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Biomedical subjects

D Vervloet

Publications and source records attributed to D Vervloet.

At least 235 records · Page 13Linked to original sources
PubMed1980

A prospective national study of the safety of immunotherapy.

A prospective study was made in France to determine the frequency, nature, causes and consequences of systemic reactions occurring during specific immunotherapy. One hundred and fifty five reactions were recorded in 151, 997, injections given to 19,739 patients; a percentage of 0.1. It was higher with pollen extracts (0.2%) and practically nil with other extracts (house dust, Dermatophagoides, insect body, bacteria). Asthma, spasmodic rhinitis and urticaria were the most frequent, 80% of systemic reactions. In 59% no explanation could be found. The main known causes of adverse reactions were excessive doses of antigen, improper timing of treatment or incorrect technique of injection. After appropriate treatment the immunotherapy was continued in nearly 90% of the cases. Specific immunotherapy with the majority of extracts now being used, namely adsorbed extracts, is not dangerous but it must be precisely and cautiously done because errors are responsible for nearly 50% of the recorded systemic reactions.

Adolescent↗
PubMed1979

Anaphylactic reactions to muscle relaxants under general anesthesia.

Eleven patients who suffered a reaction to the administration of muscle relaxants during induction of general anesthesia were explored using skin tests, leukocyte histamine release, lymphocyte transformation test, and the Prausnitz-Küstner test (P-K). Fifteen normal subjects served as controls. Patients who suffered a reaction showed considerable cutaneous hypersensitivity to muscle relaxants. Leukocyte histamine release was positive in three cases and the P-K test was positive in one case. These findings suggest possible specific serum IgE antibodies to muscle relaxants. However, reliable discrimination between immunological and idiosyncratic pharmacological mechanism is difficult to obtain.

Anaphylaxis↗
PubMed1979

Cyclic AMP in hypersensitivity reactions.

Phytohemagglutinin (PHA) was capable of inducing non-cytotoxic histamine release from human leucocytes. In the presence of deuterium oxide (D2O), PHA caused significantly greater histamine release. Dibutyryl cyclic AMP (d-cAMP) could enhance the histamine release in the presence of D2O although it was an inhibitor of the release if used alone. However, a beta agonist, isoproterenol, which increases intracellular level of cAMP was inhibitory with or without D2O. These data ask the question about dual effect of cAMP and suggest the possibility of different polls of cAMP in the target cells.

Basophils↗
PubMed1978

Absolute determination of IgE antibodies to grass pollen allergens.

Knowledge of specific IgE bound on immunosorbent as assayed by RAST is useful but cannot give a complete description of the biological states of patients concerning IgE antibodies. Using a computer program based on a least squares error method and knowing the amount of bound specific IgE antibodies to grass pollen antigens in a serum at each of the four tested dilutions it is possible to calculate the absolute value of specific IgE antibody level, the relative value of affinity constant and the relative proportion of IgE antibodies to the total amount of specific (IgE plus non-IgE) antibodies. It is found that specific IgE antibodies account for high percentages of the total IgE protein (mean of 20%). High differences in affinity constant and in the proportion of IgE antibodies to the total amount of antibodies could be found between sera. Severity of grass pollen allergy could be related to the absolute level of IgE antibody, but no definite conclusion could be made on the importance of affinity constant and the proportion of IgE antibodies to the total amount of antibodies.

Allergens↗
PubMed1978

Histamine release reaction of basophils in chronic granulocytic leukaemia. Induction by heterologous anti-immunoglobulin E, concanavaline A, and phytohaemagglutinin; effect of heavy water.

Basophils possess membrane bound IgE molecules, and immunological activation leads to a secretory process with cell degranulation and histamine release. Heterologous anti IgE, concanavaline A, and phytohaemagglutinin are potent non-cytotoxic releasing agents. They operate by a mechanism similar to that of immunological activation. Heavy water is not a histamine releasing inducer but it increases histamine release of the cells. We studied the histamine release reaction of leukaemic basophils in 10 patients and found a physiological response such as that previously reported with normal human basophils.

Antibodies, Anti-Idiotypic↗
PubMed1978

Electron-microscopic study of the anaphylactic degranulation of human basophils from atopic subjects.

