Biomedical subjects

P Maestrelli

Publications and source records attributed to P Maestrelli.

At least 19 recordsLinked to original sources

PubMed1992

Activated T-lymphocytes and eosinophils in the bronchial mucosa in isocyanate-induced asthma.

We have studied the phenotype and activation status of leukocytes in the bronchial mucosa in patients with isocyanate-induced asthma. Fiberoptic bronchial biopsy specimens were obtained from nine subjects with occupational (five toluene- and four methylene diisocyanate-sensitive) asthma, 10 subjects with extrinsic asthma, and 12 nonatopic healthy control subjects. Bronchial biopsy specimens were examined by immunohistology with a panel of monoclonal antibodies and the alkaline phosphatase-antialkaline phosphatase method. There was a significant increase in the number of CD25+ cells (interleukin-2 receptor-bearing cells, presumed "activated" T-lymphocytes; p less than 0.01) in isocyanate-induced asthma compared with that of control subjects. There were also significant increases in major basic protein (BMK-13)-positive (p less than 0.02) and EG2-positive (p less than 0.01) cells that represent total and "activated" eosinophil cationic protein-secreting eosinophils, respectively. In agreement with our previous findings, CD25+ (p less than 0.01), BMK-13 (p less than 0.03), and EG2+ (p less than 0.01) cells were also elevated in extrinsic asthma. No significant differences were observed in the numbers of T-lymphocyte phenotypic markers (CD3, CD4, and CD8) between subjects with asthma (isocyanate-induced and extrinsic) and control subjects. Similarly, no significant differences in immunostaining for neutrophil elastase (neutrophils) or CD68 (macrophages) were observed. The results suggest that isocyanate-induced occupational asthma and atopic (extrinsic) asthma have a similar pattern of inflammatory cell infiltrate. The results support the view that T-lymphocyte activation and eosinophil recruitment may be important in asthma of diverse etiology.

Adult↗

PubMed1992

Airway mucosal inflammation in occupational asthma induced by toluene diisocyanate.

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.

Adolescent↗

PubMed1992

Effect of cessation of exposure to toluene diisocyanate (TDI) on bronchial mucosa of subjects with TDI-induced asthma.

The effect of cessation of exposure to toluene diisocyanate (TDI) was studied in six patients with TDI-induced asthma, proved by a positive inhalation challenge with TDI. Bronchial challenges with TDI and methacholine were performed, and lobar bronchial biopsies were taken at diagnosis and 6 months later, after cessation of exposure. Biopsies from four nonasthmatic control subjects were also examined. At diagnosis, asthmatic subjects had thickened reticular basement membrane (p less than 0.05) and increased numbers of mononuclear cells (p less than 0.05) and eosinophils (p less than 0.05) in the lamina propria when compared with control subjects. Electron microscopy showed degranulation of eosinophils and mast cells in asthmatics. Six months after cessation of exposure, the thickness of reticular basement membrane was significantly reduced compared with that at diagnosis (p less than 0.05), and it decreased to values similar to those of control biopsies. Inflammatory cell numbers in bronchial mucosa of asthmatic subjects did not change significantly 6 months after removal from exposure, and degranulation of eosinophils and mast cells was still present. At the end of the study, airway hyperresponsiveness to methacholine and/or sensitivity to TDI persisted in most of the asthmatic patients despite the cessation of exposure and the disappearance of asthmatic symptoms. In conclusion, in patients with occupational asthma induced by TDI, the avoidance of exposure to the sensitizing agent for 6 months is able to reverse the reticular basement membrane thickening in the bronchial mucosa, but the inflammatory cell infiltrate, the specific sensitivity to TDI, and the nonspecific airway hyperreactivity may persist.

Adult↗

PubMed1991

Increase in numbers of CD8 positive lymphocytes and eosinophils in peripheral blood of subjects with late asthmatic reactions induced by toluene diisocyanate.

