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Biomedical subjects

A J Sinclair

Publications and source records attributed to A J Sinclair.

At least 163 records · Page 9Linked to original sources
PubMed1986

Animal foods in traditional Australian aboriginal diets: polyunsaturated and low in fat.

Australian Aborigines develop high frequencies of diabetes and cardiovascular diseases when they make the transition to an urban lifestyle. The composition of the traditional diet, particularly its lipid components, is a most important aspect of the hunter-gatherer lifestyle that would bear on the risk of these diseases. We have examined the fat content and fatty acid composition of a variety of animal foods eaten traditionally by Aborigines from different regions of Australia. The muscle samples of the wild animals from all over Australia were uniformly low in fat (less than 2.6% wet weight) with a high proportion of polyunsaturated fatty acids (greater than or equal to 20% PUFA). Liver samples had a higher range of fat content (5-10% wet weight) but were also rich in PUFA (33-42%). Depot fat samples varied widely in their PUFA content (5-40%). In terms of their PUFA composition the foods tended to fall into three groups: (i) those rich in both n-3 and n-6 PUFA, which included land-based, coastal and freshwater animals; (ii) those rich in n-3 PUFA, i.e., marine species; (iii) those rich in n-6 PUFA, mainly land-based species. The results of these analyses suggest that even when the traditional Aboriginal diet contained a high proportion of animal foods it would have been low in fat with a high proportion of PUFA and thereby could have protected Aborigines against cardiovascular diseases and related conditions through a combination of factors: low energy density, low saturated fat and relatively high PUFA content.

Animals↗
PubMed1985

The effects of low-fat diets rich in arachidonic acid on the composition of plasma fatty acids and bleeding time in Australian aborigines.

In the present study we measured the bleeding times in fourteen Aborigines (10 diabetic, 4 non-diabetic) before and after 2 weeks on a diet of tropical seafood (rich in both arachidonic acid and the omega 3 PUFA), followed by 3 weeks on a diet in which kangaroo and freshwater fish (linoleic and arachidonic acid-rich) were the major fat sources. Both diets were very low in fat. Bleeding times increased in all subjects after the 2 weeks of tropical seafood and continued to rise on the mixed diet. The increase over 5 weeks from 4.1 +/- 0.4 to 5.9 +/- 0.4 min was highly significant (p less than 0.01). Due to the extreme isolation of the study location it was only possible to measure the plasma fatty acid composition at the beginning and end of the study. The concentration of arachidonic acid in the plasma lipids doubled whereas that of linoleic acid was almost halved, despite the fact that the diet in the second part of the study contained considerably more linoleic than arachidonic acid. That there appeared to be preferential incorporation of arachidonic acid into the plasma lipids is further supported by the observation that the rise in arachidonic acid in the cholesterol ester and phospholipid fractions was almost exactly counter-balanced by the fall in linoleic acid. In conclusion, the present study demonstrated a rise in bleeding time associated with an increased concentration of arachidonic acid and decreased concentration of linoleic acid in plasma lipids, and suggests that the mechanism by which diet modulates haemostatic function may be more complex than currently assumed.

Animals↗
PubMed1984

Pancreatic degeneration in broilers with runting and stunting syndrome.

A number of plasma biochemical parameters were examined in five outbreaks of runting in broiler chickens. In four of the five outbreaks, runts showed consistent elevations in plasma amylase activity and reductions in glutathione peroxidase activity. In two of the five outbreaks the plasma vitamin E concentration was reduced, as was the activity of plasma alkaline phosphatase. A highly significant number of runted chickens were found to have pancreatic degeneration, elevated plasma amylase activity and reduced plasma glutathione peroxidase activity, compared with non-runted chickens. The implications of these changes are discussed in relation to the aetiology of runting and stunting syndrome and, in particular, the possible involvement of selenium.

Alkaline Phosphatase↗
PubMed1984

Differentiation of Brucella ovis from Brucella abortus by gas-liquid chromatographic analysis of cellular fatty acids.

The cellular fatty acid composition of Brucella ovis and Brucella abortus strains was determined by gas-liquid chromatography. Both species were characterized by the presence of fatty acids 16:0, 17:0, 17:0 cyclopropane, 18:0, 18:1, and 19:0 cyclopropane; B. ovis also contained some 15:0. There were differences in the relative proportions of the fatty acids present, and it was possible to differentiate B. ovis from B. abortus on the basis of the absence of 15:0, lower concentrations of 17:0 and 18:1, and higher concentrations of 19:0 cyclopropane in B. abortus. The data indicate that analysis of cellular fatty acid composition by gas-liquid chromatography can be used for the identification of B. ovis and its differentiation from B. abortus.

Brucella↗
PubMed1983

Elevated levels of arachidonic acid in fish from northern Australian coastal waters.

The fatty acid composition of 10 species of fish caught off the northwest coast of Australia (latitude 17 degrees S) was examined. All species contained high levels of omega 6 fatty acids (9.6-23.1% of total fatty acids) with arachidonic acid being the major omega 6 fatty acid (5.9-14.8% of fatty acids). Docosatetraenoic and docosapentaenoic acids of the omega 6 series accounted for 3-8% of the total fatty acids. The ratio of omega 6 to omega 3 fatty acids in these fish varied from 0.38 to 0.93, compared with an average ratio of 0.16 for fish from the northern hemisphere (latitude greater than 30 degrees N). The present data and figures from the literature indicate that the marine food chain in the southern hemisphere contains significant quantities of omega 6 fatty acids.

Animals↗
PubMed1983

Differentiation of meat according to species by the electrophoretic separation of muscle lactate dehydrogenase and esterase isoenzymes and isoelectric focusing of soluble muscle proteins.

