Luciano Zamboni

The fine structure of human follicular oocytes

The fine structure of the human oocyte during its maturation in the ovarian follicle was studied in this investigation. Particular emphasis was given to the changes which appeared to take place in the Golgi apparatus of the oocyte during the synthesis and formation of the dense cortical granules and to the fine morphology of the oocyte nucleus during completion of the meiotic division.

Electron microscopic studies on rabbit ova: I. The follicular oocyte

The ultrastructure of the rabbit follicular oocyte prior to maturation and the cytoplasmic changes that characterize oocyte development within the ovarian follicle have been considered. Particular emphasis has been given to the ultra-structure of oocyte meiotic chromosomes in some phases of the first reductional division. Release of the first polar body and the changes undergone by follicular and theca cells during follicular growth have also been evaluated.

A morphologic study of the mesonephros of the human embryo

The fine structure of the mesonephros is studied in 7- and 10-week old human embryos. Marked morphologic differences are observed between the mesonephros and the definitive kidney. These differences relate to the morphology of the afferent and efferent glomerular vessels, endothelial cells of the glomerular capillaries, and epithelial cells of the proximal and distal tubules. The juxtaglomerular apparatus and the Henle loop are absent in the mesonephros. These dissimilarities are evaluated in light of the different functional performances of mesonephros and metanephros.

Electron microscopic studies of blood embryogenesis in humans. I. The ultrastructure of the fetal liver.

The livers of nine human embryos 7–20 weeks of age were studied. Marked differences in the ultrastructure of the liver cells in various phases of development were observed. The ergastoplasmic reticulum appears to undergo structural reorganization about the third month. This occurs simultaneously with the development of the agranular reticulum and the appearance of intracellular glycogen and iron deposits. A full-fledged sinusoidal system is apparent early in development. The reticuloendothelial cells become highly phagocytic in the third month of intrauterine life, as soon as hemopoiesis is initiated in the liver.

Silver methenamine stain for electron microscopy

The results obtained by the application of five different methods to stain with silver methenamine thin sections of tissue for electron microscopy are described and evaluated in this article. Three of these methods lend themselves to wide applications in that they enhance vividly the argentophilic structures without inducing excessive graininess of the staining. The latter appears to be due mainly to prolonged and unnecessary exposure of the sections to the staining solution. The graininess observed in specimens prepared under the most favorable conditions, however, is still too coarse to allow the application of this technique for high resolution electron microscopy.

Electron microscopic studies of blood embryogenesis in humans: II. The hemopoietic activity in the fetal liver

The hemopoietic activity of the fetal liver was studied in nine human embryos 7–20 weeks of age. Hemopoiesis becomes fully established around the third month of intrauterine life. Blood cells originate and mature extravascularly. The various phases of stem cell differentiation along the erythropoietic and thrombopoietic lineages are described. Thrombopoietic differentiation is heralded by the appearance of the first specific granules in the Golgi area of hemocytoblasts. Migration of blood elements in the circulatory stream may occur in various phases of the differentiative process.

An interpretation of the structural changes responsible for the chronicity of rhinoscleroma.

Objective To identify the structural changes of the proliferative phase of rhinoscleroma which could be responsible for the chronicity of the disease.

A re-evaluation of the mesangial cells of the renal glomerulus

SummaryThe topographical localization of the mesangial cells in renal glomeruli of rats, and their relationships with the structures at the hilus of the glomerulus were studied in this investigation. It was observed that the mesangial cells occupy a parietal position in the wall of the glomerular capillaries, and that they are anatomically continuous with the smooth muscle cells of the tunica media of the glomerular arterioles.

Fine morphology of regressing human mesonephric nephrons

Abstract The changes which characterize the involution of human mesonephric nephrons have been studied by means of light and electron microscopy. The most salient glomerular changes appear to be modifications of the mesangial cells and other components of the capillary wall, resulting in progressive reduction and eventual obliteration of the vascular bed of the glomerulus; tubular changes are essentially characterized by severe epithelial cell degeneration and the presence of pleomorphic luminal casts. The possible mechanisms responsible for the regression of the human mesonephros are discussed together with an evaluation of the analogies between the glomerular and tubular changes accompanying the regression of mesonephric nephrons and those occurring in the nephrons of the definitive (metanephric) kidney in a wide variety of pathologic conditions.