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PubMed1988

Genotoxic effects of a sub-acute low-level inhalation exposure to a mixture of carcinogenic chemicals.

A study was conducted using a combined testing protocol (CTP), to determine whether short-term biological end-points, singly or in combination, are sufficiently sensitive to identify damage induced by exposure to ambient levels of industrial chemicals. A small-scale inhalation set-up which is both economical and easy to assemble was designed. Mice were exposed to 4 concentrations of a custom-blend mixture of benzene, chloroprene, epichlorohydrin and xylene in a ratio of 2:2:1:2, respectively. The concentrations for benzene, chloroprene and xylene were 0, 0.1, 1.0 and 10 ppm each. Concentrations for epichlorohydrin were half those for the other components. Groups of 22 males and 22 female mice were exposed to each concentration of the mixture for 3 and 6 weeks. Selected biological end-points including urine mutagenesis, bone marrow cell aberrations and micronuclei, spleen lymphocyte aberrations and liver enzyme induction were monitored. The spleen lymphocyte aberrations and liver enzyme induction were the most sensitive end-points. The lymphocytes showed a significant induction of chromosome aberrations from exposure for 3 weeks to all 3 concentrations of the mixtures. After 6 weeks of exposure, significant induction of aberrations was observed after exposure to low and medium concentrations but not to the high concentration. This lack of response at the high concentration after 6 weeks exposure, appeared to correlate with a significant induction of glutathione S-transferase in the liver. Since this enzyme is known to detoxify 3 of the 4 chemicals in our mixture, it may indicate a detoxification mechanism after enzyme induction. The present study indicates that the CTP is sufficiently sensitive to identify toxicological effects after exposure to ambient levels of a gas mixture.

Administration, Inhalation↗
PubMed2002

Preparation of agricultural residue anion exchangers and its nitrate maximum adsorption capacity.

Anion exchangers were prepared from different agricultural residues (AR) after reaction with epichlorohydrin and dimethylamine in the presence of pyridine and N,N-dimethylformamide (EDM method). Agricultural residues anion exchangers (AR-AE) produced by the EDM method were inexpensive and showed almost the same NO3- removal capacities as Amberlite IRA-900. AR-AE produced from AR with higher hemicelluloses, lignin, ash and extractive contents resulted in the lower yields. Sugarcane bagasse with the highest alpha-cellulose contents of 51.2% had the highest yield (225%) and lowest preparation cost. The highest maximum adsorption capacity (Qmax) for nitrate was obtained from rice hull (1.21 mmol g(-1)) and pine bark natural exchangers (1.06 mmol g(-1)). No correlation was found between Qmax and alpha-cellulose content in the original AR. AR-AE produced from different AR demonstrated comparable Qmax due to the removal of non-active compounds such as extractives, lignin and hemicelluloses from AR during the preparation process. Similar preparation from pure cellulose and pure alkaline lignin demonstrated that the EDM method could not produce anion exchangers from pure lignin due to its solubilization after the reaction with epichlorohydrin.

Adsorption↗
PubMed1999

Physico-chemical characterization of Ca-alginate microparticles produced with different methods.

In the present paper the physico-chemical characterization of Ca-alginate microparticles produced with different methods is presented. Ca-alginate microparticles were obtained either by emulsification method or by dripping an aqueous alginate solution into a solution of calcium salt. Inverse Size Exclusion Chromatography (ISEC) was used for the determination of dimensions of the pores and porous volume of microparticles having a mean diameter of 220 microm when obtained by emulsification method. The same technique was used to study the variation of the pore size and porous volume with pH. The results were related with the content of calcium and sodium in the microparticles, before and after their treatment with different HCl solutions. For the particles with a mean diameter of 1.2 mm (obtained by dripping method) we adopted an other approach based on the steric exclusion of solute at equilibrium. For a convenient interpretation of the obtained data, determination of water regain, swelling degree, and scanning electron microscopy (SEM) were performed. Finally, a comparison of the characteristics of microparticles produced by ionic and epichlorohydrin crosslinkings was made. The maximum dimensions of the pores of the microparticles obtained by emulsification were found smaller than those obtained by other technics. The variation of the dimensions of the pores and porous volume with pH is not significant. The structure of the chemically crosslinked beads with epichlorohydrin is more elastic and the swelling is reversible; after drying and reswelling process, the dimensions of the pores and porous volume of these microparticles remain unchanged. On the opposite, for the microparticles obtained by emulsification or dripping method in the presence of calcium ions, these characteristics are changed after a first drying process.

