Archive for the ‘Effects of Injury’ Category

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (9)

Assuming that repair processes have not kept pace with injury, the development of through-and-through septal gaps (ie, pores and fenestrae) might produce more rapid airspace enlargement if they occurred at septal junctions rather than in the alveolar wall between junctions. Retraction of the edges of a gap at the junction of three alveolar walls might […]

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (8)

Because of the striking similarity between papain-induced emphysema and human panlobular emphysema both morphologically and physiologically and the further similarity between normal canine and human lungs in the disposition of interstitial septal gaps, alveolar macrophages and type 2 cells which we have demonstrated, it would seem prudent to study this convenient model further. The complexities […]

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (7)

It appears that the mere presence of neutrophils in the lung does not produce emphysema. On the other hand, MacNee et al, recently reported that cigarette smoking was accompanied by retention of radioactively labelled neutrophils from the lungs of smokers who smoked during their study. Based on experimental studies showing margination of neutrophils preferentially in […]

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (6)

This notion gains credibility from the work of Sage et al confirmed by Lwebuga-Mukasa et al, which showed that type 2 cells in culture produce all of the major protein constituents of the alveolar basement membrane, which is a component of the alveolar septal interstitial matrix. More recently, Crouch et al demonstrated the synthesis of […]

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (5)

Clustering of type 2 cells in alveolar “corners” or septal junctions in mouse lungs has been described previously by Adamson and Bowden. Brains report on lungs fixed by intravascular perfusion shows alveolar macrophages also clustered at the alveolar septal junction. We have shown in previous studies that in normal human lungs preserved by vascular perfusion-fixation, […]

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (4)

On the other hand, the prevalence of gaps in the septal interstitium of the two-week specimen was strikingly increased over that of controls (Fig 4; Table 4). Most of these gaps were occupied by type to severe emphysema which were produced by papain. Gil and Weibel and Brain et al have shown the necessity of […]

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (3)

Transmission Electron Microscopy In all six specimens examined by transmission electron microscopy (control as well as treated), gaps in the interstitium of the alveolar septum of lung alveoli were located predominantly at sites of junctions of alveolar septa and were occupied by type 2 cells (Fig 2 and 3; Table 2). This was especially prominent […]

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (2)

A total of 392 alveoli was reviewed by light microscopy. An average of 106 alveoli per specimen were analyzed in the three control specimens, but only an average of 24 alveoli per specimen which lent themselves to this type of analysis could be identified from the papain-treated specimens.

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Results (1)

Light Microscopy There was an influx of polymorphonuclear leukocytes into the lungs of the 4-h saline and 4-h papain dogs, into all three compartments of the alveolus: the airways, the capillaries and the interstitium. This was more pronounced in the normal saline dog, but prominent also in the 4-h papain dog where it was accompanied […]

Acute and Subacute Effects of Injury on the Canine Alveolar Septum: Methods (5)

Septal continuity, however, was maintained by the alveolar epithelium, usually by a type 2 cell. Less commonly, continuity was maintained by the nucleated portion of a type 1 cell, and least commonly, by a thin single or double layer of type 1 cell cytoplasm. All septal discontinuities, all alveolar macrophages and all epithelial cell types […]

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