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Biomedical subjects

J C Bessot

Publications and source records attributed to J C Bessot.

At least 19 recordsLinked to original sources
PubMed1992

[Occupational asthma].

The diagnosis of occupational asthma requires the integration of a multiplicity of data; the history, cutaneous skin tests, biological tests, respiratory function tests and non-specific tests of bronchial hyperreactivity and specific bronchial provocation test. The history search for the presence of an atopic state, the occurrence of similar disorders in members of the same firm and also the timing of symptoms in relation to the occupational activities. Cutaneous tests are particularly helpful in IgE-mediated asthma in relation to the inhalation of animal or vegetable materials of glycoprotein origin. For haptens, the need for their prior coupling to a protein carrier causes problems which have not been entirely resolved. Laboratory tests run into the same snags. Respiratory function and non-specific bronchial provocation tests, confirm the diagnosis of asthma and enable the medium and long term prognostic to be assessed. Specific bronchial provocation tests are the most appropriate tests to establish an aetiological diagnosis in occupational asthma. Different technical methods are possible: quantitative administration of allergen aerosols, realistic tests, and tests using exposure chambers to achieve true test doses. The products responsible for occupational asthma are multiple. The different substances are characterised in a simplified manner: first animal matter (mammalian and arthropod allergens), secondly substances of vegetable origin (roots, leaves, flowers, grain and flour, wood and its derivates) and finally chemical products. The chemical products are primarily from the pharmaceutical and metal industries and above all from the plastics industry.

Allergens↗
PubMed1992

[Occupational asthma caused by ebony wood].

A case of occupational asthma to ebony wood dust is described in a violin and stringed instrument maker, who was sanding and filing ebony to make the finger boards of violins and cellos. The diagnosis was confirmed using a realistic provocation test; after sanding and smoothing the ebony for 20 minutes the patient developed bronchial spasm with fall of the force expired volume in one second (VMS) of 45% which was reversible following the inhalation of beta 2 agonists. A delayed reaction was seen at 3 hours and 6 hours and at 20 hours after the test. The observations of occupational asthma or rhinitis to ebony wood are very rare. To our knowledge there are two publications at the present time. It has been recognised as an occupational disease (see table 47 of occupational diseases) and an exclusion order has been effected.

Adult↗
PubMed1991

[Asthma due to isocyanates in a theoretically non-exposed worker].

We report a case of isocyanate induced asthma in a patient who had been previously exposed to isocyanate and had become a porter in a factory producing polyurethene foam. The test for exposure to TDI was positive. The recognition of occupational asthma was nevertheless challenged and the patient was not considered to be carrying out work involving exposure to the inhalation of isocyanates. The effect of a change of job in the development of occupational asthma, and the risk of asthma induced by isocyanates despite inhaled concentrations inferior to the VME, the difficulty of obtaining a recognition of occupational asthma when the working conditions fulfilled do not exactly correspond to those labelled in the schedule for occupational diseases, are discussed in this paper.

Adult↗
PubMed1989

Platelet function: aggregation by PAF or sequestration in lung is not modified during immediate or late allergen-induced bronchospasm in man.

Among the mediators involved in the pathophysiologic mechanisms that underly the reactions of the acute and delayed phases of bronchospasm induced by allergens in man, platelet-activating factor (PAF) could play an important role, in particular by its effects on platelets. In animals, inhalation or injection of PAF causes a platelet-dependent bronchoconstriction that is blocked by prior administration of an antiplatelet antiserum and accompanied by platelet accumulation in the pulmonary vessels. In man, inhalation of PAF causes a bronchospasm and induces a bronchial hyperreactivity. Abnormalities of platelet aggregation and the secretion into plasma of platelet factor 4 and beta-thromboglobulin have been described in patients with asthma during induced bronchospasm. Platelet functions have been studied in 15 patients with asthma before and after allergen bronchial provocation tests. There was no difference between platelet counts, plasma concentrations of platelet factor 4 and beta-thromboglobulin, and platelet aggregation induced by several agonists (adrenaline, arachidonic acid, or PAF) before and immediately after the allergen bronchial provocation test. There was no platelet pulmonary sequestration as studied with 111Indium-labeled platelets during 24 hours after the antigen challenge, and the life span of circulating platelets was normal. Our results do not support an important direct role for PAF in the pathophysiology of asthma. It is still possible that the current methodology is too insensitive to detect amounts of PAF in the circulation or that PAF is acting locally.

Adolescent↗
PubMed1989

[Effect of the environment on the development of respiratory allergies].

Allergy reactions may be regarded as resulting from exposure to allergens of subjects who are genetically predisposed to synthesize IgE. The presence of allergens in the environment is necessary to acquire sensitization. With some allergens, sensitization seems to develop very rapidly. The introduction or presence in the environment of certain allergens, such as house dust mites, may increase the prevalence of asthma. Despite conflicting reports, in atopic subjects exposure to pet animals also is a risk factor. Introducing foreign proteins prematurely into infant's food has been considered a factor that facilitates the development of allergic diseases. Contact with occupational allergens results in allergic manifestations in less than one-third of the subjects exposed, which suggests that genetic factors play a predisposing role. Beside exposure to allergens, non-specific environmental factors, such as chronic inhalation of tobacco smoke or atmospheric pollutants (e.g. ozone, SO2, NO2, particles of burnt fuels) might contribute to sensitization. The part played by viral infections (RSV or influenza virus) in the triggering of allergic diseases has often been reported. Interactions between irritants and allergens may encourage the development of respiratory allergy.

Acari↗
PubMed1988

Guanine and mite allergenicity in house dust.

