uncommon with poor prognosis. The outcomes of patients with MND referred to a specialist weaning service following emergency tracheal intubation were examined and compared with MND patients electively initiating NIV.

METHODS

A case note review was performed on all patients with MND invasively ventilated and referred to a specialist weaning service between 1992 and 2007. Outcomes were compared with those electively commenced on NIV during the same period.

RESULTS

Thirty patients were referred for weaning from invasive ventilation which was started in 17 before MND was diagnosed. Fourteen patients (47%) were weaned from invasive ventilation but still required NIV, 13 failed to wean, and three died. Seventeen were discharged home from hospital. The median survival from tracheal intubation was 13.7 months (95% CI 0 to 30.8) for those previously diagnosed and 7.2 months (95% CI 5.1 to 9.4) for those not previously known to have MND. Comparison with patients initiated electively on NIV demonstrated similar survival estimates to that from emergency intubation (median 9.4 (95% CI 6.9 to 12.0) vs 7.8 (95% CI 2.6 to 12.9) months respectively).

CONCLUSION

The prognosis in MND following acute respiratory failure and intubation is not always complete ventilator dependence if patients are offered a comprehensive weaning programme.

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.

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.

Professional ethics and labor disputes: medicine and nursing in the United Kingdom

The term “industrial action” includes any noncooperation with management, such as strict “working to rule,” refusal of certain duties, going slow, and ultimately withdrawal of labor. The latter form of action, striking, has posed particular problems for professional ethics, especially in those professions that provide healthcare, because of the potential impact on patients' well-being. Examination of the issues, however, displays a difference in response between the healthcare professions, in particular between doctors and nurses. In considering the ethics of industrial (especially strike) action there are various aspects of professional ethics to consider: (1) whether there is a tension between industrial action and the very notion of professional ethics; (2) what specific issues arise in the case of healthcare professions; (3) what, if anything, can explain and/or justify different responses from the medical and nursing professions?

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.

Nurse-initiated thrombolysis in coronary care

National service frameworks emphasise the importance of people who are experiencing a myocardial infarction receiving thrombolysis as quickly as possible. Nurse-initiated thrombolysis is one way to safely achieve the standards.

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?

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?

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.

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.

Can genetic counseling avoid the charge of eugenics?

The claim that x is a form of eugenics is frequently used as if it were a knockdown argument against x. Genetic counseling has tried to distance itself from eugenics by presenting itself as facilitating choice. Its success in this attempt has been challenged. The argument however is not a knockdown one and there is scope for some mediation between autonomy and public health goals in genetics.

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.

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.

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.

When drug treatment in the elderly is not cost effective. An ethical dilemma in an environment of healthcare rationing

In light of moves towards the view that rationing of healthcare resources is inevitable, the question arises as to whether age is a relevant consideration. To hold age as relevant in this context attracts the charge of agism; however, age may be related to some other characteristic(s) that are pertinent. In the context of drug treatment of the elderly, there is evidence to suggest that there are important differences between older and younger patients in terms of adverse responses to drugs because of factors such as physiological changes and multiple health problems, which occur with aging. On the other hand, some studies show beneficial effects of drug therapy. There is a need for more empirical data on cost effectiveness. Ethics arguably have to take into account factors other than cost effectiveness, such as equity. A central question is whether what is required is a set of criteria in addition to cost effectiveness, or an interpretation of cost effectiveness sensitive to broader considerations, such as quality of life (QOL). In relation to the latter, the issue of age-specific measurements of QOL remains problematic.

How can hospitals ration drugs? Fairness is at issue

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The ethics of screening: is 'screeningitis' an incurable disease?

Screening programmes are becoming increasingly popular since prevention is considered 'better than cure'. While earlier diagnosis may result in more effective treatment for some, there will be consequent harm for others due to anxiety, stigma, side-effects etc. A screening test cannot guarantee the detection of all 'abnormal' cases, therefore there will be false reassurance for some. A proper consideration of the potential benefit and harm arising from screening may lead to the conclusion that the programme should not be offered. A modified utilitarian approach may be used for allocation of scarce resources in health care. Ethics has an important role in this evaluation.

