PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Aflatoxin M1”

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 379 records · Page 21Linked to original sources
PubMed1982

Binding of aflatoxin B1, G1 and M to plasma albumin.

The aflatoxins B1, G1 and their metabolites exist in the systemic blood as protein conjugate. This conjugation is specific to plasma albumin and proceeds enzymatically by liver and kidney cells. The aflatoxin-albumin conjugate is permanent and the conjugation is an irreversible one. This may interpret the acute liver damage of animal ingested a single dose of aflatoxin (3,4). The existence of bound aflatoxin-albumin in the systematic blood could be considered as one factor of low excretions of aflatoxins and their metabolites in urine (5,6,7).

Aflatoxin B1↗
PubMed1996

Distribution and induction of aflatoxin B1-9a-hydroxylase activity in rat liver parenchymal and non-parenchymal cells.

Chronic administration of aflatoxin B1 (AFB1) to rats gives rise to hepatocellular and cholangiocellular carcinomas without affecting Kupffer and endothelial cells. The enzymatic conversion of AFB1 to AFB1-8,9-epoxide is the critical step in the activation of the myocotoxin, while the conversion of AFB1 to aflatoxin M1 (AFM1), catalyzed by the AFB1-9a-hydroxylase, is considered to be a detoxication route for the toxin. In the present study the distribution and inducibility of AFB1-9a-hydroxylase were analyzed in microsomes derived from freshly isolated liver parenchymal (PC) and nonparenchymal cells (i.e. Kupffer + endothelial cells, NPC). AFB1-9a-hydroxylase activity was clearly measurable in NPC and similar to that of PC. In NPC the rate of formation of AFM1 was higher (when incubating with 16 microM AFB1) than or similar (with 128 microM AFB1) to that of AFB1-8,9-epoxide, while in PC it was significantly lower. Taken together, these results suggest that the AFB1-9a-hydroxylase activity might be particularly important in NPC to protect these cells from AFB1 by converting it to a significantly less mutagenic metabolite and by reducing the amount of AFB1 available for epoxidation. Furthermore, it is shown that AFB1-9a-hydroxylase activity is inducible by phenobarbital (only in PC), 3-methylcholanthrene, isosafrole and Aroclor 1254, thus indicating that in rat liver the conversion of AFB1 to AFM1 is catalyzed by members of the cytochrome 1A and 2B families.

Animals↗
PubMed1986

Aflatoxins and kwashiorkor: clinical studies in Sudanese children.

Aflatoxin analysis of blood and urine by high performance liquid chromatography in 584 Sudanese children is reported. The results in 404 malnourished children comprising 141 kwashiorkor, 111 marasmic kwashiorkor and 152 with marasmus are compared with 180 age-matched controls and correlated with clinical findings. The aflatoxin detection rate and mean concentration were higher in serum of children with kwashiorkor than the other groups. The difference between the detection rate in kwashiorkor and controls was significant (p less than 0.05). The aflatoxin detection rate in urine was highest in the marasmic kwashiorkor group and the mean concentration was higher in the marasmic kwashiorkor and marasmic groups than in the kwashiorkor and control groups. There were important differences in the detection of certain aflatoxins between the groups. Aflatoxicol was detected in the sera of 16 (11.6%) kwashiorkor, in six (6.1%) marasmic kwashiorkor, but in none of the controls and only once in marasmus. These differences are highly significant (p less than 0.0001). The ratio of AFB1 to AFM1 was higher in the sera and urines of kwashiorkors than in controls, suggesting that the normal transformation of AFB1 to AFM1 may be impaired in kwashiorkor with consequent increase in transformation of AFB1 to aflatoxicol. The study therefore provides evidence of differences in the metabolism of aflatoxins in children with kwashiorkor compared with children with other forms of malnutrition and normally nourished children and confirms the association between aflatoxins and kwashiorkor contained in a preliminary report on this work.

Aflatoxin B1↗
PubMed1992

Modulation of aflatoxin B1 biotransformation in rabbit pulmonary and hepatic microsomes.

