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Biomedical subjects

L Belin

Publications and source records attributed to L Belin.

At least 37 records · Page 2Linked to original sources
PubMed1989

Isocyanate exposure and hypersensitivity pneumonitis--report of a probable case and prevalence of specific immunoglobulin G antibodies among exposed individuals.

A car painter experienced three episodes of a hypersensitivity pneumonitis-like disease after exposure to two-component acrylic lacquers with hexamethylene diisocyanate (HDI) as the curing agent. High titers of HDI-specific immunoglobulin (Ig) G antibodies were found in the patient's serum by means of enzyme-linked immunosorbent assay (ELISA). In the ELISA, 5 to 10% of the sera from 455 isocyanate-exposed but asymptomatic workers were positive, depending on the criterion used for a positive test, whereas 0% of the sera from 157 unexposed referents was found to be positive. Among 10 subjects with isocyanate-induced asthma and isocyanate-specific IgE antibodies, 50% had specific IgG. It was concluded that the presence of isocyanate-specific IgG antibodies in serum is correlated with isocyanate exposure rather than with symptoms of isocyanate-induced disease.

Adult↗
PubMed1988

Longitudinal study of specific IgE and IgG antibodies in a patient sensitized to ethylene oxide through dialysis.

IgE and IgG antibodies to ethylene oxide (EO) were monitored by RAST and by ELISA in serum from a patient with hypersensitivity reactions during hemodialysis. Serum samples from the patient covering a 7-year period were analyzed. The changes in titers of IgE and IgG antibodies correlated to the time of EO exposure as well as to clinical symptoms. EO-specific IgG antibodies were, however, also found in sera from hemodialysis patients without any hypersensitivity symptoms. Assay of specific IgG antibodies will only indicate whether a patient has been exposed to, and immunostimulated by, EO, whereas specific IgE antibodies appear to be clearly related to hypersensitivity symptoms. The hapten and carrier specificity of EO-induced IgE antibodies was studied. The antibodies were found to be solely hapten specific because carriers of different types could be used in RAST without changing the outcome of the test. The existence of new antigenic determinants related to the carrier could not be demonstrated.

Adult↗
PubMed1988

Breed-specific dog-dandruff allergens.

Fifty-one patients with clinical history of dog allergy were skin prick tested with eight individual standardized dog breed-allergen preparations, one mixed breed-allergen preparation (Poodle/Alsatian), dog-serum albumin, and histamine hydrochloride, 1 mg/ml. All extracts were characterized by crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis with a pool of sera from patients clinically sensitive to dog. The dog-breed extracts contained common antigens/allergens, as well as components represented only in one or two dog-breed extracts. The concentration corresponding 1000 BU/ml varied from 16 to 100 micrograms of protein per milliliter. The sensitivity of skin prick test was 67% to 88% for the various dog breed-allergen preparations, but only 18% for dog-serum albumin. Significant difference between the skin test response to different dog breed-allergen preparations indicating dog breed-specific allergens was obtained in 15% of the patients. There was no significant correlation between skin prick test results and symptoms related to a specific dog breed.

Adolescent↗
PubMed1988

Assay of specific IgE antibodies to disodium cromoglycate in serum from a patient with an immediate hypersensitivity reaction.

A 29-year-old man with pollen allergy had experienced immediate adverse reactions, such as itching of the eyes, rhinitis, wheezing, and general urticaria, after using disodium cromoglycate (DSCG) eye drops. The local symptoms were reproducible, and skin tests were strongly positive. With serum from the patient, a RAST was developed for the assay of IgE antibodies. The uptake on RAST disks was 6% of the total activity added, which was a significantly higher level than was found in sera from 35 randomly selected blood donors or in sera from 25 patients tolerating DSCG. By addition of DSCG to the patient's serum, 95% of the binding to paper disks could be inhibited. The induction of specific IgE antibodies was proposed to be a result of a combination of electrostatic and hydrophobic interaction of DSCG and a protein carrier. The substance would thus act as a hapten without any covalent binding to the carrier. DSCG may serve as a model for other nonreactive low-molecular-weight substances suspected to elicit type I-like adverse reactions.

Adult↗
PubMed1988

Exposure to microorganisms, airway inflammatory changes and immune reactions in asymptomatic dairy farmers. Bronchoalveolar lavage evidence of macrophage activation and permeability changes in the airways.

