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PubMed2002

Acrylamide from Maillard reaction products.

The discovery of the adventitious formation of the potential cancer-causing agent acrylamide in a variety of foods during cooking has raised much concern, but the chemical mechanism(s) governing its production are unclear. Here we show that acrylamide can be released by the thermal treatment of certain amino acids (asparagine, for example), particularly in combination with reducing sugars, and of early Maillard reaction products (N-glycosides). Our findings indicate that the Maillard-driven generation of flavour and colour in thermally processed foods can -- under particular conditions -- be linked to the formation of acrylamide.

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PubMed2003

Beta-lactams or gamma-lactams by 4-exo-trig or 5-endo-trig anionic cyclisation of lithiated acrylamide derivatives.

Substituted acrylamide derivatives of benzylamine are lithiated alpha to nitrogen by LDA. The benzyllithium thus formed undergoes either 5-endo-trig anionic cyclisation, formally by intramolecular conjugate addition to the acrylamide, to yield 5-membered lactams, or, if the acrylamide bears a beta-electron withdrawing group, 4-exo-trig cyclisation to a beta-lactam.

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PubMed2006

Sensitive isotope dilution liquid chromatography/electrospray ionization tandem mass spectrometry method for the determination of acrylamide in chocolate.

Isotope dilution liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-MS/MS) was applied to the quantification of acrylamide in chocolate matrixes (dark chocolate, milk chocolate, chocolate with nuts, chocolate with almonds, and chocolate with wheat best element). The method included defatting with petroleum ether, extracting with aqueous solution of 2 mol l(-1) sodium chloride and clean-up by solid-phase (SPE) with OASIS HLB 6 cm3 cartridges. Acrylamide was detected with an Atlantis dC18 5 microm 210 x 1.5 mm column using 10% methanol/0.1% formic acid in water as the mobile phase. The analytical method was in-house validated and good results were obtained with respect to repeatability (RSD < 3.5%) and recovery (86-93%), which fulfilled the requirements defined by European Union legislation. The acrylamide levels in chocolate were 23-537 microg kg(-1). Therefore, the method was successfully used for the quantitative analysis of acrlyamide in various chocolate products.

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PubMedDate not supplied

Determination of acrylamide in sugar by capillary GLC with alkali flame-ionization detection.

A method for the determination of acrylamide traces as a residue of anti-incrustation agents in sugar was developed. Acrylamide was extracted into ethyl acetate after derivatization by bromination to 2,3-dibromopropionamide (2,3-DBPA). The extract was cleaned up on a silica gel column and analysed by gas-liquid chromatography with an alkali flame-ionization detector (AFID). A glass capillary column with OV-1 stationary phase was used for this analysis. The recovery of the method determined in model experiments was 70.0% and 77.1% at 100 micrograms kg-1 and 20 micrograms kg-1, respectively. The limit of detection of acrylamide in sugar is 1-10 micrograms kg-1. Parameters of the described method are compared with other published methods.

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PubMed2006

Universal behaviour of gel formation from acrylamide-carrageenan mixture around the gel point: a fluorescence study.

The steady state fluorescence (SSF) technique was used to study the sol-gel transition, for the solution free radical crosslinking copolymerization of acrylamide (AAm) with various carrageenan content. N, N'- methylenebis (acrylamide) (BIS) and ammonium persulfate (APS) are used as crosslinker and an initiator, respectively. Pyranine (8-hydroxypyrene-1, 3,6-trisulfonic acid, trisodium salt, HPTS) was added as a floroprobe for monitoring the polymerization. Pyranine molecules start to bind to acrylamide polymer chains upon the initiation of the polymerization; thus, the spectra of the bonded pyranines shift to the shorter wavelengths. Fluorescence spectra from the bonded pyranines allows one to monitor the sol-gel transition, without disturbing the system mechanically, and to test the universality of the sol-gel transition as a function of some kinetic parameters like polymer concentration. Observations around the critical point show that the gel fraction exponent beta obeyed the percolation result for low carrageenan concentrations (< 2.0%) however classical results were produced at higher carrageenan concentration (> 2.0%).

