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Biomedical subjects

D R Shafren

Publications and source records attributed to D R Shafren.

21 records · Page 2Linked to original sources

Further evidence that the nucleic acid of avian encephalomyelitis virus consists of RNA.

The nucleic acid of the Van Roekel strain of avian encephalomyelitis virus (AEV) was determined to be RNA, according to the inability of the nucleoside analog 5-bromo 2'-deoxyuridine (BUdR) to inhibit its growth in chicken embryo kidney cell cultures. The test was carried out using known DNA and RNA viruses as controls, and the results are consistent with classification of AEV as a member of the family Picornaviridae within the genus Enterovirus.

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An enzyme-linked immunosorbent assay for the detection of avian encephalomyelitis virus antigens.

An enzyme-linked immunosorbent assay for detection of the antigens of avian encephalomyelitis viruses (AEVs) was developed, using an antigen capture method with affinity-purified anti-AEV immunoglobulins prepared in rabbits. Both the Van Roekel strain and a field strain of AEV could be detected at concentrations of 4 x 10(3) ng/g tissue in the presence or absence of an uninfected chicken embryo extract. The procedure was used to determine the distribution of antigens to the Van Roekel strain after inoculation of 6-day-old chicken embryos. Antigen concentrations were highest in the embryo brain and lower in the heart and other tissues. When the same strain was inoculated intramuscularly into day-old chickens, highest levels of antigen were noted in the pancreas, gizzard, and brain. Patterns of fecal antigen excretion and antibody production were studied after inoculation of the field strain by the intramuscular, intracerebral, and oral routes. Excretion was most prolonged following oral inoculation (4-10 days), although antigen could be detected by 2 days after intracerebral inoculation. Detectable antibody was present by 10 days following infection by each route.

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A rapid procedure for the purification of avian encephalomyelitis viruses.

A rapid procedure for the purification of egg-grown or field preparations of avian encephalomyelitis virus (AEV) of neural origin is described. Extracts of infected tissues were clarified and then partly purified with trichlorotrifluorethane (Freon TF), and the virus present was concentrated with polyethylene glycol. The concentrates were then re-extracted with Freon, and a portion was labeled with 125iodine. During subsequent purification steps, virus could be readily detected by monitoring for radioactivity, thus eliminating the need to determine the infectivity in individual fractions or to examine for the presence of virions by electron microscopy. Final purification was achieved by cesium-chloride equilibrium or sucrose-velocity-gradient centrifugation. Virus purified in this manner was shown to be free of tissue debris, to be specific for AEV by immune electron microscopy, and to possess structural proteins characteristic of picornaviruses.

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