PubMed Health⌕ Search

Biomedical subjects

D Talini

Publications and source records attributed to D Talini.

At least 19 recordsLinked to original sources
PubMed2002

Diagnosis of flour-induced occupational asthma in a cross-sectional study.

The diagnosis of occupational asthma is usually performed in epidemiology using a combination of symptoms and bronchial hyperresponsiveness, while in a clinical setting the 'gold standard' for the diagnosis of occupational asthma is the specific bronchial challenge test in the laboratory The aim of this study was to detect new cases of flour-induced occupational asthma (OA) in a group of workers exposed to grain and/or flour dust, by means of a step-by-step approach, as used in a clinical setting. In an epidemiological study, III millers and 186 bakers were examined by means of questionnaire, pulmonary function tests and skin-prick tests (SPT) to common allergens and to wheat flour dust extracts. From the whole sample, 82 subjects who showed asthma-like symptoms in the questionnaire and/or low forced expiratory volume in 1 sec (FEV1) were selected. Selected subjects underwent methacholine challenge test, and hyperreactive subjects underwent specific bronchial challenge with flour dust in the laboratory. Sixty-two of the selected subjects performed the methacholine challenge test, and 22 (33 8%) were hyperreactive (PD20 FEV1 <1 mg of methacholine). Fifteen of 22 hyperreactive subjects underwent specific bronchial challenge test (s BCT) with flour dust; a positive response was elicited in six subjects. These subjects can be diagnosed as having flour-induced occupational asthma. Atopy and skin sensitivity to flour was partially related to the response to flour bronchial challenge. Bronchial hyperreactivity can be observed in a small percentage of subjects with asthma-like symptoms and/or low FEV1, and a positive response to s BCTwas observed in a subgroup of hyperreactive subjects.Therefore, using these selection criteria, a diagnosis of flour-induced OA, as commonly performed in a clinical setting, can be performed in few previously undiagnosed subjects.This approach could be relevant for an early diagnosis ofoccupational asthma.

Adult↗
PubMed2001

Low molecular weight protein-tyrosine phosphatase is involved in growth inhibition during cell differentiation.

Low molecular weight protein-tyrosine phosphatase (LMW-PTP) is an enzyme involved in mitogenic signaling and cytoskeletal rearrangement after platelet-derived growth factor (PDGF) stimulation. Recently, we demonstrated that LMW-PTP is regulated by a redox mechanism involving the two cysteine residues of the catalytic site, which turn reversibly from reduced to oxidized state after PDGF stimulation. Since recent findings showed a decrease of intracellular reactive oxygen species in contact inhibited cells and a lower tyrosine phosphorylation level in dense cultures in comparison to sparse ones, we studied if the level of endogenous LMW-PTP is regulated by growth inhibition conditions, such as cell confluence and differentiation. Results show that both cell confluence and cell differentiation up-regulate LMW-PTP expression in C2C12 and PC12 cells. We demonstrate that during myogenesis LMW-PTP is regulated at translational level and that the protein accumulates at the plasma membrane. Furthermore, we showed that both myogenesis and cell-cell contact lead to a dramatic decrease of tyrosine phosphorylation level of PDGF receptor. In addition, we observed an increased association of the receptor with LMW-PTP during myogenesis. Herein, we demonstrate that myogenesis decreases the intracellular level of reactive oxygen species, as observed in dense cultures. As a consequence, LMW-PTP turns from oxidized to reduced form during muscle differentiation, increasing its activity in growth inhibition conditions such as differentiation. These data suggest that LMW-PTP plays a crucial role in physiological processes, which require cell growth arrest such as confluence and differentiation.

Animals↗
PubMed2001

Two vicinal cysteines confer a peculiar redox regulation to low molecular weight protein tyrosine phosphatase in response to platelet-derived growth factor receptor stimulation.

