The three-dimensional architecture of the myosalpinx in the rat (Rattus norvegicus) as revealed by scanning electron microscopy.

The three-dimensional (3-D) architecture of myosalpinx in the rat has been investigated by means of scanning electron microscopy after microdissection and removing interstitial connective tissue with 6N NaOH digestion. In the extramural portion of tube-uterine junction the myosalpinx shows circularly arranged fibers originating from the uterus, together with oblique fibers typical for the salpinx, which occur more frequently in the deeper layers. As fibers approach the mucous folds they assume a plexiform arrangement, which is maintained through all tubal segments. In the isthmus surface fibers form wide muscle rings around the elbow of loops, peculiar to the rat tubal morphology. Surface fibers in the ampulla and pre-ampulla have an even circular course. Our 3-D results reveal that the muscular architecture of rat tube is mainly organized in concentric, monolayered shells with a plexiform arrangement tightly fastened together. Functionally, this muscular arrangement seems to be capable of stirring rather than pushing the embryo and gametes. Finally, such a plexiform network might work as a mechanism of "tube locking" in proximity of isthmic loops as well as at the level of the ampullary-isthmic junction.

A new morphological classification during follow-up in patients with celiac disease: a three-dimensional observation by scanning electron microscopy.

The structure and ultrastructure of the villi of small intestinal mucosa was examined in 237 duodenal or jejunal biopsies taken from children with active celiac disease and during gluten-free diet. All biopsies were processed for light and scanning electron microscopy. Conventional histology showed four different morphological aspects: total and subtotal villous atrophy in patients on unrestricted diet, partial villous atrophy and normal mucosa during gluten-free diet. Scanning electron microscopy demonstrated that in active celiac disease the severity of the intestinal lesions was related to individual vulnerability to gluten. Our results showed that during dietary treatment the process of mucosal healing was constant and strictly time-dependent. Furthermore, the ultrastructural examination has been relevant in evaluating the evolution of the villous regeneration. In this study a classification regarding the healing process of the small intestinal mucosa correlated with the time of start of dietary therapy is proposed.

Histology of the exocrine pancreas.

The morphology of the exocrine secretory unit of the pancreas, i.e. the pancreatic acinus, is reviewed. The histological features of the acini and their relation with the duct system are described. The acinar three-dimensional architecture was studied by means of different ultrastructural techniques, some of which are complementary. The fine structure and morphodynamics of the acinar cells are also described. In addition, the location of the organelles in specific cytoplasmic domains and their close morphofunctional relationship with the sequential stages of secretion of the digestive enzymes are specially emphasized. Finally, morphological approaches are suggested to achieve a better comprehension of the physiological and pathological pancreatic activities whose morphodynamics need to be further elucidated or are almost totally unknown.

The collagen skeleton of the human umbilical cord at term. A scanning electron microscopy study after 2N-NaOH maceration.

The organization of the collagen fibrils in the human umbilical cord at term is directly visualized by means of a scanning electron microscopy cell maceration method. This technique clearly reveals that there is a much more extensive collagen fibrillar architecture within the umbilical cord than that reported in the classical histological descriptions. The Wharton's jelly, in fact, appears as a spongy network of interlacing collagen fibres and small woven bundles apparently arranged at random and forming a continuous soft skeleton that encases the umbilical vessels. The collagen fibrillar network shows the presence of a wide system of interconnected cavities consisting of canalicular-like structures as well as cavernous and perivascular spaces. This system of cavities might play a mechanical role allowing the storing of the ground substance of the jelly and its diffusion during twisting or compression. Furthermore, it may have an important role facilitating the diffusion throughout the jelly of diffused materials (i.e. water and trophic metabolites) either from or to the umbilical vessels and the amniotic cavity, thus overcoming the lace of a proper vasculature with the jelly.

The mucosa of the rabbit vagina: a proposed experimental model for correlated morphofunctional studies in humans.

In order to suggest a valid experimental model for correlated studies regarding the complex phenomena of reproductive biology in humans, light (LM), transmission (TEM) and scanning electron microscopic (SEM) observations were carried out on vaginae of sexually mature New-Zealand albino rabbits, both in estrus and at 5 h after mating. To avoid artifacts depending upon the operative times for specimen removal and, in particular, to well visualize the inner surface of this organ, vaginal irrigation with fixative was performed prior to the surgical removal. Our data demonstrate that the upper 2/3 of the vaginal duct form a kind of 'cervico-vaginal canal' which shares many histological features with the human endocervix. In fact, this portion is lined within by a monostratified epithelium provided with tall microvillous and ciliated cells and often invaginated in crypts. After mating, the microvillous cells showed evidence of secretory activity, exhibiting dome-like luminal surfaces. Secretory droplets often contacted cilia and spermatozoa present in the mucosal furrows and crypts. Because of these singular features and the morphofunctional interactions between vaginal epithelium and male gametes, we believe the rabbit to be a helpful model for comparative biology in humans, concerning sperm capacitation and the general reactivity of the female genital tract during the reproductive cycle.

