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Biomedical subjects

P Singer

Publications and source records attributed to P Singer.

At least 55 records · Page 3Linked to original sources
PubMed1990

Blood pressure-lowering effect of mackerel diet.

Several dietary studies were designed to evaluate the blood pressure-lowering effect of long-chain n-3 polyunsaturated fatty acids (PUFA) under similar experimental conditions. In the first 3 studies, 15 normotensive volunteers, 14 patients with mild essential hypertension and 15 patients with hyperlipoproteinemias (HLP, phenotypes IIa, IIb, IV and V), respectively, were put on isocaloric diets supplemented either with 2 cans/day of commercially available mackerel fillet in tomato pulp for 2 weeks or with 2 cans/day of herring fillet in tomato pulp for 2 weeks in a crossover regimen. Besides a significant fall of serum cholesterol and triglycerides systolic as well as diastolic blood pressure (BP) from normotensive subjects and systolic blood pressure from mildly hypertensive and hyperlipemic patients was significantly decreased at the end of the mackerel diet providing the twofold higher dose of long-chain n-3 PUFA. Plasma noradrenaline and thromboxane B2 were likewise depressed, the former in normotensive volunteers, the latter in mildly hypertensive patients. In hyperlipemics with an initial systolic BP of 160 mmHg and above the hypotensive effect appeared more pronounced as compared to hyperlipemics with systolic blood pressure below 160 mmHg. In a fourth (long-term) study providing as low as 3 cans/week of mackerel for 8 months systolic and diastolic BP of 12 male patients with mild essential hypertension appeared significantly reduced at the end of the dietary period. This indicates that even a low-dose regimen might effectively lower mildly elevated blood pressure over a long-term period.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1990

Reassessing intensive care for patients with the acquired immunodeficiency syndrome.

The number of patients with the acquired immunodeficiency syndrome (AIDS) admitted to hospitals is increasing dramatically. Treatments such as zidovudine, aerosolized pentamidine, and nutritional support are being administered to subacutely ill patients with increasing effectiveness. The number of patients with AIDS treated in intensive care units, on the other hand, has been decreasing progressively, perhaps as a result of a mortality rate close to 90%. However, because recent data demonstrate (1) a lower mortality rate in patients with AIDS who receive mechanical ventilation and (2) the ability to reverse the wasting syndrome in selected groups, we propose a reassessment of the criteria for intensive care unit admission of patients with AIDS.

AIDS-Related Complex↗
PubMed1989

The quality/quantity-of-life distinction and its moral importance for nurses.

In this paper we reject the "sanctity-of-life" view, which holds that all human lives, irrespective of their quality or kind, are equally valuable and inviolable. We argue that health-care professionals intent on acting in the patients' best interests cannot avoid quality-of-life judgments--for there is a close link between the quality, and kind of life, a patient has and her best interests. This paper reflects on some of these issues.

Decision Making↗
PubMed1989

A mathematical analysis of indirect calorimetry measurements in acutely ill patients.

Beside indirect calorimetry is generally accepted as reliable for evaluating energy expenditure (EE) and oxidation of carbohydrate (dCH) and fat (dF) in critically ill patients. Daily measurement of nitrogen excretion is usually included in the calculation of EE, dCH, and dF but it is difficult to perform in the clinical setting and is not necessary for accurate determination of EE. In this paper new equations, which are suitable for use with critically ill patients, are given for calculating EE, dCH, and dF without N-excretion measurements. With these equations the maximum errors for EE, dCH, and dF were 56, 179, and 306 kcal/d, respectively. The mean errors in 38 measurements of 26 critically ill patients were 27, 86, and 143 kcal/d, respectively. Measurement of EE by these equations is very accurate and suitable for both research and clinical use. Although the calculation of dCH and dF is much less precise, it can still given an indication of fuel utilization.

Acute Disease↗
PubMed1989

Australian commissions and committees on issues in bioethics.

We examine the role of Australian state and federal committees and law reform commissions in bioethics. Most have been concerned with in vitro fertilization and embryo research. We find deficiencies in the standards of reasoning about the underlying ethical issues raised by these techniques. We suggest stronger representation of those with a background in ethics.

Advisory Committees↗
PubMed1988

Doctors' practices and attitudes regarding voluntary euthanasia.

We report the results of a survey of the attitudes and practices of doctors in Victoria with respect to requests for active help in dying from patients who were suffering from a terminal or incurable disease. Questionnaires were sent to 2000 Victorian doctors who had been selected at random, 869 of whom returned completed questionnaires. The survey indicates that a clear majority of those who responded to the questionnaire support active voluntary euthanasia and that many doctors have provided active help in dying. Forty per cent of doctors indicated that they would practise active voluntary euthanasia if it were legal. We compare the results of our survey with a recent telephone survey of British general practitioners.

Adult↗
PubMed1988

Age and the allocation of medical resources.

