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In the tumor microenvironment, Cancer Associated Fibroblasts (CAFs) become activated by cancer cells and increase their secretory activity to produce soluble factors that contribute to tumor cells proliferation, invasion and dissemination to distant organs. The pro-tumorigenic transcription factor STAT3 and its canonical inducer, the pro-inflammatory cytokine IL-6, act conjunctly in a positive feedback loop that maintains high levels of IL-6 secretion and STAT3 activation in both tumor and stromal cells. Here, we demonstrate that STAT3 is essential for the pro-tumorigenic functions of murine breast cancer CAFs both in vitro and in vivo, and identify a STAT3 signature significantly enriched for genes encoding for secreted proteins. Among these, ANGPTL4, MMP13 and STC-1 were functionally validated as STAT3-dependent mediators of CAF pro-tumorigenic functions by different approaches. Both in vitro and in vivo CAFs activities were moreover impaired by MMP13 inhibition, supporting the feasibility of a therapeutic approach based on inhibiting STAT3-induced CAF-secreted proteins. The clinical potential of such an approach is supported by the observation that an equivalent CAF-STAT3 signature in humans is expressed at high levels in breast cancer stromal cells and characterizes patients with a shorter disease specific survival, including those with basal-like disease., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Transcriptome data provide a valuable resource for the study of cancer molecular mechanisms, but technical biases, sample heterogeneity, and small sample sizes result in poorly reproducible lists of regulated genes. Additionally, the presence of multiple cellular components contributing to cancer development complicates the interpretation of bulk transcriptomic profiles. To address these issues, we collected 48 microarray datasets derived from laser capture microdissected stroma or epithelium in breast tumors and performed a meta-analysis identifying robust lists of differentially expressed genes. This was used to create a database with carefully harmonized metadata that we make freely available to the research community. As predicted, combining the results of multiple datasets improved statistical power. Moreover, the separate analysis of stroma and epithelium allowed the identification of genes with different contributions in each compartment, which would not be detected by bulk analysis due to their distinct regulation in the two compartments. Our method can be profitably used to help in the discovery of biomarkers and the identification of functionally relevant genes in both the stroma and the epithelium. This database was made to be readily accessible through a user-friendly web interface.

The tango brings out the true essence of the individuals, it removes every mask and stops the lies you tells yourself, forcingthe contact with yourself even before with the others. This is the essence on which we relied to propose a course of psychotherapy with basic elements of tango, as a peculiar mode of experiencing oneself. In this paper we analyze how Tango could become an interesting instrument for the cure and the prevention of psychological and physical problems.

Background: Italian law requires an extensive health surveillance of workers after cessation of their employment status in the case of occupational exposure to carcinogens, including asbestos. Nonetheless, Italian law does not specify the timeframe of these clinical checks, nor who has financial and organizational responsibility for this surveillance. A literature search confirmed a lack of consensus around the objectives and methods to follow up workers with past occupational exposure to asbestos., Objectives: To develop an updated evidence-based methodology for an appropriate health surveillance programme., Methods: We present an overview of the field experience developed by the Veneto Region from 2000 to 2011, and new studies that could contribute to establishing a national policy for the medical surveillance of workers with past asbestos exposure., Results: There were three specific topics: (1) definition of a reliable method to identify asbestos workers (through multiple sources and procedures that meet current confidentiality regulations); (2) detection of asbestos fibres in biological media (to support the etiological diagnosis of asbestos-related diseases); (3) creation of a national protocol of health surveillance (through the assessment of policies developed by other Regions in this field, and recruiting from these regions a cohort of past-exposed workers: the epidemiological study should offer relevant suggestions for specific surveillance approaches, based on either estimated cumulative asbestos exposure or detection of x-ray patterns of pleural plaques and/or asbestosis)., Conclusions: These studies will support the Regions in setting up health care policies directed at workers with past asbestos exposure.

