A. W. J. Lykke

Cell separation: a review

Summary “This review summarizes currently available techniques for cell separation”. Techniques that exploit differences in physical properties of cells are widely used but have a number of limitations. Those that are based on differences in surface properties may more readily permit reproducible separation of a functionally homogeneous population of cells. Unfortunately very few techniques achieve separation of cells on the basis of differences in their functional characteristics.

Development and Characterization of Type 2 Pneumocyte-Related Cell Lines from Normal Adult Mouse Lung

&NA; Cell lines which exhibit epithelial morphology with surface microvilli and inclusion bodies characteristic of type 2 pneumocytes have been derived from normal adult mouse lung by a simple procedure involving enzymatic dispersal and mechanical elimination of other cell types. One of these cell lines designated NAL 1A, examined in detail, shows features consistent with its being related to type 2 pneumocytes of mouse lung. These features include desmosomes, dense lamellar bodies as well as phospholipid profiles related to immature surface active material, the inhibition of cell growth rate by dexamethasone, and the close similarity of the cytoskeletal protein patterns of this cell line to those of a metastatic type 2 pneumocyte‐related cell line of mouse lung. The cell line from normal lung demonstrated near diploid chromosome number at low passage number with some evidence of karyotype instability at high passage number.

Reduced yield of pulmonary surfactant: Patterns of response following administration of chemicals to rats by inhalation

Repeated exposure of rats to trichloroethylene, carbon tetrachloride, gasoline vapour or to cigarette smoke is followed by significant reduction in the recovery of pulmonary surfactant, inhibition being evident as early as 5 days after commencement of treatment. The degree of reduction in surfactant recovery was dose-dependent and the kinetics of this reaction indicated the relative toxicities of the treatments. The results are discussed with reference to the use of surfactant recovery as an indicator of non-specific injury to respiratory tissue.

Messages and handshakes: cellular interactions in pulmonary fibrosis.

&NA; A better understanding of early cellular events following pulmonary injury may permit the identification of those patterns of response which are destined to progress to fibrosis. Interactions between inflammatory, fibroblastic and epithelial cells appear to play crucial roles in fibrogenesis. Intercellular communication may be via “messages” delivered by soluble mediators or “handshakes” at sites of cell‐to‐cell contact. In this review, we question the validity of some prevailing concepts about the importance of growth factor secretion by alveolar macrophages; examine the possible role of activated T‐lymphocytes in regulating macrophage production of mediators; and hypothesise that whereas fibroblast proliferation may primarily be stimulated by macrophage‐derived cytokines, accumulation of collagen may be regulated by growth factors expressed by injured alveolar epithelial cells.

Multiple Biogenic Amine-Secreting ‘Carcinoid’ Tumour of the Stomach: A Case Report

Summary An unusual case of a gastric carcinoid tumour producing multiple biogenic amines is described in a patient with pernicious anaemia. Electron microscopy demonstrated two distinct types of secretory granules.

Establishment of epithelial cell strains from normal adult mouse lung resembling a urethane-induced lung adenoma cell strain and a metastasizing mouse lung carcinoma cell line

Epithelial cell strains, designated NAL, have been established from normal lungs of adult female Balb/c mice. The ultrastructural characteristics, effect of dexamethasone on cellular morphology and proliferation rate, and the cytoskeletal protein pattern of NAL suggests that these cell strains may be related to a urethane-induced mouse lung adenoma cell strain NUL and to a metastasizing mouse lung tumour cell line CMT. NAL exhibited no anchorage-independent growth under normal conditions, however extensive passaging in the presence of 5 X 10(-6)M dexamethasone resulted in a colony forming efficiency in soft agar of 8.4% at passage number 30.

Correlation of biochemical and morphological changes induced by chemical injury to the lung.

