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PubMed1988

Comparison of Various Staining Procedures in the Identification of Hepatozoon canis Gamonts.

The staining characteristics of gamonts of Hepatozoon canis in peripheral blood smears were evaluated. Three stains, Diff-Quik stain, Giemsa stain and a modification of the naphthol-ASD-chloroacetate esterase stain, were compared. The staining characteristics of the infected cell and the parasite were different in each stain used. The modified naphthol-ASD-chloroacetate esterase stain showed the most difference between the infected and noninfected cells, as well as a difference in staining characteristics of the parasite nucleus from those of the host nucleus. Although the parasite was identified with all stains, a definitive diagnosis was more easily obtained with the naphthol-ASD-chloroacetate esterase stain.

Journal Article↗
PubMed1992

Degradation of 1,2-dichloroethane by Ancylobacter aquaticus and other facultative methylotrophs.

Cultures of the newly isolated bacterial strains AD20, AD25, and AD27, identified as strains of Ancylobacter aquaticus, were capable of growth on 1,2-dichloroethane (DCE) as the sole carbon and energy source. These strains, as well as two other new DCE utilizers, were facultative methylotrophs and were also able to grow on 2-chloroethanol, chloroacetate, and 2-chloropropionate. In all strains tested, DCE was degraded by initial hydrolytic dehalogenation to 2-chloroethanol, followed by oxidation by a phenazine methosulfate-dependent alcohol dehydrogenase and an NAD-dependent aldehyde dehydrogenase. The resulting chloroacetic acid was converted to glycolate by chloroacetate dehalogenase. The alcohol dehydrogenase was induced during growth on methanol or DCE in strain AD20, but no activity was found during growth on glucose. However, in strain AD25 the enzyme was synthesized to a higher level during growth on glucose than on methanol, and it reached levels of around 2 U/mg of protein in late-exponential-phase cultures growing on glucose. The haloalkane dehalogenase was constitutively produced in all strains tested, but strain AD25 synthesized the enzyme at a level of 30 to 40% of the total cellular protein, which is much higher than that found in other DCE degraders. The nucleotide sequences of the haloalkane dehalogenase (dhlA) genes of strains AD20 and AD25 were the same as the sequence of dhlA from Xanthobacter autotrophicus GJ10 and GJ11. Hybridization experiments showed that the dhlA genes of six different DCE utilizers were all located on an 8.3-kb EcoRI restriction fragment, indicating that the organisms may have obtained the dhlA gene by horizontal gene transmission.

Base Sequence↗
PubMed2001

Human kidney tubules detoxify chloroacetaldehyde, a presumed nephrotoxic metabolite of ifosfamide.

The nephrotoxic effects of the antineoplastic drug ifosfamide have been attributed to its hepatic metabolite chloroacetaldehyde. The effects of chloroacetaldehyde on isolated human kidney cortex tubules metabolizing lactate (a physiologic substrate in human kidneys) were investigated. At concentrations of > or =0.5 mM, chloroacetaldehyde was toxic to the human kidney tubules, as demonstrated by a dramatic decrease in cellular ATP levels and a large increase in lactate dehydrogenase release; chloroacetaldehyde also stimulated pyruvate accumulation and inhibited lactate removal and glucose synthesis. These effects, which were associated with incomplete disappearance of chloroacetaldehyde and extensive depletion of the cellular CoA, acetyl-CoA, and glutathione contents, were prevented by the addition of thiol-protecting drugs (mesna and amifostine). Human kidney tubules were demonstrated to metabolize chloroacetaldehyde at high rates, presumably via aldehyde dehydrogenase, which is very active in human kidneys. Carbon-13 nuclear magnetic resonance spectroscopy measurements indicated that human kidney tubules converted [2-(13)C]chloroacetaldehyde to [2-(13)C]chloroacetate, the further metabolism of which was very limited. At equimolar concentrations, chloroacetate was much less toxic than chloroacetaldehyde, indicating that chloroacetate synthesis from chloroacetaldehyde by human kidney tubules represents a detoxification mechanism that could play a role in vivo in preventing or limiting the nephrotoxic effects observed during ifosfamide therapy.