The architecture of the myosalpinx in the sow as revealed by scanning electron microscopy.

OBJECTIVE: To provide a definitive settlement of data on the architecture of myosalpinx in the sow in consideration of controversial data existing in literature. STUDY-DESIGN: To allow direct visualization of muscular architecture, segments of tube from fifteen sows were investigated by means of scanning electron microscopy after the removal of interstitial connective tissue with NAOH digestion. RESULTS: In the extramural portion of the tubo-uterine junction, in the isthmus and ampulla, the myosalpinx is mainly constituted by oblique bundles of variable length, which run around the tube and merge into the surrounding musculature, giving origin to a plexiform arrangement. In the ampulla the fibers join in short bundles variously oriented. CONCLUSION: The three-dimensional architecture of the sow myosalpinx consists of muscular bundles independent of one another which follow multiple spatial arrangements and form a complex network. Such a muscular structure is likely more suitable for stirring rather than pushing the embryo and gametes.

The three-dimensional architecture of the myosalpinx in the rabbit as revealed by scanning electron microscopy.

The three-dimensional (3-D) architecture of the myosalpinx in the rabbit has been investigated by means of scanning electron microscopy after microdissection and the removal of interstitial connective tissue with KOH digestion. In the extramural portion of the tubo-uterine junction, the myosalpinx presents outer longitudinal bundles which form a well-defined continuous muscular layer extending towards the ampulla. Underlying this layer there are single muscular bundles which follow an uneven circular arrangement. At a deeper level the same bundles present a plexiform arrangement. Several bundles reach the base of the mucous folds and follow a discontinuous, approximately longitudinal arrangement. In the isthmus, the myosalpinx shows superficial longitudinal strips that abruptly bend sideways as they approach the ampulla, thereby enveloping the underlying muscular structure. The latter is arranged in the same way as at the extramural portion of the tubo-uterine junction, except for the lack of the outer longitudinal layer originating from the uterus. Our 3-D results revealed that the architecture of the rabbit myosalpinx consists of muscular bundles independent of one another that follow multiple spatial arrangements and form a complex network. Such a type of structure seems to be capable of stirring rather than pushing the embryo and gametes.

Microplicae-like structures of the fallopian tube in postmenopausal women as shown by electron microscopy.

Female reproductive aging is associated with several morphological changes of the genital tract with a subsequent decline in fertility; however, ultrastructural changes occurring after menopause have still not been well illustrated. Our aim was to characterize the three-dimensional microanatomy of the luminal surface of the human fallopian tube in perimenopause and postmenopause. Twenty bioptic samples of fallopian tubes were obtained after surgery under the informed consent of the patients. Samples were processed for transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FE-SEM). As age increases the surface epithelium of the fallopian tube appeared somewhat flattened. Correlated TEM/FE-SEM observations showed gradual shortening of microvilli and deciliation. The most interesting finding was the gradual formation of microplicae-like structures on the surface epithelium, particularly from late perimenopause to postmenopause. Microplicae-like structures, associated with other regressive changes, represent an important adaptation of the epithelium of the fallopian tube; these are likely induced by the physiological process of aging, thus better withstanding hormonal changes associated with the advent of the menopause.

Microscopical survey of the development and differentiation of the epithelium of the uterine tube and uterus in the human fetus.

The development and differentiation of the coelomic epithelium lining the paramesonephric ducts in human fetus, that gives rise to the female genital organs, have been ultrastructurally examined. The epithelium appeared pseudostratified, consisting of basal, microvillous and ciliated cells. In younger fetuses (12th gestational week) ciliogenic elements could be detected mainly on the developing tubal fimbriae, but most of the cells showed microvilli and often single cilia. In the subsequent phases of development, morphodynamics of cell renewal were documented by aspects of apoptosis. Fully ciliated cells were numerous on the fimbriae and at the utero-tubal junction, but not in the uterus; however, these were less abundant than those showing microvillous. In older fetuses (31st gestational week) microapocrine secretion by microvillous cells, in the form of droplets contacting cilia, could be observed. In the same fetuses the ectocervix was covered by a mature squamous epithelium, made up of polygonal flat desquamating cells, showing labyrinthine surface microplicae. Our observations demonstrated that ciliation in the human female genital organs, like that of other systems, is neither simultaneous nor uniform, and ciliated cells are gathered preferentially in strategic sites, to mediate germ cell migration and blastocyst implantation in adult life. These ultrastructural data seem to indicate that the female genital tract epithelium, at least in its general features, is sketched since fetal life, and cell morphodynamics, including microvillous and ciliated cell differentiation, as well as the secretory activity, are the morphological expression of the complex molecular mechanisms, involved in developmental biology and reproductive physiology.

