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Biomedical subjects

R Chadwick

Publications and source records attributed to R Chadwick.

At least 37 records · Page 2Linked to original sources
PubMed1995

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.

Aged↗
PubMed1994

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.

Attitude to Health↗
PubMed1992

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.

Compensation and Redress↗
PubMed1990

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.

Animals↗
PubMed1989

Philosophical analysis and its value to the nurse teacher.

Philosophy is often regarded as a subject which is only of interest to those engaged in academic pursuits. This paper suggests that it can be of practical value to nurse teachers. Indeed never more so than today, with the current emphasis on change and decision making, be it in relation to curriculum development or the future of professional education. Change is occurring at such speed, that we have little time to ponder and, therefore, cannot afford 'faulty logic'. The article commences with a description of the processes involved in philosophical analysis, including linguistic and conceptual analysis, asking different types of questions and determining the validity of arguments. It goes on to consider why nurse teachers should adopt this approach and finally the necessity of its inclusion in curricula for basic nurse education.

Concept Formation↗
PubMed1989

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.

Amino Acid Sequence↗
PubMed1988

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.

Amino Acid Sequence↗
PubMed1984

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.

Antineoplastic Agents↗
PubMed1982

An assessment of the Ortho ELT-8.

The Ortho ELT-8 is an automated blood counter which appears to be safe, precise and free from carry-over. Red and white cell results generally agree with those on the Coulter Counter, Model S, though discrepancies were noted with the WBC and PCV. Reference methods showed the Model S WBC results tended to be inaccurate on the discrepant samples though neither instrument was predominantly responsible for the PCV discrepancies. The ELT-8 platelet count tended to be higher than with the Thrombocounter/Thrombofuge system. When packed cells were diluted in autologous plasma serious variations in the red cell indices (MCV, MCH & MCHC) were first found due to incorrect voltage-frequency converter setting. Even after this setting had been corrected some variations in the MCH and MCHC were still apparent. In the UK National External Quality Assessment Scheme the ELT-8 results on animal bloods did not agree with those produced by Model S users; this discrepancy probably being due to differences between the light-scattering and aperture-impedance technology.

Blood Cell Count↗
PubMedDate not supplied

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.

Clinical Protocols↗