T. Cleveland, Jiujiang Yu†, D. Bhatnagar, Zhi-Yuan Chen, Robert L. Brown, P. Chang, J. Cary
Understanding the complex interrelationships of plant and fungal gene products during the host plant—Aspergillus flavus interaction is key in developing strategies to interrupt the aflatoxin contamination process. Fungal processes necessary for invasion of the plant and production of aflatoxin can be broken down into three categories: 1) cell wall degradation (cellulases, pectinases, amylases, and proteinases), 2) fungal development (cell wall synthesis and conidiophore and conidial formation), and 3) aflatoxin biosynthesis and regulation. Fungal expressed sequence tag (EST) projects have led to a rapid expansion in the number of candidate genes governing the processes involved in invasion of the plant and aflatoxin contamination. Plant factors have been discovered through the use of proteomics and natural product chemistry that may influence fungal processes involved in invasion and aflatoxin contamination. These factors can also be divided into three categories: 1) seed proteins/inhibitors of fungal cell wall degrading enzymes, 2) seed/kernel natural products that may influence fungal growth and/or aflatoxin synthesis, and 3) plant stress‐responsive proteins. If the interaction between the plant and the fungus can be better understood through use of proteomics, genomics, and natural product chemistry, particularly in how plant factors may influence fungal processes contributing to virulence and aflatoxin contamination, this information could accelerate development of breeding through marker selection and/or gene insertion technologies for enhancing host plant resistance.
{"title":"Progress in Elucidating the Molecular Basis of the Host Plant—AspergillusFlavus Interaction, a Basis for Devising Strategies to Reduce Aflatoxin Contamination in Crops","authors":"T. Cleveland, Jiujiang Yu†, D. Bhatnagar, Zhi-Yuan Chen, Robert L. Brown, P. Chang, J. Cary","doi":"10.1081/TXR-200027892","DOIUrl":"https://doi.org/10.1081/TXR-200027892","url":null,"abstract":"Understanding the complex interrelationships of plant and fungal gene products during the host plant—Aspergillus flavus interaction is key in developing strategies to interrupt the aflatoxin contamination process. Fungal processes necessary for invasion of the plant and production of aflatoxin can be broken down into three categories: 1) cell wall degradation (cellulases, pectinases, amylases, and proteinases), 2) fungal development (cell wall synthesis and conidiophore and conidial formation), and 3) aflatoxin biosynthesis and regulation. Fungal expressed sequence tag (EST) projects have led to a rapid expansion in the number of candidate genes governing the processes involved in invasion of the plant and aflatoxin contamination. Plant factors have been discovered through the use of proteomics and natural product chemistry that may influence fungal processes involved in invasion and aflatoxin contamination. These factors can also be divided into three categories: 1) seed proteins/inhibitors of fungal cell wall degrading enzymes, 2) seed/kernel natural products that may influence fungal growth and/or aflatoxin synthesis, and 3) plant stress‐responsive proteins. If the interaction between the plant and the fungus can be better understood through use of proteomics, genomics, and natural product chemistry, particularly in how plant factors may influence fungal processes contributing to virulence and aflatoxin contamination, this information could accelerate development of breeding through marker selection and/or gene insertion technologies for enhancing host plant resistance.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76757659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Miyoshi, A. Morita, T. Teranishi, K. Tomochika, Shigeo Yamamoto, S. Shinoda
Vibrio vulnificus biotype 2, a primary eel pathogen, is also an opportunistic pathogen for humans. The strains in this biotype secrete a cytolysin into the culture medium. The cytolysin from the strain CDC B3547 (ATCC 33817), which was originally isolated from a human leg wound, can disrupt various kinds of eukaryotic cells including erythrocytes and mast cells, and artificial vesicles, liposomes. The cytolysin is a 50 kDa single‐chain protein and is categorized into the pore‐forming toxins. After binding tightly to the cell‐membrane cholesterol in a temperature‐independent manner, the toxin molecules assemble each other in a temperature‐dependent manner, forming a small transmembrane pore. When incubated with a metalloprotease from the same species, the cytolysin is converted to the nicked toxin composed of some peptide chains, joined with disulfide bond(s). This nicked toxin is more hydrophilic while maintaining comparable cytolytic activity.
