http://repositorio.unne.edu.ar/handle/123456789/82 2026-04-10T15:41:03Z http://repositorio.unne.edu.ar/handle/123456789/60108 Gametogenesis in Rhinella bergi (Anura : Bufonidae) : morphological and morphometric analysis Cheij, Esteban Omar; Olea, Gabriela Beatriz; Rodríguez, Florencia Evelyn; Céspedez, Jorge Abel; Flores Quintana, Carolina Isabel This study aims to characterize the gonads, folliculogenesis, and spermatogenesis processes of male and female Rhinella bergi through anatomical, histological and morphometric analysis. We worked with specimens previously collected in the spring and summerseasons(2014–2015), in which the gonads were studied based on morphological, histological and morphometric analysis. The reproductive system was analyzed using a stereoscopic microscope and a scanning electron microscope (SEM). Histological preparations were made following the conventional protocol of dehydration, inclusion in paraffin and stained with haematoxylineosin, Mallory trichrome and PAS histochemical reactions. The anatomical and morphometric characteristics and the gametogenesis in R. bergi agree with what was proposed for other analyzed species of the Bufonidae family. Females with ovaries with oocytes in different stages of maturity and postovulatory females were found. The males presented continuous spermatogenesis. The results of this work serve as a basis for the characterization of the reproductive cycle in R. bergi and, at the same time, provide background information on the analysis of gametogenic activity. Future investigations will be focused on evaluating the reproductive cycle in this species, both in ovaries and testes as well as Bidder's organ, to compare and correlate with the results obtained in this study. 2023-01-01T00:00:00Z http://repositorio.unne.edu.ar/handle/123456789/59447 Systemic pathological alterations caused by Philodryas patagoniensis colubrid snake venom in rats Peichoto, María Elisa; Teibler, Gladys Pamela; Ruiz, Raquel Mónica; Leiva, Laura Cristina Ana; Acosta, Ofelia Cristina Very little is known about the systemic effects caused by Philodryas patagoniensis colubrid snake venom. In this work, this venom was tested for its ability to induce histopathological changes in rats after its intramuscular, subcutaneous, or intravenous administration, by light microscopic examination of some organs (cerebellum, cerebrum, lung, liver, kidney, and heart). Four rats were used for each dose of 0.23, 0.45, and 0.90 mg of venom in 0.3 ml of phosphate-buffered saline solution (pH 7.4). Aliquots of blood were withdrawn at different time intervals for enzymatic determination of alanine aminotransferase, aspartate aminotransferase, and creatine kinase levels. After 2 h the animals were killed by an overdose of anesthetic, and samples of kidney, heart, liver, lung, cerebrum, and cerebellum were taken for microscopic examination (hematoxylin and eosin stain). Histologically, no abnormality was observed in heart tissue in any of the administration routes of the venom used. However, histological observations showed multifocal hemorrhage in cerebellum, cerebrum, and lung sections; severe peritubular capillary congestion in kidney sections; and hydropic degeneration in liver sections when venom was administered intravenously. The subcutaneous route showed similar results to the previous one, with the exception of cerebellar hemorrhage. Intramuscularly, neither cerebral nor cerebellar hemorrhage was observed. Plasma alanine aminotransferase and aspartate aminotransferase increased levels were demonstrated, mainly when venom was administered intravenously or subcutaneously. Our results suggest that P. patagoniensis venom induces moderate histopathological changes in vital organs of rats. These changes are initiated at early stages of the envenomation and may be associated with a behavioral or functional abnormality of those organs during envenoming. 