Na+/K+-ATPase: More than an Electrogenic Pump.

The sodium pump, or Na+/K+-ATPase (NKA), is an essential enzyme found in the plasma membrane of all animal cells. Its primary role is to transport sodium (Na+) and potassium (K+) ions across the cell membrane, using energy from ATP hydrolysis. This transport creates and maintains an electrochemical gradient, which is crucial for various cellular processes, including cell volume regulation, electrical excitability, and secondary active transport. Although the role of NKA as a pump was discovered and demonstrated several decades ago, it remains the subject of intense research. Current studies aim to delve deeper into several aspects of this molecular entity, such as describing its structure and mode of operation in atomic detail, understanding its molecular and functional diversity, and examining the consequences of its malfunction due to structural alterations. Additionally, researchers are investigating the effects of various substances that amplify or decrease its pumping activity. Beyond its role as a pump, growing evidence indicates that in various cell types, NKA also functions as a receptor for cardiac glycosides like ouabain. This receptor activity triggers the activation of various signaling pathways, producing significant morphological and physiological effects. In this report, we present the results of a comprehensive review of the most outstanding studies of the past five years. We highlight the progress made regarding this new concept of NKA and the various cardiac glycosides that influence it. Furthermore, we emphasize NKA's role in epithelial physiology, particularly its function as a receptor for cardiac glycosides that trigger intracellular signals regulating cell-cell contacts, proliferation, differentiation, and adhesion. We also analyze the role of NKA ß-subunits as cell adhesion molecules in glia and epithelial cells.

Microscopy, HPTLC, and LC-DAD-Q-ToF validation of nut-based weight-loss dietary supplements, Aleurites moluccanus (candlenut) and Bertholletia excelsa (Brazil nut).

Aleurites moluccanus (candlenut) and Bertholletia excelsa (Brazil nut) are marketed as dietary supplements for weight loss. These dietary supplements have been found to sometimes be adulterated with toxic nuts/seeds from Cascabela thevetia, commonly known as yellow oleander or lucky nut. This study emphasizes the key identification parameters to differentiate the genuine and adulterated nuts. Samples were obtained from authenticated sources of the nuts and from commercial sources of dietary supplements. This study examined 38 samples, including voucher and commercial samples. All eight commercial candlenut dietary supplement samples were adulterated. Additionally, two samples sold as Brazil nuts were also found to be adulterated. Other nuts were screened for the presence of Cardiac Glycosides, but none were found to be positive. The presence of yellow oleander was confirmed in all commercial dietary supplement samples marketed as candlenut as well as in commercial samples of Brazil nut. This study provides simple key identification characters using micro-morphology and histochemical localization of cardiac glycosides in the commercial nuts, HPTLC fingerprints, and LC-DAD-Q-ToF analytical parameters to detect and identify adulteration in commercial products.

The Na/K-ATPase role as a signal transducer in lung inflammation.

Acute respiratory distress syndrome (ARDS) is marked by damage to the capillary endothelium and alveolar epithelium following edema formation and cell infiltration. Currently, there are no effective treatments for severe ARDS. Pathologies such as sepsis, pneumonia, fat embolism, and severe trauma may cause ARDS with respiratory failure. The primary mechanism of edema clearance is the epithelial cells' Na/K-ATPase (NKA) activity. NKA is an enzyme that maintains the electrochemical gradient and cell homeostasis by transporting Na+ and K+ ions across the cell membrane. Direct injury on alveolar cells or changes in ion transport caused by infections decreases the NKA activity, loosening tight junctions in epithelial cells and causing edema formation. In addition, NKA acts as a receptor triggering signal transduction in response to the binding of cardiac glycosides. The ouabain (a cardiac glycoside) and oleic acid induce lung injury by targeting NKA. Besides enzymatic inhibition, the NKA triggers intracellular signal transduction, fostering proinflammatory cytokines production and contributing to lung injury. Herein, we reviewed and discussed the crucial role of NKA in edema clearance, lung injury, and intracellular signaling pathway activation leading to lung inflammation, thus putting the NKA as a protagonist in lung injury pathology.

Ouabain Effects on Human Anaplastic Thyroid Carcinoma 8505C Cells.

