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Biomedical subjects

J R Joubert

Publications and source records attributed to J R Joubert.

49 records · Page 3Linked to original sources
PubMed1981

Food allergy - a definition.

Routine radio-allergosorbent test (RAST) were plotted as the percentage binding to specific RAST allergen discs versus serum IgE levels. Patients with a positive result on testing with food allergen discs were divided into those responding to food allergen discs only and those responding to food and other allergen discs. This division parallels that found in patients infested with Ascaris lumbricoides when a RAST for A. lumbricoides is carried out. It is suggested that the term 'food allergy' be reserved for those patients giving a polyclonal IgE response to ingested food.

Adolescent↗
PubMed1981

[The effect of steroid therapy on cytological and histopathological changes during experimental extrinsic allergic alveolitis (hypersensitivity pneumonitis)].

Acute extrinsic allergic alveolitis was experimentally induced in rabbits using horseradish peroxidase (HRP) as antigen. Broncho-alveolar lavage was performed on the excised lungs and total and differential cellular yields determined, and correlated with the histopathological changes in the lungs as well as the total and differential white blood cell counts. After a single parenteral immunization with HRP without adjuvants, and weekly aerosol challenges with nebulized HRP solution for 3 consecutive weeks, a 3-fold increase in the total cell count as well as a very pronounced rise in the percentage of lymphocytes was noticed. Histopathologically, the bronchi-associated lymphoid tissue (BALT) became more prominent, an increase in the number of foreign body giant cells was noticed and a focal interstitial and intra-alveolar accumulation of lymphocytes, granulocytes and macrophages could be demonstrated, as well as a mild hyperplasia of type 2 alveolar epithelial cells. Intramuscular injections of methylprednisolone acetate (Depo-Medrol) every 72 hours induced a pronounced peripheral lymphopenia, thymic involution and an almost complete disappearance of the BALT in both the control and HRP-challenged rabbits. Similarly, a marked decrease in the total cell count and percentage of lymphocytes was noticed in the broncho-alveolar fluid of the animals with hypersensitivity pneumonitis. No signs of interstitial or intra-alveolar reactions were seen in the lungs of the experimental animals after 3 weeks of aerosol antigen challenge when treated with steroids. Collectively, these data suggest that the development of hypersensitivity pneumonitis was, at least in part, due to a cell-mediated immunological reaction in the lung. This animal model in which steroid suppression of experimental allergic alveolitis has been demonstrated, may be employed to elucidate the cellular pathogenesis of this disease process.

Alveolitis, Extrinsic Allergic↗
PubMed1980

Interstitial lung disease. Part I. A multidisciplinary approach to the diagnosis and assessment of disease activity.

The value of alveolar lavage as an investigative technique was determined in patients with interstitial lung disease. Alveolar cytology was related to defined histopathological degrees of disease activity found in transbronchial biopsy specimens. The degree of disease activity as assessed by these two techniques was compared with radiological evaluation. Adequate specimens of lung tissue for histopathological evaluation were obtained by transbronchial biopsy in 95% of the subjects during the first procedure and diagnostic histopathological changes were found in 60% of the patients. In the evaluation of disease activity, the lymphocyte-macrophage (L-M) ratio and, to a lesser extent, the total alveolar cell counts correlated well with graded histopathological changes of activity. A graded radiological evaluation of activity was accurate in 14 out of 17 patients, but in 3, extreme cellular disease ws not recognized. Alveolar cytological examination can be employed as a supplement to the biopsy technique for increased accuracy in the initial and follow-up evaluation of active interstitial lung disease. An approach combining transbronchial biopsy, alveolar lavage and radiography, provides a safe and accurate alternative to openlung biopsy in most patients for determining the aetiology and degree of activity of interstitial lung disease.

Adolescent↗
PubMed1980

Ascaris lumbricoides and the human immunogenic response: enhanced IgE-mediated reactivity to common inhaled allergens.