Low molecular weight protein tyrosine phosphatase (LMW-PTP) is an enzyme involved in platelet-derived growth factor (PDGF)-induced mitogenesis and cytoskeleton rearrangement because it is able to bind and dephosphorylate the activated receptor. LMW-PTP presents two cysteines in positions 12 and 17, both belonging to the catalytic pocket; this is a unique feature of LMW-PTP among all protein tyrosine phosphatases. Our previous results demonstrated that in vitro LMW-PTP is oxidized by either H(2)O(2) or nitric oxide with the formation of a disulfide bond between Cys-12 and Cys-17. This oxidation leads to reversible enzyme inactivation because treatment with reductants permits catalytic activity rescue. In the present study we investigated the in vivo inactivation of LMW-PTP by either extracellularly or intracellularly generated H(2)O(2), evaluating its action directly on its natural substrate, PDGF receptor. LMW-PTP is oxidized and inactivated by exogenous oxidative stress and recovers its activity after oxidant removal. LMW-PTP is oxidized also during PDGF signaling, very likely upon PDGF-induced H(2)O(2) production, and recovers its activity within 40 min. Our results strongly suggest that reversibility of in vivo LMW-PTP oxidation is glutathione-dependent. In addition, we propose an intriguing and peculiar role of Cys-17 in the formation of a S-S intramolecular bond, which protects the catalytic Cys-12 from further and irreversible oxidation. On the basis of our results we propose that the presence of an additional cysteine near the catalytic cysteine could confer to LMW-PTP the ability to rapidly recover its activity and finely regulate PDGF receptor activation during both extracellularly and intracellularly generated oxidative stress.

3T3 Cells↗
PubMed2000

Low molecular weight protein-tyrosine phosphatase controls the rate and the strength of NIH-3T3 cells adhesion through its phosphorylation on tyrosine 131 or 132.

The low molecular weight protein-tyrosine phosphatase (LMW-PTP) is an enzyme involved in platelet-derived growth factor (PDGF)-induced mitogenesis and cytoskeleton rearrangement. Our previous results demonstrated that LMW-PTP is able to bind and dephosphorylate activated PDGF receptor, thus inhibiting cell proliferation. Recently we have shown that LMW-PTP is specifically phosphorylated by c-Src in a cytoskeleton-associated fraction in response to PDGF, and this phosphorylation increases LMW-PTP activity about 20-fold. LMW-PTP strongly influences cell adhesion, spreading, and chemotaxis induced by PDGF stimulation, by regulating the phosphorylation level of p190Rho-GAP, a protein that is able to regulate Rho activity and hence cytoskeleton rearrangement. In the present study we investigate the physiological role of the two LMW-PTP tyrosine phosphorylation sites, using LMW-PTP mutants on tyrosine 131 or 132. We demonstrate that each tyrosine residue is involved in specific LMW-PTP functions. Both of them are phosphorylated during PDGF signaling. Phosphorylation on tyrosine 131 influences mitogenesis, dephosphorylating activated PDGF-R and cytoskeleton rearrangement, acting on p190RhoGAP. Phosphorylation on tyrosine 132 leads to an increase in the strength of cell substrate adhesion, down-regulating matrix metalloproteases expression, through the inhibition of Grb2/MAPK pathway. In conclusion, LMW-PTP tyrosine phosphorylation on both Tyr(131) or Tyr(132) cooperate to determine a faster and stronger adhesion to extracellular matrix, although these two events may diverge in timing and relative amount.

3T3 Cells↗
PubMed2000

LMW-PTP exerts a differential regulation on PDGF- and insulin-mediated signaling.