Acetaldehyde↗
PubMed1997

A 13C NMR study of 2-(13)C-chloroacetaldehyde, a metabolite of ifosfamide and cyclophosphamide, in the isolated perfused rabbit heart model. Initial observations on its cardiotoxicity and cardiac metabolism.

The metabolism of 2-(13)C-chloroacetaldehyde at doses of 1.5, 2, 3 and 4 mg/kg b.w. and that of 2-(13)C-chloroacetaldehyde at a dose of 5.9 mg/kg b.w. were studied in the isolated perfused rabbit heart model using carbon-13 nuclear magnetic resonance. We have shown that, whereas chloroacetaldehyde is cardiotoxic at doses above 2 mg/kg b.w., this toxic effect is not accompanied by an increase in intramyocardial citrate levels. Chloroacetate, its main metabolite, is not cardiotoxic. The metabolism of chloroacetaldehyde is complex and leads, in addition to chloroethanol, glycolic acid, conjugates of glutathione with chloroacetate or chloroethanol (and/or their metabolites, S-(2-carboxymethyl) cysteine, N-acetyl-S-(2-carboxymethyl) cysteine, S-(2-hydroxymethyl)cysteine) and thiodiglycolic acid. Low amounts of chloroacetate are metabolized by isolated perfused rabbit hearts into glycolic acid and glutathione conjugate (and/or its metabolites, S-(2-carboxymethyl) cysteine, N-acetyl-S-(2-carboxymethyl)cysteine). The present results suggest the need to evaluate further the role that chloroacetaldehyde may play in the cardiotoxic effects of ifosfamide and cyclophosphamide.

Acetaldehyde↗
PubMed2005

Synthesis and reactions of some new substituted pyridine and pyrimidine derivatives as analgesic, anticonvulsant and antiparkinsonian agents.

A series of substituted pyridine and pyrimidine derivatives were synthesized as analgesic, anti convulsant, and antiparkinsonian agents by using compounds 1, 2, and 9 as starting materials. Pyr idino-imide derivative 3 was prepared by condensation of 1 with tetrachlorophthalic anhydride and compounds 4 and 5 were also obtained by reaction of compound 1 with 1,2,4,5-benzene-tetra carboxylic dianhydride and 1,4,5,8-naphthalenetetracarboxylic dianhydride, respectively. Similarly, compound 2 was reacted with previous anhydrides to afford the corresponding imide 6 and bis-imide derivatives 7 and 8, respectively. Bis-arylmethylene derivatives 9 were treated with hydrogen peroxide to afford the corresponding bis-oxiranocycloalkanone derivatives 10, which condensed with thiourea to give the corresponding thioxopyrimidine derivatives 11. Treatment of compound 11 with chloroacetic acid in the presence of anhydrous sodium acetate afforded the corresponding thiazolopyrim idine derivative 12 which condensed with aromatic aldehydes in acetic acid/acetic anhydride to give arylmethylene derivative 13. Also, compounds 13 could be prepared by reaction of compounds 11 with chloroacetic acid, aromatic aldehydes, and sodium acetate in a mixture of acetic acid and acetic anhydride. The pharmacological screening showed that many of these obtained compounds have good analgesic, anticonvulsant, and antiparkinsonian activities comparable to Valdecoxib, Carbamazepine, and Benzatropine as reference drugs.

Analgesics, Non-Narcotic↗
PubMed1993

Have animal data been used inappropriately to estimate risks to humans from environmental trichloroethylene?

