F. Barberini

Changes in the surface morphology of the rabbit endometrium related to the estrous and progestational stages of the reproductive cycle

SummaryChanges occurring on the surface of the uterine luminal epithelium of the rabbit during the estrous and progestational stages of the reproductive cycle were examined by scanning and transmission electron microscopy. The findings demonstrate that the uterine epithelium, or endometrium, contains two cell types: ciliated cells and nonciliated, microvillous cells. In estrous animals, ciliated cells, although not very numerous, were usually observed in small groups. However, at increasing intervals of time following mating, ciliated cells progressively disappeared from the endometrium until approximately eight to ten days post coitum, when they became scare. From several hours to four to five days following mating, extensive changes occurred on the surfaces of microvillous cells. When observed by TEM, these elements contained organelles typical of cells involved in the synthesis and secretion of glycoproteins. Furthermore, microvillous cells during this period displayed numerous apical protrusions of different sizes and shapes and containing material of varying electron density. Parallel SEM examinations of the same material confirmed the presence of these protrusions. Some of the protrusions appeared as spheroidal masses attached to the cytoplasm by means of a cytoplasmic strand. Other surface masses were clearly unattached to the cell surface and were distributed (1) on the surface of microvillous cells, (2) on the cilia of adjacent ciliated cells, and (3) on the surface of spermatozoa.Changes occurring on the luminal surface during the early postcoital period are interpreted as an expression of morphodynamic processes likely involving coupled secretion (exocytosis) and resorption (endocytosis) of luminal material. The observations presented here also demonstrate that between six and ten days post coitum, the rabbit endometrium contained increasing numbers of enlarged, nonciliated cells that probably arose by the fusion of smaller, microvillous elements.

Vaginal reconstruction by skin grafts: A scanning electron microscopic evaluation*

In order to evaluate the morphofunctional pattern of transplanted skin structural and ultrastructural studies on biopsies taken from surgically created neovaginae in three cases of vaginal agenesis were performed one and two years postoperatively. Two of the cases were associated with a rudimentary uterus, while the remaining one involved testicular feminization. Neovaginae were constructed by directly prolonging a pre-existing perineal introitus, to form a vesicorectal pouch, which was lined inside with gluteal skin autografts. All three patients reported satisfactory psychosexual behavior one year after operation. Light microscopy of the bioptic fragments demonstrated, even two years after surgery, features generally similar to those of the normal dermis and epidermis, and a keratinization rate as a rule, that did not range significantly from the norm. Scanning electron microscopy also confirmed the maturation of the cornified cells, since these were often seen to be desquamating and exhibited structures usually found in normal skin, such as double edges on the luminal surface--usually considered to be the morphological expression of squamous cell overlapping--and microwrinkles on disrupted apical and basal cytoplasmic flaps, which are considered reciprocal cell-gearing devices. Our results seem to indicate, therefore, that the transplanted skin, maintaining, on the whole, its integrity and viability despite an environment differing somewhat from the external one with regard to moisture, pH and temperature, shows a good adaptability, at least until the above mentioned time lapses.

Morphological and statistical investigation of the occurrence of 'tubule-like cells' in the renal corpuscle of the mouse kidney induced by sex hormones.

In this report the authors describe the structural and ultrastructural characteristics of some cells constituting the parietal layer of Bowmans capsule of the mouse kidney, which are very similar to the epithelial cells of the proximal convoluted tubule (tubule-like cells). These elements are noted in mature and immature mice of both sexes, but their fine morphology and statistical incidence seem related to the sex and the age of the mice, as revealed by the different responsiveness of the same animals to sex hormones experimentally administered. Such substances, directly and/or through an influence on gonadotropins (especially luteinizing hormone), are able to modify (mainly increasing) the percentage of renal corpuscles possessing tubule-like cells.