Guanine is the major nitrogenous waste product in arachnids. It may serve as an indicator for allergenic mite faecal pellets. The present study assesses the correlation between the mit allergenicity of different house dust (HD) samples and their guanine content. Guanine content in HD samples was evaluated either by the Acarex-Test or determined quantitatively, especially for in-vitro methods. Using intradermal tests in selectively sensitized Dermatophagoides pteronyssinus (Dpt) patients, we evaluated the mite allergenicity of eight extracts obtained from HD samples with varying guanine contents. The weal area appeared to be proportional to the HD samples' guanine content. A three-fold increase in skin reactivity was observed when the guanine content varied from 0.06% to more than 1%. Patients allergic to HD but not to Dpt had no significant reactions with HD extract prepared from a guanine-rich HD sample. For eighteen different HD samples coupled to paper discs, the percentage Dpt RAST binding values obtained with a Dpt-selectively sensitized patient serum pool was correlated with the guanine concentrations of HD samples (P less than 0.01). The potencies of different HD extracts obtained from HD samples that varied in guanine content were also clearly distinguished on histamine-release titration curves. House dust obtained from homes at high altitude or from hospitals was generally guanine free. The HD sample guanine contents in homes where twelve Dpt-sensitized patients experienced symptoms were significantly higher than in homes where these patients were symptom free. The guanine colour test, a quick and easy technique, represents an important new development in indoor environmental investigations. It makes it possible to demonstrate mite faecal exposure and can be used to monitor the effectiveness of mite allergen avoidance measures.

Allergens↗
PubMed1979

Inhibition experiments with solid phase mite or epithelia in house dust hypersensitivity.

The present study was undertaken to verify that mites are not the only allergens in house dust extracts and that other allergens such as cat epithelia can also be responsible for house dust hypersensitivities detected both by house dust skin tests and house dust RAST studies. In order to determine whether mite or epithelia fixed on a solid phase could remove not only the IgE antibodies reactive with the homologous allergens, but also the IgE antibodies reactive with house dust allergens, the authors have absorbed 10 sera of house dust allergic patients with solid phase mite or epithelia. The absorption procedure removed a large part of the IgE antibodies reactive with specific immunosorbent (Dermatophagoides pteronyssinus or cat epithelia) and in the same way the IgE antibodies reactive with house dust immunosorbent. The percentage of RAST inhibition varied from 65% to 92% for Dermatophagoides pteronyssinus and from 65% to 94% for house dust in patients allergic to house dust and mite; the percentage of RAST inhibition varied from 67% to 92% for cat epithelia and from 73% to 90% for house dust in patients allergic to house dust and cat epithelia. This is in accordance with the hypothesis that house dust is not an allergen per se, but rather a complex mosaic of several allergens including mite, animal epithelia, etc.

Absorption↗
PubMed1979

[Clinical, pathologica and genetic analysis of 53 cases of broncho-pulmonary cancer, still surviving after 5 years (author's transl)].

The authors take up again the clinical, pathological and genetic analysis of 53 bronchial cancers with a survival exceeding 5 years. The operation samples were reexamined; a H.L.A. grouping was done in every cases. On the whole, it concerned patients under 60 in good general condition; the extension of their lesions only required a limited exeresis (lobectomy). The epidermoid form predominates, the lymph node invasion is rare. Seventy four per cent of the patients carry at least one of the following antigens: W 19, A 10, B 5, BW 35. But the study did not prove the existence of a genetic factor conditioning the survival.

Bronchial Neoplasms↗
PubMed1978

[Hereditary antithrombin III deficiency causing recurrent thrombo-embolic problems (author's transl)].

A marked deficiency in antithrombin III (AT III) was demonstrated in a 39-year-old man suffering from recurrent thrombo-embolic problems. The patient's father had died following a thrombo-embolic disorder. A certain number of members of the family also showed evidence of a marked decrease in AT III levels. Although it was not possible to study the patient's parents, it would seem reasonable to conclude that the diagnosis was one of hereditary deficiency in AT III. The various aspects of this disorder discovered by Egeberg are reviewed: early onset, in several members of the same family, or recurrent thrombo-embolic problems, accompanied by a decrease in functional activity of one of the principal inhibitors of thrombin (AT III), with autosomal dominant transmission and treatment based upon anti-vitamin K agents.

Adult↗
PubMed1977

Correlation between skin tests, inhalation tests and specific IgE in a study of 120 subjects allergic to house dust and Dermatophagoïdes pteronyssinus.

The radioallergosorbent test was compared with currently accepted allergy diagnostic techniques in seventy-four controls and 120 patients with a clinical history of allergy to house dust and Dermatophagoïdes pteronyssinus. The results obtained with D. pteronyssinus allergen extract show a close correlation between the size of the cutaneous reactions and the serum level of allegen-specific IgE. On the other hand, highly positive skin tests to house dust were not always correlated with a positive RAST response for house dust. Similar results were found with inhalation tests. When a purified D. pteronyssinus extract was used, a stronger relationship was observed between RAST, cutaneous and inhalation tests. It can be assumed that RAST for house dust is not of value in patients with house dust and mite allergy. Our findings indicate that the correlations between RAST results and other in vivo test results depend on the purity of the allergen extracts and the selection of patients.

Administration, Intranasal↗
PubMed1977

["Immuno-allergic" complications of rifampicin therapy].

From 8 cases of immuno-allergic accidents attributed to Rifampicine, the authors review the literature on the subject. The "flue like" syndrome is the most frequent and characteristic of those accidents, worsened by haematological and renal involvements. These accidents probably belong to a pathology of immuno-complexes in relaiton with the production of anti-Rifampicine antibodies. Among the different means of in vitro diagnosis, the test with the anti-complement antiglobulin is the most reliable, though not always in good correlation with clinical signs. Though rare and most often benign, these accidents should lead to prudence in treating recurrent tuberculosis or reusing Rifampicine after a momentary interruption.

Aged↗