The relationship between the IgE-mediated immunogenic response to Ascaris and similar responses to common inhaled allergens was determined. Sixty-six of 170 allergic asthmatics from an area in which Ascaris infestation was endemic had positive skin-prick reactions to Ascaris antigen. The number and size of skin-prick reactions to common inhaled allergens were greater in this group than in the 104 Ascaris-negative allergic asthmatics. Specific serum IgE antibodies were determined by the radio-allergosorbent test. The serum IgE levels for Ascaris and three common inhaled allergens correlated well with the skin reactions induced by the same antigens. Total IgE and serum IgE antibody levels for the three inhaled allergens were higher in patients who had positive results on skin testing with Ascaris antigen than in those with negative results. There was no similar association between Dermatophagoides pteronyssinus and six common inhaled allergens. An Ascaris-induced immune response was associated with enhanced IgE-mediated reactivity to common inhaled allergens in both allergic and clinically non-allergic subjects.

Adolescent↗
PubMed1979

Ascaris lumbricoides and allergic asthma: A new perspective.

Infestation of humans with the parasite Ascaris lumbricoides may induce high total serum IgE levels, but the influence of this immunogenic response on allergic asthma has not been defined. In this study, the specific antiparasitic IgE-mediated response as determined by skin-prick testing was related to the incidence of allergic asthma in Ascaris-infested patients. A limited number--17% of the non-allergic controls and 51% of the allergic asthmatics--had a clinically detectable immunogenic response to the parasite. The predicted incidence of asthma was significantly higher than the observed incidence in the subjects in whom the Ascaris skin test was positive. This was not found in subjects in whom the Ascaris skin test was negative. Inhalation of Ascaris antigen induced asthmatic reactions in 7 of 8 patients who were Ascaris-positive on skin testing, but not in the negative controls. The groups of patients who respond immunogenically to parasite infestation need to be defined, as they may be predisposed to allergic diseases such as asthma.

Adolescent↗
PubMed1976

Acute hypersensitivity pneumonitis in the rabbit. I. An animal model with horseradish peroxidase as antigen.

An experimental model of acute hypersensitivity pneumonitis was developed in rabbits using horseradish peroxidase as antigen. The lesion, produced by aerosol challenge with horseradish peroxidase 21 days after a single parenteral immunization with horseradish peroxidase and complete Freund adjuvant, was characterized by diffuse infiltration of respiratory bronchioles and of alveolar ducts and walls with approxomately equal numbers of mononuclear cells (lymphocytes and macrophages) and polymorphonuclear cells. This lesion, which was specific for the antigen, was distinct from the variable granulomatous component that was directly attributable to the use of complete Freund adjubant. Development of the lesion did not correlate with the humoral immune response, as indicated by antigen-binding, precipitin, and homologous passive cutaneous anaphylaxis assays, by negative serum transfer studies, by lack of correlation with immediate and intermediate Arthuslike) skin reactivity, by absence of electron microscopic and immunofluorescent evidence for immune complex processes, and by lack of evidence for complement activation. Development of the lesion did correlate with delayed (12- to 48-hour) skin reactivity, although rigid identification of cell-mediated immunity was not possible on histologic examination.

Acute Disease↗
PubMedDate not supplied

Determination of airway hyper-reactivity in asthmatic children: a comparison among exercise, nebulized water, and histamine challenge.

An easy and accurate method of assessing bronchial hyper-reactivity could be of great value in identifying and classifying the degree of severity of asthma in children. The sensitivity and specificity of three methods of provocation, ie, histamine, nebulized water, and exercise, were compared in 20 asthmatic and 20 control children between ages 5 and 13 years. Three clinical categories of severity ranging from slight (Group 1) through moderate (Group 2) to severe asthma (Group 3) were identified. The three methods were compared in each subgroup for detecting a tendency to bronchospasm. An inverse correlation (-0.57) was found between the histamine dose and clinical degree of severity, whereas distilled water and exercise proved to be too insensitive for identifying Group 1 asthmatics. Histamine challenge in children is a safe and sensitive technique for identifying asthma and for monitoring the severity of the disease during follow-up.

Adolescent↗