Anaplastic thyroid carcinoma (ATC) is a rare, but aggressive, carcinoma derived from follicular cells. While conventional treatments may improve patients' survival, the lethality remains high. Therefore, there is an urgent need for more effective ATC treatments. Cardiotonic steroids, such as ouabain, have been shown to have therapeutic potential in cancer treatment. Thus, we aimed to evaluate ouabain's effects in human anaplastic thyroid cells. For this, 8505C cells were cultured in the presence or absence of ouabain. Viability, cell death, cell cycle, colony formation and migratory ability were evaluated in ouabain-treated and control 8505C cells. The expression of differentiation and epithelial-to-mesenchymal transition (EMT) markers, as well as IL-6, TGFb1 and their respective receptors were also quantified in these same cells. Our results showed that ouabain in vitro decreased the number of viable 8505C cells, possibly due to an inhibition of proliferation. A reduction in migration was also observed in ouabain-treated 8505C cells. In contrast, decreased mRNA levels of PAX8 and TTF1 differentiation markers and increased levels of the N-cadherin EMT marker, as well as IL-6 and TGFb1, were found in ouabain-treated 8505C cells. In short, ouabain may have anti-proliferative and anti-migratory effect on 8505C cells, but maintains an aggressive and undifferentiated profile.

Antitumor effects of oleandrin in different types of cancers: Systematic review.

Oleandrin, a cardiac glycoside isolated from the leaves of Nerium oleander, has known effects on the heart. Evidence from recent studies have highlighted its potential for anticancer properties. Therefore, we aimed to investigate the effects of oleandrin on cancer cell proliferation, viability and apoptosis in vitro and in vivo. We performed a systematic search in six electronic databases up to Jan 2022. We extracted information about the effects of oleandrin on cell proliferation, cell viability, apoptosis and/or cell cycle arrest in in vitro studies, and the effects on tumor size and volume in animal experimental models. We have retrieved 775 scientific studies. 14 studies met the inclusion criteria. They investigated the effects of oleandrin on breast, lung, pancreatic, colon, prostate, colorectal, oral, ovarian, glioma, melanoma, glioblastoma, osteosarcoma, and histiocytic lymphoma cancers. Overall, in vitro studies demonstrated that oleandrin was able to inhibit cell proliferation, decrease cell viability, and induce apoptosis and/or cell cycle arrest. In addition, oleandrin had an effect on reducing mean tumor size and volume in animal studies. Oleandrin, as a cytotoxic agent, demonstrated antitumor effects in different types of cancers, however important clinical limitations remain a concern. These results encourage future studies to verify the applicability of oleandrin in antineoplastic therapeutic protocols human and veterinary medicine, the investigation of antimetastatic properties, as well as the potential increase in patient survival and the decrease of tumor markers.

Acerca de la muerte de Hernando de Magallanes: efectos de una flecha envenenada / The possible poisons contained in the arrow that killed Ferdinand Magellan

Ferdinand Magellan's maritime expedition that resulted in the circumnavigation of the Earth and the discovery of the strait that bears his name is among the greatest feats in history. The trip, which took more than three years, was not completed by Magellan, who died on the island of Mactan, Philippines in a scuffle with the locals. As reported in Magellan's voyage journal written by Pigafetta, Magellan died after receiving a poisoned arrow in his right leg. This study reviews the main compounds used by indigenous from the Philippines and Southeast Asian to poison their arrows, their agents, and effects. These poisons are mainly derived from Aconitum and other species, such as Strychnos, Lophopetalum, Beaumontia, and Strophanthus. They contain cardiac alkaloids and glycosides, which can produce neurological and cardiac effects in just a few minutes. We argue that these toxic effects hindered the withdrawal of Magellan from the beach, facilitating his death in hands of the locals.

Cytotoxic effect of carbohydrate derivatives of digitoxigenin involves modulation of plasma membrane Ca2+ -ATPase.

