Biomedical subjects

L Cornu

Publications and source records attributed to L Cornu.

At least 19 recordsLinked to original sources

PubMed2002

Decrease in ovalbumin-induced pulmonary allergic response by benzaldehyde but not acetaldehyde exposure in a Guinea pig model.

The pulmonary effects of two environmentally relevant aldehydes were investigated in nonsensitized or ovalbumin (OA)-sensitized guineapigs (GPs). Four-week-old male Hartley GPs, weighing about 400 g, were intraperitoneally injected with 1 ml of an NaCl solution containing 100 microg OA and 100 mg Al(OH)(3). They were then exposed to either acetaldehyde (200 ppb) or benzaldehyde (500 ppb) for 4 wk (6 h/d, 5 d/wk). At the end of exposure, GPs were challenged with an OA aerosol (0.1% in NaCl) and pulmonary functions were measured. The day after, guinea pigs were anesthetized and several endpoints related to inflammatory and allergic responses were assessed in blood, whole-lung histology, and bronchoalveolar lavage (BAL). Sensitized nonexposed GPs showed bronchial hyperresponsiveness to OA and an increased number of eosinophils in blood and BAL, together with a rise in total protein and leukotrienes (LTB(4) and LTC(4)/D(4)/E(4)) in BAL. In nonsensitized GPs, exposure to acetaldehyde or benzaldehyde did not induce any change in the tested parameters, with the exception of irritation of the respiratory tract as detected by histology and an increased number of alveolar macrophages in animals exposed to acetaldehyde. In sensitized GPs, exposure to acetaldehyde induced a moderate irritation of the respiratory tract but no change in biological parameters linked to the inflammatory and allergic responses. In contrast, exposure to benzaldehyde induced a decrease both in OA-induced bronchoconstriction and in eosinophil and neutrophil numbers in BAL, an increase in the bronchodilatator mediator prostaglandin E(2) (PGE(2)), and a decrease in the bronchoconstrictor mediators LTC(4)/D(4)/E(4). Further investigations are needed to determine if the attenuated response observed in sensitized GPs exposed to benzaldehyde is due to an alteration of the mechanism of sensitization or to a more direct effect on various mechanisms of the allergic response.

Acetaldehyde↗

PubMed1991

An attempt to evaluate lung aggression in monkey silicosis: hydrolases, peroxidase and antiproteases activities in serial bronchoalveolar lavages.

Exposure to silica can induce fibrosis and/or emphysema. Various factors such as proteases, other hydrolases and oxidants may be involved in the destruction of lung parenchyma. On the other hand, antiproteases play an important role in the protection of lung parenchyma against the action of proteases. We have developed an animal model of silicosis in monkey Macacus cynomolgus and followed these factors by bronchoalveolar lavage (BAL). We have studied glycosidases activities, elastase-like activity, immunoreactive alpha 1-protease inhibitor (alpha 1PI), neutrophil elastase inhibitory capacity (NEIC) and myeloperoxidase. Bronchoalveolar cells in serial BAL were also studied. Six monkeys were exposed to quartz aerosols (100 mg.m-3) for 18 wks. They were followed until they developed X-ray changes, which occurred between 21-64 wks after the end of the dust exposure. Cellular "silicotic nodules" were observed in lung biopsies. A control animal underwent serial BAL. Changes were seen in the differential cell count. The release of superoxide anion by bronchoalveolar cells obtained during the experiment was increased. Separation on a gradient of Percoll showed the presence of young macrophages, which exhibited enhanced release of superoxide anion as compared to the totality of bronchoalveolar cells. The biochemical analysis of BAL fluids obtained during and after the period of dust exposure showed an increase in glycosidases, alpha 1PI and NEIC. Some free elastase-like activity was simultaneously detected in BAL fluids from exposed animals but not from the control. This elastase-like activity was very low compared to NEIC. The increase in enzymatic and antiprotease activities occurred at different points in time for each animal, suggesting large differences in individual responses to dust, but occurred before the chest X-ray abnormalities.

Acetylglucosaminidase↗

PubMed1987

Comparison of hydrolases, peroxidase and protease inhibitors in bronchoalveolar fluid from Macacus cynomolgus and human controls.

1. Serial bronchoalveolar lavages were performed on a subhuman primate (Macacus cynomolgus) in order to give an experimental model for silicosis. 2. We have measured glycosidases, proteases, peroxidase and antiproteases of the BAL fluids from seven normal monkeys. 3. The results obtained were similar to those found in human control BAL fluids. 4. For monkeys, the repetition of the bronchoalveolar procedure does not seem to have an important influence on the values obtained. 5. The present results will now permit sequential follow up studies during the course of experimental silicosis.

Animals↗

PubMed1984

[Contribution to the study of event-related potentials in depressed patients].

