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Biomedical subjects

P Singer

Publications and source records attributed to P Singer.

At least 127 records · Page 7Linked to original sources
PubMed1987

Attitudes of Australian neonatal paediatricians to the treatment of extremely preterm infants.

A questionnaire survey was carried out to identify areas of consensus or disagreement in the attitudes and practices of Australian neonatal paediatricians with regard to the treatment of extremely preterm infants. Considerable variation was found in the estimated chances of survival and disability among respondents. The majority of neonatal paediatricians advocated prompt resuscitation and initiation of neonatal intensive care at birth, although all believed life-support treatment should be withdrawn in those instances where medical complications develop resulting in near certainty of death or life with total incapacity. The predominant view was for parents to be involved in the decision-making process for withdrawal of life-support and for the neonatal intensive care policy to be made known to the parents. Information from this survey which raised concerns included the variability in the estimate of the potential for survival, the lack of relevance of the law to everyday practices in the neonatal intensive care units, the small minority of respondents who felt that life-and-death decisions should be made by medical staff alone, and the reluctance of some neonatal paediatricians to inform parents about the policies of their unit.

Adult↗
PubMed1986

Glucose and leucine uptake in the hypoglossal nucleus after hypoglossal nerve transection with and without prevented regeneration in the Sprague-Dawley rat.

We studied [14C]2-deoxyglucose and [14C]leucine uptake in the rat hypoglossal nucleus after hypoglossal nerve transection and when regeneration was prevented by placing a nylon ligature around the nerve proximal to the cut. Glucose and leucine uptake increased after nerve transection in both the animals with nerve transection alone and with the ligature. Both the glucose and leucine uptake increased more in animals with the ligature. The glucose and leucine uptakes returned to normal at 30 and 45 days, respectively, after transection alone and at 60 days in animals in whom regeneration was prevented with a ligature. This suggests that there is a more powerful stimulus to regeneration when regeneration is prevented but that some mechanism turns the process off after a fixed time.

Animals↗
PubMed1986

[Changes in blood pressure and serum lipids with fish diets in patients with mild essential hypertension].

14 male patients with moderate essential hypertension were treated in the cross-comparison with a mackerel and herring diet, respectively, for two weeks. The mackerel diet contained double as much eicosapentaenic (EPA) and docosahexaenic acid (DHA) as the herring diet which served as control. In the serum triglycerides particularly DHS, in the cholesterol esters above all EPA were enriched. In the phospholipids the increase of the two fatty acids was approximately the same. At the end of the mackerel period the serum triglycerides, the total and LDL-cholesterol, the activity of the lecithin-cholesterol-acyl-transferase (CALT) and the serum sodium were significantly decreased. On the other hand, the HDL-cholesterol and the uric acid in the serum significantly increased. Under influence of the herring diet the parameters mentioned appeared only slightly changed. After the mackerel diet also a significantly lower systolic blood pressure was found. The systolic and diastolic blood pressure during a standardized psychophysiological stress test was more diminished at the end of the mackerel period than after the herring diet. The plasma renin activity (PRA) was increased after the mackerel diet. Its increase under the stress test could no more be proved at the end of the mackerel diet. In similar way the stress-conditioned increase of thromboxane B2 could no more be observe both after mackerel and after herring diet. When the results should confirm themselves in long-term studies, a mackerel diet in practicable dosage can be recommended as non-medicamentous treatment of moderate hypertension.

Blood Pressure↗
PubMed1986

Comparative study of the blood pressure effects of four different vegetable fats on young, spontaneously hypertensive rats.

Following the suckling period, four groups of male four-week-old spontaneously hypertensive rats (SHR) were fed semisynthetic diets with 14% (by weight) of either sunflower seed oil [46% 18:2(n-6); linoleic acid (LA)-rich], linseed oil [62.5% 18:3(n-3) + 12.9% 18:2(n-6); alpha-linolenic acid (LNA)-rich], evening primrose oil [9.2% 18:3(n-6) + 71% 18:2(n-6); gamma-linolenic acid (LNA)-rich] or hydrogenated palm kernel fat [1.5% 18:2(n-6); polyunsaturated fatty acid (PUFA)-deficient], respectively, up to an age of 18 wk. All diets enriched with PUFA provoked an attenuation of hypertension development. The effect was lowest in the LA-rich group and highest in the gamma-LNA-rich group. Differences in fatty acid composition of renal phospholipids between groups reflect the fatty acids present in the respective dietary fats. Renomedullary production of PGF2 alpha was significantly reduced in alpha-LNA-rich and slightly diminished in gamma-LNA-rich fed rats. Aortic formation of 6-keto-PGF1 alpha and TXB2 was increased in animals fed the gamma-LNA-rich diet. Thus, the attenuation of hypertension development cannot be explained only by changes in prostanoid formation. Other mechanisms possibly involved should be pursued.

Animals↗
PubMed1986

Long-term effect of mackerel diet on blood pressure, serum lipids and thromboxane formation in patients with mild essential hypertension.

