Suchergebnisse

α-Amanitin is a natural bicyclic octapeptide, from the family of amatoxins, present in the deadly mushroom species Amanita phalloides. The toxicological and clinical interests raised by this toxin, require highly sensitive, accurate and reproducible quantification methods for pharmacokinetic studies. In the present work, a high-performance liquid chromatographic (HPLC) method with in-line connected diode-array (DAD) and electrochemical (EC) detection was developed and validated to quantify α-amanitin in biological samples (namely liver and kidney). Sample pre-treatment consisted of a simple and unique deproteinization step with 5% perchloric acid followed by centrifuga tion at 16,000. ×g, 4. °C, for 20. min. The high recovery found for α-amanitin (≥96.8%) makes this procedure suitable for extracting α-amanitin from liver and kidney homogenates. The resulting supernatant was collected and injected into the HPLC. Mobile phase was composed by 20% methanol in 50. mM citric acid, and 0.46. mM octanessulfonic acid, adjusted to pH 5.5. The chromatographic runs took less than 22. min and no significant endogenous interferences were observed at the α-amanitin retention time. Calibration curves were linear with regression coefficients higher than 0.994. The overall inter- and intra-assay precision did not exceed 15.3%.The present method has low interferences with simple and fast processing steps, being a suitable procedure to support in vivo toxicokinetic studies involving α-amanitin. In fact, the validated method was successfully applied to quantify α-amanitin in biological samples following intraperitoneal α-amanitin administration to rats. Moreover, human plasma was also used as matrix and the purposed method was adequate for detection of α-amanitin in that matrix. The results clearly indicate that the proposed method is suitable to investigate the pharmacokinetic and tissue distribution of α-amanitin. Additionally, the method will be very useful in the development of novel and potent antidotes against amatoxins poisoning and to improve the knowledge of α-amanitin toxicity. ; This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project Pest- C/EQB/LA0006/2013. Juliana Garcia and Vera Marisa Costa thank FCT - Foundation for Science and Technology - for their PhD grant (SFRH/BD/74979/ 2010 ) and Post-doc grant (SFRH/BPD/63746/2009), respectively. ; info:eu-repo/semantics/publishedVersion

Amanita phalloides, also known as 'death cap', is one of the most poisonous mushrooms, being involved in the majority of human fatal cases of mushroom poisoning worldwide. This species contains three main groups of toxins: amatoxins, phallotoxins, and virotoxins. From these, amatoxins, especially α-amanitin, are the main responsible for the toxic effects in humans. It is recognized that α-amanitin inhibits RNA polymerase II, causing protein deficit and ultimately cell death, although other mechanisms are thought to be involved. The liver is the main target organ of toxicity, but other organs are also affected, especially the kidneys. Intoxication symptoms usually appear after a latent period and may include gastrointestinal disorders followed by jaundice, seizures, and coma, culminating in death. Therapy consists in supportive measures, gastric decontamination, drug therapy and, ultimately, liver transplantation if clinical condition worsens. The discovery of an effective antidote is still a major unsolved issue. The present paper examines the clinical toxicology of A. phalloides, providing the currently available information on the mechanisms of toxicityinvolved and on the current knowledge on the treatment prescribed against this type of mushrooms. Antidotal perspectives will be raised as to set the pace to new and improved therapy against these mushrooms. ; This work was supported by the Fundação para a Ciência e Tecnologia (FCT ) – project PTDC/DTPFTO/4973/2014 – and the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project Pest-C/EQB/LA0006/2013. Juliana Garcia and Vera Marisa Costa thank FCT for their PhD grant (SFRH/BD/74979/2010) and Post-doc grants (SFRH/BPD/63746/2009 and SFRH/BPD/110001/2015), respectively. ; info:eu-repo/semantics/publishedVersion

