Biomedical subjects

O Grahl-Nielsen

Publications and source records attributed to O Grahl-Nielsen.

13 recordsLinked to original sources

PubMed2001

The redfish species Sebastes viviparus, Sebastes marinus and Sebastes mentella have different composition of their tissue fatty acids.

The fatty acid profile in the tissue of heart, gill, skull- and otolith-oil of the three redfish species, Sebastes viviparus, S. marinus and S. mentella was determined by a chemometric method, consisting of methanolysis of samples of the tissues and of the oils and gas chromatography of the resulting fatty acid methyl esters. The analytical data were treated by multivariate statistics comprising principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). Although the differences in fatty acid composition among the two tissues and two oils were the dominating features of the data, the three species had significantly different fatty acid profiles within each tissue. Variation among the individuals was considerable. The fatty acid profiles appeared to be species specific. The mutual relationship between S. marinus and S. mentella is closer than the relationship between either of them and S. viviparus. A comparison with a corresponding investigation on the same three species from another location indicates that the observed differences do not seem to be affected by biotic or abiotic factors.

Animals↗

PubMed2000

Trace element levels in harp seal (Pagophilus groenlandicus) and hooded seal (Cystophora cristata) from the Greenland Sea. A multivariate approach.

Concentrations of the essential trace elements, iron, copper, zinc and selenium and the non-essential elements arsenic, cadmium, total mercury and lead, were measured in the meat, liver and kidney of two species of seals, harp seal (Pagophilus groenlandicus) and hooded seal (Cystophora cristata) collected in the Greenland Sea. The spread among the individual seals was considerable. However, multivariate statistics simplified the evaluation of the data. The muscle tissue contained lower levels of the elements than kidney and liver. The kidney and liver tissue were also different, in particular with higher levels of iron in the liver and higher levels of cadmium in the kidney. Species differences were clear in both liver and kidney tissue, with higher levels of most of the elements in the hooded seals, while the harp seals had a higher burden of arsenic in the two tissues. Male hooded seals had higher levels of mercury and selenium than the females in all tissues. For harp seal there was a slight difference between the sexes in the muscle tissue, while no difference was observed in the liver and kidney tissues. The juvenile seals generally had lower levels of the elements in their tissues than the adults, although copper and zinc were higher in the muscles and livers of the juveniles as was iron in the muscles. No correlation between age and trace element levels in the tissues of the adult seals was observed.

Age Factors↗

PubMed2000

Transfer of fatty acids from female seal blubber via milk to pup bladder.

Fatty acids were determined by gas chromatography followed by principal component analysis (PCA) and soft independent modelling of class analogy (SIMCA) in the blubber of 18 female grey seals, Halichoerus grypus, in their milk and in the blubber of their 1-week-old nursing pups. Large individual differences were observed in both blubber and milk content of fatty acids. The fatty acid composition of the milk was systematically different from the composition in maternal blubber, with higher relative amounts of the saturated acids, the monounsaturated with 20 carbon atoms and the n3 polyunsaturated, except 18:3n3. The composition of the fatty acids in the blubber of the pups was different from that of the milk. The same fatty acids that were enriched in the milk were depleted in the blubber of the pups. Therefore the fatty acid composition in the blubber of the pups was similar to that in the adults, although not identical. The results from this investigation imply that the composition of the fatty acids in the blubber of female seals and in the blubber of their pups cannot be determined directly by analysis of fatty acid composition of milk.

Adipose Tissue↗

PubMed2000

Discrimination of Sebastes viviparus, Sebastes marinus and Sebastes mentella from Faroe Islands by chemometry of the fatty acid profile in heart and gill tissues and in the skull oil.

The composition of fatty acids in the tissue of heart, gill and skull oil of the three redfish species, Sebastes viviparus, Sebastes marinus and Sebastes mentella was determined by a chemometric method. The method consists of methanolysis of samples of the tissues and of the oils, gas chromatography of the resulting fatty acid methyl esters and multivariate statistical treatment, by principal component analysis, of the analytical data. Although the differences in fatty acid composition among the three tissues were the dominating features of the data, the three species had significantly different fatty acid profiles within each tissue, even though variation among the individuals was considerable. The fatty acid profiles appear to be species specific. The mutual relationship between S. marinus and S. mentella is closer than the relationship between either of them and S. viviparus.

Animals↗

PubMed1989

Determination of benzenes and naphthalenes in water by purge and trap isolation and capillary column chromatography.

A method for determination of volatile, aromatic hydrocarbons in the range from benzene to C2-naphthalenes has been adapted for monitoring the concentration of these components in water. The hydrocarbons are purged from the water by helium, trapped on an adsorbent, Tenax-GC, desorbed from this by rapid heating, transferred directly to a fused-silica gas chromatography column, which is cooled to -80 degrees C for initial cryotrapping, and finally chromatographed by programmed raising of the temperature of the column. The whole process is automated and takes 40 min, plus 10 min for temperature equilibration for the next experiment. With 5 ml water samples, concentrations of 0.1 microgram/l (ppb) of the individual components were determined. The method was applied to monitoring of a biotest system, and compared to the traditional liquid extraction method.

Benzene↗

PubMed1975

Gas chromatography and mass spectrometry of derivatives of amino acids. Oxazolin-5-ones of several acyl-leucines.

By the action of dicyclohexylcarbodiimide on fourteen different acyl-leucines in ethyl acetate solution, the corresponding oxazolin-5-ones were formed. The reaction was quantitative and very rapid. The oxazolin-5-ones were separated on a gas chromatograph on OV-7 and EGA columns. The mass spectra of the oxazolin-5-ones showed characteristic fragments that could be used for identification.

Acylation↗

PubMed1975