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Biomedical subjects

E Fournier

Publications and source records attributed to E Fournier.

At least 91 records · Page 5Linked to original sources
PubMed1985

[Demonstration of specific platelet function anomaly in asthma induced by aspirin: diagnostic consequences].

Aspirin-sensitive asthma is a common and severe disorder characterized by asthmatic attacks after oral ingestion of cyclooxygenase inhibiting drugs. Yet its pathophysiology remains unknown, and no specific in vitro abnormality, neither humoral nor cellular, has been detected in these patients. We have recently described a new model of platelet activation--IgE-dependent platelet activation--expressed by the release of cytocidal mediators and oxygen metabolites. We have now investigated whether cyclooxygenase inhibitors induce a similar response in platelets from aspirin-sensitive asthmatics in vitro. Aspirin or indomethacin strikingly activated platelets from 12 aspirin-sensitive asthmatics to the same extent as IgE-dependent stimuli, but had no effect on platelets from 18 controls (p less than 0.0001). Sodium salicylate, which does not inhibit cyclooxygenase, did not trigger platelets from aspirin-sensitive asthmatics. Preincubation with sodium salicylate or prostaglandin endoperoxides (PGH2), selectively prevented further platelet activation by aspirin or indomethacin (90% inhibition), suggesting that this abnormal platelet activation is the consequence of cyclooxygenase inhibition. This represents the first identification of a specific abnormal cellular response in aspirin-sensitive asthma, provides the basis for an in vitro diagnostic test of the disease, and for new insights on its pathogenesis and its prevention.

Aspirin↗
PubMed1984

Electrophysiological properties of dentate granule cells in mouse hippocampal slices maintained in vitro.

Intracellular recordings were obtained from granule cells of the dentate gyrus in mouse hippocampal slices maintained in vitro. All the spikes observed in standard Krebs solution had a short duration and were tetrodotoxin (TTX)-sensitive. When elicited by synaptic activation or by direct electrical stimulation of the cells, these fast sodium spikes were followed by a brief spike afterhyperpolarization. In contrast, antidromic spikes elicited by electrical stimulation of the hilum as well as spikes arising at the end of hyperpolarizing current pulses passed through the recording microelectrode were followed by depolarizing afterpotentials (DAPs). These DAPs were reversed into brief spike afterhyperpolarizations by depolarization of the cells. After substitution of calcium (Ca) by barium (Ba) or after introduction of tetraethylammonium (TEA) in the bath, the fast spike repolarization became slower and the brief spike afterhyperpolarizations were abolished, suggesting that they involved fast K conductances. Slow spikes and long-lasting depolarizations were also elicited in granule cells in the presence of Ba or TEA. Since these slow events were left unaffected by TTX and were selectively abolished by the Ca channel blockers cobalt or cadmium, they are likely to be mediated by voltage-dependent Ca conductances, unmasked by the reduction of the fast K conductances.

Animals↗
PubMed1984

Electrophysiological properties of in vitro hippocampal pyramidal cells from normal and staggerer mutant mice.

Electrophysiological properties of intracellularly recorded CA1 pyramidal cells from normal and staggerer mice were compared by using hippocampal slices maintained in vitro. In staggerer mice, the passive membrane properties of these neurons as well as their synaptic potentials elicited by stratum radiatum stimulation were very similar to those observed in normal mice. In control and mutant mice and in standard Krebs solution, CA1 pyramidal cells mainly fired tetrodoxin (TTX)-sensitive fast spikes but could also generate slow spikes. In both groups, replacement of calcium (Ca) by barium (Ba) or introduction of TEA in the bathing medium prolonged the repolarization of the fast spikes and suppressed the brief spike afterhyperpolarization which normally followed them, thus suggesting that both events involve fast potassium conductances. Furthermore, in both groups of animals, TEA and Ba enhanced the slow spikes and induced the appearance of prolonged depolarizations. These slow events were TTX-resistant and were abolished by the Ca channel blockers cadmium or cobalt, thus suggesting that they are Ca-dependent. On the whole, the present results indicate that the staggerer mutation which yields marked abnormalities in the bioelectrical properties of cerebellar Purkinje cells has no such effect on CA1 pyramidal cells.

Animals↗
PubMed1984

A re-evaluation of the pattern of group I fibre projections in the human lower limb on using randomly alternated stimulations.

