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PubMed1995

Formation of N-7-(2-carbamoyl-2-hydroxyethyl)guanine in DNA of the mouse and the rat following intraperitoneal administration of [14C]acrylamide.

Acrylamide is an alkylating agent which reacts very slowly in direct reactions with DNA and is negative in the Ames test, but is carcinogenic in mice and rats. In order to explain the cancer-initiating properties of acrylamide we have studied DNA adduct formation in vitro with a metabolizing system and in vivo in mice and rats following i.p. administration of 14C-labeled acrylamide. A major adduct found in both species was N-7-(2-carbamoyl-2-hydroxy-ethyl)guanine, formed by reaction of the DNA with the epoxide metabolite glycidamide. The levels of this adduct were similar in the different organs of the two rodent species, which supports the notion that glycidamide is relatively evenly distributed among tissues and that the organ-specificity in acrylamide carcinogenesis cannot be explained by a selective accumulation of the DNA-reactive metabolite in target organs.

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PubMed1983

Carcinogen-mediated induction of SV40 DNA amplification is enhanced by acrylamide in Chinese hamster CO60 cells.

The exposure of SV40-transformed Chinese hamster cells (line CO60) to 50-150 micrograms/ml of monomeric acrylamide for 24 h resulted in a very weak induction of the amplification of the SV40 DNA inserts as measured by in situ hybridization with radioactive SV40 DNA as probe. The weak SV40 DNA amplification observed might result from a weak DNA-damaging activity as biologically illustrated by the capacity of high concentrations of acrylamide to irreversibly inhibit the DNA synthesis rate of CO60 cells. Moreover, acrylamide synergistically enhanced both the cytotoxicity and the induction of SV40 DNA synthesis by the carcinogens ethylmethane sulfonate, benzo[a]pyrene, mitomycin C, 4-nitroquinoline-1-oxide, 8-azaguanine and 5-fluorodeoxyuridine. Although a weak inducer of SV40 DNA amplification by itself, acrylamide potentiated the genotoxicity of a series of chemical carcinogens. This finding should be taken into consideration when assessing the risk of this widely used chemical.

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PubMed1989

Mortality patterns among workers exposed to acrylamide.

A cohort of 8854 men, 2293 of whom were exposed to acrylamide, was examined from 1925 to 1983 for mortality. This cohort consisted of four plant populations in two countries: the United States and The Netherlands. No statistically significant excess of all-cause or cause-specific mortality was found among acrylamide workers. Analysis by acrylamide exposure levels showed no trend of increased risk of mortality from several cancer sites. These results do not support the hypothesis that acrylamide is a human carcinogen.

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PubMed1994

Interaction of tryptophan residues of cytochrome P450scc with a highly specific fluorescence quencher, a substrate analogue, compared to acrylamide and iodide.

The cytochrome P450scc tryptophan fluorescence was studied by the use of the three quenchers acrylamide, 25-doxyl-27-nor-cholesterol (CNO) and potassium iodide (KI). All the nine tryptophan residues were accessible to acrylamide. Whereas a strong interaction (static quenching) between acrylamide and tryptophan in the active site had been found previously for cytochrome P450c21 [Narasimhulu, S. (1988) Biochemistry 27, 1147-1153], in the case of P450scc the temperature dependence of the slope of the linear Stern-Volmer plots indicated a dynamic quenching mechanism. This mechanism was confirmed by fluorescence lifetime measurements. Of the three observed life-times tau 1 = 3.1 +/- 0.5 ns, tau 2 = 0.7 +/- 0.25 ns and tau 3 = 20 +/- 10 ps, tau 1 decreased noticeably as a function of the acrylamide concentration. CNO, a spin-labeled substrate which is known to bind tightly to the substrate-binding site of P450scc, quenched 15.5% of the total fluorescence. The Lehrer plot of this compound indicated a static quenching process with a reciprocal quenching constant of 1/Ks = 4 microM, a value which is in accord with the dissociation constant. Our data indicate that CNO quenches selectively one or two tryptophan residue(s) in the active site. The fluorescence spectrum of the residue(s) accessible to CNO was characterized by a red-shifted emission maximum (from 332 nm to 336 nm). The same residue(s) appeared to be quenched by potassium iodide, although much less effectively (1/Ks = 0.12 M). The most probable candidate for a complex formation with CNO is Trp417, which is rather close to Cys422 (the fifth heme ligand). Four arginine residues (Arg411, Arg420, Arg425 and Arg426) in the heme peptide may constitute the iodide-binding site.