2006-10-01T00:00:00Z http://repositorio.unne.edu.ar/handle/123456789/59448 Neutralisation of the pharmacological activities of Bothrops alternatus venom by anti-PLA2 IgGs García Denegri, María Emilia; Maruñak, Silvana Licia; Todaro, Juan Santiago; Ponce-Soto, Luis Alberto; Acosta, Ofelia Cristina; Leiva, Laura Cristina Ana Basic phospholipases A2 (PLA2) are toxic and induce a wide spectrum of pharmacological effects, although the acidic enzyme types are not lethal or cause low lethality. Therefore, it is challenging to elucidate the mechanism of action of acidic phospholipases. This study used the acidic non-toxic Ba SpII RP4 PLA2 from Bothrops alternatus as an antigen to develop anti-PLA2 IgG antibodies in rabbits and used in vivo assays to examine the changes in crude venom when pre-incubated with these antibodies. Using Ouchterlony and western blot analyses on B. alternatus venom, we examined the specificity and sensitivity of phospholipase A2 recognition by the specific antibodies (anti-PLA2 IgG). Neutralisation assays using a non-toxic PLA2 antigen revealed unexpected results. The (indirect) haemolytic activity of whole venom was completely inhibited, and all catalytically active phospholipases A2 were blocked. Myotoxicity and lethality were reduced when the crude venom was pre-incubated with anti-PLA2 immunoglobulins. CK levels in the skeletal muscle were significantly reduced at 6 h, and the muscular damage was more significant at this time-point compared to 3 and 12 h. When four times the LD50 was used (224 μg), half the animals treated with the venom–anti PLA2 IgG mixture survived after 48 h. All assays performed with the specific antibodies revealed that Ba SpII RP4 PLA2 had a synergistic effect on whole-venom toxicity. IgG antibodies against the venom of the Argentinean species B. alternatus represent a valuable tool for elucidation of the roles of acidic PLA2 that appear to have purely digestive roles and for further studies on immunotherapy and snake envenoming in affected areas in Argentina and Brazil. Preguntar a ChatGPT 2014-08-01T00:00:00Z http://repositorio.unne.edu.ar/handle/123456789/59446 Muscle and skin necrotizing and edema-forming activities of Duvernoy’s gland secretion of the xenodontine colubrid snake Philodryas patagoniensis from the North-east of Argentina Peichoto, Peichoto, María Elisa; Acosta, Ofelia Cristina; Leiva, Laura Cristina Ana; Teibler, Gladys Pamela; Maruñak, Silvana Licia; Ruiz, Raquel Mónica Philodryas patagoniensis is a colubrid snake spread throughout South America, but very little is known about the composition and biological activities of its Duvernoy’s gland secretion. In order to characterize it, we studied edematogenic, dermonecrotic, and myonecrotic activities. For edematogenic activity, solutions containing different amounts of secretion were injected subcutaneously in the right foot pad of mice; both feet were subsequently cut off and weighed individually. For myonecrotic activity, mice were injected intramuscularly with solutions containing 40 μg of secretion, and at various time intervals mice were bled to determine serum creatine kinase activity and gastrocnemius muscles were removed for microscopic examination (Hematoxylin–Eosin stain). For dermonecrotic activity, solutions containing different amounts of secretion were injected into the shaved dorsal skin of mice; the necrotic lesion was measured on the inner surface of the skin and trimmed for microscopic examination (Hematoxylin–Eosin stain). Phospholipase A2 activity was evaluated using a kinetic method. Results showed that P. patagoniensis Duvernoy’s gland secretion exhibits high edematogenic activity and moderate myonecrotic and dermonecrotic activities, while lacking phospholipase A2 effect. Regarding edema, a 30% increase in the weight was produced by injecting 0.26 mg of Duvernoy’s gland secretion. Microscopically, myonecrosis reached its highest intensity 12 h after injection, which was also demonstrated by serum creatine kinase levels. Dermonecrosis was proportional to the amount of secretion injected, with a minimum necrotizing dose of 15.7 mg. Myonecrotic, edematogenic, and dermonecrotic activities were inhibited when the secretion was pre-incubated with 1 mM Na₂EDTA. This suggests that the enzymes responsible for those activities are mostly metalloproteinases. All the studies carried out up to now demonstrate the potential toxicity of P. patagoniensis Duvernoy’s gland secretion (which inhabits the northeast region of Argentina) and that the local lesions caused by this colubrid snake are very similar to those found in bothropic accidents. This latter suggests a more careful evaluation of the victims when considering the medical treatment to be adopted. 2004-11-01T00:00:00Z