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1.
Clinics ; 70(1): 24-29, 1/2015. graf
Artigo em Inglês | LILACS | ID: lil-735868

RESUMO

OBJECTIVES: To investigate an unusual outbreak of tetrodotoxin poisoning in Leizhou, southeast China, a case series analysis was conducted to identify the source of illness. METHODS: A total of 22 individuals experienced symptoms of poisoning, including tongue numbness, dizziness, nausea and limb numbness and weakness. Two toxic species, Amoya caninus and Yongeichthys nebulosus, were morphologically identified from the batches of gobies consumed by the patients. Tetrodotoxin levels in the blood and Goby fish samples were detected using liquid chromatography-tandem mass spectrometry. RESULTS: The tetrodotoxin levels in the remaining cooked Goby fish were determined to be 2090.12 µg/kg. For Amoya caninus, the toxicity levels were 1858.29 µg/kg in the muscle and 1997.19 µg/kg in the viscera and for Yongeichthys nebulosus, they were 2783.00 µg/kg in the muscle and 2966.21 µg/kg in the viscera. CONCLUSION: This outbreak demonstrates an underestimation of the risk of Goby fish poisoning. Furthermore, the relationships among the toxic species, climates and marine algae present should be clarified in the future. .


Assuntos
Adulto , Idoso , Animais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peixes Venenosos , Doenças Transmitidas por Alimentos/etiologia , Perciformes , Tetrodotoxina/envenenamento , Cromatografia Líquida , China/epidemiologia , Surtos de Doenças , Doenças Transmitidas por Alimentos/epidemiologia , Estudos Retrospectivos , Espectrometria de Massas em Tandem , Tetrodotoxina/sangue
2.
Braz. j. med. biol. res ; 47(12): 1068-1074, 12/2014. graf
Artigo em Inglês | LILACS | ID: lil-727656

RESUMO

Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.


Assuntos
Animais , Masculino , Jejuno/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Miosinas/metabolismo , Taurina/farmacologia , Antagonistas Adrenérgicos alfa/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Atropina/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Cimetidina/farmacologia , Difenidramina/farmacologia , Sistema Nervoso Entérico/efeitos dos fármacos , Antagonistas dos Receptores Histamínicos H1/farmacologia , /farmacologia , Jejuno/fisiologia , Antagonistas Muscarínicos/farmacologia , Quinase de Cadeia Leve de Miosina/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico/metabolismo , Fosforilação , Fentolamina/farmacologia , Propranolol/farmacologia , Ratos Sprague-Dawley , Taurina/antagonistas & inibidores , Tetrodotoxina/farmacologia , Verapamil/farmacologia
3.
J. venom. anim. toxins incl. trop. dis ; 20: 1-2, 04/02/2014. ilus
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1484606

RESUMO

In this brief communication the authors report eleven cases of human poisoning caused by ingestion of pufferfish meat. Three patients (two children and one adult) were seriously affected. The circumstances that precipitated the poisoning are discussed as well as the clinical aspects observed. No deaths were registered and the patients did not present sequelae after the episode.


Assuntos
Humanos , Animais , Doenças Transmitidas por Alimentos , Tetraodontiformes , Tetrodotoxina/envenenamento , Venenos de Peixe , Brasil
4.
Rev. Soc. Bras. Med. Trop ; 43(1): 92-94, Jan.-Feb. 2010. ilus
Artigo em Português | LILACS | ID: lil-540521

RESUMO

É descrito um envenenamento pela ingestão de vísceras de um baiacu-pintado (Sphoeroides testudineus) por uma criança de dois anos, que apresentou sudorese fria, fraqueza muscular progressiva, parada cardiorrespiratória e morte. São discutidos os riscos do consumo da carne e vísceras de baiacus, fato comum em certas regiões do Brasil.


A case of poisoning resulting from ingestion of viscera from a spotted puffer fish (Sphoeroides testudineus) by a two-year-old child is described. The child presented cold sweating, progressive muscle weakness, cardiorespiratory arrest and death. The risks of consuming the meat and viscera of puffer fish, which is a common occurrence in certain regions of Brazil, are discussed.