Comparison has been made of injury to the rat pulmonary alveolar parenchyma evoked by intravenous injection of N-nitrosomethylurethane, intratracheal instillation of 3-methylcholanthrene or repeated inhalation for up to 15 days of carbon tetrachloride, trichloroethylene or gasoline vapour. Biochemical analyses, including assessment of rates of RNA and DNA synthesis and secretion of pulmonary surfactant, were correlated with morphological changes determined by electron microscopy. Single doses of N-nitrosomethylurethane or 3-methylcholanthrene inhibited incorporation of [14C] orotate into lung RNA 1--3 days after treatment. Daily exposure for 30 min to carbon tetrachloride or trichloroethylene vapour caused less marked reduction in orotate incorporation. Ultrastructural examination revealed that 3-methylcholanthrene toxicity was characterised by cytoplasmic change including disruption of surfactant lamellaie of Type 2 pneumocytes and variable degenerative changes Type 1 pneumocytes. Eight to ten days after treatment, the morphological evidence of hypertrophy/hyperplasia and transformation of Type 2 pneumocytes correlated well with biochemical evidence of stimulated incorporation of [3H]thymidine. Inhalation of carbon tetrachloride or trichloroethylene vapour produced milder responses including occasional degenerative changes in Type 1 pneumocytes, reduced numbers of surfactant lamellae in Type 2 pneumocytes and no change in [3H]thymidine incorporation. In contrast to the gradation of injury produced by the various chemicals, all procedures caused a marked and reproducible reduction in secretion of pulmonary surfactant as determined by endobronchial lavage. Following solvent inhalation, reduced recovery of surfactant was detected within 5 days of repeated exposure and thereafter no further change in this depressed level resulted from continued exposure for a further 10 days. The data are discussed in terms of a generalised pattern of response by pulmonary alveolar tissue to chemical injury and the apparent sensitivity of surfactant secretion as an indicator of damage to the lung.

Pulmonary responses to atmospheric pollutants. I: an ultrastructural study of fibrosing alveolitis evoked by petrol vapour

Rats exposed to an atmosphere contaminated with petrol vapour at a concentration of 100 parts per million for up to 12 weeks exhibit a high incidence of electron microscopic changes in the lung parenchyma characterized by interstitial fibrosis with associated alveolar collapse. Initial changes appearing after 6 weeks include degeneration of endothelium and interstitial fibroblasts followed by hypertrophy of Type 2 pneumocytes. Subsequent degeneration of surfactant organelles of the hypertrophied Type 2 pneumocytes correlates with the appearance of focal alveolar collapse and associated interstitial fibrosis. Because of the rapidity with which lesions are induced in the rat lung, this experimental technique provides an economical and reproducible model for an integrated study of the sequential morphological and biochemical events preceding pulmonary fibrosis which might well lead to a better understanding of the enigmatic human syndrome of fibrosing alveolitis.

Pulmonary responses to bleomycin-induced injury: an immunomorphologic and electron microscopic study

Intratracheal injection of a small dose of bleomycin in rats induced early alveolar epithelial cell injury and a pneumonitis which subsequently evolved to pulmonary fibrosis. Hydropic degeneration of type I pneumocytes was apparent at 3 days after treatment. Marked interstitial and intra-alveolar pneumonitis developed at 7 days after treatment and was accompanied by hypertrophy and hyperplasia of type II pneumocytes. The inflammatory cell population consisted predominantly of cells with the morphology of large lymphocytes together with a number of eosinophils. Examination by immunoperoxidase and histochemical staining of frozen sections revealed that the lymphoid cells stained positively with the monoclonal antibodies W3/13 and W3/25 but not with other markers. Thus these cells appeared to be helper T lymphocytes. The later development of interstitial fibrosis was accompanied by alveolar microcollapse which contributed to the thickening of alveolar septa observed by light microscopy. The possible role of immunologic and other mechanisms in the pathogenesis of bleomycin-induced pulmonary fibrosis is discussed.

Increased vascular permeability evoked by cold injury

Summary The inflammatory response induced by mild freezing of the skin of the rat is monophasic and short‐lived. Increments in the intensity and/or duration of the stimulus increase the magnitude of the initial exudation, as well as evoking a biphasic response. Nevertheless, the initial response always dominates the permeability effects. Relatively severe freezing provokes marked and prolonged exudation. The permeability response involves both venules and capillaries in all its phases, although the initial leakage is predominantly from venules. Progressive increase in the severity of the stimulus enhances capillary labelling and, as judged histologically, causes considerable vascular damage. Histological damage is reversible with freezing severe enough to elicit a delayed permeability response, but stronger stimulation results in compaction stasis, endothelial damage and necrosis of skin.