Trichloroethylene (TCE) is widely viewed as an environmental hazard. Its major metabolite, chloral hydrate, is a currently used medicine. Regulation of TCE is based on a linear extrapolation from effects of high doses in rodents to risks for humans at low doses. However, metabolic, toxicologic, and epidemiologic data on trichloroethylene and chloral hydrate as well as water chlorination studies call this approach into question. The mechanism of carcinogenesis of TCE and chloral hydrate in rodents is nonlinear: very high doses, sufficient to cause cellular necrosis, are necessary. Malignancy arises from repeated cycles of necrosis and regeneration with the ultimate emergence of hyperplasia and then neoplasia. Metabolites of TCE, trichloroacetic acid and dichloroacetic acid, mediate this toxic effect of TCE. These chloroacetic acids also induce similar lesions in rodents given high doses of the medicine, chloral hydrate. Human epidemiologic data show no increase in mortality or malignancy from substantial chronic exposure to trichloroethylene. Chlorination of drinking water produces much higher levels of chloroacetic acids than could be obtained from metabolizing TCE under current regulations. We conclude that the assumptions underlying current regulations are not applicable to TCE. Instead of a straight-line extrapolation model, a threshold model may be more appropriate. The data suggest that it is possible to increase substantially the allowable trichloroethylene in drinking water without increasing health hazards.

Animals↗
PubMed1995

Renal tumorigenicity of 1,1-dichloroethene in mice: the role of male-specific expression of cytochrome P450 2E1 in the renal bioactivation of 1,1-dichloroethene.

1,1-Dichloroethene is used as intermediate in the manufacture of polymers. In male mice, 1,1-dichloroethene caused renal tumors after inhalation. Renal tumors were not observed in female mice or in both sexes of rats. We investigated the metabolic basis for the species- and sex-specific nephrotoxicity and tumorigenicity of 1,1-dichloroethene. Kidney microsomes from male mice biotransformed 1,1-dichloroethene to chloroacetic acid; the amounts of chloroacetic acid formed were dependent on the hormonal status of the animals and correlated well with the ability of kidney microsomes to oxidize p-nitrophenol and chlorozoxazone, specific substrates for cytochrome P450 2E1. In kidney microsomes from naive females, significantly lower rates of oxidation of 1,1-dichloroethene, p-nitrophenol, and chlorozoxazone were observed; oxidation could be induced by testosterone. With a rabbit anti-rat liver cytochrome P450 2E1 antibody, a cross-reactive protein was detected in male mouse kidney microsomes with a molecular weight very similar to that of rat liver cytochrome P450 2E1; the expression of this protein was regulated by testosterone and correlated well with the ability of the microsomes to oxidize p-nitrophenol, chlorozoxazone, and 1,1-dichloroethene. When the relative cytochrome P450 2E1 contents of renal microsomes of male mice from different strains were compared, differences in the expression of cytochrome P450 2E1 were observed. Moreover, nephrotoxicity in Swiss-Webster mice after inhalation of 1,1-dichloroethene was observed only in males and testosterone-treated females, but not in naive females. In kidney microsomes obtained from both sexes of rats and in six samples of human kidney (male donors), no p-nitrophenol oxidase activity was detected. These data suggest that cytochrome P450 2E1 or a P450 enzyme with very similar molecular weight, substrate specificities, and immunological properties is expressed only in male mouse kidney and bioactivates 1,1-dichloroethene.

Acetates↗
PubMed1982

In vitro differentiation of rat peritoneal macrophages into mast cells: an enzymecytochemical study.

Under special culture conditions, rat peritoneal mononuclear phagocytes have previously been shown to transform into typical mast cells, based on their histamine contents, the increase of their membrane IgE-receptors, and the development of metachromatic, electron-dense cytoplasmic granules. In the present investigation, the enzyme-cytochemical characteristics of these cells were examined prior to and during culture. The peritoneal macrophages were found to have strong paranuclear activity of nonspecific esterases and acid hydrolases, while they were negative for peroxidase and chloroacetate esterase. During culture, two main changes in enzyme activity were observed within all the cells: (1) Paranuclear activity was lost in favour of granular enzyme activity throughout the cytoplasm, and (2) chloroacetate esterase appeared in cultured cells and developed a strong granular activity. These findings are consistent with the macrophage nature of the seeded cells and their development into mast cells during culture. They give support to the theory that mast cells originate from the monocyte-macrophage lineage.

Animals↗
PubMed1990

Immunohistochemical differential diagnosis of granulocytic sarcomas and malignant lymphomas on formalin-fixed material.