Alginates↗
PubMed2004

Active site engineering of the epoxide hydrolase from Agrobacterium radiobacter AD1 to enhance aerobic mineralization of cis-1,2-dichloroethylene in cells expressing an evolved toluene ortho-monooxygenase.

Chlorinated ethenes are the most prevalent ground-water pollutants, and the toxic epoxides generated during their aerobic biodegradation limit the extent of transformation. Hydrolysis of the toxic epoxide by epoxide hydrolases represents the major biological detoxification strategy; however, chlorinated epoxyethanes are not accepted by known bacterial epoxide hydrolases. Here, the epoxide hydrolase from Agrobacterium radiobacter AD1 (EchA), which enables growth on epichlorohydrin, was tuned to accept cis-1,2-dichloroepoxyethane as a substrate by accumulating beneficial mutations from three rounds of saturation mutagenesis at three selected active site residues, Phe-108, Ile-219, and Cys-248 (no beneficial mutations were found at position Ile-111). The EchA F108L/I219L/C248I variant coexpressed with a DNA-shuffled toluene ortho-monooxygenase, which initiates attack on the chlorinated ethene, enhanced the degradation of cis-dichloroethylene (cis-DCE) an infinite extent compared with wild-type EchA at low concentrations (6.8 microm) and up to 10-fold at high concentrations (540 microm). EchA variants with single mutations (F108L, I219F, or C248I) enhanced cis-DCE mineralization 2.5-fold (540 microm), and EchA variants with double mutations, I219L/C248I and F108L/C248I, increased cis-DCE mineralization 4- and 7-fold, respectively (540 microm). For complete degradation of cis-DCE to chloride ions, the apparent Vmax/Km for the Escherichia coli strain expressing recombinant the EchA F108L/I219L/C248I variant was increased over 5-fold as a result of the evolution of EchA. The EchA F108L/I219L/C248I variant also had enhanced activity for 1,2-epoxyhexane (2-fold) and the natural substrate epichlorohydrin (6-fold).

Agrobacterium tumefaciens↗
PubMed2004

Development of protamine hollow-fiber device for extracorporeal heparin removal.

Protamine was covalently coupled to a cellulose hollow fiber (cuprophan membrane) through epichlorohydrin-activated hydroxyl groups on the hollow fiber. An immobilization efficiency of as much as 15 mg protamine/g fiber could be achieved under optimal reacting conditions. Compared to a protamine hollow-fiber device produced using cyanogen bromide as an activator, the protamine hollow-fiber device using epichlorohydrin as an activator shows very high resistance to hydrolysis. Both in vitro and in vivo experiments showed that such a protamine hollow-fiber device had high heparin-removal capacity and efficiency, suggesting that this device may be suitable for various clinical applications in extracorporeal heparin removal.

Adsorption↗
PubMed1997

Purification of amylases and other enzymes by a forced-affinity chromatography method.

An affinity matrix of soluble starch gel was prepared by cross-linking catalyzed by epichlorohydrin. The elution pattern of Taka-amylase A (TAA) indicated that the amount of enzyme bound to the starch gel column increased with increases in the ammonium sulfate (AmS) concentration in the equilibrating buffer. TAA had an affinity for the gels with a starch structure, and desorbed from the column with the buffer containing no AmS. Bound TAA was also eluted with starch and cyclodextrin solution. The AmS stimulative effect was partially replaced by polyethylene glycol and surfactants. Besides TAA, various, other amylases bound satisfactorily to the starch gel. Moreover, affinity purifications of dextranase, cellulase, and pectinase were done by gels with dextran, cellulose, and pectin structures, respectively. By the aid of forced effects of AmS, various carbohydrases could be purified by the affinity gels of polysaccharide linked by epichlorohydrin.

Adsorption↗
PubMed1995

Modifications of neurofilament proteins by possible metabolites of allyl chloride in vitro.

