Amount Of Toxin Research Articles

Accumulation and effects of cyanobacterial microcystins and anatoxin-a on benthic larvae of Chironomus spp. (Diptera: Chironomidae)

Larvae of Chironomidae are distributed world-wide and are very abundant in eutrophic water bodies affected by cyanobacterial blooms. However, there is little information on the effect of cyanobacteria and their metabolites on these aquatic organisms. Our studies revealed that benthic species of Chironomus inhabiting a hypertrophic lake where blooms of microcystin (MC) and/or anatoxin-a (ANTX)-producing filamentous Planktothrix agardhii, Dolichospermum spp. and Cuspidothrix issatschenkoi occur, fed on these cyanobacteria and accumulated cyanotoxins. Up to 3.2 µg MCs g-1 F.W. and up to 185 µg ANTX g-1 F.W. were detected. Of the four MC variants detected in the cyanobacterial biomass [Asp3, Dhb7]MC-RR and MC-LR prevailed, whereas in the larvae it was [Asp3, Dhb7]MC-RR and MC-LA. The effect of pure MC-LR and ANTX as well as crude extracts of MC-producing P. agardhii and ANTX-producing D. lemmermannii on lake and riverine larvae of Chironomus spp. was also compared. The assays revealed that pure cyanotoxins (concentrations: 0.83-3.32 mg L-1) were generally less toxic to riverine larvae than cyanobacterial extracts containing approximately 10-times less toxins. The survival of both the lake and riverine Chironomus larvae did not decrease when exposed to environmentally relevant concentrations of cyanotoxins (< 0.20 mg L-1). The larvae were also highly resistant to higher amounts (up to 0.35 mg ANTX L-1 and 0.42 mg MCs L-1) of extracellular toxins. In the natural environment, Chironomus larvae exposed to toxins contained in cyanobacterial prey, dissolved in water and/or bound to bottom sediments may be very important vectors of cyanotoxins to higher levels in aquatic food chains. To the best of our knowledge, this is the first report on the accumulation of ANTX and effects of cyanotoxins on Chironomus larvae.

Accumulation of tetrodotoxin from diet in two species of scavenging marine snails

A feeding experiment of TTX-containing diet was conducted using the small scavenging marine snails Pliarcularia globosa and Reticunassa festiva. Seventy-five specimens of each species were divided into 15 groups of 5 individuals, of which 3 groups were directly submitted, without feeding, to toxin quantification as described below. TTX was not detected. Each of the remaining 12 groups was accommodated in a plastic case (80×70×40 mm) filled with seawater, and fed for 24 hours with ovary tissue (0.1 g) of the pufferfish Takifugu vermicularis, whose TTX content had previously been determined. Then the seawater was exchanged for fresh seawater, the snails were reared for 4 days without feeding, and then the seawater was changed again. This feeding/rearing cycle (5 days) was repeated 8 times, and 3 groups were sampled every 2 cycles. The combined viscera and combined muscle of each group were each extracted with 0.1% aqueous acetic acid, and then TTX was quantified by liquid chromatography-mass spectrometry. The estimated amount of ingested TTX was calculated by multiplying the difference between the amounts of ovary tissue supplied and remaining by the toxin content (122-126 MU/g). Similar mean values of 5.1 MU/group/cycle in P. globosa and 5.3 MU/group/cycle in R. festiva were obtained. Toxin content (TTX amount per gram of tissue) and toxin amount (TTX amount per group) during the experimental period were 0.23-2.85 MU/g and 0.05-0.96 MU/group, respectively, in P. globosa viscera. Both values increased markedly from the 2nd cycle to the 6th cycle. In contrast, no such increase in toxin content/amount was observed throughout the experimental period in P. globosa muscle (<0.05-0.86 MU/g, <0.02-0.27 MU/group), R. festiva viscera (<0.05-0.8 MU/g, <0.02-0.33 MU/group), and R. festiva muscle (<0.05-0.81 MU/g, <0.02-0.23 MU/group). The remaining ratio of TTX (percentage of total toxin amount [sum of the toxin amount of viscera and muscle] to estimated TTX ingestion amount) was less than 4% in P. globosa, and less than 2% in R. festiva after the 4th cycle, suggesting that the possibility that these two species would accumulate TTX at levels high enough to raise food hygiene issues is low.

