Stereological study of organelle distribution in human mature oocytes.

The ultrastructure of human oocytes has been described only qualitatively. To offer a precise organelle spatial distribution and organelle volume during the main maturation stages, we previously conducted stereological studies on prophase-I (GV) and metaphase-I (MI) oocytes, and here we present results on metaphase-II (MII) oocytes. Five donor oocytes from different donors were processed for transmission electron microscopy, and quantification of organelle distribution was performed using point-counting stereology.

Updating an Overview of Teratology.

In this chapter, the authors aim to update an overview of the principles of teratology, beginning with the definition of teratology, the critical point at which this process occurs, and some of the most common etiological agents that improve our understanding of teratology.Modern teratology has greatly improved in recent years with advances in new methods in molecular biology, toxicology, animal laboratory science, and genetics, increasing our knowledge of ambient influences. Nevertheless, there is a lot to do to reduce the influence of hazardous intervening agents, whether they target our genetics or not, that can negatively affect pregnancy and induce congenital development disorders, including morphological, biochemical, or behavioral defects.

A spontaneous ovarian teratoma in an FVB/n female mouse: Case report and literature review.

Background: Teratomas are rare types of germ cell neoplasms composed of various differentiated or undifferentiated tissues.

Case Description: A 25-week-old female control FVB /n mouse in a 4-week toxicity study presented abdominal distension and poor body condition. It was euthanized, and the necropsy examination revealed a large mass connected to the tip of the right uterine horn, occupying the entire abdominal cavity.

Spatial Distribution of SARS-CoV-2 Receptors and Proteases in Testicular Cells.

Coronavirus disease (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). SARS-CoV-2 RNA has been found in the human testis on occasion, but subgenomic SARS-CoV-2 and infectious SARS-CoV-2 virions have not been found. There is no direct evidence of SARS-CoV-2 infection of testicular cells.

The effect of benzyl isothiocyanate on Candida albicans growth, cell size, morphogenesis, and ultrastructure.

Candida albicans is a commensal yeast that may become pathogenic and even lethal to the host. Over the last few decades, antifungal resistance has increased, promoting screening of the antifungal potential of old and new substances. This study investigates the antifungal potential of isothiocyanates (ITCs) against C.

An Overview of Teratology.

In this chapter, we provide an overview of the basic principles of teratology, beginning with its definition, the critical point for teratogenesis to occur and the most evident etiological agents to improve the understanding of this science.Teratology is a recent science that began in the early twentieth century, and has greatly improved over the recent years with the advancements in molecular biology, toxicology, animal laboratory science, and genetics, as well as the improvement on the knowledge of the environmental influences.Nevertheless, more work is required to reduce the influence of hazardous products that could be deleterious during pregnancy, thus reducing teratogenic defects in the newborn.

Electron Microscopy Findings in N-Methyl-N-Nitrosourea-Induced Mammary Tumors.

Although the rat model of mammary tumors chemically induced by N-methyl-N-nitrosourea (MNU) has been frequently used by several research teams, there is a lack of ultrastructural studies in this field. The main aim of this work was to perform an ultrastructural characterization of MNU-induced mammary tumors in female rats. Some alterations previously reported in human mammary tumors, such as nucleus size and shape, accumulation of heterochromatin in the perinuclear region, and interdigitating cytoplasmic processes between cancer cells were also observed in MNU-induced mammary tumors.

Ultrastructural and cytochemical characterization of follicular cell types in bovine (Bos taurus) cumulus-oocyte complexes aspirated from small and medium antral follicles during the estrus cycle.

Stereological quantitative methods have revealed the presence of three distinct follicular cell populations (C1-C3) in bovine cumulus-oocyte complexes. Type C3 cells became largely predominant from metestrous to proestrous, with a simultaneously large decrease in the other two cell types. To further characterize these cumulus cell types, cumulus-oocyte complexes from small (1-4mm) and medium (4-8mm) antral follicles (category 1: with a compact multilayered cumulus and a homogeneous ooplasm) were aspirated from ovaries of Holstein-Friesian cows and processed for electron microscopy, ultrastructural cytochemical detection of glycogen and glycoproteins, and immunogold localization of chondroitin sulfate.