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J Nicolet

Publications and source records attributed to J Nicolet.

At least 145 records · Page 8Linked to original sources
PubMed1987

Comparison of enzyme-linked immunosorbent assay (ELISA) and indirect hemagglutination (IHA) in experimental Mycoplasma hyopneumoniae infection of pigs.

Twenty-five hysterectomy-derived piglets were infected intratracheally at 16 days of age with a field strain of Mycoplasma hyopneumoniae. Twenty uninfected piglets constituted the control group. Clinical symptoms were noted daily and sera collected weekly. The 45 pigs were killed from 1 to 20 weeks after infection. M. hyopneumoniae induced a temperature response, coughing and pneumonia. After 10 weeks, a noticeable regression of the macroscopic lung lesions was observed. The infection was followed by an antibody response, and the antibody titers reflected the disease stages. ELISA appears to be the most sensitive procedure to detect early and late antibody production.

Animals↗
PubMed1986

Serological diagnosis of Q fever endocarditis.

The diagnosis of Q fever endocarditis cannot be made by bacterial cultures and necessitates serological identification of specific antibodies to Coxiella burnetii which stimulates mainly the production of anti-phase II antibodies during the acute disease, but primarily anti-phase I antibodies in endocarditis. Indirect microimmunofluorescence allows rapid detection of specific IgA, IgG and IgM. The results of serological analyses of 191 acute cases of Q fever were compared with those of 8 cases of Coxiella burnetii endocarditis. All sera were evaluated by complement fixation and microimmunofluorescence tests. The highest titre differences between primary Q fever and Q fever endocarditis were observed with anti-phase I IgA and IgG antibodies measured by microimmunofluorescence followed by anti-phase I antibodies measured by complement fixation tests. Antiphase I IgG and IgM titres were consistently higher than anti-phase II titres in endocarditis. The reverse is true in acute Q fever. In addition, anti-phase I IgA appeared to be diagnostic for Coxiella burnetii endocarditis. Accordingly we recommend the testing of these specific IgA, IgG, and IgM by microimmunofluorescence in cases of culture-negative endocarditis. These tests could also prove useful for following the development of Coxiella burnetii endocarditis in patients under treatment.

Antibodies, Bacterial↗
PubMed1986

Morphological variations of Haemophilus parasuis strains.

Haemophilus parasuis strains isolated from the noses of apparently healthy animals and from animals with pathological conditions were examined for the presence of a capsule, for their ability to agglutinate in acriflavine or after boiling, and for their peptide profile after polyacrylamide gel electrophoresis (PAGE). The capsule was identified by precipitation against hexadecyl trimethylammonium bromide (Cetavlon), by demonstration of iridescence, and by means of a capsule-staining method. We found a group of capsulated strains showing a rather coccobacillary morphology compared with the morphology with polymorphism, varying from rod-like to filamentous, in strains without detectable capsules. The strains of the latter group were agglutinated by acriflavine or by boiling. Soluble antigens of capsulated strains reacting with Cetavlon were thermostable and resisted proteolytic enzymes, thus suggesting the presence of an acidic polysaccharide. A few of the capsulated strains did not precipitate with Cetavlon, which indicated that their chemical composition was different. Acriflavine-positive strains belonging to a definite PAGE pattern (type II) seemed to be associated with pathological conditions more frequently than were capsulated strains which were mostly isolated from nasal cavities of apparently healthy pigs. We put forward the hypothesis that the agglutinability in acriflavine, together with the PAGE profile type II, may be associated with particular structures responsible for virulence.

Acriflavine↗
PubMed1986

Some antigenic properties of Haemophilus parasuis and a proposal for serological classification.

We propose a serological classification of Haemophilus parasuis into at least five serovars, using an agar-gel-precipitation test with extracts from autoclaved cells. Thirty-two strains were examined, and it was possible to classify 26 of them. The specific antigens were thermostable and soluble and were not affected by pronase treatment but could be extracted by phenol, suggesting a polysaccharide. This polysaccharide seemed to be identical with the capsular substance of serovars 1, 2, and 3. In the presumably uncapsulated strains of serovars 4 and 5, the specific antigen was probably located in the outer membrane. The diversity of the specific substance within the different serotypes was shown by the differences in their electrophoretic migration patterns. Other extraction procedures showed that the washing supernatant and extracts at 60 and 100 degrees C were identical with the 121 degrees C extracts for serovars 1, 2, and 3. In serovars 4 and 5, washing antigens, if present, were different from 100 and 121 degrees C extracts. Other common antigens, presumably proteinaceous antigens, were detected after extraction at 60 and 100 degrees C. The slide and tube agglutination tests allowed classification only for the capsulated strains of serovars 1, 2, and 3. The specific agglutinogens were very sensitive to incubation temperature, and the absorption test showed them to be identical with the 121 degrees C precipitinogens.

