Publications by authors named "Lucas Castanhola Dias"
Article Synopsis
- The study focused on identifying sexual dimorphism in stillborn hawksbill sea turtles by examining the morphological differences in their gonads using various microscopy techniques.
- Female gonads were characterized by a spindle shape and a grainy texture, while male gonads were ovoid and had a smooth surface, indicating distinct structural differences.
- Microscopic and ultrastructural analyses revealed unique cellular arrangements in females with oocytes and blood vessels, compared to males, which had testicular cords and distinct cell types, confirming these evaluation methods are reliable for sex determination in these turtles.
Progesterone receptors in extratesticular ducts of the Amazonian stingray Potamotrygon wallacei: A potential role in sperm maturation and aggregate formation.
Gen Comp Endocrinol
December 2023
Article Synopsis
- The study investigates the role of progesterone (P) in sperm maturation and aggregation in male cururu stingrays, focusing on the morphology of extratesticular ducts and the presence of progesterone receptors (PR).
- It was found that morphologically, all ducts had a specific type of epithelium, and active males had PR present in secretory cells, while regressing males lacked PR in crucial areas for sperm nurturing.
- The findings suggest that P is important for sperm metabolism, storage, and the formation of sperm aggregates, indicating its regulatory role during different reproductive phases in this species.
Pronephros and mesonephros characterization during the embryonic development of the giant South American river turtle, Podocnemis expansa (Podocnemididae: Testudines).
Anat Rec (Hoboken)
August 2023
This study aimed to describe pronephros and mesonephros morphology during the embryonic development of Podocnemis expansa. Eggs were collected on an artificial beach at Balbina, Amazonas, Brazil, during the entire incubation period (mean of 59 days). The kidney-gonad complex was processed using light microscopy and the mesonephros using transmission electron microscopy.
View Article and Find Full Text PDFArticle Synopsis
- * The study investigated the presence and characteristics of steroidogenic cells in the mesonephros of turtle embryos, specifically examining their structure through various microscopy techniques.
- * Results revealed that these cells display features typical of steroid-producing cells, indicating that the mesonephros may have a key role in the gonadal differentiation of the turtle species P. expansa.
Cardiogenesis is similar in all vertebrates, but differences in the valvuloseptal morphogenesis among non-crocodilian reptiles, birds, and mammals are noted. The origin of mesenchymal structures such as valves that regulate the passage of blood and the formation of partial septa that prevent the complete mixing of oxygen-rich and low-oxygen blood present in adult chelonians are essential in the evolutionary understanding of complete septation, endothermy and malformations, even in mammals. In this context, this study analyzed the heart morphogenesis of Podocnemis unifilis (Testudines: Podocnemididae) from the 4th to the 60th day of incubation.
View Article and Find Full Text PDFThe egg is one of the fundamental parts of the life cycle of Neoechinorhynchus buttnerae, and this stage involves the acanthor larva. It is also the infection phase for the intermediate host. Under normal conditions, the larva inside the egg can survive for months in the environment; however, information regarding this phase of life of the parasite is scarce.
View Article and Find Full Text PDFPathological findings and morphologic correlation of the lungs of autopsied patients with SARS-CoV-2 infection in the Brazilian Amazon using transmission electron microscopy.
Rev Soc Bras Med Trop
April 2021
Introduction: Electron microscopy (EM) is a rapid and effective tool that can be used to create images of a whole spectrum of virus-host interactions and, as such, has long been used in the discovery and description of viral mechanisms.
Methods: Electron microscopy was used to evaluate the pulmonary pathologies of postmortem lung sections from three patients who died from infection with SARS-associated coronavirus 2 (SARS-CoV-2), a new member of the Coronaviridae family.
Results: Diffuse alveolar damage (DAD) was predominant in all three patients.
Neutralization of the edema-forming and myotoxic activities of the venom of Potamotrygon motoro Müller and Henle, 1841 (Chondrichthyes - Potamotrygoninae) by antivenoms and circulating immunoglobulins.
Toxicon
October 2020
Article Synopsis
- * The study investigated whether antibodies against Potamotrygon motoro venom could neutralize its harmful effects using protocols on mice, including seroneutralization and vaccination.
- * Results showed that neither protocol fully neutralized the venom’s effects, but vaccination with stinger extract did prevent systemic muscle damage, and different immune responses were triggered depending on the method used.