Presencia de Fusarium graminearum en muestras de trigo destinado al consumo humano

One of the most important diseases in cereal crops is Fusarium head blight, being Fusarium graminearum the main etiological agent. This fungus has the ability to produce a wide spectrum and quantity of toxins, especially deoxynivalenol (DON). During the last crop season (2012–2013) the climatic conditions favored Fusarium colonization. The objective of this work was to determine the presence of this fungus as well as the DON content in 50 wheat grain samples. Our results showed that 80% of the samples were contaminated with Fusarium graminearum. Twenty four percent (24%) of the samples contained ≥ 1μg/g DON, 26% ranged from 0,5 and 0,99μg/g, and the remaining 50% had values lower than 0,5μg/g. Correlation was found between the presence of Fusarium graminearum and DON. It is necessary to establish DON limit values in wheat grains for human consumption.

The Effects of Botulinium Toxin in Vocal Nodules

Background and ObjectivesZZVocal nodules are the most common voice disorder due to vocal misuses. Vocal nodules are primarily treated with voice therapy and are rarely removed through laryngomicrosurgery. Although the rate of recovery for individual patients may vary, 60-70% of them are fully treated. Because vocal nodules have many possible causes, 30-40% of patients remain untreated. Also, vocal nodules recurrence after the surgical treatment is sometimes observed. The author claims that incomplete contact between vocal cords during phonation is a major cause of the vocal nodules. Most vocal nodules do occur from incomplete contact between vocal cords during phonation, and various voice therapies are designed to improve habitual misuses of the vocal cords. However, vocal nodules tend to remain unhealed unless patients change their habitual misuses of the vocal cords. The cricothyroid muscle tension is known to hinder the contact between vocal cords. The author injected a restricted amount of botulinium toxin to the cricothyroid muscle to reduce the muscle tension and observed changes in vocal cords’ movement. Subjects and MethodZZIn this study, the author injected botulinium toxin to the cricothyroid muscle of 21 patients. For 2-4 weeks, we observed patients’ responses to the treatment, by measuring changes in subglottal pressure, mean air flow rate, maximum phonation time, jitter, shimmer, noise-to-harmonic ration of patients and subjective evaluation of voice changes. In addition, the author conducted stroboscopy to evaluate the usefulness of the treatment. ResultsZZThe improvement was in the subjective evaluation of voice changes and stroboscopic findings. ConclusionZZThe observation demonstrated a great improvement in vocal nodules after the injection of botulinium toxin into the cricothyroid muscle.

Electronic cigarette: A review

The principal addictive component of tobacco smoke is nicotine. The mechanisms of nicotine addiction are highly complex and are responsible for maintenance of smoking behaviour. Use of electronic cigarettes (E-cigarettes), devices that deliver a nicotine containing vapor has increased rapidly across the world. They are marketed as a healthier alternatives to conventional cigarettes. There is extensive debate over long-term safety and efficacy of these devices on public health. Studies show that the vapor generated from the E-cigarettes has a variable amount of nicotine and potential harmful toxins. Until robust research demonstrates the safety of E-cigarettes and efficacy in the treatment of tobacco dependence, their role as safe smoking cessation tool is unclear. This review highlights the recent data regarding E-cigarettes toxicity, impact on lung function, and efficacy in smoking reduction and cessation.

Intradetrusor Injections of Onabotulinum Toxin-A in Children With Urinary Incontinence due to Neurogenic Detrusor Overactivity Refractory to Antimuscarinic Treatment.