Background and Objectives: Health impairment due to alcohol use and abuse is well known, in terms of relationship with traffic accidents and work accidents. In Italy almost 10 per cent of accidents at work involve intoxicated people injuring themselves and innocent victims. Alcohol abuse is a factor involved in determining severe accidents in the construction industry and epidemiological studies demonstrated a relationship between an elevated alcohol use and severity of accidents. Since in the Province of Belluno alcohol consumption may be elevated also at work, the two Occupational Health Units (SPISAL) in the province organized a campaign of information and surveillance against alcohol consumption at work in the construction industry. This report shows the campaign results, mainly in terms of breath alcohol tests performed in construction workers., Discussion and Conclusions: After an extensive information campaign we inspected 50 sites, where 105 construction companies were at work, and tested 294 workers by breath alcohol test. No-one refused the test. Only 2.7% construction workers were positive for the breath alcohol test, and the levels were not elevated. This study shows that the construction workers in Belluno Province are responsible drinkers and are well aware of the policy of prohibition of alcohol consumption at work.

Young people who start smoking are constantly increasing and the age of initiation has decreased. This work presents the results of a specific health education programme on smoking that was carried out for a group of 804 young apprentices who came to the Occupational Health Units in Belluno for a check on work fitness. The objective is to induce young non-smoking apprentices to continue as such and smokers to give up smoking. After two years, a telephone follow-up was carried out to see if the smoking habit has changed. The average age of the group was 19 years and the percentage of smokers was 34%; after two years the percentage of smokers was 29.5%. Then, the percentage of smokers has fallen and the percentage of ex smokers has increased, because smokers became non-smokers during the period of observation. This results show the effectiveness of health programme on smoking directed to young apprentices already demonstrated by a previous study and confirm the withdraw rates obtained by counselling methods. Moreover, this study stressed the role of Occupational Health Units in prevention programmes addressed to the young apprentices during work fitness check.

Objectives: To report the occurrence of mesotheliomas in Italy among subjects who worked, when migrant, at a cement-asbestos factory in Niederurnen, Switzerland, and had resettled to the home country., Methods: Information about the disease and on the working history of subjects was collected by regional mesothelioma registries. Only cases diagnosed by means of histo-pathological examinations have been considered here., Results: 15 mesotheliomas (13 pleural, 2 perithoneal; 12 among males, 3 among females) have been identified among Italians, who had worked at the factory. None of them had other occupational exposure to asbestos. The majority was living in the Veneto Region (North East of Italy), and in Puglia (Southern Italy)., Conclusions: Exposure to asbestos at this factory has already caused an important number of occupational cancers among the employees, a large fraction being constituted of migrants. In order to avoid under-estimation of risks and to allow compensation, diseases which occur among foreign workers returned to their home country should be evaluated. Migration for work is at the genesis of asbestos-related mesotheliomas now occurring in Italy.

Background: Polymorphism at the pi class glutathione-S-transferase locus (GSTP1) is associated with allergen-induced asthma and related phenotypes., Objective: We sought to determine whether GSTP1 polymorphism influences susceptibility to asthma induced by toluene diisocyanate (TDI)., Methods: The role of GSTP1 was assessed in 131 workers exposed to TDI, 92 with TDI-induced asthma and 39 asymptomatic subjects. The phenotype of the disease was characterized by using detailed clinical history, lung volumes, airway responsiveness to methacholine, and airway responsiveness to TDI. GST genotypes were determined by using PCR-based assays., Results: In patients exposed to TDI for 10 or more years, the frequency of the GSTP1 Val/Val genotype was lower in subjects who had asthma (odds ratio, 0.23; 95% confidence interval, 0.05-1.13; P =.074). Similarly, the frequency of this genotype was significantly lower in subjects with evidence of moderate-to-severe airway hyperresponsiveness to methacholine compared with the frequency in subjects with normal or mild hyperresponsiveness (P =.033)., Conclusion: These data suggest that homozygosity for the GSTP1*Val allele confers protection against TDI-induced asthma and airway hyperresponsiveness. This view is supported by the finding that the protective effect increases in proportion to the duration of exposure to TDI.

