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Biomedical subjects

A J Sinclair

Publications and source records attributed to A J Sinclair.

At least 181 records · Page 10Linked to original sources
PubMed1980

Globoid cell leucodystrophy in polled Dorset sheep.

Globoid cell leucodystrophy (Krabbe's disease) was diagnosed in two Polled Dorset sheep from a stud farm. Clinical signs were hind limb incoordination progressing to tetraplegia. Histologic changes in white matter of the brain were myelin destruction, loss of oligodendroglia, astrogliosis and accumulation of distinctive periodic acid-Schiff (PAS)-positive globoid cells. The activities of galactocerebroside beta-galactosidase, the lysosmal enzyme specifically deficient in globoid leucodystrophy, and of three other glycosidase enzymes were compared in brain tissue of one affected and six unaffected sheep. Activities of the three nonspecific glycosidases were similar in all seven brains. Galactocerebrosidase activity was similar in the six control sheep, but in the affected brain was less than 6% of the control mean.

Animals↗
PubMed1979

Metabolism of linoleic acid in the cat.

Cats fed a diet containing linoleate as the only polyunsaturated fatty acid showed extremely low levels of arachidonate in the plasma lipids, as well as an increase in linoleate, eicosadienoate and an unknown fatty acid. Administration of [1-14C]linoleic acid and [2-14C]eicosa-8,11,14-trienoic acid to cats showed that in the liver there was no conversion of the [1-14C] 18:2 to arachidonate, whereas there was significant metabolism of [2-14C] 20:3 to arachidonate. It was found when methyl-gamma-linolenate was fed to cats that the level of 20:3 omega 6 and 20:4 omega 6 in the erythrocytes increased significantly. These results show that there is no significant delta 6 desaturase activity in the cat, whereas chain elongation and delta 5 desaturase enzymes are operative. The unknown fatty acid was isolated from the liver lipids and shown to be a 20-carbon fatty acid with 3 double bonds and which by gas liquid chromatography could be separated from 20:3 omega 9 and 20:3 omega 6. The presence of the delta 5-desaturase activity and the results of the ozonolysis studies indicated that this unknown fatty acid was eicosa-5,11,14-trienoic acid.

8,11,14-Eicosatrienoic Acid↗
PubMed1979

An improved fluorimetric determination of alpha-mannosidase activity in bovine plasma.

This paper describes a manual fluorimetric method for the assay of acidic alpha-mannosidase activity in bovine plasma. The optimum conditions for the assay of this enzyme were studied. The assay method devised includes the addition of zinc to the substrate, which stimulates activity by approximately twofold, and reduces the optimum substrate concentration. This latter feature affords considerable cost saving in each test. We have also shown that the alpha-mannosidase activity in lithium heparin plasma, EDTA plasma and blood serum is the same whether the plasma/serum is separated from the cells/clot at 6, 20 or 25 hours after sample collection. This has eliminated the previous necessity of having to deliver whole blood samples to the laboratory within 6 hours of collection. Furthermore samples for the supplementary neutrophil assay can now be taken at the same time as those for the plasma test, and both samples forwarded together. The plasma alpha-mannosidase assay is a rapid and reliable screening test for the mannosidosis genotype and for detecting carrier animals. Carrying out this plasma assay in conjunction with the more definitive neutrophil assay provides a reliable method of distinguishing homozygotes and heterozygotes from normal animals.

Animals↗
PubMed1978

Recognition and successful management in pulmonary aspergillosis in leukemia.

Invasive pulmonary aspergillosis is a common fungal infection in the compromised host. The outcome has been generally poor and, until recently, most reports are derived from autopsy series. We report nine patients with leukemia and the characteristic clinical presentation of pulmonary infarction. There is histological evidence that infarction is due to fungal invasion of the pulmonary arterial system with distal hemorrhagic infarction, cavitation, and mycetoma formation. This complete evolution was detected in six patients, none of whom had previous cavitary pulmonary disease. Therapy included amphotericin B (9 patients), aerosolized nystatin (6 patients), and 5-fluorocytosine (5 patients). Complete resolution of the pulmonary lesions occurred in six patients with a subsequent median survival of 13.5 months (range: 5-32+ months). Three patients died with continuing pulmonary infiltrate. Despite the antifungal chemotherapy, resolution seemed to correlate best with recovery of circulating neutrophils.

Adult↗
PubMed1975

Incorporation of radioactive polyunsaturated fatty acids into liver and brain of developing rat.

The incorporation of radioactivity from orally administered linoleic acid-1-14C, linolenic acid-1-14C, arachidonic acid-3H8, and docosahexaenoic acid-14C into the liver and brain lipids of suckling rats was studied. In both tissues, 22 hr after dosing, 2 distinct levels of incorporation were observed: a low uptake (from 18:2-1-14C and 18:3-1-14C) and a high uptake (from 20:4-3H8 and 22:6-14C). In adult rats, the incorporation of radioactivity into brain lipids from 18:2-1-14C and 20:4-3H was considerably lower than the incorporation into the brains of the young rats. In the livers of the suckling rats, the activity from the 18 carbon acids was associated mostly with the triglyceride fraction, whereas the activity from the 20:4-3H8 and 22:6-14C was concentrated in the phospholipid fraction. In the brain lipids, the activity from the different fatty apid fatty acids, some of the activity in the 18:2-1-14C and 18:3-1-14C experiments was associated with 20 and 22 carbon polyunsaturated fatty acids; however, radioactivity from orally administered 20:4-3H8 and 22:6-14C was incorporated intact into the tissue phospholipid to a much greater extent compared with the incorporation of radioactivity into 20:4 and 22:6 in the experiments where 18:2-1-14C and 18:3-1-14C, respectively, were administered. Possible reasons for these differences are discussed. Rat milk contains a wide spectrum of polyunsaturated fatty acids, including linoleate, linolenate, arachidonate, and docosahexaenoate. During the suckling period in the rat, there is a rapid deposition of 20:4 and 22:6 in the brain. The results of the present experiments suggested that dietary 20:4 and 22:6 were important sources of brain 20:4 and 22:6 in the developing rat.

Animals↗
PubMed1975

The incorporation of orally fed radioactive gamma-linolenic acid and linoleic acid into the liver and brain lipids of suckling rats.

The incorporation of radioactivity from orally administered gamma-linolenic acid-1--14C and linoleic acid--3H into the liver, plasma, and brain lipids of suckling rats was studied. Significantly more radioactivity from the former compound was incorporated into the liver and brain lipids 22 hr after dosing. The distribution of the radioactivity in the fatty acids of the liver and brain lipids was different for each isotope. Most of the -3H was still associated with linoeic acid, whereas most of the -14C was in the 20:3 and 20:4omega6 fractions. These results suggest that the desaturation of linoleic to gamma-linolenic acid in vivo is a rate-limiting step in the conversion of linoleic to arachidonic acid.

Administration, Oral↗