PurposeThis was a prospective single-arm study to assess the efficacy and safety of intradetrusor injections of onabotulinum toxin-A in children with urinary incontinence associated with neurogenic detrusor overactivity due to myelomeningocele. All patients had failed the first-line treatment of a combination of oral antimuscarinics and intermittent catheterization.Materials and MethodsThe study group consisted of 31 children with myelomeningocele with a mean age of 7.95 years (range, 5-3 years) who were followed up for a mean of 29 weeks. The amount of onabotulinum toxin A injected was 10 U/kg with a maximal dose of 300 U. There were 20 to 30 injection sites with rigid cystoscopic guidance under general anesthesia.ResultsThirty of 31 patients reported dryness between intermittent catheterization intervals. The mean reduction in maximum detrusor pressure and the mean increase in maximum cystometric capacity from baseline were 53% and 51.5%, respectively, 6 weeks after injection. We found a 324% increase in mean bladder compliance and a 57% increase in mean intermittent catheterization volumes. The mean duration of efficacy was 28 weeks with a single injection and 36 weeks for repeated injections (minimum, 16 weeks; maximum, 52 weeks). The mean time interval between repeated onabotulinum toxin-A injections was 7 months (maximum, 13 months). Intradetrusor injections of onabotulinum toxin-A were well tolerated.ConclusionsOnabotulinum toxin-A injections into the bladder wall provide a significant symptomatic and urodynamic improvement in children with neurogenic detrusor overactivity due to myelomeningocele who are on intermittent catheterization. The treatment seems to be safe and very well tolerated.

Area and Depth Investigation of Anzali Pond Using Satellite Imageries and Group Method of Data Handling Neural Network

Analysis of changes in natural resources is one of the fundamental issues in remote sensing. Several research studies regarding the process of changes in natural resources using satellite imageries and image processing techniques have been done. Anzali pond is one of the important ecosystems in Iran that under the impact of some factors such as drought has the gradual drying trend over the last years. This study measures the area of basin surface and predicts the process of changes in the climate of the pond neighborhood during the next years, using GMDH neural network. Satellite imagery and meteorological data is used for this analysis. The final results represent reduction in area from 82 km^2 in 1998 to 51 km^2 in 2010. The average depth of the pond decreased to less than 4m in 2010 from 9m in 1998. The main reason for this reduction is diversion of rivers, sediment entering and changes in land use around the pond. If this trend continues, the amount of pollutants and toxins will reach to warning and this is a serious threat for animals and pond dwellers.

Utility of Upper Gastrointestinal Endoscopy for Management of Patients with Roundup® Poisoning

Introduction: Roundup® is a herbicide widely used in Japan in gardening and agriculture. When ingested, Roundup is highly toxic, but gastrointestinal decontamination, including gastric lavage, is not routinely performed after ingestion. Endoscopy may be useful in managing individuals with liquid herbicide poisoning, by identifying gastric residual contents, assessing mucosal damage and retrieving herbicide directly by aspiration. Case report: A 73 year old, 40 kg female with a history of depression was transported to our emergency room by ambulance 1 h after attempting suicide by ingesting 100 ml Roundup, which contains 48% glyphosate-potassium, and 52% surfactant and water. This volume was below a fatal dose (<5000 mg/kg), but may have caused organ dysfunction and mucosal damage. After confirming respiratory and circulatory stability and after obtaining informed consent from the patient, endoscopy (XQ 260; Olympus, Tokyo, Japan) was performed in the emergency room to retrieve residual herbicide. About 80 ml of herbicide in the stomach were aspirated endoscopically with only mild erosion observed in the mucosa of the stomach. The patient was able to resume oral intake 2 days after endoscopy and was discharged without any complications on day 5. Conclusion: Endoscopy may be useful in cases of liquid poisoning including, Roundup, both to determine the amount of residual toxin and to remove it from the stomach.

The Crystal Structure of Shiga Toxin Type 2 with Bound Disaccharide Guides the Design of a Heterobifunctional Toxin Inhibitor

Shiga toxin type 2 (Stx2a) is clinically most closely associated with enterohemorrhagic E. coli O157:H7-mediated hemorrhagic colitis that sometimes progresses to hemolytic-uremic syndrome. The ability to express the toxin has been acquired by other Escherichia coli strains, and outbreaks of food poisoning have caused significant mortality rates as, for example, in the 2011 outbreak in northern Germany. Stx2a, an AB5 toxin, gains entry into human cells via the glycosphingolipid receptor Gb3. We have determined the first crystal structure of a disaccharide analog of Gb3 bound to the B5 pentamer of Stx2a holotoxin. In this Gb3 analog,-GalNAc replaces the terminal-Gal residue. This co-crystal structure confirms previous inferences that two of the primary binding sites identified in theB5 pentamer of Stx1 are also functional in Stx2a. This knowledge provides a rationale for the synthesis and evaluation of heterobifunctional antagonists for E. coli toxins that target Stx2a. Incorporation of GalNAc Gb3 trisaccharide in a heterobifunctional ligand with an attached pyruvate acetal, a ligand for human amyloid P component, and conjugation to poly[acrylamide-co-(3-azidopropylmethacrylamide)] produced a polymer that neutralized Stx2a in a mouse model of Shigatoxemia.