When we want to quantify an experimentation on an individual presenting behaviour troubles, the problem we are faced with is the relative inadequacy between the techniques that are used and the patient. The aim of this research is a study of the evolution of the differential analysis of power spectra and alteration in the repartition of VEP amplitudes on 18 depressed adults before and after antidepressive treatment. Control in healthy adult volunteers has been realised. The originality of the method used is in the analytical techniques and selected tests. It is difficult to state positively that VEP morphology represents a pertinent criterion in the study of the evolution of a depressed syndrome. But the results which are obtained show a similar evolution between VEP morphology and clinical criterion. This is in conformity with numerous present studies which consider VEP as a pertinent sign in a psychophysiological process.

Adult↗

PubMed1983

[Age and photopic and mesopic visual acuity].

Visual acuity at high luminance (100 cdm2) and at low luminance (0.8 cdm2) was measured in normal subjects aged between 20 and 50 years. A decrease of visual acuity at Low luminance was noted with increasing age whereas high luminance acuity remained unchanged (20/20). At thirty years of age, low luminance visual acuity was an average of 20/30 decreasing at 40 years to 20/40. Results were confirmed by statistical analysis. A short study with interference fringes, formed by a coherent light (neon-helium laser) produced directly on the retina and thus by-passing optical effects on the eye, suggested that the retina-brain system was responsible for decreased mesopic visual acuity, night myopia or right presbyopia not playing any part in this decrease as suggested by some authors. Consequences of these findings, concerning particularly workers at low luminance such as pilots or drivers, are discussed.

Adult↗

PubMed1981

Visually emitted potential and attentional processes.

Visually emitted potentials were recorded during a series of 450 stimulations with a frequency of 1 per second, during which 10% were voluntarily omitted by the experimenter, either regularly or at random. The recordings summed up here show the presence of a potential emitted in the form of a late positive wave (350 ms) preceded by a negative wave (200 ms) when the subject mentally counted the omissions (regular or random). This leads us to believe that the subject's attention is more determinant than the random distribution of omissions.

Adult↗

PubMed1980

Visual evoked potentials and sensory dimensions.

Concomitant variations of physical stimulus characteristics and variations of responses elicited in the human adult subject were studied under conditions of adaptation to darkness or light in order to stimulate the B or the D sub-system described by Jung. Temporal processing in these two systems was compared by analysing output variables (VEPs and sensory ratings) in response to a range of electrophysiological and perceptual responses run in parallel: the temporal summation law, which is a basic code in the nervous system, is found to be obeyed in both B and D subsystems. But asymmetries are also observed, indicating specific characteristics of B and D functioning.

Adult↗

PubMed1980

[Spectral band analysis in the study of attentional processes: interest of numerical filtrage by bands].

This is a study of relationships between cerebral events and visual attentional processes in 28 healthy adult volunteers by means of a spectral analysis method described in this paper. The recorded data make it possible to study the EEG, standard VEPs, VEPs during attention and visual 'emitted' potentials when stimuli were expected but absent. Compared with the methods of summation and unitary analysis, spectral analysis by bands appears very interesting, especially for the study of 'emitted' potentials because it avoids the subjectivity of operators and reduces the number of stimuli. The results obtained show the interest of this simple, reliable and effective method for the detection and objectivation of evoked activities with only a very few (10) stimuli.

Adult↗

PubMed1979

[Emitted cerebral activity and attention processes in a group of schizophrenic methodologic problems].

This is a study of the relationship between cerebral events and visual attentional processes of schizophrenic patients by means of a spectral analysis method described in this paper. With recorded data it is possible to study the EEG, standard visual evoked potential, visual evoked potention with attention and visual 'emitted' potentials when stimuli were expected but absent. Compared with the summation method and unitary analysis, the spectral analysis method appears very interesting, especially for the study of 'emitted' potentials because it avoids the subjectivity of operators and reduces the number of stimulations. The results show the interest of this simple reliable and effective method for the detection and objectivation of evoked activities with only very few (10) stimulations.

Attention↗

PubMed1979

["Emitted" cerebral activity and attention processes in a group of schizophrenics. Methodologic problems].

This is a study of the relationship between cerebral events and visual attentional processes of schizophrenic patients by means of a spectral analysis method described in this paper. With recorded data it is possible to study the EEG, standard visual evoked potential, visual evoked potention with attention and visual "emitted" potentials when stimuli were expected but absent. Compared with the sommation method and unitary analysis, the spectral analysis method appears very interesting, especially for the study of "emitted" potentials because it avoids the subjectivity of operators and reduces the number of stimulations. The results show the interest of this simple reliable and effective method for the detection and objectivation of evoked activities with only very few (10) stimulations.

Attention↗

PubMed1978