Chronic exposure to allyl chloride (ALL) is known to produce a central-peripheral distal axonopathy. In relation to the mechanism(s), the present study was conducted to examine the abilities of ALL and its putative metabolites, i.e., epichlorohydrin, glycerol alpha-monochlorohydrin, allyl alcohol and acrolein to cross-link proteins in vitro. Neurofilament-riched cytoskeletal proteins (1mg/ml) and ovalbumin (10mg/ml) were incubated with 160 mM tested chemicals except for acrolein at 0.5 mM and 1 mM. Time-dependent studies by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed that not only ALL, but also acrolein and epichlorohydrin exerted chemical modifications on axonal cytoskeletal proteins; while only acrolein-treated ovalbumin could manifest evidence of polymerization of the protein. Immunoblotting of PAGE-separated proteins confirmed that the high molecular weight proteins on the top of SDS-PAGEs were NF antigen-contained covalent cross-linked materials.

1-Propanol↗
PubMed2001

[Preparation and quality control of cross-linked agarose coated activated charcoal (CAAC-II) used as adsorbents for hemoperfusion in artificial liver support].

The preparation and the quality control of cross-linked agarose coated activated (CAAC-II) were described. The crosslinking reagent epichlorohydrin was removed. Investigations indicate that the trace elements such as Pb, Cd, As, Cr, Fe and heavy metals, the pH, NH4+, SO4(2-), and ultraviolet absorbance in sample have met the requirements in Chinese Pharmacopeia and some other relevant standard promulgated by the Ministry of Health. No epichlorohydrin was detected in CAAC-II.

Capsules↗
PubMedDate not supplied

Well defined dye adsorbents for protein purification.

When activating a matrix with epichlorohydrin, the degree of activation can be controlled by the amount of epichlorohydrin added and the length of time of the reaction. The epoxy group can react with thiols and amines to produce N- and S-linked adsorbents for protein purification. The epoxy-activated gel may also react with ammonia to produce an amino-activated adsorbent. This adsorbent reacts readily with the reactive groups of textile dyes, coupling the dyes to the matrix via a short spacer arm. Conditions can be found where the reaction of the dyes with hydroxyl groups on the matrix is minimized, producing dye-ligand adsorbents with well defined ligand densities. These dye adsorbents can be made with much higher ligand densities than are normally achievable with the conventional coupling via hydroxyl groups on the matrix. The protein-binding behaviour of the highly substituted adsorbents is qualitatively similar to that of the conventional adsorbents but the capacity increases with increase in ligand density. Too high a ligand density is undesirable as it may become difficult to elute the proteins from the adsorbent. The optimum ligand density was found to be between 2 and 10 mumol dye ligand per mL adsorbent, the levels chosen for the low- and high-dye kits of dye adsorbents for protein purification (Rainbow-sorb).

Alcohol Dehydrogenase↗
PubMed2003

Intrinsic rotation and molecular structure.

The intrinsic rotation, limiting value of specific rotation at zero concentration, of (R)-(-)-epichlorohydrin was measured in four different solvents, CH(3)OH, CH(2)Cl(2), CHCl(3) and CCl(4). It was found that the sign of rotation in CH(3)OH, and CH(2)Cl(2) solvents is opposite to that in CCl(4). The intrinsic rotation in CHCl(3) is close to zero. This observed pattern was explained using density functional calculations of specific rotation using very large basis sets. It was found that the g-I and g-II conformations of epichlorohydrin have nearly the same magnitude of specific rotation but with opposite sign. When these two conformations have equal populations, as in CHCl(3) solvent, the net rotation is close to zero. When g-II conformation dominates, as in CCl(4) solvent, the observed sign of rotation will be opposite to that when g-I conformation dominates, as in CH(2)Cl(2) and CH(3)OH solvents. A combination of intrinsic rotation measurement with density functional prediction of specific rotation is demonstrated to be a practical method for determining the structures of molecules.

Journal Article↗
PubMed1987

Vaporization technique to measure mutagenic activity of volatiles organic chemicals in the Ames/Salmonella assay.

