Use of monoclonal antibodies for immunohistochemical study of bovine spleen on frozen sections.

Many monoclonal antibodies reactive with bovine leukocyte differentiation antigens are now available. Immunohistochemical staining on frozen sections using these monoclonal antibodies permits study of the functional morphology of bovine spleen. This study confirms accepted notions (B and T dependent-zones) and supplies complementary data about the repartition of CD4 and CD8 cells, gamma delta T cells, MHC (Major Histocompatibility Complex) II expression, and macrophages.

Flow cytometric analysis of bovine CD4 and CD8 lymphocytes: influence of blood sampling and processing methods.

Technical information to facilitate bovine blood treatment for optimum lymphocyte flow cytometry analysis is reported. Murine monoclonal antibodies CC8 and CC63 were used to identify phenotypes corresponding to bovine CD4 T cells and CD8 T cells. Blood samples collected in acid citrate dextrose (ACD) enhanced leucocyte subpopulation separation compared with ethylenediamine tetra-acetic acid, heparin and sodium citrate. To preserve bovine blood before immunophenotyping, samples collected in ACD may be kept at 22 degrees C or at 4 degrees C and should be analysed within 32 hours. For isolation of white blood cells, whole blood lysis was faster and gave the same results as Ficoll gradient separation 1.077 and Ficoll gradient separation 1.083. After immunophenotyping, blood could be stored at 4 degrees C if fixed with paraformaldehyde within seven days. Owing to diurnal variations, blood should be collected at a standard time of the day.

Comparative study of the action of flunixin meglumine and tolfenamic acid on prostaglandin E2 synthesis in bovine inflammatory exudate.

An acute non-immune inflammation model was used to compare the action of two non-steroidal anti-inflammatory drugs, flunixin meglumine and tolfenamic acid, on prostaglandin E2 (PGE2) synthesis in bovine inflammatory exudate. The tissue cage model used involves subcutaneous implantation of polypropylene cages and subsequent stimulation by carrageenan injection of the granulation tissue which develops within the cage. Twelve calves were randomly assigned to three groups receiving placebo, flunixin meglumine and tolfenamic acid, respectively. Inflammatory exudate was sampled 30 min after carrageenan injection and at seven subsequent time points. PGE2 levels were determined by radioimmunoassay. At each time point post-carrageenan injection, flunixin meglumine inhibited PGE2 synthesis to a greater extent than tolfenamic acid. At 4, 8, 12 and 24 h these differences were statistically significant.

Use of monoclonal antibodies for immunohistochemical study of bovine lymph nodes on frozen sections.

Many monoclonal antibodies reactive with bovine leukocyte differentiation antigens are now available. Immunohistochemical staining on frozen sections using these monoclonal antibodies permits study of the functional morphology of bovine lymph nodes. Our study confirms usually accepted notions (B and T dependent-zones) and supplies complementary data about the repartition of CD4 cells (particularly intrafollicular positive cells), gamma delta T cells, MHC II expression and dendritic leukocytes.

Responsible use of antimicrobials in veterinary medicine: perspectives in France.

In France a survey of the use of antimicrobials in veterinary medicine was set up in connection with the Committee for the Marketing Authorization of Veterinary Medicinal Products. This survey has emphasized the importance of antimicrobials in veterinary medicine and the reality of antibiotic resistance in both man and animals. Certain epidemiological data tend to demonstrate that the use of antibiotics in animals increases the risk of antibiotic resistance in man, through selection in animals of resistant pathogenic bacteria or of a non-pathogenic resistant bacteria carrying resistance plasmids. Four proposals are put forward for the control of these different risks: reserve certain antibiotics (life-saving antibiotics) for human medicine, conform to a code of good practices for antibiotic use in animals, strengthen and connect up existing networks for the epidemiosurveillance of antibiotic resistance, provide for studies on the ecological impact of antibiotics in the registration dossiers for veterinary medicinal products. These evolutive measures, based on scientific progress in microbiology, epidemiology and clinical studies should respond satisfactorily to the expectations of all concerned.

Abnormal ruminal digestion in cattle with dominantly non-digestive disorders.

Health disturbances of ruminal origin in cattle are summed up. The problems are classified in those caused by special feed (NPN for example), those caused by insufficient ruminal detoxication capacity (poisoning by nitrate or aliphatic N-derivates) and belonging to ruminal toxin production (3-methyl-indole, S-methyl-cysteine-sulfoxide, glucosinolates) and arranged in pathophysiological sense.

