The paradox that experiments in behavioural pharmacology employing nocturnal rodent species are carried out almost exclusively in the resting phase of the animals' circadian cycle has remained largely unexamined and unquestioned. This is despite the fact that all major physiological systems in the body are intrinsically aligned with its natural circadian rhythm. The forced-swim test (FST) is a rodent model that is used extensively as a screening test for antidepressant activity. The objectives of the present study were to examine the behaviour of rats in the FST under diurnal and nocturnal conditions and, in addition, to profile the response of neurochemical, neuroendocrine, and cellular indices of stress at time points up to 120 min following exposure to the FST. The time spent in escape-oriented activity was significantly less when animals were tested in the dark phase. The profile of serum corticosterone and adrenal ascorbic acid concentrations indicates that the animals were less stressed by the test situation during the active (i.e., dark) phase of their circadian cycle. Similarly, increases in blood enzymatic markers of stress-induced cellular damage were less marked following FST exposure in the nocturnal period. Characteristic stress-induced increases in 5-HT turnover in the frontal cortex and amygdala observed in the diurnal phase were reversed in the nocturnal period. In conclusion, circadian differences in behaviour in the FST may be related to parallel alterations in the ability of animals to adapt to exposure to stress.

Adrenal Glands↗

PubMedDate not supplied

Further studies on the classification of fowl adenoviruses.

In addition to the 8 fowl adenovirus serotypes described previously, 3 new serotypes were recognized. Two, A-2 and C2-B, were isolated in the U.S.A., and one, 380, in Northern Ireland. In addition another isolate, X-11, has a broader antigenicity than YR-36 and therefore should be used instead of YR-36 as prototype strain. It is concluded that there are at least 11 distinct fowl adenovirus serotypes on the basis of the serum-neutralization test.

Adenoviridae↗

PubMedDate not supplied

Production and preliminary characterization of monoclonal antibodies to chicken anemia agent.

Mice were immunized with partially purified preparations of the Cux-1 isolate of chicken anemia agent (CAA), and their splenocytes were fused with NSO myeloma cells. Three patterns of staining of CAA-infected cells were recognized when the resulting hybridomas were screened by indirect immunofluorescence (IIF). Hybridomas representative of each staining pattern were cloned, and the monoclonal antibodies (MAbs) were characterized. Type 1 staining was indistinguishable from that produced by polyclonal chicken antisera to CAA. Type 2 staining was confined to large nuclear inclusions. Type 3 staining was predominantly nuclear and granular, and differed from type 1 in being more intense and occurring in a higher proportion of nuclei. Three MAbs producing type 1 staining were predominantly Cux-1-specific by IIF; they also reacted to lower titers with the Gifu-1 isolate but not at all with three other CAA isolates. These MAbs had very slight neutralizing activity against Cux-1. Another MAb giving type 1 staining reacted with all CAA isolates tested to high titers in IIF and neutralization tests. MAbs with type 2 and type 3 staining reacted by IIF with all CAA isolates tested but possessed no neutralizing activity. The availability of MABs to CAA should facilitate development of diagnostic tests for the virus.

Animals↗

PubMedDate not supplied

Development of an enzyme-linked immunosorbent assay to detect serum antibody to chicken anemia agent.

An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to chicken anemia agent (CAA) has been developed. This test utilizes a CAA-specific mouse monoclonal antibody to selectively capture virus antigen. Chicken antibodies to CAA bind to the captured antigen and are detected with horseradish peroxidase-labeled anti-chicken immunoglobulin using a conventional indirect ELISA protocol. When 388 chicken sera from specific-pathogen-free and commercial flocks from the United Kingdom, West Germany, the United States and Australia were examined, 98.5% agreement was obtained between the results of the ELISA and the indirect immunofluorescence assay. This ELISA should have worldwide application in testing SPF and commercial chicken flocks for CAA antibodies.

Animals↗

PubMedDate not supplied

The experimental production of pneumonia in calves by intranasal inoculation of parainfluenza type III virus.

Thirteen colostrum deprived calves were inoculated with a low passage field strain of parainfluenza type III (PI 3) virus. Virus was administered by the intranasal route and the calves were experimentally infected twice daily for four consecutive days. Clinical signs of respiratory disease were noted and pneumonia was present in 12 animals at necropsy. PI 3 virus was isolated from the lung lesions and no other respiratory pathogens could be demonstrated. The pneumonic lesions grossly, histologically and in their distribution resembled those encountered in naturally occurring outbreaks of indoor calf pneumonia.

Animals↗

PubMedDate not supplied

Chicken anemia agent in the United States: isolation of the virus and detection of antibody in broiler breeder flocks.

Chicken anemia agent (CAA) was isolated from broiler chickens in Texas with a blue wing or anemia dermatitis-like syndrome. Specific-pathogen-free chicks inoculated with field material developed anemia, and CAA was isolated in MDCC-MSB1 cells from bone marrow and lymphoid tissue from inoculated chicks. One isolate, designated EF88/78/276, was further characterized. Infectivity of EF88/78/276 was resistant to treatment with chloroform and with heat at 70 C for 5 minutes. EF88/78/276 was indistinguishable from the Cux-1 and Gifu-1 isolates of CAA by cross-neutralization tests. Almost all 1-day-old susceptible chicks inoculated intramuscularly with EF88/78/276 developed anemia, but contact-infected chicks did not. Antibody to CAA was detected in broiler breeder flocks from Texas, the Delmarva peninsula, and Alabama.

Anemia↗

PubMedDate not supplied

Runting and stunting syndrome in turkeys.

A syndrome resulting in increased early deaths, runting and stunting in turkeys is described in 14 flocks at six sites in Ireland. Pathological lesions included bursal and thymic atrophy and mild degenerative changes in the pancreas of the affected poults. Entero-like virus, rotavirus, reovirus and adenovirus were detected in the affected poults and there was strong circumstantial evidence of lateral transmission of an infectious agent. Depopulation and thorough disinfection of affected houses appeared to eliminate the problem.

Animals↗

PubMedDate not supplied

Isolation of adenoviruses and reoviruses from avian species other than domestic fowl.

Adenoviruses and reoviruses were isolated from pigeons and mallard ducks. In addition, adenoviruses were isolated from budgerigars and a bantam and a reovirus was isolated from a turkey. Primary identification of these viruses was by electron-microscope examination. It was further possible to assign the 4 adenoviruses to recognized fowl serotypes, and the reoviruses shared a common antigen with fowl reoviruses. These viruses were isolated from a variety of clinical conditions.

Adenoviridae↗