Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Crotonates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed1992

Monitoring and assessment of mercury pollution in the vicinity of a chloralkali plant. IV. Bioconcentration of mercury in in situ aquatic and terrestrial plants at Ganjam, India.

In situ aquatic and terrestrial plants including a few vegetable and crop plants growing in and around a chloralkali plant at Ganjam, India were analyzed for concentrations of root and shoot mercury. The aquatic plants found to bioconcentrate mercury to different degrees included Marsilea spp., Spirodela polyrhiza, Jussiea repens, Paspalum scrobiculatam, Pistia stratiotes, Eichhornia crassipes, Hygrophila schulli, Monochoria hastata and Bacopa monniera. Among wild terrestrial plants Chloris barbata, Cynodon dactylon, Cyperus rotundus and Croton bonplandianum were found growing on heavily contaminated soil containing mercury as high as 557 mg/kg. Analysis of mercury in root and shoot of these plants in relation to the mercury levels in soil indicated a significant correlation between soil and plant mercury with the exception of C. bonplandianum. Furthermore, the tolerance to mercury toxicity was highest with C. barbata followed by C. dactylon and C. rotundus, in that order. The rice plants analyzed from the surrounding agricultural fields did not show any significant levels of bioconcentrated mercury. Of the different vegetables grown in a contaminated kitchen garden with mercury level at 8.91 mg/kg, the two leafy vegetables, namely cabbage (Brassica oleracea) and amaranthus (Amaranthus oleraceous), were found to bioconcentrate mercury at statistically significant levels. The overall study indicates that the mercury pollution is very much localized to the specific sites in the vicinity of the chloralkali plant.

Environmental Monitoring↗
PubMed1993

Complete oxidation of benzoate and 4-hydroxybenzoate by a new sulfate-reducing bacterium resembling Desulfoarculus.

A new sulfate-reducer "strain SAX" was isolated from an anaerobic marine sediment [Saxild, Denmark]. The isolate was a gram-negative, motile and non-spore-forming rod which sometimes appeared as a curved rod. Strain SAX differed from all described Desulfovibrio-, Desulfobotulus- and Desulfoarculus-species by the ability to degrade aromatic compounds such as benzoate, 4-hydroxybenzoate and phenol completely to CO2. Electron donors used included lactate, pyruvate, malate, fumarate, crotonate and butyrate, while pyruvate was fermented in the absence of an external electron acceptor. Sulfate, thiosulfate or sulfite served as electron acceptors with benzoate as the donor, while nitrate and nitrite did not. The sulfate-reducing bacterium required vitamins and NaCl-concentrations of about 20 g/l. The optimum temperature for growth of strain SAX was 30 degrees C and the optimum pH value was 7.3. The DNA base composition was 62.4 mol% G+C. The strain possessed cytochrome c3, but no desulfoviridin. On the basis of these characteristics and because strain SAX could not be ascribed to any of the existing species therefore assignment as a new species to the genus Desulfoarculus was suggested.

Benzoates↗
PubMed1990

Clostridium homopropionicum sp. nov., a new strict anaerobe growing with 2-, 3-, or 4-hydroxybutyrate.

From anoxic sewage sludge a new strictly anaerobic, spore-forming bacterium was isolated with 2-hydroxybutyrate as sole substrate. 2-, 3-, and 4-hydroxybutyrate, 4-chlorobutyrate, crotonate, vinylacetate, and pyruvate were fermented to acetate and butyrate. Fructose was converted to acetate, butyrate, butanol, and H2. Lactate and acrylate were fermented to acetate and propionate. Cells pregrown with lactate fermented 2-hydroxybutyrate to butyrate, propionate and acetate. No inorganic electron acceptors were reduced. The DNA base ratio was 32.0 +/- 1.0 mol% and was similar to that of Clostridium propionicum, which was determined to be 35.3 +/- 0.5 mol%. Strain LuHBu1 is described as type strain of a new species, Clostridium homopropionicum sp. nov. Another isolate obtained from marine sediment degraded 2- and 3-hydroxybutyrate to acetate and butyrate and was in some respects similar to the known species Ilyobacter polytropus.

Acetates↗
PubMed1975

On the active principles of the spurge family. III. Skin irritant and cocarcinogenic factors from the caper spurge.

The toxic and irritant principles of the seed oil and of the latex of the caper spurge (Euphorbia lathyris L.) were isolated together with several non irritants of similar chemical structure. From the seed oil two irritant Euphorbia factors L5 and L6 and from the latex a mixture of irritant Euphorbia factors were obtained. Euphorbia factor L5 was identified as 3-hexadecanoate of the new tetracyclic, poly-functional diterpene parent alcohol ingenol. Euphorbia factor L6 most probably is the 3-tetradeca-2,4,6,8,10-penta-enoic acid ester of ingenol. The mixture of Euphorbia factors was shown to contain esters of ingenol and of 16-hydroxy-ingenol, respectively, each containing a long chain unsaturated fatty acid, most probably in 3-position. The non irritants from the seed oil comprise ingenol-20-hexadecanoate (compound L4) and several esters of macrocyclic diterpenes of the new lathyrol type (compounds L1-L3, L8, and possibly L7). Compound L4 is a positional isomer of Euphorbia factor L5 and most probably an artefact formed during the isolation procedure. The macrocyclic diterpenes are of interest as possible intermediates in the biogenesis of tetracyclic diterpene parents of cocarcinogenic esters. The parent alcohols ingenol and 16-hydroxy-ingenol are inactive irritants. As compared to croton oil factor A1 (TPA), Euphorbia factor L5 exhibits about 1/10 of its irritant activity on the ear and about 1/10 of its cocarcinogenic activity on the back skin of mice. As an irritant Euphorbia factor L6 shows about 1/5 of the activity of A1. Structure/activity relationships of ingenol and phorbol esters and the possible role of cocarcinogens of plant origin as second order carcinogenic risk factors are discussed.

