SEARCH · PubMed Health

Results for “Aflatoxin”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources

PubMed2004

Determination of aflatoxins B1, G1, B2 and G2 in medicinal herbs by liquid chromatography-tandem mass spectrometry.

An easy method for the determination of aflatoxins B1, G1, B2 and G2 in Rhammus purshiana by LC coupled to mass spectrometry has been developed. Aflatoxins were extracted with a mixture of methanol and water and then it was purified by solid-phase clean-up using a polymeric sorbent, not described previously, for the determination of these toxins. The eluted extract was injected into the chromatographic system using a reversed-phase C18 short column with an isocratic mobile phase composed of methanol-water (30:70). A single-quadruple mass spectrometry using an electrospray ionization source operating in the positive ion mode was used to detect aflatoxins due to derivatization presenting several disadvantages. Recoveries of the full analytical procedure were 110% for aflatoxin B1, 89% for aflatoxin B2, 81% for aflatoxin G1 and 77% for aflatoxin G2. Detection limit (S/N = 3) was 10 ng and quantification limit (S/N = 10) was 25 ng, calculated as amount in medicinal herb.

Aflatoxins↗

PubMed2005

A cross sectional study of hepatitis B, C, some trace elements, heavy metals, aflatoxin B1 and schistosomiasis in a rural population, Egypt.

Chronic liver diseases are disastrous to health. Many factors are associated with their prevalence, hence endemicity. These are mainly infectious, parasitic and toxic. A survey was conducted in a village south to Cairo. Large industries concerned with iron and steel industry, metals smelting, cement manufacturing and electric station were located north to the village. A systematic random sample of houses was selected. All individuals inside the houses were invited to share in the study. Sample size was 84 individuals. Hepatitis markers were done (HBsAg and anti-HCV antibodies). The levels of some heavy metals were assessed; which were lead, mercury, arsenic, aluminum, manganese, nickel, chromium and cadmium. Levels of some trace elements were assessed. These were copper, iron, selenium and zinc. Aflatoxin B1 was assessed in serum. Assessment of schistosomal circulating antigen and antibodies was carried out. Abdominal ultrasonograghy was done to assess liver condition. Univariate logistic regression analysis was done to assess the association between studied variables and HBsAg or anti-HCV sero-positive subjects. The association between studied variables and bilharzial or fatty liver, diagnosed by ultrasonography, were also assessed. The univariate logistic regression analysis revealed odds ratios at the following results. For HBsAg seropositive subjects, aflatoxin B1, lead, chromium and schistosomal antigen and antibodies were higher than negative ones where odds ratios were; 6.2, 1.6, 1.6, 1.6 and 1.7, respectively. None of the variables showed statistically significant difference. For anti-HCV antibodies sero-positive subjects, aflatoxin B1 and chromium had the highest odds ratios among the studied variables, (odds ratios were 2.5 and 2.4, respectively). Bilharzial liver showed higher significant positivity of anti-HCV antibodies and insignificant decreased level of zinc than negative ones (odds ratios were 7.2 and 4.5, respectively). Fatty liver cases showed higher statistically significant positivity of anti-HCV antibodies and chromium than negative ones. Odds ratios were 8.0 and 7.1, respectively. Statistically significant lower level of aflatoxin B1 was shown in fatty liver than normal liver subjects. Multivariate logistic regression analysis for fatty liver showed that only anti-HCV antibodies sero-positivity had statistically significant odds ratio in comparison to chromium level and aflatoxin B1. It is concluded that some heavy metals, and Aflatoxin B1 had a definite association with liver diseases in the area under study. Having anti-HCV antibodies had a relation with fatty liver and with bilharzial liver more than having HBsAg. It is recommended that environmental management to factories nearby the village is urgently needed to decrease exposure to heavy metals. Prevention of hepatitis infection and aflatoxin exposure through different means is also recommended, other wise health care authorities would be confronted with unusual cases of HCC in the nearby future.

Adolescent↗

PubMed1991

Evaluation of a commercial immunoassay system for sulfamethazine and aflatoxin detection in biological fluids and feeds.

