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1.
Biomedica ; 44(1): 16-34, 2024 03 31.
Article in English, Spanish | MEDLINE | ID: mdl-38648344

ABSTRACT

Paraquat®, or N,N'-dimethyl-4,4'-bipyridinium dichloride, is a bipyridyl compound used as a non-selective herbicide and desiccant that can cause acute poisoning through all routes of exposure. There is no known antidote, and the available treatments are based on avoiding its absorption and timely removing it, in adults and children. We describe a case series of 14 pediatric patients from the department of Cauca, Colombia, with acute intoxication after oral intake of paraquat. Patients were referred to a medium-high complexity hospital in southwestern Colombia and treated according to an institutional protocol for acute paraquat poisoning. Acute paraquat poisoning after oral ingestion is associated with a high mortality rate, even with timely medical attention, as the compound has no known antidote and quickly reaches systemic concentrations for fulminant poisoning. Based on the available literature, our center has proposed a clinical protocol including early standard management, immunosuppressive and antioxidant treatments, and systemic removal techniques. This protocol suggests an adequate approach to acute paraquat poisoning in the pediatric population.


El dicloruro de 1,1'-dimetil-4,4'-bipiridilo (Paraquat®) es un compuesto químico de la familia de las piridinas, utilizado como herbicida no selectivo y desecante. Este compuesto puede causar intoxicación aguda por todas las vías de exposición. En el momento, no hay un antídoto conocido y los tratamientos disponibles, incluidos los pediátricos, se basan en contrarrestar su absorción y propiciar su remoción oportuna. Se describe una serie de casos de 14 pacientes pediátricos, procedentes en su mayoría del departamento del Cauca, con intoxicación aguda por ingestión de paraquat. Los pacientes fueron remitidos y atendidos en un hospital de mediana a alta complejidad en el suroccidente colombiano, con un protocolo institucional para el manejo de la intoxicación aguda por el herbicida. La intoxicación aguda con paraquat por vía oral se asocia con una alta tasa de mortalidad, aún con atención médica oportuna, pues fácilmente se alcanzan concentraciones sistémicas para ser fulminante. Basado en la literatura disponible, el Hospital Universitario San José ha propuesto un protocolo clínico ­adecuado para la intoxicación aguda por paraquat en población pediátrica­ que incluye manejo estándar temprano, tratamiento inmunosupresor y antioxidante, y técnicas para su remoción sistémica.


Subject(s)
Algorithms , Herbicides , Paraquat , Humans , Paraquat/poisoning , Child , Female , Male , Child, Preschool , Adolescent , Herbicides/poisoning , Poisoning/therapy , Poisoning/drug therapy , Colombia , Acute Disease , Infant , Antioxidants/therapeutic use , Clinical Protocols , Antidotes/therapeutic use
3.
Curr Med Chem ; 30(36): 4149-4166, 2023.
Article in English | MEDLINE | ID: mdl-36239718

ABSTRACT

Organophosphorus compounds (OP) make up an important class of inhibitors, mostly employed as pesticides, even as chemical weapons. These toxic substances act through the inhibition of the acetylcholinesterase (AChE) enzyme, which results in elevated synaptic acetylcholine (ACh) levels, leading to serious adverse effects under the cholinergic syndrome. Many reactivators have been developed to combat the toxic effects of these AChE inhibitors. In this line, the oximes highlight because of their good reactivating power of cholinesterase enzymes. To date, no universal antidotes can reactivate AChE inhibited by any OP agent. This review summarizes the intoxication process by neurotoxic OP agents, along with the development of reactivators capable of reversing their effects, approaching aspects like the therapeutic and toxicological profile of these antidotes. Computational methods and conscious in vitro studies, capable of significantly predicting the toxicological profile of these drug candidates, might support the process of development of these reactivators before entering in vivo studies in animals, and then clinical trials. These approaches can assist in the design of safer and more effective molecules, reducing related cost and time for the process.


Subject(s)
Antidotes , Cholinesterase Reactivators , Animals , Antidotes/pharmacology , Antidotes/therapeutic use , Antidotes/chemistry , Acetylcholinesterase/chemistry , Cholinesterase Reactivators/therapeutic use , Cholinesterase Reactivators/toxicity , Organophosphorus Compounds , Oximes/therapeutic use , Oximes/toxicity , Cholinesterase Inhibitors/toxicity
4.
Rev Med Chil ; 147(1): 73-82, 2019.
Article in Spanish | MEDLINE | ID: mdl-30848768