Occupational asthma induced by toluene diisocyanate (TDI) shares several features with allergic asthma, but the mechanism of action of TDI is poorly understood. Ten sensitised subjects, previously shown to develop a dual or late asthmatic reaction after inhaling TDI were examined. In each subject, forced expiratory volume in one second (FEV1) was measured and venous blood was taken before, and 30 minutes and eight, 24, 48, and 72 hours after exposure to TDI (0.005-0.015 ppm for 10-30 minutes). Filtered air was used as a control. Differential leucocyte counts were determined and phenotypic analysis was performed by immunofluorescence on mononuclear cells using monoclonal antibodies (anti-CD3, anti-CD4, anti-CD8, and anti-HLA-DR). Five subjects developed a dual asthmatic reaction and five had a late reaction. Percentage of CD8 positive lymphocytes increased significantly eight hours after exposure to TDI (from 27 +/- 3 (SEM) % to 42.1 +/- 5%) in the subjects with an isolated late reaction. A delayed significant further increase in suppressor/cytotoxic T lymphocytes was seen in seven of the 10 subjects 48 hours after active exposure (from 27 +/- 2% to 42 +/- 4.8%), irrespective of the type of asthmatic reaction developed after exposure to TDI. Eosinophil percentage increased from 2.5% +/- 1.0 to 6.4% +/- 1.2 24 hours after exposure to TDI and the increase was sustained for up to 48 hours (4.7 +/- 1.1%). No significant variations of FEV1 or cell percentages were seen in the controls. In conclusion, the events triggered by exposure to TDI in sensitised subjects included changes in lung function and systemic effects which lasted longer than bonchoconstriction and concerned suppressor/cytotoxic lymphocytes and eosinophils. These results suggest that TDI induced late asthmatic reactions may be associated with an immunological response to TDI or to its products.

Adult↗

PubMed1991

Airway inflammation during late asthmatic reactions induced by toluene diisocyanate.

To determine the importance of airway inflammation for the development of late asthmatic reactions, we examined sensitized subjects during late asthmatic reactions induced by exposure to toluene diisocyanate (TDI) in the laboratory. Late asthmatic reactions are associated with a transient increase of bronchial responsiveness and, at the same time, with an increase of neutrophils followed by eosinophils, and of LTB4 and albumin in bronchoalveolar lavage fluid. Late asthmatic reactions, increased bronchial responsiveness, and increase of neutrophils, eosinophils, LTB4, and albumin concentration in bronchoalveolar lavage induced by exposure to TDI are all prevented by pretreatment with prednisone but not with the nonsteroidal anti-inflammatory agent indomethacin. Aerosolized steroids (beclomethasone and dexamethasone isonicotinate) completely inhibit late asthmatic reactions induced by TDI, whereas theophylline has a partial, and verapamil, ketotifen, and cromolyn have no protective effect. These results suggest that late asthmatic reactions induced by TDI may be caused by airway inflammation, and that anti-inflammatory steroids should be recommended in the prophylaxis of TDI asthma.

Asthma↗

PubMed1990

Venous blood platelets decrease during allergen-induced asthmatic reactions.

To determine whether circulating platelets alter during asthmatic reactions induced by allergens, we studied nine subjects previously shown to develop an early or dual asthmatic reaction after inhalation challenge with extracts of house dust mite or grass pollen. In each subject, FEV1, circulating platelets and leucocytes were measured before, 15, 30 and 60 min, and 2, 4, 6 and 8 hr after inhalation of allergen and diluent control administered in a single-blind, randomized fashion. The same procedure was repeated in six of the nine subjects after bronchoconstriction induced by methacholine. Each subject developed an early asthmatic reaction after allergen inhalation challenge, which was followed by a late asthmatic reaction in six subjects and by an equivocal late asthmatic reaction in two of them (fall in FEV1 of 15 and 17% respectively). Compared with the control day, circulating platelets significantly decreased during the allergen-induced early asthmatic reaction (P less than 0.025, at 30 min). Platelet counts returned to baseline values within 4 hr and remained steady thereafter both in subjects who did and did not develop a late asthmatic reaction. No changes in platelet counts occurred after bronchoconstriction induced by methacholine. Diurnal increase of leucocyte numbers occurred after challenge with both allergen and diluent control. These results suggest that platelets may be involved in the pathogenesis of allergen-induced asthmatic reactions.