Compensation for harm: the implications for medical research

The rising incidence of medical litigation in the 1980's led to a relatively minor modification in January 1990 of the United Kingdom's negligence-based system of medical compensation, as a result of which employing Health Authorities now accept full vicarious liability for the negligent (but not other) actions of employed clinicians (Crown indemnity). During the same period, by contrast, bodies such as the Royal College of Physicians have strongly influenced locally established Research Ethics Committees towards favouring no-fault compensation for harm resulting from medical research. The discordance between these two approaches to compensation has caused anxiety during the last year. There has been particular concern about the possible discouragement of non-commercially sponsored research. Hitherto however, no data has been available to inform this discussion. This paper reports the findings of a questionnaire survey of all research ethics committees in the United Kingdom (64% response rate), which indicates that 61% of committees require no-fault compensation for at least some projects and that 33% of these committees have rejected projects solely or mainly due to the lack of such provision. Rejection is significantly more common in Health Districts which contain teaching hospitals. Our critical analysis of the arguments advanced in favour of no-fault provision for research subjects suggests that they do not place adequate emphasis upon respect for the autonomy of individuals. We consider that it is in general more consistent with such respect fully to inform research subjects of the available compensation arrangements, rather than for ethics committees to make no-fault compensation a general requirement before ethical approval is given.

Ectopic expression from the Deformed gene triggers a dominant defect in Drosophila adult head development

Drosophila adults carrying a dominant allele of the Deformed locus (DfdD) have a mutant phenotype in which lower eye and orbital structures of the adult head are eliminated. The molecular defect responsible for this dominant mutation is a large, transposon-flanked, fragment of DNA inserted downstream of the Deformed (Dfd) transcription unit. The downstream transposon-flanked insert causes the inappropriate activation of Dfd gene expression in a subset of the cells of the eye imaginal disc, resulting in their abnormal development, and in the loss of lower eye structures from the adult head. A chromosome selected for its reversion of the dominant phenotype is missing a portion of the transposon-flanked insert and reverts to a normal expression pattern of Dfd in the eye-antennal disc. Additional evidence that the dominant head phenotype is caused by ectopic expression of Dfd in the eye disc derives from experiments showing that a DfdD-like phenotype can be induced by ectopic expression of a Dfd gene under heat shock promoter control.

Expression and embryonic function of empty spiracles: a Drosophila homeo box gene with two patterning functions on the anterior-posterior axis of the embryo

Using the even-skipped homeo box as a probe to identify diverged homeo box genes in the Drosophila genome, we isolated the empty spiracles (ems) gene. Structural and functional comparisons between ems and other embryonic patterning genes of Drosophila suggest that ems acts, in part, as a homeotic selector gene, specifying the identity of some of the most anterior head segments. Mutant embryos lacking ems protein have severe patterning defects in the anterior head and are missing tracheal structures, including the filzkörper, which are normally developed by the eighth abdominal segment. ems has two different spatial patterns of expression during embryogenesis. The early, head-specific pattern consists of a single anterior stripe at the syncytial and cellular blastoderm stages. The later, metameric pattern consists of bilateral patches of ems expression in neural and ectodermal cells of every head and body segment. Variations of the ems expression pattern in bicoid mutants suggests that the morphogen protein produced by bicoid has a concentration-dependent regulatory role in the establishment of head-specific ems expression. In contrast, the metameric ems pattern is initiated independently of bicoid protein, and ems becomes expressed at high levels in the primordia of the duplicated fïlzkörper that develop in the anterior half of bicoid mutant embryos.

A bill of wrongs: why the students' Bill of Rights gets it wrong

The Nursing Students' Bill of Rights shows how little understanding there is among its authors of the concept of rights. It also demonstrates serious problems about the expectations student nurses face.

