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Biomedical subjects

B Perrin

Publications and source records attributed to B Perrin.

At least 37 records · Page 2Linked to original sources
PubMed1994

In vivo leukocyte tropism of bovine leukemia virus in sheep and cattle.

Bovine leukemia virus (BLV), an oncovirus related to human T-cell leukemia virus type I, causes a B-cell lymphoproliferative syndrome in cattle, leading to an inversion of the T-cell/B-cell ratio and, more rarely, to a B-cell lymphosarcoma. Sheep are highly sensitive to BLV experimental infection and develop B-cell pathologies similar to those in cattle in 90% of the cases. BLV tropism for B cells has been well documented, but the infection of other cell populations may also be involved in the BLV-induced lymphoproliferative syndrome. We thus looked for BLV provirus in other leukocyte populations in sheep and cattle by using PCR. We found that while B cells harbor the highest proviral load, CD8+ T cells, monocytes, and granulocytes, but not CD4+ T cells, also bear BLV provirus. As previously described, we found that persistent lymphocytosis in cows is characterized by an expansion of the CD5+ B-cell subpopulation but we did not confirm this observation in sheep in which the expanded B-cell population expressed the CD11b marker. Nevertheless, BLV could be detected both in bovine CD5+ and CD5- B cells and in sheep CD11b+ and CD11b- B cells, indicating that the restricted BLV tropism for a specific B-cell subpopulation cannot explain its expansion encountered in BLV infection. Altogether, this work shows that BLV tropism in leukocytes is wider than previously thought. These results lead the way to further studies of cellular interactions among B cells and other leukocytes that may intervene in the development of the lymphoproliferative syndrome induced by BLV infection.

Animals↗
PubMed1994

Selection of European Union standard reference sera for use in the serological diagnosis of infectious bovine rhinotracheitis.

A study, consisting of three trials, was undertaken in order to find standard reference sera for use in serological diagnostic procedures for infectious bovine rhinotracheitis (IBR) in the European Union (EU). A total of forty-nine laboratories participated in the trials, in which panels of positive, weak positive, and negative candidate sera were tested blind by neutralisation, indirect and blocking enzyme-linked immunosorbent assay, indirect immunofluorescence and passive haemagglutination. A serum which scored positive in all tests in all laboratories was selected as a strong positive standard serum. The chosen negative standard serum gave negative results in virtually all tests. A 1/36 dilution of a positive serum was chosen as the weak positive standard serum and only very sensitive techniques were able to score it positive. Three EU reference sera are now available for the standardisation of serological tests for IBR.

Animals↗
PubMed1994

[Effect of an inhaled beta-2-adrenergic agent administered at the time of delayed bronchial reactions to occupational agents].

We previously showed in a retrospective study that the acute response to an inhaled beta-2-adrenergic agent is marked in late asthmatic reactions (J Allergy Clin Immunology 1990;85:834). In a double-blind prospective study, we assessed the magnitude and duration of the effect of inhaled salbutamol (200 micrograms) compared to a placebo in 22 subjects who experienced late asthmatic reactions (sustained fall in FEV 1 > or = 20%) after specific inhalation challenges in the laboratory with various occupational agents (isocyanates in 9 subjects). Before salbutamol was administered, the % in FEV1 over the pre-challenge values did not differ between the placebo (31 +/- 8%, n = 12) and the active (28 +/- 6%, n = 10) groups. The % recovery in FEV1 over the pre-bronchodilator value was 9 +/- 11% in the placebo group and 28 +/- 11% in the active group (t = 4.0, p < 0.001). The % recovery in FEV1 assessed in comparison with pre-challenge values was up to 80 +/- 17% in the placebo group and up to 95 +/- 6% in the active group (t = 2.85, p < 0.01). The 10 subjects on active medication had FEV1 values > or = 80% of the pre-challenge value one hour after inhaling salbutamol. The pattern of diminution in the bronchodilator effect was similar in the eight subjects with occupational asthma on active medication who remained for more than one hour as compared to a control group of asthmatic subjects paired for the degree of baseline airway obstruction. These data show that late asthmatic reactions are satisfactorily reversed with inhaled bronchodilator and that the duration of the effect is as satisfactory for subjects with occupational asthma as it is for asthmatic subjects.

Administration, Inhalation↗
PubMed1993

A European comparative study of serological methods for the diagnosis of infectious bovine rhinotracheitis.

A comparison is made of serological diagnostic procedures used for infectious bovine rhinotracheitis in the European Community. A panel of 65 sera, including positive, doubtful, negative and diluted samples was dispatched to nine different European laboratories and tested by neutralisation, enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence and passive haemagglutination, according to the methods used in each laboratory. The results showed good agreement between the various tests for positive and negative sera. However, considerable variability between tests was noted in the "doubtful" category of sera. The highest test sensitivity, as judged by the detection limit for samples serially diluted in negative serum, was found with the blocking ELISAs. A need was identified for international standard reference sera to be made available.

Animals↗
PubMed1992

Occupational asthma: validity of monitoring of peak expiratory flow rates and non-allergic bronchial responsiveness as compared to specific inhalation challenge.