Adolescent↗

PubMed1989

Leukotriene release enhancing factor. Purification, specific allergen induction, and further biologic properties.

Human PBMC cultured with PHA produced a factor which enhanced neutrophil LTB4 production. After progressive purification by gel filtration and chromatofocusing, leukotriene release enhancing factor (LREF) gave a single band on SDS-PAGE corresponding to a Mr of 60 kDa and a isoelectric point of 5.0 to 5.2. Human T lymphocytes were identified as a source of LREF because a long term human CD4+ T cell line, specific for house dust mite (Dermatophagoides farinae) generated leukotriene release enhancing activity (LREA) when stimulated with the inducing Ag together with irradiated accessory cells. Cultures of accessory cell and Ag alone did not induce neutrophil activation. Similarly, control cultures using an irrelevant allergen (grass pollen) failed to produce this activity. Stimulation of PBMC with anti-CD3 mAb also generated LREA. LREA had other neutrophil-associated biologic activities. These included the enhancement of neutrophil adherence to nylon wool, increased cytotoxicity of opsonised schistosomula of Schistosoma mansoni and upregulation of C receptors (CR1 and CR3). LREA had minimal neutrophil chemotactic activity. Therefore, LREF has potential as a mediator of inflammation and provides a link between lipid mediators, neutrophils, and cell-mediated immunity in the context of allergic diseases.

Adjuvants, Immunologic↗

PubMed1989

Ambroxol inhibits airway hyperresponsiveness induced by ozone in dogs.

To follow up previous observations that airway hyperresponsiveness induced by ozone is linked to airway inflammation and particularly to the release of arachidonic acid metabolites, we investigated the effect of ambroxol (a mucoactive and surfactant-stimulating drug that has recently been discovered to inhibit the release of arachidonic acid from cell membrane phospholipids) on airway hyperresponsiveness and bronchoalveolar neutrophilia induced by ozone in dogs. One group of 5 dogs was studied before treatment with nebulized saline and then after exposure to ozone (3 ppm, 1 h); another group of 6 dogs was studied before treatment with ambroxol (100 breaths of a 1% solution) and after exposure to ozone. On each occasion, we measured airway responsiveness to acetylcholine and counted the number of cells in bronchoalveolar lavage fluid. When the dogs were given the saline placebo, ozone induced a marked increase in airway responsiveness to acetylcholine and a marked influx of neutrophils in the airways. When the dogs were given ambroxol, ozone induced the same increase in the number of neutrophils in bronchoalveolar lavage, but did not increase the degree of airway responsiveness to acetylcholine. We conclude that ambroxol inhibits ozone-induced airway hyperresponsiveness in dogs, probably by inhibiting the formation and release of oxygenation products of arachidonic acid from neutrophils.

Acetylcholine↗

PubMed1989

T lymphocytes in allergen-induced late-phase reactions and asthma.

We have studied a number of aspects of the interrelationship between T lymphocytes and allergic inflammation. Using monoclonal antibodies and immunocytochemistry we have observed significant infiltration by CD3+/CD4+ T lymphocytes together with evidence of T cell activation in the allergen-induced late-phase skin reaction in human atopic subjects. These changes were accompanied by eosinophil infiltration and activation. Activated T cells were also detected in the blood of patients with acute severe asthma. The role of T lymphocytes in granulocyte chemotaxis and activation was also explored, using recombinant human lymphokines, and we have identified and characterized two lymphokines which have specific effects upon neutrophils.

Acute Disease↗

PubMed1988

Pathogenesis of bronchial hyperresponsiveness.

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.

Animals↗

PubMed1988

A T-lymphocyte-derived factor that enhances IgG-dependent release of leukotriene B4 (LTB4) from human neutrophils.