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PubMedDate not supplied

Electrospray ionization mass spectrometric characterization of acrylamide adducts to hemoglobin.

The most common procedure to identify hemoglobin adducts has been to cleave the adducts from the protein and characterize the adducting species, by, for example, derivatization and gas chromatography/mass spectrometry. To extend these approaches we used electrospray ionization mass spectrometry (ESI-MS) to characterize adducted hemoglobin. For this we incubated [14C]acrylamide with the purified human hemoglobin (type A0) under conditions that yielded high adduct levels. When the hemoglobin was separated by reversed-phase high-performance liquid chromatography (HPLC), 65% of the radioactivity copurified with the beta-subunit. Three adducted species were prominent in the ESI mass spectrum of the intact beta-subunit, indicating acrylamide adduction (i.e., mass increase of 71 Da) and two additional unidentified moieties with mass increments of 102 and 135 Da. Endoproteinase Glu-C digestion of the adducted beta-subunit resulted in a peptide mixture that, upon reversed-phase HPLC separation, provided several radiolabeled peptides. Using ESI-MS we identified these as the V91-101 and V102-122 peptides that represent the cysteine-containing peptides of the beta-subunit. These results provide definitive information on acrylamide-modified human hemoglobin and demonstrate that ESI-MS provides valuable structural information on chemically adducted proteins.

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PubMed1975

Physiological studies of the dying-back phenomenon. Muscle stretch afferents in acrylamide neuropathy.

(1) The responses of 1,001 medial gastrocnemius afferents with conduction velocities of 24-126 m/sec have been studied in cats with experimental acrylamide neuropathy. (2) Many units which conducted at velocities indicating that they innervated muscle stretch receptors failed to discharge during muscle stretch or contraction. In animals with mild neuropathy 10 per cent of 366 units were non-responsive. In animals with moderate or severe neuropathy the proportion of non-responsive units was 68 per cent of 315 fibres and 89 per cent of 320 fibres respectively. Group I fibres were involved to a greater extent than Group II fibres. (3) The distributions of identified functioning units with respect to conduction velocity were normal, indicating that acrylamide did not produce conduction slowing before failure of function. (4) Electrophysiological and histological findings indicate that acrylamide initially produces failure of impluse conduction and subsequent fibre breakdown in the terminal axon while normal impulse conduction is preserved more proximally.

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PubMed1999

Determination of acrylamide monomer in polyacrylamide degradation studies by high-performance liquid chromatography.

A high-performance liquid chromatography method using C18 and ion-exchange columns in series is developed for the determination of acrylamide and acrylic acid monomers in polymeric samples. The C18 column acts as a guard column, trapping surfactants and impurities and retaining the nonionic species. The ion-exchange column then separates the monomers according to their respective ionic strengths. This method has been proven in the laboratory to work successfully for all types of acrylamide/acrylic acid polymers and matrices. Detection limits for both monomers can be achieved in the parts-per-billion range. The method is used to study the possible degradation of polyacrylamide to acrylamide monomer in the presence of glyphosate (a herbicide) and sunlight. Polyacrylamide is used as a spray drift reduction aid in combination with glyphosate. In normal applications, the polymer and herbicide are in contact with each other in the presence of sunlight. The results show that the polymer does not degrade to acrylamide in the presence of glyphosate or sunlight or any combination of the two. It is also observed that glyphosate influences the solubility of polyacrylamide, and care must be used when combining the two.

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PubMed1999

Detection of aneuploidy by multicolor FISH in mouse sperm after in vivo treatment with acrylamide, colchicine, diazepam or thiabendazole.