The purpose of this research was to develop and characterize a sensitive test method to detect mutagenic activity of volatile liquid organic chemicals (i.e, volatiles) in the Ames/Salmonella assay. A Tedlar bag vaporization technique was developed, which increased contact time between the volatiles and bacterial test system, circumvented volatilization limitations in the standard plate incorporation and preincubation methods, allowed chemical analysis during incubation, and was flexible in design. The vaporization technique was evaluated concurrently against the plate incorporation and preincubation techniques with eight liquid volatile mutagens in the Ames/Salmonella mutagenicity assay with Salmonella typhimurium strains TA100 and TA102. Results suggested that when volatile organic chemicals with boiling points below 63 degrees C were tested for mutagenic activity, the most sensitive test conditions were the vaporization technique with TA100. GC analysis of epichlorohydrin and butylene oxide concentrations within Tedlar bags suggested that these two chemicals volatilized and were contained in the media after 1 hr of incubation at 37 degrees C. The mutagenic activity of six volatile liquid mutagens was similar in single and triple plate Tedlar bags. Three general test groups of volatile organic chemicals were identified by test data: chemicals which had boiling points below 63 degrees C, for which the vaporization technique was the most sensitive test procedure (ethylene, propylene, and butylene oxides and methylene chloride); chemicals which had boiling points from 107 degrees to 132 degrees C, for which the vaporization technique was still useful, but where sensitivity was only slightly increased over the preincubation technique (1-bromo-2-chloroethane, epichlorohydrin, and ethylene dibromide); and 3) a chemical which had a boiling point at 194 degrees C, where the preincubation technique was the most appropriate test method (styrene oxide).

Animals↗
PubMed1984

Respiratory tract lesions induced by sensory irritants at the RD50 concentration.

Exposure of mice to airborne sensory irritants causes a concentration-dependent depression of respiratory rate. The RD50 concentration (that concentration which elicits a respiratory rate decrease of 50%) has been predicted to be an unacceptable occupational exposure concentration due to intolerable sensory irritation and possible respiratory tract injury in humans. The purpose of this study was (1) to determine whether lesions occur in the respiratory tract of Swiss-Webster mice after exposure to the RD50 concentrations of ten sensory irritants and (2) to compare these changes with respect to type and severity. The RD50 values (ppm) of the chemicals studied are as follows: 2,4-toluene diisocyanate (0.4), acrolein (1.7), formaldehyde (3.1), chloropicrin (8.0), chlorine (9.3), sulfur dioxide (117), ammonia (303), hydrogen chloride (309), dimethylamine (511), and epichlorohydrin (687). After exposure of mice for 6 hr/day for 5 days, the respiratory tract was examined for histopathologic changes. All irritants produced lesions in the nasal cavity with a distinct anterior-posterior severity gradient. There was considerable variation in the extent, and nature of the lesions. The lesions ranged from slight epithelial hypertrophy or hyperplasia to epithelial erosion, ulceration, and necrosis with variable inflammation of the subepithelial tissues. Only chlorine, chloropicrin, and epichlorohydrin induced lesions in the lower respiratory tract. These findings give additional support to the potential value of the RD50 model for setting occupational exposure guidelines and predicting the risk of injury to the respiratory tract from exposure to airborne sensory irritants.

Animals↗
PubMed1986

Comparison of two routes of chemical administration on the lung adenoma response in strain A/J mice.

This study was undertaken to determine the ability of a series of 19 compounds representing different chemical classes of carcinogens to induce lung tumors in strain A/J mice after either ip or po administration. Aflatoxin B1, dibutylnitrosamine, 1,2-dimethylhydrazine, and methylnitrosourea induced a significant increase in the lung tumor response in both sexes after ip and po administration. Azaserine was active in both sexes only after ip administration. Benzene, 1,2-dibromoethane, and epichlorohydrin, following ip administration, produced significant increases in the tumor response in at least one sex. Aflatoxin B1, azaserine, benzene, 1,2-dibromoethane, dibutylnitrosamine, and epichlorohydrin were more active when given ip than after po administration. In contrast, dimethylhydrazine and methylnitrosourea were more active (in females only) when given po. 2-Acetylaminofluorene, azobenzene, chloroform, 1,4-dioxane, FANFT (N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide), lead subacetate, methylmethanesulfonate, beta-naphthylamine, beta-propiolactone, safrole, and 2,4,6-tri-chlorophenol did not induce lung tumors in strain A/J mice. These data confirm previous observations on the importance of the route of chemical administration on the lung tumor response in strain A mice, and on the inability of the lung tumor bioassay to detect certain liver and bladder carcinogens and unstable alkylating agents.