We describe a human blood mononuclear cell (MNC)-derived leukotriene release enhancing factor (LREF) which significantly increased IgG-dependent leukotriene B4 (LTB4) generation by neutrophils. MNCs incubated with phytohaemagglutinin (PHA) or anti-CD3 monoclonal antibody and PHA-stimulated ER+ lymphocytes produced a 150-350% increase in LTB4 generation from IgG-stimulated neutrophils. With PHA, maximal activity was observed 48 hr after culture in serum-free medium. LREF was relatively stable when exposed to low pH (pH 2) or heat (56 degrees, 60 min). Following progressive purification by gel filtration (FPLC, Superose 12) and chromatofocusing (FPLC, Mono P) LREF was associated with proteins of molecular weight of 35-40 kD and a pI of 5.1-5.5. Partially purified LREF did not contain detectable amounts of interleukin 2 (IL-2) or interferon-gamma (IFN-gamma). Although high concentrations of recombinant granulocyte-macrophage colony stimulating factor (rGM-CSF) (greater than 2 ng/ml) and recombinant tumour necrosis factor (rTNF) (greater than 100 U/ml) gave a slight (60%) enhancement of LTB4 generation, this was considerably less than that of partially purified LREF (350%). Our results suggest that human lymphocyte-derived LREF may play a role in the amplification of inflammatory reactions involving sensitized lymphocytes, neutrophils and lipid mediators.

Humans↗

PubMed1988

Antigen-induced neutrophil chemotactic factor from cloned human T lymphocytes.

Here we report the presence of a low molecular weight (10,000 neutrophil chemotactic factor (NCF) in the supernatants of activated human T lymphocytes. Appreciable amounts of the 10,000 MW NCF were generated by peripheral blood mononuclear cells (PBMC) stimulated with anti-CD3 antibody, and comparable NCF was secreted by both long-term human T-helper (CD4+) cell lines reactive with house dust mite (Dermatophagoides farinae) and influenza A virus-immune T-cell clones. When the cloned T cells were stimulated with specific antigen in the presence of irradiated accessory cells (AC) or insolubilized anti-CD3 antibody the 10,000 MW NCF was readily identifiable in 24-hr culture supernatants. Cultures of AC and antigen alone produced negligible neutrophil chemotactic activity, as did control cultures using an irrelevant allergen (mixed grass pollen). These findings indicate that the 10,000 MW NCF may be T-lymphocyte derived and that formation and release are dependent upon stimulation via the antigen receptor.

Antigens↗

PubMed1988

Occupational asthma due to isocyanates.

162 subjects who had been exposed to isocyanates, who had developed symptoms during the exposure period, or in the evening or night and, therefore, had a history compatible with isocyanate-induced asthma, were studied with inhalation challenge testing to isocyanates (toluene diisocyanate and methylene diphenyl diisocyanate) and methacholine, because they were suspected of having occupational asthma. None of these subjects had symptomatic asthma before employment. The diagnosis of occupational asthma was delayed (duration of symptoms before diagnosis: 3.9 +/- 0.4 yrs). Isocyanate-asthma documented by a positive inhalation challenge to isocyanates was present in 57.4% of the subjects. A higher degree of airway responsiveness to methacholine was present in subjects with a positive isocyanate inhalation challenge compared to subjects with a negative challenge (Gmean and GESM: 0.407 (1.14) vs 0.942 (1.14) mg). The majority of the subjects complained of shortness of breath and cough. The low proportion of atopic subjects (21.5%) and of smokers (7.5%), and the high proportion of subjects with the late component in the asthmatic reaction (71%) appear to be common features in this disease.

Adult↗

PubMed1988

The identification and partial characterization of a human mononuclear cell-derived neutrophil chemotactic factor apparently distinct from IL-1, IL-2, GM-CSF, TNF and IFN-gamma.

