Janaina Serra Azul Monteiro Evangelista

Renal and vascular effects of the natriuretic peptide isolated from Crotalus durissus cascavella venom

Crotalus durissus cascavella is a snake that is usually found in the scrublands of northeast Brazil. The components of its venom may have effects on the vascular and renal systems. Recently, a new bradykinin inhibitory peptide has been identified in the venom of the Crotalinae family. The aim of the present study was to investigate the renal and vascular effects of the natriuretic peptide isolated from the venom of Crotalus durissus cascavella (NP2_Casca). The chromatographic profile showed the fractionation of substances identified as convulxin, gyroxin, crotoxin and crotamine, as well as fractions V and VI. The electrophoretic profile of fraction V consisted of several bands ranging from approximately 6kDa to 13kDa, while fraction VI showed only two main electrophoretic bands with molecular weights of approximately 6 and 14kDa. Reverse-phase chromatography showed that NP2_Casca corresponds to about 18% of fraction VI and that this fraction is the main natriuretic peptide. NP2_Casca was compared to other natriuretic peptides from other sources of snake venom. All amino acid sequences that were compared showed a consensus region of XGCFGX, XLDRIX and XSGLGCX. The group treated with NP2_Casca showed an increase in perfusion pressure, renal vascular resistance, urinary flow and glomerular filtration rate. The percent of total and proximal tubular transport of sodium was reduced significantly after administration of the peptide. The mean arterial pressure showed a dose-dependent decrease after infusion of NP2_Casca, and an increase in nitrite production. In the aortic ring assay, NP2_Casca caused a relaxant effect in endothelium-intact thoracic aortic rings precontracted with phenylephrine in the presence and absence of isatin. NP2_Casca failed to relax the aortic rings precontracted with an isosmotic potassium Krebs-Henseleit solution. In conclusion, the natriuretic peptide isolated from Crotalus durissus cascavella venom produced renal and vascular effects. NP2_Casca reduced total and proximal sodium tubular transport, leading to an increase in sodium excretion, thereby demonstrating a diuretic action. A hypotensive effect was displayed in an arterial pressure assay, with an increase in nitrite production, suggesting a possible vasoactive action.

Renal and cardiovascular effects of Bothrops marajoensis venom and phospholipase A2

Bothrops marajoensis is found in the savannah of Marajó Island in the State of Pará and regions of Amapá State, Brazil. The aim of the work was to study the renal and cardiovascular effects of the B. marajoensis venom and phospholipase A(2) (PLA(2)). The venom was fractionated by Protein Pack 5PW. N-terminal amino acid sequencing of sPLA(2) showed amino acid identity with other lysine K49 sPLA(2)s of snake venom. B. marajoensis venom (30 microg/mL) decreased the perfusion pressure, renal vascular resistance, urinary flow, glomerular filtration rate and sodium tubular transport. PLA(2) did not change the renal parameters. The perfusion pressure of the mesenteric bed did not change after infusion of venom. In isolated heart, the venom decreased the force of contraction and increased PP but did not change coronary flow. In the arterial pressure, the venom and PLA(2) decreased mean arterial pressure and cardiac frequency. The presence of atrial flutter and late hyperpolarisation reversed, indicating QRS complex arrhythmia and dysfunction in atrial conduction. In conclusion, B. marajoensis venom and PLA(2) induce hypotension and bradycardia while simultaneously blocking electrical conduction in the heart. Moreover, the decrease in glomerular filtration rate, urinary flow and electrolyte transport demonstrates physiological changes to the renal system.

Antiophidic Solanidane Steroidal Alkaloids from Solanum campaniforme

Three new solanidane alkaloids bearing a 22,23-epoxy ring (1-3) and four known compounds were isolated from leaves of Solanum campaniforme. The structures were determined using spectroscopic techniques, including 1D and 2D NMR, and HRESIMS experiments. The antiophidic activity of the alkaloids was tested against Bothrops pauloensis venom. Compounds 1-3 completely inhibited myotoxicity without inhibiting phospholipase A2 activity of the venom, while hemorrhage and skin necrosis were significantly reduced in the presence of alkaloids 1 and 2.