ABSTRACT

Direct oral anticoagulants (DOACs), including the direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors rivaroxaban, apixaban and edoxaban have at least comparable efficacy as vitamin K antagonists along with a better safety profile, reflected by a lower incidence of intracranial hemorrhage. Specific reversal agents have been developed in recent years. Namely, idarucizumab, a specific antidote for dabigatran, is currently approved in most countries. Andexanet, which reverses factor Xa inhibitors, has been recently approved by the FDA, and ciraparantag, a universal antidote targeted to reverse all DOACs, is still under investigation. In this review we provide an update on the pharmacology of DOACs, the risk of hemorrhagic complications associated with their use, the measurement of their anticoagulant effect and the reversal strategies in case of DOAC-associated bleeding.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Antithrombins/administration & dosage , Antithrombins/adverse effects , Blood Coagulation Factors/therapeutic use , Hemorrhage/chemically induced , Hemorrhage/therapy , Administration, Oral , Antidotes/therapeutic use , Dabigatran/administration & dosage , Dabigatran/adverse effects , Humans , Pyrazoles/administration & dosage , Pyrazoles/adverse effects , Pyridines/administration & dosage , Pyridines/adverse effects , Pyridones/administration & dosage , Pyridones/adverse effects , Risk Factors , Rivaroxaban/administration & dosage , Rivaroxaban/adverse effects , Thiazoles/administration & dosage , Thiazoles/adverse effects
6.
Rev. méd. Chile ; 147(1): 73-82, 2019. tab, graf
Article in Spanish | LILACS | ID: biblio-991375

ABSTRACT

Direct oral anticoagulants (DOACs), including the direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors rivaroxaban, apixaban and edoxaban have at least comparable efficacy as vitamin K antagonists along with a better safety profile, reflected by a lower incidence of intracranial hemorrhage. Specific reversal agents have been developed in recent years. Namely, idarucizumab, a specific antidote for dabigatran, is currently approved in most countries. Andexanet, which reverses factor Xa inhibitors, has been recently approved by the FDA, and ciraparantag, a universal antidote targeted to reverse all DOACs, is still under investigation. In this review we provide an update on the pharmacology of DOACs, the risk of hemorrhagic complications associated with their use, the measurement of their anticoagulant effect and the reversal strategies in case of DOAC-associated bleeding.


Subject(s)
Humans , Blood Coagulation Factors/therapeutic use , Antithrombins/administration & dosage , Antithrombins/adverse effects , Antibodies, Monoclonal, Humanized/therapeutic use , Hemorrhage/chemically induced , Hemorrhage/therapy , Pyrazoles/administration & dosage , Pyrazoles/adverse effects , Pyridines/administration & dosage , Pyridines/adverse effects , Pyridones/administration & dosage , Pyridones/adverse effects , Thiazoles/administration & dosage , Thiazoles/adverse effects , Administration, Oral , Risk Factors , Rivaroxaban/administration & dosage , Rivaroxaban/adverse effects , Dabigatran/administration & dosage , Dabigatran/adverse effects , Antidotes/therapeutic use
7.
Trans R Soc Trop Med Hyg ; 112(4): 188-192, 2018 04 01.
Article in English | MEDLINE | ID: mdl-29788193

ABSTRACT

Background: The purpose of this study was to estimate the frequency and describe the adverse drug reactions (ADRs) associated with the classic treatment of ocular toxoplasmosis (OT), namely sulfadiazine, pyrimethamine, corticosteroids and folinic acid. Methods: We performed a descriptive study of a prospective cohort of patients with OT treated with the classic therapy. Data were collected during medical consultations and treatment. Results: Of the 147 patients studied, 85% developed one or more ADR. Women presented more ADRs than men (95% vs 77%). Of the total reactions (n=394), 82% were mild, but we found one life-threatening event (Stevens-Johnson syndrome). The most frequent types (71%) of ADRs were gastrointestinal, skin and neurological or psychiatric. The majority of ADRs (90.3%) occurred before the second week of treatment. A third of the patients were treated for the ADR and 10% dropped out of OT treatment. Most (70%) of the ADRs were characterized as being probably caused by the drugs and may be associated with prednisone, sulfadiazine and sulfadiazine/prednisone. Six percent of ADRs were not previously described, such as taste alteration, constipation/bloating, dyspnoea, sweating and somnolence. Conclusions: Our results suggest a high rate of ADRs to OT classic treatment, which requires careful follow-up in order to identify and treat ADRs early.


