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Biomedical subjects

P Nansen

Publications and source records attributed to P Nansen.

At least 253 records · Page 14Linked to original sources
PubMed1981

Resistance to Fasciola hepatica in calves harbouring primary patent Schistosoma bovis infections.

A substantial resistance to a heterologous challenge with Fasciola hepatica was demonstrated in calves harbouring primary patent Schistosoma bovis infections of an age of 10 weeks at challenge, the mean worm burden being reduced by 29.9% (p less than 0.025) in calves primarily infected with S. bovis as compared with that of the challenge control group. The heterologous resistance was also evidenced by less pronounced liver tissue damage and lower serum gammaglutamyl-transpeptidase values in the S. bovis-infected animals compared with the challenge control group.

Animals↗
PubMed1981

Homologous immunotolerance and decreased resistance to Schistosoma mansoni in Echinostoma revolutum-infected mice.

Homologous immunotolerance was demonstrated in Echinostoma revolutum infections in the mouse. High-level infections of about 15 worms were not expelled for a period of at least 61 days following infection, whereas low-level infections of about 10 to 12 worms or below were eliminated completely between day 47 and 61 after infection. A primary, 20- to 33-day-old, heavy E. revolutum infection in the mouse produced a statistically significant increase in the number of Schistosoma mansoni recovered in challenge infections. Worm burdens increased by 65.7 to 90.6% as compared with those of the respective S. mansoni challenge control groups.

Animals↗
PubMed1980

Homologous and heterologous resistance in Echinostoma revolutum infections in mice.

Homologous and heterologous resistance in Echinostoma revolutum infections was studied in mice. A high level of homologous resistance was demonstrated in mice harbouring a 13-day-old primary E. revolutum infection with 9--10 and 11--15 worms, corresponding to a 70.0 and 66.7% reduction in the size of the established worm burden as compared with that of the challenge control group. A 14- and 20-day-old primary infection with 3--4 worms induced a level of resistance of 61.7 and 81.8% respectively, while higher worm levels of 9--10 and 11--15 induced almost complete resistance corresponding to a 95.1--100% reduction in the size of the established worm burden. Complete resistance was also demonstrated in mice challenged 8 days after elimination of a 20-day-old primary infection with 11--15 worms by anthelmintic treatment. A primary 43-day-old Schistosoma mansoni infection induced a 73.1% reduction in the size of the established E. revolutum challenge infection while infections of an age of 79 and 99 days conferred complete resistance to heterologous challenge with E. revolutum. Primary pre-patent S. mansoni infections and a patent S. bovis infection of an age of 56 days did not induce any resistance to challenge with E. revolutum. A primary 14- and 21-day-old infection of E. revolutum did not stimulate any significant level of resistance to heterologous challenge with S. mansoni.

Animals↗
PubMed1980

[A Danish pathography from the 17th century (Johan Valentin Wille) (author's transl)].

A monograph written by the physician Johan Valentin Wille in 1675 is discussed and commented. The monograph was published in Th. Bartholin Acta medica, the first medical journal in Denmark, and was in 1934 translated from Latin into Danish by the physician Eiler Høeg. It givees a detailed description of organ changes and internal parasites found in cattle and hare autopsied on Sealand 1674-75. Vermiform bodies found in the liver of cattle are undoubtedly identical with Fasciola hepatica. The tumorous or cystic formations in the bovine lung and liver correspond certainly with the larval stages of Echinococcus granulosus and the small cysts arranged as "bunches of grapes" on the liver surface and mesentery of hares cannot be anything else than Cysticercus pisiformis. It is possibly the first description of the mentioned parasites in animals in Denmark. The observations are published almost two centuries before the life-cycles of these parasites were finally clarified and about one century before the Danish Veterinary School was established at Christianshavn (in Copenhagen) and the founder Abildgaard started to publish his interesting observations on intestinal parasites.--The monograph is typical for that particular time, reflecting the decline of the medieval humoralism and the growth of the Renaissance science.

Animal Diseases↗
PubMed1979

[Not Available].

Explore the source record for details and available documents.

Denmark↗
PubMed1977

Stereoscan studies of rediae, cercariae, cysts, excysted metacercariae and migratory stages of Fasciola hepatica.

The external surface of the redial body of Fasciola hepatica is provided with microvillus-like projections or short lamellae, and short cilium-like structures are common anteriorly. The anterior part of the cercarial body possesses a pattern of regularly arranged small depressions each containing a spine. Both long and short cilium-like structures occur anteriorly. The tail is spineless and provided with dorsolateral folds. The outer cyst wall is formed by granules secreted from the tegument all over the body apart from the ventral sucker. Most granules transform into fibrillae which form the thick outer spongy layer. The precursor of the inner cyst wall is at the beginning closely attached to the metacercarial surface, but later the membrane-like cyst wall extends, and when fully formed the metacercaria lies free in the flattened circular inner cyst. The ventral plug is formed by the ventral sucker. The tegument of newly excysted metacercariae is provided with simple pointed spines, but later during migration in the mouse the spines become flattened and multipointed. Very young migratory stages may be attached with host cells.

Animals↗
PubMed1977

Interference with Fasciola hepatica snail finding by various aquatic organisms.

Previous studies using radioactive miracidia have shown that a number of non-host snails and bivalves, interposed as 'decoys' in linear test channels, may interfere with the capacity of Fasciola hepatica miracidia to infect Lymnaea truncatula. Applying similar experimental principles, the role of several other potential interferents have been analysed in the present study. Daphnia pulex (Cladocera) and larvae of Corethra sp. (Diptera) exercised significant interfering effects by protecting 'target' snails from infection. Evidence suggested that this effect was a result of their normal predatory behaviour. Other organisms including Herpobdella testacea and Helobdella stagnalis (Hirudinea), Acellus aquaticus (Isopoda), Planaria lugubris (Turbellaria) and L. truncatula egg clusters failed to interfere with miracidial host-finding. Nor did P. lugubris and L. truncatula 'conditioned water' interfere with the capacity of the miracidia to infect their host snail.

Animals↗
PubMed1977

[Fascioliasis in sheep in South-western Jutland (author's transl)].

The frequency of fascioliasis in sheep of south-western Jutland has been determined on the basis of slaughterhouse registration of infected livers over a 5-year period (1969-1973). The average yearly percentage of adult sheep found to be infected ranged from 83.9 to 91.2%, whereas less than 1 % of the slaughtered lambs proved infected. The high infection percentage among adult animals and the strikingly low frequency among slaughter lambs could be explained by the characteristic management system of the marshland: In summer the sheep graze the dike and the foreland on its seaward side, and in winter the animals graze in the marshland. Lymnaea truncatula is not found on or at the seaward side of the dike, whereas it is abundant all over the marshland. Thus the lambs graze exclusively the snail-free area from which they are taken directly to the slaughterhouse. The summer grazing also protects the adult animals as they avoid the massive uptake of metacercariae which normally takes place in fluke infected areas in late summer.

Abattoirs↗