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Biomedical subjects

A L Parodi

Publications and source records attributed to A L Parodi.

At least 55 records · Page 3Linked to original sources
PubMed1986

[Demonstration of the expression of bovine leukemogenic virus (BLV) in sheep lymphocytes by an immunofluorescence technic using monoclonal antibodies].

An indirect immunofluorescence (IF) test was developed to detect bovine leukemia virus (BLV) antigen expression in infected sheep lymphocytes, using monoclonal antibodies anti BLV-major envelope glycoprotein gp51. Peripheral blood lymphocytes were cultivated for 48 h in presence of phytohemagglutinin (PHA) (50 micrograms/ml), and then fixed with acetone. The cells were assayed for the IF test. All experimentally infected sheep were positive with this test.

Animals↗
PubMed1986

Immunocompetence of sheep experimentally infected with bovine leukemia virus.

The humoral and cellular immunological reactivity of sheep were studied throughout the first 32 weeks following experimental infection with bovine leukemia virus (BLV). Seroconversion of BLV-inoculated sheep occurred within 4 weeks, but infection was not transmitted to contact control sheep. Despite the persistence of the viral infection, no differences were demonstrated in leukograms, serum IgG concentrations, humoral response to immunization with an irrelevant antigen (rabbit red blood cells), phytomitogen (Concanavalin A and Pokeweek mitogen)-induced lymphocyte blastogenesis, or chemical (1-chloro, 2-4 dinitrobenzene) skin contact hypersensitivity, between BLV-infected and uninfected contact control sheep. These results demonstrate the absence of a nonspecific immunosuppressive effect of BLV and further negate the influence of a generalized immunological deficit on the development of clinical disease in BLV-infected animals.

Animals↗
PubMed1986

Septicaemic Escherichia coli and experimental infection of calves.

Three strains of Escherichia coli with a common surface antigen, 31a, capable of adhering to calf enterocytes in vitro were compared to reference strains of septicaemic E. coli (RVC 330 and vir E. coli). The surface antigen 31a was present in the RVC 330 reference strain. E. coli vir had a surface antigen which was not present in E. coli 31a or E. coli RVC 330. The RVC 330 and vir reference strains also adhered to calf enterocytes in vitro. Oral infection of calves not receiving colostrum with E. coli 31a was generally followed by septicaemia and death in less than 48 h. Post-mortem examination revealed pneumonia and oedema of the kidneys and gall bladder. Oral infection of calves receiving colostrum had no effect, but intravenous inoculation produced arthritis within 15 days. The comparison of these results with those previously described by other workers did not lead to the identification of pathognomonic characteristics, which could be clearly correlated with properties specific to E. coli 31a. It is suggested that, like ColV and vir, antigen 31a may be a virulence marker for certain strains of bovine septicaemic E. coli. Furthermore, the 31a antigen appears to be carried on a plasmid.

Animals↗
PubMed1986

[Diagnosis of enzootic bovine leukosis by the ELISA test of mixed and individual milk].

The ELISA test was applied to mixed milk from 325 cowsherds of the Landes region of France. From the 88 cowsheds giving a positive or inconclusive response, individual samples of milk were studied by the ELISA test, and individual samples of serum by the agar immunodiffusion test (1734 cows). The same procedure was carried out on 1250 animals in a sample of 49 cowsheds chosen at random from amongst the 237 cowsheds whose mixed milk gave a negative response to the ELISA test. The results confirmed the importance of the ELISA test applied to mixed milks, provided that the samples are studied several times per year, so as to minimize default errors. The study of individual milk allowed the identification of 92 to 94% of the infected animals, with a specificity of 98 to 99%. The systematic and repeated testing of mixed milks by the ELISA test should allow initial detection of infection and supervision of a satisfactory cost-efficiency report in the decontaminated cowsheds.

Animals↗
PubMed1985

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.

Animals↗
PubMed1984

Bacterio-pharmacological activity of Saccharomyces boulardii in clindamycin-induced colitis in the hamster.

The effect of S. boulardii on experimental colitis induced by the single oral administration of 1 mg/kg of clindamycin in the Syrian hamster was studied. Oral administration of S. boulardii for 13 days, starting 3 days prior to the administration of clindamycin, significantly reduced the mortality rate and inhibited the growth of C. difficile in the caecum and colon. There was a marked improvement in the sub-mucosa and mucosa which showed major inflammatory lesions when clindamycin was administered alone.

Animals↗
PubMed1983

Intratumoral BCG and Corynebacterium parvum therapy of canine mammary tumours before radical mastectomy.

