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PubMedDate not supplied

The effects of thioctic acid on motor nerve terminals in acrylamide-poisoned rats.

Acrylamide causes a distal neuropathy by combining with and depleting glutathione and other sulphydryl-containing compounds in axons and nerve terminals. This results in damage to the axon membrane and impaired efficiency of synaptic vesicle recycling. The changes may be assessed by staining nerve terminals in muscle with zinc iodide and osmium, a technique which depends upon the presence of sulphydryl compounds for the development of the stain. The present experiments were designed to test whether thioctic acid, itself a sulphydryl-containing compound, could protect against acrylamide-induced damage of motor nerve terminals. In vitro and in vivo experiments on acrylamide-poisoned rats showed that thioctic acid was able to maintain the integrity of the nerve terminal membrane, as shown by the ability of the terminals to develop 'spontaneous' sprouts and to stain with the zinc iodide osmium technique. Thioctic acid treatment also enhanced recovery after partial denervation of muscles in both normal and acrylamide-poisoned animals. The results suggest that thioctic acid is itself able to react with the acrylamide before the latter has a chance to bind and deplete axonal and nerve terminal glutathione.

Acrylamide↗

PubMed1985

Alteration of intermediate filament distribution in PtK1 cells by acrylamide.

PtK1 cells were treated with low concentrations of acrylamide resulting in disruption of intermediate filament networks. An optimum treatment, 5 mM acrylamide in culture medium for 4 h, resulted in formation of a juxtanuclear aggregate containing both keratin and vimentin intermediate filaments. Actin-containing stress fibers and microtubules appeared normal after this treatment. Cells recovered when acrylamide was washed out of the cultures, and normal keratin and vimentin networks reappeared. These cells were capable of proliferation and grew to confluence. Acrylamide-treated cells appeared to locomote normally, showing membrane ruffling and changes in shape, but cytoplasmic organelles did not appear to move normally throughout the cell but remained at the cell center. These observations indicate that acrylamide is a useful intermediate filament inhibitor that does not affect other cytoskeletal elements.

Acrylamide↗

PubMed1985

Biochemical studies of acrylamide neuropathy.

Studies on the toxicokinetics and biochemical effects of acrylamide are reviewed in regard to their implications concerning the mechanism of acrylamide induced neuropathy. Specifically, investigations of the effects of acrylamide on several glycolytic enzymes including neuron-specific enolase and glyceraldehyde-3-phosphate dehydrogenase are evaluated. Both of these enzymes are decreased in activity in animals exhibiting clinical signs of neuropathy induced by acrylamide. The significance of these findings in terms of the mechanism of action of acrylamide is discussed.

Acrylamide↗

PubMed1985

NMR analyses of the cold cataract. III. 13C acrylamide studies.

13C-enriched acrylamide was employed to further delineate the action of this compound in preventing the cold cataract phenomenon when it is incorporated (in vitro) into young human and rabbit lenses. The extent of acrylamide incorporation, in the dark and with concurrent UV exposure, was monitored by 13C NMR spectroscopy. These studies provide further evidence that UV exposure causes permanent acrylamide photobinding within the lens. In such lenses, the gamma crystallin fraction of the soluble lens proteins is affected to the greatest extent. It appears to become aggregated and/or combined with the alpha and beta fractions resulting in an apparent loss of most of the gamma monomers. There is also an age-related effect with respect to the amount of acrylamide that can be incorporated into the lens. The decrease in acrylamide incorporation with age directly parallels the age-related decline in gamma crystallin levels.

Acrylamide↗

PubMed1981

Rapid effects of acrylamide on spiroperidol and serotonin binding in neural tissue.

The effects of in vivo exposure to acrylamide on 3H-spiroperidol binding to striatal and (3)5-HT binding to forebrain membranes were investigated. Rats were gavaged with 100 mg/kg acrylamide and sacrificed at various times thereafter. Rapid changes were seen with specific binding of spiroperidol increasing by 1/2 hour and 5-HT binding by 2 hours after acrylamide treatment. Although the overall effect of acrylamide was to elevate binding for at least 24 hours, binding of spiroperidol may have exhibited a biphasic profile. The possibility of dual time-dependent mechanisms involved in the effects of acrylamide is discussed.