{"title":"An Exocellular Cytolysin Produced by Vibrio vulnificus CDC B3547, a Clinical Isolate in Biotype 2 (Serovar E)","authors":"S. Miyoshi, A. Morita, T. Teranishi, K. Tomochika, Shigeo Yamamoto, S. Shinoda","doi":"10.1081/TXR-120030650","DOIUrl":"https://doi.org/10.1081/TXR-120030650","url":null,"abstract":"Vibrio vulnificus biotype 2, a primary eel pathogen, is also an opportunistic pathogen for humans. The strains in this biotype secrete a cytolysin into the culture medium. The cytolysin from the strain CDC B3547 (ATCC 33817), which was originally isolated from a human leg wound, can disrupt various kinds of eukaryotic cells including erythrocytes and mast cells, and artificial vesicles, liposomes. The cytolysin is a 50 kDa single‐chain protein and is categorized into the pore‐forming toxins. After binding tightly to the cell‐membrane cholesterol in a temperature‐independent manner, the toxin molecules assemble each other in a temperature‐dependent manner, forming a small transmembrane pore. When incubated with a metalloprotease from the same species, the cytolysin is converted to the nicked toxin composed of some peptide chains, joined with disulfide bond(s). This nicked toxin is more hydrophilic while maintaining comparable cytolytic activity.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87010377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The history of the development of analytical methods for detecting fungal toxins is rich and varied. Method development has followed a process somewhat akin to Darwinian evolution: methods are selected based upon the characteristics most desirable to the analyst. Typically, this has lead to the development of accurate and sensitive methods for their detection, with a recurring emphasis on improving the speed and lowering the costs of the assays. Like evolution, there have been radical developments, incremental developments, and techniques that have fallen from favor only to be rediscovered. This review focuses on recent developments in technologies for detection of mycotoxins, with a particular emphasis on the myriad forms of biosensors that have begun to appear. Specifically, recent development in evanescent wave technologies (surface plasmon resonance, fiber optic sensors), lateral flow and dipstick devices, fluorescence polarization and time‐resolved fluorescence, microbead assays, and capillary electrophoretic immunoassays, are described. The challenge for the emerging technologies is to demonstrate advantages over the more conventional, and better established, techniques in settings outside the analytical laboratory.
{"title":"Emerging Technologies for Mycotoxin Detection","authors":"C. Maragos","doi":"10.1081/TXR-200027859","DOIUrl":"https://doi.org/10.1081/TXR-200027859","url":null,"abstract":"The history of the development of analytical methods for detecting fungal toxins is rich and varied. Method development has followed a process somewhat akin to Darwinian evolution: methods are selected based upon the characteristics most desirable to the analyst. Typically, this has lead to the development of accurate and sensitive methods for their detection, with a recurring emphasis on improving the speed and lowering the costs of the assays. Like evolution, there have been radical developments, incremental developments, and techniques that have fallen from favor only to be rediscovered. This review focuses on recent developments in technologies for detection of mycotoxins, with a particular emphasis on the myriad forms of biosensors that have begun to appear. Specifically, recent development in evanescent wave technologies (surface plasmon resonance, fiber optic sensors), lateral flow and dipstick devices, fluorescence polarization and time‐resolved fluorescence, microbead assays, and capillary electrophoretic immunoassays, are described. The challenge for the emerging technologies is to demonstrate advantages over the more conventional, and better established, techniques in settings outside the analytical laboratory.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87553447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Yamamoto, Kazuhito Watanabe, T. Matsunaga, Toshiyuki Kimura, Tatsuya Funahashi, H. Yoshimura