Assuntos
Animais , Humanos , Lactente , Masculino , Doenças Transmitidas por Alimentos , Tetraodontiformes , Tetrodotoxina/envenenamento , Evolução Fatal
5.
J. venom. anim. toxins incl. trop. dis ; 16(3): 421-431, 2010. ilus, graf, tab
Artigo em Inglês | LILACS, VETINDEX | ID: lil-557170

RESUMO

Specimens of the pufferfish Arothron hispidus collected at Parangipettai, on the southeast coast of India, were subjected to bacterial isolation and identification. Three species were identified, namely Bacillus sp., Kytococcus sedentarius and Cellulomonas fimi. Partially-purified microbial filtrates exhibited hemolytic activity on chicken and human erythrocytes of O, B and AB blood groups, with maximum activity of 32 HU. The microbial filtrates also presented ATPase, Mg2+-ATPase, Na+K+-ATPase and AchE enzymatic activities of positive neuromodulation in Kytococcus sedentarius with 1300, 300.1, 1549.98 and 140.55%, in Cellulomonas fimi with 620, 300, 10 and 128.42%, and in Bacillus species with 40, 200, 849.98 and 158.69%, respectively. Toxicity symptoms were observed when the bacterial filtrate was intraperitoneally injected into mice. The bacterial filtrate caused adverse effects on viability of the mouse muscle cell line (L929) and leukemia cell line (P388). Maximum level of inhibition was observed on the growth of L929 cell line. Bacillus lentimorbus inhibited the cell line from 84.03 to 94.43% whereas Bacillus species inhibited the growth in a range between 77.25 and 86.16% at the lowest dilution.Specimens of the pufferfish Arothron hispidus collected at Parangipettai, on the southeast coast of India, were subjected to bacterial isolation and identification. Three species were identified, namely Bacillus sp., Kytococcus sedentarius and Cellulomonas fimi. Partially-purified microbial filtrates exhibited hemolytic activity on chicken and human erythrocytes of O, B and AB blood groups, with maximum activity of 32 HU. The microbial filtrates also presented ATPase, Mg2+-ATPase, Na+K+-ATPase and AchE enzymatic activities of positive neuromodulation in Kytococcus sedentarius with 1300, 300.1, 1549.98 and 140.55 percent, in Cellulomonas fimi with 620, 300, 10 and 128.42 percent, and in Bacillus species with 40, 200, 849.98 and 158.69 percent, respectively. Toxicity symptoms were observed when the bacterial filtrate was intraperitoneally injected into mice. The bacterial filtrate caused adverse effects on viability of the mouse muscle cell line (L929) and leukemia cell line (P388). Maximum level of inhibition was observed on the growth of L929 cell line. Bacillus lentimorbus inhibited the cell line from 84.03 to 94.43 percent whereas Bacillus species inhibited the growth in a range between 77.25 and 86.16 percent at the lowest dilution.(AU)


Assuntos
Tetrodotoxina/farmacologia , Bactérias , Linhagem Celular , Células Musculares , Tetraodontiformes
7.
Diagn. tratamento ; 9(4): 183-185, out.-dez. 2004. ilus
Artigo em Português | LILACS | ID: lil-550898

RESUMO

A ingestão de algumas espécies de baiacus pode causar graves envenenamentos por tetrodo-toxina, uma potente neurotoxina presente na pele, ovários, fígado e intestinos desses peixes. A tetrodotoxina bloqueia canais de sódio na junção neuromuscular, causando impossibilidade de condução do impulso nervoso para os músculos, sendo considerada uma das mais potentes toxinas encontradas na natureza.Vários animais apresentam tetrodotoxina e derivados em órgãos e tecidos para sua defesa. A toxina parece ser apenas armazenada, sendo produzida por bactérias.Intoxicações por tetrodotoxina causam paralisia muscular progressiva que atinge sua máxima intensidade em cerca de 24 horas. O grande risco é a morte por insu?ciência respiratória.Não existe tratamento especí?co para a intoxicação por tetrodotoxina; a lavagem gástrica é importante nas primeiras seis horas do quadro e, em fases posteriores, o recurso de?nitivo é a assistência ventilatória mecânica, mas o índice de óbito é alto mesmo assim.


