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Biomedical subjects

L E Carmichael

Publications and source records attributed to L E Carmichael.

At least 73 records · Page 4Linked to original sources
PubMed1982

Properties of cell wall antigens of virulent Brucella canis and a less mucoid variant of reduced pathogenicity.

Properties of cell wall antigenic extracts of 2 Brucella canis strains (wild type, M+; and a less mucoid variant, M-) were compared. Cell wall antigens of each strain were extracted by 2 different methods and compared with respect to their serologic, chromatographic, and surface properties. In addition, selected enzymes were used to compare antigen sensitivity to degradation. Analysis of extracted antigens was done by gel immunodiffusion and immunoelectrophoresis. Two cell wall antigens (2-R and 3-R) were present in extracts of wild type (M+) B canis that had been treated with hot (65 C) phosphate-buffered saline solution (PBSS). Three cell wall antigens (2-S, 3A-S, 3B-S) were revealed in saline extracts of the M- variant. Hot (100 C) 1% sodium deoxycholate extracted an additional antigen (1-R or 1-S) from cells (M+ or M-, respectively) which had previously been treated with hot PBSS. Certain properties of the B canis antigen extracts were examined by ion exchange chromatography, agarose gel chromatography, affinity chromatography, and enzyme degradation. Hydrophobic properties of the cell wall antigens were examined by their behavior in divalent cation, polyethylene glycol, and acid solutions. The antigens of B canis (M+) cells extracted with hot PBSS were smaller in size, had a lower net negative charge, and were more hydrophobic than those of the M- cells.

Animals↗
PubMed1981

Properties of Brucella canis surface antigens associated with colonial mucoidiness.

Rough Brucella strains B. abortus (45/20), B. ovis (1182), wild type B. canis (M+) and a less mucoid (M-) variant possessed cell wall antigens that were extracted by both sodium desoxycholate (SDC) and hot phosphate buffered saline (PBS). The acid precipitability of cell wall surface antigens extracted in SDC from all four strains suggests that these antigenic complexes may be responsible for the bacterial aggregation in broth media at acid pH and for the relatively high colonial viscosity on normal agar media (pH 6.8). The antigens of B. canis (M+) extracted in PBS were serologically related to those from the other 3 strains, but they differed in acid precipitation and hydrophobic characteristics. Differences between the properties of B. canis surface antigens and those of the other rough Brucella may explain the highly mucoid nature of the canine organism when grown on conventional (pH 6.8) media.

Antigens, Bacterial↗
PubMed1981

A modified live canine parvovirus strain with novel plaque characteristics. I. Viral attenuation and dog response.

A canine parvovirus (CPV) strain (C-780916) was found attenuated for pups at 80, but not after 51 serial passages in dog kidney cell (DKC) cultures. A variant viral population ('large plaque') emerged after prolonged cultivation in DKC cultures that may be associated with reduced native virulence. Dogs vaccinated with modified CPV developed high hemagglutination-inhibiting (HI) antibody titers within 4 days of incoluation and antibody persisted. Vaccinated animals shed small amounts of virus in the feces that spread to contact dogs. After five back-passages in dogs the modified strain was not pathogenic for pups and the plaque characteristics of the virus isolated from the feces were typical of the attenuated strain. The modified live CPV did not cause infection of the fetus when inoculated parenterally into pregnant bitches at various stages of gestation. It was not pathogenic for neonatal pups. These results suggest that a safe and effective live homologous (CPV) vaccine has been developed which should aid substantially in controlling CPV infection.

Animals↗
PubMed1980

Hemagglutination by canine parvovirus: serologic studies and diagnostic applications.