Acrylamide↗

PubMed1997

Acrylamide and 2,5-hexanedione induce collapse of neurofilaments in SH-SY5Y human neuroblastoma cells to form perikaryal inclusion bodies.

Neurofilament accumulations are characteristic of a number of neurological conditions including amyotrophic lateral sclerosis, giant axonal neuropathies and several chemically-induced neuropathies. Although the mechanism(s) leading to neurofilament accumulation are unknown, it is possible that similar processes occur both in disease and in chemically-induced neuropathies. Understanding the mechanism(s) of chemically-induced neurofilament accumulation, which is more amenable to experimental manipulation, may give insight into the neurological diseases they mimic. We have compared the effects of two chemically-dissimilar neurotoxins, 2,5-hexanedione and acrylamide, on neurofilaments in the human neuroblastoma cell line, SH-SY5Y. Both undifferentiated and differentiated SH-SY5Y cells were exposed to 2,5-hexanedione or acrylamide and changes in cytoskeletal organization examined by immunofluorescence and electron microscopy. Although distinct morphological differences have previously been characterized in the neuropathies induced by 2,5-hexanedione and acrylamide in vivo, we have found that both compounds had similar direct effects on neurofilaments in SH-SY5Y cells, inducing formation of perikaryal inclusion bodies. In addition, differentiated SH-SY5Y cells were more sensitive to both 2,5-hexanedione and acrylamide compared with undifferentiated cells. These similar effects of 2,5-hexanedione and acrylamide lend further support that a common mechanism(s) may lead to neurofilament accumulation in these neuropathies. SH-SY5Y cells provide a useful model to investigate further the biochemical basis of neurofilament accumulation.

Acrylamide↗

PubMed1998

On-line liquid chromatography/electrospray tandem mass spectrometry to investigate acrylamide adducts with cysteine residues: implications for polyacrylamide gel electrophoresis separations of proteins.

Adduction between acrylamide and cysteine residues is a post-translational modification associated with proteins separated by gel electrophoresis. In the present article, three model peptides containing 2-4 cysteine residues were reduced with dithiothreitol, incubated with acrylamide monomers and examined by on-line liquid chromatography coupled to electrospray tandem mass spectrometry. Each of the solutions examined in this work revealed the presence of four distinct components: the free peptide, two different peptide-acrylamide 1:1 adducts involving two cysteine residues at different positions within the same sequence, and the peptide-acrylamide 1:2 adducts. The use of liquid chromatography allowed the separation of components which differed only by the site of complexation of acrylamide, while the application of tandem mass spectrometry furnished reliable sequencing information permitting the identification of most cysteine residues involved in such complexation.

Acrylamides↗

PubMed1999

Probing the reactivity of S-S bridges to acrylamide in some proteins under high pH conditions by matrix-assisted laser desorption/ ionisation.

There is compelling evidence to suggest that cysteine-acrylamide adduct formation is a modification experienced by proteins separated by two-dimensional (2-D) gel electrophoresis. Whether the -SH group involved in such complexation is offered by a free or initially disulphide-linked cysteine residue remains an open question. To address this question a number of proteins containing free and/or disulphide-linked cysteine (Cys) residues have been incubated with acrylamide monomer and examined by delayed extraction matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF). These data provide strong evidence to suggest that the presence of free Cys in the investigated proteins is not the most important requirement for the observation of Cys-acrylamide adducts. Unambiguous confirmation of this deduction was obtained by analysing the tryptic digests of the same proteins by reflectron MALDI-TOF. The assignment of the adduction sites was facilitated by the mass accuracy attained for the monitored tryptic fragments and their agreement with the corresponding predicted masses reported in the Swiss-Prot database. The same data suggest that at high pH the cysteine pairing is flexible enough to allow initially S-S linked residues to complex with acrylamide. It is also plausible that the -NH(2) terminal blockage so often encountered in proteins electroblotted from 2-D maps could originate from carbamylation, and might not have anything to do with alkylation by free, unreacted acrylamide in polyacrylamide gels.

