The aim of this study has been to observe, by electron microscopy, the morphological changes affecting mitochondria and associated organelles in the human female germ cell during oogenesis, maturation and fertilization. In the primordial germ cell (PGC), rounded mitochondria with a pale matrix and small vesicular cristae are disposed near the nucleus and significantly increase in number during PGC migration and settlement in the gonadal ridge, where they differentiate into oogonia. In these early stages of mammalian oogenesis, aggregates of mitochondria are typically clustered around or in close relationship with the nuage. In oocytes at early prophase stage, mitochondria proliferate while aligned along the outer surface of the nuclear membrane, contain a more dense matrix than before, and have lamellar cristae. Oocytes of primordial and primary follicles mostly contain round or irregular mitochondria whose matrix has become very light. These mitochondria show typical parallel, arched cristae, and are clustered near the nucleus with other organelles forming the Balbiani's vitelline body. When follicles grow, the mitochondria of the oocytes become even more numerous and are dispersed in the ooplasm. Both paranuclear accumulation and subsequent dispersion of mitochondria in the cytoplasm are likely to be regulated by microtubules. By ovulation, mitochondria are the most prominent organelles in the ooplasm. They form voluminous aggregates with smooth endoplasmic reticulum (SER) tubules and vesicles. These mitochondrial-SER aggregates (M-SER) and the mitochondrial-vesicle complexes (MV) could be involved in the production of a reservoir of substances or membranes anticipating subsequent fertilization and early embryogenesis. Just after fertilization, the mitochondria of the oocyte undergo a further substantial change in size, shape, and microtopography. In the pronuclear zygote, mitochondria concentrate around the pronuclei. During the first embryonic cleavage divisions, round or oval mitochondria with a dense matrix and few arched cristae are gradually replaced by elongated ones with a less dense matrix and numerous transverse cristae. A progressive reduction in size and number of M-SER aggregates and MV complexes also occurs. In summary, oocyte mitochondria show dynamic morphological changes as they increase in number and populate different cell domains within the oocyte. They form complex relationships with other cell organelles, according to the different energetic -metabolic needs of the cell during differentiation, maturation, and fertilization, and are ultimately inherited by the developing embryo, where they eventually assume a more typical somatic cell form.

The mammalian zona pellucida (ZP) is an extracellular matrix surrounding oocytes and early embryos, which is critical for normal fertilization and preimplantation development. It is made up of three/four glycoproteins arranged in a delicate filamentous matrix. Scanning electron microscopy (SEM) studies have shown that ZP has a porous, net-like structure and/or nearly smooth and compact aspect. In this study, the fine 3-D structure of the human and mouse ZP is reviewed with the aim to integrate ultrastructural and molecular data, considering that the mouse is still used as a good model for human fertilization. By conventional SEM observations, numerous evidences support that the spongy ZP appearance well correlates with mature oocytes. When observed through more sophisticated techniques at high resolution SEM, ZP showed a delicate meshwork of thin interconnected filaments, in a regular alternating pattern of wide and tight meshes. In mature oocytes, the wide meshes correspond to "pores" of the "spongy" ZP, whereas the tight meshes correspond to the compact parts of the ZP surrounding the pores. In conclusion, the traditional "spongy" or "compact" appearance of the ZP at conventional SEM appears to be only the consequence of a prevalence of different arrangements of microfilament networks, according to the maturation stage of the oocyte, and in agreement with the modern supramolecular model of the ZP at the basis of egg-sperm recognition. Despite great differences in molecular characterization of ZP glycoproteins between human and mouse ZP, there are no differences in the 3-D organization of glycoproteic microfilaments in these species.

The frequent occurrence of normal SVs in varicose limbs of all patients does not support the crucial role commonly credited to SVs in the pathogenesis of primary varicosities. Moreover, the SV trunks were normal in most varicose limbs from young patients. These findings suggest that varicose disease may progressively extend in an antegrade fashion, spreading from the STVs to the SVs. This hypothesis suggests that the saphenous trunks could be spared in the treatment of a relevant number of varicose legs. Prospective longitudinal studies with serial duplex evaluations of large series of extremities are necessary to confirm this hypothesis.

No abstract

Supernumerary ossicles (or Wormian bones) of the cranial vault are formations associated with insufficient rate of suture closure, and regarded as "epigenetic" and "hypostotic" traits. These bones rest along sutures and/or fill fontanelles of the neonatal skull. In this autoptic report of a 66-year-old Caucasian woman, a peculiar supernumerary bone is described, unusual size and shape, filling completely the bregmatic fontanelle. The skull was CT-scanned through coronal sections at 80 kV and 60 mA, with a slice thickness of 1.0 mm and a resolution of 0.35 mm/pixel. Segmentation and 3D rendering were computed using MIMICS 7.0 (digital endocast). The bone was pentagonal and remarkably large, more on the exocranial surface than on the endocranial one, involving both tables and diploe of the vault. This feature might represent a wedge to completion of the vault architecture. Considering the functional and structural matrix of cranial morphogenesis, this case displays the possibility of discrete diversification of the ossification centres, as well as the relative stability of the structural skull matrix in response to discrete changes.

