During folliculogenesis, primary oocytes of teleosts grow by several orders of magnitude by-self synthesizing proteins and mRNA, or sequestering from blood specific macromolecular components, such as fatty acids and vitellogenin. All these materials are stored into cortical alveoli, yolk globules or oil droplets during oocyte development. The proper synthesis, storage and displacement of these macromolecular components inside the oocyte play a key role for a successful fertilization process and for the subsequently correct embryo development. In this study, for the first time, the FTIR Imaging (FTIRI) spectroscopy has been applied to characterize the chemical building blocks of several cellular components of swordfish oocytes at different developmental stages. In particular, the spectral features of previtellogenic (PV), vitellogenic (VTG), mature (M) and atretic (A) follicles as well as and of cortical alveoli (CA), yolk vesicles (YV), oil droplets (OD) and Zona Radiata (ZR) have been outlined, providing new insights in terms of composition and topographical distribution of macromolecules of biological interest such as lipids, proteins, carbohydrates and phosphates. The macromolecular characterization of swordfish oocytes at different developmental stages represents a starting point and a useful tool for the assessment of swordfish egg quality caught in different conditions, such as periods of the year or different fishing area.

The aim was to analyze the morphology of normal human macula densa (MD), evaluate the cells that may be responsible for its turnover, and collect quantitative data. Of four samples of normal human renal tissue, two were embedded in resin to measure the longitudinal extension and examine the ultrastructure of the MD, the other two were embedded in paraffin to study apoptosis and cell proliferation. The MD is composed of a monolayer tissue about 40 μm long, which includes 35-40 cells arranged in overlapping rows. Ultrastructurally, MD cells show two polarized portions: an apical end, with sensory features, and a basolateral aspect, with paracrine function. MD cells are connected apically by tight junctions, with/without adherens junctions, which form a barrier between the distal tubule lumen and the interstitium. Cells in degeneration, often associated with macrophages, and undifferentiated cells were found in the MD and adjacent distal tubule. A filamentous mat previously described in proximal tubule scattered tubular cells (STCs) was detected in the basal cytoplasm in undifferentiated cells. The tissue was consistently negative for the proliferation marker Ki67 and for the apoptotic markers caspase-3 and caspase-9. This work confirms our earlier morphological findings and provides new data: (a) MD cells display both apical adherens and tight junctions, the latter forming a tubulo-mesangial barrier; (b) the MD is a monolayer made up of about 40 cells arranged in rows; (c) the simultaneous presence of degenerating (8-13%) and undifferentiated (4-13%) cells reminiscent of STCs suggests a non-negligible cell turnover.

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To the Editor:We read with great interest the paper by Tubbs et al 1 describing the human indusium griseum (IG) to be a glial membrane above the corpus callosum (CC) without neuronal cells nor connections with the hippocampus. The study, carried out by magnetic resonance imaging and histological and immunohistochemical (ihc) techniques, led the Authors to conclude that transection of this membrane, unavoidable when performing callosotomy (ie, to relieve drug-resistant epilepsy), FIGURE. Sagittal sections of IG. A, B, Staining of IG by Luxol fast blu A and eosin B. The identification of IG is possible thanks to the orientation of its fibers which travel perpendicularly to those of the CC. C, nNOS-positive cells (arrows) are present within the IG, often at the border with CC. Several IG areas contain nNOS-positive nerve fibers (arrowheads). D, NEUN-positive cells are distributed throughout the entire IG (arrows). Scale bars, 100 μm.

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