Mushroom poisonings occur when ingestion of wild mushrooms containing toxins takes place, placing the consumers at life-threatening risk. In the present case report, an unusual multiple poisoning with isoxazoles- and amatoxins-containing mushrooms in a context of altered mental state and poorly controlled hypertension is presented. A 68-year-old female was presented to São João hospital (Portugal) with complaints of extreme dizziness, hallucinations, vertigo and imbalance, 3 h after consuming a stew of wild mushrooms. The first observations revealed altered mental state and elevated blood pressure. The examination of cooked mushroom fragments allowed a preliminary identification of Amanita pantherina. Gas chromatography-mass spectrometry (GC-MS) showed the presence of muscimol in urine. Moreover, through high-performance liquid chromatography-ultraviolet detection (HPLC-UV) analysis of the gastric juice, the presence of α-amanitin was found, showing that amatoxins-containing mushrooms were also included in the stew. After 4 days of supportive treatment, activated charcoal, silybin and N-acetylcysteine, the patient recovered being discharged 10 days post-ingestion with no organ complications. The prompt and appropriate therapy protocol for life-threatening amatoxins toxicity probably saved the patient's life as oral absorption was decreased and also supportive care was immediately started. ; This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project Pest-C/EQB/LA0006/2013. Juliana Garcia and Vera Marisa Costa thank FCT e Foundation for Science and Technology e for their PhD grant (SFRH/BD/74979/2010) and Post-doc grant (SFRH/BPD/63746/2009), respectively. ; info:eu-repo/semantics/publishedVersion

Amanita phalloides is responsible for more than 90 % of mushroom-related fatalities, and no effective antidote is available. α-Amanitin, the main toxin of A. phalloides, inhibits RNA polymerase II (RNAP II), causing hepatic and kidney failure. In silico studies included docking and molecular dynamics simulation coupled to molecular mechanics with generalized Born and surface area method energy decomposition on RNAP II. They were performed with a clinical drug that shares chemical similarities to α-amanitin, polymyxin B. The results show that polymyxin B potentially binds to RNAP II in the same interface of α-amanitin, preventing the toxin from binding to RNAP II. In vivo, the inhibition of the mRNA transcripts elicited by α-amanitin was efficiently reverted by polymyxin B in the kidneys. Moreover, polymyxin B significantly decreased the hepatic and renal α-amanitin-induced injury as seen by the histology and hepatic aminotransferases plasma data. In the survival assay, all animals exposed to α-amanitin died within 5 days, whereas 50 % survived up to 30 days when polymyxin B was administered 4, 8, and 12 h post-α-amanitin. Moreover, a single dose of polymyxin B administered concomitantly with α-amanitin was able to guarantee 100 % survival. Polymyxin B protects RNAP II from inactivation leading to an effective prevention of organ damage and increasing survival in α-amanitin-treated animals. The present use of clinically relevant concentrations of an already human-use-approved drug prompts the use of polymyxin B as an antidote for A. phalloides poisoning in humans. ; Juliana Garcia, Vera Marisa Costa, Ricardo Dinis-Oliveira and Ricardo Silvestre thank FCT—Foundation for Science and Technology—for their PhD grant (SFRH/ BD/74979/2010), Post-doc grants (SFRH/BPD/63746/2009 and SFRH/BPD/110001/2015) and Investigator grants (IF/01147/2013) and (IF/00021/2014), respectively. This work was supported by the Fundação para a Ciência e Tecnologia (FCT) – project PTDC/DTPFTO/ 4973/2014 – and the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project Pest-C/EQB/LA0006/2013. ; info:eu-repo/semantics/publishedVersion