The use of somatic cells for cocultures during in vitro fertilization (IVF) is currently finalized to obtain a higher number of healthy and viable embryos with a high potential of implantation. Among the different cell lines that can be used as feeder cells for cocultures, granulosa cells (GCs) are autologous cells, safe and easy to recover. The aim of the present study was to analyze the fine structure of human GCs used in a coculture system to evaluate, from a morphodynamic point of view, their role in supporting embryo development. GCs were collected during oocyte pick-up, 36 h after human chorionic gonadotropin administration, from patients undergoing IVF procedures, who had given their informed consent to be included in this protocol. After coculture, GCs were fixed and processed for light microscopy (LM) and transmission electron microscopy (TEM). By LM, GCs appeared as clusters of loosely packed cells, irregularly rounded or polyhedral in shape, varying in diameter from 18 to 25 microm. Mitotic cells, as well as regressing elements (with pyknotic nuclei or dense cytoplasm) and cell fragments were occasionally observed. By TEM, the plasma membrane was irregular due to the presence of cytoplasmic evaginations. Linear and annular gap junctions between neighboring GCs were found. GC nuclei, rounded and eccentrically located, contained finely dispersed chromatin, one (often two) prominent nucleoli and, infrequently, peripheral patches of heterochromatin. Numerous organelles populated the GC cytoplasm, among them, mitochondria were rod-shaped or elongated, usually provided with tubular-vesicular cristae but occasionally showing atypical, longitudinally oriented cristae. Membranes of smooth endoplasmic reticulum, Golgi stacks and vesicles, secretory-like granules, cisternae of rough endoplasmic reticulum (RER), free ribosomes and polysomes, lysosomal-like bodies, microfilaments, and lipid droplets were also seen in the GC cytoplasm. In most cells, RER was scarcely represented and numerous lipid droplets filled the perinuclear space. On the contrary, some GCs contained an abundant RER and rare lipid droplets scattered in the cytoplasm. In conclusion, our data demonstrated the presence, in a coculture system, of GCs provided with ultrastructural characteristics typical of healthy, metabolically active, mostly steroidogenic cells. Protein-synthetic cells have also been detected. These data, evaluated at the light of biochemical and clinical studies, sustain the capability of human GCs cocultures to positively affect early embryo development in vitro by the secretion of steroids and proteins, putative "embryotrophic" factors.

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.

There is emerging evidence that early uterine development in humans is an important determinant of conditions such as ontogenetic progesterone resistance, menstrual preconditioning, defective deep placentation and pre-eclampsia in young adolescents. A key observation is the relative infrequency of neonatal uterine bleeding and hormone withdrawal at birth. The origin of the uterus from the fusion of the two paramesonephric, or Müllerian, ducts was described almost 200 years ago. The uterus forms around the 10th week of foetal life. The uterine corpus and the cervix react differently to the circulating steroid hormones during pregnancy. Adult uterine proportions are not attained until after puberty. It is unclear if the endometrial microbiome and immune response—which are areas of growing interest in the adult—play a role in the early stages of uterine development. The aim is to review the phases of uterine development up until the onset of puberty in order to trace the origin of abnormal development and to assess current knowledge for features that may be linked to conditions encountered later in life. The narrative review incorporates literature searches of Medline, PubMed and Scopus using the broad terms individually and then in combination: uterus, development, anatomy, microscopy, embryology, foetus, (pre)-puberty, menarche, microbiome and immune cells. Identified articles were assessed manually for relevance, any linked articles and historical textbooks. We included some animal studies of molecular mechanisms. There are competing theories about the contributions of the Müllerian and Wolffian ducts to the developing uterus. Endometrium features are suggestive of an oestrogen effect at 16–20 weeks gestation. The discrepancy in the reported expression of oestrogen receptor is likely to be related to the higher sensitivity of more recent techniques. Primitive endometrial glands appear around 20 weeks. Features of progestogen action are expressed late in the third trimester. Interestingly, progesterone receptor expression is higher at mid-gestation than at birth when features of endometrial maturation are rare. Neonatal uterine bleeding occurs in around 5% of neonates. Myometrial differentiation progresses from the mesenchyme surrounding the endometrium at the level of the cervix. During infancy, the uterus and endometrium remain inactive. The beginning of uterine growth precedes the onset of puberty and continues for several years after menarche. Uterine anomalies may result from fusion defects or atresia of one or both Müllerian ducts. Organogenetic differentiation of Müllerian epithelium to form the endometrial and endocervical epithelium may be independent of circulating steroids. A number of genes have been identified that are involved in endometrial and myometrial differentiation although gene mutations have not been demonstrated to be common in cases of uterine malformation. The role, if any, of the microbiome in relation to uterine development remains speculative. Modern molecular techniques applied to rodent models have enhanced our understanding of uterine molecular mechanisms and their interactions. However, little is known about functional correlates or features with relevance to adult onset of uterine disease in humans. Prepubertal growth and development lends itself to non-invasive diagnostics such as ultrasound and MRI. Increased awareness of the occurrence of neonatal uterine bleeding and of the potential impact on adult onset disease may stimulate renewed research in this area.