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PubMed1983

Early and dose-dependent decrease of retrograde axonal transport in acrylamide-intoxicated rats.

The effect of retrograde axonal transport of doses of acrylamide ranging from 50 to 500 mg/kg was studied in sensory nerve of rats. Accumulation of trichloroacetic acid-phosphotungstic acid-insoluble label was measured in a collection segment distal to a double ligature placed on the sciatic nerve at intervals 9-15 h and 9-24 h following injection into the dorsal root ganglion of the fifth lumbar root of [35S]methionine and [3H]fucose. After a dose of 100 mg/kg of acrylamide no neurological signs of neuropathy had yet appeared, but retrograde buildup of protein label was significantly reduced for the long interval (2.20 +/- 0.49 arbitrary units (AU) (mean +/- SD) versus 2.81 +/- 0.57 AU in controls, 2p = 0.034). No abnormality of the short interval appeared before a dose of 500 mg/kg was reached. The retrograde transport abnormality was dose-related (r = -0.85, n = 28, and 2p = 1.2 x 10(-8)), as was the degree of neuropathy evaluated by "blind" neurological scoring (r = 0.88, n = 14, and 2p = 2.8 x 10(-5)). After a dose of 500 mg/kg, when the rats were severely disabled with almost total incoordination of the hindlegs, the retrograde accumulation of the long interval was profoundly depressed (1.08 +/- 0.28 AU versus 2.81 +/- 0.57 AU in controls, 2p = 1.2 x 10(-7)). Similar changes were seen in accumulation of glycoprotein label. After the rats had recovered for 4-10 weeks neurological signs of neuropathy had disappeared and the transport abnormality had improved. To test the specificity of acrylamide on the retrograde transport defect N-hydroxymethylacrylamide and methylene-bisacrylamide, which do not induce neuropathy, were studied. None of these related compounds influenced the transport. These observations imply that in acrylamide intoxication a defect in the amount of material carried by retrograde axonal transport rather than in "turnaround" time or in transport velocity is present, that the transport abnormality precedes the development of neuropathy, and that it is related to the degree of the neurological disability. We suggest that the retention of protein in the distal axons in the functional counterpart of the well-known accumulation of vesicular organelles in the preterminals.

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PubMed1991

Electronic states of the indole-acrylamide molecular pair.

A model is suggested for tryptophan fluorescence quenching by acrylamide based on the prediction that acrylamide can absorb a photon from the excited indole moiety and then dissipate the optical energy into a sink of fast exchanging conformations. Semiempirical electronic structure calculations of the indole-acrylamide pair indicate little actual intermolecular orbital mixing at van der Waals contact distances. However, the two lowest singlet transitions of the molecular pair, assigned to the acrylamide (pi *)----n(O) line and to the indole 1Lb----1A1 line, respectively, vary significantly in energies and in transition and excited state moments with the geometry of interaction between the two entities. The distribution of optimal quenching coordinations depends separately on the benzene and pyrrole portions and has a distinctly non-spherical shape at these distances.

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PubMed1992

Acrylamide quenching of the fluorescence of glyceraldehyde-3-phosphate dehydrogenase: reversible and irreversible effects.

