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Biomedical subjects

J J Gardner

Publications and source records attributed to J J Gardner.

32 records · Page 2Linked to original sources
PubMed1985

A survey of ovine dermatophilosis in Western Australia.

A random sample of 200 Merino sheep owners was interviewed by telephone during April 1983 and asked questions relating to the prevalence of ovine dermatophilosis in their flocks, methods used for prevention and treatment of dermatophilosis, management strategies employed and the location and annual rainfall of each farm. The response rate was 99.5%. During the previous 12 months 62.3% of farmers had observed dermatophilosis in their flocks. The prevalence within flocks was highest in hoggets (mean 2.2%, range 0 to 75%) followed by lambs (mean 0.8%, range 0 to 25%), ewes (mean 0.6%, range 0 to 20%) and wethers (0.2%, range 0 to 20%). The mean weight of wool identified as affected by dermatophilosis was 58 kg (range 0 to 882 kg). Preventive measures were used on 57% of farms and the most common methods were changes in dipping practice (23.6%) and culling of affected sheep (21%). An average of 13.7 sheep per farm were culled for dermatophilosis and of these, 82% were sold and the remainder (18%) were killed on the farm. Antibiotics, of which most were combinations of penicillin and streptomycin were used to treat dermatophilosis on 8.5% of farms and treatments other than antibiotics were used on 10% of farms. The prevalence of dermatophilosis and its relationship to various environmental and management factors varied with the age and sex of sheep. Discriminant analysis indicated that of the factors studied, average annual rainfall, month of lambing, average fibre diameter and the month ewes were shorn were related to the prevalence of dermatophilosis in lambs.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1983

Experimental allergic neuritis-like disease in rabbits after injection with influenza vaccines mixed with gangliosides and adjuvants.

An experimental allergic neuritis-like disease was induced in rabbits 3 to 8 weeks after injection with large doses of influenza vaccines mixed with gangliosides, cholesterol, and Freund complete adjuvant. The inclusion of gangliosides was essential to induce the experimental allergic neuritis-like disease. In trials with six different lots of vaccine, both swine influenza and non-swine influenza vaccines produced by four different manufacturers induced experimental allergic neuritis-like disease in 26 of 43 inoculated rabbits.

Animals↗
PubMed1983

Radioimmunoassay of sodium cromoglycate in human plasma.

A sensitive radioimmunoassay method for sodium cromoglycate in human plasma is described. The lowest quantifiable concentration of sodium cromoglycate is 0.93 nmol/l when 0.1 ml plasma samples are analysed. Direct analysis of sodium cromoglycate concentrations in plasma samples collected up to several hours after the administration of single therapeutic doses of the compound is possible. An antiserum raised in a sheep, radioligand heterogeneously labelled with iodine-125, and a second antibody technique for the separation of bound and free radioligand are employed. The inter-assay coefficient of variation is less than 14% (n = 23). The range of the method is limited; both 0.01 and 0.1 ml volumes of plasma must be analysed to encompass the concentration range 0.93-139 nmol/l which may be encountered in plasma samples from patients and human volunteers. The method is specific for sodium cromoglycate as indicated by a low cross-reactivity of the anti-cromoglycate antiserum with a number of drugs.

Animals↗
PubMed1982

Experimental infection of rhesus monkeys with Lassa virus and a closely related arenavirus, Mozambique virus.

As a model for the pathogenesis of Lassa fever in humans, nine rhesus monkeys were inoculated with Lassa virus. Three monkeys had had a previous asymptomatic experimental infection with Mozambique virus, a closely related arenavirus; these monkeys were protected from illness and viremia and manifested only mild pathologic lesions. The other animals developed severe disease and viremia. At necropsy, hepatocellular necrosis, interstitial pneumonia, a unique pulmonary arteritis, adrenal gland necrosis, encephalitis, and uveitis were prominent pathologic lesions which correlated with the organ titers of virus. One animal infected with Lassa virus developed prolonged viremia, a typical immune response, and sudden onset of lower limb paralysis after recovery; at necropsy chronic proliferative arteritis of the spinal cord, brain, and heart was evident. Similarities and differences in the pathologic lesions in this model and Lassa fever in humans indicate that care must be taken in interpreting the results of experiments concerning immune prophylaxis, pathogenesis, and treatment in rhesus monkeys.

Animals↗
PubMed1982

Pathologic and virologic study of fatal Lassa fever in man.