An Ultrastructural Study of Epithelium Differentiation in the Human Fetal Fallopian Tube

The epithelial structure of the developing human fetal Fallopian tube has been studied systematically by parallel light, transmission and scanning electron microscopy. The specimens for this study were collected from spontaneous abortions at the 14th, 18th, 20th and 22nd weeks and from cases of intrauterine fetal death at the 24th and 31st weeks (hydrocephalus). The epithelium lining the wall of the female genital ducts was pseudostratified in a columnar fashion. It consisted of differentiating ciliated and microvillous cells and some degenerating elements. Microvillous cells-by far the most abundant in the early phases of tubal development-often showed a solitary cilium. Ciliated elements, though always less numerous than microvillous cells, were more densely concentrated on the developing fimbriae and at the uterotubal junction than in the ampulla. On the mucosal surface of the same regions, rounded intercellular holes delimited many crypts, from which ciliated elements sometimes sprouted. Notable aspects of cell proliferation and ciliogenesis were commonly observed and are likely to be related to circulating estrogens. These ultrastructural data indicate that the typical pattern of the adult oviduct is already sketched in fetal life. Furthermore, a strategic gathering of cilia was noted primarily at the sites of the developing oviduct, which will serve to mediate the passage of sperm and/or ova and promote fertilization in adult life.

Ultrastructure of Rathke’s pituitary cleft

Rathke’s pituitary cleft represents the original recess of so-called Rathke’s pouch derived in the embryo from the ectodermal evagination of the stomodeum (1,2). In several mammals, for example the rat, dog and cat, this recess persists during postnatal life as a wide fissure separating the pars distalis from the pars intermedia. It is lined by a continuous layer of cells termed ‘marginal cells’, and contains a fluid-like material (colloid) of uncertain function, origin and chemical composition (3).

Columnar cells of the parietal layer of Bowman's capsule and their relationship with the sexual cycle in normal female mice

The tubule-like cells (TLC) are present also in the parietal layer of the Bowmans capsule of the renal corpuscles in normal female mice kidney. These cells are morphologically similar to the cells of the proximal convoluted tubule. Further, significant variations of the TLC were present according to the phase of the sexual cycle.

On a complex arrangement of the vascular pedicle of the left kidney

During the dissection of an 83 year-old male cadaver, we observed that the left renal vein passed behind the aorta to follow an oblique course before draining into the inferior vena cava. The left renal vein was connected to the left suprarenal, spermatic, lumbar ascending and azygos veins. The left spermatic vein, after collecting the suprarenal vein, crossed in front of the abdominal aorta to reach the inferior vena cava directly. Furthermore, the arterial pedicle of the left kidney was composed of two tortuous and intermingled vessels. Variations in the number and arrangement of the vessels terminating in the renal veins are not uncommon, but so complex a vascular arrangement as this has not to our knowledge been previously described. The ontogenetic explanation and clinico-surgical implications of such a variation are reviewed and discussed.

Bifurcation of the left superior pulmonary vein, associated with an anomalous connection with the left atrium

An unusual case of bifurcation of the left superior pulmonary vein (LSPV) just before it enters the pericardium is described. The LSPV, which at the hilus of the lung originated from normal confluence of a superior and inferior root, bifurcated near the left atrium (LAt) of the heart into anterior (AB) and posterior (PB) branches that, separately invaginating the parietal pericardium, formed two individual serous sheaths. The PB coursed almost horizontally and opened, as usual, into the supero-dorsal wall of the LAt. The AB turned downward, reached the superior margin of the left auricle (LAu) and emptied into it. Thus, the AB was interposed between the pulmonary trunk and the LAt, obstructing on the left side the communication between the transverse sinus of the pericardium and the pericardial cavity. The auricular opening of the AB was avalvular, but, unlike those of the normal pulmonary veins (PVs) which are surrounded by a large smooth inner surface, was, except for a narrow smooth-walled zone, close to the pectinate muscles. Moreover, an inferior muscular ridge at the inferior margin of its orifice of entrance into the LAu, separated it from the cavity of the LAt. It is well known that in development the PVs arise from convergence of capillaries belonging to the mediastinal part of the primitive splanchnic plexus and drain this into the systemic (cardinal and vitello-umbilical) veins of the embryo. As a consequence, it might be hypothesized that the AB of the LSPV probably represents a partial remnant either of a pulmonary-cardinal anastomotic mediastinal vein, or of a diverging vessel of the mediastinal plexus from which the PVs originate. In either case the AB became absorbed by the LAu, which, while it was developing on the left side of the primitive truncus arteriosus, drew the AB forward and downward, in the direction of its movement. The influence of such an anomaly of the PVs for altered intracardiac hemodynamics of the oxygenated blood flow has to be emphasized. Furthermore, the particular location of the AB, obstructing the communication between transverse sinus and pericardial cavity, can be a hindrance during cardio-pulmonary surgery.