Commercial immunoassay systems produced by International Diagnostics to analyze for sulfa drugs and aflatoxin residues have been evaluated with milk, urine, feed and serum samples. Neither system produced satisfactory results with feeds. The sulfa test reproducibility was good enough to provide semiquantitative results on milk (40 ul sample) and urine, but should be regarded as qualitative on urine or feed. The reproducibility of the aflatoxin test was acceptable for semiquantitative use on serum, but should be regarded as qualitative on urine and semiquantitative on milk with a solid phase concentration. The overall reproducibility was at least +/- 10% if the test was used semiquantitatively. The sensitivity of the test was 10 ng for both sulfamethazine and aflatoxin B1. The range of the color change was very narrow (0-20 ng). The aflatoxin test was designed for aflatoxin B1 and was roughly twice as sensitive to B1 as to M1 aflatoxin. These procedures can be used on appropriate matrices at suitable sensitivities to rapidly screen samples for sulfa drugs and aflatoxin residues. The use of proper standards to demonstrate effectiveness in each matrix is very important.

Aflatoxins↗

PubMedDate not supplied

Immunoaffinity column coupled with solution fluorometry or liquid chromatography postcolumn derivatization for determination of aflatoxins in corn, peanuts, and peanut butter: collaborative study.

An AOAC/IUPAC (International Union of Pure and Applied Chemistry) collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column for the determination of aflatoxin. The test portion is extracted with methanol-water (7 + 3), filtered, diluted to less than 30% methanol with water, and applied to the affinity column. The column is washed with water and the concentrated aflatoxins are eluted with methanol. Total aflatoxins are determined by solution fluorometry with bromine (SFB), and individual toxins are determined by reverse-phase liquid chromatography with postcolumn derivatization with iodine (PCD). Corn naturally contaminated with aflatoxins, and peanuts, peanut butter, and corn containing added aflatoxins (B1:B2:G1:G2 = 7:1:3:1) were sent to 24 collaborators in the United States, France, Canada, and the Republic of South Africa. Twelve collaborators used the SFB method, 9 used the PCD method, and 3 used both SFB and PCD methods. Twenty collaborators completed the study (10 used the SFB method, 7 used the PCD method, and 3 used both SFB and PCD methods). Test portions were spiked at 10, 20, and 30 ng/g. For SFB analyses, recoveries of total aflatoxins were 123, 105, and 107%, respectively; the relative standard deviation for repeatability (RSDr) ranged from 11.75 to 16.57%, and the relative standard deviation for reproducibility (RSDR) ranged from 10.97 to 33.09%. For PCD analyses, recoveries were 81, 81, and 83%, respectively; the RSDr ranged from 5.20 to 17.22%, and the RSDR ranged from 4.68 to 50.77%. The RSDr for aflatoxins B1 and G1 for spiked test portions ranged from 5.45 to 23.55%, and the RSDR ranged from 4.21 to 57.28%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxins↗

PubMed1975

In vitro metabolic conversion of aflatoxins and benzo(alpha)pyrene to nucleic acid-binding metabolites.

