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Biomedical subjects

P Singer

Publications and source records attributed to P Singer.

At least 73 records · Page 4Linked to original sources

Acute beriberi following liver transplantation.

Patients scheduled for orthotopic liver transplantation (OLT) undergo extensive routine preoperative cardiac assessment. We describe a 32-year-old male who underwent uneventful OLT for endstage liver failure on the basis of chronic hepatitis C and alcoholism. Despite a normal preoperative cardiac workup, the patient developed acute pulmonary edema on the second postoperative day. A diagnosis of beriberi was entertained and confirmed by (1) the thiamine diphosphate effect and (2) the dramatic response to intravenous thiamine. Possible precipitating factors are described. Thiamine, which has no significant toxicity, should probably be routinely supplemented in all patients undergoing OLT, especially those with a previous history of alcohol abuse.

Journal Article↗

Home parenteral lipids in AIDS: a three-month study.

Parenteral nutrition is a part of the nutritional support regimen of patients with AIDS-associated wasting syndrome and gastrointestinal dysfunction. The cholesterol (CHOL) level in human immunodeficiency virus (HIV) membrane is very high, and recent lipid formulations with high phospholipid (PL) content have demonstrated the ability to trap CHOL from endogenous sources, modifying the composition of cell membranes. We administered lipid-based home parenteral nutrition for 3 mo to malnourished AIDS patients. The patients were randomly divided into two groups: 23 received the regular 20% fat emulsion formulation, and 27 received a 2% formulation enriched 10-fold with PLs but containing the same amount of triglycerides. All patients gained weight and improved their activity level. Those receiving the high-PL composition showed increased serum CHOL concentrations (from 147 to 241 mg/dL; P < 0.01), but no increase was seen in the number of CD4 cells or improvement in immune function. HIV infectivity was not modified. Patients receiving regular PLs had significantly decreased (P < 0.02) IgA concentrations (from 776 to 300 mg/dL) and improved mitogen response to phytohemagglutinin and to concanavalin A. This formula, too, had no effect on HIV infectivity. We conclude that standard parenteral nutritional influences the nutritional and immune status of malnourished AIDS patients. A PL-enriched parenteral formulation can trap CHOL, but it does not affect the immune profile or HIV infectivity in patients with advanced disease.

Acquired Immunodeficiency Syndrome↗

Neither human nor natural: ethics and feral animals.

There are three major ethical approaches to issues affecting nonhuman animals and the natural environment: an anthropocentric ethic, and ethic of concern for all sentient beings, and a biocentric approach. The ethic of concern for all sentient beings is the most defensible basis for resolving conflicts between the interests of humans and wild animals. There is no ethical basis for discounting the suffering of an animal simply because that being is a member of a different species. On the other hand, it is certainly true that human and nonhuman animals differ in their capacities, and this does make a difference to the ethics of what we may do to them, including rendering them infertile. Since ethics is not a matter of adhering to absolute rules, but rather of doing what will have best consequences, given the constraints under which we act, the ethics of using a specific method of fertility control for feral animals will depend on what other methods are being used, or will be used, if the given method is not available. It will also depend on the consequences of not using any method of controlling the population of the animals.

Animal Welfare↗

Partial and impartial ethical reasoning in health care professionals.

OBJECTIVES: To determine the relationship between ethical reasoning and gender and occupation among a group of male and female nurses and doctors. DESIGN: Partialist and impartialist forms of ethical reasoning were defined and singled out as being central to the difference between what is known as the "care" moral orientation (Gilligan) and the "justice" orientation (Kohlberg). A structured questionnaire based on four hypothetical moral dilemmas involving combinations of (health care) professional, non-professional, life-threatening and non-life-threatening situations, was piloted and then mailed to a randomly selected sample of doctors and nurses. SETTING: 400 doctors from Victoria, and 200 doctors and 400 nurses from New South Wales. RESULTS: 178 doctors and 122 nurses returned completed questionnaires. 115 doctors were male, 61 female; 50 nurses were male and 72 were female. It was hypothesised that there would be an association between feminine subjects and partialist reasoning and masculine subjects and impartialist reasoning. It was also hypothesised that nurses would adopt a partialist approach to reasoning and doctors an impartialist approach. No relationship between any of these variables was observed.

Attitude of Health Personnel↗

The significance of age and duration of effect in social evaluation of health care.

To give priority to the young over the elderly has been labelled 'ageism'. People who express 'ageist' preferences may feel that, all else equal, an individual has greater right to enjoy additional life years the fewer life years he or she has already had. We shall refer to this as egalitarian ageism. They may also emphasise the greater expected duration of health benefits in young people that derives from their greater life expectancy. We may call this utilitarian ageism. Both these forms of ageism were observed in an empirical study of social preferences in Australia. The study lends some support to the assumptions in the QALY approach that duration of benefits and hence old age, should count in prioritising at the budget level in health care.

Age Factors↗

Neutrophil chemotactic activity is increased in nasal secretions of long-distance runners.