Aflatoxin B1 (AFB1) is a carcinogenic mycotoxin that requires activation to the corresponding 8,9-epoxide for activity. In addition to being present in foodstuffs, AFB1 can contaminate respirable grain dusts and thus the respiratory system is a potential target for carcinogenesis. In the present study, we have investigated the role of polycyclic aromatic hydrocarbon-inducible forms of cytochrome P-450 in the pulmonary and hepatic microsomal activation ([3H]AFB1-DNA binding) and detoxification ([3H]AFM1 and [3H]AFQ1 formation) of [3H]AFB1. In rabbit lung microsomes, the apparent Vmax for [3H]AFM1 formation was increased significantly when values were expressed per mg microsomal protein or per nmol P-450 present. In liver microsomes, the apparent Vmax for DNA binding and [3H]AFM1 formation were increased by beta-naphthoflavone (BNF) treatment (to 2.3 and 3.3 times control, respectively) when expressed per mg protein, but when expressed per nmol P-450, only AFM1 formation was significantly increased. The apparent Km values for both these reactions were unaffected. The apparent Vmax for [3H]AFQ1 formation was not affected by BNF treatment, but the apparent Km was increased to 4.5 times control. Boiling of microsomes or omitting the NADPH-generating system decreased DNA binding, AFM1 formation and AFQ1 formation by 89-97%, while addition of 1.0 mM SKF-525A inhibited these reactions by 46-57%. Addition of 1.0 mM alpha-naphthoflavone (ANF) had no effect on the biotransformation of [3H]AFB1 in lung microsomes of control rabbits, but significantly decreased AFM1 formation (by 31%) in lung microsomes from BNF-treated animals (other reactions were unaffected). In liver microsomes from BNF treated rabbits, 1.0 mM ANF inhibited DNA binding of [3H]AFB1 by 68%, while there was no effect in control microsomes. ANF significantly inhibited AFM1 formation in liver microsomes from both control and BNF-treated animals (by 87-97% and 67-78% at 1.0 mM and 2.0 microM, respectively), but had no effect on AFQ1 formation in liver microsomes from animals in either treatment group. These results indicate an important role for the 1A subclass of P-450 isozymes in the biotransformation of AFB1 to AFM1 in rabbit lung and liver, and a minor role in AFB1 activation in liver.

Aflatoxin B1↗
PubMed2006

Computer aided boar semen motility analysis for cereulide detection in different food matrices.

Computer Aided Semen Analysis (CASA) study of the boar semen motility has been demonstrated to be an appropriate assay for detection of cereulide (Bacillus cereus emetic toxin). Application of the boar semen bio-assay to detect cereulide directly in foods requires investigation of potential interference of food components, preservatives and other microbial and chemical food contaminants with the bio-assay. Current study provides evidence that none of included Staphylococcus aureus enterotoxins A, B, C and D nor B. cereus Hemolysin BL (HBL) and non-hemolytic enterotoxin (NHE) and three mycotoxins (Sterigmatocystin, Fumonisin B1 and Patulin) exhibited a toxic impact on semen progressive motility. Aflatoxin M1, M3 and zearalenone impaired semen motility only at concentrations (0.004 mg ml(-1), 0.1 mg ml(-1) and 10 mg ml(-1), respectively) much higher than those found in foods and those permitted by legislation, in comparison to cereulide which induces motility cease at concentrations lower than 20 ng ml(-1). Ten commonly used preservatives, namely potassium sorbate, sodium benzoate, (DL) malic acid, citric acid, (L+) tartaric acid, acetic acid, (DL) lactic acid, (L+) ascorbic acid, sodium chloride and sucrose induced no cease in spermatozoa motility even at preservative concentrations higher than permitted by legislation. Dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and acrylamide had no acute effect on spermatozoa motility at concentrations of 500 and 10,000 mg ml(-1), respectively. Robustness of computer aided boar semen motility analysis, tested with 14 different foods inoculated with cereulide producing B. cereus, showed distinct cereulide production in seven samples (although B. cereus growth to counts higher than 8 log CFU g(-1) was noted in 11 samples), in amounts close to those reported in foodborne outbreaks. Test evaluation in 33 samples suspected to hold cereulide showed actual cereulide presence in ten samples and no interference of food matrix with the assay.

Animals↗
PubMed1988

Universal immuno-stick test for direct rapid identification of microbial antigens within 5 minutes. Preliminary report.