Harmful Algae Records in Venice Lagoon and in Po River Delta (Northern Adriatic Sea, Italy)

A detailed review of harmful algal blooms (HAB) in northern Adriatic Sea lagoons (Po River Delta and Venice lagoon) is presented to provide “updated reference conditions” for future research and monitoring activities. In the study areas, the high mollusc production requires the necessity to identify better methods able to prevent risks for human health and socioeconomical interests. So, an integrated approach for the identification and quantification of algal toxins is presented by combining microscopy techniques with Liquid Chromatography coupled with High Resolution Time of Flight Mass Spectrometry (HPLC-HR-TOF-MS). The method efficiency was first tested on some samples from the mentioned coastal areas, where Dinophysis spp. occurred during summer in the sites directly affected by seawaters. Although cell abundance was always <200 cells/L, the presence of Pectenotoxin-2 (PTX2), detected by HPLC-HR-TOF-MS, indicated the potential release of detectable amounts of toxins even at low cell abundance.

Alternative method to detect compounds produced by Gambierdiscus spp.

Event Abstract Back to Event Alternative method to detect compounds produced by Gambierdiscus spp. Jon A. Sánchez1, Marta Leirós1, Eva Alonso1, Carmen Alfonso1, Amparo Alfonso1* and Luis M. Botana1* 1 University of Santiago de Compostela, Faculty of Veterinary Lugo, Spain Ciguatoxins (CTXs) and CTX precursors are produced by several Gambierdiscus spp. These polyether toxins are associated to ciguatera fish poisoning (CFP). In addition to CTX, maitotoxins (MTX) and gambierol are also produced by these dinoflagellates. MTX mechanism of action is strictly Ca2+ dependent, since the toxin induces a massive cytoplasmatic Ca2+ entrance. However, CTX activates the voltage-dependent sodium channels and no relation with calcium fluxes has been showed. The aim of this work was to study the effect of both toxins in the cytoplasmic calcium levels in the SH-SY5Y neuroblastoma cell line by using the fluorescent probe Fura-2 AM. Two completely different calcium profiles were obtained. While, MTX induces a sustained dose-dependent increase in Fura-2 ratio, CTX produces a light increase in dye ratio. From MTX results a calibration curve concentration versus Fura-2 ratio was obtained where the toxin concentration of an unknown sample can be calculated. Then, the effect of four samples from Gambierdiscus cultures was studied and different calcium profiles were obtained. A high increase in Fura-2 ratio was observed in two samples. The calcium profile was similar to MTX and by using the calibration curve the amount of toxin was calculated (4.9 and 1.8 nM of MTX). In the other samples, from the Fura-2 results the presence of CTX like compounds can be established. Keywords: maitotoxin, Ciguatoxins, Fura-2 AM, Ciguatera Poisoning, Calcium, Gambierdiscus spp. Conference: IMMR | International Meeting on Marine Research 2014, Peniche, Portugal, 10 Jul - 11 Jul, 2014. Presentation Type: Poster Presentation Topic: SEAFOOD TECHNOLOGY Citation: Sánchez JA, Leirós M, Alonso E, Alfonso C, Alfonso A and Botana LM (2014). Alternative method to detect compounds produced by Gambierdiscus spp.. Front. Mar. Sci. Conference Abstract: IMMR | International Meeting on Marine Research 2014. doi: 10.3389/conf.fmars.2014.02.00178 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 12 May 2014; Published Online: 18 Jul 2014. * Correspondence: Prof. Amparo Alfonso, University of Santiago de Compostela, Faculty of Veterinary Lugo, Lugo, Lugo, 27002, Spain, amparo.alfonso@usc.es Prof. Luis M Botana, University of Santiago de Compostela, Faculty of Veterinary Lugo, Lugo, Lugo, 27002, Spain, Luis.Botana@usc.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jon A Sánchez Marta Leirós Eva Alonso Carmen Alfonso Amparo Alfonso Luis M Botana Google Jon A Sánchez Marta Leirós Eva Alonso Carmen Alfonso Amparo Alfonso Luis M Botana Google Scholar Jon A Sánchez Marta Leirós Eva Alonso Carmen Alfonso Amparo Alfonso Luis M Botana PubMed Jon A Sánchez Marta Leirós Eva Alonso Carmen Alfonso Amparo Alfonso Luis M Botana Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