Low-molecular-weight protein tyrosine phosphatase (LMW-PTP) is able to specifically bind and dephosphorylate activated PDGF and insulin receptors, modulating the onset of mitogenic process. LMW-PTP is present in two distinct intracellular locations. While the cytosolic LMW-PTP pool interacts directly with activated insulin or PDGF receptors, the cytoskeleton-associated LMW-PTP is tyrosine phosphorylated upon PDGF stimulation and is involved in cytoskeleton rearrangement acting on p190Rho-GAP. We investigated the differential role of LMW-PTP in PDGF- or insulin-induced mitogenesis and cytoskeleton rearrangement. Dominant negative LMW-PTP influences both PDGF- and insulin-induced mitogenesis with a different extent and it induces a decrease in cellular adhesion and chemotaxis after PDGF but not insulin treatment. PDGF but not insulin stimulation leads to tyrosine phosphorylation of LMW-PTP. We propose that the differential effect of LMW-PTP on PDGF and insulin signaling is mainly due to the fact that during insulin signaling LMW-PTP does not become phosphorylated and thus does not act on its cytoskeleton-associated substrate/s.

Animals↗
PubMed1999

Specific inhalation challenge with wheat flour in workers with suspected baker's asthma.

OBJECTIVE: The aim of this study was to evaluate the outcome of the specific inhalation challenge test (SIC) in 160 subjects with suspected baker's asthma and to assess its relation to total flour dust levels and to personal characteristics such as specific skin sensitisation, non-specific bronchial hyper-responsiveness (NSBH) and atopy. METHODS: We investigated the outcome of SIC tests performed with wheat flour in six Italian laboratories. For each subject, data was available regarding skin sensitisation to wheat flour, NSBH, atopy, forced expiratory volume at 1 s (FEV1) monitoring and airborne flour dust in the challenge chamber measured by the gravimetric method (total dust in mg/m(3)). RESULTS: The SIC test was positive for early asthma in 42 subjects (26%) and for late/dual asthma in 18 (11%). Positive outcome to SIC was significantly associated with NBSH (odds ratio, OR: 3.5, 95% CI: 1. 6-7.7) and skin sensitisation to wheat flour (OR: 3.1, 95% CI: 1.3-7. 0). Exposure level to wheat flour was less than or equal to 10 mg/m(3 )in 12% of individuals, ranged between 11 and 30 mg/m(3) in 43% and exceeded 30 mg/m(3) in 45%. The outcome of SIC was always negative among workers not skin sensitised to wheat flour and without NSBH and atopy. An increasing prevalence of positive SIC was observed among workers with one or more of the above-mentioned personal characteristics whose challenge exposure was greater than 10 mg/m(3) (P < 0.001). CONCLUSION: Procedures currently adopted for wheat flour dust exposure during SIC need to be better standardised in order to avoid excessive airborne dust exposure. Over-exposure seems to be of no use for the diagnosis and risks making the asthmatic reaction worse, particularly in patients who are both sensitised to wheat allergens and have NSBH and/or atopy.

Asthma↗
PubMed1999

Dyspnoea is associated with pulmonary function impairment in exposed workers.

This study aimed to evaluate the prevalence of dysponea and its predictors in studies on several working male groups in British Columbia (BC), Canada (cedar sawmill, grain elevator, pulpmill, and aluminum smelter workers), and Tuscany (T), Italy, (shoe and furniture makers, millers, bakers, and pharmaceutical workers). We performed cross-sectional health studies (interviews and pulmonary function tests) for 2498 BC and 1474 T workers exposed to air contaminants, and 1110 BC and 243 T controls. Similar questionnaires and the same definitions were used in BC and in T. Pulmonary function tests were also performed. The participation rates were >92% in BC workers and 82% in T workers. The overall prevalence of moderate dyspnoea was not different in exposed BC and T workers in comparison with controls. Slight dyspnoea was significantly more frequent in BC workers, but not in T workers, with respect to controls. After adjusting for age, body mass index (BMI), smoking, current asthma, and chronic bronchitis, forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were found to be significantly associated with slight and moderate dyspnoea in BC workers, and slight dyspnoea in T workers. Isolated dyspnoea is associated with reduction in FEV1 and FVC in working populations, after adjusting for potentially confounding variables.