The present study was designed to evaluate whether pre-incubation with serum, obtained from both control and toluene diisocyanate (TDI)-immunized guinea-pigs, modified the contractile response to TDI in isolated guinea-pig bronchial rings. Guinea-pigs were anaesthetized and the main bronchi dissected in two rings. Bronchial rings were incubated with normal or immune serum (100 microl ml(-1) for 2 h) and dose-response curves to TDI (0.03-1000 microM) were studied isometrically. Before serum incubation, in eight bronchial rings, epithelium was removed by rubbing the luminal surface gently with a gauze. In control rings, TDI produced a concentration-dependent contraction, whereas in rings pre-incubated with either normal or TDI-immune serum, it produced a concentration-dependent relaxation. Relaxation was 101.4 (SEM 17.4)% and 94.9 (SEM 21)% of the relaxation induced by isoproterenol (1 mM) respectively with normal and TDI-immune serum. Similarly to the pre-incubation with serum, pre-incubation with albumin produced a concentration-dependent relaxation to TDI. Serum-induced relaxant response to TDI was not affected by capsaicin desensitization, it was only partially inhibited by an NK1-tachykinin antagonist, whereas it was blocked by indomethacin. In bronchial rings without epithelium, pre-incubated with serum, TDI caused contraction at highest doses, while it still induced relaxation at the lowest doses. This study shows that one or more components of the serum modify the contractile response to TDI in isolated guinea-pig bronchi. In bronchial rings without epithelium serum was able to inhibit the contration induced by low doses of TDI.

Objectives: Guinea pigs were used to determine whether immunization and challenge by toluene diisocyanate (TDI) induce changes in the serum protein concentrations of the "acute-phase response" and whether TDI can form adducts with serum proteins., Methods: Guinea pigs were immunized by weekly intradermal injections of TDI and challenged with TDI 7 days after the 3rd injection. The animals were killed 6 hours after the challenge, and serum was analyzed for protein characterization by gel electrophoresis and for specific antibodies to TDI by enzyme-linked immunosorbent assay (ELISA) and Western blotting., Results: The total serum protein concentration of the immunized TDI-challenged guinea pigs increased in comparison with that of nonimmunized animals [75 (SE 0.7) versus 47.4 (SE 2.3) mg/ml; ]. Albumin and alpha, and alpha2 globulins increased significantly [respectively: 65.8 (SE 0.2)%, 2.1 (SE 0.1)% and 7.2 (SE 0.1)% versus 59 (SE 1.3)%, 1.3 (SE 0.1)% and 3.7 (SE 0.1)%], whereas beta1 and beta2 globulins decreased in the immunized TDI-challenged guinea pigs [7.8 (SE 0.2)% and 0.8 (SE 0.2)% versus 15.8 (SE 0.7)% and 4.8 (SE 0.2)%]. The gamma globulin concentrations did not change significantly. In the immunized TDI-challenged animals, albumin was modified by TDI and ran faster on agarose gel electrophoresis than did albumin from nonimmunized guinea pigs. In the ELISA, only immunized animals had high titers of TDI-specific antibodies (IgG and IgG1); by blotting, the antibodies reacted against TDI, the TDI-BSA-conjugate and several TDI-conjugated guinea pig serum proteins, but they did not react against any native or denaturated serum protein when unconjugated with TDI., Conclusions: These findings indicate that, in guinea pigs, immunization and challenge with TDI induces changes in serum proteins of the "acute phase response" and TDI is adducted to serum proteins with different molecular weights (eg, albumin).

We investigated the effect of 5 months of treatment with inhaled beclomethasone dipropionate (BDP) on the airway responsiveness to methacholine (PD20 FEV1) and to toluene diisocyanate (TDI) in 15 sensitized asthmatic subjects who had been removed from occupational exposure to TDI. After the diagnosis was established by a positive inhalation challenge with TDI, each subject was removed from occupational exposure to isocyanates and treated with either BDP (1 mg twice per day, n = 7) or placebo (n = 8) for 5 months. The study was double blind for parallel groups. P20 FEV1 methacholine was measured before and three times during treatment and then at 6 months, that is, 4 wk after cessation of treatment. Airway sensitivity to TDI was assessed with specific inhalation challenge before treatment and at 6 months. Beclomethasone reduced the airway hyperresponsiveness to methacholine but did not affect the response to TDI. In fact, in the subjects on BDP, P20 FEV1 increased from 0.145 to 0.485 mg (p < 0.05) after 2 months of treatment. A further increase was observed at 4 and 5 months (0.548 and 0.629 mg, respectively, p < 0.01), and the improvement in nonspecific airway responsiveness was maintained after a 1-month washout period (0.637 mg, p < 0.01). In contrast, in the subjects on placebo, P20 FEV1 did not change significantly. At the end of the study, the severity of asthmatic reactions induced by bronchial challenge with TDI was significantly reduced in both groups, but no differences were observed between placebo and BDP.(ABSTRACT TRUNCATED AT 250 WORDS)