Cardiac glycosides, such as digoxin and digitoxin, are compounds that interact with Na+ /K+ -ATPase to induce anti-neoplastic effects; however, these cardiac glycosides have narrow therapeutic index. Thus, semi-synthetic analogs of digitoxin with modifications in the sugar moiety has been shown to be an interesting approach to obtain more selective and more effective analogs than the parent natural product. Therefore, the aim of this study was to assess the cytotoxic potential of novel digitoxigenin derivatives, digitoxigenin-α-L-rhamno-pyranoside (1) and digitoxigenin-α-L-amiceto-pyranoside (2), in cervical carcinoma cells (HeLa) and human diploid lung fibroblasts (Wi-26-VA4). In addition, we studied the anticancer mechanisms of action of these compounds by comparing its cytotoxic effects with the potential to modulate the activity of three P-type ATPases; Na+ /K+ -ATPase, sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA), and plasma membrane Ca2+ -ATPase (PMCA). Briefly, the results showed that compounds 1 and 2 were more cytotoxic and selectivity for HeLa tumor cells than the nontumor cells Wi-26-VA4. While the anticancer cytotoxicity in HeLa cells involves the modulation of Na+ /K+ -ATPase, PMCA and SERCA, the modulation of these P-type ATPases was completely absent in Wi-26-VA4 cells, which suggest the importance of their role in the cytotoxic effect of compounds 1 and 2 in HeLa cells. Furthermore, the compound 2 inhibited directly erythrocyte ghosts PMCA and both compounds were more cytotoxic than digitoxin in HeLa cells. These results provide a better understanding of the mode of action of the synthetic cardiac glycosides and highlights 1 and 2 as potential anticancer agents.

Intoxicación por adelfa, un caso poco frecuente / Oleander poisoning, a rare case

Introducción: Las intoxicaciones por plantas son infrecuentes, de complicada orientación diagnóstica, que en general, se dificulta la identificación de la planta, su potencial tóxico y el tratamiento específico. Entre ellas la adelfa, capaz de producir cuadros de intoxicación grave, como un caso consultado a la guardia del Centro Nacional de Toxicología. Objetivos: Presentar un caso clínico de intoxicación grave por adelfa. Caso clínico: Paciente adulto, con intranquilidad, vómitos, dolores abdominales, tensión arterial 150/90 mmHg, frecuencia cardiaca y respiratoria normales, refirió que había consumido vía oral y rectal una poción elaborada con una planta, como tratamiento antiparasitario. El médico de guardia decidió comunicarse con el Centro Nacional de Toxicología. Se identificó la planta como adelfa. A pesar de la aplicación de reposición de volumen, lavado gástrico y la administración de carbón activado; presentó bloqueo auriculoventricular, extrasístoles aisladas y bradicardia. Se suministró atropina endovenosa, luego se trasladó hacia la unidad de cuidados intensivos y posteriormente egresó. Conclusiones: El caso presentó una intoxicación aguda grave por adelfa, con un correcto diagnóstico y tratamiento, que requirió de la labor conjunta de los médicos del cuerpo de guardia del hospital, la terapia intensiva y del Centro Nacional de Toxicología(AU)

Introduction: Poisoning by plants is infrequent, with a complicated diagnostic orientation, which in general makes it difficult to identify the plant, its toxic potential and specific treatment. Among them the oleander, capable of producing serious intoxication, as a case consulted to the National Toxicology Center. Objectives: To present a clinical case of severe oleander poisoning. Clinical case: Adult patient with restlessness, vomiting, abdominal pain, blood pressure 150/90 mmHg, normal heart and respiratory rates, and reported that he had consumed orally and rectally a potion made with a plant, as an antiparasitic treatment. The doctor who assisted him decided to communicate with the National Toxicology Center. The plant was identified as oleander. Despite the application of volume replacement, gastric lavage and the administration of activated charcoal; the patient presented atrioventricular block, isolated extrasystoles and bradycardia, intravenous atropine was administered, and subsequent transfer to the intensive care unit, and later he was discharged. Conclusions: The case presented a severe acute oleander poisoning, there was correct diagnosis and treatment, which required the joint work of the doctors from hospital emergency, the intensive care unit and the National Toxicology Center(AU)