A panel of monoclonal antibodies (anti-CD45 [common leukocyte antigen], Ki-B3, L26, MT1, UCHL1, anti-CD15 [X-hapten], anti-neutrophil granule protein elastase [NP57]), anti-lysozyme, and the naphthol-ASD-chloroacetate reaction were applied to two cases of granulocytic sarcoma (GS) for evaluation of their utility in differentiating GS from malignant lymphoma. Lysozyme and naphthol-ASD-chloroacetate esterase were found to be the most reliable markers for detection of the myeloid nature of the tumour cells. GS infiltrated solely the mucosa of the nasal cavity in one case, while in the other it involved both the nasal cavity and maxillary sinus with simultaneous eruptions on the skin of the trunk. In both cases, peripheral blood and bone marrow findings were inconspicuous at the time of diagnosis of GS.

Child↗
PubMed1983

[Enzyme activity of isolated leukocyte populations. II. Cytochemical and zymographic studies of cadaver blood].

Blood was taken from the femoral vein of 17 autopsied cadavers with different diagnoses and postmortal intervals (10-120 h). The granulocytes and lymphocytes were isolated with routine methods. The cell suspensions were subject to morphologic, enzyme-cytochemical (naphthol AS-D chloroacetate esterase) and electrophoretic (PGM1, PGM3, GOTM, PEPA, MEM, FUCA) investigations. The following results were obtained: Erythrocyte-free cell suspensions are only found during short postmortal intervals; Isolation of pure lymphocytes from cadaver blood using the described method is only possible very early in the postmortal interval (within 10 h); The isolated granulocytes contain an impressively high percentage of eosinophilic granulocytes; The percentage of naphthol AS-D-chloroacetate esterase-positive granulocytes is considerably lower in stored, conserved blood than in blood smears; Identification of the above mentioned enzymes from isolated granulocytes from all cadavers is possible by electrophoresis.

Enzymes↗
PubMed1975

The biological fate in rats of vinyl chloride in relation to its oncogenicity.

The main eliminative route for [14C]vinyl chloride after oral, i.v. or i.p. administration to rats is pulmonary; both unchanged vinyl chloride and vinyl chloride-related CO2 are excreted by that route and the other [14C] metabolites via the kidneys. After intragastric administration, pulmonary output of unchanged vinyl chloride is proportional to the logarithm of reciprocal dose. Excretion patterns after i.v. and i.p. injections are predictable from the characteristics of excretion following oral administration. Pulmonary excretion of unchanged vinyl chloride after oral dosing is complete within 3-4 h, but pulmonary elimination of CO2 and renal excretion of metabolites occupies 3 days. In comparison, 99% of a small i.v. dose is excreted unchanged within 1 h of injection; 80% within 2 min. The rate of elimination of a single oral doses of [14C]vinyl chloride is uninfluenced by up to 60 days' chronic dosing with the unlabelled substance. The distribution volume of vinyl chloride as displayed by whole-animal autoradiography agrees with deductions from excretion data. Small localization of 14C in the para-auricular region of appropriate sections occurs in sectioned tubules, belonging possibly to the Zymbal glands. Biotransformation of vinyl chloride into S-(2-chloroethyl) cysteine and N-acetyl-S-(2-chloroethyl) cysteine occurs through addition of cysteine, and biotransformation into: (i) chloroacetic acid, thiodiglycollic acid and glutamic acid, and (ii) into formaldehyde (methionine, serine), CO2 and urea is explicable in terms of an associative reaction with molecular O2 involving a singlet oxygen bonded transition state in dynamic equilibrium with a cyclic peroxide ground state. There is no evidence for chloroethylene oxide formation. Thiodiglycollic acid is the major metabolite of chloroacetic acid in rats; more than 60% of the dose. The interaction of vinyl chloride and of its primary metabolites with the intermediates of mammalian metabolism is discussed in relation to the oncogenicity of that substance.

Acetates↗
PubMed1996

Promotion by dichloroacetic acid and trichloroacetic acid of N-methyl-N-nitrosourea-initiated cancer in the liver of female B6C3F1 mice.