Renal effects induced by the lectin from Vatairea macrocarpa seeds

Lectins are glycoproteins that interact reversibly and specifically with carbohydrates. The renal effects of the galactose‐binding lectin from the seeds of Vatairea macrocarpa were investigated. Isolated kidneys from Wistar rats (240–280 g) were perfused with Krebs‐Henseleit solution containing 6% bovine serum albumin. The V. macrocarpa lectin (10 μg mL−1) increased the perfusion pressure, renal vascular resistance, urinary flow and glomerular filtration rate. However, V. macrocarpa lectin did not change the percentage sodium, potassium or chloride tubular transport. Pretreatment with lectin‐galactose complex significantly blocked the increase in perfusion pressure, renal vascular resistance, urinary flow and glomerular filtration rate. The control group showed a small amount of a proteinaceous material in the urinary space, although no alteration in the renal tubules was detected. The administration of galactose alone did not modify the functional parameters of the kidney. Kidneys perfused with V. macrocarpa lectin showed moderate deposits of a proteinaceous material in the tubules and urinary space. Those pre‐treated with lectin‐galactose complex had only small amount of a proteinaceous material in the urinary space. No abnormalities were seen in renal tubules. The results suggest that lectin from V. macrocarpa seeds has important effects on the carbohydrate‐binding sites of the renal system, given the reversal of renal effects with the use of that specific inhibitor.

Isolation and pharmacological effects of leptoxin, a novel proteic toxin from Leptodactylus pentadactylus skin secretion.

The in vivo and in vitro pharmacological effects of leptoxin, one of the most lethal protein toxins known at present date (LD(50) 0.5+/-0.03 microg/kg i.v., mice) isolated from Leptodactylus pentadactylus skin secretion, were studied. In rats, leptoxin (1.0 microg/kg, i.v.) induced cardiorespiratory collapse with abundant tracheal secretion followed by sudden death. The cardiovascular shock, pulmonary edema and mortality were not prevented by pretreating the animals with effective doses of pharmacological blockers, i.e., atropine with or without bilateral vagotomy, phentolamine, propranolol, hexamethonium, captopril, dexamethasone, indomethacin, L-NAME, promethazine, Ginkgolide BN-52021 or tezosentan. Pulmonary macroscopic examination revealed increased tracheobronchial secretion, hemorrhagic areas and edema. Microscopic examination showed intense vascular congestion, alveolar and septal interstitial hemorrhage and alveolar edema, without infiltrated inflammatory cells. Leptoxin increased pulmonary index (0.67+/-0.09 vs. 1.55+/-0.24; p<0.05) and the Evans blue concentration in the bronchoalveolar fluid (1.24+/-0.17 vs. 4.17+/-1.47 microg/microL; p<0.01) and in the lung parenchyma (40.73+/-3.27 vs. 65.33+/-4.51 microg/microL; p<0.03). Leptoxin increased the pulmonary perfusion pressure from 13.7+/-5.3 to 54.0+/-6.3 mmHg. It also induced a vasoconstrictor effect in the perfused mesenteric vascular bed that could be explained by a hyperreactivity to phenylephrine. Thus, the results suggest that leptoxin-induced death occurs by acute pulmonary edema due to increased microvascular pulmonary pressure evoked by direct vasoconstriction. Despite its strong toxicity, the role of leptoxin in L. pentadactylus skin remains unknown.