The sensitivity and specificity of monitoring peak expiratory flow rates (PEFR) and bronchial responsiveness to the provocative concentration of histamine or methacholine (PC20) has been determined as compared to specific inhalation challenges in the diagnosis of occupational asthma. A prospective study of 61 subjects referred for occupational asthma to various agents was performed. PEFR was assessed every 2 h during a period away from work for at least 2 weeks. The period at work was 2 weeks, or less if there was increased symptomatology or marked changes in PEFR. At least one PC20 assessment was obtained at work and away from work. Graphs of PEFR and PC20 values were interpreted in blind fashion by three experienced readers. There was complete agreement among the three in 54 out of 61 instances (78%). Twenty five out of 61 subjects (41%) had positive specific inhalation challenges. The best index for comparing results of PEFR with specific inhalation challenges was the visual analysis of PEFR with sensitivity and specificity of 81% and 74%. All of the numerical indices were significantly less satisfactory. We conclude that visual analysis of PEFR is an interesting tool for investigating occupational asthma, although sensitivity and specificity values do not seem satisfactory enough to warrant using it alone.

Adult↗
PubMed1991

Reassessment of the temporal patterns of bronchial obstruction after exposure to occupational sensitizing agents.

Typical asthmatic reactions after exposure to common or occupational allergens have been classified as isolated immediate, early late, late, and dual (Pepys and Hutchcroft, 1975). Atypical reactions can also occur, but their temporal behavior and frequency are unknown. We analyzed 69 bronchospastic reactions after exposure to three types of occupational sensitizers in the laboratory: isocyanates, western red cedar, and IgE sensitizing agents. Graphs of the reactions were presented to three observers in a blind, randomized way. Reactions were defined as follows: (1) typical patterns, that is, isolated immediate, early late, late, and dual, as put forward by Pepys and Hutchcroft, and (2) atypical patterns including progressive (onset, during, or minutes after exposure, progressing to a maximum reaction 5 to 6 hours later) and square waved (similar to a dual reaction but with only partial recovery [less than 10%] between the immediate and late falls in FEV1). Some curves were also analyzed by polynomial regression. The three observers agreed in 59/69 cases (86%), and a consensus was reached after discussion for the remaining subjects. Fifteen of 63 (22%) reactions were atypical. IgE-mediated reactions and reactions to red cedar were, respectively, mainly of the immediate and late types. The distribution of reactions to isocyanates, however, was significantly different (chi-square, 6.1; p = 0.01), the "progressive" pattern occurring in 7/23 instances (30%). There was a satisfactory concordance between visual assessment and polynomial fit analysis in distinguishing dual from square-waved reactions. We conclude that isocyanates frequently cause atypical progressive bronchospastic reactions that are rarely observed after exposure to IgE agents and western red cedar.

Adult↗
PubMed1991

Identification of ruminant mycoplasmas by dot immunobinding on membrane filtration (MF dot).

A simple method of species identification of ruminant mycoplasmas by dot immunobinding (MF dot) is described. Mycoplasmas from broth cultures were directly trapped onto the surface of low protein-binding affinity membranes by vacuum filtration. Specific polyclonal anti-mycoplasma sera were then applied. Mycoplasma-antibody complexes were then revealed by an enzyme conjugated anti-immunoglobulin. A positive reaction was indicated by the development of a color reaction when substrate was added. The method was tested on 22 type-strains representative of species, subspecies, types or yet unnamed serogroups of mycoplasmas isolated from ruminants. MF dot presented a specificity close to that which could be expected from the reference serological tests. The advantages of the MF dot over the other tests are utility, rapidity, ready standardization and it allows many samples to be treated simultaneously.

Animals↗
PubMed1991

Is the clinical history a satisfactory means of diagnosing occupational asthma?

In some countries a diagnosis of occupational asthma for medicolegal purposes is made when a questionnaire is suggestive and the individual is exposed to a product known to be a sensitizer. The value of an open questionnaire administered by physicians with experience in occupational asthma is unknown, however. We prospectively assessed all subjects (162) referred to our clinic because their physicians thought their asthma might be work related. The medical questionnaire included questions about the nature of the symptoms (dyspnea, wheezing, cough, and chest tightness) and the timing (worse at work or after a shift at work or improved during weekends or holidays). An initial clinical assessment was set by the physician on a scale that ranged from highly probable to probable, uncertain, unlikely, or absent. Subjects then underwent objective assessment with specific inhalation challenges (n = 72), serial monitoring of peak expiratory flow rates for periods at work and away from work (n = 29), or both (n = 61), to confirm or rule out the diagnosis of occupational asthma. A total of 75 subjects (46%) were shown to have occupational asthma. Symptoms alone (type and timing) did not provide a satisfactory differentiation between those subjects with and those without occupational asthma. For example, 66 of 75 (88%) subjects with occupational asthma said that their symptoms improved during holidays, but 66 of 87 (76%) subjects without occupational asthma experienced a similar improvement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Occupational asthma in a pharmaceutical worker exposed to hydralazine.

A pharmaceutical worker developed asthma when exposed to hydralazine, an antihypertensive drug. The diagnosis of occupational asthma was supported by specific inhalation challenges, which produced a late asthmatic reaction and an increase in bronchial responsiveness. No evidence of an IgE or an IgG dependent mechanism could be found.

Adult↗
PubMed1989

[Use of nonradioactive probes to detect the gene for 3-aminoside-acetyltransferase type IV in strains of Escherichia coli and Salmonella spp].

Forty-three isolates of Escherichia coli, Salmonella dublin and S. thyphimurium of animal origin were studied by colony hybridization using an intragenic probe specific for the gene encoding 3-aminoglycoside acetyltransferase type IV, which confers resistance to apramycin and gentamicin. Non-radioactive biotinylated and sulphonated DNA probes were used. No false-positive results were found and the positive results obtained were in agreement with those previously revealed with radioactive probes.

Acetyltransferases↗