A novel, tissue-specific, Drosophila homeobox gene

The homeobox gene family of Drosophila appears to control a variety of position-specific patterning decisions during embryonic and imaginal development. Most of these patterning decisions determine groups of cells on the anterior-posterior axis of the Drosophila germ band. We have isolated a novel homeobox gene from Drosophila, designated H2.0. H2.0 has the most diverged homeobox so far characterized in metazoa, and, in contrast to all previously isolated homeobox genes, H2.0 exhibits a tissue-specific pattern of expression. The cells that accumulate transcripts for this novel gene correspond to the visceral musculature and its anlagen.

Temporal and spatial distribution of transcripts from the Deformed gene of Drosophila

The Deformed gene of Drosophila is necessary for the proper development of epidermal pattern elements arising from the maxillary and mandibular segments of the head. We find one major transcript (2.8 kb) homologous to Deformed (Dfd) probes which is expressed continuously from 3 h of embryogenesis into adulthood. Localized transcript accumulation is first detected just prior to the formation of the cellular blastoderm in a single circumferential band at about 65-75% egg length. The zone of Dfd expression is approximately two segment primordia in width. At later stages of embryogenesis, Dfd transcripts accumulate in the posterior ectoderm of the mandibular segment, and in the ventro-lateral ectoderm of the maxillary segment. Transcripts are also detected in the mesoderm and neuromeres of the mandibular and maxillary segments. The distribution of Dfd transcripts supports the hypothesis that Dfd functions as a homeotic selector gene in the determination of posterior head segments.

Developmental and molecular analysis of Deformed ; a homeotic gene controlling Drosophila head development

The characteristic morphology of many elements of the Drosophila body plan is crucially dependent upon the proper spatial expression of homeotic selector genes. The Deformed locus, which we isolated by virtue of its homology to the homeo box, is a candidate for a homeotic selector in the head region of the developing embryo. Here we show that null mutants of Deformed result in a loss of pattern elements derived from the maxillary and mandibular segments, and a duplication of a cuticular element of the larval head skeleton. Molecular analysis of the locus shows that Dfd transcripts are encoded in five exons distributed over 11 kb. The major transcript of 2.8 kb contains a 1758-bp open reading frame that would translate to yield a 63.5-kd protein containing a homeo domain and conspicuous regions of monotonic amino acid sequences. The Dfd protein exhibits extensive homology to a protein encoded by a Xenopus homeo box gene, Xhox 1A, suggesting that the Xenopus gene is the frog homologue of Dfd.

Pharmacokinetics of cis-diammine-1,1-cyclobutane dicarboxylate platinum(II) in patients with normal and impaired renal function

cis-Diammine-1,1-cyclobutane dicarboxylate platinum(II) (CBDCA, JM8) is a nonnephrotoxic analogue of cisplatin currently undergoing clinical evaluation. Pharmacokinetic studies have been performed in patients receiving CBDCA (20 to 520 mg/sq m) as a 1-hr infusion without hydration or diuresis. Following the end of the infusion, plasma levels of total platinum and ultrafilterable (Mr less than 50,000) platinum (free platinum) decayed biphasically with first-order kinetics (total platinum t alpha 1/2 = 98 min; t beta 1/2 range, 399 to greater than 1440 min; free platinum t alpha 1/2 = 87 min; t beta 1/2 = 354 min). During the first four hr, binding of platinum to plasma protein was limited (24%), with most of the free platinum in the form of unchanged CBDCA (94%). However, by 24 hr, the majority of platinum was protein bound (87%). The major route of elimination was renal, 65% of the platinum administered being excreted in the urine within 24 hr, with 32% of the dose excreted as unchanged CBDCA. No evidence was found from studies on the renal clearance of free platinum to indicate renal tubular secretion (mean free platinum renal clearance, 69 ml/min). However, the plasma clearance of free platinum did correlate positively with glomerular filtration rates (p = 0.005). None of the pharmacokinetic parameters determined were dose dependent. In vitro studies with plasma and urine demonstrated that, in contrast to cisplatin, CBDCA is a stable complex [t 1/2 - 37 degrees; plasma, 30 hr, and urine (range), 20 to 460 hr]. The differences in the pharmacokinetics of cisplatin and CBDCA may explain why the latter complex is not nephrotoxic.