Adult↗
PubMed1998

Asthma-like symptoms, atopy, and bronchial responsiveness in furniture workers.

OBJECTIVES: To study the role of individual and occupational risk factors for asthma in furniture workers. METHODS: 296 workers were examined (258 men, 38 women) with a questionnaire of respiratory symptoms and diseases, baseline spirometry, bronchial provocative test with methacholine, and skin prick tests. Non-specific bronchial hyperreactivity was defined as when a provocative dose with a fall of 20% in forced expiratory volume in 1 second (PD20FEV1) was < 0.8 mg and atopy in the presence of at least one positive response to skin prick tests. Workers were subdivided into spray painters (exposed to low concentrations of diisocyanates and solvents), woodworkers (exposed to wood dusts), and assemblers (control group). RESULTS: The prevalences of attacks of shortness of breath with wheezing and dyspnoea were higher in spray painters (13.5% and 11.5% respectively) than in woodworkers (7.7% and 6.3%) or in assemblers (1.6% and 1.6%); prevalences of chronic cough, asthma, and rhinitis were also slightly but not significantly higher in spray painters and in woodworkers than in assemblers. The difference in the prevalence of respiratory symptoms among the job titles was due to the atopic subjects, who showed a higher prevalence of chronic cough, wheeze, shortness of breath with wheeze, dyspnoea, and asthma in spray painters than in the other groups. The prevalence of non-specific bronchial hyperreactivity in subjects who performed bronchial provocative tests was 17.7%, with no significant difference among groups. Asthma symptoms were significantly associated with non-specific bronchial hyperreactivity. Asthma-like symptoms plus non-specific bronchial hyperreactivity was found in 4% of assemblers, 10% of woodworkers, and 13.3% of spray painters (chi 2 = 2.6, NS). Multiple logistic analysis taking into account individual (smoke, atopy, age) and occupational (job titles) risk factors confirmed that spray painters had higher prevalence of chronic cough than assemblers, and a trend in increasing the prevalence of shortness of breath with wheeze, dyspnoea, and asthma. CONCLUSIONS: Painters in the furniture industry, particularly atopic subjects, are at higher risk of asthma-like symptoms than other job titles. In these workers asthma-like symptoms are more sensitive than non-specific bronchial hyperreactivity in detecting a negative effect of the occupational exposure.

Adult↗
PubMed1995

Chest radiography and high resolution computed tomography in the evaluation of workers exposed to silica dust: relation with functional findings.

OBJECTIVES: To compare the usefulness of high resolution computed tomography (HRCT) with chest radiography (CR) in the diagnosis and assessment of severity of silicosis. METHODS: 27 workers exposed to silica underwent CR, HRCT, and pulmonary function tests. Two experienced readers independently evaluated CR by International Labour Office classification, and grouped the results into four categories. HRCT categories of nodule profusion and the extent of emphysema were graded on a four point scale; in 20 subjects the percentage distribution of lung densities were measured by HRCT. RESULTS: Concordance between readers was higher for HRCT than for CR (K statistic = 0.49 and 0.29 respectively). There was poor concordance between CR and HRCT in the early stage of silicosis. No significant difference in pulmonary function tests was found among different CR categories, but forced expiratory volume in one second (FEV1), maximal expiratory flow at 50% and 75% of FVC (MEF50, MEF75), and diffusion capacity significantly decreased with increasing HRCT categories. Subjects with simple silicosis detected by HRCT had a lower FEV1 than subjects without silicosis, whereas subjects with conglomerated silicosis showed higher residual volume and functional residual capacity than subjects with simple silicosis. These relations were not affected by smoking or symptoms of chronic bronchitis. Different grades of emphysema detected by HRCT were significantly different in diffusion capacity. Only the HRCTs of the lowest and the highest categories of profusion of parenchymal opacities were significantly different in their distribution of density classes. CONCLUSION: HRCT is more reproducible and accurate than CR, as suggested by the higher agreement between readers and the better correlation with pulmonary function tests, irrespective of smoking and chronic bronchitis; however, these data do not support the hypothesis that HRCT is more sensitive than CR in the early detection of silicosis.