Subject(s)
Antidotes/adverse effects , Antiprotozoal Agents/adverse effects , Drug-Related Side Effects and Adverse Reactions/epidemiology , Toxoplasmosis, Ocular/drug therapy , Adolescent , Adrenal Cortex Hormones/adverse effects , Adrenal Cortex Hormones/therapeutic use , Adult , Adverse Drug Reaction Reporting Systems , Aged , Antidotes/therapeutic use , Antiprotozoal Agents/therapeutic use , Brazil/epidemiology , Comorbidity , Drug-Related Side Effects and Adverse Reactions/therapy , Female , Humans , Leucovorin/adverse effects , Leucovorin/therapeutic use , Male , Middle Aged , Prospective Studies , Pyrimethamine/adverse effects , Pyrimethamine/therapeutic use , Sulfadiazine/adverse effects , Sulfadiazine/therapeutic use , Toxoplasmosis, Ocular/epidemiology , Treatment Outcome , Young Adult
8.
Curr Drug Targets ; 19(13): 1550-1559, 2018.
Article in English | MEDLINE | ID: mdl-29611486

ABSTRACT

Evidence-based review of the existing literature ultimately recommends stocking of Methylene Blue (MB) as an emergency antidote in the United States. The same is reported around the world in Japan, Greece, Italy and Canada. The observation that MB is always present as the main antidote required in emergency and critical care units calls for a revisit on its effects on the NO/cGMP system to reemphasize its multisystem actions. Therefore, the present review aimed to display the role of MB in emergency units, concerning: 1) Polytrauma and circulatory shock; 2) Neuroprotection, 3) Anaphylaxis and, 4) Overdose and poisoning.


Subject(s)
Antidotes/therapeutic use , Critical Care/methods , Methylene Blue/therapeutic use , Anaphylaxis/drug therapy , Clinical Trials as Topic , Drug Overdose/drug therapy , Emergency Service, Hospital , Evidence-Based Medicine , Humans , Multiple Trauma/drug therapy , Nervous System Diseases/drug therapy , Poisoning/drug therapy
9.
Arch. pediatr. Urug ; 88(6)oct. 2017. ilus
Article in Spanish | BVSNACUY | ID: bnu-181685

ABSTRACT

La metahemoglobinemia es un síndrome clínico dado por la presencia de una forma aberrante de hemoglobina, ocasionada por diversos agentes oxidantes. Se describe un caso clínico de metahemoglobinemia severa asociada a la ingesta de puré de acelgas con alto contenido en nitratos y nitritos. Paciente de un año, con antecedentes de comunicación interauricular (CIA), que presentó un cambio en coloración de la piel 7 h antes, en forma progresiva, acompañado de vómitos. Ingresó al Departamento de Emergencia con cianosis generalizada que no mejoró con oxigenoterapia, taquicardia y tendencia a hipotensión arterial. En cuidados intensivos se realizó ecocardiograma que evidenció CIA sin repercusión hemodinámica. Metahemoglobinemia 37%. Se realizó dosis de azul de metileno al 1% por vía intravenosa, con franca mejoría clínica a la hora de la administración del antídoto y descenso de niveles de metahemoglobina. Alta médica a las 36 horas del ingreso. Existía una relación cronológica entre la exposición a nitratos por ingesta de un puré de acelgas y la aparición del cuadro. Los niveles de nitratos hallados en dicho alimento fueron muy elevados considerando estándares internacionales, lo que sumado a una inadecuada conservación del alimento cocido los días previos, permitió confirmar el planteo etiológico realizado. Resulta importante sospechar esta entidad patológica poco frecuente frente a cianosis que no mejora con oxígeno, y prevenir cuadros similares al descrito mediante una adecuada manipulación y conservación de las verduras con alto contenido en nitratos.


Subject(s)
Humans , Female , Infant , Methemoglobinemia/diagnosis , Methemoglobinemia/drug therapy , Methylene Blue/therapeutic use , Enzyme Inhibitors/therapeutic use , Antidotes/therapeutic use , Beta vulgaris/poisoning , Nitrates/poisoning , Methemoglobinemia/complications , Cyanosis/etiology , Foodborne Diseases/diagnosis , Foodborne Diseases/drug therapy
10.
Arch. pediatr. Urug ; 88(6): 335-340, oct. 2017. tab
Article in Spanish | LILACS | ID: biblio-887803