Based on experiences with ELISA and biochemical fluorescence assays we have developed a new serologic identification system for detecting all conceivable particle and soluble antigens within 5 min using a very simple, sensitive procedure. This assay represents a sandwich ELISA that has been modified with regard to the sorbent, the enzyme substrate and the identification step. The test is performed as follows: 10 microliter aliquots of antigen dilution, specific or control antibody, respectively, and a phosphatase-conjugated anti-antibody are consecutively mixed. A small strip of special indicator sorbent paper (test stick) is moistened with this mixture for one minute. Subsequently it is dipped 3-5 times alternately in 0.1 M NaOH and a solution of the enzyme-substrate 4-methylumbelliferyl phosphate and immediately evaluated under a UV lamp. Positive samples instantaneously show brilliant light blue fluorescence and decolorization from dark red to white. Although the principle behind the reaction is not yet fully understood, the test works specifically and sensitively within a pg range. Thus far, for example, we have been able to identify Salmonella from suspended milk powder and streptococci from milk (3-5 cells/ml) without previous incubation, enterotoxins from staphylococcal colonies, Aflatoxin M1 and organ-phosphates. Results from examinations of staphylococcal enterotoxins are presented in more detail. Moreover, using a defined antigen, antibodies from different sera could be identified in the same rapid, sensitive and specific manner. Thus, we are convinced that the usual time-consuming enrichment methods for isolating pathogenic bacteria and other immunogenic substances as also current serologic assays will turn out to be superfluous.

Antigens, Bacterial↗
PubMed2003

Occurrence of aflatoxins M(1) and M(2) in milk commercialized in Ribeirão Preto-SP, Brazil.

Aflatoxins are toxic metabolites found in foods and feeds. When ruminants eat foodstuffs containing aflatoxins B(1) and B(2), these toxins are metabolized and excreted as aflatoxin M(1) and M(2) in milk. The aim was to determine the incidence of these aflatoxins in commercial milk collected from supermarkets in Ribeirão Preto-SP, Brazil, and consisting of 60 ultrahigh temperature (UHT) milk samples and 79 pasteurized milk samples. The milk samples were analysed according to method 986.16 of AOAC International. None of the milk samples analysed were contaminated with aflatoxin M(2), and aflatoxin M(1) was detected in 29 (20.9%) of samples in the range 50-240 ng l(-1). The results show that despite a high occurrence of aflatoxin M(1) in commercial pasteurized and UHT milk sold in Ribeirão Preto in 1999 and 2000, the contamination level of these toxins could not be considered a serious public health problem according to MERCOSUR Technical Regulations. However, levels in 20.9% of the milk samples exceeded the concentration of 50 ng l(-1) permitted by the European Union. Although it is not necessary to continue monitoring the incidence and levels of aflatoxins M(1) and M(2) in milk samples, surveillance could be appropriate.

Aflatoxin M1↗
PubMed2003

Aflatoxin residues in eggs of laying Japanese quail after long-term administration of rations containing low levels of aflatoxin B1.

The aim was to evaluate the excretion of residues of aflatoxin B(1) (AFB(1)), aflatoxin M(1) (AFM(1)), aflatoxin B(2a) (AFB(2a)) and aflatoxicol (AFL) in eggs of laying Japanese quail fed rations with low levels of aflatoxin B(1) for 90 days. The quail were randomly assigned into four experimental groups and given prepared rations containing either 0 (controls), 25, 50 or 100 microg AFB(1) kg(-1) feed. Thirty-two eggs per treatment were collected on days 1-7, 10, 20, 30, 60 and 90 of the aflatoxin treatment period, and submitted to aflatoxin analysis by high-performance liquid chromatography. Average egg production and feed consumption were not affected ( p > 0.05) by AFB(1). Egg weight was significantly lower ( p<0.05) only for groups exposed to 100 microg AFB(1) kg(-1). Residues of aflatoxins were detected in eggs at levels that ranged from 0.01 to 0.08 microg kg(-1) (AFB(1)), 0.03-0.37 microg kg(-1) (AFM(1)), 0.01-1.03 microg kg(-1)(AFB(2a)) and 0.01-0.03 microg kg(-1) (AFL). Results indicate that the excretion of aflatoxin residues in quail eggs might occur at relatively low concentrations under conditions of long-term exposure of quail to low levels of AFB(1).

Aflatoxin B1↗
PubMed2003

Aflatoxin B1 and its interconverting metabolite aflatoxicol in milk: the situation in Mexico.