Twelve male patients with mild essential hypertension were put on a diet supplemented with 2 cans of mackerel/day (= 2.2 g daily of eicosapentaenoic acid, EPA, C20:5 n-3 and 2.8 g daily of docosahexaenoic acid, DHA, C22:6 n-3) for 2 weeks within an isocaloric regimen and then with 3 cans/week (= 3.3 g/week, equivalent to 0.47 g daily of EPA and 4.2 g/week, equivalent to 0.69 g daily of DHA) for 8 months with a subsequent period of 2 months on normal diet. Eleven male hypertensives matched for age, body weight index, blood pressure and serum lipids with no change in their nutritional habits served as controls. After the first dietary period (2 weeks) a significant decrease of serum triglycerides (TG), total and LDL-cholesterol, blood pressure and thromboxane B2 (TxB2) was found, whereas HDL cholesterol and potassium in erythrocytes were significantly increased. During the second dietary period (8 months) providing the lower dose of EPA, serum lipids and the other biochemical parameters returned to the initial values. Blood pressure, however, remained significantly lower and rose to the basal levels only after the third period (2 months) on normal diet. In the control group no alterations could be seen. The data suggest a dose-related differential effect of dietary EPA on serum lipids, lipoproteins, TxB2 and blood pressure in subjects with mild hypertension.

Adult↗
PubMed1986

Serum triglycerides and HDL cholesterol from SHR after evening primrose oil and other polyunsaturated fats.

Spontaneously hypertensive rats (SHR) were fed diets enriched with evening primrose (EPO), sunflower (SO) and linseed oils (LO) as well as palm kernel fat (PKF), the latter being deficient in polyunsarated fatty acids (PUFA). In SHR fed EPO serum triglycerides were lowest and HDL1 cholesterol was highest as compared to the other groups of animals. Total cholesterol was not different. The data suggest that - as with blood pressure - serum lipids and lipoproteins might be influenced most effectively by EPO in comparison to other polyunsaturated fats.

Administration, Oral↗
PubMed1986

Different changes of n-6 and n-3 fatty acids in adipose tissue from spontaneously hypertensive (SHR) and normotensive rats after diets supplemented with linolenic or eicosapentaenoic acids.

In spontaneously hypertensive (SHR) and normotensive rats of the Wistar-Kyoto (WKY) and Wistar-Schönwalde (WSCHOE) strain, 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. After the LNA-rich diet, among the long-chain n-3 fatty acids EPA in epididymal adipose tissue remained unchanged, whereas docosapentaenoic (DPA) and docosahexaenoic acids (DHA) fell. The n-6 fatty acids linoleic (LA) and arachidonic acid (AA) both appeared decreased. After the EPA-rich diet, all n-3 fatty acids, i.e. not only EPA, DPA and DHA, but also LNA were augmented when compared with controls fed commercially available pellets. Among the n-6 fatty acids LA was extremely depressed, whereas AA appeared increased. The p/s-ratio was elevated after the LNA-rich diet, but decreased after the EPA-rich diet. 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, of LA and AA as well as on the p/s-ratio in adipose tissue of rats. Blood pressure was not influenced by either diet in either SHR or in both normotensive strains of rats.

Adipose Tissue↗
PubMed1986

Slow desaturation and elongation of linoleic and alpha-linolenic acids as a rationale of eicosapentaenoic acid-rich diet to lower blood pressure and serum lipids in normal, hypertensive and hyperlipemic subjects.

In normal, hypertensive and hyperlipemic subjects, diets supplemented with linoleic acid (LA) or alpha-linolenic acid (LNA) resulted in an increase of the corresponding fatty acids in serum lipids. However, their C20-derivatives, the prostaglandin precursors arachidonic acid (AA) and eicosapentaenoic acid (EPA), respectively, were not or only slightly augmented. On the other hand, an EPA-rich diet produced a marked increase of this fatty acid, especially in cholesterol esters. After this diet the decreases of blood pressure and serum lipids were more pronounced when compared with LA- and LNA-rich diets containing a 20-fold higher dose of the polyunsaturated fatty acids. The slow formation of AA and EPA from LA and LNA seems to be a characteristic finding in humans, being different from preferred laboratory animals, for instance, rats. This observation was independent of the presence of risk factors, like arterial hypertension or hyperlipoproteinemia (HLP).

Adult↗
PubMed1985

Blood pressure lowering effect of eicosapentaenoic acid-rich diet in normotensive, hypertensive and hyperlipemic subjects.

A mackerel diet or a herring diet in which two cans of fish fillet were consumed daily over 2 weeks within a prescribed regimen, in a crossover design, were given to 15 normotensive volunteers, 14 patients with mild essential hypertension and eight patients with type IV and V hyperlipoproteinemia (HLP). In normotensives a markedly lower systolic and diastolic blood pressure at the end of the period on the mackerel diet could be observed, whereas in hypertensive and hyperlipemic subjects only systolic blood pressure was significantly decreased. After the herring diet, which served as control, changes in blood pressure were of a minor degree.

Adult↗