PubMed Health⌕ Search

Biomedical subjects

A L Parodi

Publications and source records attributed to A L Parodi.

70 records · Page 4Linked to original sources
PubMed1978

Bovine leukemia virus (BLV) specific RNA in infected cells.

BLV specific RNA sequences were detected by hybridization to the single stranded DNA copy of the viral RNA in fetal lamb kidney cells infected with bovine leukemia virus (FLK-BLV). The DNA synthesis was carried out in vitro by an endogenous reaction. It was found that uninfected lamb cells do not contain RNA sequences related to the BLV genome, whereas BLV-DNA completely annealed to FLK-BLV RNAs. RNA from FLK-BLV cells contains three species of virus specific RNA which sediment respectively at 35 S, 20--24 S and 12--4 S. In view of their EDTA-sensitive association with ribosomes, viral specific RNA sequences are viral messenger RNAs and their polarity is identical to that of the 70 S viral RNA.

Cells, Cultured↗
PubMed1978

Characterization of antibodies responsible for the inhibition of BLV induced early polycaryoxytosis.

A quantitative in vitro assay (EPI) was developed for the serological detection of bovine leukemia virus (BLV) infection in cattle. Positive sera react in inhibiting early polycaryocytosis (EP) induced by BLV. We report here experiments which demonstrate that BLV induced antibodies are responsible for this inhibition. Serum fractionation by gel filtration and affinity chromatography indicates that EP inhibiting activity is mediated by immunoglobulins of the IgG class but not by those of the IgM or other classes. Furthermore, in view of their ion-exchange chromatographic behaviour, these antibodies were attributed to the IgG1 subclass. We also ruled out the participation in the EP inhibition rection of the other compounds like polypeptides, including serum complement and interferon or DNA and RNA. These results demonstrate that EP inhibition by bovine sera is specific of BLV induced antibodies.

Animals↗
PubMed1978

Early polykaryocytosis inhibition test: evaluation of its performance in a seroepidemiological survey of bovine leukemia virus induced antibodies in cattle.

We report the results of a seroepidemiological survey, using the recently described early polykaryocytosis inhibition (EPI) assay to detect bovine leukemia virus (BLV) infection in cattle. At the herd level, there is a good correlation between epidemiological, hematological, anatomopathological data and of both the presence and titer of EP inhibiting antibodies. The EPI procedure revealed to be more sensitive than two other routine serological techniques, complement fixation and immunodiffusion. In addition, at the individual level the average EPI titers of the sera increase progressively from normal to hematologically-suspect, -- positive and finally to lymphosarcomatous animals; when the age is considered, there is a very significant increase of the amount of EP inhibiting antibodies among lymphocytotic animals, while there is only a very moderate increase of the EPI titer among hematologically normal contact animals. This suggests a loss of control of BLV expression in most lymphocytotic animals and may explain the more frequent occurrence of lymphosarcomas in this category of animals. The horizontal transmission of BLV throughout the entire life span is supported by the observation of an increase with age of the percentage of animals with EP inhibiting antibodies.

Age Factors↗
PubMed1977

Bovine leukemia virus specific antibodies among French cattle. II. Radioimmunoassay with the major structural protein (BLV p24).

A radioimmunoassay (RIA) for the major internal protein of the bovine leukemia virus (BLV p24) was established using anti-BLV p24 natural antibodies and purified 125I-labelled BLV p24. The final precipitation of the immune complexes was realized by a preparation of inactivated Staphylococcus aureau Cowan I. Sera from 363 cows belonging to (1) leukemic herds, (2) non-leukemic but BLV-exposed herds, and (3) apparently unexposed herds were studied comparatively in BLV p24 RIA, complement fixation and immunodiffusion. The BLV p24 RIA appeared much more senstive than the two other methods in the detection of positive sera. With this method 100% of the leukemic animals, excluding those with juvenile lymphosarcoma, presented very high antibody titers (greater than or equal to 10,000). Practically all cows with persistent lymphocytosis were also positive with slightly lower levels of antibodies, confirming the relationship between BLV infection and the persistent lymphycytosis. Moreover, about two-thirds of the hematologically suspect animals and one-third of the normal animals from BLV-exposed herds were found positive, whereas 100% of the sera from unexposed cows remained negative for anti-BLV p24 antibodies.

Animals↗
PubMed1977

Bovine leukemia virus specific antibodies among French cattle. I. Comparison of complement fixation and hematological tests.

Complement fixation (CF) and hematological studies were performed on 517 cows living in normal conditions in different geographical areas of France. The animals belonged to three different categories: (1) multiple or single case herds, in which lymphosarcomas had been detected in the past five years. (2) Leukemia free herds of high risk regions. (3) Leukemia free and apparently unexposed herds. Positive animals were found with both methods in the first two categories but not in the third. Persistent lymphocytosis and CF antibodies were more frequent in leukemia than in exposed but leukemia free herds. Approximately 2 times more animals were found positive by serologic than by hematologic tests. The mean geometrical titer of CF antibodies was higher in lymphocytotic than in normal animals and highest in lymphosarcomatous cows. Persistent lymphocytosis was first detected in 3-years-old animals whereas 22% of younger cows were positive in the CF test.

