Acute and Subacute Effects of Injury on the Canine Alveolar Septum (2)
In addition, increased amounts of oxygen radicals and peroxidase which can inactivate alpha-1 proteinase inhibitor or alpha-2 macroglobulin, another proteinase inhibitor, have been found in alveolar macrophages. Finally, cigarette smoke has been reported to stimulate cathepsin-B activity in the alveolar macrophages of rats. Cathepsin-B is one of the major enzymes with elastolytic activity produced by alveolar macrophages. The degradation of elastin fibrils in the lung parenchyma by elastases, of course, is widely supposed to cause the destructive changes associated with pulmonary emphysema.
One objective then of this study was to determine if there was any morphologic evidence in the canine lung placing alveolar macrophages in the vicinity of possible early interstitial damage. buy ampicillin
On the repair side of the equation, ever since the reports of Kapanci et al, Evans et al and Adamson and Bowden, it generally has been accepted that the type 2 cell, in addition to producing lung surfactant, is the progenitor of the type 1 cell. Recently, reports by Lwrebuga-Mukasa et al and Crouch et al have indicated that the type 2 cell also is capable of producing, at least in vitro, all of the major protein constituents of the basal lamina, a component of the interstitium of the alveolar septum. This suggested the hypothesis that the type 2 cell plays a role in alveolar septal repair which goes beyond that of merely replacing injured or killed type 1 cells. The present study was undertaken in part also to see if there was any morphologic evidence in the experimental canine emphysema model which might suggest support for this hypothesis.