[Histochemical study of elastic system fibers of the walls of normal and pathological saphenous veins]. / Etude histochimique des fibres du système élastique dans les parois des veines saphènes normales et pathologiques.

Normal, varicose and phlebitic saphenous veins were studied by histochemical methods to establish the qualitative variations of their structural components. The histologic preparations were stained by hematoxylin-eosin Gomori's trichrome, orcinol-neofuchsin and resorcin-fuchsin. Normal saphenous vein showed two layers of smooth muscle cells--an internal circular and an external longitudinal. The components of the elastic system were found in the three layers. Elastic fibers were present in the adventitia under an elongated and wavy conformation. In the media they were present in the external portion. Elaunin fibers were found in the media and intima. The oxytalan fibers were not consistently found. The media and intima of varicose veins showed contracted smooth muscle cells associated with fragmented elastic fibers and augmentation of elaunin fibers. In cases of thrombophlebitis the same alterations observed in varicose veins were found together with a decrease of elastic system fibers in the media and intima. The muscle cells showed a loss of their morphologic characteristics.

Elastic-related fibers in the annular ligament of the stapes-oval window articulation. An electron microscopic and histochemical study in the rat and the rabbit.

The annular ligament that attaches the circumference of the base of the stapes to the margin of the oval window (fenestra vestibuli) was stained with selective methods for elastic system fibers and was also studied at the ultrastructural level after tannic acid-glutaraldehyde fixation. Although the annular ligament is devoid of elastic fibers, it is rich in elastic-related fibers (i.e. = oxytalan and elaunin fibers). Elaunin fibers predominate in the annular ligament itself and they are continuous with the oxytalan fibers which are embedded in the matrix of the articular cartilage.

Distribution of elastic system fibers in hyaline and fibrous cartilages of the rat.

Rat hyaline and fibrous cartilages whose glycosaminoglycans had been removed by hyaluronidase digestion were studied by comparing the ultrastructural features with the observation of sections stained by selective methods for elastic system fibers under the light microscope. Except for the fibrous layer in the perichondrium of tracheal hyaline cartilage, where elastic fibers were found, no elastic fibers could be detected in the cartilages studied. However, cartilaginous tissues contained oxytalan and elaunin fibers. A distinct pattern of distribution of the above-mentioned elastic-related fibers could be observed in both kinds of cartilages. Hyaline cartilages possess oxytalan fibers in the extracellular matrix that surrounds the chondrocytes, whereas elastic fibers were localized in the fibrous layer of the perichondrium that encloses the cartilage. Elaunin fibers could be detected in the transition (chondrogenic) layer adjacent to the perichondrium. The methods used disclosed the presence of oxytalan and elaunin fibers running along the periphery of the collagen bundles in fibrocartilage.

Studies of morphologically atypical ("sprouting") cultures of bovine aortic endothelial cells. Growth characteristics and connective tissue protein synthesis.

Morphologic and biochemical studies were performed on cultures of bovine aortic endothelial cells which had developed a second growth pattern that has been referred to as "sprouting" (Gospodarowicz and Mecher, '78; Schwartz '78). These morphologically atypical cells undergrew the intact endothelial cell monolayer and appeared only after the cells had reached confluence. They were ultrastructurally very similar to endothelial cells, but synthesized reduced amounts of fibronectin and a predominance of type I procollagen, rather than the types III and IV procollagens synthesized by monolayer endothelial cells. It is suggested that these cells represent phenotypically altered endothelial cells that differ in biosynthesis of secreted proteins and display a reduced contact-inhibition.

Oxytalan fibers in the Schistosoma mansoni tegument.

In order to elucidate the nature of the fibrous network present in Schistosoma mansoni tegument, adult worms were studied by light and electron microscopy. It was suggested that this network is formed by bundles of tubular microfibrils 10--12 nm in diameter, similar to oxytalan microfibrils present in higher animals.

Connective fibers involved in the dermoepidermal anchorage. An electron microscopical study.

The human dermoepidermal anchoring fibrils, the oxytalan fibers and the elaunin fibers have been related with dermoepidermal adherence. In the present work their ultrastructure and origin are studied. The similarity between the segment longspacing tropocollagen molecular aggregates and the anchoring fibrils band patterns is evidenced. This fact supports the concept that the anchoring fibrils may be formed by a mechanism of side by side tropocollagen molecular aggregation after its polar binding to the basement lamina. The oxytalan fibers were studied in the superficial dermis, and their direct continuity with the elaunin fibers was demonstrated. The role of these fibers in the dermoepidermal mechanical adhesion is discussed.

The elastic system fibers.

Using the tannic acid-glutaraldehyde fixation it was possible to clearly visualize, with reproducible results, the elastic fiber amorphous material because of its density. The microfibrillar component was also evidenced with a good performance. With this technique the ultrastructural patterns of the oxytalan and elaunin fibers were also demonstrated. The oxytalan fibers appeared as a bundle of microfibrils similar to elastic microfibrils without amorphous material. The elaunin fibers presented a dispersed amorphous material intermingled among the microfibrils. It was suggested by ultrastructural evidences that oxytalan and elaunin fibers may represent interruption in successive phases in the development of the elastic fibers.

Oxytalan, elaunin, and elastic fibers in the human skin.

The elastic system of normal human skin was studied by light and electron microscopy. By light microscopy three different types of fibers were observed: oxytalan, elaunin, and elastic. The most superficial ones (oxytalan fibers) are very thin and directed perpendicularly to the dermoepidermal junction. They start from a plexus with the tinctorial characteristics of elaunin fibers which is connected with the thicker elastic fibers of the reticular dermis. At the electron microscopic level the oxytalan fibers are formed by bundles of tubular microfibrils 10 to 12 nm in diameter. In the deepest layers of the dermis an amorphous material is seen in the core of these bundles. In the elaunin fibers the amorphous material is sparse, while in the elastic fibers it is abundant and compact.

The use of tannic acid-glutaraldehyde in the study of elastic and elastic-related fibers.

Fixation with tannic acid-glutaraldehyde permits distinction of oxytalan, elaunin and elastic fibers in the electron microscope. The results obtained using tannic acid at concentrations of 1.0%, 0.5% and 0.25% in 3% glutaraldehyde were compared. The 0.25% concentration is recommended for studying fine details of connective fibrils and for regular staining of elastin.

Ultrastructural study of elaunin fibres in the secretory coil of human eccrine sweat glands.

The basement membrane of the secretory coil of human eccrine sweat glands was studied by light and electron microscopy. With classical staining methods for the elastic system, elaunin ring fibres were observed in the basement membrane of the secretory coil. The ultrastructural study showed that elaunin fibres are formed by bundles of fibrotubules 10-12 nm in diameter surrounding aggregates of amorphous material. These fibres differ from elastic fibres which are thicker and have an amorphous material more homogeneous and abundant.

The fine structure of the elastic tendons in the human arrector pili muscle.

The elastic tendons by which the arrector pili muscle is inserted into the hair follicle were studied by light and electron microscopy. From the follicle to the muscle it was observed that these tendons are formed successively by oxytalan, elaunin and elastic fibres. In close contact with the smooth muscle cells, elaunin and elastic fibres were observed. The fibres penetrate the spaces between the muscle cells and are clamped by them. An explanation is advanced about the significance of this arrangement in the recovery after muscle contraction.