Adenoma↗
PubMed1995

Separation of immunoglobulin G from human serum by pseudobioaffinity chromatography using immobilized L-histidine in hollow fibre membranes.

L-Histidine, intended as a pseudobiospecific ligand, was immobilized on poly(ethylenevinyl alcohol) hollow fibre membranes after their activation with epichlorohydrin or butanediol diglycidyl ether. The affinity membranes obtained allowed the one-step separation of immunoglobulin G (IgG) from untreated human serum. Elution was possible under mild conditions with discontinuous pH or salt gradients. IgM was also adsorbed to a certain extent and partially separated from IgG by pH gradient elution. The bound IgG fractions showed pI values between 8 and 9.5 and contained IgG1 and IgG3. The dissociation constants for IgG on the bisoxirane- and epichlorohydrin-activated membranes coupled with histidine were determined by equilibrium binding analysis to be 2.5 x 10(-5) and 2.0 x 10(-5) M, respectively. The maximum binding capacity of the affinity hollow fibre membranes was 80 and 70 mg of IgG per gram of support, respectively. With a cartridge of surface area 1 m2 (about 19 g of fibres), during a 60-min run, theoretically up to 1.5 g of IgG can be removed from human serum. The histidine affinity membranes are very stable owing to the simple nature of the ligand and the coupling via an ether linkage. Reproducible results were obtained over more than 1 year even with untreated human serum being used regularly.

Adsorption↗
PubMed2000

Acyclic distonic acylium ions: dual free radical and acylium ion reactivity in a single molecule

Three gaseous acyclic distonic acylium ions: *CH2-CH2-C+=O, *CH2-CH2-CH2-C+=O, and *CH2=C(CH2)-C+=O, are found to display dual free radical and acylium ion reactivity; with appropriate neutrals, they react selectively either as free radicals with inert charge sites, or (and more pronouncedly) as acylium ions with inert radical sites. The free radical reactivity of the ions is demonstrated via the Kenttamaa reaction: CH3S* abstraction with the spin trap dimethyl disulfide; their ion reactivity by two reactions most characteristic of acylium ions: transacetalization with 2-methyl-1,3-dioxolane and the gas-phase Meerwein reaction, that is, expansion of the three-membered epoxide ring of epichlorohydrin to the five-membered 1,3-dioxolanylium ion ring. In "one-pot" reactions with gaseous mixtures of epichlorohydrin and dimethyl disulfide, the ions react selectively at either site, but more readily at the acylium charge site, to form the two mono-derivatized ions. Further reaction at either the remaining free radical or acylium charge site forms a single bi-derivatized ion as the final product. Becke3LYP/6-31G(d) calculations predict the reactions at the acylium charge sites of the three distonic ions to be highly exothermic, and both the "hot" transacetalization and epoxide ring expansion products of *CH2-CH2-CH2-C+=O to dissociate rapidly by H2C=CH2 loss in overall exothermic processes. The calculations also predict highly spatially separate odd spin and charge sites for the novel cyclic distonic ketal ions formed by the reactions at the acylium charge sites.

Journal Article↗
PubMed2006

Transient signal analysis using complementary metal oxide semiconductor capacitive chemical microsensors.