Acrylamide↗

PubMed2000

Probing acrylamide alkylation sites in cysteine-free proteins by matrix-assisted laser desorption/ionisation time-of-flight.

It is recognised that gel-separated proteins can experience a frequent modification provoked by the interaction of unpolymerized acrylamide monomers with the thiol group of cysteine to form a beta-cysteinyl-S-propionamide adduct. Other groups which have been implicated in this reaction include the hydroxyl group of tyrosine, the straightepsilon-amino group of lysine, and the free N-terminus. In a series of recent publications it has been demonstrated that at pH approximately 9.5 and in the presence of cysteine, none of these groups experienced measurable interaction with acrylamide monomers. To emphasise this conclusion we have used matrix-assisted laser desorption/ionisation with a reflectron time-of-flight mass spectrometer to examine a number of cysteine-free proteins incubated for various intervals with 30 mM acrylamide monomers at pH 9.5. These high resolution data suggest that, for short incubation times (>/=1 hour) and in the absence of cysteine, the straightepsilon-NH(2) group of lysine is the likely adduction site of acrylamide. Longer incubation times (>/=24 hours) with acrylamide monomers rendered the role of Cys as the favourite alkylation site less evident.

Acrylamide↗

PubMed2005

A method for the determination of acrylamide in bakery products using ion trap LC-ESI-MS/MS.

Acrylamide levels of bakery products, e. g., bread and bread rolls, are usually below 100 microg/kg , often even below 50 microg/kg. Therefore, usual analytical methods which have an LOQ greater, not dbl equals 25 microg/kg are not sensitive enough for detailed investigations on acrylamide formation within these commodities. An improved method for trace level determination of acrylamide in bakery products was developed using ion trap LC-ESI-MS/MS. Samples were divided into crumbs and crusts to achieve an initial concentration by removing the crumbs since these are devoid of acrylamide. After sample extraction and clean-up using multimode SPE cartridges, further analyte enrichment was accomplished by solid-phase-supported liquid-liquid extraction with ethyl acetate prior to LC-MS/MS analysis. The method was evaluated using bread, bread rolls, alkali-baked bread rolls, and toast. LOQ was calculated from the confidence interval of the calibration curve and found to be 1.7 ng/mL, corresponding to 17 microg/kg of product. When crumbs and crusts were separated, an LOQ of 10.2 microg/kg of bakery product could be obtained. As demonstrated in preliminary comparative analyses, accuracy of the method met the requirements for determination of trace level acrylamide formation in bakery products. Mean recovery was 102.4% (CV 4.5%), intermediate reproducibility revealed a CV of 2.1%, and a repeatability of CV 6.0%.

Acrylamide↗

PubMed2006

Computer vision based analysis of potato chips--a tool for rapid detection of acrylamide level.

In this study, analysis of digital color images of fried potato chips were combined with parallel LC-MS based analysis of acrylamide in order to develop a rapid tool for the estimation of acrylamide during processing. Pixels of the fried potato image were classified into three sets based on their Euclidian distances to the representative mean values of typical bright yellow, yellowish brown, and dark brown regions using a semiautomatic segmentation algorithm. The featuring parameter extracted from the segmented image was NA2 value which was defined as the number of pixels in Set-2 divided by the total number of pixels of the entire fried potato image. Using training images of potato chips, it was shown that there was a strong linear correlation (r = 0.989) between acrylamide level and NA2 value. Images of a number of test samples were analyzed to predict their acrylamide level by means of this correlation data. The results confirmed that computer vision system described here provided explicit and meaningful description from the viewpoint of inspection and evaluation purpose for potato chips. Assuming a provisional threshold limit of 1000 ng/g for acrylamide, test samples could be successfully inspected with only one failure out of 60 potato chips.