An aflatoxin B1 metabolite was found to become covalently bound to rat liver RNA and calf thymus DNA in vitro, and it formed complexes with increased spectral absorbance in the 360 nm region. The formation of such complexes was reduced nicotinamide adenine dinucleotide phosphate and microsome dependent, was inhibited by theta-diethylaminoethyl diphenylpropylacetate-HC1, and by CO and N2, when the latter were used to replace the gas phase of the incubations. The formation of the complexes was enhanced about 2-fold with cicrosomes from phenobarbital-treated rats but not from 3-methylcholanthrene-treated rats. More binding was observed with DNA than RNA. Dentured DNA was about 70% as effective as native DNA. Nucleic acids from various sources showed the following order of binding potency: DNA from Micrococcus luteus greater than DNA from calf thymus equal to DNA from rat liver greater than RNA from rat liver greater than transfer RNA from rat liver. In the presence of reduced nicotinamide adenine dinucleotide phosphate and microsomes from phenobarbital-treated rats, aflatoxin G1 was also converted into metabolite(s) that became covalently bound to nucleic acids and formed complexes with increased spectral absorbances in the 360 nm region: this reaction was also inhibited by theta-diethylaminoethyl diphenylpropylacetate-HC1. Under the same conditions, aflatoxin B2, aflatoxin G2, aflatoxin B2a, and "Compound 11," which lack a C2-C3 double bond, did not show any noticeable binding to either DNA or RNA. These data strongly support the concept that the microsomal mixed-funciton oxygenase-catalyzed oxidation of the C2-C3 double bond of aflatoxins is a prerequisite for the formation of nucleic acid-binding metabolites. Microsomes from untreated, phenobarbital-treated, and 3-methylcholanthrene-treated rats were compared in vitro for their ability to catalyze the formation of DNA-binding metabolites from aflatozin B1 and benzo(a)pyrene. In assays involving benzo(a)pyrene, microsomes from 3-methylcholanthrene-treated rats were 12- and 5-fold more active than microsomes from untreated and phenobar-bital-treated rats, respectively. This is in contrast to the results obtained with aflatoxin B1 and suggests that different enzymes in the hepatic microsomal mixed-function oxygenase complex are involved in the generation of reactive metabolites from various polycyclic hydrocarbons.

Aflatoxins↗

PubMedDate not supplied

Simple, rapid cleanup method for analysis of aflatoxins and comparison with various methods.

A method is described for simple and rapid determination of aflatoxins in corn, buckwheat, peanuts, and cheese. Aflatoxins were extracted with chloroform-water and were purified by a Florisil column chromatographic procedure. Column eluates were concentrated and spotted on a high performance thin layer chromatographic (HPTLC) plate, which was then developed in chloroform-acetone (9 + 1) and/or ether-methanol-water (94 + 4.5 + 1.5) or chloroform-isopropanol-acetone (85 + 5 + 10). Each aflatoxin was quantitated by densitometry. The minimum detectable aflatoxin concentrations (micrograms/kg) in various test materials were 0.2, B1; 0.1, B2; 0.2, G1; 0.1, G2; and 0.1, M1. Recoveries of the aflatoxins added to corn, peanut, and cheese samples at 10-30 micrograms/kg were greater than 69% (aflatoxin G2) and averaged 91%, B1; 89%, B2; 91%, G1; 78%, G2; and 92%, M1. The simple method described was compared with the AOAC CB method, AOAC BF method, and AOAC milk and cheese method. These methods were applied to corn, peanut, and cheese composites spiked with known amounts of aflatoxins, and to naturally contaminated buckwheat and cheese. Recoveries were much lower for the BF method compared with our simple method and the CB method.

Aflatoxins↗

PubMed1979

Production of aflatoxin in cocoa beans.

Aflatoxin was produced in both non-autoclaved and autoclaved Ivory Coast cocoa beans inoculated with Aspergillus parasiticus NRRL 2999 under optimum laboratory growth conditions. Total aflatoxin levels ranged from 213 to 5597 ng/g substrate. Aflatoxin was quantitated by using high pressure liquid chromatography (HPLC). Raw, non-autoclaved cocoa beans, also inoculated with aspergilli, produced 6359 ng aflatoxin/g substrate. Variation in aflatoxin production between bean varieties was observed. Total aflatoxin levels of 10,446 and 23,076 ng/g substrate were obtained on Ivory Coast beans inoculated with A. parasiticus NRRL 2999 and NRRL 3240, respectively. Aflatoxin production on Trinidad and Malaysian beans was 28 and 65 ng aflatoxin/g substrate. These data support previously reported low level natural aflatoxin contamination in cocoa.

Aflatoxins↗

PubMed1984

Effects of aflatoxin ingestion on the development of Moraxella bovis infectious bovine keratoconjunctivitis.