This work explores the possibility to discriminate analytes based on their nonequilibrium signals in polymer-coated capacitive chemical microsensors. The analyte uptake in the chemically sensitive polymer layers of 3-7-microm thickness has been analyzed using a diffusion model and the dynamic sensor response data. The shapes of the response profiles have been calculated analytically. Despite the simplifications in the model, the observed transient signal profiles could be described accurately. Comparison of the measured diffusion coefficients (on the order of 10(-12) m2/s) with literature values measured at similar concentration levels showed good agreement. Concentration-independent diffusion coefficients for several analyte/polymer combinations (poly(etherurethane)/all analytes; poly(epichlorohydrin)/alcohols) as well as slightly concentration-dependent diffusion coefficients (poly(epichlorohydrin)/toluene or ethyl cellulose/toluene) have been found in the investigated concentration range of tens to hundreds of pascals gas-phase partial pressure. The diffusion times of water and the first aliphatic monohydric alcohols in the polymers are strongly correlated to their molecular size. The discrimination of these substances based on dynamic sensor data of a single sensor could be demonstrated. In particular, the analysis of mixtures of analytes with similar chemical behavior (water/ethanol or methanol/ethanol) by means of analyzing the response profile of single-exposure steps or by applying a series of decreasingly long alternating target gas exposure and carrier gas exposure steps has been performed.

Journal Article↗
PubMed1981

Ring-hydroxylated propranolol: synthesis and beta-receptor antagonist and vasodilating activities of the seven isomers.

Propranolol (Inderal; 1) is extensively metabolized in man. Metabolites of interest pharmacologically include ring-hydroxylated propranolols (1a-g). In order to identify these ring-oxidized products and to study the effect of hydroxyl position on biological activity, we have synthesized all seven isomers. With the exception of 1b and 1g, the desired compounds were prepared by alkylation of the respective methoxy-1-naphthols with epichlorohydrin and reaction of the resulting epoxide with isopropylamine. Cleavage og the methyl group in fused pyridine hydrochloride afforded 1a,c-f. 1g was prepared by the direct alkylation of 1,8-naphthalenediol (17) with epichlorohydrin, followed by reaction with isopropylamine. 1b was synthesized by treating 2-naphthol (9) with chlorine gas and then treating the resulting 1,1-dichloronaphthalen-2(1H)-one (10) with sodium allyl oxide. Acetylation of the hydroxy function and epoxidatrion of the allyl group, followed by relation with isopropylamine, gave 3'-hydroxy-4'-chloropropranolol (15). Dechlorination gave 1b. All of the racemic hydroxylated propranolols produced beta blockade and direct vasodilation in anesthetized dogs. The potency is strongly dependent upon the position of the hydroxyl group, i.e., 1e is 4 times as potent as 1 as a beta receptor antagonist, whereas 1a, 1b, and 1g are all significantly less potent than 1. For direct vasodilation, 1a and 1g are equipotent to 1, while 1b-f are much less potent. The potencies of the compounds were also compared with their 1-octanol/pH 7.4 buffer distribution coefficients; the direct vasodilating potency was found to increase with increasing lipophilicity, while the beta-adrenergic antagonist potency decreased.

Adrenergic beta-Antagonists↗
PubMed1998

Substituted 4-acylpyrazoles and 4-acylpyrazolones: synthesis and multidrug resistance-modulating activity.

A series of 4-acyl-3-pyrazolone derivatives with a 3-substituted 2-hydroxy-3-aminopropyl chain attached to pyrazole N-1 (7-20) as well as isomeric 4-acyl-5-(3-substituted 3-amino-2-hydroxypropoxy)pyrazole derivatives (5, 6) were synthesized, and their multidrug resistance (MDR)-modulating activity was measured using the daunomycin efflux assay. Reaction of N1-substituted 4-acyl-3-pyrazolones (tautomer to 4-acyl-5-hydroxypyrazoles) with excessive epichlorohydrin and successive treatment with an appropriate amine resulted in N-alkylation and thus afforded the target pyrazolone derivatives 7-20. In contrast, O-alkylation occurred upon reaction with 1 equiv of epichlorohydrin and subsequent treatment with amine leading to the corresponding 4-acyl-5-pyrazolyl ethers 5 and 6. QSAR studies showed a good correlation of MDR-modulating activity with lipophilicity of the compounds. Inclusion of hydrogen bond acceptor strength and steric parameters as descriptors led to a QSAR equation with remarkably increased predictive power (r2cv = 0.92). Additionally, ortho substitution of the propanolamine side chain and the acyl moiety is favorable. Detailed NMR spectroscopic investigations were carried out with the title compounds.

ATP Binding Cassette Transporter, Subfamily B, Mem↗