Morphology, basement membranes

Fig. 2.14 Cellular morphology of neuroepithelium chemosensory groove in lamellae of the African lungfish Protopterus annectens (Dipnoan) basal, receptor and supporting cells (CB, CRe and CS) MB basement membrane. Owen, x400 (from Derivot, 1984).

In another approach, Parnigotto and coworkers reconstructed corneal structures in vitro by using corneal stroma containing keratocytes to which corneal epithelial cells from bovine primary cultures were overlaid [73], However, this particular corneal model did not contain an endothelial layer. This model was histochemically characterized and the toxicity of different surfactants was tested using MTT methods. This stroma-epithelium model has been reported to show a cornea-like morphology, where a multilayered epithelial barrier composed of basal cells (of a cuboidal shape) and superficial cells (of a flattened shape) is noted. Furthermore, the formation of a basement membrane equivalent and expression of the 64-kDa keratin were reported, indicating the presence of differentiated epithelial cells. The toxicity data for various surfactants obtained with this model correlate well with those seen by the Draize test [73], However, this corneal equivalent was not further validated or used as a model for permeation studies. 

P3h1 mice do not die prematurely but have abnormal collagen fibril morphology in tendon, decreased bone density, and abnormalities in skin and developing limbs lethal at El 1.5 basement membrane is not formed well by electron microscopy... 

Another cause of proteinuria may be damage to the glomerular basement membrane, which can be induced in rats, for example, by the infusion of elastase into the renal artery. In this model, massive proteinuria is not accompanied by any morphological sign of podocyte damage. 

In common with all epithelial interfaces (see Section 1.3.2), the epithelium of the oral cavity is supported by a basement membrane, which separates the epithelium from the underlying connective tissue layer (the lamina propria) (Figure 7.1). Oral epithelium is broadly similar to stratified squamous epithelia found elsewhere in the body, for example the skin (see Section 8.2.1), in that cells are produced by mitosis in the basal layer of the epithelium and these proliferating cells push existing cells towards the surface. The phases of this dynamic process are represented in four morphological layers ... 

Adhesion between cells and to basement membrane Cellular morphology... 

Argani P, Hawkins A, Griffin CA, et al. A distinctive pediatric renal neoplasm characterized by epithelioid morphology, basement membrane production, focal HMB45 immunoreactiv-ity, and t(6 ll)(p21.1 ql2) chromosome translocation. Am J Pathol. 2001 158(6) 2089-2096. 

In order to better understand the pathophysiology associated with these various forms of pulmonary edema, a review of the morphology associated with the capillary-alveolar—intestinal interlace is useful (Fig. 6). From this review it can be seen that fluid in pulmonary capillaries is separated from the alveolar interstitial tissue by the capillary endothelial cells and the capillary basement membrane (commonly called the endothelial barrier). The alveolar surface is separated from the interstitial space by the alveolar-airway barrier, which consists of the alveolar basement membrane, alveolar epithelium, and a layer of pulmonary surfactant within the alveolus. As described previously, the alveolar interstitial tissue is made up of connective tissue (elastin and collagen), fibronectin, and mucopolysaccharides. The interstitial space also contains the pulmonary lympatic system, which functions to drain proteins, large particulate matter, and excess fluid away from the tissue space and to return them to the blood. 

The changes in renal epithelial morphology that accompany acute renal failure are often subtle. At least four cellular fates can be identified in acute renal failure cells may be necrotic cells may become apop-totic they may replicate and divide or they may appear indifferent to the stress (Figure 1). Frank necrosis, as is often seen experimentally, is not prominent in the vast majority of human cases. Necrosis is usually patchy, involving small clusters of cells, sometimes resulting in small areas of denuded basement membrane. Less obvious injury is more often noted, including loss... 

While the binding of fibronectin appears to be a critical feature in the response of cells to many man-made materials, recent studies have shown that treatment of surfaces with other extracellular matrix components, such as laminin and type IV collagen (60), can greatly alter the biological properties of plastics. Treatment of plastic with a biomatrix derived from a basement membrane tumor can alter the morphology and differentiated state of several cell types (60). Hence, the biological properties of polymeric materials are dependent on the type of extracellular atrix molecule absorbed more than the chemical nature of the polymer itself. 

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