Between 1996 and 1998, 580 litres of milk in Mexico were surveyed for aflatoxin B(1) (AFB(1)) and its metabolite aflatoxicol (AFL), which are mutagenic and carcinogenic mycotoxins that interconvert AFB(1)-AFL-AFB(1). The seven most consumed brands from different regions of Mexico included pasteurized and ultrapasteurized milk with four different fat levels: whole fat (28-33 g l(-1)), half-skimmed (10-20 g l(-1)), light (1-4 g l(-1)) and with vegetable oil (33 g l(-1)). Aflatoxins in each sample were concentrated with total aflatoxin immunoaffinity columns and quantitated by high-performance liquid chromatography. A milk sample was considered contaminated if it contained >/=0.05 microg l(-1) AFL. Pasteurization and ultrapasteurization of milk did not control contamination with AFL, which was present in 13% of samples at >/=0.05 microg l(-1) and in 8% at >/=0.5 microg l(-1), with a range of AFL from 0 to 12.4 microg l(-1). AFB(1) was present mainly in traces (0-0.4 microg l(-1)). The safest milk in relation to AFL contamination was imported milk powder with vegetable oil. There was a significant correlation between contamination of milk with AFL and the autumn (p<0.0002); the fat content was not significant.

Aflatoxin B1↗
PubMedDate not supplied

The 'carry-over' of aflatoxin into milk of cows fed ammoniated rations: use of an HPLC method and a genotoxicity test for determining milk safety.

Aflatoxin B1 (Af.B1) contaminated and detoxified commodities were used to feed lactating cows. The detoxification treatment was performed using an autoclaving process. Af.B1 contents in untreated groundnut meal, treated groundnut meal, and a mixture of treated groundnut meal and soyameal were 475.0, 6.0 and 3.0 micrograms/kg, respectively. Af.M1 determination in milk was performed using an HPLC method with a detection limit of 0.025 micrograms/l. Also, an attempt was made to apply a genotoxicity test, the SOS Chromotest, to check for the presence of genotoxic residues in the various milk samples. The total excreted Af.M1 was 1.08%, 14.7% and 6.35% of the total ingested Af.B1 from untreated, treated and mixed treated feed, respectively. An unusual Af.M1 excretion peak was observed during the first four days of feeding the treated diet. Approximately 30% of the unreacted ingested Af.B1 appeared in the milk as the metabolite Af.M1. On the following days, the amount of Af.M1 in the milk samples decreased quickly and became almost undetectable. However, the genotoxicity test assays did not show any difference between the various experimental milk samples.

Aflatoxin B1↗
PubMedDate not supplied

Effects of ammoniation on the 'carry-over' of aflatoxins into bovine milk.

Two experiments were performed using lactating cows fed various treated and non-treated commodities from AFB1 contaminated peanut cakes. Treatment with ammonia gas by an autoclaving process was used for detoxification. Two methods were used for AFM1 determination in every milk sample: a TLC procedure recognized by AOAC and IDF and an HPLC method with a detection limit of 0.100 and 0.010 microgram/l, respectively. In a first experiment, lactating cows were fed treated and untreated meals during periods separated by uncontaminated soya meals phases. The total excreted AFM1 was 2.6% of the total ingested AFB1 from untreated feed contaminated at 1100 micrograms/kg. During periods receiving treated meals in the diet, AFM1 contents in milk were below 0.1 microgram/l. However, by using AFM1 data obtained using the HPLC method, an AFM1/AFB1 ratio of 4.6% was found from treated feed contaminated at 40 micrograms AFB1/kg. In a second experiment, a herd of 50 lactating cows was used for a long term (16 months) feeding of mixed commodities containing 30% ammoniated peanut cakes. AFB1 residues in the treated diet were below 10 micrograms/kg, the EEC action level, and no AFM1 residue was found up to 0.1 microgram/l in collected milk throughout this experiment.

Aflatoxin B1↗
PubMed1993

Inhibition of dexamethasone-induced cytochrome P450-mediated mutagenicity and metabolism of aflatoxin B1 by Chinese medicinal herbs.

