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Biomedical subjects

M Fournier

Publications and source records attributed to M Fournier.

338 records · Page 19Linked to original sources
PubMedDate not supplied

Distribution of cells binding anti-IgE in the trachea and in the thoracic lymph nodes of ovalbumin-sensitized rats.

We investigated in the present study the distribution of anti-IgE binding cells in the trachea and in the thoracic lymph nodes of ovalbumin (OA)-sensitized rats. Sensitization of the airways was induced through a single intratracheal injection of the antigen, and was controlled by recording in vitro the antigen-induced contraction of the tracheal muscle: 12 of 15 (80%) OA-injected rats had a demonstrable status of tracheal sensitization. An immunohistochemical method was used for the localization of the anti-IgE binding cells in cryostat and in Carnoy fixed tissue sections. Virtually no cell was found to bind anti-IgE in the tracheas or in the thoracic lymph nodes from control animals. Conversely, we found in OA-sensitized rats that: 1) numerous IgE plasma cells appeared in the medullary cords of the lymph nodes (not in the trachea); 2) in tracheal sections, IgE concentrated in the cytoplasm of subepithelial mast cells and of nonciliated rounded epithelial cells (possibly the so-called globule leukocytes), but few if any mast cells of the connective tissue bound the anti-IgE conjugates.

Animals↗
PubMedDate not supplied

SO2-induced bronchopathy decreases airway sensitization with intratracheal ovalbumin in the rat.

We investigated in this study the effect of SO2-induced bronchopathy on airway sensitization to ovalbumin in the rat. Sprague-Dawley rats were immunized with a single intratracheal injection of ovalbumin (OA) 100 micrograms in 0.1 ml PBS or 0.1 ml Bordetella pertussis (BP) heat-killed vaccine (6.5 X 10(9) cells X ml-1). The rats were primed immediately after SO2 exposure (60 h, 200 ppm; group I, n = 16) and three months after exposure was achieved (group II, n = 24), then compared to a control group exposed to air (group III, n = 30). Airway sensitization was evaluated by the in vitro contractile response to antigen challenge using paired tracheal rings. Specific IgE level was determined with PCA reactions. No significant difference was found in the maximal contractile responses to carbamyl choline within and between each group. Excepted in animals of group III, OA alone was not found able to sensitize the airways. When OA was used in association with BP, sensitization of the airways occurred, but this occurrence was found to depend upon a previous SO2 exposure: 73.3% in group III, 41.7% in group II and 25% in group I were sensitized. In addition, only five animals (BP + OA injected rats of group III) displayed a PCA positive reaction. It is concluded that: 1) the concomitant intratracheal injection of BP with OA increased the occurrence of specific airway sensitization, 2) a previous chronic exposure to SO2 decreased the specific tracheal smooth muscle sensitization to intratracheal ovalbumin. This decrease persisted, although slighter, when immunization was done three months after the exposure to SO2 was stopped.

Airway Resistance↗
PubMedDate not supplied

Tracheal globule leukocytes and subepithelial mast cells: a comparative study in the rat.

We studied some morphologic, histochemical and functional characteristics of rat tracheal granulated cells. These cells are present within the epithelium (globule, leukocytes) and in the subepithelial area (subepithelial mast cells). In the latter, they are mostly concentrated in the membranous part of the mucosa. Both cell types present the main characteristics of mast cells (metachromasia and ability to bind IgE). However, they are distinct from each other in morphological and histochemical criteria and in their response to intensive corticosteroid administration. Marked differences exist between subepithelial mast cells and mast cells from the connective tissue. This raises the hypothesis of the existence of a respiratory counter part to the intestinal mucosal mast cells.

Animals↗
PubMedDate not supplied

Application of the avidin-biotin-peroxidase complex method to the light microscopic localization of the IgA in the tracheal mucosa and the thoracic lymph nodes of the rat.