Assuntos
Tetrodotoxina
8.
Mem. Inst. Oswaldo Cruz ; 99(2): 141-145, Mar. 2004. tab
Artigo em Inglês | LILACS | ID: lil-360966

RESUMO

The effects of mucosally added Escherichia coli heat stable enterotoxin (STa 30 ng ml-1) on the basal short-circuit current (Isc in µA cm-2) across stripped and unstripped sheets of jejuna and ilea taken from fed, starved (4 days, water ad lib) and undernourished (50 percent control food intake for 21 days) gerbil (Gerbillus cheesmani) were investigated. The effect of neurotoxin tetrodotoxin (TTX 10 µM) and the effects of replacing chloride by gluconate or the effects of removing bicarbonate from bathing buffers on the maximum increase in Isc induced by STa were also investigated. The maximum increase in Isc which resulted from the addition of STa were significantly higher in jejuna and ilea taken from starved and undernourished gerbils when compared with the fed control both using stripped and unstripped sheets. In the two regions of the small intestine taken from fed and starved animals TTX reduced the maximum increase in Isc induced by STa across unstripped sheets only. Moreover in jejuna and ilea taken from undernourished gerbils TTX reduced significantly the maximum increase in Isc induced by STa across stripped and unstripped sheets. Replacing chloride by gluconate decreased the maximum increase in Isc induced by STa across jejuna and ilea taken from undernourished gerbils only. Removing bicarbonates from bathing buffer decreased the maximum increase in Isc across the jejuna and ilea taken from starved and undernourished gerbils.


Assuntos
Animais , Feminino , Masculino , Anestésicos Locais , Cloretos , Íleo , Jejuno , Tetrodotoxina , Condutividade Elétrica , Gerbillinae , Potenciais da Membrana
9.
Biol. Res ; 32(1): 29-33, 1999. tab, graf
Artigo em Inglês | LILACS | ID: lil-241340

RESUMO

The underlying mechanisms of acetycholine-induced intestinal relaxation in the lizard Liolaemus tenuis tenuis are still unknows. By using a classical model of intestinal recording of isometric contraction and relaxation in conjunction with specific pharmacological tools, this article studies the possible influence of EDRF/NO and nicotinic ganglionar receptors on the Ach-induced relaxation in an effort to elucidate the probable mechanisms involved in ACh effect. It was observed that the relaxation of the lizard intestine elicited by ACh (10(-7) - 4 x 10(-4) M) was not affected by hexametonium (5 x 10(4) M) or tetrodotoxin (10(-6) M). Nicotine (10(-7) to 10(-4) M) induced relaxation was significantly antagonized by hexametonium; however, it was not influenced by tetrodotoxin. These results allow us to discard a neuronal pathway in cholinergic-induced relaxation, suggesting a more direct cholinergic effect on the smooth muscle, perhaps mediated by an unknown substance released by some specialized tissue. N-nitro-L-arginine, used to block NO-synthase and NO production, induced no changes in ACh-induced relaxation. Methylene blue, a soluble guanylate cyclase inhibitor, induced no changes in ACh-induced relaxation. These results allow us to dicard a probable role of EDRF/nitric oxide in the ACh-induced relaxation of lizard small intestine, providing evidence that this mechanism could be different from reported on other species.


Assuntos
Animais , Masculino , Feminino , Agonistas Colinérgicos/farmacologia , Esôfago/efeitos dos fármacos , Intestino Delgado/efeitos dos fármacos , Relaxamento Muscular/efeitos dos fármacos , Tono Muscular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Hexametônio/farmacologia , Lagartos , Azul de Metileno/farmacologia , Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Antagonistas Nicotínicos/farmacologia , Óxido Nítrico Sintase , Nitroarginina/farmacologia , Tetrodotoxina/farmacologia
10.
Braz. j. med. biol. res ; 30(6): 793-9, jun. 1997. ilus, graf
Artigo em Inglês | LILACS | ID: lil-194182