Multicolor fluorescence in situ hybridization (FISH) was used to investigate the induction of aneuploidy during meiosis in young adult male mice treated with chemicals chosen for the EU sponsored aneuploidy project (acrylamide, colchicine, diazepam and thiabendazole). The aim of the present study was to evaluate the frequency of aneuploid sperm induced by each of these chemicals by sperm FISH. Male (102/ElxC3H/El)F1 mice were treated with acrylamide (120 and 60 mg/kg single dose i.p.), colchicine (1.5 and 3 mg/kg single dose, i.p.), diazepam (300, 150 and 75 mg/kg single dose by oral intubation) or thiabendazole (100 and 300 mg/kg daily for 11 days by oral intubation). At 22 days after the last treatment, sperm were collected from the cauda epididymis. Three chromosome FISH was applied to determine hyperhaploid and diploid sperm with DNA probes specific for the chromosomes X, Y and 8. Five animals were treated per dose group and sperm aneuploidy was evaluated in 10,000 sperm per animal. We found significant increases in the frequency of total hyperhaploidy for the males treated with 3.0 mg/kg colchicine (0.092 versus 0.056%, P < 0.05) and with 1.5 mg/kg colchicine (0.082 versus 0.050%, P < 0.05), as well for the males treated with 300 mg/kg diazepam (0.081 versus 0.050%, P < 0.05), indicating that colchicine and diazepam each induced germ cell aneuploidy. We also found significant increases in the frequency of total diploidy for the males treated with 300 mg/kg diazepam (P < 0.05) and with 300 mg/kg thiabendazole (P < 0.05). No significant effects were found for 120 and 60 mg/kg acrylamide or for the other doses of diazepam and thiabendazole. These first results indicate that the multicolor FISH method is useful to determine aneuploidy induction in sperm of mice.

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PubMed1999

Immobilization of acrylamide-modified oligonucleotides by co-polymerization.

A flexible chemistry for solid phase attachment of oligonucleotides is described. Oligonucleotides bearing 5'-terminal acrylamide modifications efficiently co-polymerize with acrylamide monomers to form thermally stable DNA-containing polyacrylamide co-polymers. Co-polymerization attachment is specific for the terminal acrylamide group. Stable probe-containing layers are easily fabricated on supports bearing exposed acrylic groups, including plastic microtiter plates and silanized glass. Attachment can be accomplished using standard polyacrylamide gel recipes and polymerization techniques. Supports having a high surface density of hybridizable oligonucleotide (approximately 200 fmol/mm2) can be produced.

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PubMed1999

Changes in thyroid gland morphology after acute acrylamide exposure.

High exposure to the acrylamide monomer has been associated with neuropathy and neurotoxic effects. Chronic lower exposure causes endocrine disruption associated with thyroid, testicular, and mammary tumors. To investigate mechanisms of endocrine disruption, short-term, low-level oral dosing studies were conducted. Weanling female Fischer 344 rats were acclimatized for two weeks before dosing. Controls were given distilled water by gavage and rats in other groups were given acrylamide at doses of 2 mg/kg/day and 15 mg/kg/day for 2 or 7 days by gavage. Twenty-four h after the last dose, the rats were killed by decapitation. Trunk blood was collected for hormone analyses and tissues for histopathological examination. There were no toxicity-related deaths, no clinical signs of toxicity, and no significant difference in the mean body weight of animal groups. Histopathological examination of select tissues showed no lesions of pathologic significance. Plasma thyroxine (T4), thyroid stimulating hormone (TSH), prolactin (PRL), and pituitary TSH and PRL analyses did not reveal significant changes between control vs. treated rats. In the 7-day study, however, there was a slight dose-dependent increase in plasma T4 and a slight dose-dependent decrease in plasma TSH. Thyroid gland morphometry showed a significant (p < 0.05) decrease in the colloid area and a significant increase (p < 0.05) in the follicular cell height of treated rats as compared to controls. The follicular area shrinkage was similar in both studies. These results show a very early endocrine response to very low levels of toxic insult and opens other venues to further investigate the mechanisms of endocrine disruption by acrylamide.

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PubMed1998

Studies on nonpeptide angiotensin II receptor antagonists. IV. Synthesis and biological evaluation of 4-acrylamide-1H-imidazole derivatives.

