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Biomedical subjects

B Arnoux

Publications and source records attributed to B Arnoux.

72 records · Page 4Linked to original sources
PubMed1981

Bronchoconstriction induced by intratracheal administration of platelet-activating factor (PAF-acether) in baboons.

Intratracheal administration of PAF-acether (60 microgram.kg-1) was performed in six premedicated, curarized and mechanically ventilated baboons. Whereas intratracheal administration of an equal amount of solvent (200 microliter of 80 degrees alcohol in 2 ml of saline) caused no measurable changes in lung mechanics, administration of PAF-acether caused an almost immediate bronchoconstriction that was spontaneously reversible within about 30 min. The concomitant fall in platelet count in peripheral blood and reduction of perfusion of ventilated lung territories estimated from the alveolar-arterial difference in CO2 tension provide circumstantial evidence that PAF-acether also caused aggregation of platelets in the lung microcirculation. In keeping with the release of PAF-acether by human alveolar macrophages, our findings suggest that this mediator may play a role in human asthma.

Airway Resistance↗
PubMed1980

Release of platelet-activating factor (PAF-acether) from alveolar macrophages by the calcium ionophore A23187 and phagocytosis.

Platelet-activating factor (PAF-acether) was recovered from rabbit, rat and human alveolar macrophages stimulated with the Ca++ ionophore A23187. PAF-acether release was also obtained from rat and rabbit macrophages in the presence of zymosan, but not from human alveolar preparations in spite of the phagocytic activity exhibited by the latter cells. Observed releases were active, Ca++ dependent, and plateaued at 45 min. No PAF-acether was released from lungs washed out of their macrophages, another argument against the mastocyte origin of this mediator. Given the potent bronchoconstrictive activity of PAF-acether, its release from alveolar macrophages may provide an alternative explanation for non IgE-dependent asthmas and the implication of platelets in pulmonary diseases.

Animals↗
PubMed1979

The structure of amoorastatone and the cytotoxic limonoid 12-hydroxyamoorastatin.

2 new limonoid-type terpenes have been isolated from an aqueous extract of seeds produced by the Eastern Himalayan (India) plant Aphanamixis grandifolia B1. By interpreting principally mass spectral and nuclear magnetic resonance data, the structures of 12-hydroxyamoorastatin (2b) and amoorastatone (3) were elucidated. Unequivocal evidence for the 12-hydroxyamoorastatin structural assignment was obtained by chemical conversion to sendanin (4). Amoorastatin derivative 2b was found to significantly inhibit growth of the murine P388 lymphocytic leukemia cell lines but amoorastatone in the same system was inactive. In a comparative biological study, sendanin (4) and anthothecol (7) were also found significantly to inhibit growth of the P388 cell line, while rohitukin (8) and limonin (9) were found to be inactive.

Animals↗
PubMed1977

Presence of soluble SLA histocompatibility antigen in pig plasma.

The major histocompatibility antigens of the pigs (SLA 1 and SLA 15) were solubilized by papain and then iodinated according to Greenwood's chloramine T method. These antigen preparations were used in radioimmunoassays for the detection of soluble inhibitors in pig plasma. Specific soluble substances were demonstrated in addition to a certain amount of cross-reactivity with other so far unidentified antigens.

Animals↗
PubMedDate not supplied

Elevated levels of paf-acether in blood of patients with type 1 diabetes mellitus.

Infusion of paf-acether (paf, first described as platelet-activating factor) into animals stimulates glycogenolysis and lipolysis and decreases insulin levels. This study reports a 50-fold increase in blood levels of paf in patients with Type 1 insulin-dependent diabetes mellitus without micro or macrovascular complications (1.07 +/- 0.42 ng/ml, n = 10) as compared with healthy volunteers (0.04 +/- 0.02 ng/ml, n = 9). By contrast, paf is not statistically elevated (p greater than 0.05) in patients with Type 2 non-insulin-dependent, diabetes mellitus with lipid abnormalities and micro or macrovascular complications (0.32 +/- 0.18 ng/ml, n = 9). In the three groups same levels of paf precursors and acetylhydrolase activity (the enzyme which inactivates paf) were noted suggesting an increase in paf biosynthesis by Type 1 diabetic patients. Elevated paf levels could perpetuate hyperglycaemia and tend to promote or accentuate micro or macrovascular complications. This study adds another biological difference between Type 1 and Type 2 diabetes.

Adult↗
PubMedDate not supplied

[Kinetics of pulmonary defense in deep lung (author's transl)].

The association of different experimental methods using radioactive particulate aerosols with bronchial washing and morphometric techniques reveals the importance of alveolar macrophages in antibacterial defense and the interest of their quantitative evaluation. The study of the kinetics of pulmonary phagocytic systems has shown a "capillary compartment", which consists of a reserve of monocytes which are temporarily present in the lung and in transit through it. This reserve represents 4.6% (sigma=1.4) of the cells from deep in the lung and is much larger than the systemic monocytic pool. 0.5% of these monocytes are in a phase of DNA synthesis. This capillary compartment must be clearly separated from interstitial phagocytes, the number of which is insignificant under physiological conditions. The phagocytic relay by polynuclear elements appears during bacterial aggression and is interdependent with macrophagic population. The particularities of the immune defenses of the distal parts of the lung are stressed especially in comparison with systemic defenses.

Adenosine Diphosphate↗
PubMedDate not supplied

Antigenic release of paf-acether and beta-glucuronidase from alveolar macrophages of asthmatics.

Alveolar macrophages (AM) from control (n = 12) and atopic patients (n = 19, 12 without treatment, 4 treated with theophylline and 3 with theophylline and corticosteroid) were compared for their capacity to release mediators. AM were purified by 2 h adherence and challenged with either ubiquitous allergen, specific sensitizing allergens, anti-IgG or anti-IgE serum. The release of paf-acether, lyso paf-acether and beta-glucuronidase was measured. Paf-acether and its lyso derivative were assayed on washed rabbit platelets. Enzyme and mediator releases were obtained after specific allergenic or anti-IgE serum challenge of AM from untreated atopic patients. No release of paf-acether was detected from AM, from control or treated atopic patients after in vitro immunological challenge, whereas that of lyso paf-acether was greatly reduced in both treated groups. Release was obtained by immunological challenge of AM from control patients after passive sensitization with atopic serum. The release of mediators with bronchoconstriction activity by AM could represent an alternative causal pathway in human asthma.

Adult↗