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Biomedical subjects

B Hewitt

Publications and source records attributed to B Hewitt.

27 records · Page 2Linked to original sources
PubMed1985

Allergy in the Mediterranean area. III: Cross reactivity among Oleaceae pollens.

Pollens of closely related species often share common antigens and allergens although this is not always the case. Four species of Oleaceae pollens commonly found in the Mediterranean area were investigated for cross-reactivity: olive (Olea europaea), ash (Fraxinus exselsior), privet (Ligustrum vulgare) and Phillyrea angustifolia, a common bush. Twenty individual sera of patients allergic to Oleaceae were investigated for specific IgE antibodies against the four species of Oleaceae pollens. The results indicated a high degree of correlation between RAST titres of Oleaceae pollens but three gave a particular emphasis on one species only. Cross-reactivity among these four pollen species was sought by means of RAST inhibition, iso-electric focusing and tandem cross-immunoelectrophoresis. All tests revealed a high degree of cross reactivity although there is no total identity among these four pollen species.

Cross Reactions↗
PubMed1982

Staphylococcal and human dander IgE antibodies in superinfected atopic dermatitis.

Ten patients (Group 1) with Staphylococcus aureus superinfected atopic dermatitis (SAD) were compared with three control groups without SAD. One control group (Group 2) was comprised of ten atopic patients with total IgE levels of greater than 1000 u/ml, another control group, of six atopic patients (Group 3) with total IgE levels of less than 1000 u/ml and a third group, of ten non-atopics (Group 4), five of whom were infected with Staphylococcus aureus. Total and specific anti-staphylococcal IgE levels and anti-human dander IgE were high in Group 1. Specific IgE levels to S. aureus were slightly increased in some Group 2 patients but were normal (less than 7%) for Group 3. No specific IgE to human dander antigen was detected in either Group 2 or Group 3. In the non-atopic control group (Group 4), six out of ten patients had both low total, and specific IgE antibodies to both staphylococcal, and human dander antigens. Two had increased total IgE and specific anti-staphylococcal IgE antibodies, and two more with a severe, chronic infection, also had anti-staphylococcal IgE antibodies. In SAD patients, a good correlation was seen between cutaneous basophil hypersensitivity and high specific IgE antibodies against staphylococcal and human dander allergens. Delayed type hypersensitivity reactions to staphylococcal antigen were negative or poorly positive in the SAD group by comparison to controls. A paradoxical anaphylactic type of response to the offending bacterial agent in SAD patients, associated with 'auto-atopy' to human dander, is discussed.

Antibodies, Bacterial↗
PubMed1981

House dust allergy: correlation between in vivo and in vitro diagnostic tests.

Two different house dust preparations (house dust and fractionated house dust) were compared using intracutaneous skin tests and RAST assays in 91 patients suspected of house duct sensitivity. Total correlations of 54-64% (house dust) and of 68-74% (fractionated house dust) were obtained. The positive/positive correlations amounted to 52% (n = 66) and to 60% (n = 42) respectively. Seventeen patients were also tested by nasal provocation (NPT) and 33 by bronchial provocation (BPT) using the same house dust extract. Correlations between NPT and skin tests and NPT and RAST were 42% and 47% respectively and between BPT and skin tests and BPT and RAST 56% and 57% respectively.

Adolescent↗
PubMed1981

A comparative study of allergen extracts from cat fur, cat pelt and cat saliva.

Very good in vitro correlations were found among extracts of cat fur, cat pelt and cat saliva. Extracts were fractionated by isoelectricfocussing and tested by RAST and RAST inhibition. Some differences in allergenic composition were shown by RAST inhibition using a human serum pool and by titrating fractionated extracts against individual human sera, though the majority of the allergenic components of each extract appear to be common to all three extracts by these techniques. These in vitro data suggest that cat saliva could be a suitable source material for allergenic extracts for use in testing humans for cat hypersensitivity.

Allergens↗
PubMed1980

Cerebrospinal fluid involvement in patients with adult acute leukaemia and non-Hodgkin's lymphoma.

One hundred and thirty-four cases of adult acute leukaemia and 212 cases of non-Hodgkin's lymphoma treated by the Combined Haematology Division of Sydney Hospital over a four year period were reviewed to establish the incidence of central nervous system (CNS) involvement. The sole diagnostic criterion considered was positive cerebro-spinal fluid (CSF) cytology. The detected incidences of 21% and 5 . 2% respectively in long term surviving adults with leukaemia and those with non-Hodgkin's lymphoma are similar to other series. Unusual findings were the relatively low incidence of involvement in acute myelomonocytic leukaemia and unexpectedly high incidence in diffuse poorly differentiated lymphocytic lymphoma. Cytocentrifugation using the Cytospin has proved to be a useful technique in detecting small numbers of abnormal cells in the CSF.

Acute Disease↗
PubMed1980

Analysis of commercial pollen extracts by enzyme determination. I. Comparison of rast-inhibition assay and enzyme titration for orchard grass, rye grass and short ragweed pollen extracts.

Allergenic potency assessed by the 50% RAST-inhibition endpoint titration was compared with enzyme titration for the analysis of commercial pollen extracts. Six different extracts of short ragweed, orchard grass and perennial rye grass were examined. A good correlation (p < 0.01) was found between the acid phosphatase titers and allergenic potency of short ragweed and perennial rye grass extracts. A similar correlation (p < 0.01) was observed between leucin amino peptidase titers and allergenic potency of short ragweed extracts. No correlation could be found with orchard grass extracts. These findings suggest that enzymatic activity may provide a method for the control of certain commercial pollen extracts.

Acid Phosphatase↗
PubMedDate not supplied

Analysis of commercial pollen extracts by enzyme determination. II. Determination of the contamination of pollen extracts with plant matter.

The contamination of pollen extracts by plant matter was studied by means of enzymes. Beta-glucosidase was detected only in flowers and leaves by using the Api-Zym System. 29 pollen extracts were prepared after microscopic control. Among these 23 did not contain any plant matter and no beta-glucosidase activity could be detected. In contrast, 6 extracts were contaminated with plant matter and in every case beta-glucosidase activity was found 34 commercial pollen extracts completed the study. beta-glucosidase activity was present in 8 of them. It may be postulated that glucosidase activity detected using 2- naphthyl - beta D-glucopyranoside as a substrate, can be correlated with the presence of plant matter from the raw material from which the extract was prepared. This contamination may be important to determine since some additional sensitization may occur with such extracts during immunotherapy.

Drug Contamination↗