Animals↗
PubMed1977

Proteins of bovine leukemia virus. I. Characterization and reactions with natural antibodies.

The bovine leukemia virus (BLV) was purified from a chronically infected fetal lamb kidney cell line. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of this virus revealed the presence of eight distinguishable viral components with molecular weights ranging from 80,000 to 11,000. The major component is a non-glycosylated protein having a molecular weight of 24,000 (p24). At least three heavier polypeptides were found, one of them representing a glycoprotein (gp 60). In addition, four minor polypeptides with respective molecular weights of 19,000, 16,000, 13,000, and 11,000 were identified. In a complement fixation assay using naturally occurring antibodies of a leukemic cow, four polypeptides, which included gp 60, p35, p24, and p16, were found to be reactive.

Antibodies, Viral↗
PubMed1975

[C-type virus particles in lymphocytes cultured from cows with persistant lymphocytosis. Preliminary results on French cattle stock].

C type virus particles were shown in cultures of lymphocytes originating from cows with persistent lymphocytosis. These observations on French cattle are in complete accordance with data previously obtained in the USA. Viral replication is highly stimulated by the addition of phytohemagglutinin in the culture medium. Several morphological and biological properties, specific to the bovine virus differentiate this virus from C type viruses of other species.

Animals↗
PubMed1975

[Feline leukemogenic and sarcomatogenic viruses].

Feline Leukemia and sarcoma viruses (FeLV, FeSV) are RNA viruses, belonging to the Oncornavirus group. They possess common morphological, biochemical and immunological properties, with viruses of leukemia and sarcoma already known in others mammalian and avian species. FeLV is widely present in feline population and its transmission is by horizontal way. FeLV and FeSV are oncogenic for others species, i.e., dog and some non-human primates but as far as we know, the human receptivity is not established. A correlation between humoral antibody directed against membran new-antigens and regression of tumors induced by FeSV, led to actual investigations on vaccination.

Animals↗
PubMed1975

[Effect of ammonia treatment of peanut meal cake contaminated with A. flavus on nutritional value for the duckling].

Duckling are feeding peanut and meal detoxified or not by ammonia at the level of 25 p. 100. Control group are eating soybean meal at the same level. The raw protein content of diet is the same in each group. Experiment is carried out during four weeks, then duckling are killed. There is no significative difference between peanut meal detoxified and soybean meal relating to growth and food efficiency. Thus body weight is 775 and 764 g on duckling eating soybean meal; 764 and 827 g on duckling with peanut meal detoxified but only 472 and 452 g on birds with diet containing peanut meal not detoxified by NH3. Liver's weight is increased on these subjects. The ratio of liver weight to body weight X 100 is 5,49-4,79 and, respectively, 2,70-3,60 and 3,86-3,56 on duckling with detoxified peanut meal or controls eating soybean meal. Characteristic lesions of aflatoxicosis are developed on duckling consuming peanut meal not detoxified dosing about 285 mug/kg of Aflatoxin B1. Lesions are very slight, but present, on liver and kidney in detoxified peanut meal fed duckling. For kidney's lesions there are no differences between detoxified or not group, duckling eating detoxified peanut meal have absorbed 0,4 mug of Aflatoxin B1 during the eight first days of experiment and 8 to 10 mug during four weeks. These considerations explain light lesions observed and underlines duckling's sensitivity regarding aflatoxicosis.

Aflatoxins↗
PubMedDate not supplied

[Bovine spongiform encephalopathy: a new entity caused by a non-conventional transmissible agent].

In 1986, a new neurologic disease appeared in the Great Britain's Cattle. According to its histological lesions, this condition belongs to the group of transmissible encephalopathies known as spongiforme encephalopathies (SE). These SE are associated with no-conventional transmission agent (NCTA) or Prion. At the time of writing, over 13,000 cases of Bovine spongiforme encephalopathy (BSE) have occurred in UK. The most likely origin of this dramatic outbreak would be an oral contamination of Cattle by the feeding of sheep carcasses or of all infected with scrapie, another SE, incorporated to concentrates. Possible factors as changes (lower temperatures and reduced use of organic solvents to extract fats) in the rendering process could have preserved the very resistant Prion in these concentrates. The important lessons resulting from our present knowledge and hypothesis are there would be no species barrier to impede transmission of the NCTA through oral route. The question concerns the public health risks posed by BSE. Two related diseases of human are Kuru and Creutzfeldt-Jacob disease. At the present time, based upon epidemiological datas on scrapie, BSE is unlikely to be a major threat to humans. Nevertheless, precautionary steps to reduce a potential risk to an absolute minimum were taken by British regulations and more recently, by European directives.

Animals↗