Many oxidative metabolites of tetrahydrocannabinols (THCs), active components of Cannabis sativa L. (Cannabinaceae), were pharmacologically potent, and 11‐hydroxy‐THCs, 11‐oxo‐Δ8‐THC, 7‐oxo‐Δ8‐THC, 8β,9β‐epoxyhexahydrocannabinol (EHHC), 9α,10α‐EHHC and 3'‐hydroxy‐Δ9‐THC were more active than THC in pharmacological effects such as catalepsy, hypothermia and barbiturate synergism in mice, indicating that these metabolites are active metabolites of THCs. Cannabidiol (CBD), another major component, was biotransfomred to two novel metabolites, 6‐hydroxymethyl‐Δ9‐THC and 3‐pentyl‐6, 7, 7a, 8, 9, 11a‐hexahydro‐1, 7‐dihydroxy‐7,10‐dimethyldibenzo[b,d]oxepin (PHDO) through 8R,9‐epoxy‐CBD and 8S, 9‐epoxy‐CBD as intermediates, respectively, identified by us. Both metabolites have some pharmacological effects comparable to Δ9‐THC. Cannabinol (CBN), the other major component, was mainly metabolized to 11‐hydroxy‐CBN by hepatic microsomes of animals including humans. The pharmacological effects of the metabolite were higher than those of CBN demonstrating that 11‐hydroxylation of CBN is an activation pathway of the cannabinoid as is the case in THCs. Tolerance developed to catalepsy, hypothermia and pentobarbital‐induced sleep prolonging effects of Δ8‐THC and its active metabolite, 11‐hydroxy‐Δ8‐THC. Reciprocal cross‐tolerance also developed to pharmacological effects and the magnitude of tolerance development produced by the metabolite was significantly higher than that by Δ8‐THC indicating that 11‐hydroxy‐Δ8‐THC has important role not only in the pharmacological effects but also its tolerance development of Δ8‐THC. THCs and their metabolites competed with the specific binding of CP‐55,940, an agonist of cannabinoid receptor, to synaptic membrane from bovine cerebral cortex. The Ki value of THCs and their metabolites were closely parallel to their pharmacological effects in mice. A novel cytochrome P450 (cyp2c29) was purified and identified for the first time by us as a major enzyme responsible for the metabolic activation of Δ8‐THC at the 11‐position in the mouse liver. cDNA of cyp2c29 was cloned from a mouse cDNA library and its sequence was determined. All of major P450s involving the metabolic activation of Δ8‐THC at the 11‐position are belonging to CYP2C subfamily in mammalian liver.
{"title":"Pharmacology and Toxicology of Major Constituents of Marijuana—On the Metabolic Activation of Cannabinoids and Its Mechanism","authors":"I. Yamamoto, Kazuhito Watanabe, T. Matsunaga, Toshiyuki Kimura, Tatsuya Funahashi, H. Yoshimura","doi":"10.1081/TXR-120026915","DOIUrl":"https://doi.org/10.1081/TXR-120026915","url":null,"abstract":"Many oxidative metabolites of tetrahydrocannabinols (THCs), active components of Cannabis sativa L. (Cannabinaceae), were pharmacologically potent, and 11‐hydroxy‐THCs, 11‐oxo‐Δ8‐THC, 7‐oxo‐Δ8‐THC, 8β,9β‐epoxyhexahydrocannabinol (EHHC), 9α,10α‐EHHC and 3'‐hydroxy‐Δ9‐THC were more active than THC in pharmacological effects such as catalepsy, hypothermia and barbiturate synergism in mice, indicating that these metabolites are active metabolites of THCs. Cannabidiol (CBD), another major component, was biotransfomred to two novel metabolites, 6‐hydroxymethyl‐Δ9‐THC and 3‐pentyl‐6, 7, 7a, 8, 9, 11a‐hexahydro‐1, 7‐dihydroxy‐7,10‐dimethyldibenzo[b,d]oxepin (PHDO) through 8R,9‐epoxy‐CBD and 8S, 9‐epoxy‐CBD as intermediates, respectively, identified by us. Both metabolites have some pharmacological effects comparable to Δ9‐THC. Cannabinol (CBN), the other major component, was mainly metabolized to 11‐hydroxy‐CBN by hepatic microsomes of animals including humans. The pharmacological effects of the metabolite were higher than those of CBN demonstrating that 11‐hydroxylation of CBN is an activation pathway of the cannabinoid as is the case in THCs. Tolerance developed to catalepsy, hypothermia and pentobarbital‐induced sleep prolonging effects of Δ8‐THC and its active metabolite, 11‐hydroxy‐Δ8‐THC. Reciprocal cross‐tolerance also developed to pharmacological effects and the magnitude of tolerance development produced by the metabolite was significantly higher than that by Δ8‐THC indicating that 11‐hydroxy‐Δ8‐THC has important role not only in the pharmacological effects but also its tolerance development of Δ8‐THC. THCs and their metabolites competed with the specific binding of CP‐55,940, an agonist of cannabinoid receptor, to synaptic membrane from bovine cerebral cortex. The Ki value of THCs and their metabolites were closely parallel to their pharmacological effects in mice. A novel cytochrome P450 (cyp2c29) was purified and identified for the first time by us as a major enzyme responsible for the metabolic activation of Δ8‐THC at the 11‐position in the mouse liver. cDNA of cyp2c29 was cloned from a mouse cDNA library and its sequence was determined. All of major P450s involving the metabolic activation of Δ8‐THC at the 11‐position are belonging to CYP2C subfamily in mammalian liver.