The acrylamide quenching of the tryptophan fluorescence of apo and holo glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was studied. In the case of apo-GAPDH, the steady state fluorescence quenching cannot be described by the classical Stern-Volmer equation: strong cooperative quenching is observed. In the presence of Pi and/or cofactor NAD+, an inaccessible fraction appears. Cooperative quenching is partially suppressed in the presence of Pi and fully absent in the presence of NAD+. The measurements of the fluorescence lifetimes of the holo-enzyme by phasefluorometry allow the resolution of two lifetimes. The long-lived component is quenched by acrylamide, the short-lived component is not. Quenching induces a red shift of the steady state emission peak. The quenching parameters from the lifetime measurements allow the quantitative description of the steady state fluorescence quenching data. In agreement with the observations of Orstan and Gafni (Photochemistry and Photobiology, (1990) 31, 725-731), we find that acrylamide causes a slow, irreversible loss of activity and a reduction of titratable thiol groups when it acts on the apo-enzyme. This inactivation is strongly reduced in the presence of NAD+. We show that this inactivation is also slowed down by the presence of Pi, and that it is accompanied by a loss of the NAD+ binding site. Blocking the thiol groups with 5,5'-dithio-bis-(2-nitrobenzoic acid) does not lead to a protection against the irreversible inactivation by acrylamide, showing that reactions other than thiol modifications are involved in the irreversible effect. A fraction of the inactivation can be reversed by treatment with mercapto-ethanol.

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PubMed1985

Reversible abnormalities of the Hering Breuer reflex in acrylamide neuropathy.

The sensitivity of the Hering Breuer reflex was compared in anaesthetised rabbits before, during and after the induction of acrylamide neuropathy, and was measured as the tracheal pressure which produced 30 seconds of apnoea. After four weeks of acrylamide (400 mg/kg total dose) there was ataxia and the conduction velocity of hindlimb motor nerves was significantly reduced. At this time there was a marked and reproducible reduction in the sensitivity of the Hering Breuer reflex. The ataxia resolved within a month of stopping acrylamide administration. Three months after the cessation of acrylamide the sensitivity of the Hering Breuer reflex had increased significantly but had not returned to normal.

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PubMed1991

Novel applications of acrylamide for cryosectioning of isolated cells, tissues, and arthropods.

Cross-linked and uncross-linked acrylamide polymers were used to alleviate technical difficulties in cryosectioning and autoradiographic processing of marine arthropods (Pycnogonum litorale), larval insect tissues (Sarcophaga bullata), and amphibian (Xenopus laevis) oocytes. Rapidly polymerized cross-linked acrylamide was used to prepare sections from an animal with a hard thick cuticle, P. litorale. Fragmentation and compression artifacts caused by tissue density differences were avoided and internal tissues were well preserved. Our results indicate that closely applied external support eliminates difficulties typically associated with arthropod cryosectioning. Pre-polymerized, uncross-linked acrylamide provided similar protection when used for sectioning larval tissue from S. bullata. Soft tissues under the cuticle were undamaged in tracheal and epidermal preparations. This polymer was also an excellent embedding material for soft tissues such as salivary glands, quickly penetrating tissue cavities and eliminating air bubbles. Uncross-linked acrylamide was used as an embedding and culturing medium for oocytes from X. laevis. The polymers were non-toxic and allowed the preparation of thin frozen sections containing as many as 50 large oocytes per section.

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PubMed1984

Application of acrylamide as an embedding medium in studies of lectin and antibody binding in the vertebrate retina.

The use of acrylamide as an embedding medium for vertebrate retinal tissue and its applicability to lectin and antibody-based cytochemical studies is described. The acrylamide technique has numerous advantages over those using fresh-frozen or paraffin embedded material. The morphological integrity of retinal tissue prepared in acrylamide is equivalent to that obtainable with paraffin and superior to that of fresh-frozen material. In addition, this technique alleviates problems often encountered with the thermal and chemical treatments required in the paraffin method. The acrylamide technique allows the localization of lectin and antibody-binding sites essentially unaltered by the fixation and embedding protocol, as in frozen sections, while maintaining tissue morphology similar to that of paraffin-embedded tissue. It is hoped that this approach will be useful to other workers in vision research employing lectin, antibody or other cytochemical approaches to the study of cellular structure and function.

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PubMed2005

Chromosome aberrations in tunnel workers exposed to acrylamide and N-methylolacrylamide.