Na+/K+-ATPase as a Target of Cardiac Glycosides for the Treatment of SARS-CoV-2 Infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), identified for the first time in Wuhan, China, causes coronavirus disease 2019 (COVID-19), which moved from epidemic status to becoming a pandemic. Since its discovery in December 2019, there have been countless cases of mortality and morbidity due to this virus. Several compounds such as chloroquine, hydroxychloroquine, lopinavir-ritonavir, and remdesivir have been tested as potential therapies; however, no effective treatment is currently recommended by regulatory agencies. Some studies on respiratory non-enveloped viruses such as adenoviruses and rhinovirus and some respiratory enveloped viruses including human respiratory syncytial viruses, influenza A, parainfluenza, SARS-CoV, and SARS-CoV-2 have shown the antiviral activity of cardiac glycosides, correlating their effect with Na+/K+-ATPase (NKA) modulation. Cardiac glycosides are secondary metabolites used to treat patients with cardiac insufficiency because they are the most potent inotropic agents. The effects of cardiac glycosides on NKA are dependent on cell type, exposure time, and drug concentration. They may also cause blockage of Na+ and K+ ionic transport or trigger signaling pathways. The antiviral activity of cardiac glycosides is related to cell signaling activation through NKA inhibition. Nuclear factor kappa B (NFκB) seems to be an essential transcription factor for SARS-CoV-2 infection. NFκB inhibition by cardiac glycosides interferes directly with SARS-CoV-2 yield and inflammatory cytokine production. Interestingly, the antiviral effect of cardiac glycosides is associated with tyrosine kinase (Src) activation, and NFκB appears to be regulated by Src. Src is one of the main signaling targets of the NKA α-subunit, modulating other signaling factors that may also impair viral infection. These data suggest that Src-NFκB signaling modulated by NKA plays a crucial role in the inhibition of SARS-CoV-2 infection. Herein, we discuss the antiviral effects of cardiac glycosides on different respiratory viruses, SARS-CoV-2 pathology, cell signaling pathways, and NKA as a possible molecular target for the treatment of COVID-19.

Cytotoxicity of glucoevatromonoside alone and in combination with chemotherapy drugs and their effects on Na+,K+-ATPase and ion channels on lung cancer cells.

Cardiac glycosides (CGs) are useful drugs to treat cardiac illnesses and have potent cytotoxic and anticancer effects in cultured cells and animal models. Their receptor is the Na+,K+ ATPase, but other plasma membrane proteins might bind CGs as well. Herein, we evaluated the short- and long-lasting cytotoxic effects of the natural cardenolide glucoevatromonoside (GEV) on non-small-cell lung cancer H460 cells. We also tested GEV effects on Na+,K+ -ATPase activity and membrane currents, alone or in combination with selected chemotherapy drugs. GEV reduced viability, migration, and invasion of H460 cells spheroids. It also induced cell cycle arrest and death and reduced the clonogenic survival and cumulative population doubling. GEV inhibited Na+,K+-ATPase activity on A549 and H460 cells and purified pig kidney cells membrane. However, it showed no activity on the human red blood cell plasma membrane. Additionally, GEV triggered a Cl-mediated conductance on H460 cells without affecting the transient voltage-gated sodium current. The administration of GEV in combination with the chemotherapeutic drugs paclitaxel (PAC), cisplatin (CIS), irinotecan (IRI), and etoposide (ETO) showed synergistic antiproliferative effects, especially when combined with GEV + CIS and GEV + PAC. Taken together, our results demonstrate that GEV is a potential drug for cancer therapy because it reduces lung cancer H460 cell viability, migration, and invasion. Our results also reveal a link between the Na+,K+-ATPase and Cl- ion channels.

Design, synthesis and anti-tumor activities of carbamate derivatives of cinobufagin.

A series of cinobufagin-3-yl nitrogen-containing-carbamate derivatives were designed, synthesized, and evaluated for their proliferation inhibition activities. The structure-activity relationships suggested that the substituents at C-16 was a crucial factor for the potency and that follows this trends: acetic ester â‰« benzoic ester ≈ hydroxy > carbamate. Compounds 3f, 3g, 3h, and 3i exhibited significant in vitro antiproliferative activities against the eight tested tumor cell lines, with IC50 values ranging from 8.1 to 237.4 nM. Furthermore, 3g tartrate (3g-TA) significantly inhibited tumor growth by 64.5%, 83.9%, and 93.0% at a doses of 4, 6, 8 mg/kg/qod by ip, respectively.

Comparative Cardiotoxicity of Low Doses of Digoxin, Ouabain, and Oleandrin.