Hepatic tumor promoting activity was determined for dichloroacetic acid (DCA) and trichloroacetic acid (TCA) in female B6C3F1 mice initiated on day 15 of age with 25m/kg N-methyl-N-nitrosourea (MNU). The mice were administered the chloroacetic acids in drinking water starting at 7 weeks of age and continuing until sacrificed 31 or 52 weeks later. Both chloroacetic acids promoted MNU-initiated foci and tumors, however their concentration-response relationships differed being exponential and linear for DCA or TCA, respectively. Lesions promoted by DCA but not by TCA, regressed upon termination of exposure at 31 weeks. Foci and tumors promoted by DCA were eosinophilic and contained glutathione S-transferase-pi(GST-pi), while TCA promoted basophilic tumors lacking GST-pi. Hence, tumor promotion by DCA and TCA appeared to differ both with respect to their concentration-response relationships and to the characteristics of precancerous lesions and tumors.

Animals↗
PubMed2005

Preparation of carboxymethyl chitosan in aqueous solution under microwave irradiation.

Carboxymethyl chitosan was prepared by reacting chitosan with chloroacetic acid in water under microwave irradiation. The effect of the reaction conditions was investigated and optimal conditions were identified. The influence of mass ratio of chloroacetic acid to chitosan, microwave power and pH on the degree of substitution or intrinsic viscosity were further studied. The degree of substitution of the carboxymethyl chitosan synthesized exceeded 0.85.

Acetates↗
PubMed2004

The ecological effects of trichloroacetic acid in the environment.

Trichloroacetic acid (TCAA) is a member of the family of compounds known as chloroacetic acids, which includes mono-, di- and trichloroacetic acid. The significant property these compounds share is that they are all phytotoxic. TCAA once was widely used as a potent herbicide. However, long after TCAA's use as a herbicide was discontinued, its presence is still detected in the environment in various compartments. Methods for quantifying TCAA in aqueous and solid samples are summarized. Concentrations in various environmental compartments are presented, with a discussion of the possible formation of TCAA through natural processes. Concentrations of TCAA found to be toxic to aquatic and terrestrial organisms in laboratory and field studies were compiled and used to estimate risk quotients for soil and surface waters. TCAA levels in most water bodies not directly affected by point sources appear to be well below toxicity levels for the most sensitive aquatic organisms. Given the phytotoxicity of TCAA, aquatic plants and phytoplankton would be the aquatic species to monitor for potential effects. Given the concentrations of TCAA measured in various soils, there appears to be a risk to terrestrial organisms. Soil uptake of TCAA by plants has been shown to be rapid. Also, combined uptake of TCAA from soil and directly from the atmosphere has been shown. Therefore, risk quotients derived from soil exposure may underestimate the risk TCAA poses to plants. Moreover, TCE and TCA have been shown to be taken up by plants and converted to TCAA, thus leading to an additional exposure route. Mono- and di-chloroacetic acids can co-occur with TCAA in the atmosphere and soil and are more phytotoxic than TCAA. The cumulative effects of TCAA and compounds with similar toxic effects found in air and soil must be considered in subsequent terrestrial ecosystem risk assessments.

Animals↗
PubMed1977

Synthesis and anti-herpes simplex activity of analogues of phosphonoacetic acid.

The synthesis of monoesters (P and C) of phosphonoacetic acid (PA) is given. The carboxyl esters were prepared by two methods: the reaction of chloroacetates with tris(trimethylsilyl) phosphite, followed by hydrolysis; and by the acid-catalyzed esterification of PA with the appropriate alcohol. P-Monoesters of PA were prepared either by the reaction of alkyl[bis(trimethylsilyl)] phosphite with benzyl chloroacetate followed by deprotection or by the reaction of dimethylphenyl phosphite with benzyl bromoacetate followed by hydrogenolysis. Three aryl- (alkyl-)phosphinic acid derivatives are reported. The above compounds were evaluated for anti-herpes activity against HSV-induced DNA polymerase and in animals infected with herpes dermatitis.

Acetates↗
PubMed2002

Synthesis of optically active vicinal fluorohydrins by lipase-catalyzed deracemization.