Cumulus oophorus extracellular matrix in the human oocyte: a role for adhesive proteins.

A viscous elastic matrix secreted by the cumulus oophorus cells represent the "extracellular matrix" surrounding the human mature oocyte obtained from assisted reproductive technology (ART). The cumulus matrix is involved in several reproductive processes, including the pick-up of the oocyte-cumulus complex by the oviduct, the final maturation of the ovum and sperm-egg interaction. As showed by some Authors, the cumulus matrix is rich in hyaluronan, as well as in other proteins including inter-alpha-trypsin inhibitor, a dermatan sulfate proteoglycan, and a pentraxin-3. Proteins and hyaluronan are linked together to form a meshwork comprised of granules and filaments. We found in human cumulus oocyte complexes the presence of specialized cells still capable of producing fibronectin and tenascin-c in the post-ovulatory period. Moreover, fibronectin and tenascin-c are present within the hyaluronan matrix at fertilization during the tubal sojourn of the ovum and the embryo. Since pentraxin3 is important in matrix stabilization and gamete interactions, a possible role for fibronectin and tenascin-c may be postulated in the final maturation of the ovum, in the tubal pick-up and in the complex dialogue with the tubal epithelium.

Pored domes in adrenocortical capillaries. An ultrastructural study in mammals.

The adrenocortical gland is one of the most vascularized organs of the mammalian body. It undergoes continuous morphological changes dynamically dependent upon special permeability conditions related to various physiological and physiopathological events. The adrenal cortex of different adult mammals (3 pigs, 2 mice, 3 sheep) was studied by means of scanning (SEM) and transmission (TEM) electron microscopy. As seen by SEM it is formed of polyhedral cells which delimit a characteristic continuous labyrinth system of intercellular lacunae occupied by sinusoid-like capillaries. The capillary wall is fenestrated and is lined by flattened endothelial cells with their nuclear part bulging into the capillary lumen. The fenestrae are round or oval pores measuring 50-100 nm in diameter. They are usually clustered to form sieve plates and characteristically present a thin membranous diaphragm. Irregular microelevations and dome-like projections are often seen. These structures are made of thin cytoplasmic plates interrupted by numerous small pores which show a sieve plate profile. The pored-domes on the nuclear portion seem to be identical in structure to those found in the thinner endothelial part; some of them appear to detach from the endothelial cell. The pored-domes are structurally comparable to those reported both in the renal glomerular endothelium and in liver sinusoids. These endothelial structures may be an expression of the high rate of filtration of these tissues and may be also related to the final step of the replacement of the sieve plates during endothelial regeneration.

Pietro Motta's latest studies on the microanatomy of menopause: revised concepts on the beauty of aging.

Menopause signs a hallmark in women's life. When compared to traditional two-dimensional techniques, scanning electron microscopy (SEM) allows to discover the impressive microcosm of the human body and offers original views of the real three-dimensional ultrastructure of reproduction. On the basis of Prof. Motta's last and original book, herein we show a selection of microscopic images that characterize the 3D changes taking place on the surface epithelia of the aging woman's reproductive tract. Biopsies of ovaries, tubes, uteruses, cervices and vaginas were obtained from women (45-72 years old) during surgical or endoscopical procedures and after the informed consent of the patients. Samples were processed for SEM as reported elsewhere. Reproductive aging is associated to epithelial flatness, higher stromal density, absence of ovarian follicles, thickening of vascular walls and lack of glandular secretion. The uterus and the tube show a morphodynamic sequence of gradual microvilli shortening, patchy to complete deciliation and formation of microplicae like structures. The formation of microplicae like structures is interpreted as an adaptive mechanical response of the genital epithelia to the new microenvironment. We can propose that these structures may represent the initial stage of a physiologic metaplasia. In conclusion, imaging of menopause through the use of SEM allows a better understanding of the morphological and physiopathological bases of female aging and represents a perfect blend of art and aesthetics: a further confirmation of the endless beauty of our inner microscopic anatomy.

A scanning electron-microscopic study of "supramarginal cells" in the pituitary cleft of the rat.