Evaluation of KIM-1 as an early biomarker of snakebite-induced AKI in mice

ABSTRACT Acute kidney injury (AKI) is one of the most important complications of bothropic poisoning and its early identification remains challenging. The nephrotoxicity of Bothrops insularis venom (BinsV) was previously described by our research group. In this study, we continued to evaluate the effect of BinsV on kidney function in mice and LLC‐MK2 proximal tubule cells, evaluating KIM‐1 protein as an early AKI biomarker. Male Swiss mice were inoculated with BinsV intramuscularly and observed for 24 h in a metabolic cage model. Urine and blood were collected for biochemical analyses and the kidneys were examined for oxide‐reducing balance and submitted to histological analysis. LLC‐MK2 cells incubated with BinsV were assessed for cell viability and cell death mechanism by flow cytometry. Histological analysis of the kidneys indicated AKI and the oxide‐reducing analyses demonstrated a decreasing in reduced glutathione (GSH) levels and an increasing on Malondialdehyde (MDA) levels. BinsV was cytotoxic to LLC‐MK2 and the cytometry analyses suggested necrosis. Within 24 h after the envenomation, urinary creatinine did not increase, but the urinary levels of KIM‐1 increased. In conclusion, we found AKI evidence in the kidney tissue and the increase in the KIM‐1 levels suggest it can be used as an early AKI biomarker. HighlightsBothrops insularis venom (BinsV) is nephrotoxic.BinsV induces Acute Kidney Injury in mice.Discrepancies were observed between plasmatic creatinine and histological findings.Urinary KIM‐1 was increased in mice inoculated with BinsV after 24 h.Urinary KIM‐1 was suggested as specific and early AKI biomarker on envenomation.

Crotalus durissus venom: biological effects and relevant applications. A Review

Snakes have an important biological role in the ecological chain, as well as in scientific researches performed with the venoms produced by them, since the enzyme-protein fractions these substances possess have been studied as pharmacological tools for the discovery of new therapies. Snakes of the genus Crotalus have gained significant relevance in the scientific field, since the venom produced by these reptiles has been the target of researchers in a few decades, due to the composition and the effects that these substances can produce. In Brazil, a single species represents the genus, which is Crotalus durissus. This review demonstrates that even with the advancement in scientific research on the composition, role and application of the venom produced by the subspecies of Crotalus durissus snake, it is necessary to further study their fractions and their action potential, which also demonstrates the how rich are these active components in different fields of biomedicine.

Clinical and laboratory diagnostic approach of intratbuluar sertolioma in a cryptorchid dog

Sertolioma is a common type of primary unilateral or bilateral testicular cancer, generally without signs that indicate the possibility of metastasis. This paper describes the clinical and laboratory diagnostic approach of a cryptorchid dog with sertolioma. The object of study was a male Pinscher dog, which reported the presence of a nodule in the inguinal region by its owner. Upon the nodule palpation during the physical examination, it was found the presence of edema and increased volume with firm consistency, but without fibrous features. Complete blood count, serum biochemical tests, ECG and echocardiogram, and fine-needle aspiration cytology were requested. Among other findings, cytology showed changes suggesting sertolioma: Numerous round and polygonal cells of large cytoplasm,

Gastrotomy in dog for removal of foreign body in caudal esophagus. Case report

Foreign bodies are digestible or not objects that can cause esophageal obstruction. Once located, the clinician must decide whether to observe its passage or perform the removal, being immediate intervention the most recommended. With that, we aimed to report a case of foreign body in the caudal esophagus of a canine, female, 8 years, with history of regurgitation and hyporexia. Based on anamnesis and physical examination findings, radiographs were performed in the laterolateral and ventrodorsal incidences, which showed the presence of radiopaque image (bone), confirming the presence of esophageal foreign body. In addition, ultrasound was requested and tests of serum biochemistry, all with no changes. As conduct, gastrostomy was performed to remove the bone and desobstruction.

Feline hypertrophic cardiomyopathy relevant aspects

Hypertrophic cardiomyopathy is a clinically heterogeneous disorder characterized by mild to severe thickening of left ventricular chamber associated with diastolic dysfunction. The main clinical signs are typically respiratory abnormalities secondary to pulmonary edema and/or pleural effusion; mild to severe acute heart failure; and paraparesis/paraplegia caused by arterial thromboembolism. The diagnosis should be based on a positive family history and the causes that cause secondary hypertrophy should be discarded. Echocardiography is currently the gold standard for the diagnosis of this pathology. It is the most common heart disease in adult cats; therefore, it is necessary knowledge of the condition in order to perform an effective clinical management, improving prognosis and quality of life of the animal.