Acrylamide↗

PubMed2006

Screening of acrylamide contents in potato crisps using process variable settings and near-infrared spectroscopy.

In order to study the formation of acrylamide in potato crisps during processing, an experimental design was set up. The design variables were drying time (6 levels), frying temperature (2 levels) and frying time (8 levels). The design contained 36 samples, which were analysed for acrylamide contents using LC high-resolution mass spectroscopy (LC-HRMS), and fat contents using the Soxhlet apparatus. Prior to analysis, all potato crisp samples were ground and analysed on an NIRSystems 6500 near-infrared (NIR) spectrometer. The acrylamide contents were modelled by: (i) design variables using multiple linear regression, (ii) NIR spectra using partial least squares regression (PLSR) and (iii) design variables and NIR spectra in combination using a novel technique combining least squares regression on the former, and PLSR on the latter. The results showed that the NIR spectra alone or in combination with the design variables gave better prediction models for acrylamide than the design variables alone. This implies that the spectra contain chemical information that is not purely a result of the processing variables that were investigated in this experiment. NIR spectroscopy is proposed as a possible tool for screening and identification of potato crisps with a high acrylamide content.

Acrylamide↗

PubMed2006

Automated method for measuring globin adducts of acrylamide and glycidamide at optimized Edman reaction conditions.

The general population is exposed to acrylamide, a potential human carcinogen, through food and cigarette smoke. The assessment of human exposure to acrylamide is important in the evaluation of health risks associated with this chemical. Hemoglobin adducts of acrylamide (AA-Hb) and its primary metabolite glycidamide (GA-Hb) are established biomarkers of acrylamide exposure and methods to measure these biomarkers using modified Edman reaction are described. Only limited information about the optimal Edman reaction conditions such as pH or temperature is available for these adducts and the existing methods do not allow automation needed in biomonitoring studies. In this study, the yield of Edman products of AA-Hb and GA-Hb between pH 3-10 and at 35-55 degrees C at different time intervals, and the applicability of liquid-liquid extraction on diatomaceous earth for analyte extraction, were assessed and results were used in a new optimized method. The applicability of our optimized method was assessed by comparing results obtained with a convenience sample from 96 individuals with a conventional method. Maximum yield of Edman products was obtained between pH 6-7, heating the reaction solution at 55 degrees C for 2 h resulted in the same yields as with conventional conditions, and use of diatomaceous earth was found suitable for automated analyte extraction. Using these conditions, no difference was observed between our optimized and a conventional method. The median globin adduct values in the convenience sample are 129 pmol/g globin (range: 27-453 pmol/g globin) and 97 pmol/g globin (range: 27-240 pmol/g globin) for AA-Hb and GA-Hb, respectively. The GA-Hb/AA-Hb ratio decreases significantly with increasing AA-Hb values indicating that measurement of AA-Hb as well as GA-Hb are needed to appropriately assess human exposure to acrylamide.

Acrylamides↗

PubMed2005

Formation of acrylamide from lipids.

Heating amino acids with dietary oils or animal fats at elevated temperatures produced various amounts of acrylamide. The amount of acrylamide formation corresponded to the degree of unsaturation of the oils and animal fats. The decreasing order of acrylamide formation from dietary oils or animal fats with asparagine was sardine oil (642 microg/g asparagine) > cod liver oil (435.4 microg/g) > soybean oil (135.8 microg/g) > corn oil (80.7 microg/g) > olive oil (73.6 microg/g) > canola oil (70.7 microg/g) > corn oil (62.1 microg/g) > beef fat (59.3 microg/g) > lard (36.0 microg/g). Three-carbon unit compounds such as acrylic acid and acrolein, which are formed from lipids by oxidation also produced acrylamide by heat treatment with amino acids, in particular with asparagine. The results of the present study suggest that acrylamide forms in asparagine-rich foods during deep fat frying in the absence reducing sugars.

Acrolein↗

PubMed2005

Genetic, physiological, and environmental factors affecting acrylamide concentration in fried potato products.