OBJECTIVES: The aim of this study was to examine chromosome aberrations in 25 tunnel workers exposed to acrylamide-containing grout in injection work. METHODS: Blood samples were collected from 25 exposed and 25 unexposed tunnel workers matched for age, gender, and smoking habits. Whole blood was cultured for 50-53 hours according to conventional methods. Chromosome damage was scored in 200 metaphases per person on coded slides. The distribution of glutathione S-transferase (GST) genotypes (M1 and T1) was examined for all the workers. Exposure assessment was performed with detailed interviews and questionnaires. RESULTS: The chromosome examinations showed no statistically significant differences between the 25 exposed and 25 unexposed workers for cells with chromosome aberrations or for chromatid breaks, chromosome breaks, and chromosome gaps. The exposed workers had a significantly higher number of chromatid gaps (mean 10.6, SD 5.6) than the unexposed workers (mean 6.4, SD 4.4, P=0.004), but there was no exposure-response relationship. The limited stratum-specific numbers showed that the exposed workers with the GSTM1-/GSTT1-genotype had nonsignificantly higher frequencies of all the effect parameters than the unexposed workers; this finding indicates that individual susceptibility related to the detoxification of acrylamide and N-methylolacrylamide may have played a role in the observed effect. CONCLUSIONS: No increase in chromosome breaks or aberrations was observed for 25 workers exposed to acrylamide-containing grout during tunnel work. The increased frequency of chromatid gaps in the exposed workers may indicate a slight genotoxic effect related to exposure to acrylamide or N-methylolacrylamide.

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PubMedDate not supplied

Effects of acrylamide on multiple behavioral endpoints in the pigeon.

Little is known about acrylamide's effects on cognitive function in animals. Twelve pigeons were trained to stable levels of performance. We then determined the effects of subchronic exposure (p.o.) of 0, 20, and 60 mg/kg/day of acrylamide monomer on (1) duration discrimination responding; (2) fixed-interval performance; and (3) shape discrimination responding. Sixty mg/kg/day caused rapid impairment on all tests; recovery of various endpoints varied from 2 or 3 days to more than 4 weeks. Response latency recovered much more rapidly than the accuracy of duration discrimination. Measures of responding and discrimination recovered at approximately the same time for the FI and shape discrimination. FI response rate remained elevated post-acrylamide. Administration of 20 mg/kg/day for 90 days produced a consistent, but not significant, decrease in the accuracy of duration discrimination. Acrylamide affects a variety of behavioral processes involving sensory, motor and associative functions.

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PubMed1984

A simple, sensitive method for detecting early peripheral nerve dysfunction in the rat following acrylamide treatment.

The "ocular zingerone test" was employed to detect early alterations in peripheral nerve function which were associated with acrylamide intoxication in the rat. Acrylamide treatment resulted in a dose-related prolongation of the behavioral response to ocular zingerone. Significant alterations in the zingerone response occurred prior to detectable alterations in peripheral sensory and motor nerve function. Acrylamide-induced prolongation of the zingerone response appears to be the result of functional alterations in cholinergic neurotransmission in the autonomic nervous system. It is concluded that the "ocular zingerone test" is a simple, sensitive technique with which the degree of acrylamide intoxication may be quantified in the rat.

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PubMed1998

Liquid chromatography/tandem mass spectrometry to monitor acrylamide adducts with bovine beta-lactoglobulin B.

Complexation of acrylamide with bovine beta-lactoglobulin B and some of its tryptic fragments have been examined by liquid chromatography coupled to tandem mass spectrometry. Such complexation was investigated both in the presence and in the absence of dithiothreitol as a reducing agent. Under the latter conditions, the intact protein exhibited a single cysteine-acrylamide complex which both the present work and previous studies attribute to Cys160. The involvement of this particular residue is tentatively attributed to an intramolecular disulphide exchange which results in its disengagement from the S-S bridge to offer a free SH group for reaction with the acrylamide monomer. In the absence of dithiothreitol, both free and complexed cysteine-containing tryptic fragments were present, while in its presence, one of the tryptic fragments, which contains three cysteine residues was fully absent, instead a part of this fragment containing two cysteines complexed with two acrylamide monomers was observed. The absence of any analytical information in the literature regarding the latter complexes underlines the potential of liquid chromatography coupled to mass spectrometry in the characterization of this commonly occurring modification.

Acrylamides↗

PubMed1978

Attenuated dynamic responses of primary endings of muscle spindles: a basis for depressed tendon responses in acrylamide neuropathy.