Lung function, bronchial reactivity, serum antibody levels, bronchoalveolar lavage (BAL) fluid and the magnitude of exposure to airborne microorganisms during farm work were studied in 10 healthy farmers with no respiratory symptoms. Lung function and bronchial reactivity were not altered. An increase in the amount of antibodies against several microorganisms could be demonstrated but precipitating antibodies were observed only in two subjects. In the BAL fluid the nonsmoking farmers had elevated proportion of lymphocytes and elevated levels of albumin, fibronectin and angiotensin-converting enzyme while the levels of hyaluronan and procollagen III N-terminal peptide were within normal limits. The lung function, bronchial reactivity, serum antibody levels and BAL findings were not correlated with the exposure to airborne microorganisms. We conclude that healthy farmers, exposed to mold dust, may exhibit signs of alveolitis including albumin leakage, accumulation of inflammatory cells and alveolar macrophage activation.

Adult↗
PubMed1987

Biological equilibration of allergen preparations: methodological aspects and reproducibility.

A method for biological equilibration (BE) of allergen reference preparations using the skin-prick test (SPT) method and histamine HCl 10 mg/ml as reference substance (reference method), was evaluated. The precision was low for weals less than 10 mm2. The slope (log weal area/log concentration) of allergen and histamine did not vary significantly between investigators and allergens. The median slopes were 0.39 (n = 384) and 0.34 (n = 397), for allergen and histamine, respectively (P less than 0.01). The concentration of allergen eliciting a weal of the same size as that of histamine HCl 1 mg/ml (Chl) in the median sensitive patient, 1000 Biological Units/ml (BU/ml), did not vary significantly between clinics/geographical regions (grasses, mites and moulds). As BE is repeatable between regions, BUs estimated by this method are generally valid. A high correlation (r = 0.91, P less than 0.001) was found between the median Chl as estimated with histamine 1 and 10 mg/ml as reference substance, respectively. Thus, this reference method for BE is valid. The precision of the SPT method with histamine HCl 1 mg/ml is not as good as with 10 mg/ml, which is therefore recommended as the reference concentration.

Adolescent↗
PubMed1987

Results of biological standardization with standardized allergen preparations.

The aim of biological standardization (BS) is to equilibrate the activity (potency) of allergen extracts from different source materials. This was done by performing skin prick tests (SPT) on patients who were sensitive to one of the following 10 allergens: Birch, alder, hazel, timothy, rye grass, velvet grass, cultivated rye, mugwort, D. farinae and Cladosporium herbarum. Patient sensitivity varied within a range of three to four powers of ten for each allergen investigated. The weal size in each patient corresponding to that elicited by histamine 1 mg/ml was calculated using the model log (mean weal diameter) = a + b log (concentration). The correlation coefficients of the regression lines of the allergen dose response relationship were found to be greater than 0.85 in most cases. The median slope for all extracts was 0.24. The slope for Cladosporium was significantly steeper than that for pollens. The amount of material in microgram dry weight (d.w./ml) equal to 1000 biological units/ml (BU/ml) varied within a factor of three between species for all tested purified allergen preparations but Cladosporium. For Cladosporium, about 30 times more material was needed than for D. farinae. When using crude rather than purified material, it was necessary to use five to ten times more to elicit a reaction corresponding to 1000 BU/ml, but the difference was significant only for Cladosporium. The narrow range of allergen concentrations used by us as well as other investigators does not assure positive skin prick test results in all patients with clinical symptoms due to the allergen in question. Skin prick testing should therefore be done over a wide range of concentrations to improve the methods for BS.

Allergens↗
PubMed1987

Sawmill alveolitis in Sweden.