The aim of this study was to evaluate the comparative effects of CGs on heart physiology. Twenty-eight Wistar rats were distributed into four groups (n = 7), control group received NaCl 0.9% every 24 h for 21 days; treated groups received respectively 50 µg/kg of digoxin (DIG), ouabain (OUA) and oleandrin (OLE) every 24 h for 21 days. Serial ECGs were performed, as well as serum levels of creatinine kinase (CK), its MB fraction, troponin I (cTnI), calcium (Ca2+) and lactic dehydrogenase (LDH). Heart tissue was processed for histology, scanning electron microscopy and Western blot analysis for cTnI, brain natriuretic peptide (BNP), sodium potassium pump alpha-1 and alpha-2. Ventricle samples were also analyzed for thiobarbituric acid reactive substances and antioxidant enzymes (SOD, GPX, and CAT). ECGs showed decrease in QT and progressive shortening of QRS. No arrhythmias were observed. No significant differences were associated with CGs treatment and serum levels of CK, CK-MB, and cTnI. Only oleandrin increased LDH levels. Histological analysis showed degenerative changes and only oleandrin promoted moderate focal necrosis of cardiomyocytes. Scanning microscopy also confirmed the greatest effect of oleandrin, with rupture and shortening of cardiac fibers. The expression of troponin I and alpha-1 isoform were not altered, however, the protein levels of BNP and alpha-2 were higher in the groups that received oleandrin and ouabain in relation to the digoxin group. All GCs affected the production of ROS, without causing lipid peroxidation, through the activation of different antioxidant pathways. It is concluded that the administration of digoxin, ouabain, and oleandrin at 50 µg/kg for 21 days caused cardiovascular damage that represent an important limitation into its future use in heart failure and antineoplastic therapy.

Cardiac glycosides from Cascabela thevetioides by HPLC-MS analysis

Abstract The present work investigates the chemical composition of seeds of Cascabela thevetioides (Kunth) Lippold, an ornamental shrub of México. Six thevetia cardiac glycosides or thevetosides (thevetin A, B, and C, acetylthevetin A, B and C) were identified from the methanol extract of seeds of C. thevetioides by High-Performance Liquid Chromatography-Mass Spectrometry and by comparison of mass spectral fragmentation patterns. Enzymatic hydrolysis of a sample of thevetosides from methanol extract of seeds and subsequent High-Performance Liquid Chromatography-Mass Spectrometry analysis yielded the monoglycosides neriifolin, acetylneriifolin and acetylperuvoside, previously reported for this plant. For the fisrt time thevetin A, B and C, and acetylthevetin A, B and C are reported as components of seeds of C. thevetioides.

An outbreak of poisoning by Kalanchoe blossfeldiana in cattle in northeastern Brazil.

In the world, Kalanchoe species are primarily ornamentals and houseplants, but some have escaped cultivation and can be found in the field. In Latin America, there are no reports of spontaneous poisoning by Kalanchoe species in animals. This study aimed to describe the epidemiological, clinical, and pathological aspects of an outbreak of poisoning by Kalanchoe blossfeldiana in cattle in the semiarid region of Pernambuco, Brazil. Epidemiological and clinical data were obtained from the owner and veterinarian during technical visits. Prunings of this plant were disposed of in a pasture with a shortness of forage. Seventeen cattle had clinical signs, and thirteen died 4-5 days after the first clinical signs were observed. Clinical signs and gross and histological lesions include gastrointestinal, cardiovascular, and neuromuscular disorders. Kalanchoe spp. contain cardiotoxic glycosides, and the clinical signs and lesions in cattle of this outbreak were consistent with poisoning by plants that contain these toxins.

Anticancer and Immunogenic Properties of Cardiac Glycosides.

Cardiac glycosides (CGs) are natural compounds widely used in the treatment of several cardiac conditions and more recently have been recognized as potential antitumor compounds. They are known to be ligands for Na/K-ATPase, which is a promising drug target in cancer. More recently, in addition to their antitumor effects, it has been suggested that CGs activate tumor-specific immune responses. This review summarizes the anticancer aspects of CGs as new strategies for immunotherapy and drug repositioning (new horizons for old players), and the possible new targets for CGs in cancer cells.