Oldenlandia diffusa (OD) and Scutellaria barbata (SB) have been used in traditional Chinese medicine for treating liver, lung and rectal tumours. We previously showed that they inhibited mutagenesis, DNA binding and metabolism of aflatoxin B1 (AFB1) and benzo(a)pyrene (BaP) bioactivated by Aroclor 1254-induced rat S9. The purpose of this study was to investigate the effects of OD and SB on the mutagenicity of AFB1 in Salmonella typhimurium TA100 using dexamethasone (DXM)-induced rat hepatic S9, on cytochrome P450-linked aminopyrine N-demethylase (APND) activity in DXM-induced hepatic microsomes and on the metabolism of AFB1 by DXM-induced S9 using high-performance liquid chromatography (HPLC). The experimental results showed that OD and SB consistently inhibited the mutagenicity of AFB1 bioactivated by either non-induced or DXM-induced S9. These effects correlated with the inhibition of cytochrome P450-linked APND activity in DXM-induced microsomes and with an inhibition of DXM-induced S9 mediated metabolism of [3H]AFB1 as determined by HPLC. Since DXM treatment has been associated with an induction of the CYP3 enzyme family, these results suggest that OD and SB may possess antimutagenic and antitumorigenic activity towards AFB1 through an inhibition of CYP3-mediated metabolism of AFB1.

Aflatoxin B1↗
PubMed1990

Biological reactive intermediates of bisfuranoid mycotoxins.

Based on the mode of action of AFB1 and the activities of its biologically active intermediates, one may conclude that: 1. The mode of toxic action of the bisfuranoid mycotoxin is through epoxidation of the vinyl ether double bond of their dihydrobisfuran functionality. 2. The DNA and plasma albumin adducts formed in vivo may be useful in the molecular dosimetry of these environmental carcinogens. 3. Monitoring of these adducts of AFB1 in biological samples so far indicates that aflatoxin is likely involved in the etiology of human liver cancer.

Aflatoxin B1↗
PubMed1999

Toxic effects of mycotoxins in humans.

Mycotoxicoses are diseases caused by mycotoxins, i.e. secondary metabolites of moulds. Although they occur more frequently in areas with a hot and humid climate, favourable for the growth of moulds, they can also be found in temperate zones. Exposure to mycotoxins is mostly by ingestion, but also occurs by the dermal and inhalation routes. Mycotoxicoses often remain unrecognized by medical professionals, except when large numbers of people are involved. The present article reviews outbreaks of mycotoxicoses where the mycotoxic etiology of the disease is supported by mycotoxin analysis or identification of mycotoxin-producing fungi. Epidemiological, clinical and histological findings (when available) in outbreaks of mycotoxicoses resulting from exposure to aflatoxins, ergot, trichothecenes, ochratoxins, 3-nitropropionic acid, zearalenone and fumonisins are discussed.

Adult↗
PubMed2002

Evaluation of certain mycotoxins in food. Fifty-sixth report of the Joint FAO/WHO Expert Committee on Food Additives.

This report presents the conclusions of a Joint FAO/WHO Expert Committee convened to assess the risks associated with the consumption of food contaminated with certain mycotoxins. The first part of the report contains a general discussion of the principles for evaluating mycotoxins in food, including those concerning analytical methods, sampling, data on food consumption and dietary intake, and prevention and control. The second part provides a summary of the Committee's evaluations of toxicological data on specific mycotoxins, including aflatoxin M1, fumonisins B1, B2 and B3, ochratoxin A, deoxynivalenol, and T-2 and HT-2 toxins.

Food Contamination↗
PubMed2003

[Effects of animal housing facilities on residues and contaminants in food].

There are--especially in the case of food of animal origin--only a few well-controlled studies available comparing organically and conventionally produced food with a focus on residues and contaminants. The differences found seemed to be much lower than expected, and the amounts of residues and contaminants were mostly below regulatory maximum residue levels. In the case of organically and conventionally produced milk there have been slight but usually not significant differences reported. One important observation is, that conventionally produced milk contains aflatoxin M1 more frequently than biologically produced milk. The investigation of eggs from different housing systems for laying hens showed in the case of dioxins the highest concentrations in free range eggs. In contrast, propoxur, an insecticide used against the poultry red mite, was found in eggs from battery cages in higher amounts than in those from enriched cages and in eggs obtained from an aviary system. Further research in this field is highly recommended, but there should be more sophisticated evaluation of the data sets from national and international monitoring programs.

Agriculture↗