Unusual cells lying above the marginal cellular layer of the rat pituitary cleft were studied by SEM and TEM. These cells - from their location termed supramarginal cells - have a characteristically irregular cell body from which arise a number of long and thin branched processes ending among the microvilli and cilia of the marginal cells delimiting the anterior and posterior walls of the cleft. Some supramarginal cells are star-shaped elements with thin extensions, others have a triangular or spindle-shaped body from which emerge long ameboid processes with fibril-like projections. Miniblebs, miniruffles, occasional veils and short microvilli extend over the surface of these elements. Supramarginal cells are very similar to the "Kolmer epiplexus cells" originally found on the choroid plexus or other areas of the third ventricular wall where they are known as "supraependymal cells". Present evidence suggests that supramarginal cells of pituitary cleft might have phagocytic properties and an hematogenous origin as monocytes and, as such, closely resemble Kolmer epiplexus cells of brain ventricles. Others might arise from "folliculo-stellate cells" or closely related marginal cells once they become free into the pituitary cleft. Supramarginal cells are recognized as motile phagocytes acting as scavengers and possibly regulating the extracellular environment of the cleft and associated adenohypophysial tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Supramarginal cells in the rat pituitary cleft revealed by scanning electron microscopy.

An unusual cell type consisting of free elements widely scattered over the marginal epithelium of the rat pituitary cleft is revealed by SEM. Most of these supramarginal cells characteristically have irregularly shaped cell bodies from which thin branched processes extend. Supramarginal cells bear resemblances to Kolmer (epiplexus) cells and to supraependymal cells of the brain ventricles. Their ultrastructural features make it probable that supramarginal cells are phagocytes, and can be regarded as scavengers of the cleft. Considering the close topographical association between the hypophysial cleft and the floor or the 3rd ventricle, supramarginal cells may be members of the motile macrophagic Kolmer cells populating the ventricular surfaces of the brain.

Microperoxisomes in steroidogenic cells of the rat ovary: interstitial, thecal and luteal cells.

Microperoxisomes are present in luteal, interstitial and thecal cells. They are in close relation with smooth endoplasmic reticulum and lipids. Their probable role in steroid biosynthesis is discussed.

The structure of the human yolk sac: a scanning and transmission electron microscopic analysis.

Human yolk sacs were studied by light, transmission and scanning electron microscopy. Twelve human embryos at Carnegie stages ranging from 13 to 20 (28-49 days of gestation) were used for this research. The series of events which occur in the yolk sac wall during its period of maximum functional activity were recorded. The endodermal epithelium consisted of a single layer of columnar cells which, through cellular proliferation, formed endodermal cords which became cavitated, thereby forming endodermal vesicles. At the peak of yolk sac activity, intercellular spaces became very large and isolated individual endodermal cells. The epithelial cells were characterized by numerous microvilli on their free surface, high pinocytotic activity and by the formation of dense cisternae. Abundant intracellular vesicles fused together to empty their contents into the endodermal vesicles. The luminal surfaces of both intracellular and endodermal vesicles presented microvilli. The endodermal cells were characterized by an abundant granular endoplasmic reticulum, a well-developed Golgi apparatus, numerous mitochondria and glycogen particles. Endodermal vesicles were normally seen opening into the vitelline cavity through an endodermal orifice. The surface of the outer mesothelium was covered by numerous lengthy microvilli which were denser here than in the endodermal layer. A mucus-like material, present on the surface of the mesothelium, showed relatively few alterations during the study period. The mesothelial cells were less rich in organelles and far less active than the endodermal cells. The microanatomy of the endoderm supports the contention that its cells serve as absorptive structures as well as sites of protein synthesis during early embryonic development. Therefore, the endodermal vesicles could function as a pump regulating the fluid volume into the vitelline cavity, thereby avoiding the collapse of the organ due to the absorptive activity of the endodermal cells. Furthermore, mesothelial microvilli together with their mucous material harbor a layer of serous exudate and thus create a lubricated cushion designed to protect the thin mesothelium from frictional damage.

Oocyte follicle cells association during development of human ovarian follicle. A study by high resolution scanning and transmission electron microscopy.