Dogs poisoned with Nerium oleander fresh leaves: clinical and electrocardiographic findings / Cães intoxicados com folhas frescas de Nerium oleander: achados clínicos e eletrocardiográficos

Nerium oleander is distributed worldwide, mainly in tropical and subtropical regions. These shrubs are frequently used as ornamental plants. However, they contain more than 30 cardiac glycosides that can cause serious toxic effects in dogs. The objective of this study was to report the clinical and electrocardiographic alterations in dogs experimentally poisoned with N. oleander. Ten adult, healthy, mixed-breed dogs weighing 10-25kg and aged 3-6 years were selected for the study. We orally administered 0.25g kg-1 of fresh ground leaves of N. oleander to the dogs. No dog died after the ingestion, but all exhibited signs of poisoning such as vomiting, sialorrhea, nausea, apathy, conjunctiva congestion, dehydration, abdominal pain, tremors, diarrhea, loss of appetite, and tenesmus. Electrocardiogram revealed occurrence of several types of arrhythmias: sinus bradycardia, second-degree atrioventricular block, paroxysmal ventricular tachycardia, and ventricular premature complexes. Systolic blood pressure, as well as heart rate, decreased in the first 24 hours. The present study concluded that a single dose of 0.25g kg-1 of N. oleander green leaves is sufficient to cause a moderate intoxication in dogs, with nonspecific clinical changes mainly related to the digestive system and heart rate, thus demonstrating the importance of this type of intoxication in the list of differential diagnoses of small animals routine.(AU)

O Nerium oleander é uma planta com ampla distribuição mundial, principalmente em regiões tropicais e subtropicais. Esses arbustos são frequentemente usados como plantas ornamentais e possuem mais de 30 glicosídeos cardíacos causadores do quadro clínico de intoxicação em caninos. Sabendo-se disso, este artigo teve por objetivo a avaliar as alterações clínicas e eletrocardiográficas, nos animais intoxicados experimentalmente com N. oleander. Foram utilizados 10 cães adultos, hígidos, sem raça definida, com 10 a 25kg de peso, de 3 a 6 anos de idade. Os animais receberam uma única dose de 0,25g kg-1 de peso, de folhas frescas de N. oleander. Nenhum dos animais do experimento veio a óbito. Os sinais clínicos observados foram vômito, sialorréia, náuseas, apatia, conjuntiva ocular congesta, desidratação, dor abdominal, tremores, diarreia, inapetência e tenesmo. Pela análise do eletrocardiograma encontraram-se arritmias como: bradicardia sinusal, bloqueios atrioventriculares de segundo grau, taquicardia ventricular paroxística e complexo ventricular prematuro. A pressão arterial sistólica diminui nas primeiras 24 horas, assim como a frequência cardíaca. Concluiu-se com o presente estudo que uma única dose de 0,25g kg-1 de folhas verdes de N. oleander é suficiente para causar um quadro moderado de intoxicação em cães, com alterações clínicas inespecíficas principalmente relacionadas ao sistema digestório e no ritmo cardíaco, mostrando a importância deste tipo de intoxicação na lista de diagnósticos diferenciais da rotina de pequenos animais.(AU)

Dogs poisoned with Nerium oleander fresh leaves: clinical and electrocardiographic findings / Cães intoxicados com folhas frescas de Nerium oleander: achados clínicos e eletrocardiográficos

Nerium oleander is distributed worldwide, mainly in tropical and subtropical regions. These shrubs are frequently used as ornamental plants. However, they contain more than 30 cardiac glycosides that can cause serious toxic effects in dogs. The objective of this study was to report the clinical and electrocardiographic alterations in dogs experimentally poisoned with N. oleander. Ten adult, healthy, mixed-breed dogs weighing 10-25kg and aged 3-6 years were selected for the study. We orally administered 0.25g kg-1 of fresh ground leaves of N. oleander to the dogs. No dog died after the ingestion, but all exhibited signs of poisoning such as vomiting, sialorrhea, nausea, apathy, conjunctiva congestion, dehydration, abdominal pain, tremors, diarrhea, loss of appetite, and tenesmus. Electrocardiogram revealed occurrence of several types of arrhythmias: sinus bradycardia, second-degree atrioventricular block, paroxysmal ventricular tachycardia, and ventricular premature complexes. Systolic blood pressure, as well as heart rate, decreased in the first 24 hours. The present study concluded that a single dose of 0.25g kg-1 of N. oleander green leaves is sufficient to cause a moderate intoxication in dogs, with nonspecific clinical changes mainly related to the digestive system and heart rate, thus demonstrating the importance of this type of intoxication in the list of differential diagnoses of small animals routine.

