Biomedical subjects

N E Reed

Publications and source records attributed to N E Reed.

11 recordsLinked to original sources

PubMed2000

The maintenance of challenge strains used in the potency test for canine leptospira vaccines.

The challenge test for leptospira vaccines required by most licensing authorities is difficult to standardise and unreliable. One of the main contributory factors to this, is the difficulty in maintaining the virulence of the challenge strain. This paper describes work carried out to assess the practicality of storing challenge strains of Leptospira canicola and Leptospira icterohaemorrhagiae in liquid nitrogen. The effects of different concentrations of glycerol and dimethyl sulphoxide on the recovery of virulent and avirulent strains of Leptospira canicola and Leptospira icterohaemorrhagiae were investigated. Concentrations of cryopreservant above 5% increased the time taken for the leptospires to grow after recovery from vials stored in liquid nitrogen. In addition, the virulence of five challenge strains were shown to be little affected after 18 passages in vitro.

Animals↗

PubMed1997

Diagnosing congenital heart defects using the Fallot computational model.

This paper describes a computational model developed for the diagnosis of multiple defects. If multiple defects interact, meaning that the cues observable for multiple defects are not a sum of the cues observable for the component defects, diagnosis is particularly difficult. We developed a description and classification of the ways cues change when defects interact. A computational model (named Fallot) was implemented and a knowledge-base was constructed for the diagnosis of congenital heart defects. On each case, Fallot performs recognition-based reasoning followed by solution construction and evaluation with the cue combination methods. Fallot was tested on cases from hospital files and correctly diagnoses cases with multiple interacting defects for which conventional methods are not applicable or fail.

Abnormalities, Multiple↗

PubMed1989

An international collaborative study of an anti-infectious bursal disease virus reference serum.

Fourteen laboratories participated in a collaborative study of a freeze-dried preparation of anti-infectious bursal disease virus serum to assess the suitability of the serum as a standard for use in the infectious bursal disease virus neutralization test. Ten laboratories carried out micro-virus neutralization tests and six carried out plaque reduction tests, two laboratories carrying out both tests. When titres were expressed as a proportion of that obtained for a reference preparation there was a marked reduction in variation between results from different laboratories. The use of a reference preparation was therefore of value when comparing results from different laboratories. It is proposed that the reference preparation used in this study be used as a standard to facilitate the comparison of results from different laboratories. The proposed standard contains by definition 10,000 UK units.

Animals↗

PubMed1985

Increased virulence of an infectious bursal disease live virus vaccine after passage in chicks.

A live infectious bursal disease virus vaccine increased in virulence when passaged six times in susceptible birds, as judged by damage to the bursa of Fabricius. It is suggested that the increase in virulence of this vaccine was due to the selection of a virulent subpopulation which had been present in the vaccine since its original isolation from the field and which had not been eliminated during its attenuation by passage in cell culture. The vaccine was then plaque purified and a virus strain was selected which protected against challenge, did not damage the bursa and appeared not to passage in birds.

Animals↗

PubMed1985

Detection of antibodies against infectious bursal disease virus: a comparison of three serological methods.

Four different oil emulsion infectious bursal disease virus (IBDV) vaccines were inoculated into four-week-old specific pathogen-free chickens. At weekly intervals for five weeks, sera were obtained from the vaccinated birds and from uninoculated control birds and examined for antibodies against IBDV by enzyme-linked immunosorbent assay (ELISA), the quantitative agar gel precipitin (QAGP) test and the virus neutralisation (VN) test. There was a highly significant correlation between the mean responses to all tests; the highest correlation (0.818) was between VN and QAGP and the lowest (0.573) between QAGP and ELISA. Generally the ELISA detected positive sera earlier than the VN test which in turn was more sensitive than the QAGP test. The ELISA and QAGP test were less variable, more reproducible and easier to perform than the VN test.

Animals↗

PubMed1984