Changes in amplitude of soleus, quadriceps and biceps femoris monosynaptic reflexes were studied when preceded by conditioning stimulations applied to group I fibres from different muscles of the human lower limb. Control test reflexes and conditioned reflexes were alternated either regularly or randomly. For the most part, the same qualitative pattern of group I fibre projections was found with both modes of alternation, but the amount of facilitation or inhibition induced by group I fibre stimulation was significantly smaller with the random mode. This may be due to an underestimation of randomly-induced effects and/or an overestimation of regularly-induced effects. Because this overestimation can lead to artefactual results, regular mode of alternation should be avoided.

Electric Stimulation↗
PubMed1984

Changes in reciprocal Ia inhibition from wrist extensors to wrist flexors during voluntary movement in man.

Transmission in the Ia inhibitory pathway from wrist extensor muscles onto flexor MNs was studied at various times after the onset of voluntary wrist extension or flexion. At the very onset of wrist movements Ia inhibition was not changed, as compared to at rest, whereas later it progressively increased during wrist extension and decreased during wrist flexion. These results are discussed in relation to the different inputs converging onto Ia interneurones and it is suggested that their inhibition by Renshaw cells might be responsible for the results found at the onset of contraction.

Anterior Horn Cells↗
PubMed1984

Effect of excitatory amino acids on Purkinje cell dendrites in cerebellar slices from normal and staggerer mice.

The sensitivity of Purkinje cells to short pulse applications of L-aspartate, L-glutamate and related derivatives in their dendritic fields was tested in normal and staggerer mutant mice using cerebellar slices maintained in vitro. In normal mice, the response of Purkinje cells to L-aspartate and L-glutamate consisted of a transient and dose-dependent increase of their firing of simple spikes. The potency of L-aspartate in exciting Purkinje cells was lower than that of L-glutamate when the two drugs were released from adjacent barrels of the same iontophoretic electrode. Quisqualate was an even more potent excitant of these cells than L-aspartate and L-glutamate, whereas N-methyl-DL-aspartate had little or no effect. In staggerer mutant mice, the sensitivity of Purkinje cells to L-aspartate, L-glutamate and quisqualate was not significantly altered. On the contrary, N-methyl-DL-aspartate had a much stronger potency than normal in exciting Purkinje cells although this was still smaller than that of the other agonists tested. These results suggest that the sensitivity of Purkinje cells to L-aspartate and L-glutamate, i.e. the putative neurotransmitters of the climbing and parallel fibers respectively, remains largely normal in staggerer mice. In contrast, in the mutant, N-methyl-D-aspartate receptors are likely to be much more developed than normal.

Amino Acids↗
PubMed1984

[Systemic manifestations of angiitis with asthma and hypereosinophilia. Study of 10 cases].

We report 10 cases of systemic manifestations of angiitis with asthma and hypereosinophilia, some of which had the pathologic features of an allergic granulomatous angiitis of Churg and Strauss. We compare these 10 cases with 109 observations previously reported in the literature from which they differ by a high incidence of digestive tract involvement and by a near constant increase of total plasma immunoglobulin E concentration during the evolutive phases of vasculitis. Broncho-alveolar lavage had been performed in 3 patients, showing pulmonary hypereosinophilia. We discuss the clinical, biological and pathogenic features which differentiate this syndrome, particularly from periarteritis nodosa.

Adult↗
PubMed1983

Descending control of reflex pathways in the production of voluntary isolated movements in man.

Transmission in Ib inhibitory spinal pathways from a contracting muscle was studied during a selective voluntary contraction in man. Whereas Ib inhibition to those motoneurons (MNs) responsible for the contraction was depressed, Ib inhibition to those synergistic MNs not directly involved in the contraction was increased. This differential control, supraspinal in origin, helps limit activation to the former MNs and could be important in ensuring the selectivity of skilled movements.

Adult↗
PubMed1983

Stimulation of alveolar macrophages in asthmatic patients after local provocation test.

Dermatophagoîdes pteronyssinus allergen was instilled into the alveolar space of 7 allergic asthmatic patients during bronchoalveolar lavage. beta-glucuronidase concentration in the bronchoalveolar fluid from the challenged lung became significantly higher than that in the opposite control lung (3.90 +/- 1.88 nmol/h versus 0.86 +/- 0.55). The intracellular level of beta-glucuronidase in the alveolar macrophages in the challenged lung was 40.3% lower than that in the control lung. In 3 controls intracellular concentrations of beta-glucuronidase were similar before and after allergenic challenge and no enzyme activity could be detected in bronchoalveolar lavage fluid. These results suggest that alveolar instillation of an allergen in asthmatic patients rapidly stimulates alveolar macrophages, which may be involved in immediate hypersensitivity reactions in asthma.