An international collaborative study of the effect of active pertussis toxin on the modified Kendrick test for acellular pertussis vaccines

Speculation that the Japanese modified intra-cerebral challenge assay, which is used in several countries for control of acellular pertussis vaccines, depends on the presence of small amounts of active pertussis toxin led to an assumption that it may not be appropriate for highly toxoided or genetically detoxified vaccines. Consequently, at the recommendation of a World Health Organisation AD Hoc Working Group on mouse protection models for testing and control of acellular pertussis vaccine, the effect of pertussis toxin on the modified intra-cerebral challenge assay (modified Kendrick, MICA) was evaluated in an international collaborative study. Results of this study showed that for genetically detoxified vaccines both with and without active pertussis toxin the MICA clearly distinguished mice vaccinated with acellular vaccines from unvaccinated mice and gave a significant dose–response relationship. However, vaccine samples containing active pertussis toxin (5 or 50 ng/single human dose) appeared to be more potent than the equivalent sample without active pertussis toxin. Similar results were also given by two respiratory infection models (intranasal and aerosol) included in the study. The results also indicated that the effect of pertussis toxin may vary depending on mouse strain.

Plasmon-Enhanced Fluorescence Biosensors: a Review.

Surfaces of metallic films and metallic nanoparticles can strongly confine electromagnetic field through its coupling to propagating or localized surface plasmons. This interaction is associated with large enhancement of the field intensity and local optical density of states which provides means to increase excitation rate, raise quantum yield, and control far field angular distribution of fluorescence light emitted by organic dyes and quantum dots. Such emitters are commonly used as labels in assays for detection of chemical and biological species. Their interaction with surface plasmons allows amplifying fluorescence signal (brightness) that accompanies molecular binding events by several orders of magnitude. In conjunction with interfacial architectures for the specific capture of target analyte on a metallic surface, plasmon-enhanced fluorescence (PEF) that is also referred to as metal-enhanced fluorescence (MEF) represents an attractive method for shortening detection times and increasing sensitivity of various fluorescence-based analytical technologies. This review provides an introduction to fundamentals of PEF, illustrates current developments in design of metallic nanostructures for efficient fluorescence signal amplification that utilizes propagating and localized surface plasmons, and summarizes current implementations to biosensors for detection of trace amounts of biomarkers, toxins, and pathogens that are relevant to medical diagnostics and food control.

Seasonal characteristics and tetrodotoxin-producing ability of bacteria in gastropod Oliva hirasei

Tetrodotoxin (TTX) is a well-known marine toxin, which is widely distributed in marine animals and originates from marine bacteria. To compare seasonal characteristics of aerobic bacteria in the toxic gastropod Oliva hirasei, the muscle and digestive gland of O. hirasei were collected from New Taipei City, and plated on ORI agar for aerobic plate count. Bacterial counts of the digestive gland were 7.10 and 8.89 log (CFU/g) from O. hirasei in August 2011 and March 2012, respectively, and those of the muscle were 6.84 and 8.20 log (CFU/g) in August 2011 and March 2012, respectively. The total bacterial counts in the March samples were higher than those in the August samples, but the amount of toxin showed an inverted pattern. The predominant genera from the muscle and digestive gland of O. hirasei were Vibrio, Pseudomonas, Shewanell, Pasteurella, Aeromonas, and others. Virio was 43 and 46% of the genera in August from the muscle and the digestive gland of O. hirasei and 70 and 82% in March. In addition, to detect the TTX-producing ability of isolated bacteria, the bacterial strains were cultured, extracted, and analyzed by HPLC and LC–MS/MS. The results showed that Vibrio, Pseudomonas, and Shewanella certainly produced TTX.