Three microbial lipases have been used to deracemize trans-2-fluorocycloalkanols 2 both by hydrolysis of the corresponding acetates 3 or chloroacetates 4 and by esterification of the fluorohydrins 2 using vinyl acetate and vinyl chloroacetate, respectively. Pseudomonas cepacia lipase was the most selective for the six- and the seven-membered-ring compounds, while the lipase from Candida rugosa was most useful for the eight-membered-ring compounds. Both lipases transform the (R)-enantiomers preferentially. In contrast the lipase from Candida antarctica hydrolyzed the esters of trans-2-fluorocyclohexanol 2a and esterified the fluorohydrin itself with very low enantiopreference for the (R)-isomers. The seven- and the eight-membered ring esters and the corresponding fluorohydrins were also transformed with low, but reverse, enantioselectivity.

Acetates↗
PubMed2006

Magnesium bistrifluoromethanesulfonimide as a new and efficient acylation catalyst.

Magnesium bistrifluoromethanesulfonimide catalyzed the acetylation of phenols, alcohols, and thiols under solvent-free conditions at room temperature and in short times. Electron-deficient and sterically hindered phenols provided excellent yields. The catalyst was found to be general for acylation with other anhydrides, such as propionic, isobutyric, pivalic, chloroacetic, and benzoic anhydrides. The rate of acylation was influenced by the electronic and steric factors associated with the anhydride. The reaction with less electrophilic anhydrides (e.g., chloroacetic and benzoic anhydrides) required higher temperature (approximately 80 degrees C). Chemoselective acetylation, pivalation, and benzoylation took place with acid-sensitive alcohols without any competitive dehydration/rearrangement.

Acetylation↗
PubMed1983

Cytochemical comparison of immunologically characterized human leukaemia/lymphoma cell lines representing different levels of maturation.

Forty-seven human leukaemia/lymphoma cell lines belonging to myelocytic, monocytic, non-T/non-B, T-, and B-lineage and representing different levels of maturation as well as fresh cells from normal and leukaemic subjects were examined for immunological markers and cytochemically for acid phosphatase, alkaline phosphatase, alpha-naphthyl acetate esterase (pH 5.8 and 8.0), alpha-naphthyl butyrate esterase (pH 5.8 and 8.0), non-specific esterase, chloroacetate esterase, chymotrypsin-like protease, deoxyribonuclease II, beta-glucuronidase, sudan black, and periodic acid Schiff's staining. Strong sudan black, nonspecific esterase, and chloroacetate esterase reaction was obtained only for myelocytic and monocytic cell lines with the reaction intensity increasing progressively in more mature cells. Focal acid phosphatase reaction like T-ALL was found in all T-ALL cell lines, whereas myeloid/monocytoid lines had semicircular distribution and B-cell lines cytoplasmic distribution of activity. Acid phosphatase activity appeared to decline with maturation along both myeloid and T-cell lineage. High activity of alpha-naphthyl acetate esterase and alpha-naphthyl butyrate esterase both at pH 5.8 and 8.0 and of beta-glucuronidase was found in myeloid/monocytoid lines although both B- and T-cell lines in contrast to peripheral blood B-cells also had significant esterase activity. alpha-Naphthyl butyrate esterase activity declined with increasing cell maturation along myeloid lineage. Except for weak activity in two B-cell lines alkaline phosphatase was not detected in any cell lines. Monocyte esterase activity was inhibited by sodium fluoride whereas acid phosphatase, only from hairy cell leukaemia line, was resistant to L-tartarate. Although periodic acid Schiff's staining could not distinguish myeloid, T-, B-, or non-T/non-B cell lines it gave characteristic reaction (large number of coarse granules against a clear background forming a ring around the nucleus) with erythroblastic leukaemia cell line and along myeloid series its intensity increased in more mature cells. Deoxyribonuclease II and chymotrypsin-like protease staining were not discriminatory. The results of this study show that cytochemical staining characteristics of various leukaemia/lymphoma cell lines are comparable to those of corresponding cells from patients and that the intensity and pattern of expression of these activities are related to cell type and degree of cell maturation. These studies give further credence to the use of these cell lines in cell differentiation, differential drug cytotoxicity, and many other studies.

Cell Line↗