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Biomedical subjects

S M Tarlo

Publications and source records attributed to S M Tarlo.

15 recordsLinked to original sources

Occupational asthma induced by tall oil in the rubber tyre industry.

A worker in the rubber tyre industry is described with occupational asthma from exposure to a solution of tall oil, a pine resin, confirmed by specific inhalation challenge. This supports studies of contact dermatitis which have suggested abietic and dehydroabietic acid oxidants to be the cause of colophony induced allergic reactions.

Asthma

Peak expiratory flow rates in possible occupational asthma.

Objective criteria for interpretation of peak expiratory flow rate readings were assessed in 50 patients evaluated for suspected occupational asthma who had at least two weeks of PEFR readings and an objective diagnosis based on other investigations. The prevalence of OA was 36 percent. Peak flows were interpreted by two observers blinded to other results. Criteria for a PEFR interpretation of OA were as follow: diurnal variation greater than or equal to 20 percent relatively more frequently or with greater variation on working days than days off work. With the objective diagnoses as the gold standard, the sensitivity of the PEFR interpretations was 72 percent for OA; specificity for no asthma was 53 percent. Excluding those with greater than or equal to 20 percent variation on only one day sensitivity improved to 93 percent for OA, and specificity to 77 percent. There was an acceptable level of interobserver variation (kappa 62 to 83 percent). We conclude that simple objective criteria for PEFR interpretation can be developed with acceptable interobserver variation.

Adult

Outcome of assessments for occupational asthma.

Among 154 referrals to a university hospital clinic for assessment of possible occupational asthma, the feasibility and results of different investigations were assessed using a consistent approach to all patients. A positive skin test to a workplace allergen (14 percent of all subjects), positive peak flow workplace changes (12 percent), improvement in methacholine response on holiday (9 percent), and/or positive specific challenge testing (14 percent) supported the diagnosis of occupational asthma in 61 subjects (39 percent of the total referrals). Fifty-one of these were related to a workplace sensitizer and ten to a presumed irritant. Occupational asthma was excluded in 48 subjects (31 percent) who had normal methacholine responsiveness within 24 hours of work (22 percent of the 154 subjects), peak flow readings no worse at work than on holidays (14 percent of the total referrals) and/or negative specific challenge testing (10 percent of the total referrals). Insufficient information could be obtained for a diagnosis in the remaining 45 subjects (28 percent). No single investigation was considered diagnostic in this study, as each could be positive or negative for other reasons.

Adult

Occupational asthma caused by latex in a surgical glove manufacturing plant.

A 33-year-old latex glove inspector was diagnosed as having occupational asthma on the basis of peak flow and methacholine-responsiveness changes related to workplace exposure. She had latex sensitivity by skin prick testing. This finding led to a survey of her workplace. Of the 81 workers, 84% completed a questionnaire to assess work-related respiratory symptoms, 79% underwent skin prick testing to latex and six other workplace chemicals, and 62% performed workshift spirometry. Seven workers had spirometric changes consistent with asthma, of whom five had greater than or equal to 15% fall in FEV1 during the workshift. Six of these workers underwent methacholine-challenge testing, and three were found to have a significant improvement in responsiveness to methacholine away from work, suggestive of occupational asthma. Two of these workers had positive skin test responses to latex. Including the index case, 6% of workers who had pulmonary function testing had findings of latex-related occupational asthma. Skin test responses to latex occurred in 11% of workers tested. Our findings suggest that latex should be considered among the causes of occupational asthma.

Adult

Characteristics of patients with food-related complaints.

Forty-five patients with classic food-allergic symptoms and/or subjective food-related complaints not traditionally associated with food allergy underwent evaluation. On the basis of a comprehensive clinical history, skin testing, and placebo-controlled, double-blind food challenges, patients were assigned to one of two groups: patients with reactions highly suggestive of IgE-mediated food hypersensitivity (group A, N = 22) and patients with atypical adverse food reactions that could not be confirmed by double-blind food challenge (group B, N = 23). Most patients in both groups were female, 77.3% and 91.3% of patients in group A and B, respectively. In group B, onset of symptoms occurred at an older age than in group A, 28.9 years +/- 17.2 versus 17.1 +/- 12.1 (p = 0.0015), respectively, and involved more foods, 25.6 +/- 22.1 versus 5.2 +/- 5.5 (p = 0.0002). Foods causing most prominent symptoms among patients in group A included legumes, tree nuts, crustaceans, and fish. In group B, milk, white sugar, wheat, egg, smoked/cured meat, and yeast were among the most troublesome foods. All but one patient in group A gave a positive skin test response to food; only four patients in group B had a positive response. We conclude that a subset of patients with food-related complaints can be accurately predicted to have a negative double-blind challenge with suspected foods on the basis of information obtained by history and skin testing.

Adolescent

Irritant-induced occupational asthma.

A retrospective review was performed on the files of 154 consecutive workers assessed for occupational asthma to clarify the relative frequency of asthma induced by irritants in the workplace and to determine whether such asthma was clearly distinguishable from other forms of occupational asthma. Fifty-nine workers were considered to have occupational asthma. A subset of ten had a history consistent with asthma initiated by exposure to high concentrations of an irritant, had persistent symptoms for an average of five years when seen, demonstrated increased reactivity to methacholine, and gave no prior history of pulmonary complaints. These ten had a lower incidence of atopy (20 percent vs 58 percent) and a more frequent history of smoking (80 percent vs 38 percent) than the other subjects with occupational asthma but did not differ in average latency (5.9 years vs 5.7 years). Our findings suggest that irritant-induced asthma is not uncommon, and those affected may have different baseline characteristics from others with occupational asthma.

Adult

Human sensitization to Ganoderma antigen.

