Reflection imaging of China ink-perfused brain vasculature using confocal laser-scanning microscopy after clarification of brain tissue by the Spalteholz method.

Confocal laser-scanning microscopy is a useful tool for visualizing neurons and glia in transparent preparations of brain tissue from laboratory animals. Currently, imaging capillaries and venules in transparent brain tissues requires the use of fluorescent proteins. Here, we show that vessels can be imaged by confocal laser-scanning microscopy in transparent cortical, hippocampal and cerebellar preparations after clarification of China ink-injected specimens by the Spalteholz method. This method may be suitable for global, three-dimensional, quantitative analyses of vessels, including stereological estimations of total volume and length and of surface area of vessels, which constitute indirect approaches to investigate angiogenesis.

Morphocytochemical, immunohistochemical and ultrastructural characterization of the head kidney of fat snook Centropomus parallelus.

This study characterized the structure and the morphocytochemical, immunohistochemical and ultrastructural aspects of the head kidney (HK) of the fat snook Centropomus parallelus. The HK is enclosed by a thin capsule of connective tissue, from which fine trabeculae originate and branch into the interior of organ. In the parenchyma, there are aggregates of lymphoid cells containing populations of lymphocytes T immunopositive for CDRO45, in a nodular arrangement, around blood vessels and melano-macrophage centres. Among the cells that constituted these aggregates and surrounded them, were macrophages and monocytes, and their precursors, with strong immunopositivity for CD68, along with cells of the granulocytic lineage in various phases of maturation positive for lysozyme and PAS. Macrophages and chromaffin and interrenal cells are also present. Ultrastructurally, the HK comprises a reticulum-endothelial stroma consisting of endothelial cells, reticulocytes of the fibroblast type and macrophage type and a parenchyma with increased cellularity, principally blood cells of the erythrocytic, granulocytic, lymphocytic, monocytic and thrombocytic series.

Rudimentary eyes of squamate fossorial reptiles (Amphisbaenia and Serpentes)

The rudimentary characteristic of the eyes of fossorial animals raises some questions regarding its evolution and functionality. Would these eyes result from atrophy or from stagnated development? How would its visual function work? Anatomical investigations of these organs are the fundamental preamble to answer those questions, which are still little explored by the literature. In this article we have studied anatomical aspects of the eyes of three species of fossorial reptiles, within the suborder Amphisbaena (Amphisbaena alba, Amphisbaena mertensi, Leposternon infraorbitale), as well as a species within the ophidian suborder (Typhlops brongersmianus). The minuscule eyes (1-2 mm diameter) were visualized through a scale, a translucent area which corresponds to the spectacle. This spectacle is a thinner and transparent scale, covering a conjunctival sac. The retrobulbar space was filled with the harderian gland. The eyes of Typhlops presented an oval shape, whereas Amphisbaena specimens presented cup-shaped eyes. In Amphisbaenian sclera is comprised of cartilage, while the thin sclera of Typhlops consists of connective tissue and striated muscle fibers. The retina presented all the typical layers found in vertebrates, regardless the species. The characteristics involved in the fossil adaptation of these species include: reduced size of the eyeball, rudimentary cornea, absence of the anterior chamber, presence of a complex iris-ciliary body, and lens with amorphous nucleate cells. The analysis of the eye morphology of these animals suggests that there might be a specific function concerning light perception.