RESUMO

The presence of inhibitory nonadrenergic noncholinergic (NANC) intrinsic innervation of the circular muscle of the gastrointestinal sphincters of the South American (SA) opossum was investigated in vitro. Isolated circular muscle strips from the esophagogastric and ileocolonic junctions but not from the gastroduodenal (pylorus) region developed spontaneous tension. Tetrodotoxin (TTX, 1 muM) augmented the spontaneous tension only in the ileocolonic junction strips. Electrical field stimulation of esophagogastric and ileocolonic junction strips caused frequency-dependent responses consisting of a relaxation at lower frequencies (<1 Hz) and a biphasic response or contraction at higher frequencies. In the strips from the pyloric region electrical field stimulation abolished the spontaneous activity at lower frequencies and induced contractions at higher frequencies. The responses elicited by electrical field stimulation in the three sphincters were abolished by TTX (1 muM). Electrical field-induced contractions were reduced while relaxations were enhanced by atropine (1 muM). In the presence of atropine (1 muM) and guanethidine (3 muM), electrical field stimulation, nicotine and ATP induced frequency-or concentration-dependent relaxations of the three sphincters that were abolished by TTX (1 muM). Isoproterenol and sodium nitroprusside caused concentration-dependent relaxations which were TTX-resistant. These findings indicate that the sphincteric circular muscle of the SA opossum gastrointestinal tract is relaxed by the activation of intrinsic NANC nerves and therefore can be used as a model for the study of the mechanisms involved in these responses.


Assuntos
Animais , Feminino , Atropina/farmacologia , Estimulação Elétrica , Junção Esofagogástrica/efeitos dos fármacos , Guanetidina/farmacologia , Técnicas In Vitro , Isoproterenol/farmacologia , Relaxamento Muscular/efeitos dos fármacos , Gambás/fisiologia , Piloro/efeitos dos fármacos , Tetrodotoxina/farmacologia , América do Sul
11.
Acta gastroenterol. latinoam ; 27(1): 19-25, mar. 1997. tab, graf, ilus
Artigo em Inglês | LILACS | ID: lil-196659

RESUMO

Background/Aim: Short-circuit current (Isc) and transepithelial potential difference (PD) of rat distal colon decrease during acute hypoxia and overshoot on reoxygenation. It is not known whether tonic intrinsic nervous activity may influence these responses. Methods: Preparations lacking the submucosal plexus (isolet mucosa) and preparations retaining it (mucosa-submucosa) were mounted in Ussing chambers at 37 degrees Celsius and gassed with 95 percent O2 -5 percent CO2; Isc and PD were monitored. A 5-min hypoxia with 95 percent N2-5 percent CO2 was followed by reoxygenation. The procedure was repeated in the presence of the nervous blocking agent, tetrodotoxin (10(-6)M) in the serosal side of the chamber. Results: In the isolated mucosa (n=10) hypoxia reduced Isc by -55 + 5 percent and PD by -54 + 6 percent below baseline; reoxygenatory overschoots were, respectively, + 60 + 17 percent and + 16 percent. Tetrodotoxin slightly and transiently reduced baseline Isc (-16 + 2 percent) and PD (-14 + 3 percent), with a small resistivity increase. It did not significatively modify the responses to responses to either hypoxia or reoxygenation. In mucosa-submucosa preparations (n=9) hypoxia reduced Isc (-54 + 8 percent) and PD (-61 + 4 percent). On reoxygenation Isc and PD were increased, respectively, +30 + 5 percent and +19 + 6 percent over baseline. Tetrodotoxin reduced baseline Isc (-59,6 + 5 percent) and PD (61,3 + 6 percent). It enhanced hypoxic Isc and PD decreases (-80 + 5 percent), but not the reoxygenatory overschoots. Conclusions: 1) Tetrodotoxin affects baseline Isc and PD more intensely in submucosal plexus innervated preparations than in the isolated mucosa. 2) The epithelial electrical response to acute hypoxia appears to be modulated by tonic neural activity.


Assuntos
Ratos , Animais , Masculino , Colo/inervação , Hipóxia/metabolismo , Plexo Submucoso/metabolismo , Tetrodotoxina/farmacologia , Doença Aguda , Colo/efeitos dos fármacos , Colo/metabolismo , Eletrofisiologia , Epitélio/inervação , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/inervação , Mucosa Intestinal/metabolismo , Ratos Wistar
12.
Rev. ciênc. saúde ; 15(1/2): 253-63, jan.-dez. 1996. tab, graf
Artigo em Português | LILACS | ID: lil-249054

RESUMO

Os peixes considerados venenosos ou sarcotóxicos possuem toxinas na pele, músculos, víceras e gônodas. Dentre as 80 espécies existentes no Brasil, em Santa Catarina destaca-se o baiacu, cuja toxina (tetrodotoxina) apresenta propriedades neurotôxicas. Os acidentes causados pela ingestão de baiacu tem sido descrita ocasionalmente no estado de Santa Catarina....