Leukocytes from subjects allergic to Dermatophagoides pteronyssinus were incubated for 20 min with a solution of D. pteronyssinus extracts. Histamine release was measured at 0, 3, 10 and 20 min. Simultaneously, samples were treated for electron microscopy in such a way as to correlate histamine release and the morphological aspects of basophil leukocytes. The principal features accompanying histamine release were: a progressive activation of the cytoplasmic membrane which showed long processes, densification of the mitochondria, fusion of granulations, progressive dissolution and exocytosis of the contents of the granulations, short segments of rough endoplasmic reticulum, active Golgi apparatus, and thin membrane-bound granules suggesting resynthesis of mediators.

Adult↗
PubMed1977

[Treatment of acute asthma. Comparison of the effectiveness of corticosteroids and of a combination of corticosteroids and an adrenergic beta-stimulant (author's transl)].

Two comparable groups of patients hospitalised for acute asthma received an intravenous infusion for two hours, containing corticosteroids in the first group and corticosteroids combined with an adrenergic beta-stimulant in the second. Course was assessed by the hourly measurement of forced expiratory volumen in one second (FEV1), heart rate and blood pressure. It was found that corticosteroids alone had a modest action (5,1% improvement in FEV1). By contrast, the combination of corticosteroids with an adrenergic beta-stimulant resulted in a rapid and pronounced improvement in FEV1 (19,9%), without producing any undisrable side-effects. No changes in arterial blood gases were noted under the influence of treatment. Injectable adrenergic beta-stimulants are therefore worthy of use in the treatment of an asthma attack, in the absencd of any contraindication.

Adrenal Cortex Hormones↗
PubMed1977

[Anaphylactic type of accidents due to myorelaxing agents during general anesthesia. Clinical and biological study].

Six patients who had suffered a reaction to the administration of muscle relaxants at the time of induction of general anaesthesia were explored using skin tests, the Prausnitz-Küstner reaction, the blastic transformation test, the Shelley test and the basophil histamine release test. Fifteen normal subjects were used as controls. The patients who had suffered a reaction showed considerable cutaneous hypersensitivity to muscle relaxants. None of the biological tests carried out revealed an immunological mechanism.

Anaphylaxis↗
PubMed1976

What can be measured with RAST?

A theoretical study of the basic principles involved in Radioallergosorbent test (RAST) showed that: 1) When a given serum is tested, the significance of the numerical value obtained with RAST depends upon the serum assayed and the allergosorbent preparation, in a rather unpredictable way. Three factors can be measured: a) The percentage of specific IgE antibodies among all allergen-specific antibodies; b) The specific IgE antibody level; c) The product of the specific IgE antibody level and its affinity constant. 2) Simple graphical techniques allow a straightforward determination of all these factors if four dilutions of each serum are assayed at the same time. The results are expressed in two constant parameters (arbitrary IgE unit and allergosorbent capacity). It is concluded that these theoretical calculations may give a fair account of a lack of correlation between specific IgE antibody levels (as assayed with RAST) and several clinical and biological parameters. Furthermore, they provide a simple procedure which makes such tedious manipulations as specific IgE antibody purification quite necessary.

Absorption↗
PubMed1976

Prostaglandins and asthma: The use of blood components for metabolic studies.

Experiments were carried out to study a possible role of prostaglandins (PGs) in the pathogenesis of human bronchial asthma. Leukocyte, plasma, and serum of ambulatory asthmatic as well as nonasthmatic individuals were used. PGF was measured by competitive radioimmunoassay with anti-PGF2alpha antibody. It was found that PGF was spontaneously released from the leukocytes of both asthmatic and nonasthmatic individuals. The PGF release as studied with the cells of asthmatic individuals was enhanced by the additions of arachidonic acid and/or dibutyryl cyclic AMP. Antigenic challenge of sensitive cells failed to show any general effect on the amount of PGF released. The amount of spontaneously released PGF had no correlation with the amount of maximal antigenic histamine release. Preincubation of the cells with arachidonic acid had no effect on subsequent antigenic histamine release. Plasma PGF levels in nonasthmatic and in asthmatic individuals were not significantly different and both were considerably lower than the serum levels. The mean serum PGF level in the asthmatic group was higher than in the nonasthmatic, indicating probably a greater release of PGF from blood cells.

Antigen-Antibody Reactions↗