Conditions for canine parvoviral hemagglutination (HA) and hemagglutination-inhibition (HI) reactions were defined. The HA phenomena were used to differentiate canine parvovirus (CPV) from feline panleukopenia virus (FPV), mink enteritis virus (MEV), and minute virus of canines. Serologic comparisons of the CPV, FPV, and MEV by HA-HI and serum-neutralization tests indicated that CPV, FPV, and MEV were antigenically similar but were different from minute virus of canines. Diagnostic application of HA tests to fecal samples from acute cases of enteritis was discussed. Combinating HA tests with HI tests on fecal samples provided a rapid and specific diagnostic method for CPV infection. Secular seroprevalence studies indicated the emergence of CPV infeciton in the United States dog population-at-large in 1978.

Animals↗
PubMed1979

Isolation and immunisation studies of a canine parco-like virus from dogs with haemorrhagic enteritis.

A newly recognised canine parvo like virus was isolated from faeces of dogs with haemorrhagic enteritis. Cell cultures from several species were susceptible to it. Virus infected cells could be demonstrated by staining with fluorescent antibody reagents (prepared against canine virus or feline panleucopenia virus) or by haemagglutination with pig or rhesus monkey red blood cells. Inhibition of haemagglutination by specific antiserum prepared in specific-pathogen-free beagles provided a convenient method for viral identification. Experimental inoculation of specific-pathogen-free beagles resulted in elevated body temperatures and caused lymphopenia lasting one to three days. Feline panleucopenia virus vaccines protected dogs against challenge with virulent canine parvo-like virus.

Animals↗
PubMed1979

Canine viral enteritis. I. Status report on corona- and parvo-like viral enteritides.

This report attempts to provide the most recent information on salient features of two newly recognized viral enteritides of dogs. The viruses, a corona-like virus and canine parvo-like virus, are distinct but the disease manifestations in a particular outbreak often are similar. Laboratory study is therefore required. The parvoviral infection generally is more severe, with leukopenia (relative lymphopenia) a most prominent feature. Knowledge of the pathogenesis, epizootiology and the host's immune response is fragmentary at the present time, but research now in progress will doubtless expand knowledge of both diseases and of the viruses that cause them.

Animals↗
PubMed1978

Small-plaque variant of canine herpesvirus with reduced pathogenicity for newborn pups.

The plaque characteristics of 13 field isolates of canine herpesvirus were found to be similar. After 312 passages of the F-205 strain in dog kidney cell cultures incubated at 35 degrees C, the virus still was virulent for newborn pups; it also had the macroplaque morphology of the wild-type virus. However, after 20 additional passages at 30 degrees C, a microplaque (mP) variant had emerged as the predominant type. Cloned mP virus retained the small-plaque characteristic after 66 transfers at 30 degrees C. The natural history of the mP strain and some of its biological properties are reported, the most significant being its lack of pathogenicity for newborn pups.

Animals↗
PubMed1978

Canine brucellosis. Current status of methods for diagnosis.

A critical review of the performance of several methods used for the serodiagnosis of canine brucellosis is presented. It is concluded that none of the procedures commonly used is, in itself, adequate to permit a definitive diagnosis in all cases. The diagnosis is simplified when several animals in a kennel are infected; however individual cases pose a variety of problems, especially when complete clinical histories are not submitted or opportunities for infection have not been disclosed. Blood cultures are an essential part of the laboratory diagnosis of B. canis infection, but bacteremia is frequently absent in chronically infected dogs. Judgements must therefore be made on the basis of bacteriologic results in concert with a variety of serologic tests, and an evaluation of clinical signs. In some instances, laboratory diagnosis is not possible without repeated samplings. The minimal diagnostic effort should include the screening of sera by the slide agglutination test (SAT). Negative results, in the absence of clinical signs, strongly suggest absence of infection. Positive SAT results indicate that further laboratory study is required. A two-stage testing procedure of all SAT-positive serums is therefore recommended. The tube agglutination test (TAT) or the 2-mercaptoethanol-TAT (ME-TAT) are valuable complementary methods; however either of these latter procedures, in conjunction with immunodiffusion analysis, appears to provide the best chances for accurate judgements of serologic results in difficult cases.