Toluene diisocyanate (TDI)-induced asthma is a frequent occupational airway disease. To determine whether a calibrated dosage of oral slow-release theophylline inhibits asthmatic reactions and the associated increase of airway responsiveness to methacholine induced by TDI, we examined six asthmatic subjects who developed a late or a dual asthmatic reaction after TDI inhalation challenge. We administered oral slow-release theophylline or placebo to each subject for 7 days according to a double-blind, randomized, cross-over study design. When the subjects received a placebo, TDI caused a late or a dual asthmatic reaction. When the subjects received theophylline. TDI caused significantly reduced late asthmatic reactions. Mean serum theophylline concentrations were within the therapeutic range. Theophylline neither modified the baseline airway responsiveness to methacholine, nor the increase of airway responsiveness to methacholine induced by TDI. These results suggest that slow-release theophylline may improve TDI-induced late asthmatic reactions, but it does not change the baseline airway responsiveness to methacholine and the increase of airway responsiveness to methacholine induced by TDI.

We examined the light and electron microscopic structure of lobar bronchial biopsies of nine subjects with occupational asthma induced by toluene diisocyanate (TDI) and of four control nonasthmatic subjects who had never been exposed to TDI. Inflammatory cell numbers were separately assessed in the intact epithelium, in the more superficial layer of the submucosa, and in the total submucosa. Asthmatic subjects had an increased number of inflammatory cells in the airway mucosa compared with control subjects. Eosinophils were significantly increased in all compartments, CD45-positive cells were significantly increased in the epithelium and in the more superficial layer of the submucosa, and mast cells were significantly increased only in epithelium. By electron microscopy eosinophils and mast cells appeared degranulated only in asthmatic patients. In the areas of epithelium that appeared intact by light microscopy, electron microscopy showed that, although the intercellular spaces between columnar cells were similar in asthmatic and control groups, the intercellular spaces between basal cells were significantly wider in patients with asthma. Patients with TDI-induced asthma also had a thicker subepithelial reticular layer, where immunohistochemistry showed the presence of collagen III. In conclusion, in patients with asthma induced by TDI, the airway mucosa shows pathologic features, such as inflammatory cell infiltrate and thickening of subepithelial collagen, similar to those described in atopic asthma.

To determine whether treatment with aerosolized dexamethasone isonicotinate inhibits asthmatic reactions and the associated increase in airway responsiveness induced by toluene diisocyanate (TDI), we studied six sensitized subjects with previously demonstrated dual or late asthmatic reaction after inhalation challenge with TDI. Dexamethasone isonicotinate (four puffs bid for seven days, ie, 0.5 mg bid for seven days; last four puffs 30 minutes before TDI) was administered for seven days before the inhalation challenge with TDI (0.010 to 0.015 ppm for 10 to 30 minutes) to each subject, according to a single-blind study design. When the subjects received no treatment, FEV1 markedly decreased and airway responsiveness increased after exposure to TDI. By contrast, when the subjects were treated with dexamethasone-isonicotinate, FEV1 decreased significantly less, but airway responsiveness still significantly increased after exposure to TDI. These results suggest that aerosolized dexamethasone isonicotinate may be used in the prophylaxis of TDI-induced late asthmatic reactions.

The contractile properties of muscle cells are related to the molecular structure of myosin. The molecular structure and the antigenicity of myosin isoforms is different in skeletal, cardiac, and smooth muscle. We investigated whether different isoforms of myosin heavy chains are present in smooth muscle from human lungs. We observed that the distribution of three isoforms of smooth muscle myosin heavy chains is different in airways compared to pulmonary arteries, and in central airways and arteries compared to lung parenchyma. We also observed that asthmatic subjects have a similar distribution, but different immunoreactivity of myosin heavy chains in bronchial smooth muscle compared to normal subjects. These data suggest that changes in the contractile properties of smooth muscle in human lungs may be associated with changes in myosin heavy chain isoforms.