Postmortem examination of 21 virologically documented cases of Lassa fever, including 6 complete autopsies, was performed as part of a field study of community-acquired Lassa fever in Sierra Leone. The most consistently observed lesions were hepatocellular, adrenal, and splenic necrosis and adrenal cytoplasmic inclusions. Neither these lesions, nor other milder and less constantly observed lesions such as myocarditis, renal tubular injury, and interstitial pneumonia, appeared severe enough to explain the cause of death in Lassa fever. The central nervous system (CNS) contained no specific lesions. Viral titrations demonstrated high viral content in liver, lung, spleen, kidney, heart, placenta, and mammary gland. Clinical laboratory data included elevation of hepatic enzymes, creatine phosphokinase (CPK), and blood urea nitrogen (BUN). Because of the paucity of pathologic lesions in spite of widely disseminated viral infection, further investigation of humoral inflammatory mechanisms is indicated.

Adult↗
PubMed1981

St Louis encephalitis. Quantitative histologic and immunofluorescent studies.

Using techniques of stereology, we measured the severity of lesions in ten cases of acute St Louis encephalitis (SLE) from the 1975 epidemic in northern Illinois. Percentage of fractional volume and numerical profile density on area (N/A) of cellular nodules and N/A of blood vessels with perivascular inflammatory cellular infiltration were significantly correlated in 17 anatomic regions of the CNS. Ranking of the severity of lesions in these regions agreed with subjective estimates of other cases of SLE. Immunofluorescent tests established the presence of SLE viral antigen in cell bodies of neurons. Our findings contribute to better understanding of the pathology of SLE in man.

Adult↗
PubMed1980

Variation in virulence for mice and rhesus monkeys among St. Louis encephalitis virus strains of different origin.

The virulence characteristics of 67 strains of St. Louis encephalitis (SLE) virus isolated from various sources in North, Middle, and South America were compared in mice and rhesus monkeys. Each virus strain was titrated in mice exactly 21 days old and virulence was expressed as the ratio of intracerebral (ic)/intraperitoneal (ip) LD50. Virus strains fell into three groups: 1) high virulence (ic/ip LD50 ratio approximately 1.0); 2) intermediate virulence (variable mortality over a wide dose range); and 3) low virulence (ic/ip LD50 less than or equal to 0.00002). Virus strains isolated during Culex pipiens and Cx. nigripalpus--borne epidemics in the eastern United States were highly virulent for mice, whereas a high proportion of the endemic virus strains isolated from Cx. tarsalis in the western United States were attenuated. Virus strains isolated from birds (the usual host for SLE virus) were highly virulent, in contrast to strains from rodents and carnivores, which were attenuated. Isolates from humans exhibited variable virulence characteristics. In experimentally-infected mice, virulence correlated with high viremia, replication in extraneural tissues, and earlier neuroinvasion. Mouse virulence correlated with clinical and histopathologic markers of pathogenicity for ic inoculated rhesus monkeys. Monkeys immunized with nonpathogenic strains by subcutaneous inoculation were partially protected against ic challenge with a virulent virus strain. The virulence classification of SLE virus strains is discussed in terms of epidemiologic correlations. This classification provides a framework for future studies on the antigenic, genetic, and biochemical bases for SLE virus strain variation.

Animals↗
PubMed1980

Experimental chronic rabies in the cat.

Two cats, inoculated with a street rabies virus strain, survived with only some progressive debility and atrophy of musculature in the injected limb for 136 weeks. They had continuously increasing titers of neutralizing antibody in serum and in cerebrospinal fluid, and terminally they had high antibody titers in the brain. Virus was isolated from two brain specimens of one cat obtained at necropsy; isolation was successful only by explant culture and inoculation of explanted tissue into mice. Virus antigen was detected in eight sites in the brain and spinal cord of the same cat by frozen-section immunofluorescence. Lesions in the central nervous system consisted of neuronal degeneration and neuronophagia, associated with the prescence of inclusion bodies and widespread inflammatory cell inflitration into brain and spinal cord parenchyma, perineuronal sites, and perivascular spaces. The inflitrates contained lymphocytes, monocytes-macrophages, and a high proportion of plasma cells. These experimental cases of chronic progressive rabies resembled more closely subacute sclerosing panecephalitis of man than the usual subacute fatal rabies encephalitis of man and other mammalian species.

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