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82539789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A mixture of the potent neurotoxins tetrodotoxin (TTX) and chiriquitoxin (CHTX) was isolated from the skins of the male and the eggs of the female frog Atelopus chiriquiensis from Costa Rica. Tetrodotoxin was also found in the skin of both populations of Atelopus varius varius and Atelopus varius ambulatorious from Costa Rica. Zetekitoxin(ZTX) was isolated from Atelopus zeteki from Panama. The TTX, CHTX, and ZTX are potent neurotoxins and their toxicities are about the same (ca. 5–11 µg/Kg). The structural studies and biological activities of TTX, CHTX, and ZTX are described.
{"title":"Potent Neurotoxins: Tetrodotoxin, Chiriquitoxin, and Zetekitoxin from Atelopus Frogs in Central America","authors":"Yong Hae Kim, Yun-Bong Kim, M. Yotsu-Yamashita","doi":"10.1081/TXR-120026911","DOIUrl":"https://doi.org/10.1081/TXR-120026911","url":null,"abstract":"A mixture of the potent neurotoxins tetrodotoxin (TTX) and chiriquitoxin (CHTX) was isolated from the skins of the male and the eggs of the female frog Atelopus chiriquiensis from Costa Rica. Tetrodotoxin was also found in the skin of both populations of Atelopus varius varius and Atelopus varius ambulatorious from Costa Rica. Zetekitoxin(ZTX) was isolated from Atelopus zeteki from Panama. The TTX, CHTX, and ZTX are potent neurotoxins and their toxicities are about the same (ca. 5–11 µg/Kg). The structural studies and biological activities of TTX, CHTX, and ZTX are described.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83928407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Animal sera are the only source for antivenom production today. The main disadvantage of heterologous protein products is frequent adverse reactions due to contaminant protein, other than antibody. They are also in very short supply worldwide as traditional manufacturers have discontinued production due to economic constraints. Factors that influence the quality of the product range from the antigen used for immunization, the animal species, the immunization program, and the purification method which must balance purity, efficacy and affordable cost. Throughout the long history of antivenom production, the search for a better quality product has never ended. The ideal antivenom has never been produced and adverse reactions remain a problem. This article summarizes, in brief, the development of antivenom, present production techniques and future directions.
{"title":"Snake Antivenoms: Heterologous and Polyclonal Antisera","authors":"Pannipa Chulasugandha","doi":"10.1081/TXR-120019561","DOIUrl":"https://doi.org/10.1081/TXR-120019561","url":null,"abstract":"Animal sera are the only source for antivenom production today. The main disadvantage of heterologous protein products is frequent adverse reactions due to contaminant protein, other than antibody. They are also in very short supply worldwide as traditional manufacturers have discontinued production due to economic constraints. Factors that influence the quality of the product range from the antigen used for immunization, the animal species, the immunization program, and the purification method which must balance purity, efficacy and affordable cost. Throughout the long history of antivenom production, the search for a better quality product has never ended. The ideal antivenom has never been produced and adverse reactions remain a problem. This article summarizes, in brief, the development of antivenom, present production techniques and future directions.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84678918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil serves as a reservoir for Aspergillus flavus and A. parasiticus, fungi that produce carcinogenic aflatoxins in agricultural commodities. Populations in soil are genetically diverse and individual genotypes show a clustered distribution pattern within fields. Surveys over large geographic regions suggest that climate and crop composition influence species density and aflatoxin‐producing potential. Aflatoxigenic fungi reside in soil as conidia, sclerotia and hyphae, which act as primary inocula for directly infecting peanuts or for infecting aerial crops (corn, cottonseed, tree nuts) through wind and insect dispersal. Infected crops periodically replenish soil populations during drought years.
