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Biomedical subjects

J T Done

Publications and source records attributed to J T Done.

At least 37 records · Page 2Linked to original sources

Bovine virus diarrhoea-mucosal disease virus-induced fetopathy in cattle: Efficacy of prophylactic maternal pre-exposure.

Maternal immunity was produced in Jersey heifers by exposing them to bovine virus diarrhoea-mucosal disease virus before conception. In the following pregnancy this immunity protected the fetuses from transplacental infection arising from challenge of the dams at 100 days gestation with homologous virus. Unprotected Jersey heifers showed a high incidence of death and fetal intrauterine growth retardation associated with transplacental viral infection. Functional normality of the locomotor system was assessed retrospectively from ciné films of each calf after birth, and scored for each of an overlapping series of clinical signs. The progeny of non-immune dams scored significantly lower than calves from the vaccinated heifers.

Animals↗

Atrophic rhinitis: snout morphometry for quantitative assessment of conchal atrophy.

Morphometric methods, either point counting or semiautomated planimetry, can be applied to photographic or impression prints of sections of the pig snout to measure the extent of conchal atrophy on a continuous scale as a morphometric index. Though relatively time consuming, the technique yields highly repeatable parametric data which do not depend heavily on expert, subjective judgment. It is therefore particularly suitable for quantitative analysis of the effects of experimental treatments or changes in management.

Animals↗

Congenital tremor type AI: light and electron microscopical observations on the spinal cords of affected piglets.

The histology and ultrastructure of the spinal white matter from the dorsolateral funiculus of the third cervical segment was studied in normal control pigs and pigs whose dams were inoculated with the Weybridge congenital tremor strain of swine fever virus in early pregnancy. Only inoculated sows produced abnormal piglets. These showed congenital tremors and ataxia. The severity of clinical signs was related to the degree of spinal myelin deficiency. Morphologically this was quantified by determination of the thickness of myelin investing axons classed according to their diameter. In clinically affected pigs fewer axons were myelinated than normal. Though the myelin sheath thickness increased with increasing axon diameter in all pigs whether clinically normal or not, the increase was less in moderately affected and much less in severely affected pigs. The deficiency of spinal myelin was probably due to delayed or sub-normal myelination accompanied by paranodal myelin abnormalities, myelin degeneration and remyelination.

Animals↗

Bovine virus diarrhoea-mucosal disease virus: pathogenicity for the fetal calf following maternal infection.

Fifteen pregnant, bovine virus diarrhoea-mucosal disease (BVD-MD) antibody-free Jersey heifers were infected experimentally with a mixture of 10 cytopathic strains of BVD-MD virus isolated from cattle in Britain. Each cow was inoculated intramuscularly on gestation day 100 with a high or a low dose of virus grown in primary calf testis tissue cultures. None of the cows showed clinical signs of illness following exposure, but all had seroconverted within six weeks. Six fetuses, including one set of twins, died in utero following infection. Of these five were aborted between days 136 and 154; the sixth one was mummified and still retained at day 300. The remaining 10 fetuses survived to term, but all showed evidence of intrauterine growth retardation with or without gross malformation and/or dysmyelination of the central nervous system. Three were clinically affected with congenital nervous disease. Of the 10 liveborn fetuses, two had specific serum antibodies to BVD-MD. Non-cytopathic BVD-MD virus was recovered from all of the remaining eight. When non-immune cows become infected with BVD-MD virus in mid gestation: transplacental infection of the fetus will probably result; apart from the risk of fetal death, with or without abortion, there is a high probability of fetal mal-development which may not always be clinically obvious; the immunological competence of the fetus may be impaired; congenital infection is likely in a substantial proportion of liveborn calves. About one in 16 bovine fetuses in British herds are estimated to be at risk from BVD-MD virus infection.

Abortion, Veterinary↗

Rhinitis of pigs: A gross staining method for macroscopic examination of the nasal mucosa.

A phloxine-alcian blue (PhAB) method has been used to stain the porcine nasal mucosa for macroscopic examination. Applied to either fresh or fixed specimens it stains respiratory epithelium dark blue and non-cilated epithelium, including the metaplastic epithelia of rhinitis, bright pink. The PhAB technique is simple, inexpensive and dependable, and is suitable for routine application in the post mortem room. Stained and fixed specimens may be preserved virtually indefinitely.

Alcian Blue↗

Porcine atrophic rhinitis: snout radiography as an aid to diagnosis and detection of the disease.

Snout radiography is a useful and practicable aid to the diagnosis of atrophic rhinitis. It is also a fairly reliable means of detecting and measuring turbinate atrophy and distortion of the septum nasi in the live pig. Suitable physical and pharmacological methods of restraining pigs for snout radiography are described and guide lines for producing satisfactory, standard snout radiographs are given. Parameters and criteria are recommended for qualitative and quantitative methods of interpreting snout radiographs. The quantitative scoring system approximates the macroscopic post mortem snout scoring system generally employed in Britain and provides data which might be used in genetic or other control programmes. Radiographic standards are tentatively suggested for certifying pigs free from gross lesions of atrophic rhinitis for sale or export purposes.

Anesthesia, General↗

Neuropathology of experimental swine vesicular disease in pigs.

A total of 26 young pigs were inoculated intracerebrally, intravenously or intradermally with the UKG27/72 strain of SVD virus, grown in tissue culture, and killed two, four, eight or 16 days after exposure. Overt nervous symptoms were seen only in pigs inoculated intracerebrally, but all pigs of all groups showed a non-suppurative meningitis and panencephalomyelitis principally affecting the mid- and fore-brain. Ganglioneuritis with intranuclear inclusion bodies in perineuronal amphicytes were found to be the most consistently useful characters for distinguishing SVD from other virus encephalitides of pigs. Spinal radiculitis was a feature of the early stages of CNS involvement and lesions were found also in the optic nerve, retina and cornea.

Animals↗

Asymmetric hindquarter syndrome (AHQS) in the pig.

Outbreaks of the asymmetric hindquarter syndrome (AHQS) in two pig herds are reported together with the results of test matings and dissection studies on affected pigs. The condition (apparently identical with that described in Germany in 1967), is characterised by a variable asymmetry of the hindquarters and particularly of individual muscles of the posterior, lateral and medial aspects of the thigh. It does not noticeably interfere with locomotion but can adversely affect carcase conformation and may detract from the usefulness of carcase dissection studies as a basis for genetic selection. AHQS has a familial incidence and is usually first detected clinically after weaning. A variety of degenerative and dystrophic changes have been seen in the muscles of AHQS pigs but these are not constantly present in nor confined to 'undersized' muscles. The precise aetiology of AHQS is still unresolved but it is concluded that it probably occurs post-natally and that some pigs have a genetic liability to develop the condition.

Animals↗