ABSTRACT

La metahemoglobinemia es un síndrome clínico dado por la presencia de una forma aberrante de hemoglobina, ocasionada por diversos agentes oxidantes. Se describe un caso clínico de metahemoglobinemia severa asociada a la ingesta de puré de acelgas con alto contenido en nitratos y nitritos. Paciente de un año, con antecedentes de comunicación interauricular (CIA), que presentó un cambio en coloración de la piel 7 h antes, en forma progresiva, acompañado de vómitos. Ingresó al Departamento de Emergencia con cianosis generalizada que no mejoró con oxigenoterapia, taquicardia y tendencia a hipotensión arterial. En cuidados intensivos se realizó ecocardiograma que evidenció CIA sin repercusión hemodinámica. Metahemoglobinemia 37%. Se realizó dosis de azul de metileno al 1% por vía intravenosa, con franca mejoría clínica a la hora de la administración del antídoto y descenso de niveles de metahemoglobina. Alta médica a las 36 horas del ingreso. Existía una relación cronológica entre la exposición a nitratos por ingesta de un puré de acelgas y la aparición del cuadro. Los niveles de nitratos hallados en dicho alimento fueron muy elevados considerando estándares internacionales, lo que sumado a una inadecuada conservación del alimento cocido los días previos, permitió confirmar el planteo etiológico realizado. Resulta importante sospechar esta entidad patológica poco frecuente frente a cianosis que no mejora con oxígeno, y prevenir cuadros similares al descrito mediante una adecuada manipulación y conservación de las verduras con alto contenido en nitratos.


Methemoglobinemia is a clinical syndrome due to the presence of an aberrant form of hemoglobin, caused by various oxidizing agents. The study reports a case of severe methemoglobinemia associated with the ingestion of chard puree with high levels of nitrates and nitrites. A 1-year-old patient with a history of atrial septal defect (ASD), who progressively showed change of skin color 7 hours earlier, accompanied by vomiting. She was admitted to the Emergency Department with generalized cyanosis not improving with oxygen therapy, tachycardia and tendency to hypotension. In the intensive care unit, an echocardiogram showed ASD without hemodynamic complications. Methemoglobinemia 37%. A 1% methylene blue dose was administered intravenously, with clinical improvement one hour after antidote administration and decrease in methemoglobin levels. Medical discharge at 36 hours of admission. There was a chronological relationship between nitrates exposure by ingestion of chard puree and the clinical onset of methemoglobinemia. The toxic cause was confirmed after high nitrates levels were found in this vegetable considering international standards, and an inadequate preservation of the cooked chard on previous days. It is important to suspect this rare pathological entity when cyanosis fails to improve with oxygen, and to prevent poisonings similar to those described by an adequate manipulation and preservation of vegetables with high nitrate levels.


Subject(s)
Humans , Beta vulgaris/poisoning , Enzyme Inhibitors/therapeutic use , Methemoglobinemia , Methemoglobinemia/diagnosis , Methylene Blue/therapeutic use , Antidotes/therapeutic use , Nitrates/poisoning , Cyanosis/etiology , Foodborne Diseases , Foodborne Diseases/diagnosis , Methemoglobinemia/complications
11.
Adv Neurobiol ; 18: 53-83, 2017.
Article in English | MEDLINE | ID: mdl-28889263

ABSTRACT

The antagonism of mercury toxicity by selenium has been well documented. Mercury is a toxic metal, widespread in the environment. The main target organs (kidneys, lungs, or brain) of mercury vary depending on its chemical forms (inorganic or organic). Selenium is a semimetal essential to mammalian life as part of the amino acid selenocysteine, which is required to the synthesis of the selenoproteins. This chapter has the aim of disclosing the role of selenide or hydrogen selenide (Se-2 or HSe-) as central metabolite of selenium and as an important antidote of the electrophilic mercury forms (particularly, Hg2+ and MeHg). Emphasis will be centered on the neurotoxicity of electrophile forms of mercury and selenium. The controversial participation of electrophile mercury and selenium forms in the development of some neurodegenerative disease will be briefly presented. The potential pharmacological use of organoseleno compounds (Ebselen and diphenyl diselenide) in the treatment of mercury poisoning will be considered. The central role of thiol (-SH) and selenol (-SeH) groups as the generic targets of electrophile mercury forms and the need of new in silico tools to guide the future biological researches will be commented.


Subject(s)
Brain/metabolism , Mercury Poisoning, Nervous System/metabolism , Neurotoxicity Syndromes/etiology , Selenium/poisoning , Antidotes/therapeutic use , Azoles/therapeutic use , Benzene Derivatives/therapeutic use , Humans , Isoindoles , Mercury Poisoning/drug therapy , Mercury Poisoning/metabolism , Mercury Poisoning, Nervous System/drug therapy , Neurotoxicity Syndromes/drug therapy , Neurotoxicity Syndromes/metabolism , Organoselenium Compounds/therapeutic use , Selenoproteins/metabolism
12.
Acad Emerg Med ; 24(9): 1088-1098, 2017 09.
Article in English | MEDLINE | ID: mdl-28472554