Adult↗
PubMed1995

[High-resolution computed tomography compared with the thoracic radiogram and respiratory function tests in assessing workers exposed to silica].

To compare the usefulness of high-resolution computed tomography (HRCT) and chest radiography in the functional evaluation of silica-exposed workers, 27 workers were submitted to posteroanterior and lateral chest radiographs, apex to base HRCT scans and pulmonary function tests. Two experienced readers studied plain films independently to assess small opacities profusion (ILO-UC, Geneva 1980): from 0/- to 3/+. HRCT grading and extent of silicotic nodules and associated emphysema were scored on a four-point scale. Inter-reader analysis showed better agreement for HRCT (K = 0.49) than chest radiography (K = 0.29). Poor agreement was observed between chest radiography and HRCT classes, particularly in the early stages of silicosis. No correlation was observed between chest radiography score and pulmonary function tests, while a significant correlation was observed between HRCT classes (grade and extent of the nodules) and FEV1, MEF50, MEF75, RV and FRC. In conclusion, HRCT exhibited better reproducibility and higher accuracy than chest radiography in identifying the absence of silicotic nodules and in depicting functionally important lesions. To this purpose, HRCT can be considered a useful support to conventional chest radiography.

Aged↗
PubMed1991

Salbutamol plus beclomethasone dipropionate, but not salbutamol alone, completely prevent early and late asthmatic responses to allergen.

The effect of a week treatment with inhaled salbutamol plus placebo (S+P) vs. salbutamol combined with beclomethasone dipropionate (S+BDP) on early and late asthmatic responses to inhaled allergen was studied in ten atopic patients in a randomized, double-blind, cross-over study. All patients had previously shown a dual type response to the specific bronchial provocative test (sBPT). Each patient performed two periods of treatment for a week, with a 15 day interval between them: (a) salbutamol 0.3 mg, tid + placebo; (b) salbutamol 0.3 mg+BDP 0.2 mg, tid; at the end of each treatment period, sBPT was performed and the last treatments were given 1.5-2 h before and 3-4 h after allergen challenge. S + BDP completely prevented both early and late responses to allergen, while S + P reduced but did not completely inhibit early and late responses. The difference between the two treatments was significant for early and late asthmatic responses. Non-specific bronchial hyperresponsiveness to methacholine was performed before each treatment period, after 6 days of treatment before sBPT and the day after sBPT at the end of the treatment period; there was only a mild increase in PD15FEV1 methacholine after 6 days of treatment with S + BDP in comparison with S + P treatment. These results suggest that salbutamol plus beclomethasone may be used effectively in the prophylaxis of early and late asthmatic reactions induced by allergen in sensitized subjects.

Adolescent↗
PubMed1990

Pattern of airway response to allergen extract of Phleum pratensis in asthmatic patients during and outside the pollen season.

In order to evaluate the pattern of airway response to a specific bronchial provocative test (sBPT) with an extract of Phleum pratensis standardized in biological units (BU), we studied 27 patients with seasonal asthma due to grass pollen by means of allergologic evaluations, methacholine inhalation test and sBPT, outside the pollen season in all patients and, in 10 of them, also during the pollen season. We used a DeVilbiss 646 nebulizer with a dosimeter, giving increasing doses (0.01-2.5 BU) of the allergen solution and we monitored FEV1 to assess early (EAR) and late (LAR) airway responses. Outside the pollen season sBPT elicited an isolated EAR in 16 and a dual asthmatic response (DAR) in 11 patients. We observed no significant difference between EAR and DAR patients as regards the provocative dose causing a 15% fall in FEV1 (PD15FEV1) methacholine, EAR (expressed by PD15FEV1 allergen) or allergologic data. There was a significant relationship between PD15FEV1 allergen and PD15FEV1 methacholine (r = 0.43, p less than 0.05). The reproducibility of sBPT was assessed in 11 patients outside the pollen season. The correlation coefficients between the two tests were: r = 0.91, p less than 0.001 for the total delivered dose of allergen during sBPT; r = 0.79, p less than 0.01 for PD15FEV1 allergen; r = 0.95, p less than 0.001 for the maximum percent fall in FEV1 during LAR. Ten patients repeated all tests during the grass pollen season. PD15FEV1 methacholine and baseline FEV1 decreased significantly during the pollen season, but PD15FEV1 allergen did not change significantly during the season.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Bronchoalveolar lavage and morphology of the airways after cessation of exposure in asthmatic subjects sensitized to toluene diisocyanate.