Agglutination Tests↗
PubMed1977

Canine brucellosis: bacteriological and serological investigation of naturally infected dogs in Mexico City.

Bacteriological investigation of canine brucellosis in Mexico City revealed a high rate (11.8%) of Brucella canis infection in a sampling of 59 stray dogs. When conservative criteria were employed in the interpretation of serological test results, there was general agreement between the serological and bacteriological findings; however, some animals with localized male genital tract infections could not be judged as infected solely by serological tests. All Mexican field isolates were identified as B. canis; however, some diversity was observed as regards nitrate reduction, growth in the presence of basic fuchsine, and the degree of mucoidness. The seemingly high prevalence of B. canis infection in Mexico City dogs suggests the need for further inquiry into the possible public health significance.

Agglutination Tests↗
PubMed1977

Naturally occurring respiratory disease in a kennel caused by Bordetella bronchiseptica.

The role of Bordetella bronchiseptica as a primary pathogen in nautrally occurring respiratory disease of dogs has been in question since its original isolation in 1911. A study to determine the incidence of B. bronchiseptica in a closed breeding kennel has revealed that the frequency of such isolations is closely associated with mild respiratory disease characterized by a moist, sometimes productive, cough. Infection with B. bronchiseptica usually occurred shortly after weaning and produced illness which lasted for one to two weeks. The organisms, however, continued to be shed for two to three months, and important factor in maintaining the infection in this kennel. Adult dogs sampled at frequent intervals did not harbor B. bronchiseptica in spite of their almost constant exposure to heavily infected pups; immunity to reinfection, therefore, appeared to develop. The involvement of several known canine respiratory viral agents was excluded by virus isolation and serological techniques. It therefore was concluded that B. bronchiseptica was the primary cause of respiratory disease in this large breeding kennel.

Animals↗
PubMed1976

A serologic survey of a population of Georgia dogs for Brucella canis and an evaluation of the slide agglutination test.

In a serologic survey of stray and pet dog populations of Georgia, serums were screened for Brucella canis antibodies, using the slide agglutination test. If results were positive, B canis antibody titers were determined, using the standard tube agglutination test. The stray dogs had significantly (P less than 0.01) higher titers than did the pet dogs. The reactor rate was 58% higher for the slide agglutination test than for the tube agglutination test. The manufacturer's evaluation of the slide agglutination test was based on a comparison of the serologic results of that test with those of the tube agglutination test, using a comparative method that permitted the results to be interpreted as 99% agreement between the 2 tests. Reevaluation of the manufacturer's data by a different method indicated that the slide agglutination test is very accurate when the results are negative (99.7% specific) but less so when the results are positive (62.5% sensitive).

Agglutination Tests↗
PubMed1976

The mediator of cellular immunity. XII. Inhibition of activated T cells by Newcastle disease virus.

Newcastle disease virus (NDV) can interact in at least two ways with rat T cells. By adsorbing to circulating lymphocytes, the virus can transiently deflect the cells from lymph nodes and inflammatory exudates induced in the peritoneal cavity. T cells are affected regardless of age, state of activation, or position in the mitotic cycle. The effect is reversible and is mediated not only by infectious (I)-NDV, but also by UV-NDV which cannot achieve a complete replication cycle in eggs. But I-NDV has another lasting effect on activated T cells. It is revealed in the failure of virus-treated thoracic duct lymphocytes to transfer cellular resistance to Listeria monocytogenes, delayed-type hypersensitivity to soluble antigens of the parasite, and the permanent exclusion of labeled S-phase lymphocytes from inflammatory foci. Activated T cells are inhibited by virus multiplicites which have little if any effect upon the proliferative potential of antigen-sensitive T cells or localization of labeled small lymphocytes in lymph nodes. The underlying mechanism has not been determined; however, there are reasons for thinking that NDV has a lethal effect upon activated T cells, because the latter are permissive for virus replication.

Animals↗