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Biomedical subjects

P Singer

Publications and source records attributed to P Singer.

At least 37 records · Page 2Linked to original sources
PubMed1990

N-6 and N-3 PUFA in liver lipids, thromboxane formation and blood pressure from SHR during diets supplemented with evening primrose, sunflowerseed or fish oil.

Spontaneously hypertensive rats (SHR) after weaning (at 4 weeks of age) were fed diets supplemented with either sunflowerseed oil (SO), evening primrose oil (EPO), fish oil (FO) or EPO + FO (50%: 50%, v/v) for 22 weeks. A diet with commercially available pellets served as control. Systolic blood pressure was significantly lower in the dietary groups receiving FO, EPO and FO + EPO, the former being most effective. In liver triglycerides (TG) EPO resulted in a markedly increased percentage of linoleic acid (LA; C 18:2, n-6), alpha-linolenic acid (alpha-LNA; C 18:3, n-6) and especially of arachidonic acid (AA; C 20:4, n-6), whereas the long-chain n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA; C 20:5, n-3) and docosahexaenoic acid (DHA; C 22:6 n-3), were depressed to undetectable and significantly lower levels, respectively. In liver phosphatidylcholine (PC) and phosphatidylethanolamine (PE) only slight changes of LA and AA were observed. Feeding of FO led to a significant rise of EPA and DHA in liver TG, PC and PE at the expense of n-6 PUFA (except LA in PC and PE). With a combination of both EPO and FO a significant increase of EPA and DHA, but on lower levels as compared to FO alone, was associated with a significant rise of LA, but with a slight decline of AA as compared to the control animals. Nevertheless, the levels of AA in the group fed EPO + FO were still higher than in the FO-group. In the SO-group the increase of LA was even higher when compared with the EPO-group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Blood pressure and serum lipids from SHR after diets supplemented with evening primrose, sunflowerseed or fish oil.

Spontaneously hypertensive rats (SHR) at 4 weeks of age were fed a diet supplemented with sunflowerseed oil (SO), evening primrose oil (EPO), fish oil (FO) or EPO + FO for 22 weeks. A diet with commercially available pellets served as control. Systolic blood pressure was significantly lower during and after FO, EPO and EPO + FO, whereas the lower level after SO was not significant when compared with the controls. Serum triglycerides and total cholesterol were lowest after EPO followed FO. The combination of both EPO and FO resulted in unexpected high values of triglycerides and cholesterol. HDL-cholesterol was likewise highest after EPO + FO. The results indicate a quantitatively different depression of blood pressure and serum lipids from SHR by individual polyunsaturated fatty acids (PUFA).

Animals↗
PubMed1990

Respiratory and sleep patterns during nocturnal infusions of branched chain amino acids.

In the awake, normal subject, infusions of branched chain amino acids (BCAA) alter the ventilatory response to CO2. If this effect extends to the sleep state, it could contribute to our understanding of the neurophysiology of the sleep state as well as having clinical utility in ameliorating or preventing apnea syndromes. This study examined the effect of nocturnal BCAA infusion on sleep patterns (as measured by EEG, chest wall motion, Sao2 and end-tidal CO2) in five normal male subjects. Subjects were monitored with a polysomnograph from 21.00 to 7.00. Each subject was studied double-blind in random order on three occasions: a) baseline, no infusion (B); b) control, with normal saline infusion (S); and c) treatment, infusion of BCAA (BCAA). Sleep pattern analysis did not demonstrate any measurable effect of the BCAA infusion. End-tidal CO2 levels during BCAA infusion were lower than during baseline or control nights (mean +/- s.d.; BCAA: 5.8 +/- 0.7 kPa vs. B: 6.9 +/- 0.1 kPa, P less than 0.01 and S: 6.7 +/- 0.4 kPa, P less than 0.05). This study demonstrates that nocturnal BCAA infusions have effects on respiratory control during sleep; further clinical studies are required to determine whether these data have implications for disease states.

Adult↗
PubMed1990

Fish oil amplifies the effect of propranolol in mild essential hypertension.

Forty-seven male patients with mild essential hypertension were randomly allocated to three subgroups. After a run-in period of 4 weeks, the first subgroup (n = 16) received propranolol (80 mg/day) for 36 weeks followed by a placebo period of 4 weeks. The second subgroup (n = 15), after a run-in period of 4 weeks, was given a supplement of encapsulated fish oil (9 g/day) for 36 weeks with a subsequent period of 4 weeks in which fish oil placebo was given. The third subgroup (n = 16), after a run-in period of 4 weeks, was given propranolol (80 mg/day) for 12 weeks, propranolol (80 mg/day) plus fish oil capsules (9 g/day equivalent to 1.8 g/day of eicosapentaenoic acid and 1.1 g/day of docosahexaenoic acid) for 12 weeks, propranolol plus fish oil placebo (same doses for 12 weeks) with a subsequent period of 4 weeks when propranolol placebo was administered. The results indicate a blood pressure-lowering effect of fish oil, which was comparable with that of propranolol. The simultaneous intake of fish oil plus propranolol was more effective than propranolol or fish oil alone. Propranolol treatment resulted in a decrease of plasma norepinephrine, plasma renin activity, and thromboxane B2 formation. After fish oil supplementation, plasma norepinephrine and thromboxane B2 formation were likewise reduced, whereas plasma renin activity appeared increased. The decrease of serum triglycerides, total and low density lipoprotein cholesterol as well as the rise of high density lipoprotein cholesterol are concomitant beneficial effects, which justify the consideration of fish oil alone or in combination with antihypertensive drugs for the treatment of mild hypertension.

Adult↗
PubMed1990

Effects of dietary oleic, linoleic and alpha-linolenic acids on blood pressure, serum lipids, lipoproteins and the formation of eicosanoid precursors in patients with mild essential hypertension.

Forty-four male in-patients with mild essential hypertension were randomly allocated to three groups and put on diets supplemented with 60 ml/day of olive (n = 15), sunflowerseed (n = 15) or linseed oils (n = 14), respectively, for two weeks within a blind study. In the group receiving sunflowerseed oil an increase of linoleic acid in serum lipids could be observed, whereas arachidonic and eicosapentaenoic acids appeared unchanged in serum triglycerides and even significantly lower in cholesterol esters. The subjects ingesting the linseed oil-rich diet showed an increase of alpha-linolenic acid in serum lipids, whereas arachidonic and eicosapentaenoic acids remained unchanged in serum triglycerides. In cholesterol esters, however, arachidonic acid was significantly decreased and eicosapentaenoic acid appeared increased only to a low level of significance. In the group put on the olive oil-rich regimen only a significant fall of linoleic acid was obvious in serum triglycerides. The results might indicate a defective desaturation and elongation of linoleic and alpha-linolenic acids and, consequently, a slow formation of arachidonic and eicosapentaenoic acids in patients with mild essential hypertension, which should be considered in dietary studies. After the sunflowerseed oil-rich diet a significant decrease of total cholesterol, low density lipoprotein (LDL) cholesterol and the LDL/high density lipoprotein (HDL) cholesterol ratio was found. Systolic blood pressure during a psychophysiological stress test and urinary sodium excretion appeared significantly lower after the linoleic acid-rich diet. After the linseed oil-rich diet, in addition to total cholesterol, LDL cholesterol and the LDL/HDL cholesterol ratio, serum triglycerides and lecithin cholesterol acyl transferase (LCAT) activity were significantly depressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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↗