Morphodynamics of oocyte follicle cells association during the development of human ovarian follicles were studied by transmission electron microscopy and high resolution scanning electron microscopy including the ODO method. For this study primordial, primary, growing preantral and antral follicles were systematically analysed in a total of 20 adult and fetal (3-8 months and at term) ovaries. In early stages of follicle development (primordial and primary stages) the flattened and/or polyhedral cells, closely associated with the growing oocyte, project an increasing number of microvillous processes. These are in apposition with the oolemma, and form bulbous terminals presenting attachment zones such as zonula adherens, desmosomes and communicating junctions (gap junctions). "Focal contacts" between oolemma, and lateral microvillous extensions of follicle cells were also present. Unusual forms of contact between follicle cell microvilli and oocytes in the early stages of growing primordial and primary follicles were also observed. These consist of long, thin extensions penetrating into the oocyte through deep invaginations of the oolemma. The aid of high resolution SEM of specimens subjected to the ODO method clearly reveals their 3-D arrangement within the ooplasm. They appear as long tortuous microvilli coming very close to the nucleus, and in their course are closely associated with a variety of organelles such as Golgi vesicles, endoplasmic reticulum membranes and nascent forms of smooth endoplasmic reticulum. Using integrated observations by TEM and SEM, there may be as many as 3-5 "intraooplasmic processes" even in only one plane of fracture of an oocyte. Therefore, if the total volume of the oocyte and associated cells is considered, their amounts appear to be higher than previously reported. Thus, they have to be considered as normal devices of deep contact between the ooplasm and associated follicle cell extensions. The presence of such structures within the ooplasm in early developing follicles well coincides with the great increase in volume of the oocyte. Although it is commonly believed that the activation of the growing oocyte may depend on the numerous contacts between the oolemma and follicle cells (mostly via gap junctions), the finding of these additional intraoocytic extensions suggests that they may in someway contribute to the initiation of growth in the human. In fact, these microvilli penetrate deep into the ooplasm, much like a sword in its sheath.(ABSTRACT TRUNCATED AT 400 WORDS)

The fetal development of the human uterine cervix from the 12th to the 31st postmenstrual week as revealed by scanning electron microscopy. Anatomical and clinical correlations.

To clarify the differentiation of the human uterine cervix, fetuses of the 12th, 15th, 18th, 20th, 21st, 22nd, and 31st postmenstrual week were studied by Scanning Electron Microscopy. At the 12th week the endocervical epithelium consisted of microvillous cells, often showing single cilia and anlages of tubular glands. At the 15th week the cervical canal was entirely formed and its surface cells appeared columnar. At the 18th week these cells were replaced by flat or slightly raised cells, provided with thin microplicae. At the 20th week the endocervical epithelium appeared pseudostratified with higher, apically-convex and shorter basal cells; glands developed in form of tubular invaginations of the luminal epithelium. At the 21st week in the lower part of the endocervix polymorphic, globose cells with short and stubby microvilli and others elongated, having short microplicae, were observed. These latter likely corresponded to the so-called columnar cells undergoing squamous metaplasia. Among microvillous and/or metaplastic cells, a number of apoptotic cells, as globose elements with a ruffled and invaginated surface, were also noted. At the 22nd week evident plicae palmatae were found, covered by microvillous secreting cells. These showed smooth bulged apices releasing droplets by a "micro-apocrine" mechanism. These features increased at the 31st week, when many droplets were noted also around the mouth of the cervical glands. Only at this phase of development fully ciliated cells were found often contacting secretory material. Mature squamous exfoliating cells with complex microplicae covered an hypertrophied portio vaginalis. The squamous cells extended toward a squamo-columnar junction in form of flat, tongue-like projections. Their tips consisted of immature squamous metaplastic cells, which were endocervical columnar progressively becoming elongated elements, exhibiting short microvilli. The above features are rather similar to those occurring during the adult reproductive age. Therefore, it might be hypothesized that, during pregnancy, a common gestational hormonal background may induce somewhat similar morpho-dynamic processes in the cells and tissues of the fetal reproductive tract mimicking what occurs in the adult female.

[Dynamic interaction between spermatozoa and the mucosa of the female genital tract in the mouse: study using scanning and transmission electron microscopy]. / Interaction dynamique entre les spermatozoïdes et la muqueuse du tractus génital féminin de la souris, étude au microscope électronique à balayage et à transmission.

Submicroscopic alterations occurring in mouse spermatozoa during their stay in the female reproductive tract as revealed by scanning and transmission electron microscopy using ruthenium red as marker for glycosaminoglycans are described in the present investigation. The results show that the surface of the plasma membrane covering the acrosomal region of the spermatozoa found in the uterus at different intervals of time after copulation (between 10 minutes up to 20 hours), was provided with an increasing number of granules and small vesicles. Some of the surface structures appear gradually leading to perforation of discrete areas of plasma membranes in regions corresponding to the acrosomal region covering the head of spermatozoa. Also the use of ruthenium red shows a significant decrease of glycosaminoglycans and their sialic acid moieties that specifically precede further vesiculation and fenestration (perforation) of the plasma membrane covering the same acrosomal regions.