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M Castellucci

Publications and source records attributed to M Castellucci.

50 records · Page 3Linked to original sources
PubMed1984

The stromal architecture of the immature intermediate villus of the human placenta. Functional and clinical implications.

Scanning electron microscopy of cryofractured immature intermediate villi showed numerous intercommunicating channels in the central region of the stroma, oriented mostly parallel to the major axis of the villus. In the stromal channels, numerous Hofbauer cells were present and their aspect and position inside the channels highly suggested a motility of these cells. These morphological data strongly support the fundamental role played by the immature intermediate villus in the normal and pathological development of the human placenta.

Cell Differentiation↗
PubMed1982

Monilethrix. Comparative scanning electron microscopic study of the hair in one family.

A comparative examination of the hair of the members of a family with monilethrix was carried out. Scanning electron microscopy (SEM) was used in the examination. It could be shown that the hair of persons with monilethrix showed a clear irregularity in its surface structure. A corresponding pattern was found in the clinically healthy sister and the likewise healthy father. The surface of the mother's hair showed a normal condition. The cuticle of the monilethrix appears to be very soft. The SEM method permits more exact examinations concerning the heredity of monilethrix.

Adult↗
PubMed1981

The brush cells of the common bile duct of the rat. This section, freeze-fracture and scanning electron microscopy.

Two different fixative procedures (immersion and perfusion) and four different fixative solutions were used in order to obtain the best preservation of the brush cells of the common bile duct of the rat. The results indicate that only perfusion fixation through the common bile duct is suitable, independent of the fixative solutions and their osmolarity. Numerous brush cells were seen in the proximal and distal regions of the common bile duct. In these locations, they could be implicated in a registration and/or regulation of intraluminal pressure variations.

Animals↗
PubMed1980

A three-dimensional study of the normal human placental villous core. I. The Hofbauer cells.

In order to study the three-dimensional ultrastructure of the Hofbauer cells, human placentae from the 6th to the 21st week of gestation and also from the end of pregnancy were cryofractured and observed by scanning electron microscopy. Hofbauer cells were found in the villous core at all the gestation stages examined. Their surface morphology was characterized by lamellipodia, funnel-like structures, blebs and microplicae. This pleomorphic aspect was probably related to functional or environmental conditions. In addition, thin cytoplasmic processes connected the Hofbauer cells with each other and with the components of the villous stroma. Fractured Hofbauer cells revealed large vacuoles in the cytoplasm; the vacuoles were smaller in size both at the beginning and at the end of pregnancy. This study further attests to the macrophagic nature of these cells.

Chorionic Villi↗
PubMed1978

[The structure of the round window membrane studied by thin section.- freeze-fracture- and scanning electron microscopic technique (author's transl)].

In thin sections of the round window membrane of chinchilla there were found tight junctions between the cells of the outer and of the inner cell layer as well. Their structure was demonstrated in freeze-fracture replica, and in the scanning electron microscope both faces of the membrane appeared uninterrupted. The tight junctions between the mucosal cells constantly became visible and are considered impermeable; however, the junctions connecting the mesothelial cells, which face the perilymph, demonstrated high susceptibility against differences in preparation and were structurally different.

Animals↗
PubMedDate not supplied

Mitosis of the Hofbauer cell: possible implications for a fetal macrophage.

Human chorionic villi from placentae collected during the first half of pregnancy were examined by light microscopy and transmission electron microscopy. In serial semithin sections mitoses of Hofbauer cells, as well as those of other cellular components of the villous stroma, were generally easily identified. In some cases, when the Hofbauer cells showed very few vacuoles, thin sections were helpful in differentiating this cell type from the fixed stromal cells. Hofbauer cells in mitotic division were not uncommon, but were irregularly distributed. Mitosis of the Hofbauer cells could be a mechanism involved in maintaining the permanent presence in the chorionic villi of cell subpopulations with different origins and functions. Another explanation for the mitotic division of these cells could be that they are a self-renewing population independent of fetal monocytes which appear later in gestation in chorionic villi. In addition, mitosis of the Hofbauer cells could allow a rapid increase in their numbers when required by the local microenvironment.

Chorionic Villi↗
PubMedDate not supplied

Branching patterns of human placental villous trees: perspectives of topological analysis.

Topological analysis was applied to investigate the branching pattern of three specimens obtained from early human placenta (6, 9, and 16 weeks p.m.) reconstructed on the basis of semi-thin sections. Centripetal Horton-Strahler and centrifugal branching order nomenclature was used for topological description of the analysed tree-like structures. Bifurcation ratio and vertex ratio were determined for all three cases and were found to be relatively constant. It was shown that branching pattern is closely related to the model of random segment branching that implicates a high level of asymmetry and a small level of space limitation for branching. The significance of this approach for the analysis of development of the villous tree, for the analysis of mesenchymal villous heterogeneity, and for the estimation of physiological parameters for fetoplacental exchange is discussed. We suggest that topological analysis can lead to a new quantitative classification of branching patterns of the human placental villous trees in normal and pathologic pregnancies.

Chorionic Villi↗
PubMedDate not supplied

A three-dimensional study of the normal human placental villous core: II. Stromal architecture.

The three-dimensional architecture of the villous core of the chorionic villi has been studied in the human placenta throughout pregnancy by scanning electron microscopy, and compared with light microscopic and transmission electron microscopic, findings. Five different types of villi are recognizable: the mesenchymal villi are characterized by a network of tiny bundles of collagen fibrils, enmeshing mesenchymal cells, Hofbauer cells and vessels. The immature intermediate villi display a system of intercommunicating channels, parallel to the major axis of the villi. Within the channels, Hofbauer cells are present. The mature intermediate villi show narrow and short stromal channels, surrounded by a rather tight network of collagen fibrils. Large vessels and a highly compact network of collagen are typical of the stem villi. The terminal villi contain sinusoidally dilated capillaries and a small amount of connective tissue. These findings have numerous functional implications. They are particularly related both to the presence of the stromal channels which could facilitate the macrophagic and immunological task of the Hofbauer cells, and to the different types of villi, playing different roles in placental and fetal life, under normal and pathological conditions.

Chorionic Villi↗
PubMedDate not supplied

Villous sprouting: fundamental mechanisms of human placental development.

There is increasing evidence that maldevelopment of the placental villous tree can play an important role in the pathogenesis of various pregnancy diseases. In this review we present the most recent advances of cellular and molecular mechanisms involved in the early formation of chorionic villi. In particular we focus our attention on the structural events during early villous sprouting leading to the formation of the mesenchymal villi which are the forerunners of all other villous types, i.e. immature intermediate villi, stem villi, mature intermediate villi and terminal villi. Early villous sprouting starts as 'hot spots' which are circumscribed areas consisting of highly proliferating cytotrophoblastic and stromal cells. The post-proliferative cytotrophoblastic cells fuse with the overlying syncytium leading to the formation of the trophoblastic sprouts. When villous mesenchyme invades the trophoblastic sprouts, the latter are transformed into villous sprouts. The vascularization of the villous sprouts leads to the formation of the mesenchymal villi, the most basic villous type. This process is repeated throughout pregnancy. We analyse the influence of various extracellular matrix molecules, e.g. tenascin and hyaluronic acid, on the formation of hot spots and mesenchymal villi as well as the transformation of the latter in other villous types. We present a critical survey on the data on vessel formation related to villous sprouting and morphogenesis of mesenchymal villi as well as the expression of various angiogenic factors and their receptors.

Chorionic Villi↗