{"title":"Ecology and Population Biology of Aflatoxigenic Fungi in Soil","authors":"B. Horn","doi":"10.1081/TXR-120024098","DOIUrl":"https://doi.org/10.1081/TXR-120024098","url":null,"abstract":"Soil serves as a reservoir for Aspergillus flavus and A. parasiticus, fungi that produce carcinogenic aflatoxins in agricultural commodities. Populations in soil are genetically diverse and individual genotypes show a clustered distribution pattern within fields. Surveys over large geographic regions suggest that climate and crop composition influence species density and aflatoxin‐producing potential. Aflatoxigenic fungi reside in soil as conidia, sclerotia and hyphae, which act as primary inocula for directly infecting peanuts or for infecting aerial crops (corn, cottonseed, tree nuts) through wind and insect dispersal. Infected crops periodically replenish soil populations during drought years.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85366877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Contact of Lonomia obliqua caterpillars results in skin local inflammation and a bleeding syndrome characterized by hemorrhage and blood incoagulability. Conventional therapy was incapable of alleviating the symptoms. A process for manufacturing a specific antilonomic serum (SALon) by immunizing horses with Lonomia caterpillar bristle extracts (LBE) was developed. LBE exhibited several protein bands on SDS‐PAGE, produced blood incoagulability and lethality in mice, and induced specific antibody production in horses. Sera obtained from immunized horses were rich in specific anti‐LBE antigens antibodies evenly distributed among the horse IgG isotypes. These antibodies were endowed with the ability to recognize various LBE antigens as well as neutralizing their coagulopathy‐inducing activity. The antivenom manufactured according the process was composed of purified and sterilized F(ab′)2 with ED50 = 38.61 μl; potency = 0.29 mg/ml, and a confidence limit of 95% of 0.20–1.36. In a clinical trial SALon was a specific and effective therapeutic agent to treat victims with lonomism. In a single dose of five ampoules (50 ml) it reverts the clinical symptoms, the hemostatic disturbances, and the hemorrhages resulting from the contact of the victims with the L. obliqua caterpillars. One strake observation was the significant reduction in rates of mortality, mainly of envenomed children.
{"title":"Development and Clinical Use of Antilonomic Serum","authors":"W. Dias da Silva","doi":"10.1081/TXR-120019562","DOIUrl":"https://doi.org/10.1081/TXR-120019562","url":null,"abstract":"Contact of Lonomia obliqua caterpillars results in skin local inflammation and a bleeding syndrome characterized by hemorrhage and blood incoagulability. Conventional therapy was incapable of alleviating the symptoms. A process for manufacturing a specific antilonomic serum (SALon) by immunizing horses with Lonomia caterpillar bristle extracts (LBE) was developed. LBE exhibited several protein bands on SDS‐PAGE, produced blood incoagulability and lethality in mice, and induced specific antibody production in horses. Sera obtained from immunized horses were rich in specific anti‐LBE antigens antibodies evenly distributed among the horse IgG isotypes. These antibodies were endowed with the ability to recognize various LBE antigens as well as neutralizing their coagulopathy‐inducing activity. The antivenom manufactured according the process was composed of purified and sterilized F(ab′)2 with ED50 = 38.61 μl; potency = 0.29 mg/ml, and a confidence limit of 95% of 0.20–1.36. In a clinical trial SALon was a specific and effective therapeutic agent to treat victims with lonomism. In a single dose of five ampoules (50 ml) it reverts the clinical symptoms, the hemostatic disturbances, and the hemorrhages resulting from the contact of the victims with the L. obliqua caterpillars. One strake observation was the significant reduction in rates of mortality, mainly of envenomed children.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73097431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The issue of food safety in Africa is one which interacts with and is frequently subjugate to issues of food security, especially in geographic areas where food shortages are caused by recurrent natural weather phenomena such as drought. In addition, many subsistence farming communities in Africa are reliant on the consumption of home‐grown crops, irrespective of the quality considerations normally applied in the developed world. Nevertheless, some African governments have instituted food safety regulations to control mycotoxin, especially aflatoxin, contamination of the national food supply and research into natural occurrence of aflatoxins in a range of local foods is widely conducted. This review summarises the work published in this field through the previous decade. It emphasizes that much of the research effort has been performed in South Africa, Egypt and in various countries in west Africa including Ghana, Nigeria and The Gambia. Although much of the published research deals with levels of aflatoxin contamination in staple foods such as maize and groundnuts, other particularly local foods such as cured and smoke‐dried fish have been implicated as sources of dietary aflatoxin in various areas of Africa. The conclusion to be drawn from this survey is that aflatoxin exposure remains an important aspect of food safety which needs to be addressed by African communities.