For years physicians have observed a high incidence of infections after strenuous exercise. Recent observations suggest an increase of neutrophils in the upper airways following a long-distance race. In order to elucidate mechanisms responsible for the influx of neutrophils in airway mucosa, we tested neutrophil chemotactic activity (NCA) in nasal lavages of amateur runners. Thirty-six amateur runners entered in a marathon race (42.2 km) and 24 healthy sedentary subjects participated in the study. Nasal lavages (NAL) were performed several times before and after the race. The total number of recovered neutrophils was measured and the NCA was determined using a modified Boyden chamber. The number of PMNs in NAL of the runners immediately after the race was increased 2.7-fold (p < 0.01) compared to the values obtained on the same day prior to the race (128 +/- 19 vs. 48 +/- 16, x 10(3)), remained elevated several days after the race and returned to baseline after 1 week. The race resulted also in a 2.5-fold (p < 0.01) increase of NCA immediately after the competition compared to the pre-race values of the same day (78 +/- 5.2 cells/8 High Power Fields, HPF vs. 31 +/- 3.4 cells/8 HPF). The findings suggest that NCA might play an important role in attracting neutrophils to the airways. The nature and origin of NCA in airway secretions is presently not known.

Adult↗

Double jeopardy, the equal value of lives and the veil of ignorance: a rejoinder to Harris.

Harris levels two main criticisms against our original defence of QALYs (Quality Adjusted Life Years). First, he rejects the assumption implicit in the QALY approach that not all lives are of equal value. Second, he rejects our appeal to Rawls's veil of ignorance test in support of the QALY method. In the present article we defend QALYs against Harris's criticisms. We argue that some of the conclusions Harris draws from our view that resources should be allocated on the basis of potential improvements in quality of life and quantity of life are erroneous, and that others lack the moral implications Harris claims for them. On the other hand, we defend our claim that a rational egoist, behind a veil of ignorance, could consistently choose to allocate life-saving resources in accordance with the QALY method, despite Harris's claim that a rational egoist would allocate randomly if there is no better than a 50% chance of being the recipient.

Australia↗

Another peep behind the veil.

Harris argues that if QALYs are used only 50% of the population will be eligible for survival, whereas if random methods of allocation are used 100% will be eligible. We argue that this involves an equivocation in the use of "eligible", and provides no support for the random method. There is no advantage in having a 100% chance of being "eligible" for survival behind a veil of ignorance if you still only have a 50% chance of survival once the veil is lifted. A 100% chance of a 50% chance is still only a 50% chance. We also argue that Harris provides no plausible way of dealing with the criticism that his random method of allocation may result in the squandering of resources.

Australia↗

Caring and justice: a study of two approaches to health care ethics.

This article presents an empirical study of approaches to ethical decision-making among nurses and doctors. It takes as its starting point the distinction between the perspectives of care and of justice in ethical thinking, and the view that nurses' thinking will be aligned with the former and doctors' with the latter. It goes on to argue that the differences in these approaches are best understood in terms of the distinction between partialist and impartialist modes of moral thinking. The study seeks to determine the distribution of these modes of thinking between nurses and doctors, and finds that these are no significant differences between them. A 'two-level' philosophical view of the nature of moral thinking is appealed to in order to explain the study findings.

Adult↗

Mutagenesis and Laue structures of enzyme intermediates: isocitrate dehydrogenase.

Site-directed mutagenesis and Laue diffraction data to 2.5 A resolution were used to solve the structures of two sequential intermediates formed during the catalytic actions of isocitrate dehydrogenase. Both intermediates are distinct from the enzyme-substrate and enzyme-product complexes. Mutation of key catalytic residues changed the rate determining steps so that protein and substrate intermediates within the overall reaction pathway could be visualized.

Binding Sites↗

Who cares about cost? Does economic analysis impose or reflect social values?

In a two-stage survey, a cross-section of Australians were questioned about the importance of costs in setting priorities in health care. Generally, respondents felt that it is unfair to discriminate against patients who happen to have a high cost illness and that costs should therefore not be a major factor in prioritising. The majority maintained this view even when confronted with its implications in terms of the total number of people who could be treated and their own chance of receiving treatment if they fall ill. Their position cannot be discarded as irrational, as it is consistent with a defensible view of utility. However, the results suggest that the concern with allocative efficiency, as usually envisaged by the economists, is not shared by the general public and that the cost-effectiveness approach to assigning priorities in health care may be imposing an excessively simple value system upon resource allocation decision-making.

Attitude to Health↗

Maximizing health benefits vs egalitarianism: an Australian survey of health issues.

Economists have often treated the objective of health services as being the maximization of the QALYs gained, irrespective of how the gains are distributed. In a cross section of Australians such a policy of distributive neutrality received: (a) very little support when health benefits to young people compete with health benefits to the elderly; (b) only moderate support when those who can become a little better compete with those who can become much better; (c) only moderate support when smokers compete with non smokers; (d) some support when young children compete with newborns; and (e) wide spread support when parents of dependent children compete with people without children. Overall, the views of the study population were strongly egalitarian. A policy of health benefit maximization received very limited support when the consequence is a loss of equity and access to services for the elderly and for people with a limited potential for improving their health.

Adult↗