To determine whether late asthmatic reactions and the associated increase in airway responsiveness induced by toluene diisocyanate (TDI) are linked to airway inflammation, we investigated whether they are inhibited by prednisone. Ten "sensitized" subjects were studied in 2 sets of experiments. In the first set, each subject was given no treatment and was studied before and for 8 h after exposure to TDI. In the second set, 2 to 4 wk later, each subject was studied before treatment and then during treatment with prednisone (50 mg once a day for 3 days, orally), both before and after exposure to TDI. To assess late asthmatic reactions to TDI, we measured FEV1 immediately before and after exposure, then hourly for 8 h. To assess changes in airway responsiveness, we measured the provocation dose (mg) of methacholine causing a 20% decrease in FEV1 (PD20FEV1) before and 8 h after exposure to TDI. When the subjects received no prednisone treatment, TDI caused late asthmatic reactions and increased airway responsiveness. By contrast, when the subjects received prednisone, TDI caused no late asthmatic reaction or increased airway responsiveness. Prednisone did not change baseline airway caliber or airway responsiveness. These results suggest that late asthmatic reactions and the associated increase in airway responsiveness induced by TDI in "sensitized" subjects may depend on the development of a steroid-responsive acute inflammatory reaction within the airways.

We investigated the intensity and duration of the effect of a single dose of slow-release theophylline on bronchial hyperresponsiveness to ultrasonically nebulized distilled water in asthma. In six subjects with a history of mild asthma, we measured airway responsiveness to ultrasonically nebulized distilled water and serum theophylline at 4, 8, and 12 hours after treatment with placebo or slow-release theophylline (10 +/- 1 mg/kg, orally). To assess bronchial responsiveness, dose-response curves were established by plotting the baseline value of FEV1 and the largest FEV1 after each doubling dose of nebulized distilled water against the dose of nebulized water. The degree of bronchoconstriction induced by ultrasonically nebulized distilled water was significantly inhibited at 4, 8, and 12 hours after treatment with theophylline, at serum levels of 14.8 +/- 4.6, 14.4 +/- 2.8, and 12.0 +/- 2.5 micrograms/mL theophylline (mean +/- SD). Tremor occurred in three patients and was associated with nausea, epigastric pain, and tachycardia in one of them. We conclude that a single dose of slow-release theophylline has a prolonged protective effect on bronchoconstriction induced by ultrasonically nebulized distilled water, but in some subjects is associated with side effects that limit its clinical usefulness.

In asthmatic subjects, the degree of bronchial hyperresponsiveness correlates with the severity of asthma and the amount of treatment required to control asthma. Both in normal and in asthmatic subjects, the degree of airway responsiveness may increase after viral infections, exposure to oxidant pollutants and allergens or sensitizing agents; however, airway hyperresponsiveness is quite stable in the absence of exposure to inflammatory stimuli, suggesting that there are at least two components in airway hyperresponsiveness: a transient component, caused by airway inflammation, and a long-lasting one, unrelated to exposure to acute inflammatory stimuli, which is hypothesized to be due to changes in the autonomic innervation or in the smooth muscle itself.

We investigated whether late asthmatic reactions and the associated increase in airway responsiveness induced by toluene diisocyanate (TDI) in sensitized subjects are inhibited by indomethacin and/or prednisone. Four sets of experiments were conducted in five subjects sensitized to TDI. To assess late asthmatic reactions to TDI, FEV1 was measured immediately before and after exposure to TDI and then hourly for 8 h. To assess change in airway responsiveness, the provocative dose (mg) of methacholine that caused a decrease in FEV1 of 20% (PD20FEV1) before treatment, and then before and after exposure to TDI was measured. In the first set of experiments, each subject was given no treatment and was studied before and 8 h after exposure to TDI; in the other two sets, each subject was studied before treatment, then during treatment with indomethacin (50 mg q.i.d. for 3 days, orally) or prednisone (50 mg once a day, for 3 days, orally), both before and 8 h after TDI exposure. In a fourth series of experiments, each subject was again given no treatment and studied before and 8 h after TDI. When the subjects were given no treatment or indomethacin, TDI caused late asthmatic reactions and increased airway responsiveness to inhaled methacholine. In contrast, when the subjects were given prednisone, TDI caused neither late asthmatic reactions nor increased airway responsiveness. Treatment with indomethacin and prednisone did not change baseline FEV1 and airway responsiveness. These results suggest that release of prostaglandins does not contribute to late asthmatic reactions and the associated increase in airway responsiveness induced by TDI. Inflammatory mediators inhibited by prednisone but not by indomethacin may be involved.