A study was conducted to determine whether measured doses of aflatoxin given under different schedules would influence the pathogenesis of Moraxella bovis induced infectious bovine keratoconjunctivitis (IBK). Calves were allotted to 4 groups (groups I-IV) of 9, 9, 9, and 8 calves, respectively. Group I calves were given aflatoxin for 11 consecutive days starting 5 days before their eyes were exposed to M. bovis. Group II calves were given aflatoxin for 5 consecutive days starting 7 days after their eyes were exposed to M. bovis. Group III calves were given aflatoxin for 5 consecutive days starting 21 days after their eyes were exposed to M. bovis. Group IV calves were not given aflatoxin; but their eyes were exposed to M. bovis on the same day as were the eyes of calves in groups I-III; these calves served as controls. Aflatoxin had little if any influence on the pathogenesis of IBK under the conditions of this study. The results did not rule out an exacerbating effect of M bovis infection on aflatoxicosis in calves. Calves with the highest concentration of aflatoxin in their blood had the more severe signs of aflatoxicosis. Possible reasons for the equivocal results are discussed.

Aflatoxins↗

PubMedDate not supplied

Influence of dietary aflatoxin on the severity of Eimeria acervulina infection in broiler chickens.

Broiler chicks (Hubbard x Hubbard) receiving 2.5 microgram of aflatoxin/g of diet and inoculated with sporulated oocysts of Eimeria acervulina gained significantly less weight than chicks receiving either aflatoxin or coccidia alone. Aflatoxin alone affected body weight more in females than males. Blood parameters, however, showed no sex-related differences to E. acervulina or aflatoxin. E. acervulina had no effect on packed cell volume, red cell number, or hemoglobin levels. Gross lesions in the intestine caused by the coccidia appeared the same with or without dietary aflatoxin. Either aflatoxin or E. acervulina alone reduced the plasma pigment. When both were present, depigmentation was greater with some strains of coccidia than with either alone. Aflatoxin alone reduced the plasma levels of cholesterol and protein. The effect of E. acervulina on cholesterol or protein, with or without aflatoxin, depended on the coccidial strain used.

Aflatoxins↗

PubMed1982

Susceptibility of strawberries, blackberries, and cherries to Aspergillus mold growth and aflatoxin production.

The susceptibility of blackberries, cherries, and strawberries to Aspergillus growth and aflatoxin production has been examined. Three aflatoxigenic isolates of Aspergillus, A. flavus ATCC 15548 and NRRL 3251 as well as A. parasiticus NRRL 2999, were cultured on homogenates of the fruits for 14 days at 28 +/- 2 degrees C. Percent mycelial growth and spore infestation were determined each day with a calibrated grid. At day 14 each culture was frozen at -5 degrees C until aflatoxins were extracted with methylene chloride and water. Aflatoxins were separated by thin layer chromatography (TLC) with benzene-methanol-acetic acid (90 + 5 + 5). This extraction and solvent system provided satisfactory separations of the aflatoxins and was free of background interference on the TLC plates. Although all fruits served as substrates for both Aspergillus growth and aflatoxin production, cherries appeared to be a more favorable substrate than did blackberries, and the latter was more favorable than strawberries. Whereas A. flavus produced both B1 and G1 on all substrates, it yielded B2 and G2 only on cherries. Although A. parasiticus NRRL 2999 synthesized B1, B2, G1, and G2 on both blackberries and cherries, no aflatoxins were detected on strawberries. In contrast, A. flavus NRRL 3251 failed to produce detectable levels of aflatoxin on any substrate. All substrates supported both mycelial growth and subsequent sporulation with cherries greater than blackberries greater than strawberries.

Aflatoxins↗

PubMed1982

High pressure liquid chromatographic determination of aflatoxins by using radial compression separation.