O Nerium oleander é uma planta com ampla distribuição mundial, principalmente em regiões tropicais e subtropicais. Esses arbustos são frequentemente usados como plantas ornamentais e possuem mais de 30 glicosídeos cardíacos causadores do quadro clínico de intoxicação em caninos. Sabendo-se disso, este artigo teve por objetivo a avaliar as alterações clínicas e eletrocardiográficas, nos animais intoxicados experimentalmente com N. oleander. Foram utilizados 10 cães adultos, hígidos, sem raça definida, com 10 a 25kg de peso, de 3 a 6 anos de idade. Os animais receberam uma única dose de 0,25g kg-1 de peso, de folhas frescas de N. oleander. Nenhum dos animais do experimento veio a óbito. Os sinais clínicos observados foram vômito, sialorréia, náuseas, apatia, conjuntiva ocular congesta, desidratação, dor abdominal, tremores, diarreia, inapetência e tenesmo. Pela análise do eletrocardiograma encontraram-se arritmias como: bradicardia sinusal, bloqueios atrioventriculares de segundo grau, taquicardia ventricular paroxística e complexo ventricular prematuro. A pressão arterial sistólica diminui nas primeiras 24 horas, assim como a frequência cardíaca. Concluiu-se com o presente estudo que uma única dose de 0,25g kg-1 de folhas verdes de N. oleander é suficiente para causar um quadro moderado de intoxicação em cães, com alterações clínicas inespecíficas principalmente relacionadas ao sistema digestório e no ritmo cardíaco, mostrando a importância deste tipo de intoxicação na lista de diagnósticos diferenciais da rotina de pequenos animais.

Anticancer potential of Thevetia peruviana fruit methanolic extract.

BACKGROUND: Thevetia peruviana (Pers.) K. Schum or Cascabela peruviana (L.) Lippold (commonly known as ayoyote, codo de fraile, lucky nut, or yellow oleander), native to Mexico and Central America, is a medicinal plant used traditionally to cure diseases like ulcers, scabies, hemorrhoids and dissolve tumors. The purpose of this study was to evaluate the cytotoxic, antiproliferative and apoptotic activity of methanolic extract of T. peruviana fruits on human cancer cell lines. METHODS: The cytotoxic activity of T. peruviana methanolic extract was carried out on human breast, colorectal, prostate and lung cancer cell lines and non-tumorigenic control cells (fibroblast and Vero), using the MTT assay. For proliferation and motility, clonogenic and wound-healing assays were performed. Morphological alterations were monitored by trypan blue exclusion, as well as DNA fragmentation and AO/EB double staining was performed to evaluate apoptosis. The extract was separated using flash chromatography, and the resulting fractions were evaluated on colorectal cancer cells for their cytotoxic activity. The active fractions were further analyzed through mass spectrometry. RESULTS: The T. peruviana methanolic extract exhibited cytotoxic activity on four human cancer cell lines: prostate, breast, colorectal and lung, with values of IC50 1.91 ± 0.76, 5.78 ± 2.12, 6.30 ± 4.45 and 12.04 ± 3.43 µg/mL, respectively. The extract caused a significant reduction of cell motility and colony formation on all evaluated cancer cell lines. In addition, morphological examination displayed cell size reduction, membrane blebbing and detachment of cells, compared to non-treated cancer cell lines. The T. peruviana extract induced apoptotic cell death, which was confirmed by DNA fragmentation and AO/EB double staining. Fractions 4 and 5 showed the most effective cytotoxic activity and their MS analysis revealed the presence of the secondary metabolites: thevetiaflavone and cardiac glycosides. CONCLUSION: T. peruviana extract has potential as natural anti-cancer product with critical effects in the proliferation, motility, and adhesion of human breast and colorectal cancer cells, and apoptosis induction in human prostate and lung cancer cell lines, with minimal effects on non-tumorigenic cell lines.