The discovery of acrylamide in processed potato products has brought increased interest in the controlling Maillard reaction precursors (reducing sugars and amino acids) in potato tubers. Because of their effects on nonenzymatic browning of fried potato products, reducing sugars and amino acids have been the focus of many potato research and breeding programs. This study focused on changes in sugars and amino acids in diploid potatoes selected for their storage qualities and their effect on acrylamide formation in the fried product. In addition, a second study was performed using cultivated lines that evaluated the effect of nitrogen fertilization on amino acid levels in tubers. Glucose, fructose, sucrose, and asparagine concentrations in tubers increased upon storage at 2 degrees C. Glucose and fructose concentrations in the tubers were significantly and positively correlated with subsequent acrylamide formation in the products. Tuber sucrose and asparagine concentrations did not have an effect on acrylamide levels. Acrylamide levels in the products were significantly reduced if tubers were preconditioned before being placed in storage at 2 degrees C. Higher rates of nitrogen fertilization resulted in increased amino acid concentrations in the tubers.

Acrylamide↗

PubMed2005

The role of epidemiology in understanding the relationship between dietary acrylamide and cancer risk in humans.

Since April 2002, when the Swedish National Food Administration first reported its finding of elevated levels of the substance acrylamide in commonly consumed foods (Swedish National Food Administration, 2002), there has been considerable debate about the health effects of dietary exposure to acrylamide. In particular, researchers have speculated on whether the amount of acrylamide consumed through the typical diet could increase the risk of cancer in humans. In this paper, we review the epidemiological data to date examining dietary acrylamide in relation to cancer risk. We highlight the strengths and limitations of using epidemiology to address this public health question. Finally, we provide an overview of future directions of epidemiological research on the health effects of dietary acrylamide.

Acrylamides↗

PubMed1988

Neurofilament degradation in the nervous system of rats intoxicated with acrylamide, related compounds or 2,5-hexanedione.

Degradation of neurofilament (NF) proteins by Ca2+-activated neutral protease (CANP) was studied in the nervous system of rats treated with neurotoxic or non-neurotoxic compounds. In the tibial nerve, the degradation of NF 68K was depressed by five neurotoxic compounds: acrylamide, N-hydroxymetylacrylamide, N-isopropylacrylamide, methacrylamide and 2,5-hexanedione. A non-neurotoxic compound, diacetone acrylamide, did not show any effect on the degradation. An immunoblot analysis confirmed the reduction in the degradation and revealed a difference in the degradation pattern between the control and acrylamide-treated rats. In the spinal cord, the degradation of the three subunits of NF was depressed in animals treated with acrylamide. Although the exact mechanism of the reduction in the degradation of NF is not yet known, the present results suggest that an inhibitory effect on CANP activity might be relevant to the mechanism of neurotoxic action of acrylamide derivatives.

Acrylamides↗

PubMed1985

Effect of acrylamide and related compounds on glycolytic enzymes in rat sciatic nerve in vivo.

The effect of acrylamide and six analogues on glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and enolase in sciatic nerve was examined in rats after their prolonged administration in drinking water. After 15 days' treatment with acrylamide and N-isopropylacrylamide, slight signs of peripheral neuropathy were produced with no changes in the activity of either enzyme. N,N-dimethylacrylamide, a non-neurotoxic analogue, produced only body weight loss at this stage. After 30 days' treatment, acrylamide and N-isopropylacrylamide produced moderate signs of neuropathy, but no changes in enzyme activity. N,N-dimethylacrylamide produced a reduction in GAPDH activity as well as body weight loss. After 45 days' treatment, acrylamide, N-isopropylacrylamide, N-hydroxymethylacrylamide and N-methylacrylamide produced severe signs of neuropathy as well as body weight loss. All these analogues also produced a reduction in the two enzyme activities, except for enolase after N-isopropylacrylamide. N,N-dimethylacrylamide produced inhibition of GAPDH as well as body weight loss without neuropathy. N-tert-butylacrylamide and N,N'-methylene-bis-acrylamide induced neither neuropathy nor inhibition of either enzyme.

Acrylamides↗