Species identification of fresh meat can be readily achieved by serological techniques with the limitation that closely related species, such as sheep/goat, cattle/buffalo and horse/donkey, cannot be differentiated. We have examined electrophoretic techniques with particular reference to the identification of meat from closely related species. The results showed that beef and buffalo meat and meat from red and grey kangaroos could be clearly distinguished by isoelectric focusing on polyacrylamide gel or agarose in the pH range 5.5 to 8.5. Sheep and goat meat, and horse and donkey meat could not be differentiated by this technique, but were clearly distinguished from each other by their esterase isoenzyme profiles obtained after electrophoretic separation on cellulosic membrane strips. Results from this latter technique were available in one hour. We believe that species identification of fresh meat should involve an initial screening test by serological techniques followed by confirmation of the identity of suspect samples by electrophoretic techniques.

Animals↗
PubMed1983

Control of alpha-mannosidosis in Angus cattle.

Tests for the detection of animals heterozygous for alpha-mannosidosis were undertaken on samples taken from 34,203 cattle registered with the Angus Society of Australia. Results indicates 1,836 (5.4%) of the animals were heterozygotes. Heterozygotes were detected in 214 (51%) of the herds examined.

Animals↗
PubMed1982

Pharmacokinetics of meptazinol in man following repeated intramuscular administration.

A study was performed in 6 healthy volunteers to determine whether 50 mg intramuscular doses of meptazinol repeated four hourly for 24 h would lead to accumulation of the drug. The first dose of meptazinol was rapidly absorbed with a subsequent mean (+/- SD) elimination half-life of 1.6 +/- 0.33 h. This value was unaffected by the administration of intermediate doses. There was no significant accumulation of the drug; 95% of the steady-state plasma concentration was achieved after a mean (+/- SD) of 1.9 +/- 0.39 and 99% after a mean (+/- SD) of 2.9 +/- 0.63 doses. These findings are consistent with the theoretical prediction for a rapidly absorbed drug with a plasma elimination half-life of 1.6 h. No clinically relevant changes were seen in pulse blood pressure, haematological or biochemical screens. Reported side effects were of a subjective and minor nature.

Adult↗
PubMed1982

The blood-brain barrier in rats fed on diets high or low in saturated/unsaturated fat ratio.

The product of the permeability x vascular surface rate area (PA) of the blood-brain barrier to [14C]sucrose has been measured in rats raised on synthetic diets in which the saturated/unsaturated fat constitution was controlled at high or low levels. Gas-liquid chromatography demonstrated marked differences in brain fatty acid constitution between the dietary groups. No statistically significant differences was found between the permeability measurements in rats maintained on any of the synthetic diets, nor was there any difference from rats raised on a standard laboratory pellet food. The opportunity was taken to look at 3 other properties of brain that might be affected by lipid constitution. There was no change in the form of the membranous intracellular inclusions that can be induced by intracerebral injections of suramin, and Fink-Heimer staining of degenerating axons, which is inhibited by fat extraction, worked equally well on each diet group. The sleep time after an anaesthetic injection of alcohol was not significantly changed.

Animals↗
PubMed1982

Increased proportion of arachidonic acid in plasma lipids after 2 weeks on a diet of tropical seafood.

Using capillary GLC we analyzed the plasma fatty acids in a group of full-blood Aborigines in north western Australia before and after 2 wk on a diet in which over 90% of the energy was derived from tropical fish and shellfish. The proportion of saturated fatty acids did not change and all monoenoic and omega 6 fatty acids, except arachidonic, fell significantly. The proportions of arachidonic and all omega 3 PUFA rose significantly on the diet. This striking rise in arachidonic was evident in all lipid fractions (phospholipids, cholesterol esters, and triglycerides). Total triglycerides in fasting plasma fell from 1.32 to 0.61 mM after the diet while total cholesterol, which was low initially, did not fall significantly. Analysis of the fatty acids in lipid extracts from the tropical seafood eaten in the study revealed an arachidonic acid content ranging from 4.8 to 14.3% of the total fatty acids. The seafood contained almost no linoleic acid but was, as expected, a rich source of omega 3 fatty acids (13.6 to 31.0% of the total fatty acids). From these data we are able to conclude that seafood from tropical waters, unlike seafood from colder waters, is a natural source of polyunsaturated fatty acids from both the omega 6 and omega 3 series.

Animals↗
PubMed1981

Essential fatty acid deficiency and evidence for arachidonate synthesis in the cat.

1. There is controversy regarding the capacity of the cat to convert 18: 2 omega 6 to 20: 4 omega 6 and the ability of the essential fatty acid (EFA)-deficient cat to produce 20: 3 omega 9. 2. This paper reports the isolation and identification of 20: 3 omega 9 from kidney phospholipids of EFA-deficient cats. 3. The results suggest that the cat is capable of limited synthesis of 20: 4 omega 6 using a delta 5- and delta 8-desaturase.

Animals↗
PubMed1981

A comparison of fluorimetric and colorimetric methods for the determination of alpha-mannosidase activity in bovine plasma.

This paper compares both manual colorimetric and fluorimetric methods for the assay of acidic alpha-mannosidase activity in bovine EDTA plasma. The effect of variable blood volumes per 10 ml blood collecting tube has been investigated, and the colorimetric assay conditions adjusted (for example, zinc concentration in pre-incubation buffer) to cope with low blood volumes resulting in high EDTA/plasma ratios. We have shown that with non-haemolysed EDTA plasma samples, the two methods give similar results, but for haemolysed samples, the colorimetric method yields significantly lower results than those obtained fluorimetrically. Using the manual fluorimetric method, samples can be assayed more rapidly and simply than by using the colorimetric method. This provides definite advantages in a laboratory receiving variable numbers of samples, or which cannot afford the high cost of automated equipment.

Animals↗