A new method for the joint visualization of vascular structures and connective tissues: Corrosion casting and 1 N NaOH maceration

Corrosion casting combined with scanning electron microscopy (SEM) has been widely used to study the morphofunctional aspects of microcirculation in many organs. In this study, we present an optimization of the corrosion casting (CC) technique associating it with NaOH 1 N maceration method to obtain a clear visualization of the relationships existing between the microvascular architecture of an organ and its extracellular matrix. Briefly, experiments were performed macerating the tissue previously injected with a low viscosity acrylic resin in 1 N NaOH and then observing it at SEM. In this study, we present an application of this technique to better evaluate the extracellular components of the vascular wall in medium-sized and capillary vessels both in skin and in kidney. The results obtained yielded clear images of the three-dimensional layout of medium-sized and capillary vessels in comparison with the extracellular environment. Furthermore, detailed information was obtained on the three-dimensional layout of fibers constituting the walls of venules, arterioles, and capillaries. In addition, the tubular collagenic structures surrounding the excretory tubules of the kidney and the dermal glands of the skin were depicted and their relationships with their vascular supply described in detail. © 2006 Wiley-Liss, Inc

The shape modulation of osteoblast-osteocyte transformation and its correlation with the fibrillar organization in secondary osteons: a SEM study employing the graded osmic maceration technique

Cortex fractured surface and graded osmic maceration techniques were used to study the secretory activity of osteoblasts, the transformation of osteoblast to osteocytes, and the structural organization of the matrix around the cells with scanning electron microscopy (SEM). A specialized membrane differentiation at the base of the cell was observed with finger-like, flattened processes which formed a diffuse meshwork. These findings suggested that this membrane differentiation below the cells had not only functioned in transporting collagen through the membrane but also in orienting the fibrils once assembled. Thin ramifications arose from the large and flat membrane foldings oriented perpendicular to the plane of the osteoblasts. This meshwork of fine filaments could not be visualized with SEM because they were obscured within the matrix substance. Their 3-D structure, however, should be similar to the canalicular system. The meshwork of large, flattened processes was no more evident in the cells which had completed their transformation into osteocytes

Do superficial epigastric veins of rats have valves?

The rat is a good model for experimental studies on the haemodynamic patterns of free-flap transfer but models involving the superficial epigastric vein have not been supported by the demonstration of the anatomical presence or absence of valves inside it. We performed a morphological study to assess whether or not valves are present inside the superficial epigastric vein of the rat. Segments of superficial epigastric veins were explanted from fifteen Sprague-Dawley rats. The lumen was studied with scanning electron microscopy after longitudinal or transverse incision of the venous walls. No valves were detected and we saw no evidence of their accidental removal. As most human veins do have valves, the clinical implications of haemodynamic data on reverse-flow island flaps obtained in rats must be considered very carefully