Adolescent↗
PubMed1983

Poisoning with Veratrum-containing sneezing powders.

1 Nine cases of accidental poisoning of children with sneezing powder are reported. Symptoms, besides sneezing, included gastrointestinal disturbances and syncope, whilst examination demonstrated bradycardia and hypotension. 2 The powder, as supplied, carried no information on its constituents but Veratrum alkaloids were identified on analysis. The signs and symptoms observed were compatible with poisoning from these compounds. 3 As a result of these observations, it was possible to trace the manufacturers and a change was made to a safer formulation. This example emphasises the value of toxic vigilance by Poison Control Centres.

Adolescent↗
PubMed1983

[Chronic eosinophilic pneumonia. Apropos of 2 cases].

Pathologic findings in two patients with no previous history of atopic affections were apical pulmonary infiltration, a marked general syndrome with altered general state and hyperthermia, a productive cough, and a circulating eosinophilia. Clinical manifestations and the particular radiographic images of homogeneous condensation of the two apices in the form of "helmet crests", together with the typical course during corticoid treatment and histopathologic findings in one case, established a diagnosis of chronic eosinophil pneumonia. The principal characteristics of this affection, as exemplified by these two cases, are analyzed.

Adrenal Cortex Hormones↗
PubMed1983

[Bronchopulmonary pathology with hypereosinophilia of fungal origin (excluding allergic bronchopulmonary aspergillosis)].

Five cases of eosinophil lung are reported in which the fungus responsible for the affection was not Aspergillus. Documented data include reports on 19 similar cases with a clinical picture suggestive of allergic bronchopulmonary aspergillosis but with negative tests for Aspergillus. The various fungal species isolated included Candida albicans, Penicillium, Geotrichum candidum, Stemphylium lanuginosum, Culvularia lunata, and Drechsleria hawaïensis. Diagnostic criteria are discussed, with particular emphasis on the importance of the inhalation provocation test, as well as possible efficacy of antifungal treatment.

Adult↗
PubMed1983

[Secondarily infected pneumatocele, eosinophilia and excess production of IgE manifesting as Buckley's syndrome in an adult].

The hyper IgE syndrome develops in childhood and leads to repeated infectious episodes, usually of staphylococcus aureus origin and affecting mainly the skin and pulmonary parenchyma. It may be associated with a predominantly facial atypical dermatitis and more rarely with allergic manifestations. Biological tests show mainly an eosinophilia and a hypergammaglobulinemia E alone without modifications in other immunoglobulin types. Disorders of neutrophil and monocyte chemotaxis are inconstant findings. The initial mechanism of the affection appears related to a deficit in suppressive T function selectively acting on the IgE isotype.

Adult↗
PubMed1983

[Local cellular response to stress of the lower lung].

The cell populations in the alveoli are exposed to the environment and react differently to each type of challenge (mineral particles, toxic gases, infections, antigenic substances. . .). Amongst the best studied of these irritant factors is tobacco smoke which in the long term leads to a number of changes both in the distribution of alveolar cells and also their function and morphology. Amongst acute and sub-acute pathogens, bacterial infections produce a rapid poly-morpho-nuclear neutrophilia and then a lymphocytosis; oxygen and oxidising agents in general lead to a neutrophilia which amplifies the pulmonary parenchymal changes related to the release of toxic metabolites of oxygen. The inhalation of antigenic substances also disturbs the behaviour of alveolar cells: activation of macrophages in the presence of allergy in those sensitized to IgE and immediate attraction of neutrophils preceding a T lymphocyte alveolitis in hypersensitivity pneumonia. It is possible to categorise several patterns of reaction in intra-pulmonary cells when challenged by some insult, a direct cytotoxic action, the accumulation of inflammatory cells and immunological competence corresponding to the concept of "a neutrophil alveolitis" or a "T cell alveolitis" with the development of emphysematous lesions. An understanding of the cellular make-up present in the alveoli when reacting to an external pathogen enables a better approach to the pathophysiological mechanisms in question.

Air Pollutants↗