We have identified a neutrophil chemotactic factor (NCF) in supernatants from human blood mononuclear cells (MNC) cultured in the presence of phytohaemagglutinin (PHA). Maximal activity was observed 48 hr after culture. Following gel filtration, NCF eluted as a single major peak, together with proteins, having a molecular size of approximately 10,000 MW. The material gave a single band on SDS-PAGE but was heterogeneous following chromatofocusing (pIs approximately 6.8-7.0, 5.5-6.0 and 5.0). The biological activity of the partially purified material was abolished by trypsin and chymotrypsin treatment. NCF was heat stable (70 degrees, 60 min) and promoted both directional migration (chemotaxis) of neutrophils and, to a lesser extent, stimulated random locomotion (chemokinesis). The factor was not associated with detectable amounts of IL-1, IL-2 or interferon-gamma (IFN-gamma). MNC-derived NCF had a molecular size lower than recombinant granulocyte-monocyte colony-stimulating factor (rGM-CSF) and recombinant tumour necrosis factor (rTNF), and was considerably more active in chemotaxis. Optimal chemotactic concentrations of partially purified MNC-derived NCF were of comparable potency to FMLP and LTB4 and had about 60% of the activity of optimal concentrations of C5a, C5a-des-Arg and platelet-activating factor (PAF). These experiments indicate that the human MNC-derived NCF is a potent chemo-attractant distinct from other cytokines previously reported to promote neutrophil locomotion.

Cell Movement↗

PubMed1987

Occupational asthma due to ebony wood (Diospyros crassiflora) dust.

A 47-year-old man developed a specific late asthmatic reaction after occupational-type exposure to ebony wood dust. Intradermal skin test to an aqueous extract of ebony wood did not give any immediate or late response. The challenge with ebony wood dust was therefore the only method of confirming the cause of asthma. The mechanism underlying this asthmatic reaction remains unknown.

Asthma↗

PubMed1985

Time course of the increase in airway responsiveness associated with late asthmatic reactions to toluene diisocyanate in sensitized subjects.

To understand better the mechanism of the increase in airway responsiveness associated with late asthmatic reactions, we determined the time course of toluene diisocyanate (TDI) effect on airway responsiveness in six sensitized subjects who exhibited a late asthmatic response after TDI exposure (0.018 +/- 0.005 ppm, 30 min) in the laboratory. Airway responsiveness was assessed before TDI exposure and then at 8 hr, 1 day, 1 wk, and 1 mo after TDI exposure. To assess responsiveness we determined the provocative dose of methacholine causing a decrease in FEV1 of 20% (PD20FEV1). The methacholine PD20 decreased from 0.50 mg geometric standard error of the mean (GSEM = 1.54) to 0.06 mg (GSEM = 1.55) (p less than 0.001) at 8 hr after exposure to TDI, was still decreased to 0.15 mg (GSEM = 1.93) (p less than 0.05) at 1 day, returned to 0.26 mg (GSEM = 1.91) (p greater than 0.05) at 1 wk, and returned to 0.43 mg (GSEM = 1.71) at 1 mo, indicating that full recovery occurred within 1 to 4 wk. These results demonstrate that TDI-induced late asthmatic response is associated with a reversible increase in airway responsiveness to methacholine and suggest that the TDI effect is linked to an acute inflammatory response in the airways.

Adolescent↗

PubMed1985

Prednisone inhibits late asthmatic reactions and the associated increase in airway responsiveness induced by toluene-diisocyanate in sensitized subjects.

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.

Adult↗

PubMed1977

[Prevalence of penumoconiosis in a steel-plant (author's transl)].

Chest X-rays of 483 steel workers employed in the same factory were examined by the authors and classified according to the ILO U/C 1971 classification for pneumoconiosis. The prevalence of pneumoconiosis was found to be 8.4%. The majority of the positive cases were detected among the furnace workers and then among presse and rolling-mill workers. Only one positive case was found among the workers of the other foremen. It is stated that the furnace is the main source of pollution and that the lack of protective systems spreads the risk also to the surrounding working sites. No significant differences were found as for the opacity features.

Adult↗