Agglutination Tests↗
PubMed1985

A chemiluminescent assay for mycoplasmas in cell cultures.

A chemiluminescent assay for the detection of mycoplasma contamination of cell cultures is described. Cells (and supernatant) derived from mycoplasma-contaminated cultures stimulate a burst of luminol-dependent chemiluminescence in cell suspensions containing phagocytic effector cell types. The assay conditions for spleen cells, human and bovine polymorphonuclear leucocytes as the responder or indicator cells have been optimized. The chemiluminescent assay can be utilized for both monolayer and suspension cell cultures and is more sensitive than colony formation on agar plates and electron microscopy. Results are obtained within 3-5 h including the time required for the preparation of the indicator cells. CL can be measured in the tritium window of standard liquid scintillation spectrometers after switching off the coincidence circuit.

Cells, Cultured↗
PubMed1985

Stimulation of immunoglobulin-containing cells and isotype-specific antibody response in experimental Mycoplasma hyopneumoniae infection in specific-pathogen-free pigs.

The development of immunoglobulin-containing cells and antigen-specific plasma cells in retropharyngeal and bronchial lymph nodes, in lung tissue, and in nasal mucous membrane was followed during an experimental infection of pigs with Mycoplasma hyopneumoniae. An enzyme-linked immunosorbent assay was used to follow stimulation of the immunoglobulin isotypes (classes) M, G, and A directed against the infectious agent in tracheobronchial secretions and systemically. A significant increase of antigen-specific plasma cells in lymph nodes and lung tissue as well as antibodies in tracheobronchial secretions was demonstrated 2 weeks after infection. This specific reaction was followed by a marked increase of immunoglobulin-containing cells in lymph nodes and lung tissue. The data are discussed in terms of autoimmune reactions in the pathogenesis of enzootic pneumonia.

Animals↗
PubMed1985

[Postoperative wound infection in the horse].

A systemic investigation of wound infection in the horse after operative treatment of large wounds reveals that the age of the wound is of critical importance. The limit for an uncomplicated healing process lies around four hours. The duration of the operation itself is of little significance, the location of the lesion on the body of the horse, however, plays a major role. The pattern of isolated bacterial organisms is discussed in relation to the duration of hospital treatment. It is concluded that a systemic antibiotic therapy is of no value and that a local antibiotic therapy is only indicated in rare instances. Such a treatment undoubtedly favours the resistance of bacteria against various chemotherapeuticals, which unfavourably influences wound healing.

Animals↗
PubMed1984

Plasmid profiles of Staphylococcus aureus causing bovine mastitis.

Plasmid profiles of Staphylococcus aureus, isolated from herds affected with chronic bovine mastitis, are heterogeneous, as shown by the study of 85 strains from 18 different farms. The strains isolated within a herd sometimes show related plasmid patterns, although even strains isolated from different quarters of the same udder may show variations in their plasmid content. Strains without antibiotic resistance are frequently free of plasmids. Therefore, the existence of mastitis Staph. aureus virulence plasmids is unlikely. Staphylococcus aureus, resistant to penicillin and streptomycin from 9 different farms show related plasmid patterns. This result confirms a geographic spread of certain mastitis Staph. aureus strains.

Animals↗
PubMed1983

[How widespread is Q fever in Switzerland?].

There are very few reports in the literature on mass seroepidemiological studies of the prevalence of Q fever antibodies. Those to be found are mostly concerned with focal epidemics of Q fever. Out of more than 2000 serum specimens from blood donors analyzed at random in Switzerland in 1982 for Q fever antibodies, 3.5% gave seropositive results (CBR titer at least 1:10). In selected population samples, e.g. forestry workers or vets, the prevalence was distinctly higher (7.6% and 25.7%). Contact with sheep and the consumption of unboiled and not commercially processed milk proved to be mutually independent risk factors. The foregoing findings indicate that the incidence of Q fever in Switzerland is higher than would appear from the number of cases reported to the Federal Health Department. They are discussed in view of the recent renewed interest in Q fever endocarditis.

Animals↗