Thirty-five subjects with occupational asthma due to toluene diisocyanate (TDI) exposure were examined. All the subjects were studied with inhalation challenges with TDI and with methacholine. TDI asthma was documented by a positive inhalation challenge to low levels of TDI. Airway responsiveness to methacholine was in the range of asthmatic patients at the time of diagnosis. After an average follow-up interval of 10 months, all the subjects were re-examined. Of the 35 subjects examined, 30 subjects (85.7%) left the workplace, and 5 remained in the same job. Twenty-seven subjects (77.1%) continued to have asthmatic attacks requiring medication for relief of symptoms. At follow-up examination, TDI asthma was documented by a positive inhalation challenge to TDI in 27 subjects. Of these 27 TDI reactors, 22 subjects were removed from occupational exposure to TDI. The TDI reactors had persistent respiratory symptoms and airway hyperresponsiveness to methacholine. At follow-up visit, 8 subjects (22.9%) lost sensitization to TDI; 5 subjects (62.5%) in this group had also normal airway responsiveness to methacholine after removal from exposure. Only 1 subject among the TDI nonreactors complained of mild respiratory symptoms. At diagnosis, there were no significant differences between subjects who recovered and those who did not with regard to age, smoking habits, atopy, duration of exposure to isocyanates, duration of symptoms, baseline FEV1 (% pred), and baseline airway responsiveness to methacholine.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-inflammatory steroids are the principal agents for the treatment of asthma. Systemic corticosteroids are recommended for the treatment of acute episodes of asthma, whereas inhaled steroids should be used in the long-term prophylaxis of asthma. Because of their side-effects, there is a need for additional research and development of steroids without systemic activity, and/or other anti-inflammatory agents for use in the long-term prophylaxis of asthma.

Six workers with occupational asthma due to toluene diisocyanate (TDI) were studied. For each worker a detailed clinical and occupational history was taken, and lung function measurement and skin intradermal tests for common allergens were carried out. Methacholine inhalation challenge was performed before TDI inhalation, and 8 h after TDI inhalation. Methacholine challenge was within normal limits when performed before TDI inhalation, but went into the asthmatic range after TDI inhalation. These cases provide evidence that asthma can be induced by toluene diisocyanate in the absence of airway hyperresponsiveness. They further demonstrate that an isolated negative methacholine inhalation test cannot be used to exclude sensitization to TDI. Screening and follow-up studies on workers exposed on TDI require serial measurements of airway responsiveness and of variable air-flow obstruction.

To determine whether 4 drugs used in the treatment of asthma inhibit the late asthmatic reaction and the associated increase in airway responsiveness induced by toluene diisocyanate (TDI), we studied 24 sensitized subjects divided into 4 groups. Beclomethasone aerosol (1 mg bid), slow-release theophylline (6.5 mg/kg bid), slow-release verapamil (120 mg bid), and cromolyn (20 mg qid via spinhaler), were administered for 7 days, respectively, to 1 of the 4 groups, according to a double-blind, crossover, placebo-controlled study design. When the subjects were treated with placebo, verapamil, or cromolyn, FEV1 markedly decreased and airway responsiveness increased after exposure to TDI. By contrast, beclomethasone prevented the late asthmatic reaction and the associated increase in airway responsiveness to methacholine induced by TDI. Slow-release theophylline partially inhibited both the immediate and the late asthmatic reactions but had no effect on airway hyperresponsiveness to methacholine. These results suggest that only high-dose inhaled steroids can completely block TDI-induced late asthmatic reactions.

In order to determine whether treatment with ketotifen inhibits asthmatic reactions induced by toluene di-isocyanate (TDI), we studied six sensitized subjects with previously demonstrated dual or late asthmatic reaction after inhalation challenge with TDI. Ketotifen (1 mg b.i.d., orally) or placebo was administered for 7 days to the examined subjects, according to a double-blind, cross-over, placebo-controlled study design. When the subjects were treated with either ketotifen or placebo, FEV1 markedly decreased after exposure to TDI. These results suggest that the anti-asthmatic agent ketotifen is not effective in TDI-induced asthma and suggest that it should not be used in the prophylaxis of asthmatic reactions induced by TDI in sensitized subjects.