ABSTRACT

BACKGROUND: Hydrogen sulfide (H2 S) is a potentially deadly gas that naturally occurs in petroleum and natural gas. The Occupational Health and Safety Administration cites H2 S as a leading cause of workplace gas inhalation deaths. Mass casualties of H2 S toxicity may be caused by exposure from industrial accidents or release from oil field sites. H2 S is also an attractive terrorism tool because of its high toxicity and ease with which it can be produced. Several potential antidotes have been proposed for hydrogen sulfide poisoning but none have been completely successful. OBJECTIVE: The objective was to compare treatment response assessed by the time to spontaneous ventilation among groups of swine with acute H2 S-induced apnea treated with intravenous (IV) cobinamide (4 mg/kg in 0.8 mL of 225 mmol/L solution), IV hydroxocobalamin (4 mg/kg in 5 mL of saline), or saline alone. METHODS: Twenty-four swine (45-55 kg) were anesthetized, intubated, and instrumented with continuous femoral and pulmonary artery pressure monitoring. After stabilization, anesthesia was adjusted such that animals would spontaneously ventilate with an FiO2 of 0.21. Sodium hydrosulfide (NaHS; concentration of 8 mg/mL) was begun at 1 mg/kg/min until apnea was confirmed for 20 seconds by capnography. This infusion rate was sustained for 1.5 minutes postapnea and then decreased to a maintenance rate for the remainder of the study to replicate sustained clinical exposure. Animals were randomly assigned to receive cobinamide (4 mg/kg), hydroxocobalamin (4 mg/kg), or saline and monitored for 60 minutes beginning 1 minute postapnea. G* power analysis using the Z-test determined that equal group sizes of eight animals were needed to achieve a power of 80% in detecting a 50% difference in return to spontaneous ventilations at α = 0.05. RESULTS: There were no significant differences in baseline variables. Moreover, there were no significant differences in the mg/kg dose of NaHS (5.6 mg/kg; p = 0.45) required to produce apnea. Whereas all of the cobinamide-treated animals survived (8/8), none of the control (0/8) or hydroxocobalamin (0/8)-treated animals survived. Mean (±SD) time to spontaneous ventilation in the cobinamide-treated animals was 3.2 (±1.1) minutes. CONCLUSIONS: Cobinamide successfully rescued the severely NaHS-poisoned swine from apnea in the absence of assisted ventilation.


Subject(s)
Antidotes/therapeutic use , Apnea/drug therapy , Cobamides/therapeutic use , Hydrogen Sulfide/poisoning , Hydroxocobalamin/therapeutic use , Administration, Intravenous , Animals , Apnea/chemically induced , Cobamides/administration & dosage , Cobamides/pharmacology , Disease Models, Animal , Female , Hydroxocobalamin/pharmacology , Sodium Chloride/administration & dosage , Sulfides/administration & dosage , Sus scrofa , Swine
13.
Ann Emerg Med ; 69(6): 718-725.e4, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28041825

ABSTRACT

STUDY OBJECTIVE: The 2 antidotes for acute cyanide poisoning in the United States must be administered by intravenous injection. In the out-of-hospital setting, intravenous injection is not practical, particularly for mass casualties, and intramuscular injection would be preferred. The purpose of this study is to determine whether sodium nitrite and sodium thiosulfate are effective cyanide antidotes when administered by intramuscular injection. METHODS: We used a randomized, nonblinded, parallel-group study design in 3 mammalian models: cyanide gas inhalation in mice, with treatment postexposure; intravenous sodium cyanide infusion in rabbits, with severe hypotension as the trigger for treatment; and intravenous potassium cyanide infusion in pigs, with apnea as the trigger for treatment. The drugs were administered by intramuscular injection, and all 3 models were lethal in the absence of therapy. RESULTS: We found that sodium nitrite and sodium thiosulfate individually rescued 100% of the mice, and that the combination of the 2 drugs rescued 73% of the rabbits and 80% of the pigs. In all 3 species, survival in treated animals was significantly better than in control animals (log rank test, P<.05). In the pigs, the drugs attenuated an increase in the plasma lactate concentration within 5 minutes postantidote injection (difference: plasma lactate, saline solution-treated versus nitrite- or thiosulfate-treated 1.76 [95% confidence interval 1.25 to 2.27]). CONCLUSION: We conclude that sodium nitrite and sodium thiosulfate administered by intramuscular injection are effective against severe cyanide poisoning in 3 clinically relevant animal models of out-of-hospital emergency care.