Amanita phalloides is responsible for more than 90 % of mushroom-related fatalities, and no effective antidote is available. a-Amanitin, the main toxin of A. phalloides, inhibits RNA polymerase II (RNAP II), causing hepatic and kidney failure. In silico studies included docking and molecular dynamics simulation coupled to molecular mechanics with generalized Born and surface area method energy decomposition on RNAP II. They were performed with a clinical drug that shares chemical similarities to a-amanitin, polymyxin B. The results show that polymyxin B potentially binds to RNAP II in the same interface of a-amanitin, preventing the toxin from binding to RNAP II. In vivo, the inhibition of the mRNA transcripts elicited by a-amanitin was efficiently reverted by polymyxin B in the kidneys. Moreover, polymyxin B significantly decreased the hepatic and renal a-amanitin-induced injury as seen by the histology and hepatic aminotransferases plasma data. In the survival assay, all animals exposed to a-amanitin died within 5 days, whereas 50 % survived up to 30 days when polymyxin B was administered 4, 8, and 12 h post-a-amanitin. Moreover, a single dose of polymyxin B administered concomitantly with a-amanitin was able to guarantee 100 % survival. Polymyxin B protects RNAP II from inactivation leading to an effective prevention of organ damage and increasing survival in a-amanitin-treated animals. The present use of clinically relevant concentrations of an already human-use-approved drug prompts the use of polymyxin B as an antidote for A. phalloides poisoning in humans. ; Juliana Garcia, Vera Marisa Costa, Ricardo Dinis-Oliveira and Ricardo Silvestre thank FCT-Foundation for Science and Technology-for their PhD grant (SFRH/BD/74979/2010), Post-doc grants (SFRH/BPD/63746/2009 and SFRH/BPD/110001/2015) and Investigator grants (IF/01147/2013) and (IF/00021/2014), respectively. This work was supported by the Fundacao para a Ciencia e Tecnologia (FCT) - project PTDC/DTPFTO/4973/2014 - and the European Union (FEDER funds ...

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 3‐phytase FLF1000 as a feed additive for pigs for fattening and minor porcine species for growing. This additive contains 3‐phytase produced by a genetically modified strain of Komagataella phaffii and it is authorised in the European Union as a feed additive for feed for chickens for fattening, laying hens, chickens reared for laying and for minor poultry species for fattening or reared for laying or for breeding. The applicant requested the extension of use of the additive to pigs for fattening and minor porcine species for growing. The FEEDAP Panel concluded that the use of the product as a feed additive for pigs raises no concerns for the consumer safety nor for the environment. The additive should be regarded as a potential respiratory sensitiser. The applicant provided a combined tolerance and efficacy trial in weaned piglets to support the safety for the target species. However, owing to the lack of precise data on the total feed intake of the animals, the FEEDAP Panel did not consider further the study for the assessment and consequently no conclusion could be drawn regarding the safety of the additive for pigs for fattening nor for other minor growing porcine species. Three studies were considered for the efficacy and from the data obtained the FEEDAP Panel concluded that the additive has the potential to be efficacious in improving the phosphorus utilisation in pigs for fattening at a minimum level of 500 FTU/kg feed.

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of Belfeed B MP/ML as a feed additive for sows in order to have benefits in piglets and for all porcine species. This additive contains endo‐1,4‐β‐xylanase produced by a genetically modified strain of Bacillus subtilis and it is authorised in the European Union as a feed additive for poultry for fattening, weaned piglets and pigs for fattening. The applicant requested the extension of use of the additive to sows in order to have benefits in piglets and to all porcine species at any developmental stage at 10 IU/kg feed. The FEEDAP Panel concluded that there are no concerns for consumer safety and no risks for the environment are expected from the use of Belfeed B MP/ML in all Suidae species. The additive is not irritant for skin or eye but it should be considered a potential respiratory sensitiser for the users, the Panel could not conclude on the potential of the additive as a potential dermal sensitiser. Considering the results from a tolerance trial done in weaned piglets, those in a subchronic oral toxicity study and the nature/origin of the product under assessment the Panel concluded that the additive is safe for all porcine species at any developmental stage. The data previously assessed in piglets and pigs for fattening allowed to conclude that the additive is efficacious at 10 IU/kg feed in suckling piglets and all Suidae species from suckling to slaughter. The data submitted to support the efficacy for sows was considered insufficient and therefore the Panel could not conclude on the efficacy in sows.