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Biomedical subjects

A J Forman

Publications and source records attributed to A J Forman.

At least 37 records · Page 2Linked to original sources
PubMed1982

Susceptibility of bovine macrophages to infectious bovine rhinotracheitis virus infection.

Infectious bovine rhinotracheitis virus replicated in cultured bovine alveolar macrophages (AM). However, yields of infectious virus were low, with maximum titers approximately 100 times that of the residual inoculum. Immunofluorescence and electron microscopic studies indicated that the majority of macrophages produced viral antigen, but after infection at a multiplicity of 0.1, only 4.1% of AM produced infectious centers. Virus-infected AM culture supernatants possessed interfering activity, probably due to interferon. Incubation of fresh AM with these fluids rendered them refractory to infection. Although AM from infectious bovine rhinotracheitis virus-immune and -susceptible donors were equally permissive and their susceptibility was unaltered by incubation with bacterial lipopolysaccharide, bovine mammary macrophages which were elicited with lipopolysaccharide became nonpermissive when further incubated for 48 h with 1 microgram of lipopolysaccharide per ml. Under these conditions, infected mammary macrophages failed to synthesize viral DNA, and there was reduced synthesis of "late" viral polypeptides.

Animals↗
PubMed1982

The immunogenicity of K99 antigen in whole cell bacterins of Escherichia coli.

K99 antigen in Escherichia coli whole cell bacterins was immunogenic in rabbits and mice. Mice vaccinated subcutaneously and bled three weeks later had a serum antibody response which was dose dependent. The dose response on dilution of bacterins was shown to be mainly due to dilution of K99 antigen, rather than the reduction in adjuvant or bacterial cell concentration. The procedure appears to be a satisfactory one for immunogenicity testing of bacterins containing K99 antigen.

Adjuvants, Immunologic↗
PubMed1982

Effect of infectious bovine rhinotracheitis virus infection of calves on cell populations recovered by lung lavage.

Calves were challenge exposed with infectious bovine rhinotracheitis (IBR) virus, and experiments were carried out to determine the presence of virus in the lungs, virus or viral antigen in alveolar macrophages, and alterations in immune functions of alveolar macrophages. In experiment 1, calves were challenge exposed intranasally with IBR virus. Although clinical signs of IBR occurred in all challenge-exposed calves, there was minimal evidence of virus or viral antigen in cells lavaged from their lungs, and macrophage Fc- and complement-receptor activities, phagocytic activity, and ability to mediate antibody-dependent cell cytotoxicity were unaltered. In experiment 2, calves were challenge exposed intranasally or by aerosol with IBR virus strains Colorado-1 and 108, and samples were collected 4 and 6 days after challenge exposure. Virus was isolated from the lungs, and pathologic lesions of greater severity occurred in those calves challenge exposed by aerosol. Less than 0.1% of lavaged cells from challenge-exposed calves produced infectious centers on susceptible cell monolayers. In 1 sample of lavaged cells, approximately 5% of the cells, mainly macrophages, had viral antigen in the cytoplasm, as detected by immunofluorescence. Because of the small proportion of macrophages that appeared to become infected after challenge exposure of calves with IBR virus, it is believed that the effect of IBR virus in predisposing calves to pneumonic pasteurellosis is an indirect, rather than a direct, manifestation of viral infection of macrophages.

Animals↗
PubMed1979

Atypical porcine enterovirus encephalomyelitis: possible interraction between enteroviruses and arsenicals.

Porcine enteroviruses were isolated from weaner pigs that had nervous signs and mild non-suppurative meningoencephalomyelitis and ganglioneuritis. The clinical signs and lesions were not typical of enterovirus infection and it is believed that an organic arsenical present in feed enhanced pathogenicity of enteroviruses. Severe non-suppurative polioencephalomyelitis and ganglioneuritis were produced in gnotobiotic pigs by oral inoculation of the viruses.

Animals↗
PubMed1978

Experimental infection of 35, 50 and 60 day old pig foetuses with porcine parvovirus.

Foetuses of six seronegative gilts, two of which each respectively 35, 50 and 60 days pregnant, were inoculated intrauterinely with porcine parvovirus (PPV) and examined 7 and 11 days after inoculation. HI antibody was not detected in any of the foetuses although all but one gilt developed low levels of antibody. All but one of the foetuses inoculated with PPV died in utero prior to examination at 11 days after inoculation. Infection also spread to non-inoculated litter mates. Histological changes were mild in the gilts but there was widespread tissue necrosis in infected foetuses, and intranuclear inclusion bodies were observed in cells of the liver, lung, kidney and cerebellum. The increased survival of foetuses infected at later stages of gestation appeared to be related to increased numbers of mononuclear cells then present in many tissues.