Dogs poisoned with Nerium oleander fresh leaves: clinical and electrocardiographic findings / Cães intoxicados com folhas frescas de Nerium oleander: achados clínicos e eletrocardiográficos

ABSTRACT: Nerium oleander is distributed worldwide, mainly in tropical and subtropical regions. These shrubs are frequently used as ornamental plants. However, they contain more than 30 cardiac glycosides that can cause serious toxic effects in dogs. The objective of this study was to report the clinical and electrocardiographic alterations in dogs experimentally poisoned with N. oleander. Ten adult, healthy, mixed-breed dogs weighing 10-25kg and aged 3-6 years were selected for the study. We orally administered 0.25g kg-1 of fresh ground leaves of N. oleander to the dogs. No dog died after the ingestion, but all exhibited signs of poisoning such as vomiting, sialorrhea, nausea, apathy, conjunctiva congestion, dehydration, abdominal pain, tremors, diarrhea, loss of appetite, and tenesmus. Electrocardiogram revealed occurrence of several types of arrhythmias: sinus bradycardia, second-degree atrioventricular block, paroxysmal ventricular tachycardia, and ventricular premature complexes. Systolic blood pressure, as well as heart rate, decreased in the first 24 hours. The present study concluded that a single dose of 0.25g kg-1 of N. oleander green leaves is sufficient to cause a moderate intoxication in dogs, with nonspecific clinical changes mainly related to the digestive system and heart rate, thus demonstrating the importance of this type of intoxication in the list of differential diagnoses of small animals routine.

RESUMO: O Nerium oleander é uma planta com ampla distribuição mundial, principalmente em regiões tropicais e subtropicais. Esses arbustos são frequentemente usados como plantas ornamentais e possuem mais de 30 glicosídeos cardíacos causadores do quadro clínico de intoxicação em caninos. Sabendo-se disso, este artigo teve por objetivo a avaliar as alterações clínicas e eletrocardiográficas, nos animais intoxicados experimentalmente com N. oleander. Foram utilizados 10 cães adultos, hígidos, sem raça definida, com 10 a 25kg de peso, de 3 a 6 anos de idade. Os animais receberam uma única dose de 0,25g kg-1 de peso, de folhas frescas de N. oleander. Nenhum dos animais do experimento veio a óbito. Os sinais clínicos observados foram vômito, sialorréia, náuseas, apatia, conjuntiva ocular congesta, desidratação, dor abdominal, tremores, diarreia, inapetência e tenesmo. Pela análise do eletrocardiograma encontraram-se arritmias como: bradicardia sinusal, bloqueios atrioventriculares de segundo grau, taquicardia ventricular paroxística e complexo ventricular prematuro. A pressão arterial sistólica diminui nas primeiras 24 horas, assim como a frequência cardíaca. Concluiu-se com o presente estudo que uma única dose de 0,25g kg-1 de folhas verdes de N. oleander é suficiente para causar um quadro moderado de intoxicação em cães, com alterações clínicas inespecíficas principalmente relacionadas ao sistema digestório e no ritmo cardíaco, mostrando a importância deste tipo de intoxicação na lista de diagnósticos diferenciais da rotina de pequenos animais.

A New Animal Model to Study Endogenous Cardiotonic Steroids and the Progression of Cardiovascular Events in Salt-Sensitive Hypertension.

The Dahl salt-sensitive rat is a well-established model to study essential hypertension. We first described a subgroup of these rats based on the unique response pattern in systolic blood pressure during the first weeks of exposure to a high salt diet that included cataract formation. We classified this group as cataract-prone Dahl salt-sensitive rat. We also were able to predict and prevent cataract formation in these rats. Further studies showed an inhibition of lens Na, K-ATPase activity which may be in part responsible for the cataract formation. Other studies in Dahl salt-sensitive rats maintained on a high salt diet have also shown decreased Na, K-ATPase activity in several tissues and increased levels of endogenous circulating Na, K pump inhibitors. For over 20 years, endogenous cardiotonic steroids have been postulated to inhibit Na, K-ATPase in both humans as well as in experimental animal models of hypertension. Recent findings have shown results suggesting that there are several forms of cardiotonic steroids with minor differences in structural functionalities, site of production, and specific pump selectivity. We present original data that supports a role for cardiotonic steroids in disease progression related to increased salt-sensitivity. We found increased levels of free endogenous cardiotonic steroids in those rats that were classified as cataract-prone according to their initial systolic blood pressure response to a high salt intake when compared to non-cataract prone Dahl salt-sensitive rats and their control Dahl salt-resistant rats. The cataract-prone Dahl salt-sensitive rat is an animal model that can help and contribute to open a new door to possibly elucidate the role of endogenous cardiotonic steroids in the pathogenesis and progression of diseases related to salt-sensitive hypertension.