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Presents a study which performed electrochemical and spectroscopic measurements to characterize the electrochromic behavior of sputtered vanadium pentoxide films. Experimental procedures; Results and discussion; Conclusions.

Abstract: Laminins are a major component of basement membranes. Each laminin molecule is a heterotrimeric glycoprotein composed of one α, one β, and one γ chain. Fifteen laminin isoforms exist, assembled from various combinations of 5α, 3β, and 3γ chains. The embryonic lung has abundant laminin isoforms. Increasing evidence suggests that different laminin isoforms have unique functions in lung development. Studies of embryonic lung explants and organotypic co-cultures show that laminin α1 and laminin 111 are important for epithelial branching morphogenesis and that laminin α2 and laminin 211 have a role in smooth muscle cell differentiation. In vivo studies of laminin α5-deficient mice indicate that this laminin chain, found in laminins 511 and 521, is essential for normal lobar septation in early lung development and normal alveolization and distal epithelial cell differentiation and maturation in late lung development. However, not all of the laminin chains present in the developing lung appear to be necessary for normal lung development since laminin α4 null mice do not have obvious lung abnormalities and laminin γ2 null mice have only minimal changes in lung development. The mechanisms responsible for the lung phenotypes in mice with laminin mutations are unknown, but it is clear that multiple laminin isoforms are crucial for lung development and that different laminin isoforms exhibit specific, non-overlapping functions. [Copyright &y& Elsevier]

Background: Laminin γ2 (Lamc2), one of the polypeptides in laminin-332 (laminin-5), is prominent in the basement membrane of alveolar walls and airways of developing and adult lung. Laminins are important for lung morphogenesis and based on its localization, a function for laminin γ2 in lung development has been hypothesized. Targeted deletion of the laminin γ2 gene in mice results in skin blistering and neonatal death at 3-5 days after birth due to failure to thrive. Methods: Examination of lung development in Lamc2-/- mice through 1-2 days postnatal was accomplished by morphometric analysis, lung bud culture, electron microscopy, immunohistochemical and immunofluorescence staining. Results: Compared to littermate controls, Lamc2-/- lungs were similar in morphology during embryonic life. At post-natal day 1-2, distal saccules were mildly dilated by chord length measurements. Epithelial differentiation as evaluated by immunohistochemical staining for markers of ciliated cells, Clara cells, alveolar type I cells and alveolar type II cells did not reveal a difference between Lamc2-/- and littermate control lungs. Likewise, vascular development, smooth muscle cell differentiation, and elastic fiber formation looked similar, as did airway basement membrane ultrastructure. Branching morphogenesis by lung bud culture was similar in Lamc2-/- and littermate control lungs. Since laminin-332 is important for hemidesmosome formation, we examined the structure of tracheal hemidesmosomes by transmission electron microscopy. Compared to littermate controls, Lamc2-/- tracheal hemidesmosomes were less organized and lacked the increased electron density associated with the basement membrane abutting the hemidesmosome. Conclusion: These findings indicate that laminin γ2 and laminin-332, despite their prominence in the lung, have a minimal role in lung development through the saccular stage. [ABSTRACT FROM AUTHOR]

Abstract: Laminin α5 is prominent in the basement membrane of alveolar walls, airways, and pleura in developing and adult lung. Targeted deletion of laminin α5 in mice causes developmental defects in multiple organs, but embryonic lethality has precluded examination of the latter stages of lung development. To identify roles for laminin α5 in lung development, we have generated an inducible lung epithelial cell-specific Lama5 null (SP-CLama5 fl/−) mouse through use of the Cre/loxP system, the human surfactant protein C promoter, and the reverse tetracycline transactivator. SP-CLama5 fl/− embryos exposed to doxycycline from E6.5 died a few hours after birth. Compared to control littermates, SP-CLama5 fl/− lungs had dilated, enlarged distal airspaces, but basement membrane ultrastructure was preserved. Distal epithelial cell differentiation was perturbed, with a marked reduction of alveolar type II cells and a virtual absence of type I cells. Cell proliferation was reduced and apoptosis was increased. Capillary density was diminished, and this was associated with a decrease in total lung VEGF production. Overall, these findings indicate that epithelial laminin α5, independent of its structural function, is necessary for murine lung development, and suggest a role for laminin α5 in signaling pathways that promote alveolar epithelial cell differentiation and VEGF expression. [Copyright &y& Elsevier]

Laminin α/β/γ heterotrimers are the major noncollagenous components of all basement membranes. To date, five α, three β, and three γ chains have been identified. Laminin α5 is expressed early in lung development and colocalizes with laminin α1. While laminin α1 expression in the lung is restricted to the embryonic period, laminin α5 expression persists throughout embryogenesis and adulthood. Targeted mutation of the mouse laminin α5 gene Lama5 causes embryonic lethality at E14–E17 associated with exencephaly, syndactyly, placentopathy, and kidney defects, all attributable to abnormal basement membranes. In this investigation, lung development in Lama5−/− mice up to E16.5 was examined. We observed normal lung branching morphogenesis and vasculogenesis, but incomplete lobar septation and absence of the visceral pleura basement membrane. Preservation of branching morphogenesis was associated with ectopic deposition of laminin α4 in the airway basement membrane. Perturbation of pleural basement membrane formation and right lung septation correlated with absence of laminin α5, which was found to be the only laminin α chain present in the normal visceral pleura basement membrane. Our finding of normal lung branching morphogenesis with abnormal lobar septation demonstrates that these processes are not obligatorily linked. [Copyright &y& Elsevier]

Examines the role of MLE-15 respiratory epithelial cells in laminin α-chain expression. Production of laminin-α5 by MLE-15 cells; Induction on the expression of laminin-α1 by the transforming growth factor-Β1; Causal factor for the layer assembly of MLE-15 cells.

The article discusses a phylogenetic analysis on dengue virus (DENV) serotype 2 Cosmopolitan genotype in Ho Chi Minh, Vietnam. The study explored DENV lineages circulating in Ho Chi Minh City using samples from dengue patients in research studies at the Hospital for Tropical Diseases from 2017-2022 and it estimated ancestral node locations via root-to-tip regression analyses. It examined the dynamics of DENV prevalence, spread and transmission within Vietnam.