[Immunohistochemistry of bovine lymphoid tissue: neutralization of the non-specific reactivities of serum anti-immunoglobulins by bovine serum]. / Immunohistochimie du tissu lymphoïde des bovins: neutralisation des réactivités non spécifiques des sérums anti-immunoglobulines d'espèce par du sérum bovin.

In lymphoid tissue, the presence of high amounts of free proteins and immunoglobulins frequently leads to the observation of non-specific reactivities during immunohistochemical reactions. The types of anti-immunoglobulin sera utilized in these immunohistochemical reactions may be capable of identifying immunoglobulins secreted or harboured by the tissue cells under study, leading to non-specific marking. Incubation of these antisera with serum from the species in which the lymphoid tissue is studied neutralizes the non-specific reactivities connected with the presence of tissue immunoglobulins.

Observation on bovine congenital erythrocytic protoporphyria in the blonde d'Aquitaine breed.

Three blonde d'Aquitaine calves (one male and two females) about four months old, exhibited skin lesions just after birth, the site and nature of which suggested photosensitisation. Their porphyrin metabolism indicated a marked decrease in the activity of lymphocytic ferrochelatase, leading to a diagnosis of congenital erythrocytic protoporphyria. The associated nervous disorders of the 'recurrent epileptiform seizure' type are discussed in the light of complementary histological and biochemical tests.

A new diarrhoeic syndrome with ataxia in young Charolais calves: clinical and microbiological studies.

A new diarrhoeic syndrome was examined clinically in 19 one to two-week old Charolais calves. It differs from other digestive disorders in calves of this age in the discrete diarrhoeic signs, the absence of dehydration and the presence of signs of ataxia. The microbiological study carried out for three consecutive years in 58 sick calves and nine healthy control calves demonstrated the special role of E coli possessing virulence markers from septicaemic strains (CS31A, Col V). The clinical signs could be the result of bacteraemia with subacute E coli endotoxaemia.

An epidemiological study of winter dysentery in fifteen herds in France.

Winter dysentery is a highly contagious disease of cattle seen most often during the winter months. In the course of an epidemiological study, the management, production, hygiene and previous diseases in 15 herds were characterized by 32 variables. Each herd was then visited twice a week for 8 weeks and 8 to 10 cows were clinically examined during each visit. Winter dysentery occurred in half of the herds during the survey. All data were analysed by classical statistical methods and by multivariate analysis. Mild or severe disease provoked nasal discharge and was associated with significant economic loss. Winter dysentery outbreaks appeared to be associated with small farms in which the area available per cow is either too small or too large, the presence of coronavirus in the faeces and variations in the temperature of the stable and of the drinking water.

Hyena disease in cattle: a review.

Hyena disease was first reported in France in 1975 and since then has been recognized in many countries. It is currently regarded as a disorder of skeletal development, mainly localised in the pelvic limbs of young cattle. Some investigators consider that it is a metabolic disease but the authors believe that it may be caused by a virus. Their hypothesis, according to which bovine virus diarrhoea-mucosal disease virus is involved, is based on epidemiological, histopathological and immunological evidence.

A sequential broncho-alveolar washing in non-anaesthetized normal bovines: method and preliminary results.

The method of lung lavage under fiberoptic control allowed collection of alveolar cells in non-anaesthetized adult cows. The median section of the diaphragmatic lobe was lavaged with five consecutive aliquots of 30 ml each. Every one was analysed separately. A mean of 25.6% of instilled fluid was recovered and this is lower than amounts obtained on isolated lungs or in anaesthetized calves (about 50%). The cellular formula of 30 samples showed 83.5% of macrophages, 6.0% of lymphocytes, 9.4% of polymorphonuclear cells, 0.5% of monocytes. Cellular viability and total cell count were similar to previously published data. All results were found to be independent of the washing sequence. This simple and well tolerated technique appeared to be a useful tool for the study of defence mechanisms of deep lung.

Infectious bovine rhinotracheitis: study on the experimentally induced disease and its prevention using an inactivated, adjuvanted vaccine.

Experimentally induced IBR was studied in calves. Intranasal challenge enabled reproducible results to be obtained, both from qualitative (clinical aspect) and quantitative points of view (virus excretion, temperature); local and general immunity were also evaluated. This challenge method is useful when studying IBR vaccines. The disease was also experimentally induced by putting healthy animals into contact with diffusor calves. A single injection of inactivated vaccine in oily adjuvant already conferred good protection; it was 100% successful against the experimentally induced disease when administered two times at a 7 or 14 day interval. Immunity obtained was long-lasting and even persisted up to one year. Therefore, this vaccine is advised for vaccination in both contaminated and high risk areas. Results obtained for both safety and potency suggest that this killed vaccine should be used rather than live vaccines.