In two parallel studies, bitches with mammary tumour received single intralesional injections of BCG (1 mg: 10(7) living bacteria) and Corybacterium parvum (10(9) killed bacteria) (53 bitches) or C. parvum alone (129 bitches) at the same dosage. Control groups received injections, following the same protocol, of 1 ml BCG suspension medium diluted in saline in the first study (51 bitches) or no injections at all (120 bitches in the second study). A block dissection, including mammary tumours, adjacent mammary glands, and regional lymph nodes, was performed 2 weeks later in all animals. On the basis of histologically confirmed malignant tumours, 48 bitches (25 treated by-immunotherapy and 23 controls) in the first study and 67 bitches (30 treated by immunotherapy and 37 controls) in the second study remained for postsurgical follow-up. The clinical tolerance of the treatment was generally good. No significant differences were found in cumulative survival rates between treated and control group in either studies.

Age Factors↗
PubMed1982

[Canine osteosarcoma as a model in comparative oncology].

Osteogenic sarcomas constitute 80% of all bone tumors in dogs, i.e. approximately 4% of canine tumors. Canine and human osteosarcomas have many clinical and pathological features in common. Epidemiological studies have provided interesting data: larger canine breeds are subject to excess risk of primary bone sarcoma, probably as high as thirty times the risk in small dogs. The appendicular skeleton, namely the metaphyses of long bones, is a preferential initial site of the tumor, and this involvement increases with the weight class of the animals. These data suggest that body size, weight or growth rate may act as factors of bone sarcoma development. Therapeutic trials on canine osteosarcoma are ongoing and could be used as models for the human counterpart.

Animals↗
PubMed1980

Spontaneous immune response of bovine leukemia-virus-infected cattle against five different viral proteins.

The sera from cattle exposed to bovine leukemia virus (BLV) have been studied by the radioimmunoprecipitation assay (RIPA) of disrupted virus proteins. All sera of animals with the adult form of lymphosarcoma precipitated four different viral proteins: gp51, gp35, p24 and p12. In contrast, the sera of five animals with the juvenile or thymic forms of bovine lymphosarcoma were completely devoid of precipitating activity against BLV proteins, confirming the absence of relationship between these rare malignant diseases and BLV infection. The sera of non-leukemic cattle from areas of high risk of exposure to BLV were either negative or positive to a lower degree than the sera of lymphosarcomatous cows. When positive they precipitated gp51, p24 and p12. Only one serum precipitated gp35. The difference was probably quantitative, the sera of leukemic animals having higher levels of precipitating activity against all the viral proteins. The anti-gp51 reactivity was in most cases the strongest, whatever the origin of the serum. In the rare sera which were positive in the classical anti-gp51 radioimmunoassay (RIA) but negative in the anti-p24 RIA, an anti-p24 activity was, however, detected by the RIPA. These results suggest that BLV-infected cows regularly produce antibodies reacting with four different viral proteins including minor viral components. In three cases with no other special features a low level of activity was detected against a fifth component: p15. There was no apparent correlation, however, between the antibody response and an hypothetical protection against BLV-induced disease.

Absorption↗
PubMed1980

Bovine leukemia virus-specific antibodies in French cattle. III. Prevalence of the BLV-gp 51 radioimmunoassay for the detection of BLV-infected animals.

The control of the spread of BLV infection among cattle requires very sensitive methods of detection. The BLV-gp51 radioimmunoassay presents great advantages over the other serological methods, including the BLV-p24 radioimmunoassay. This is clear from studies of normal animals from the high-leukemia-incidence region which show that anti-gp51 antibodies reach higher titers than anti-p24 or may even exist alone. Moreover, a sequential survey reveals that the anti-gp antibodies appear earlier. On the other hand, it was not possible to detect a viral antigen expression in the tissues of the infected animals.

Animals↗
PubMed1978

Immunological nature of the inhibition of BLV-induced early polykaryocytosis by bovine sera.

A quantitative in vitro assay (EPI) was developed for the serological detection of bovine leukemia virus (BLV) infection in cattle. Positive sera inhibit early polykaryocytosis (EP) induced by BLV. We report herein experiments which demonstrate that BLV-induced antibodies are responsible for this inhibition. Serum fractionation by gel filtration and affinity chromatography indicate that EP-inhibiting activity is mediated only by immunoglobulins of the IgG class. Furthermore, on the basis of their ion-exchange chromatographic behaviour, these antibodies were classified as IgG1. We also ruled out the participation in the EP inhibition reaction of the other compounds such as polypeptides, including serum complement and interferon or DNA and RNA. These results demonstrate that EP inhibition by bovine sera is specific to BLV-induced antibodies.

Animals↗