{"title":"Aflatoxin and Food Safety: Recent African Perspectives","authors":"G. Shephard","doi":"10.1081/TXR-120024094","DOIUrl":"https://doi.org/10.1081/TXR-120024094","url":null,"abstract":"The issue of food safety in Africa is one which interacts with and is frequently subjugate to issues of food security, especially in geographic areas where food shortages are caused by recurrent natural weather phenomena such as drought. In addition, many subsistence farming communities in Africa are reliant on the consumption of home‐grown crops, irrespective of the quality considerations normally applied in the developed world. Nevertheless, some African governments have instituted food safety regulations to control mycotoxin, especially aflatoxin, contamination of the national food supply and research into natural occurrence of aflatoxins in a range of local foods is widely conducted. This review summarises the work published in this field through the previous decade. It emphasizes that much of the research effort has been performed in South Africa, Egypt and in various countries in west Africa including Ghana, Nigeria and The Gambia. Although much of the published research deals with levels of aflatoxin contamination in staple foods such as maize and groundnuts, other particularly local foods such as cured and smoke‐dried fish have been implicated as sources of dietary aflatoxin in various areas of Africa. The conclusion to be drawn from this survey is that aflatoxin exposure remains an important aspect of food safety which needs to be addressed by African communities.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74175270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Fry, K. Winkel, J. C. Wickramaratna, W. Hodgson, W. Wüster
The ubiquity of venom variation in snakes poses special problems for the manufacture of antivenom and has undermined the commercial attractiveness of this class of therapeutic agent. In particular, it has been amply documented that both interspecific and intraspecific variation in venom composition can affect the neutralisation capacity of antivenoms. This may be exacerbated by the selective use of tests of venom toxicity and antivenom efficacy, such as the lethal dose and ED50, resulting in inadequate neutralisation of time, rather than dose, dependent toxins, particularly enzymes involved in defibrinogenating, haemorrhagic and necrotising venom activities. The clinical consequences can be reduced efficacy against some important venom activities or even complete treatment failure in critical envenomations. All these factors, combined with the ongoing reduction in the number of antivenom manufacturers world‐wide, and concomitant contraction in the range of available antivenoms, present significant challenges for the treatment of snakebite in the 21st century.
{"title":"Effectiveness of Snake Antivenom: Species and Regional Venom Variation and Its Clinical Impact","authors":"B. Fry, K. Winkel, J. C. Wickramaratna, W. Hodgson, W. Wüster","doi":"10.1081/TXR-120019018","DOIUrl":"https://doi.org/10.1081/TXR-120019018","url":null,"abstract":"The ubiquity of venom variation in snakes poses special problems for the manufacture of antivenom and has undermined the commercial attractiveness of this class of therapeutic agent. In particular, it has been amply documented that both interspecific and intraspecific variation in venom composition can affect the neutralisation capacity of antivenoms. This may be exacerbated by the selective use of tests of venom toxicity and antivenom efficacy, such as the lethal dose and ED50, resulting in inadequate neutralisation of time, rather than dose, dependent toxins, particularly enzymes involved in defibrinogenating, haemorrhagic and necrotising venom activities. The clinical consequences can be reduced efficacy against some important venom activities or even complete treatment failure in critical envenomations. All these factors, combined with the ongoing reduction in the number of antivenom manufacturers world‐wide, and concomitant contraction in the range of available antivenoms, present significant challenges for the treatment of snakebite in the 21st century.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79415474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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