Visualization of rat IgA within the tracheal mucosa and the thoracic lymph nodes was achieved using the avidin-biotin-peroxidase complex (ABC) method. This technique was compared to the indirect immunoperoxidase technique and both techniques were applied at the light microscopic level, with various fixing and embedding procedures. The ABC method was found superior to the indirect method with respect to sensitivity, to background staining and to the overall reaction time.

Animals↗
PubMedDate not supplied

[Proceedings: Pituitary thyroid axis in subacute thyroiditis (author's transl)].

We studied 10 patients with subacute thyroiditis. All had an increase in free thyroxine index, PBI, T4 and PBI/T4 ratio, an absence of thyroidal radioiodine uptake and no increase in plasma TSH after TRH injection. Exogenous TSH increased the uptake in 6/9 patients. The three patients who did not respond to TSH had higher PBI/T4 ratio than others. After treatment for one month there was either a normalization of laboratory tests either a subnormal thyroid function associated with an absence of response to TRH. All tests became normal two months later.

Humans↗
PubMedDate not supplied

Suppression of bronchoalveolar lymphocyte antibody secretion by alveolar macrophage: an in vitro study in the rabbit.

The effect of rabbit alveolar macrophage (AM) on the antibody secretion of bronchoalveolar lymphocytes was investigated in vitro, using a plaque-forming cell assay. Animals were intratracheally primed and reimmunized with 10(10) sheep red blood cells (SRBC). Free alveolar cells were obtained by lung lavage and broncho-alveolar lymphocyte-enrichment was achieved through Sephadex G-10 columns. Cell suspensions with various macrophage-to-lymphocyte ratios (AM:L from 1:25 to 3:1) were prepared using appropriate numbers of plastic adherent alveolar cells. After a 4 day in vitro co-culture of 5 X 10(6) alveolar cells (AM plus lymphocytes) with 3 X 10(6) SRBC, IgM and IgG antibody-forming cells (AFC) were counted. A significant suppressive effect (p less than 0.05) of AM on both IgM and IgG-AFC was observed when AM:L ratio was increased from 1:25 to 1:10. This effect was slightly accentuated with higher AM:L values, required viable AM, and was not affected by adding indomethacin in the culture medium. Moreover, a preliminary co-culture of AM with bronchoalveolar lymphocytes and the antigen was necessary for the expression of this suppressive effect. These data suggest that the suppressive activity of primed AM on alveolar lymphocytes may be of physiologic significance in vivo in the regulation of one of the pulmonary immune responses to airborne antigens, namely local antibody production.

Animals↗
PubMedDate not supplied

Immunologic competence of the bronchi in the rabbit: the IgA-mediated plaque-forming response to intratracheally injected sheep erythrocytes.

Immune responses to intratracheally injected sheep erythrocytes in rabbits were investigated in bronchi, thoracic lymph nodes (TLN), mesenteric lymph nodes (MLN) and spleen using an IgA-mediated haemolytic plaque-assay. The time-course appearance of specific IgA antibody forming cells (IgA-AFC) was studied in each tissue after primary and secondary immunizations. Overall low splenic and MLN responses suggest weak systemic and intestinal immunizations, respectively. Peak IgA-AFC concentrations occurred in TLN five days after priming and, in a lesser extent, three days after the booster. Conversely, the bronchial response was delayed, progressive and enhanced by the re-immunization. These results strongly suggest that bronchial-derived, IgA-precommitted cells are the major source of these specific IgA-AFC which concentrate in bronchi and that, before homing in the submucosa, they accumulate transiently in the TLN.

Animals↗
PubMedDate not supplied

Lack of reliability of the SISI procedure for determining inner ear threshold.

Ten normally hearing subjects were tested using the conductive short increment sensitivity index procedure to evaluate the 60-dB constant as used in the test described by Byers (1974). Also investigated were the effects of frequency and order of presentation on the short increment sensitivity index at high sensation levels. Test frequencies included 1, 2, 4, and 6 kHz in random order. Means of all frequencies exceeded the 60-dB constant implemented by Byers (1974). Intersubject variability was large. Frequency and order of presentation were not statistically significant factors. It was recommended that the conductive short increment sensitivity index be used with caution.

Acoustic Stimulation↗