A rapid method for the determination of aflatoxins was developed using high pressure liquid chromatography and a radial compression separation system. A standard solution of aflatoxins B1, B2, G1, G2, and M1 was analyzed solution of aflatoxins B1, B2, G1, G2, and M1 was analyzed at flow rates of 2.0 and 6.0 mL/min. Retention times, peak heights, and peak areas were reproducible over a 3-day period. Coefficients of variation for aflatoxin B1 at 2.0 and 6.0 mL/min were, respectively, 1.04 and 0.87% (retention time); 2.9 and 4.7% (peak height); and 8.2 and 4.7% (peak area). At 6.0 mL/min there was an approximate 25% loss in sensitivity but a greater than 50% reduction in retention time. Separation of all the aflatoxins was excellent using a dual flow rate of 2.0 mL/min with a change to 8.0 mL/min at 15 min post-injection. The applicability of the radial compression separation system for the rapid determination of aflatoxins in human tissues was also tested. Spiked samples of liver, serum, and urine-showed good resolution of all aflatoxin peaks at the higher flow rates.

Aflatoxins↗

PubMedDate not supplied

[Improved method of determining the aflatoxin content in different food products of plant origin].

The authors offer an improved method for detection, identification and quantitation of aflatoxins, fit for series analyses. The method includes extract purification by means of two-dimensional thin-layer chromatography and quantitative determination of aflatoxin from their specific fluorescence. Combination of the techniques included in the method enables one to separate aflatoxin from interfering substances in extracts of any products of plant origin and excludes the attainment of pseudopositive results. The method was made use of for studying contamination of 145 samples of foods. Aflatoxin B1 was found in some of the samples. The maximal content of the aflatoxin was detected in corn and peanut. Apart from aflatoxin B1, the corn samples were demonstrated to contain aflatoxins B2, G1, and G2.

Aflatoxins↗

PubMed1995

Alteration of glucose tolerance in mice fed low levels of aflatoxins and with depressed glyoxalase-I activity.

Glyoxalase-I activity plays an important role in glucose metabolism and has been reported to be depressed in mice fed low levels of aflatoxin B1. In the present study examination of glyoxalase-I activity, glucose tolerance and pancreatic beta cell sensitivity was made in mice fed 0.045 ng aflatoxin B1 + 0.450 ng aflatoxin G1/g feed prenatally and for 6 mo after birth. After glucose challenge the ratios between 0-h and 2-h serum glucose levels were significantly higher than controls, indicating an increase in tolerance of glucose in the aflatoxin-fed mice with lower glyoxalase-I activity. Pancreatic beta cell sensitivity to stimulation by tolbutamide was similar in both groups. However, liver malonic dialdehyde was significantly higher in the aflatoxin-fed mice, suggesting that the altered tolerance for glucose in the aflatoxin-fed mice might be a consequence of aflatoxin mediated peroxidative actions in the liver.

Aflatoxins↗

PubMed1976

Species differences in the metabolism of aflatoxin B1.

The metabolism of aflatoxin B1 in a number of animals was investigated. Aflatoxin B1 is metabolized relatively more slowly in liver slices of sheep than in the mouse, goat, guinea-pig, rabbit and golden hamster. The rate of metabolism of the toxin by the 10,000 g supernatant is faster than the metabolism by liver slices. This may be as a result of the substrate not penetrating the liver cells readily. Species difference exist in the in vitro metabolism of aflatoxin B1 by hydroxylation and demethylation. The sheep and White Rock cockerel demethylate aflatoxin B1 poorly but the dog and duck do not demethylate the toxin at all. Of the animals studied, the duck, mouse and White Rock cockerel do not produce aflatoxin M1 at all. The sheep and dog produce aflatoxin M1 in comparatively large amounts, while the rat, goat and golden hamster produce aflatoxin M1 in smaller quantities.

Aflatoxins↗

PubMed1977

[Determination and occurence of aflatoxin M1 and B1 in milk and dairy products].

The described method enables a simultaneous identification and determination of aflatoxin M1 and B1 in milk and dairy products by means of a self-registering fluorescence spectrophotometer with a thin-layer chromatographic accessory, directly from the plate. The semiquantitative estimation on the thin-layer chromatographic plate enables also routine analyses in the hygienic practice. The recovery rates for aflatoxin M1 and B1 in milk are about 83 and 82%, respectively -- the detection limit is about 0.1 microng per kg. The recovery rates for aflatoxin M1 and B1 in milk powder are about 89 and 94%, respectively -- the detection limit is bout 0.5 microng per kg. The reproducibility is given with a standard deviation between +/- 1.1 and 6,3% and a variation coeffecient of 1.3 and 6.7, respectively. 4 of 24 analized samples of commercial winter milk were aflatoxin M1-positive, whereas aflatoxin B1 could not be found. One of the milk powder products, a sample of the infant food, "Ki-Na", made in the GDR, contained, however aflatoxin B1. Aflatoxin M1 could not be found. Food-hygienic-toxicological conclusions are discussed.