How are we to decide where our scarce medical resources are most effectively spent? The notion of a quality-adjusted-life-year has been proposed as a way of doing this. Some economists appear to think that this can be done without making ethical assumptions. We examine the application of this notion to the treatment of premature newborns, and especially to comparisons between the value of medical care for newborns, and the value of medical care for older people. We find that some highly questionable ethical assumptions are involved in such comparisons.

Aged↗
PubMed1988

Resolving arguments about the sanctity of life: a response to Long.

Thomas Long has argued that there is an irreconcilable metaphysical difference between the views of those who, like ourselves, believe that on quality-of-life grounds it is sometimes justifiable to end the life of a severely handicapped infant, and those who, like Paul Ramsey, reject this view. Because of this metaphysical difference, Long considers it impossible for our arguments to refute Ramsey's position. We disagree.

Persons with Disabilities↗
PubMed1988

Unilateral onychodystrophy secondary to nail biting.

Whether or not nail biting is a sign of underlying psychiatric disorders is the subject of controversy. We report here a case of nail biting that was unusual in its pattern and severity, and occurred in a patient with previously diagnosed psychiatric disease. The literature regarding psychiatric disease associated with self-inflicted nail disease is reviewed.

Humans↗
PubMed1987

Promoter search by Escherichia coli RNA polymerase on a circular DNA template.

Using the rapid-mixing/photocross-linking technique developed in our laboratory, we have investigated the kinetics of interaction between Escherichia coli RNA polymerase and pAR1319, a recombinant plasmid DNA containing the bacteriophage T7 A2 early promoter. By monitoring the time-dependent density of bound RNA polymerase along the relaxed circular DNA molecule using this technique, we have been able to demonstrate kinetic evidence for linear diffusion of RNA polymerase along DNA in a different system from that previously described (Park, C. S., Hillel, Z., and Wu, C.-W. (1982) J. Biol. Chem. 251, 6950-6956). The nonspecific association rate constant kon was measured to be 7.7 x 10(4) M-1 s-1 at a DNA chain concentration of 22.4 nM. By taking advantage of the fact that rapid mixing displaces bound protein molecules from DNA, but leaves them within the domain of the DNA, the rate of intradomain binding of RNA polymerase to pAR1319 DNA was determined to be 8.2 s-1. Since the plasmid is described by a radius of gyration of 0.22 microns, the intradomain concentration of base pairs could be calculated. Using this concentration (180 microM), the rate constant for intradomain nonspecific association of RNA polymerase to pAR1319 DNA was estimated to be 4.6 x 10(4) M-1 s-1. In addition, a mathematical model has been used to fit the other two important rate constants to the experimental data: koff, which describes the dissociation of RNA polymerase from nonspecific binding sites, and D1, the one-dimensional diffusion coefficient of the enzyme along the DNA molecule. In this model, the circular DNA molecule is described as a ring of interconnected binding sites which together comprise a DNA "domain." RNA polymerase, which enters the domain via three-dimensional diffusion and binds to each site, is allowed to diffuse linearly between adjacent sites and three-dimensionally on and off the DNA molecule. The rate equations for the time-dependent occupancy of each site by RNA polymerase could be written, based on general principles. By solving the resulting family of differential equations, koff and D1 were determined to be 0.3 s-1 and 1.5 x 10(-9) cm2 s-1, respectively.

DNA, Circular↗
PubMed1987

Changes of N-6 and N-3 fatty acids in liver from spontaneously hypertensive (SHR) and normotensive rats after diets supplemented with alpha-linolenic or eicosapentaenoic acids.

In spontaneously hypertensive (SHR) and normotensive rats (WKY), diets supplemented with n-3 fatty acids of different chain length (alpha-linolenic acid, LNA-C 18:3, n-3 with linseed oil and eicosapentaenoic acid, EPA-C 20:5, n-3 with cod liver oil) were fed over a period of 22 weeks. A diet with commercially available pellets served as control. After the LNA-rich diet the augmentation of LNA was most pronounced in liver triglycerides (TG) and free fatty acids (FFA), whereas the increase of EPA was most marked in phosphatidylethanolamine (PE) and phosphatidylcholine (PC) when compared with the controls. Docosahexaenoic acid (DHA) was decreased mainly in neutral lipids. Of the n-6 fatty acids linoleic acid (LA) appeared significantly depressed in TG and FFA, but increased in phospholipids. Arachidonic acid (AA), however, was lower in all lipids. In SHR and WKY fed the EPA-rich diet EPA and DHA were significantly higher as compared to the controls on a pellet diet. On the contrary, LNA was not detectable in all lipid classes. LA and AA were markedly depressed. Docosenoic acids were significantly increased. The p/s-ratio did not reflect the changes in the 20:5/20:4- and n-3/n-6-ratios. The data indicate a differential effect of dietary n-3 fatty acids of different chain length on the supply of other n-3 fatty acids. Moreover, after an LNA-rich diet divergent alterations of LA in neutral lipids and phospholipids occurred. The results are dissimilar to those obtained in adipose tissue. Blood pressure was not influenced by the diets in either SHR or WKY.

Animals↗