PubMed Health⌕ Search

Biomedical subjects

R J Rogers

Publications and source records attributed to R J Rogers.

At least 37 records · Page 2Linked to original sources
PubMed1981

Pathology and tuberculin sensitivity in cattle inoculated with Mycobacterium avium complex serotypes 6, 14 and 18.

Three strains of Mycobacterium avium complex organisms, serotypes 6, 14 and 18 isolated from typical tuberculous lesions in cattle were examined for pathogenicity and ability to sensitise cattle to avian and bovine tuberculin. Each strain caused tuberculoid granulomas at the site of subcutaneous inoculation but no lesions elsewhere. Sensitisation to bovine tuberculin was detected in the caudal fold test in 11 of 18 inoculated animals 8 weeks after injection. In a simultaneous comparative cervical test, reactions to avian tuberculin were much larger than reactions to bovine tuberculin in all inoculated animals.

Animals↗
PubMed1980

Inhibition of cobalt(II) carboxypeptidase A by ligands. Kinetic evidence for the formation of a ternary enzyme-metal-ligand complex.

Saturation kinetics are observed in the inhibition of cobalt carboxypeptidase A by the chelating agent 1,10-phenanthroline. The association constant K1 for the formation of the enzyme-metal-ligand ternary complex and k2, the rate of breakup of the ternary complex, have been obtained. A mechanism is proposed to account for the pH profile of the reaction which, in conjunction with K1, permits the calculation of the individual rate constants k1, k-1, k2, k3. The magnitude of the rate constant k1 suggests that cobalt(II) in CoCPA is five-coordinate. Similar but less extensive studies on inhibition by 2,2'-bipyridyl and 8-hydroquinoline-5-sulfonic acid have also been carried out.

Animals↗
PubMed1980

The distribution of Mycobacterium bovis in Queensland cattle herds with observations on the laboratory diagnosis of tuberculosis.

Of 1,791 tissues submitted from 1975 to 1978 for histological examination for tuberculosis, 78.5% were classified as tuberculosis, 8.1% as club-forming granulomas, 3.3% as hydatid cysts, 3.4% as other granulomas and 2.4% as squamous cell carcinomas. Cultural examination of 2,682 tissues for mycobacteria yielded Mycobacterium bovis from 42.88%, other mycobacteria from 7.64% and 0.89% Rhodococcus (Corynebacterium) equi. Of 1,478 tissues on which both examinations were performed, culture and histology results were in agreement on 94.1%. M. Bovis was isolated on one or more occasions from 564 herds with the highest herd prevalence being recorded in western areas of the state. Culture of 1,024 tissues from no visible lesion (NVL) reactors yielded 0.59% M. bovis, 15.04% other mycobacteria and 0.19% R. equi. Of 120 isolates of other mycobacteria from tissues of NVL reactors, 39 were Runyon Group III (20 M.avium complex) and 61 Runyon Group IV. Approximately half of the herds from which NVL tissues were collected were confirmed M. bovis infected properties.

Actinobacillosis↗
PubMed1979

Evaluation of an indirect fluorescent antibody test to diagnose Babesia equi infection in horses.

An indirect fluorescent antibody (IFA) test for the diagnosis of Babesia equi infections was evaluated. Antigen prepared by conventional methods was of high quality in one instance and of lesser quality in a second when possible autofluorescence of the horse blood caused inconvenience in reading tests. Tests on 14 horses shown by parasitological means to be either infected (9) or uninfected (5) produced reactions at dilutions of 1/270 to 1/7290 for infected and at 1/10 to 1/90 for uninfected animals. The accuracy of the test was further demonstrated during investigations of 701 horses in 3 states of Australia. The 30 horses reacting at 1/270 to 1/2430 were from 33 imported to 3 different farms in Australia from a common source. Investigations of crossreactivity between B. equi and B. bovis of cattle suggested that B. bovis would not interfere with the test for B. equi, but that the reverse was possible.

Animals↗
PubMed1979

Haematological investigation of a multiple case leucosis herd.

Adult cattle in a Queensland dairy herd with a history of deaths from lymphosarcoma were sampled regularly over a 4 year period for the identification of animals with persistent lymphocytosis (PL). Twenty-one of 94 animals that were sampled at least 6 times had PL. At the initial sampling 27% of the animals had lymphocytosis. Culling of haematologically positive animals in the first 18 months of the investigation reduced this to 5.3%, but cessation of the culling programme resulted in a gradual increase in the percentage of animals with lymphocytosis. Four deaths from lymphosarcoma occurred in adult animals, but only in the first 18 months of the investigation. Two of these animals had lymphocytosis and two lymphoblastic leukaemia. The calf of one of the latter cows developed lymphoblastic leukaemia and lymphosarcoma by the time it was 6 months of age. Although histological evidence of lymphosarcoma was lacking in a number of clinically normal animals with lymphocytosis, haematological investigation identified a group of animals within the herd that may develop lymphosarcoma.

Animals↗
PubMed1979

Epidemiology and control of anaplasmosis in Australia.

Anaplasmosis occurs in those areas of northern and eastern Australia infested by the cattle tick Boophilus microplus but it has been studied intensively only in Queensland. Anaplasmosis is predominantly a disease of autumn and winter and of cattle greater than 1 year of age. The complement fixation test has been used in serological surveys of the tick-infested areas of the state. Both clinical and subclinical infections occur only in tick-infested areas and they are both more frequent in Bos taurus than in Bos indicus cattle probably due to the greater susceptibility of the former to ticks. Prevalence of infection is significantly greater in cattle exposed to heavy tick infestations than it is in cattle exposed to light tick infestations. B. microplus is considered to be the main vector with transmission being effected by transtadial and intrastadial but not transovarial means. Transtadial transmission by Rhipicephalus sanguineus has been demonstrated but attempts to demonstrate transmission by Haemaphysalis longicornis were unsuccessful. Vaccination with Anaplasma centrale is employed either as a routine preventative measure in young cattle or in the face of an outbreak. Attempts to attenuate a strain of A. marginale by adapting it to sheep were unsuccessful. Oxytetracycline and imidocarb have been used successfully to control the clinical disease.

Anaplasmosis↗
PubMed1975

Bovine melioidosis in South-Eastern Queensland.

Acute fatal infection with Pseudomonas pseudomallei caused pneumonia, placentitis and endometritis in a pregnant cow. Pneumonia was also present in the foetal lung. Mononuclear cell response with extensive karyorrhexis occurred in maternal and foetal lung and the same cellular pathology, but with diffuse distribution, was responsible for plaques on the endometrium. A more chronic disease with encapsulated caseous lesions in the lung, together with arthritis, occurred in a bull on the same property. Nutritional and physical stress caused by a flood were thought to be predisposing factors. An unusually wet summer with prolonged flooding apparently provided suitable environmental conditions for saprophytic growth of Ps. pseudomallei in an area far south of the region in which infection of animals with this organism commonly occur.

Animals↗