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Biomedical subjects

B Rushton

Publications and source records attributed to B Rushton.

14 recordsLinked to original sources
PubMed1979

Inability of passively acquired antibody to protect lambs against experimental pasteurellosis.

An experimental model of pneumonic pasteurellosis in sheep was used to investigate the role of serum antibody in resistance to this disease. Lambs which had been vaccinated with a sodium salicylate extract of Pasteurella haemolytica type A1 were protected against challenge with PI3 virus followed by P. haemolytica type A1 7 days later. The majority of untreated lambs and lambs which had received either 200 ml of antiserum to P. haemolytica or 200 ml of control serum intraperitoneally 18 h before infection with P. haemolytica type A1 succumbed to the challenge. Lymphocytes from vaccinated lambs showed a specific proliferative response when exposed to P. haemolytica type A1 sodium salicylate extract, and this response increased after exposure of these animals to P. haemolytica type A1 in aerosol. The results indicate that the humoral immune response alone is incapable of affording protection against experimental pasteurellosis and that cell-mediated immunity may play an important part in resistance to this disease.

Animals↗
PubMed1978

Intrahepatic vascular lesions in experimental and natural ovine fascioliasis.

Using acrylic resin casts prepared from the liver vasculature and histology, subdivisions of the portal and hepatic systems stenosed as a result of experimental and natural infections of F. hepatica were identified as terminal, secondary and tertiary portal veins and central and sublobular hepatic veins; primary portal veins were also involved in the experimentally infected livers. Fewer veins tended to be involved in livers naturally-infected and they were more evenly distributed among liver lobes than in the experimental disease where most were found in the ventral lobe. Casts of both types of infection also demonstrated enlargement and tortuosity of arteries in ventral lobes and those forming the peribiliary arterial plexus, as well as showing that multiple anastomotic channels had formed. The arterial changes and anastomoses were suggested as developing to compensate for the effects of vascular stenosis. Portal vein stenosis induced experimentally was the outcome of replacement of eosinophils and oedema-like fluid present in veins around fluke tracks and of the organisation of fluke tracts impinging upon veins. During the post-migratory period of infection, stenosis became more marked, for which no adequate cause was identified. In livers naturally-infected, in addition to stenosed portal and hepatic veins, vascular channels in collagen septa in sinusoids and a slight convolution of arteries were seen.

Animals↗
PubMed1978

Ovine pneumonia.

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Animals↗
PubMed1977

Structure of nucleosome core particles of chromatin.

Cystals have been obtained on nucleosome cores and analysed by X-ray diffraction and electron microscopy. The core is a flat particle of dimensions about 110 X 110 X 57 A, somewhat wedge shaped, and strongly divided into two 'layers', consistent with the DNA being wound into about 1 3/4 turns of a flat superhelix of a pitch about 28 A. The organisation of the DNA can be correlated with the results to enzyme digestion studies. A change in the screw of the DNA double helix on nucleosome formation can be deduced.

Animals↗
PubMed1977

Pathology of ovine adenovirus type 4 infection in SPF lambs: pulmonary and hepatic lesions.

Seven lambs were challenged with an aerosol of OA4 virus. Four developed mild pulmonary oedema and a sparse accumulation of mononuclear cells around blood vessels similar to results reported previously. In addition, three had focal hepatic necrosis and one of these three had a non-suppurative occlusive cholangitis and portal tract lymphangitis and thrombosis. Basophilic intranuclear IB's were identified in many necrotic hepatocytes, in lymphatic endothelial cells involved in thrombi but in only one bile duct epithelial cell. Ultrastructurally, virions with the characteristics of adenovirus were seen in hepatocytes. Although only one IB was seen in the affected biliary system there was no evidence that it was caused by an agent other than OA4. Virus was considered to infect the respiratory system directly, be swallowed to infect the alimentary system and carried, possibly within cells, via a haematogeneous and/or lymphogenous route to the liver. The effect of naturally acquired virus on sheep is unknown but it is possible that it may predispose the host to more serious infections.

Adenoviridae↗
PubMed1977

Ovine fascioliasis following reinfection.

Sheep were reinfected with matacercariae once. Half were treated with anthelmintic one week before reinfection. Compared with a primary infection, the reinfecting flukes in most seemed to migrate faster through the liver although in one treated sheep migration seemed to be longer and more destructive. Migrations extended into areas little affected by the primary infection thus producing more widespread fibrosis. Although a temporary retardation in fluke growth rate occurred, there was no reduction in the numbers of flukes recovered. Flukes killed by anthelmintic formed large granulomata.

Animals↗
PubMed1976

The assessment in sheep of an inactivated vaccine of parainfluenza 3 virus incorporating double stranded RNA (BRL 5907) as adjuvant.

The serological responses of conventionally reared sheep were compared after vaccination with inactivated parainfluenza 3 (PI3) virus incorporated in three different adjuvants. Inactivated PI3 virus with the double-stranded RNA, BRL 5907 in an oil emulsion was shown to stimulate higher serum antibody titres over the first 5 weeks after vaccination than virus with and without BCG emulsified in oil. The ability of this vaccine to protect specific pathogen-free lambs against challenge with PI3 virus was examined in a second experiment. In this experiment the vaccine stimulated virus neutralizing and haemagglutination inhibiting antibodies in the serum. After intranasal and intratracheal inoculation with PI3 virus at challenge, vaccinated lambs showed no clinical illness and virus isolation was confined, except in one lamb, to the first two days. In contrast, unvaccinated lambs developed respiratory disease and virus was isolated daily for 7 days after challenge.

Adjuvants, Immunologic↗
PubMed1976

Morphology and classification of subdivisions of the intrahepatic vascular and biliary systems in sheep.

Tensol casts and histology were used to demonstrate sub-divisions of the portal and hepatic veins, and arterial and biliary systems. Portal and hepatic venous subdivisions were most readily identified. Based upon size, location, sequence of branching and histological characteristics a nomenclature for the sub-divisions of the portal vascular system was proposed. The names of distributing, primary, terminal, secondary (long and short) and tertiary veins were adopted to identify portal veins branches. The same criteria allowed the identification of three hepatic vein branches, central, sublobular and hepatic; the central hepatic veins and to a much lesser extent the sublobular hepatic veins drained the sinusoids. Casts of the arterial system demonstrated the arterial blood supply to the biliary system, to the sinusoids and portal vein vasa vasorum but they were of little use in identifying subdivisions. Arterial subdivision identification is possible by using accompanying portal veins as morphological markers and designating the subdivision after the vein. This approach is also applicable to the biliary system and provides a more accurate means of subdivision identification than does the broader division into ductules, intermediate and large ducts.

Animals↗