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Lung macrophages may play a relevant role in oxidative processes producing both superoxide anion (O(2)(-)) and NO. In this view, an antioxidant therapy can be useful in the treatment of systemic sclerosis (SSc) patients. N-Acetylcysteine (NAC) is able to expand natural antioxidant defenses by increasing intracellular gluthatione concentration and it has been proposed as an antioxidant therapy in respiratory distress syndromes. The aim of our study was to determine whether lung macrophages obtained from SSc patient bronchoalveolar lavage (BAL) express the inducible form of nitric oxide synthase (iNOS) and whether NAC can reduce the peroxynitrite (ONOO(-)) and O(2)(-) production of these cells. Alveolar macrophages were isolated from BAL of 32 patients and used for the immunocytochemical determination of iNOS, and the production of ONOO(-) and O(2)(-) was measured by fluorimetric or spectrophotometric methods, respectively. Lung macrophages obtained from SSc patients expressed a higher level of iNOS compared to healthy subject cells. NAC preincubation (5 x 10(-5)M, 24h) significantly reduced (-21%) the ONOO(-) production in formyl Met-Leu-Phe (fMLP)-activated cells and slightly reduced it under resting conditions, whereas NAC preincubation was unable to modify the release of O(2)(-) both in basal condition and in fMLP-stimulated cells. We conclude that since SSc lung macrophages express high levels of iNOS and produce a significant quantity of ONOO(-), NAC administration reduces ONOO(-) production and can be an useful treatment to alleviate SSc symptoms.

The purpose of this contribution is to place a higher value on the existence of a turn-over of bronchial and pulmonary elastic fibers: the former would derive from the smooth muscle cells of the bronchial wall, the latter from the interstitial myofibroblasts of the alveolar septa. The reduction of the number of the elastic fibers in the bronchial wall during chronic atrophic bronchitis depend on the atrophy of the bronchial smooth muscle cells; in the alveolar septa the hyperplasia of the elastic fibers during pulmonary fibroses depend on the myofibroblastic proliferation, while the reduction of the elastic fibers number during pulmonary enphysema depend on the reduction in the number of myofibroblasts.

Considering the role proposed for myofibroblasts in inflammatory and hyperelastotic lung diseases, the possibility arises that these cells are involved in bronchial pathology, including asthma. To address this issue, we have analyzed by light microscopy, histochemistry and immunohistochemistry the structure of extra- and intra-pulmonary bronchi of patient died of asthma. We have demonstrated hyperplasia of connective tissue cells and fibers in the mucosa, all around the lumen of extra- and intra-pulmonary bronchi. The cells were thin and elongated, labeled by anti-actin and anti-vimentin antibodies and interspersed with many elastic and collagen fibers, therefore they were interpreted as myofibroblasts. These findings may explain the rigidity of the bronchial wall in patients with asthma, which causes the progressively more limited resolution of airway obstruction upon pharmacological treatment and the gross anatomical finding of bronchial stiffness at inspection of the lungs. The possibility should also be considered that myofibroblasts and elastic--not collagen--fibers have contributed to bronchial hyperreactivity at an early stage of the disease.

On the possible ontogeny of the cells of a "granular cell tumor" of the human trachea. In a young patient affected with pulmonary tuberculosis during bronchoscopy a "granular cell tumor" of the membranous part of trachea was occasionally evidentied. After pathologic examination, the specimen is analyzed in order to assess the kind of cells that are present in the lesion: the ultrastructural and immunohistochemical study shows Schwann cells which particularly well developed lysosomal complement.

A new framework for pulmonary fibroses may be obtained by distinguishing the "true" forms (solely collagen hyperplasia) from the "false" forms or mesenchymal fibril lung diseases (collagen, reticular and elastic hyperplasia with neo-angiogenesis): the "true fibroses" are then divisible into those not causing architectural subversion of the lung and those which bring it about. Pulmonary architectural subversion is common to true granulomatous fibroses and mesenchymal fibril lung diseases: it is, in our opinion, the product of a combination of factors, including the hyperactivity of a fibroblast sub-population normally in the minority, stimulated by T lymphocytes which are activated by an autoimmune response to type I collagen produced in excess.