Subject(s)
Antidotes/administration & dosage , Antidotes/therapeutic use , Cyanides/poisoning , Sodium Nitrite/administration & dosage , Sodium Nitrite/therapeutic use , Thiosulfates/administration & dosage , Thiosulfates/therapeutic use , Animals , Antidotes/pharmacology , Disease Models, Animal , Injections, Intramuscular , Male , Mice , Rabbits , Random Allocation , Sodium Nitrite/pharmacology , Sus scrofa , Thiosulfates/pharmacology
14.
Toxins (Basel) ; 8(9)2016 08 26.
Article in English | MEDLINE | ID: mdl-27571103

ABSTRACT

The research on natural snake venom metalloendopeptidase inhibitors (SVMPIs) began in the 18th century with the pioneering work of Fontana on the resistance that vipers exhibited to their own venom. During the past 40 years, SVMPIs have been isolated mainly from the sera of resistant animals, and characterized to different extents. They are acidic oligomeric glycoproteins that remain biologically active over a wide range of pH and temperature values. Based on primary structure determination, mammalian plasmatic SVMPIs are classified as members of the immunoglobulin (Ig) supergene protein family, while the one isolated from muscle belongs to the ficolin/opsonin P35 family. On the other hand, SVMPIs from snake plasma have been placed in the cystatin superfamily. These natural antitoxins constitute the first line of defense against snake venoms, inhibiting the catalytic activities of snake venom metalloendopeptidases through the establishment of high-affinity, non-covalent interactions. This review presents a historical account of the field of natural resistance, summarizing its main discoveries and current challenges, which are mostly related to the limitations that preclude three-dimensional structural determinations of these inhibitors using "gold-standard" methods; perspectives on how to circumvent such limitations are presented. Potential applications of these SVMPIs in medicine are also highlighted.


Subject(s)
Antidotes/therapeutic use , Metalloendopeptidases/antagonists & inhibitors , Protease Inhibitors/therapeutic use , Reptilian Proteins/antagonists & inhibitors , Snake Bites/drug therapy , Snake Venoms/antagonists & inhibitors , Animals , Antidotes/history , History, 18th Century , History, 19th Century , History, 20th Century , History, 21st Century , Humans , Metalloendopeptidases/chemistry , Metalloendopeptidases/history , Metalloendopeptidases/metabolism , Protease Inhibitors/history , Protein Conformation , Reptilian Proteins/chemistry , Reptilian Proteins/history , Reptilian Proteins/metabolism , Snake Bites/enzymology , Snake Bites/history , Snake Venoms/chemistry , Snake Venoms/enzymology , Snake Venoms/history , Structure-Activity Relationship
15.
Thyroid ; 26(10): 1488-1498, 2016 10.
Article in English | MEDLINE | ID: mdl-27461375

ABSTRACT

BACKGROUND: Iodine is essential for thyroid hormone synthesis and is an important regulator of thyroid function. Chronic iodine deficiency leads to hypothyroidism, but iodine excess also impairs thyroid function causing hyperthyroidism, hypothyroidism, and/or thyroiditis. This study aimed to investigate the underlying mechanisms by which exposure to chronic iodine excess impairs pituitary-thyroid axis function. METHODS: Male Wistar rats were treated for two months with NaI (0.05% and 0.005%) or NaI+NaClO4 (0.05%) dissolved in drinking water. Hormone levels, gene expression, and thyroid morphology were analyzed later. RESULTS: NaI-treated rats presented high levels of iodine in urine, increased serum thyrotropin levels, slightly decreased serum thyroxine/triiodothyronine levels, and a decreased expression of the sodium-iodide symporter, thyrotropin receptor, and thyroperoxidase mRNA and protein, suggesting a primary thyroid dysfunction. In contrast, thyroglobulin and pendrin mRNA and protein content were increased. Kidney and liver deiodinase type 1 mRNA expression was decreased in iodine-treated rats. Morphological studies showed larger thyroid follicles with higher amounts of colloid and increased amounts of connective tissue in the thyroid of iodine-treated animals. All these effects were prevented when perchlorate treatment was combined with iodine excess. CONCLUSIONS: The present data reinforce and add novel findings about the disruption of thyroid gland function and the compensatory action of increased thyrotropin levels in iodine-exposed animals. Moreover, they draw attention to the fact that iodine intake should be carefully monitored, since both deficient and excessive ingestion of this trace element may induce pituitary-thyroid axis dysfunction.


Subject(s)
Gene Expression Regulation/drug effects , Iodine/poisoning , Pituitary Gland/drug effects , Poisoning/physiopathology , Thyroid Gland/drug effects , Thyroiditis/etiology , Animals , Antidotes/therapeutic use , Iodide Peroxidase/antagonists & inhibitors , Iodide Peroxidase/genetics , Iodide Peroxidase/metabolism , Iodine/chemistry , Iodine/urine , Male , Perchlorates/therapeutic use , Pituitary Gland/metabolism , Pituitary Gland/pathology , Pituitary Gland/physiopathology , Poisoning/metabolism , Poisoning/pathology , Poisoning/prevention & control , RNA, Messenger/metabolism , Rats, Wistar , Receptors, Thyrotropin/antagonists & inhibitors , Receptors, Thyrotropin/genetics , Receptors, Thyrotropin/metabolism , Renal Elimination , Sodium Compounds/therapeutic use , Sodium Iodide/administration & dosage , Symporters/antagonists & inhibitors , Symporters/genetics , Symporters/metabolism , Thyroid Gland/metabolism , Thyroid Gland/pathology , Thyroid Gland/physiopathology , Thyrotropin/blood , Thyrotropin/metabolism , Thyroxine/blood , Thyroxine/metabolism , Toxicity Tests, Chronic , Toxicokinetics , Triiodothyronine/blood , Triiodothyronine/metabolism
16.
Toxins (Basel) ; 7(5): 1532-43, 2015 Apr 30.
Article in English | MEDLINE | ID: mdl-25941768