A novel series of nonpeptide angiotensin II antagonists containing the acrylamide group at the 4-position of the imidazole ring was synthesized and their antagonistic activity was examined by functional assay in rabbit aorta. The acrylamide group was selected as a large lipophilic surrogate for the chloro group of EXP3174. A structure-activity relationship study of the acrylamide moiety has shown that substitution at the 4-position with the N-methyl-3,3-dimethylacrylamide group resulted in the optimal compound, 2-butyl-4-[(3,3-dimethylacryloyl)methyl-amino]-1-[[2'-(1H-tetra zol-5- yl)biphenyl-4-yl]methyl]-1H-imidazole-5-carboxylic acid (1), which was superior to EXP3174 in vitro. Since 1 showed only poor activity against angiotensin II-induced pressor response in rats after oral administration, the carboxylic acid function of 1 was converted into prodrug esters (13). Among these, the 1-[(ethoxycarbonyl)oxy]ethyl ester (13a) showed the most potent and longest-lasting activity when given orally to rats. When administered orally to conscious furosemide-treated dogs, 13a showed an approximately 3-fold increased hypotensive activity in comparison with DuP 753. These data suggest that 13a may be an useful agent for the treatment of angiotensin II-dependent diseases, such as hypertension.

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PubMed2002

Acrylamide capture of DNA-bound complexes: electrophoretic purification of transcription factors.

We have developed a rapid nonradioactive electrophoretic technique to analyze proteins within DNA-binding complexes, acrylamide capture of DNA-binding complexes (ACDC), using Acrydite-linked DNA-binding targets. The method is highly sensitive and easily adaptable to virtually any protein-DNA interaction. The utility of this technique is illustrated using recombinant and full-length androgen receptors and associated co-regulatory proteins present within nuclear extracts. In brief proteins were incubated with DNA-binding targets in which one oligonucleotide was synthesized with an Acrydite moiety at the 5' end to allow for covalent linkage to acrylamide. Alternatively, gene promoter regions were amplified with an Acrydite-modified PCR primer to analyze protein-DNA complexes. The DNA-binding reaction was polymerized into an acrylamide matrix within the well of a precast gel. Proteins complexed to the Acrydite DNA are trapped and purified by the electrophoretic migration of unbound proteins. Proteins captured in the Acrydite-DNA can be eluted and identified by Western analysis or 2-D gel electrophoresis. The advantages of this technique are that it is rapid, adaptable, sensitive, unlimited by the size of the DNA or protein complex, and can be used to detect tertiary interactions with co-regulatory factors and unidentified proteins. These features make the ACDC technique a powerful tool for transcription factor research.

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PubMed2000

Induction of micronuclei in bone marrow and sperm head abnormalities after combined exposure of mice to low doses of X-rays and acrylamide.

People come into contact with chemical and physical agents which are present in the environment and in workplaces. We investigated the effects of combined exposures to low doses of X-rays (0.05-0.25 Gy) and acrylamide (AA; 75 mg/kg bw) in the somatic and germ cells of outbred male mice by using a bone-marrow micronucleus test and a sperm morphology test. Combined treatment of germ cells to 0.25 Gy of X-rays + 75 mg/kg bw of acrylamide enhanced the effect induced by each agent given alone. The results confirmed the sensitivity to damage of spermatozoa and late spermatids, which can be demonstrated by sperm head abnormalities and reduced fertility. The sensitivity of somatic cells to acrylamide alone was similar to that of germ cells. Combined exposure to 0.05 Gy + 75 mg/kg bw of AA induced micronuclei in polychromatic erythrocytes of bone marrow although each dose did not produce a mutagenic effect. Teratogenesis Carcinog. Mutagen. 20:133-140, 2000.

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PubMedDate not supplied

[Participation of the cytochrome P450-dependent biotransformation system in realizing the toxic effects of acrylamide].

Neuro-, hepato- and geno-toxic effects of the industrial xenobiotic, acrylamide, were studied in intact rats and in rats with induced phenobarbital- and 3-methylholanthren-dependent isoforms of cytochrome P-450. The induction of the first isoform increased neuro- and hepato-toxic effects of acrylamide and decreased the extent of cell genome damage. Activation of the 3-methylholanthren-dependent cytochrome had no influence on the toxicity of this xenobiotic. Realisation of toxic effects of acrylamide may involve a decrease of the carbohydrate energy metabolism, but in the intact organism these processes precede the induction of the phenobarbital-dependent cytochrome P450.