To evaluate the morphologic basis of the different outcomes of toluene diisocyanate (TDI) asthma after quitting occupational exposure, we examined ten patients with TDI asthma who showed, at diagnosis, a positive TDI challenge test and nonspecific bronchial hyperresponsiveness (NSBH) to methacholine. After diagnosis, all patients ceased work and a 4- to 40-month follow-up was obtained with three to eight determinations of the cumulative dose producing a 15 percent fall in FEV1 (PD15FEV1) methacholine in each patient. Bronchoalveolar lavage (BAL) and biopsy of bronchial muscosa were performed 3 to 39 months after cessation of work, in the absence of acute exacerbations of the disease. Total cell count in BAL fluid was moderately increased in four of ten patients, eosinophils were increased in five of ten patients, and neutrophils were increased in eight of ten patients. Mucosal biopsy specimens of main or lobar bronchi were available in eight of ten patients; epithelial damage and thickening of basement membrane was observed in almost all patients, as well as a mild-to-moderate inflammatory reaction in the submucosa, mainly represented by lymphocytes, eosinophils, and neutrophils. No relationship was observed between the cellularity of BAL and the degree of NSBH at the time of BAL; mean values of total cells and differential count were not different between patients with presence or absence of the different histologic findings. Mucosal biopsy and BAL were performed also in four subjects exposed to dusts without respiratory symptoms or NSBH; similar findings were obtained except for the absence of eosinophils in BAL and a lesser degree of basement membrane thickening and inflammatory reaction in the submucosa. The study of the changes in NSBH after quitting exposure showed that five of ten patients had a significant improvement in NSBH to methacholine, as evaluated by a positive significant linear regression between months of work cessation and PD15FEV1 methacholine; only one of these five patients had an increased number of eosinophils in BAL fluid. By contrast, four of the five patients with persistent NSBH after quitting exposure had an increased number of eosinophils in BAL. We suggest that persistent NSBH in TDI asthma after cessation of work may be related to an inflammatory reaction in which eosinophil infiltration seems to be a major determinant.

Adult↗
PubMed1989

Vagal reflexes and asthma.

Although vagal reflexes are well documented in animal models of airway hyperresponsiveness, their importance in asthmatic attacks in man is less documented. Indeed most of the stimuli that can trigger bronchoconstriction act only partially through a cholinergic reflex. However, inflammatory mediators released in airways during asthma attacks may stimulate different sites of cholinergic pathways, i.e. in the sensory receptors, afferent, efferent, ganglionic or postganglionic sites. Further studies are required to assess the real influence of chemical mediators on vagal activity in asthmatic subjects during spontaneous or induced bronchoconstriction.

Animals↗
PubMed1987

Atropine does not inhibit late asthmatic responses induced by toluene-diisocyanate in sensitized subjects.