Assuntos
Humanos , Feminino , Criança , Peixes Venenosos/microbiologia , Tetrodotoxina/envenenamento , Epidemiologia/classificação
13.
J. venom. anim. toxins ; 2(1): 28-38, 1996. tab, ilus
Artigo em Inglês | LILACS | ID: lil-194269

RESUMO

We have already shown the presence of guanidine neurotoxins in calcareous red algae and mussels collected in the Säo Sebastiäo channel State of Säo Paulo,Brazil). It is known that these neurotoxins comprise more than 25 analogues such as tetrodotoxin (TTX) and derivatives plus the paralytic shellfish toxins (PST) found in a variety of marine, freshwater and amphibious species. Filter feeding animals generally possess large amounts of these neurotoxins. The tunicates are sessil marine animals with a high rate of sea water filtration. The tunics and siphons of 50 specimens of Phallusia nigra were dissected and the visceral organs were immersed in methanol containing acetic acid 0.02 N ph 5.0. The extract was prepared by homogenization, filtration and the methanolic phase was concentrated under reduced pressure and defatted with chloroform. The polar phase was evaporated and the residue dissolved in deionized water for further purification in ionic-exchange resin column (Bio-Gel P-2) and HPLC analysis. The extract showed paralytic effects on mouse assay (26.9 MU/100mg) and on crustacean isolated nerve preparations. The chemical analysis for TTX and PST revealed toxins with retention times similar to gonyautoxins, saxitoxins and TTX. These findings are important to explain future toxin envenoming outbreaks on the Brazilian coast.


Assuntos
Animais , Água do Mar/química , Braquiúros/efeitos dos fármacos , Dinoflagelados/patogenicidade , Moluscos , Neurotoxinas/envenenamento , Paralisia , Saxitoxina/farmacologia , Tetrodotoxina/farmacologia , Urocordados/patogenicidade , Microbiologia da Água
15.
Braz. j. med. biol. res ; 25(4): 379-83, 1992. ilus
Artigo em Inglês | LILACS | ID: lil-109043

RESUMO

GABA is a major inhibitory neurotransmitter in the central nervous system, including the retina. In the present paper we present evidence for the existence of two independent mechanisms for GABA release in cultured retina cells. Eight-day-old chick embryo retinas were dissociated and plated in 35-mm plastic dishes and cultured for 3 or 7 days at 37 grade C. An increase of 3 to 5-fold in GABA release was observed in cultures of 3 or 7 days in vitro preloaded with 0.5 uCi[3H} GABA and stimulated with glutamate (100 uM) or veratridine (100 uM). Tetrodotoxin (1 uM) blocked the release induced by veratridine but not by glutamate. In contrast, the non-N-methyl-D-aspartate (NMDA)glutamate antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 100 uM) was able to inhibit GABA release promoted by glutamate but not by veratridine. These results indicate that depolarization of retinal cells byopening of voltage-dependent sodium channels or activation of non-NMDA glutamate receptors can trigger intracellular events that lead to calcium-independent GABA release


Assuntos
Embrião de Galinha , Células Cultivadas , Ácido gama-Aminobutírico/induzido quimicamente , Glutamatos , Retina/citologia , Tetrodotoxina , Veratridina/administração & dosagem
17.
Bol. Asoc. Méd. P. R ; 77(11): 482-5, nov. 1985. tab
Artigo em Inglês | LILACS | ID: lil-29276

RESUMO

La tetrodotoxina es una neurotoxina extremadamente potente encontrada en los peces tamborín (puffer) y algunos otros animales. Actúa por medio de un bloqueo selectivo de los canales de sodio en las membranas de nervio y músculo, causando un parálisis rápidamente progresiva y muerte por fallo respiratorio. Presentamos un caso de intoxicación por pez tamborín en Puerto Rico, seguido de una revisión de la literatura


Assuntos
Adolescente , Humanos , Masculino , Peixes Venenosos , Tetrodotoxina/envenenamento , Porto Rico
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