Short-lasting alveolitis-like symptoms are described in Swedish sawmill workers who are trimming and sorting moldy planks. Precipitating antibodies to Rhizopus antigen are demonstrated by double diffusion analyses in more than 50% of the wood trimmers, who are exposed to greater than 10(6) Rhizopus colony-forming units/m3 (Rcfu/m3). Febrile reactions with muscular pain and malaise occur in 10-20% at peak exposure levels above 10(7) Rcfu/m3. Sawmill workers with repeated acute symptoms have high titres of precipitating antibodies and are mainly non-smokers. The prevalence of this disease in the total Swedish wood trimmer population is estimated at 5-10%. Less typical symptoms from upper and lower airways and a mild, reversible decrement of forced vital capacity over one week's work shift is also suspected to be caused by this airborn mold. The pathogenetic mechanism is assumed to be identical with the wood mold reactions in wood chip burners, where a more complete picture of typical allergic alveolitis is seen. Identification of the cases and preventive measurements seem to have reduced the incidence rate of both these wood mold diseases.

Air Microbiology↗
PubMed1986

Lung function and rhizopus antibodies in wood trimmers. A cross-sectional and longitudinal study.

Pulmonary function was studied in 66 wood trimmers exposed to organic dust (moulds) after a month of no exposure (summer vacation) and then three and 27 months later, and also during a working week. The results of forced expirometry and single breath nitrogen washout were compared with those obtained in local controls and in larger reference materials. The forced vital capacity (FVC) and forced expired volume in one second (FEV1) were reduced by an average of 0.4 and 0.31, respectively, after one month of no exposure, however, the nitrogen washout variables showed no clear changes. Repeated measurements three months later on a Monday morning after two days of no exposure showed a further reduction in FVC and FEV1 by an average of 0.21 in a sawmill with high exposure to moulds (10 colony-forming units/m3), but not in another sawmill with ten times lower exposure. Further recordings 27 months later (Monday morning before work) displayed no further worsening in any spirometric variable. No change in lung function was noted after one day of work (Monday morning to Monday evening), but a further reduction in FVC of an average of 0.31 was seen in non-smokers at the end of the week, with apparent resolution over the weekend. The impairment was more obvious at the sawmill with higher air concentrations of organic dust than at the other sawmill. It is concluded that wood trimmers may develop restrictive pulmonary dysfunction, which might be explained by an immunopathological reaction to heavy mould exposure.

Adult↗
PubMed1986

Allergy to laboratory animals in laboratory technicians and animal keepers.

The prevalence of allergy to laboratory animals (LAA) was investigated in laboratory technicians and animal keepers. In a questionnaire 41 of 101 technicians reported symptoms provoked by work with laboratory animals. On clinical investigation 30 were found to have symptoms and signs related to contact with animals, and allergy was confirmed by radioallergosorbent tests (RAST) and skin tests in 19. All had rhinitis and 10 also had bronchial asthma. Forty seven other technicians who had stopped working with laboratory animals showed the same relative numbers of respiratory tract symptoms and of confirmed allergy to laboratory animals as did those currently handling animals. Seven of 23 animal keepers had work related symptoms. LAA symptoms were found in four and confirmed animal allergy in two. All four animal keepers with animal related symptoms had rhinitis, none had bronchial asthma. Positive animal RAST and skin tests were found only among people with animal related symptoms. A history of atopic disease was commoner among those with positive animal test results than among those with negative test results. No relation between smoking and the development of allergy to laboratory animals emerged. Simple prophylactic measures often sufficed to help technicians with animal related symptoms to remain at work.

Adult↗
PubMed1986

Standardized extracts, trees.

Sensitization to pollen from wind-pollinated trees causes significant allergy problems during springtime. The magnitude of prevalence is comparable with and, in some areas, even higher than grass pollen allergy. The symptom periods are often prolonged by cross-reactivity among species and sometimes families as well as by simultaneous sensitivity to several trees, pollinating at different times. There is a need for standardized extracts to improve diagnostic precision and treatment efficacy. A substantial amount of immunochemical data on the allergens from Betulaceae species, particularly Betula (birches), are available. Relevant methods to quantitatively and qualitatively measure the allergens of birch pollen extracts are clearly reproducible in laboratories around the world. By international collaboration, such work has generated an IS that has been accepted by the IUIS Subcommittee on Allergen Standardization. The IS is a yardstick for authorities, manufacturers, and researchers that is carefully specified in terms of 1 major and a few intermediate allergens, and also of total biologic activity by RAST inhibition. A meaningful declaration of biologic activity in vivo is awaited. As yet, only a few clinical trials have been undertaken with standardized tree pollen extracts. These are, however, highly interesting, particularly those that now have started with an oral route of administration.

Administration, Oral↗