To determine whether early and/or late asthmatic responses induced by toluene diisocyanate (TDI) are caused by a reflex mechanism involving stimulation of muscarinic receptors, we studied the effect of the muscarinic antagonist atropine on early and late airway response induced by TDI. A preliminary study was conducted in asthmatics to assess whether the selected dose of atropine provided adequate muscarinic blockade. On different days we measured the provocation dose (in milligrams) of carbachol causing a 15% decrease in FEV1 (PD15FEV1) without and with atropine premedication (0.008 or 0.012 mg/kg subcutaneous atropine 30 or 90 min before carbachol challenge test). We found that 0.008 to 0.012 mg/kg subcutaneous atropine increased the PD15FEV1 carbachol by 6- to 10-fold, inducing a consistent and prolonged decrease in nonspecific bronchial hyperresponsiveness to cholinergic agent. Then we examined 10 subjects with a history of sensitization to TDI in 2 sets of experiments. In the first set of experiments, we studied the subjects before and after exposure to TDI (0.04 ppm; 30 min) after no treatment. In the second set of experiments, carried out 1 to 2 wk later, we repeated the same procedure after treatment with atropine (0.008 to 0.012 mg/kg atropine sulfate administered subcutaneously 30 min before TDI challenge, and then at 90-min intervals after TDI exposure); all patients showed symptoms of atropine effect (dryness of mouth, cycloplegia, increased heart rate).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1986

Skin reactivity and specific IgE levels in the evaluation of allergic sensitivity to common allergens for epidemiological purposes.

An investigation was conducted to test the validity of the skin-prick test (SPT) with eleven common allergens (Lofarma series proposed by Italian National Research Council for epidemiological studies) as a method for predicting the presence of specific antibodies in serum. The relationship between SPT, evaluated by two different methods (MWD = mean weal diameter, AHWR = allergen histamine weal ratio), and specific IgE levels (RAST) has been investigated in 101 patients tested consecutively for suspected allergic disease. Sensitivity, specificity and overall efficiency were assessed for different criteria of SPT positivity (greater than or equal to 4 mm or greater than or equal to 5 mm using MWD; ++ or using AHWR). For pollens and moulds, a weal diameter greater than or equal to 5 mm gave better results than 4 mm, whereas for mites a MWD greater than or equal to 4 mm showed a better sensitivity and overall efficiency than 5 mm. Danders showed low sensitivity when either 5 or 4 mm criterion was considered. AHWR evaluation gave no better results, except for animal danders. Correlation coefficients between weal size and RAST class showed a good relationship for mites and pollens using both methods of SPT evaluation; a moderate relationship was observed with MWD criterion for moulds and with AHWR for danders. We conclude that a weal diameter greater than or equal to 5 mm can be assumed to to predict RAST positivity for pollens and moulds, and for mites, a weal greater than or equal to 4 mm can be a more accurate criterion.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1986

Specific bronchial reactivity to toluene diisocyanate: relationship with baseline clinical findings.

One hundred and fourteen subjects with asthma induced by toluene diisocyanate were identified and the pattern of their bronchial responses to challenge with toluene diisocyanate was studied. An occupational type specific bronchial provocation test with toluene diisocyanate (10-25 parts per thousand million for 10-15 minutes) elicited an immediate response in 24, a late response in 50, and a dual response in 40 patients. Subjects with a dual response showed at diagnosis a longer duration of symptoms and a greater prevalence of airway obstruction; in these subjects FEV1 (percentage of predicted value) was lower than in subjects with immediate or late reactions to toluene diisocyanate. The percentage of current smokers and ex-smokers was significantly lower in subjects with a late response (26%) than in subjects with immediate or dual responses (56% and 57% respectively). In 27 of the 114 subjects a non-specific challenge test with methacholine was performed and subjects with dual responses showed greater non-specific bronchial hyperresponsiveness than the other groups. These results suggest that a dual response to specific challenge in bronchial asthma related to toluene diisocyanate may be associated with more severe disease than other types of response, as assessed by duration of symptoms, baseline airway obstruction, and non-specific bronchial hyperresponsiveness. The high prevalence of non-smokers and low prevalence of smokers in the group with a late response to specific challenge is so far unexplained.

Adult↗