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Biomedical subjects

M D Topping

Publications and source records attributed to M D Topping.

32 records · Page 2Linked to original sources
PubMed1985

Clinical and immunological reactions to Aspergillus niger among workers at a biotechnology plant.

The workforce at a biotechnology plant producing citric acid by fermentation of molasses with a strain of Aspergillus niger was studied. A combination of a respiratory questionnaire and clinical assessment identified 18 subjects (4.9% of the workforce) with work related bronchospasm. In nine of these evidence of sensitisation to A niger was obtained by skin prick tests and radioallergosorbent test (RAST) using as an antigen an extract of the A niger culture fluid from the process. Of the 325 subjects without work related bronchospasm, only nine (2.7%) had a positive prick test. There were no subjects with symptoms of extrinsic allergic alveolitis. Investigation into the source of the antigen showed that whereas, in some areas of the plant, A niger spores were present, in others there were no detectable spores. In these areas, however, extracts of filters from air samplers were shown by RAST inhibition to contain A niger antigens, indicating that the culture fluid was generating airborne antigen. RAST inhibition studies showed that the A niger culture fluid used in the process contained antigens that were not present in a commercially available A niger extract, thus emphasising the importance in this type of investigation of using antigens prepared from material to which the workers are exposed.

Air Pollutants, Occupational↗
PubMed1984

Occupational allergy due to inhalation of ipecacuanha dust.

A number of workers packing ipecacuanha tablets were complaining of allergic symptoms. Skin-prick tests, RAST and an assessment of clinical history by interview were used to confirm the presence of work-related allergy. Specific IgE antibodies to ipecacuanha were detected and the occurrence of antibodies correlated with the incidence of allergic symptoms. The individuals with positive RAST scores had been employed, on average, longer than those with negative scores. It was found that atopy did not predispose the workers to work-related allergy and that there was no correlation between smoking and respiratory symptoms in this population.

Allergens↗
PubMed1984

Barn allergy among Scottish farmers.

Previous studies have shown that allergy to storage mites is a significant contributor to allergic disease among an isolated farming community in the Orkneys. The present study was undertaken to determine the prevalence of disease due to storage mites among farmers on the mainland of Scotland. Of the 290 subjects employed on 102 randomly selected farms studied, eighty-seven (30%) reported allergic symptoms on entering barns or byres, and prick tests to storage mites were positive in 62 (21%). Rhinitis and conjunctivitis together were the more frequently reported symptoms, with less than half the subjects recording respitatory symptoms. Specific IgE antibody to storage mites was detected in 43% of subjects reporting allergic symptoms associated with hay dust. Specific IgE to storage mites was strongly associated with atopy in those subjects who reported allergic symptoms.

Adult↗
PubMed1983

Renal dysfunction in cadmium smelters: relation to in-vivo liver and kidney cadmium concentrations.

Biochemical indicators of renal dysfunction have been compared with liver and kidney cadmium levels measured by neutron activation analysis in a group of 37 cadmium smelters. Higher than normal concentrations of cadmium in the liver reflect past exposure; they were associated with evidence of renal dysfunction in workers exposed to cadmium for more than 10 years. A small group of 6 workers exposed to cadmium for only a short time (mean = 4.6 years) had high hepatic cadmium concentrations but normal renal function. Longitudinal studies are required to establish the natural history of renal dysfunction following cadmium accumulation in industrial workers.

Cadmium↗
PubMed1983

Tetrachlorophthalic anhydride asthma: evidence for specific IgE antibody.

We describe seven women with asthma induced by occupational exposure to an acid anhydride, tetrachlorophthalic anhydride (TCPA), an epoxy resin hardening agent. Inhalation tests with TCPA at atmospheric concentrations of less than one tenth of a manufacturer's recommended exposure limit provoked asthmatic reactions in the four women tested. None had evidence of pretest bronchial hyperreactivity. Immediate skin prick test reactions were elicited in the seven subjects by a conjugate of TCPA with human serum albumin (TCPA-HSA) but not in others tested. Specific IgE antibody levels to TCPA-HSA, measured by radioallergosorbent test scores, were significantly elevated in the seven, but not in TCPA-exposed and unexposed comparison groups. These results imply that occupational asthma caused by TCPA is an allergic reaction mediated by specific IgE antibody.

