ISSN:1056-9014    

DOI:10.1002/nt.2620030402

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

ISSN:1056-9014    

DOI:10.1002/nt.2620030403

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe impact of mycotoxins on human and animal health is now increasingly recognised. Mycotoxin entry to the human and animal dietary systems is mainly by ingestion but increasing evidence also points at entry by inhalation. Mycotoxins exhibit a wide array of biological effects and individual mycotoxins can be mutagenic, carcinogenic, embryotoxic, teratogenic, or oestrogenic. Average levels of ingestion of currently known mycotoxins in most EEC countries are rather low. Little is known about the consequences to humans of such mycotoxin intakes. Establishing a causal relationship between mycotoxin exposure and human disease is complicated by uncertainties associated with human epidemiological studies. Analysis of mycotoxin adducts in human populations can act as a surrogate for human genotoxicity. Mycotoxins can also be immunosuppressive and appear to involve cellular immune phenomena and non‐specific humoral factors associated wtih immunity. © 1995 Wiley‐Liss,

ISSN:1056-9014    

DOI:10.1002/nt.2620030404

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractFusarium moniliformeis one of the predominant fungi associated with com intended for human and animal consumption world‐wide. Fumonisins, food‐bome carcinogens that occur naturally in com, were first isolated and chemically characterized in South Africa in 1988. The major metabolite, fumonisin B1 (FB1), was subsequently shown to cause leukoencephalomalacia (LEM) in horses, pulmonary edema syndrome (PES) in pigs, and liver cancer in rats. FB1, is also a cancer promoter and initiator in rat liver; hepatotoxic to horses, pigs, rats, and vervet monkeys; cytotoxic to mammalian cell cultures; and phytotoxic to several plants. Fumonisins in home‐grown com have been associated with an elevated risk for human esophageal cancer in Transkei and China. There is a close structural similarity between fumonisin and sphingosine, and fumonisins are the first known naturally occurring inhibitors of sphingolipid biosynthesis. The natural occurrence of FB1together with FB2and FB3, has been reported in commercial com and/or combased feeds and foods from Argentina, Australia, Brazil, Botswana, Bulgaria, Canada, China, Egypt, France, Italy, Japan, Kenya, Hungary, Nepal, Peru, South Africa, Switzerland, United States, and Zimbabwe. It is imperative that safe levels of fumonisins in human foods and animal feeds should be determined and realistic tolerance levels established as soon as possible. © 1995 Wiley‐L

ISSN:1056-9014    

DOI:10.1002/nt.2620030405

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractMycotoxin contamination of crops may cause economic losses at all levels of food and feed production including crop and animal production, and crop distribution and processing. The national economy would be affected adversely by losses incurred by crop and livestock producers and the multiplier effect this has on other industries as a result of the reduced spending power of producers. Costs of chemical analyses, quality control and regulatory programs, research and development, extension services, law suits, and the cost of human illnesses must all be bome by the national economy. The value of the losses encountered depends on grain, animal, and animal product prices, interest rates, degree of contamination, and other economic variables. Even during favourable seasons it is likely that millions of dollars are lost as a result of the contamination of crops with mycotoxins.Many compounds and treatments have been tested in order to reduce mycotoxin concentrations in food and feed or to alleviate their adverse effects on animals. Some of these treatments show promising prospects for commercial application, while others have had commercial applications already. However, until reliable, cost‐effective, commercially applicable methods are more widely available, problems associated with mycotoxin contamination and the economic losses resulting, will continue to be seen in food and agriculture industries. Published 1995 Wiley‐Liss,

ISSN:1056-9014    

DOI:10.1002/nt.2620030406

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractPractical and effective strategies for the detoxification of aflatoxins are critically needed. We have shown that a phyllosilicate clay (HSCAS): i) tightly binds aflatoxins in aqueous solutions, including milk; ii) markedly decreases the bioavailability of radiolabeled aflatoxins; iii) greatly diminishes aflatoxicosis in young animals, i.e., rats, chickens, turkeys, lambs, and pigs; and iv) reduces the level of aflatoxin M1in the milk from lactating dairy cattle and goats. In further studies, ligands with one or more of the functional groups in common with aflatoxin were reacted with HSCAS in vitro in an attempt to elucidate the specificity and mechanism of tight binding (or chemisorption). A chemisorption index (Cα) was developed, allowing for direct comparison of various clay and zeolitic minerals with HSCAS. Chemisorption indices were determined by HPLC analysis of extracts of the supematants and sorbed pellets (exhaustively extracted with methanol and chloroform). The β‐dicarbonyl system of aflatoxin was found to be essential for tight binding by HSCAS. Comparison of the chemisorption indices from various classes of compounds with spectral data (DRIFTS) indicated that the molecular mechanism of aflatoxin binding may involve the chelation of metal ions in HSCAS with the β‐dicarbonyl moiety in aflatoxin. Computer modeling was utilized to provide additional information. Preliminary evidence suggests that aflatoxin B1may react at surfaces and within the interlayers of HSCAS particles. With knowledge of the mechanism involved, it has been possible to further enhance the propensity of HSCAS for aflatoxins. © 1995 Wiley‐