Animals↗
PubMed1977

The use of preserved milk samples in the Brucella milk ring test.

Brucella milk ring tests (BMRT's) were performed on fresh herd milk samples and pooled samples, preserved at a processing factory with potassium dichromate. Preserved milk from samples pooled over a 10-day period, gave results that were similar to an average result for individual fresh daily samples over the same period. When fresh samples gave variable results and the pooled preserved sample gave a negative result, it was considered that the latter result was more reliable, possibly due to factors causing false positive reactions being diluted. Blood testing of herds for circulating antibody indicated that the use of either fresh or preserved milk samples could occasionally produce false negative or false positive results.

Agglutination Tests↗
PubMed1975

A comparison of some immunological methods for the differentiation of strains of foot-and-mouth disease virus.

Two FMDV strains which had been previously differentiated by complement-fixation were compared by guinea-pig protection test, kinetic neutralization and micro-neutralization tests. It was found that these tests, which have not been previously applied by the methods described, were all capable of FMDV strain differentiation. Similar differences were found by all methods, which suggests that comparisons made by cross-CF, cross-neutralization or cross-protection involve measurement of the same antigen/antibody interactions.

Animals↗
PubMed1975

The sub-type classification of strains of foot-and-mouth disease virus.

Sixteen foot-and-mouth disease virus (FMDV) strains of type SAT 1 were compared in complement-fixation tests. With the test used, the range of antigenic variation within a type appeared to be greater than previously described. The concept of a sub-type group within which all strains are more closely related to each other than to any strain outside the group was not supported. Considering the group of strains studied, it is suggested that the classification of strains is best achieved by moninating a reference strain for each sub-type. Others are classified as related strains in one or more sub-type groups according to their relationships with the reference strains.

Animals↗
PubMed1974

A study of foot-and-mouth disease virus strains by complement fixation. I. A model for the fixation of complement by antigen-antibody mixtures.

An examination was made of the relations between antigen, antibody and fixation of complement with foot-and-mouth disease virus (FMDV). It was found that complement fixation in this system follows the same principles as models developed in other antigen/antibody systems. The assumption that there is a relation of direct proportionality between the amount of complement fixed and the amount of antiserum reacting with constant antigen was found to be incorrect. An alternative method was proposed for the quantitative differentiation of FMDV strains by comparing the titres of an antiserum when reacting with optimum amounts of homologous or heterologous antigens.

Animals↗
PubMed1974

A study of foot-and-mouth disease virus strains by complement fixation. II. A comparison of tube and microplate tests for the differentiation of strains.

Several foot-and-mouth disease virus strains were examined by complement-fixation tests in microplates and in tubes. It was established that the two systems are comparable, although greater reproducibility is obtained with tube tests. While microplate tests are a satisfactory method for the differentiation of strains, tube tests provide a more precise method for the identification of small antigenic differences.

Animals↗
PubMed1973

The Hampshire epidemic of foot-and-mouth disease, 1967.

An analysis was made of the spread of foot-and-mouth disease during the epidemic in Hampshire in January and February 1967. To explain the pattern of spread, it had to be postulated that virus was present seven days before the first outbreak was reported. It is suggested that the disease occurred initially in pigs fed on infected meat and that the virus was subsequently disseminated from the local abattoir, where the pigs were killed, to four farms by movement of animals, slaughterhouse waste, people or vehicles, and to fifteen by the airborne route. Subsequent spread from these farms was by movement in two instances and by the airborne route in five. The source and route of infection of the last farm in the outbreak were not determined.The risk of spread through movement was associated more with carriage of infected slaughterhouse waste, movement of animals, people or vehicles carrying animals than through collection of milk, artificial insemination or movement of other types of vehicles. Outbreaks of disease among pigs gave rise to more secondary spread than outbreaks in cattle. Secondary outbreaks attributed to airborne spread occurred only in ruminants. Most airborne spread was into areas of high livestock density and cattle in the larger herds became infected. Airborne spread could be correlated with wind direction and speed but not with rain. The reduction in the number of outbreaks at the end of the epidemic could be attributed to the elimination of the largest sources of virus, the control of movements and the fact that in all instances except two the wind was blowing virus over towns and out to sea, to areas of low stock density and to areas where animals had been killed.

Abattoirs↗