Adult↗
PubMed1982

Castor bean allergy among workers in the felt industry.

We describe occupational allergy to castor bean in workers in a felt manufacturing plant. Twenty-six (37%) of the workers complained they were affected by the felt and were examined by us. Of these, 12 were considered to have occupational allergy. These 12 subjects had raised specific IgE levels to both felt and castor bean extracts. In addition, three subjects without occupational allergy had raised specific IgE. The presence of castor bean allergens in the felt was suggested by the correlation between the RAST scores to the felt and castor bean and confirmed by RAST inhibition experiments. The RAST results correlated well with the results of skin prick tests to felt and castor bean extracts. In addition it was found that atopy did not predispose the workers to castor bean allergy.

Allergens↗
PubMed1981

Allergenic activity of fractions of cocksfoot (Dactylis glomerata) pollen. Definition of active components by skin testing, and inhibition RAST.

With the combined use of skin tests, RAST and isoelectric focusing, a potency profile of a cocksfoot ((Dactylis glomerata) pollen extract was prepared. It was found that two fractions with pI 4.5 and 6.0 were the most allergenic, had the highest protein concentration and were also the most easily extracted. The importance of converting mean weal sizes into potency units when comparing the allergenicity of pollen fractions is emphasized.

Allergens↗
PubMed1981

Castor bean allergy in the upholstery department of a furniture factory.

In this study, undertaken to identify the cause of allergy in several upholstery workers in a furniture factory, the workers were handling several different materials, including glue, silicone spray, upholstery fabrics, and felt. Radio-allergo-sorbent test (RAST) assays showed that sera from sensitised workers contained specific IgE towards the felt; however, further investigations using RAST showed that the allergen was not the felt itself but a contaminant of the felt. The felt was manufactured from sacks, some of which had been used to store castor beans. The sera with raised IgE to the felt also had raised IgE to the castor bean extract. By means of RAST inhibition we confirmed that castor bean allergens in the felt were solely responsible for the raised IgE in the sera. The in-vitro RAST results were found to correlate well with the in-vivo pick tests and clinical symptoms.

Ricinus communis↗
PubMed1979

Activity units for allergen extracts.

The two present systems of units for the strength of allergen extracts, Noon and p.n.u. are both unsatisfactory. A new activity unit, based on skin prick in humans, is described, and its relationship to in vitro tests is explored. Potency limits for provocation materials used for skin prick tests are suggested.

Allergens↗
PubMed1978

Allergenic activity of fractions of cocksfoot (Dacylis glomerata) pollen.

A cocksfoot (Dactylis glomerata) pollen extract has been fractionated by isoelectric focusing in polyacrylamide gel, the separated components extracted from the gel and assayed by three methods: prick tests in human skin, RAST and PCA tests in monkey skin. Prick testing in human skin showed that subjects responded differently to the separated components, indicating the presence of more than one antigenic determinant, and a profile of antibody activity against each fraction could be constructed. In general, good agreement was observed between RAST profiles and skin test profiles, although some patients who gave positive skin tests lacked circulating IgE and consequently did not give a RAST profile or a monkey PCA. These studies emphasize the current difficulty in attempting to isolate a single pure allergen from cocksfoot which can be used either diagnostically for the detection of pollen allergy, or for the standardization of diagnostic extracts.

Adolescent↗
PubMed1977

Human dander in house dust allergy.

The possible role of human dander in house dust allergy was investigated. Naturally shed human mite-free skin squames were collected from bedding and used to prepare a human dander extract. When the extract was coupled to cyanogen bromide-activated paper discs, and used in the RAST assay, IgE titres to the skin extract were observed in the sera from several patients with house dust allergy. The sera with IgE to the skin extract also had high IgE titres to either house dust, D. pteronyssinus or cat fur. RAST inhibition studies revealed cross-reaction between the human skin extract and both a D. pteronyssinus extract and a cat fur extract.

Animals↗