Continuous air sampling with a Hirst volumetric spore trap over 3 yr has identified basidiospores of Ganoderma applanatum, a bracket fungus, as the most numerous fungal spores in two southern Ontario locations. The particle size is small and the calculated total spore mass approximates that of the spores of Cladosporium and Alternaria. Extracts of Ganoderma applanatum bracket fungus and spores in w/v, 1:10 concentration were prepared after collection of samples of the fungus from local woods. Skin prick tests with the extracts were performed in 294 consecutive children and adults attending two chest/allergy clinics. Of these patients, 182 (61.9%) reacted to 1 or more of the common inhalant allergen extracts and 24 (8.2%) reacted to Ganoderma antigen. There was no consistent relationship between reactivity to Ganoderma antigen and any of the common inhaled allergens. IgE-dependent sensitization to Ganoderma was confirmed by the radioallergosorbent test (RAST). Rabbit antisera to Ganoderma antigen preparations did not appear to cross-react with preparations of the various clinically important allergens. The findings indicate that Ganoderma antigen is commonly encountered, can induce human sensitization, and has unique antigenicity among common allergens of clinical importance.

Allergens

Nasal airway inspiratory resistance.

The relationship between transnasal pressure and nasal flow is markedly curvilinear during tidal breathing in man, and there is poor agreement among the results of various methods used to define this characteristic with a single number. We used Rohrer's equation (P = K1 V + K2 V2), where P = pressure and V = flow, and calculated values for K1 and K2 from 474 nasal inspiratory pressure/flow curves obtained from 34 human subjects by a standard method of posterior rhinometry. Nasal airway inspiratory resistance at an air flow of 0.4 liter per sec (NAIR0.4) was also calculated. Rohrer's equation was found by regression analysis to fit each curve well (0.86 less than r less than 0.9999; mean, 0.983). There was a strong correlation between NAIR0.4 and K2: NAIR 0.4 = 0.91 K2 + 0.39 (r = 0.97). Nasal congestion induced in 7 normal subjects with histamine resulted in larger changes in K2 and NAIR0.4 than K1. Patients given an intranasal corticosteroid aerosol (beclomethasone dipropionate) in a double blind crossover trial showed symptomatic improvement in nasal congestion (P less than 0.01) and significant decreases in K2 (P less than 0.02) and NAIR 0.4 (P less than 0.05), but no change in K1 (P greater than 0.2).

Adult

Beclomethasone dipropionate aerosol in perennial rhinitis.

Beclomethasone dipropionate aerosol (BDA), 50 mug four times daily sprayed into each nostril, was compared with placebo in a double-blind crossover trial in 26 patients with perennial rhinitis. Patients received BDA for 3 weeks and placebo for 3 weeks; the order of administration was randomized. Response was assessed with daily symptom score cards and twice weekly measurements of nasal airway inspiratory resistance at a standard flow rate of 0.4 L/sec. Symptom score and nasal resistance during BDA treatment were significantly lower than those duirng placebo treatment (p less than 0.02 and p less than 0.05, respectively) in the third week. Eighteen of the patients expressed a preference for BDA, 6 for placebo, and 2 for neither (p less than 0.05). Acceptable symptomatic improvement (moderate or marked) was achieved by 54%. Mild side effects were noted by 5 patients; these included nasal irritation and bleeding in 2, aerosol-induced sneezing in 2, and headache in 1. These side effects occurred in 3 patients who used BDA, 1 who used placebo, and 1 who used both. After a 6-mo follow-up period, in which the dose of BDA was adjusted and concurrent initial oral prednisone was administered to patients who were treatment failures, 73% of the patients obtained moderate or marked symptomatic improvement. No further side effects were noted during this time. Results in those in whom a possible allergic component could be identified were not different from those of the whole group. We conclude that BDA is a useful addition to the therapy of perennial rhinitis.

Administration, Intranasal

Immediate hypersensitivity to tuberculin. In vivo and in vitro studies.

Immediate responses of hypersensitivity to skin testing with purified derivative of tuberculin (PPD) were observed in 2.3 percent of 3,248 patients seen in an allergy clinic, and the relationship to delayed responses was questioned. Immediate cutaneous reactions to testing with PPD appeared in all age groups and occurred in nonatopic patients but were more common in atopic patients (p less than 0.005). Delayed cutaneous reactions to testing with PPD occurred in only three out of 76 patients with immediate reactivity. Antihistaminic suppression of immediate reactivity was not followed by evidence of delayed cutaneous reactivity. In vitro tests of lymphocytic stimulation revealed indices of stimulation with PPD to be similar both in patients with immediate and delayed cutaneous reactivity. Failure to manifest delayed cutaneous reactivity following immediate cutaneous reactions alone may be explained by antigen-antibody binding and phagocytosis, by suppressor T-lymphocytes, or by impaired release or lack of response to T-lymphocytic mediators. Adverse reactions to administration of BCG vaccine in patients with immediate cutaneous reactivity might be anticipated.

Adolescent

Effects of particulate matter exposure and medication use on asthmatics.

The health risk associated with low-level air pollution exposure is still uncertain. The association between exposure and pulmonary function was assessed with personal sampling. Small, portable multipollutant samplers were used to assess personal exposure to particulate matter. Thirty-six asthmatic subjects participated in the study for up to 20 d in both summer (n = 10 d) and winter (n = 10 d); pulmonary function was assessed at the beginning and end of each sampling day, and medication use was recorded. A within-individual longitudinal analysis of the relationship between pulmonary function and particulate matter revealed an effect of season. In winter, pulmonary function increased as particulate exposure increased, which was explained by a confounding effect of medication use. Therefore, in addition to exposure, season of the year and medication use are factors that must be considered.

Air Pollutants