Characteristics of a Microcystin-LR Biodegrading Bacterial Isolate: Ochrobactrum sp. FDT5

Mass growth of blue-green algae in eutrophic water bodies leads to a large amount of toxins, e.g. microcystins (MCs). How to remove MCs from water bodies is an environmental problem. In this study, an algicidal bacterium Ochrobactrum sp. FDT5 was isolated and found to have microcystin-LR (MC-LR) degradation capacity, which could be enhanced by a domestication process. The FDT5 cell density, MC-LR initial concentration, temperature, and pH on the degradation of MC-LR were investigated. The results indicated that the initial cell density of FDT5 and the initial concentration of MC-LR could influence MC-LR degradation. The optimum conditions were under the temperature of 35°C with pH of 7.0. After FDT5 was exposed to MC-LR for 2 days, FDT5 cells produced active cellular components that degraded MC-LR. These cellular components were heat-inactivated and removed when FDT5 cells were removed by filtration.

Regulation of toxin production in the pathogenic clostridia

The genus Clostridium comprises a large, heterogeneous group of obligate anaerobic, Gram-positive spore forming bacilli. Members of this genus are ubiquitous in the environment and although most species are considered saprophytic, several are pathogenic to both humans and animals. These bacteria cause a variety of diseases including neuroparalysis, gas gangrene, necrotic enteritis, food poisoning, toxic shock syndrome and pseudomembraneous colitis, which in most cases arise as a consequence of the production of potent exotoxins. Treatment options are often limited, underscoring the need for new treatment strategies and novel therapeutics. Understanding the fundamental mechanisms and signals that control toxin production in the pathogenic clostridia may lead to the identification of novel therapeutic targets that can be exploited in the development of new antimicrobial agents.

Detection of venom–antivenom (VAV) immunocomplexes in vitro as a measure of antivenom efficacy

The measurement of free venom with enzyme immunoassay in serum of patients with snake envenoming is used to confirm snake identification and to determine if sufficient antivenom has been given. Recent studies with Russell's viper (RV; Daboia russelii) envenoming have detected free venom post-antivenom despite recovery of coagulopathy. This raises the question as to whether this assay also measures venom–antivenom (VAV) complexes. In this study we developed an assay to measure VAV complexes and investigate the binding of venom and antivenom in vitro. The assay consisted of rabbit anti-snake venom IgG attached to a microplate which binds the venom component of VAV and anti-horse IgG antibodies conjugated to horseradish peroxidase to detect the antivenom portion of VAV. A known amount of venom or toxin was incubated with increasing antivenom concentrations and VAV was detected as absorbance at 450 nm and plotted against AV concentration. Pseudonaja textilis (brown snake), Notechis scutatus (tiger snake), Oxyuranus scutellatus (taipan), Tropidechis carinatus (rough-scaled snake), Pseudechis porphyriacus (red-bellied black snake) and D. russelii mixtures with appropriate antivenoms were assayed. Measured VAV initially increased with increasing antivenom concentration until it reached a maximum after which the VAV concentration decreased with further increasing antivenom concentrations. The VAV curves for two Australian snake venom–antivenom mixtures, Hoplocephalus stephensii and Ancanthophis antarcticus, had broad VAV peaks with two maxima. Two fractions isolated from N. scutatus venom and Russell's viper factor X activator toxin produced similar VAV curves to their whole venoms. The antivenom concentration for which the maximum VAV occurred was linearly related to the venom concentration, and this slope or ratio was consistent with that used to define the neutralisation units for Australian antivenoms. The maximal VAV point appears to represent the antivenom concentration where every venom molecule (toxin) is attached to at least one antivenom molecule (antibody) on average and may be a useful measure of antivenom efficacy. In vivo this would mean that for a defined antivenom concentration, venom components will be eliminated and are trapped in the central compartment.