ABSTRACT

Renealmia alpinia (Rottb.) MAAS, obtained by micropropagation (in vitro) and wild forms have previously been shown to inhibit some toxic activities of Bothrops asper snake venom if preincubated before injection. In this study, assays were performed in a murine model in which extracts were administered for three days before venom injection. R. alpinia extracts inhibited lethal activity of B. asper venom injected by intraperitoneal route. Median Effective Dose (ED50) values were 36.6 ± 3.2 mg/kg and 31.7 ± 5.4 mg/kg (p > 0.05) for R. alpinia wild and in vitro extracts, respectively. At a dose of 75 mg/kg, both extracts totally inhibited the lethal activity of the venom. Moreover, this dose prolonged survival time of mice receiving a lethal dose of venom by the intravenous route. At 75 mg/kg, both extracts of R. alpinia reduced the extent of venom-induced pulmonary hemorrhage by 48.0% (in vitro extract) and 34.7% (wild extract), in agreement with histological observations of lung tissue. R. alpinia extracts also inhibited hemorrhage in heart and kidneys, as evidenced by a decrease in mg of hemoglobin/g of organ. These results suggest the possibility of using R. alpinia as a prophylactic agent in snakebite, a hypothesis that needs to be further explored.


Subject(s)
Antidotes/therapeutic use , Bothrops , Crotalid Venoms/toxicity , Hemorrhage/drug therapy , Plant Extracts/therapeutic use , Zingiberaceae , Animals , Kidney/drug effects , Kidney/pathology , Lung/drug effects , Lung/pathology , Mice , Myocardium/pathology , Phytotherapy , Snake Bites/drug therapy
17.
J Ethnopharmacol ; 153(3): 890-5, 2014 May 14.
Article in English | MEDLINE | ID: mdl-24704487

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: Envenoming caused by scorpion sting is a serious public health problem. In Brazil, 13,038 accidents caused by venomous animals have been reported. Of this total, 53% of the cases and 14 deaths were caused by scorpions. Furthermore, Tityus serrulatus (Buthidae) is the most dangerous scorpion due to the high toxicity of its venom. The treatment is the common supportive therapy and the serum therapy, but some people do not have access to both therapies and seek healing through the use of medical plants. AIM OF THE STUDY: This study evaluated the ability of the crude extract and fractions from the leaves of Ipomoea asarifolia in neutralizing the main biological effects caused by Tityus serrulatus envenoming in mice. MATERIALS AND METHODS: BALB/c mice were pretreated (i.v.) with 100 µλ of aqueous extracts and fractions dichloromethane, ethyl acetate, and n-butanol (CH2Cl2, EtOAc, and n-BuOH, respectively) of Ipomoea asarifolia, rutin or saline. Then, the animals received 100 µλ (i.p.) of venom of Tityus serrulatus (0.8 mg/kg). After six hours, the peritoneal lavage was performed with PBS and the number cells were determined using a Neubauer chamber. The supernatants were collected for determination of cytokines, such as IL-6, IL-12, and IL-1ß. RESULTS: The aqueous extract, fractions and rutin, at all doses, significantly reduced cell migration, which was endorsed by the reduction of the levels of certain cytokines. CONCLUSION: This is the first study that demonstrated the potential effect of Ipomoea asarifolia against inflammation caused by Tityus serrulatus venom, suggesting that these extracts and/or their bioactive molecules, especially the flavonoid rutin, have potential use in the therapy of this envenomation.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Antidotes/therapeutic use , Ipomoea , Plant Extracts/therapeutic use , Rutin/therapeutic use , Scorpion Venoms/toxicity , 3T3 Cells , Animals , Anti-Inflammatory Agents/pharmacology , Antidotes/pharmacology , Cell Movement/drug effects , Female , Male , Mice , Mice, Inbred BALB C , Phytotherapy , Plant Extracts/pharmacology , Plant Leaves , Rutin/pharmacology , Scorpions
18.
Bull Hist Med ; 86(2): 153-77, 2012.
Article in English | MEDLINE | ID: mdl-23000835