ISSN:1056-9014    

DOI:10.1002/nt.2620030407

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe frequent occurrence of ochratoxin A (OA) in food and feed commodities and the high incidence of human exposure, as confirmed by different surveillance studies initiated several investigations devoted to elucidating the molecular mechanisms underlying OA toxicity. Previous studies indicated that the primary effects of OA are the inhibition of tRNA synthetase, the inhibition of mitochondrial respiration, and a disturbance of intracellular calcium homeostasis inherent to lipid peroxidation processes. We here report the effect of OA on a number of toxicological endpoints including cytotoxicity in different cell lines and effects on macromolecular synthesis and cell proliferation in primary cultures of hepatocytes at concentrations corresponding to overall exposure levels. These studies provide evidence that prominent toxicological effects might be linked to biotransformation processes. Analysis of hepatic biotransformation resulted in the detection of a number of distinct stable OA‐metabolites. As metabolic activation has also been identified as an essential step in OA mutagenicity, the biological relevance on this mechanistic data is discussed. © 1995 Wiley‐Liss,

ISSN:1056-9014    

DOI:10.1002/nt.2620030408

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

ISSN:1056-9014    

DOI:10.1002/nt.2620030409

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractAlthough the awareness that natural compounds in foodstuffs can have implications for human health is growing, there is a lack of data on the toxicology and occurrence. To enable the safety evaluation of inherent plant toxins adequate texicological data are necessary. Of most inherent plant toxins at best only limited toxicological data are available, which makes it impossible to perform an accurate safety evaluation. This limited knowledge of inherent plant toxins permits the mystical claim of safety on the basis of history of food use, and thus the development of specific food safety regulation has been postponed. To further develop flexible and adequate regulation, for at least some inherent plant toxins, an adequate set of toxicological data should be available in order to verify and validate the initial regulation. Several problems (e.g., availability of the plant toxin or accuracy of historical human toxicity data) which arise when gathering the necessary data and the development of regulations are discussed and elaborated with a few examples such as solanum alkaloids and glucosinolates.As long as nobody is held responsible to study safety aspects of inherent plant toxins, the lack of data will persist. Therefore a certain level of regulation should be recommended to provide the data needed. Such safety research projects integrated with new agricultural developments should be endorsed by the European Union and other international bodies. © 1995 Wiley‐Liss, I

ISSN:1056-9014    

DOI:10.1002/nt.2620030410

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractPyrrolizidine alkaloids are among the most significant plant chemicals causing disease in animals and humans. After absorption from the gut, the compounds are converted to electrophilic pyrroles in the liver which, apart from causing damage to this organ, may escape to cause injury to extraheptic tissues such as the lungs, heart, and kidneys.A group of compounds more recently found to be associated with neurotoxicity are various polyhydroxyalkaloids which are able to interfere with polysaccharide metabolism. They are able to inhibit lysosomal monosaccharidases by virtue of their structural resemblance to the transition state of particular sugar molecules. The resulting lysosomal storage diseases have pathology identical to that of the respective congenital and heritable lysosomal storage diseases which occur in animals and humans.Consumption of cycad plants by cattle may cause a neurotoxicity characterised mainly by a posterior sensory ataxia. In recent years, cycads are considered to be a risk factor for a spectrum of progressive neuro degenerative diseases of humans in the Western Pacific region. The known toxins in the plant are the methylazoxymethanol glycosides which are hepatotoxic and carcinogenic, and the neurotoxic non‐protein amino acid β‐methylaminoalanine.A plant carcinogen which can be of great abundance in the nutritional environment is the illudine norsesquiterpene glucoside ptaquiloside which is found in bracken fern. This is the only plant carcinogen which causes natural outbreaks of bladder and/or intestinal cancer in livestock.Many legumes contain phytooestrogens, notably isoflavones. Consumption of these compounds at high levels by sheep can cause extensive lesions of the genitalia of females and castrated males. A chronic long‐term effect of excessive oestrogen intake in ewes is “masculinization” of the internal genitalia leading to reduced fertility. The presence of such compounds in the diet may be associated with reproductive disorders in man. © 1995 Wile

ISSN:1056-9014    

DOI:10.1002/nt.2620030411

出版商:John Wiley&Sons, Inc.    

年代:1995

数据来源: WILEY