Contractility of tracheal smooth muscle strips and spiral strips of fourth to fifth generation bronchi was studied in organ baths. The relationship among contractility, airway smooth muscle myosin, and smooth muscle thickness was also examined. The trachea was divided into three segments, each consisting of 12-14 rings. Smooth muscle strips from each of the three regions (top, middle, and bottom of the trachea) and from fourth to fifth generation bronchi were studied. Acetylcholine (ACh) sensitivity (-log EC50) was 8.1, 7.1, 7.9, and 6.1 for the top, middle, and bottom of the trachea and the bronchi, respectively. At P = 0.01, the EC50 ACh value of the top of the trachea differed from the EC50 value of the bronchi. Maximal tension (Tmax) generated in bronchi (3.2 g) was lower (P less than 0.01) than in the top (10.4 g), middle (7.1 g), and bottom of the trachea (5.1 g). Differences between trachea and bronchi disappeared when Tmax was corrected for smooth muscle myosin content. Thickness of smooth muscle in bronchi was less (P less than 0.01) than in the three regions of trachea. Tmax was significantly correlated with airway smooth muscle thickness (r = 0.56; P less than 0.05). These results suggest that in mongrel dogs sensitivity to ACh shows a gradient from the top of the trachea to the bronchi and that Tmax is greater in the trachea than in the bronchi and is significantly correlated with thickness of smooth muscle.

To determine whether inhaled beclomethasone, both at low and at high doses, inhibits late asthmatic reactions and the associated increase in airway responsiveness induced by toluene diisocyanate (TDI), we studied 9 sensitised subjects. Low dose beclomethasone (200 micrograms bid), high dose beclomethasone aerosol (1000 micrograms bid), and placebo were administered for 7 days before TDI inhalation challenge to each subject, according to a double-blind, crossover study design. The washout period between the treatments was at least 1 week. When the subjects were treated with placebo, forced expiratory volume in 1 sec (FEV1) markedly decreased after exposure to TDI. By contrast, high dose beclomethasone prevented the late asthmatic reaction and the low dose partially inhibited the reaction. With placebo the mean (+/- SE) value of FEV1 4 h after exposure to TDI was 2.6 +/- 0.17 L, which went to 3.3 +/- 0.12 after low dose beclomethasone, and to 3.5 +/- 0.15 L after high dose of beclomethasone (significant difference in the decrease of FEV1 in the 8 h after exposure to TDI, between treatments: F = 9.87, (P less than 0.001), After treatment with placebo or with low dose beclomethasone, airway responsiveness to methacholine increased 8 h after exposure to TDI. With placebo, the PD20 decreased from 0.66 mg (Geometric Standard Error of the Mean [GSEM], 1.38) to 0.18 mg (GSEM, 1.46); with low dose inhaled beclomethasone, the PD20 decreased from 0.93 mg (GSEM, 1.42) to 0.36 mg (GSEM, 1.63).(ABSTRACT TRUNCATED AT 250 WORDS)

The myosin heavy-chain composition of human smooth muscle has been investigated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, enzyme immunoassay, and enzyme-immunoblotting procedures. A polyclonal and a monoclonal antibody specific for smooth muscle myosin heavy chains were used in this study. The two antibodies were unreactive with sarcomeric myosin heavy chains and with platelet myosin heavy chain on enzyme immunoassay and immunoblots, and stained smooth muscle cells but not non-muscle cells in cryosections and cultures processed for indirect immunofluorescence. Two myosin heavy-chain isoforms, designated MHC-1 and MHC-2 (205 kDa and 200 kDa, respectively) were reactive with both antibodies on immunoblots of pyrophosphate extracts from different smooth muscles (arteries, veins, intestinal wall, myometrium) electrophoresed in 4% polyacrylamide gels. In the pulmonary artery, a third myosin heavy-chain isoform (MHC-3, 190 kDa) electrophoretically and antigenically distinguishable from human platelet myosin heavy chain, was specifically recognized by the monoclonal antibody. Analysis of muscle samples, directly solubilized in a sodium dodecyl sulfate solution, and degradation experiments performed on pyrophosphate extracts ruled out the possibility that MHC-3 is a proteolytic artefact. Polypeptides of identical electrophoretic mobility were also present in the other smooth muscle preparations, but were unreactive with this antibody. The presence of three myosin heavy-chain isoforms in the pulmonary artery may be related to the unique physiological properties displayed by the smooth muscle of this artery.