Depressed or lost tendon reflexes commonly observed in patients with peripheral neuropathies may result partly from attenuation of the dynamic discharge from the primary endings of muscle spindles. This possibility was investigated in cats with an experimental neuropathy induced with acrylamide (30 mg/kg/day intramuscularly). Achilles tendon reflexes and the dynamic discharge from primary muscle spindles were evaluated after five or ten injections of acrylamide. After five injections the animals were moderately impaired neurologically, the Achilles tendon reflex was difficult to elicit in 2 of 5 animals, and the dynamic responses of primary endings of soleus muscle spindles to stretch were depressed. Following ten injections of acrylamide the cats were severely impaired neurologically; tendon responses were either absent or difficult to elicit, and the dynamic responses of their muscle spindles to stretch were reduced by 50% (p less than 0.01). Additionally, the spindels responded to stretch with only 20 to 30% the normal number of afferent impulses. These data suggest that lost tendon responses in acrylamide neuropathy result in part from inadequate activation of motoneurons by spindle afferent discharge.

Acrylamides↗

PubMed2006

Study of different atmospheric-pressure interfaces for LC-MS/MS determination of acrylamide in water at sub-ppb levels.

A rapid, sensitive and selective method based on LC-MS/MS has been developed for the direct determination of acrylamide residues in water in compliance with the current European Union (EU) 98/83 Drinking Water Directive. Given the high polarity of acrylamide, the application of a rapid on-line solid phase extraction step, commonly used for preconcentrating low analyte levels, was not found to be completely satisfactory. Therefore, an alternative approach based on the use of direct large-volume injection into the LC-MS/MS system has been used. Three atmospheric-pressure interfaces (ESI, APCI and Ion Sabre APCI) were checked to reach the required sensitivity (0.1 microg/l). All three interfaces were tested by analysis of six different water samples (surface water, groundwater, drinking water and three treated water samples) spiked at three concentration levels each (0.1, 1 and 10 microg/l). When using ESI, poor sensitivity and high matrix effects were observed. This situation improved when APCI was used as the interface because no matrix effect was found, although sensitivity was not completely satisfactory. The best results were obtained by interfacing the Ion Sabre APCI; its higher sensitivity for acrylamide (LOD 0.03 microg/l) and the absence of matrix effects recommended its selection. Using this approach, satisfactory recoveries (90-97%) and precision (<12%) were obtained for all water samples studied. Besides, the acquisition of two different MS/MS transitions allowed not only the quantification but also the confirmation of acrylamide in water at concentration levels around 0.1 microg/l.

Acrylamides↗

PubMed2005

The effect of cooking on acrylamide and its precursors in potato, wheat and rye.

The relationship between acrylamide and its precursors, namely free asparagine and reducing sugars, was studied in simple cakes made from potato flake, wholemeal wheat and wholemeal rye, cooked at 180 degrees C, from 5 to 60 min. Between 5 and 20 min, large losses of asparagine, water and total reducing sugars were accompanied by large increases in acrylamide, which maximized in all three products between 25 and 30 min, followed by a slow linear reduction. Acrylamide formation did not occur to any extent until the moisture contents of the cakes fell below 5%. A comparison of each type of cake with a commercial product, made from the same food material, showed that acrylamide levels in all three commercial products were well below the maximum levels in the cooked cakes.

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PubMed2005

LC/MS/MS method for the analysis of acrylamide and glycidamide hemoglobin adducts.

Hemoglobin adducts of acrylamide and its primary metabolite, glycidamide are used as biomarkers of acrylamide exposure. Several methods for analyzing these biomarkers in blood have been described previously. These methods were developed to analyze small numbers of samples, not the high sample throughput that is needed in population screening. Obtaining data on exposure of the US population to acrylamide through food and other sources is important to initiate appropriate public health activities. As part of the Centers for Disease Control and Prevention biomonitoring activities, we developed a high throughput liquid chromatography tandem mass spectrometry (LC/MS/MS) method for hemoglobin adducts of acrylamide. The LC/MS/MS method consists of using the Edman reaction and isolating the reaction products by protein precipitation and solid-phase extraction (SPE). Quantitation is achieved by using stable-isotope labeled peptides as internal standards. The method is performed on an automated liquid handling and SPE system. It provides good sensitivity in the low-exposure range as assessed in pooled samples and enables differentiation between smokers and non smokers.

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