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PubMedDate not supplied

[Hydrodynamic properties of exopolysaccharide-acrylamide copolymer].

The method for producing copolymer EPAA of exopolysaccharide (EPS)--polyacrylamide (PAA) has been presented which was based on microbial exopolysaccharides (enposane, xampane), their mixture and model EPS (xanthane sigma, rodopol P-23). The copolymer was produced by acrylamide polymerization in 1-2% water solutions of polysaccharides, the concentration of acrylamide in the reaction mixture being 4.7-2% and that of polysaccharides 0.1-1% of the weight. Hydrodynamic parameters of the studied polymers have been determined, their heterogenity as to molecular-weight characteristics has been demonstrated. Molecular-weight distribution of copolymers showed that the content of low-molecular fractions decreased, thus the Mw values were (0.08-0.2) x 10(6) Da in contrast to that of exopolysaccharides possessing Mw (1.2-0.4) x 10(6) Da and of polyacrylamide possessing Mw within (2-30) x 10(6) Da. The value of efficient viscosity of copolymers ranged from 120 to 131 mPa.s that was lower than that of polyacrylamide (500 mPa.s), and higher than that of exopolysaccharides (42 mPa.s), and it depended on the sample, raw material, production conditions. A possibility has been shown to produce a new copolymer based on microbial polysaccharides enposane and xampane in the process of acrylamide polymerization. It has been found out that the studied copolymers EPAA differ from initial ones as to their hydrodynamical properties, which determines their preference: better solubility, good glueing properties, prolonged term of preservation, resistance to bacterial pollution.

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PubMedDate not supplied

Assessment of performance of laboratories in determining acrylamide in crispbread.

A proficiency testing round was undertaken to assess the performance of laboratories to measure acrylamide in a sample of crispbread. Retail samples of crispbread were ground to a fine powder and after thorough mixing were packed in 40 g units for distribution. Ten samples were selected at random and analyzed in duplicate for acrylamide by liquid chromatography/mass spectrometry (LC/MS). Standard statistical tests showed that the material was homogeneous for the purposes of proficiency testing. Test samples were distributed to 55 laboratories in 16 countries in Europe, North America, Australia, and the Middle East. The results were analyzed by standard proficiency testing statistical procedures, and laboratories were awarded z-scores on the basis of their reported results. Based on a target standard deviation (sigmap value) taken from the Horwitz equation, for a robust mean value of 1.2 mg/kg acrylamide, satisfactory results (z-score within +/- 2 for those between 0.8 and 1.6 mg/kg) were obtained by 86% of the 37 laboratories that returned results. Only 1 laboratory was unsatisfactory and 4 had questionable results. About equal numbers of laboratories used gas chromatography (GC)/MS and LC/MS procedures with about 25% using MS/MS and one using GC with electron capture detection. There was no evident trend in performance or bias in results. GC/MS and LC/MS data were evenly distributed across the population of laboratories reporting results.

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PubMedDate not supplied

Solid-phase extraction and cleanup procedures for determination of acrylamide in fried potato products by liquid chromatography/mass spectrometry.

In response to recent discoveries of acrylamide in heated foods, a solid-phase extraction and cleanup protocol was developed for the determination of acrylamide in fried or baked potato samples by liquid chromatography/mass spectrometry (LC/MS). The analyte was extracted from the matrix by using 2M NaCl, and an aliquot of the initial extract was loaded onto a reversed-phase cartridge. After the analyte was eluted from the cartridge, the eluate was cleaned up on a mixed-mode cation-exchange cartridge. The eluate was then evaporated, and the residue was reconstituted in mobile phase before LC/MS analysis. Recoveries, based on the recovery of an added internal standard, ranged from 96 to 101% with relative standard deviations (RSDs) of 5-11%. The response was linear for a concentration range of 100-2000 ng/g with a coefficient of determination (R2) of 0.992 (n = 25). An interday study showed good accuracy and precision of the method over a 3-day period with a recovery of 98% and an RSD of 9.5% (n = 15). The analyses of 6 potato chip samples showed concentrations of incurred acrylamide ranging from 260 to 1500 ng/g.

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