Acute liver failure caused by mushroom poisoning: a case report and review of the literature

It is estimated that there are over 5,000 species of mushrooms worldwide. Some of them are edible and some are poisonous due to containing significant toxins. In more than 95% of mushroom toxicity cases, poisoning occurs as a result of misidentification of the mushroom by an amateur mushroom hunter. The severity of mushroom poisoning may vary, depending on the geographic location where the mushroom is grown, growth conditions, the amount of toxin delivered, and the genetic characteristics of the mushroom. Amanita phalloides is the most common and fatal cause of mushroom poisoning. This mushroom contains amanitins, which are powerful hepatotoxins that inhibit RNA polymerase II in liver. Mushroom poisoning is a relatively rare cause of acute liver failure. A 63-year-old male patient was admitted to the emergency room with weakness, nausea, vomiting, and diarrhea. He reported ingesting several wild mushrooms about 36 hours earlier. In this article we report a case of lethal Amanita phalloides intoxication from stored mushrooms.

Targeted disruption of layer 4 during development increases GABAAreceptor neurotransmission in the neocortex

Cortical dysplasia (CD) associates with clinical pathologies, including epilepsy and mental retardation. CD results from impaired migration of immature neurons to their cortical targets, leading to clustering of neural cells and changes in cortical properties. We developed a CD model by administering methylazoxymethanol (MAM), an anti-mitotic, to pregnant ferrets on embryonic day 33; this leads to reduction in cortical thickness in addition to redistribution and increased expression of GABAA receptors (GABAAR). We evaluated the impact of MAM treatment on GABAAR-mediated synaptic transmission in postnatal day 0-1 neurons, leaving the ganglionic eminence (GE) and in layer 2/3 pyramidal cells of postnatal day 28-38 ferrets. Embryonic day 33 MAM treatment significantly increases the amplitude and frequency of spontaneous GABAAR-mediated inhibitory postsynaptic currents (IPSCs) in the cells leaving the GE. In older MAM-treated animals, the amplitude and frequency of GABAAR-mediated spontaneous IPSCs in layer 2/3 pyramidal cells is increased, as are the amplitude and frequency of miniature IPSCs. The kinetics of GABAAR opening also altered following treatment with MAM. Western blot analysis shows that the expression of the GABAAα3R and GABAAγ2R subunits amplified in our model animals. We did not observe any significant change in the passive properties of either the layer 2/3 pyramidal cells or cells leaving the GE after MAM treatment. These observations reinforce the idea that synaptic neurotransmission through GABAAR enhances following treatment with MAM and coincides with our finding of increased GABAAαR expression within the upper cortical layers. Overall, we demonstrate that small amounts of toxins delivered during corticogenesis can result in long-lasting changes in ambient expression of GABAAR that influence intrinsic neuronal properties.

High Risk of Embryo-Fetal Toxicity: Placental Transfer of T-2 Toxin and Its Major Metabolite HT-2 Toxin in BeWo Cells

Though T-2 toxin is the most harmful mycotoxin to the fetuses, it remains unclear whether T-2 toxin and its major metabolite, HT-2 toxin, could pass the placenta into the fetus and which kind of placental transport is involved in the passage. To illustrate their placenta transfer mechanism, the uptake and efflux of T-2 and HT-2 toxins across apical membranes of placenta with BeWo cells as a model were studied at different temperatures, pHs, and in the presence of transporter inhibitors with a developed liquid chromatography-tandem mass spectrometry to determine the amount of toxins in both fetal and maternal sites. Higher unidirectional transport of T-2 toxin was observed in the apical-to-basolateral direction than basolateral-to-apical one, whereas HT-2 toxin exhibited similar transport rate from the 2 directions. The main ATP-binding cassette transporters had no effect on the efflux of 2 toxins. Initial uptake of T-2 toxin was sodium dependent and saturable, and the apical uptake was temperature dependent and enhanced under acidic condition. The apical uptake of T-2 toxin was inhibited by metabolic inhibitors and the organic anion and organic cation transporter inhibitors. These results suggested that an active transport mechanism was responsible for the uptake of T-2 toxin, whereas passive diffusion was the principal mechanism for HT-2 toxin transport in the placenta. Taken together, these data characterized the placental transfer of T-2 and HT-2 toxins. The present study offered new ways of reducing the risks of T-2 and HT-2 toxins to both mother and fetuses.