Aflatoxins↗

PubMed1996

Molecular biomarkers for aflatoxins: from adducts to gene mutations to human liver cancer.

Over the past 30 years there have been extensive efforts to investigate the association between aflatoxin exposure and human liver cancer. These studies have been hindered by the lack of adequate dosimetry data on aflatoxin intake, excretion, and metabolism in people, as well as by the general poor quality of worldwide cancer morbidity and mortality statistics. These realities have spurred the efforts to develop new technologies to assess exposure status and risk for aflatoxins, and these agents are among the few environmental carcinogens for which quantitative risk assessments have been attempted. One of the goals of these risk assessments has been the development of primary and secondary preventive intervention methods to lower the human health impact from aflatoxin exposures. The long-term goal of the research described herein is the application of biomarkers to the development of preventive interventions for use in human populations at high risk for cancer. Several of the aflatoxin-specific biomarkers have been validated in epidemiologic studies and are now available for use as intermediate biomarkers in prevention trials. The development of these aflatoxin biomarkers has been based upon the knowledge of the biochemistry and toxicology of aflatoxins gleaned from both experimental and human studies. These biomarkers have been utilized subsequently in experimental models to provide data on the modulation of the markers under different situations of disease risk. This systematic approach provides encouragement for preventive interventions and should serve as a template for the development for the development and validation of other chemical-specific biomarkers and their application to cancer or other chronic diseases.

Aflatoxins↗

PubMedDate not supplied

Robotic automated analysis of foods for aflatoxin.

Immunoaffinity column-based sample preparation procedures for determination of aflatoxins B1, B2, G1, and G2 in several food matrixes and aflatoxin M1 in milk have been automated by using flexible automation, or robotics. Components used to assemble the system were purchased commercially or developed and built in-house. A liquid-level sensor developed in-house to assist elution of the immunoaffinity column is described. After immunoaffinity column cleanup, aflatoxins are separated by reversed-phase liquid chromatography and determined by fluorescence without derivatization. Mean recoveries of aflatoxins B1, B2, and G1 added to corn and nuts at 9-36 ng/g total aflatoxins were > 85% (coefficient of variation [CV] = 16%). Recoveries of aflatoxin G2 averaged 50% (CV = 28%). Recoveries of aflatoxin M1 added to milk at 0.12-0.50 ng/mL averaged 78% (CV = 19%). The ability of the automated system to reproduce its results is demonstrated by the fact that the CV of replicate assays is generally better than 10%. Comparability between the automated procedure and the AOAC official method is demonstrated.

Aflatoxins↗

PubMed1996

Screening of aflatoxins in Shiro and ground red pepper in Addis Ababa.

Aflatoxin contamination of Shiro and ground red pepper samples collected from government owned good stores, retail shops and open markets in. Addis Ababa was investigated. From sixty samples each of ground red pepper and Shiro, 8 (13.33%) and 5 (8.33%) were positive for aflatoxins, respectively. Only aflatoxin B1 was detected in both types of foodstuff. There was no significant difference between the proportion of aflatoxin contained in both ground red pepper and Shiro samples. Aflatoxin levels in Shiro and ground red pepper positive samples ranged from 100 to 500 ppb and 250 to 525 ppb, respectively. The mean levels of contamination by aflatoxin in ground red pepper was significantly higher (p < 0.05) than that of Shiro. Though statistically not significant, the number of positive samples were more in samples from open markets when compared to samples from government owned food stores and retail shops. Conclusions are drawn that ground red pepper and shiro traded in Addis Ababa can be considered as high risk commodities for which routine survey of aflatoxins may be necessary.

Aflatoxins↗