ABSTRACT

This article examines an international controversy over the most visible scientific event of Brazilian physiology in the nineteenth century. In 1881, Brazilian scientist João Baptista Lacerda stated that he had found an efficient antidote to the poison of Brazilian snakes: permanganate of potash (nowadays, potassium permanganate). His findings were given great publicity in Brazil and traveled rapidly around the world. Scientists, especially in France, contradicted Lacerda's claims. They argued that permanganate of potash could not be a genuine antidote to snake bites since it could not neutralize snake venom when diffused in the body. Lacerda turned down such criticism, claiming that clinical observation provided solid evidence for the drug's local action, on the spot surrounding the bite. The controversy over the use of permanganate of potash as an antidote to snake bite illustrates different regimes of proof that could be mobilized in favor of a physiological discovery.


Subject(s)
Antivenins/pharmacology , Crotalid Venoms/antagonists & inhibitors , Physiology/history , Potassium Permanganate/pharmacology , Snake Bites/therapy , Viperidae/physiology , Animals , Antidotes/pharmacology , Antidotes/therapeutic use , Antivenins/therapeutic use , Brazil , Dissent and Disputes , History, 19th Century , Potassium Permanganate/therapeutic use , Snake Bites/physiopathology
19.
Bul. Hist. Med ; 86(2): 153-177, 2012.
Article in English | HISA - History of Health | ID: his-28329

ABSTRACT

This article examines an international controversy over the most visible scientific event of Brazilian physiology in the nineteenth century. In 1881, Brazilian scientist João Baptista Lacerda stated that he had found an efficient antidote to the poison of Brazilian snakes: permanganate of potash (nowadays, potassium permanganate). His findings were given great publicity in Brazil and traveled rapidly around the world. Scientists, especially in France, contradicted Lacerda's claims. They argued that permanganate of potash could not be a genuine antidote to snake bites since it could not neutralize snake venom when diffused in the body. Lacerda turned down such criticism, claiming that clinical observation provided solid evidence for the drug's local action, on the spot surrounding the bite. The controversy over the use of permanganate of potash as an antidote to snake bite illustrates different regimes of proof that could be mobilized in favor of a physiological discovery. (AU)


Subject(s)
History, 19th Century , Physiology/history , Poisoning , Snake Bites/history , Potassium Permanganate/pharmacology , Potassium Permanganate/therapeutic use , Antivenins/pharmacology , Antivenins/therapeutic use , Antidotes/pharmacology , Antidotes/therapeutic use , Brazil
20.
Ginecol Obstet Mex ; 79(1): 38-44, 2011 Jan.
Article in Spanish | MEDLINE | ID: mdl-21966782

ABSTRACT

We report the case of a 16 years old female patient, with a pregnancy history of 11.4 weeks by ultrasound and intrauterine fetal death. In a private clinic were prescribed methotrexate 500 mg intramuscular single dose, and vaginal misoprostol. She had a clinical feature of five days of evolution characterized by fever of 39 degrees C, nausea, general attack and vomiting. The initial diagnosis was severe sepsis secondary to septic abortion, oral candidiasis and acute poisoning by methotrexate. After that, she was referred to the Instituto Nacional de Perinatologia, where stayed with fever for four days, and was managed with hydration, antibiotics, folinic acid and alkalizing. Her recovery was gradual. She was discharged after 12 days with significant clinical improvement. The literature review describes that the use of methotrexate for abortion purpose with therapeutic-dose presents a similar adverse effects to those found in our patient, however there are no case reports that describe the use of this drug in macrodosis for the same purpose, and their cytotoxic effects. We present this case because the patient used a macrodosis of this antimetabolite and due to the premature and empirical management with folinic acid, joined with alkalinization of urine, is the ideal treatment and as it is illustrated in our case.


Subject(s)
Abortifacient Agents/poisoning , Abortion, Induced/adverse effects , Abortion, Missed/therapy , Methotrexate/poisoning , Abortifacient Agents/administration & dosage , Abortion, Septic/diagnosis , Abortion, Septic/drug therapy , Administration, Intravaginal , Adolescent , Anti-Bacterial Agents/therapeutic use , Antidotes/therapeutic use , Candidiasis, Oral/complications , Female , Filgrastim , Granulocyte Colony-Stimulating Factor/therapeutic use , Humans , Injections, Intramuscular , Leucovorin/therapeutic use , Misoprostol/administration & dosage , Neutropenia/chemically induced , Neutropenia/drug therapy , Poisoning/drug therapy , Pregnancy , Recombinant Proteins , Vomiting/chemically induced
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