Laminins (Ln) appear to play an important role in the morphogenesis of airways. We studied the expression of different laminin chains and their integrin receptors in fetal and adult lung by immunohistochemistry. Special attention was focused on the changes in the expression of these proteins during the development from the pseudoglandular (PG) and canalicular stages to adult lung, and on the possible implications of the changes for the normal lung development. The most significant changes in the expression pattern were found during the development from the PG stage to the canalicular stage. Basement membranes (BM) of both the epithelial buds and the becoming bronchi showed reactivity for Ln-alpha 1, -alpha 3, and -beta 3 chains at all stages. The alpha 2 chain was expressed only in the epithelial buds at the PG stage, and could not be found in any epithelial structures at the canalicular stage. Similarly, at the PG stage the Ln-beta 2 chain was expressed in BMs of both epithelial buds and bronchi but disappeared from the bronchial BM before the canalicular stage. Ln-beta 1 chain appeared in the bronchial BM first in the mature lung, which suggests the presence of uncharacterized Ln-beta chains earlier in development. There were considerable changes in the expression of integrins (Int) concomitantly with alterations in the composition of the BMs. At the PG stage the epithelial buds showed reactivity for Int-alpha 2 -alpha 3, and -alpha 6 subunits, but at the canalicular stage the Int-alpha 2 and -alpha 6 subunits disappeared, and only Int-alpha 3 integrin subunit was found in evolving alveolar walls; Int-alpha 6 was found in capillaries. A similar distribution of Int subunits was also found in adult alveoli. The bronchi expressed Int-alpha 2, -alpha 3, and -alpha 6 subunits at all developmental stages, but the Int-beta 4 subunit emerged first at the canalicular stage. Our results suggest that there are major changes in the expression of Ln and their Int receptors during morphogenesis of the lung, which may be important for normal development.

In this investigation, tenascin (Tn) expression was studied in 51 cases of different types of fibrotic lung disorders originating for years 1981 to 1995. Our aim was to test if accumulation of Tn at the site of lung injury in usual interstitial pneumonia (UIP) could correlate with the prognosis. Lung biopsies taken from 28 patients with UIP, six with desquamative interstitial pneumonia (DIP), six with sarcoidosis, five with extrinsic allergic bronchioloalveolitis, five with bronchiolitis obliterans organizing pneumonia (BOOP), and one with nonspecific interstitial pneumonia were studied for the expression of Tn by using an immunohistochemical technique. In addition to Tn immunohistochemistry, selected cases were also studied by immunoelectron microscopy and Western blotting. For prognostic studies in UIP the clinical follow-up information was obtained from the patient records. The expression of Tn was increased in each type of fibrosis, especially in UIP. In immunoelectron microscopy the most prominent labeling in UIP was found in association with collagen fibers and within the type 2 pneumocytes. Every studied case of UIP showed reactivity for a polypeptide of M(r) approximately equal to 200,000 by Western blotting. In patients with UIP, increased Tn expression, especially under metaplastic bronchiolar-type epithelium, was associated with a shortened survival time. Immunoelectron microscopic findings support the idea that Tn in UIP is synthesized by the regenerating epithelial rather than interstitial cells in response to pulmonary interstitial inflammation.

BF-200 ALA showed a trend towards improved efficacy results compared with MAL. Thicker lesions in both groups responded when treated repeatedly. Importantly, a thin 0·25-mm layer of the photosensitizer precursors was sufficient, which may lead to lower expense.

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Anchoring complex component laminin-5 and its subunits laminin (Ln)-alpha3 and Ln-beta3 chains, Type VII collagen, and integrin chains alpha3, alpha6, and beta4 were studied in developing and adult human intestine and compared with findings on Ln-alpha1 and Ln-alpha2 chains. In adult human duodenum, jejunum, and ileum, Ln-5 detected with a polyclonal antiserum and Ln-alpha3 and Ln-beta3 chains, detected with monoclonal antibodies (MAbs), were restricted to the epithelial basement membranes (BMs) of villi, whereas Ln-alpha2 chain was seen only focally in crypt bottoms. In double labeling experiments, the stretch of crypt BM corresponding to the proliferative cell compartment was found to be devoid of both Ln-alpha3 and Ln-alpha2 chains. Double labeling for Ln-5 and proliferating cell nuclear antigen also showed an abrupt onset of Ln-5 expression exactly at the upper edge of the proliferative cell compartment. Type VII collagen was negligible in duodenum and showed a rising duodenal-ileal gradient localizing to villar BMs. Double labeling for Ln-5 and Type VII collagen, however, indicated only partial co-distribution in the intestine. Electron microscopy of ileum revealed both anchoring filaments and anchoring fibrils but no hemidesmosomal plaques. Our results demonstrate the expression of Ln-5 in BMs outside of stratified epithelia and indicate that Ln-5 in the intestine is associated with the compartment of migrating and differentiating enterocytes. Absence of hemidesmosomes and the presence of other anchoring complex components, such as Ln-5, Type VII collagen, and integrin chains alpha3, alpha6, and beta4, suggests unique properties for epithelial cell attachment in the intestine.