Lung pathogenesis. VIII. Relationships between alveolar surfactant disorders and development of lung diseases

The new data concerning the structure and dynamics of the alveolar surfactant, its phospholipid and apoprotein components and their synthesis, storage and secretion by the large granular alveolocytes, the formation and disconnection of lipoprotein complexes, their disorders and pathological relationships were analysed in order to discern the possibility of a more or less important pathogenetic role in the onset and development of lung diseases. Sometimes, surfactant disorders appeared as epiphenomena, like in pulmonary edemas; at other times, they behaved as a turn plate enhancing and centering the development of alveolar lipoproteinosis, microlithiasis alveolaris, hyaline membrane disease of newborns and the adult respiratory distress syndrome. Focusing the pathogenesis on the surfactant disorders and on their causes, a unification of mechanisms became possible with the increase in complexity of processes by the intervention of other complicating factors, mainly the self-perpetuating ones.     

Isolation, culture, and some morphohistochemical features of endothelial cells of the pulmonary microvasculature

Taking into account the quantitative and qualitative importance of endothelial cells of the pulmonary microvasculature (40 per cent of all lung mesenchymal cells, 26 per cent of all lung cells) the authors attempted their isolation, culture in vitro and specification of some morphohistochemical characters, using the method of Habliston et al. (1979). There were used guinea pigs and rabbits and a 0.5 and 1 per cent trypsin solution in a retrograde perfusion for the detachment of endothelial cells from their rbasement membranes. The obtained cells were maintained in culture for5 7--9 days and morphologically characterized; their caveolar enzymes were evidenced (Mg-dependent ATP-ase, acid and alkaline phosphatases, a.o.).     

Arguments for a histogenetic classification of lung carcinomas

Taking into consideration the common origin of lung carcinomas from the basal-intermediate cells of covering epithelia of bronchi and bronchioles (which have preserved their ability to divide and differentiate under different stimuli), and the development of tumors in at least two phases, the main histogenetic characteristics of lung carcinomas are discussed. There are pointed out the various and multiple promoting factors acting at the level of proliferating cell foci resulted from the initiating action of chemical carcinogens and the varied deepness of the cellular changes induced. Under these conditions, the malignantly transformed cells may remain poorly differentiated, like during the histogenesis of macrocellular carcinomas (which might be influenced in the course of proliferation, within some limits, by active factors), they may preserve the stereotype of cylindrocubic development, like during the formation of cylindrocubic carcinomas (bronchiolo-alveolar cell carcinomas included), or may suffer metaplastic changes and form subsequently epidermoid carcinomas; the inclusion of Kultschitzky-APUD cells within proliferating foci may lead to bronchial carcinoids or to microcellular carcinomas. The particular forms of lung carcinomas (giant celled, adenocystic, mucoepidermoid) histogenetically reflect the mixed or concomitant stereotypical evolutions of basal cells while preserving some secretory possibilities.     

The cylindrocubic carcinomas of the lung (the so-called adenocarcinomas). A histopathological analysis of 725 cases

A histopathological and histochemical analysis of 725 cases of cylindrocubic carcinomas of the lung was performed: 570 cases were surgically removed specimens, 98 bronchial and 46 extrathoracal biopsies from unoperable cases, and 11 autopsies. Histopathology of operated cases revealed the co-existence and intrication in different proportions of immature cell areas with dense proliferations containing many giant, monstrous cells, with others trabecular, acinar, cribriform-areolar, pseudoglandular, tubular, papillar and glandular-secretory areas; most of these cellular dispositions were related to the lung stromal development (scars, fibrotic areas); 117 out of the 570 cases were independent, multicentric, true bronchiolo-alveolar carcinomas, and 48 cases were true glandular-secretory carcinomas of the large bronchi. 143 out of the 570 cases developed upon scars and fibrotic areas; in 42 out of these 143 the pericicatricial invasion was bronchiolo-alveolar-like. The study of small tumors and of bronchial biopsies revealed mostly the peripheral origin of these cylindrocubic carcinomas from the bronchial covering epithelia of small, nonglandular bronchi. The term of adenocarcinoma does not correspond to the predominant histological picture of these lung tumors, and the so-called subtypes of the WHO typing are currently represented in the same tumors concomitantly and in various proportions. The histodiagnosis of these lung carcinomas is facilitated by the presence of well differentiated, glandular-secretory areas and has to be based upon the predominant aspects of the tumoral growth.