Animals↗
PubMed1980

Granuloma pouch assay for mutagenicity testing.

The Granuloma Pouch Assay (GPA) is an animal model in which mutagenic and carcinogenic effects of a testcompound can be detected in rapidly dividing fibroblasts of a granulation tissue in adult male rats. Growth of this tissue was initiated with a small amount of croton oil at the inside wall of a subcutaneous air pouch on the back of the animals. The test compound can be injected either into the pouch (local) or administered by systemic routes. Alkali labile DNA-lesions, chromosome aberrations, sister chromatid exchanges, point mutations and tumor development in situ were determined. The comparison of mutation frequencies after local and systemic administration of testcompounds, provide an estimation of the pharmacokinetic characteristics and the mutagenic potency of the chemical. The local application route allows the detection of locally active mutagens and of compounds which require activation by P-448 dependent mono-oxygenases. Liver mediated proximate metabolites are detectable when they are transformed into ultimate carcinogens in extrahepatic cells whereas chemicals with a strong organ specific activity are not.

Animals↗
PubMed1992

Agents that cause enlargement of sebaceous glands in hairless mice. I. Topical substances.

We have developed a simple murine model to measure the effects on sebaceous glands of a variety of substances commonly found in topical formulations. Applications (0.2 ml) were made daily to the flanks of hairless albino female mice, for time periods varying from 4 to 9 days. Biopsies, fixed for light microscopy, were stained with H & E. Under x400 magnification, the sebocytes comprising each gland were counted, from which the mean sebocyte count per gland was calculated. Electron micrographs were prepared to evaluate sebum production. The test substances, which included anionic and cationic surfactants, solvents and emulsifiers, almost invariably led to a rapid increase in the sebocyte count, peaking at day 5. Irritating substances, such as croton oil and benzalkonium chloride, had the greatest hyperplasiogenic effect, at least doubling the sebocyte count. Electron micrographs showed large increases in rough endoplasmic reticulum and in sebum droplets. Thus, hyperplasia appears to be a stereotypic response to diverse substances, especially if these have irritancy potential.

Administration, Topical↗
PubMed1978

[Co-carcinogens or modulators of carcinogenesis. New aspects of the etiology of human tumors and of the molecular mechanisms of carcinogenesis].

Within the last 10 years numerous new and typical exogenous cocarcinogens were identified chemically as well as biologically and characterized biochemically as initiation or tumor promoters. They are highly irritant diterpene esters of plant origin. Promoters of this type were recently detected also in the Euphorbiacea Croton flavens L., the multiple use of which for stimulants according to local habits was previously held responsible for the unusually high rate of esophageal cancer on Curacao. This detection confirms for the first time that in the etiology of human cancer besides solitary carcinogens (first-order carcinogenic risk factors) also cocarcinogens of the promoter type have to be considered (second-order carcinogenic risk factors). -- The active principles of the diterpene ester type are the strongest promoters known so far; they are noninitiators and nonmutagens. Of the manyfold biochemical activities of these promoters the three most actual are: the TPA molecule does not require activation by metabolic alteration, it releases very rapidly prostaglandin E2 from cellular membranes and it activates latent DNA-viral genoms.

Animals↗
PubMed1978

Reisolation of the carbon monoxide utilizing hydrogen bacterium Pseudomonas carboxydovorans (Kistner) comb. nov.

From enrichment cultures four carbon monoxide utilizing bacteria were isolated; strain OM5 isolated from waste water was studied in detail. The cells are Gram-negative, slightly curved rods, motile by a single subpolarly inserted flagellum. The colonies are smooth, translucent and not slimy. The cells are able to grow autotrophically in mineral medium under an atmosphere of 40% CO, 5% O2 and 55% N2 at a doubling time of 20h (30 degrees C) or of 85% H2, 5% O2 and 10% CO2 at a doubling time of 7h. Heterotrophic growth occurred on organic acids such as acetate(td = 8h), pyruvate(td = 8h), lactate, crotonate, malate, succinate (td = 8h), formate (td = 35h) and glyoxylate as substrates. The enzyme system for carbon monoxide utilization is formed only during growth on CO; hydrogenase is present in cells grown on CO or on H2 + CO2 as well as grown on pyruvate. The rate of oxygen reduction by intact CO-grown cells is 3.7-fold higher in the presence of hydrogen than in the presence of carbon monoxide. During growth the stoichiometry of gas uptake was 6.1 CO + 2.8 O2 + H2O leads to CH2O +5.1 CO2. For the new isolate the name Pseudomonas carboxydovorans (Kistner) comb. nov. has been proposed.

Carbon Monoxide↗
PubMed1982

On the active principles of the spurge family (Euphorbiaceae). IV. Skin irritant and tumor promoting diterpene esters from Euphorbia ingens E.Mey.

The irritant and tumor-promoting principles of the latex of Euphorbia ingens E. Mey have been isolated together with several nonirritant compounds. The Euphorbia factors I1, I5, and I6 are esters of ingenane-type poly-functional diterpene alcohols. Euphorbia factor I1 is characterized as the 3-hexadecanoate of the polyfunctional parent alcohol ingenol and Euphorbia factor I6 as the 3-deca-2.4.6-trienoic acid ester of ingenol. Euphorbia factor I5 is the 16-angelate-3-deca-2.4.6-trienoate of 16-hydroxyingenol. Nonirritant diterpenes of the latex are I2, the ingenol-20-hexadecanoate - an isomer of Euphorbia factor I1 - and I4, the 3.7.12-triacetate-8-nicotinate of the macrocyclic lathyrane-type polyfunctional diterpene alcohol ingol. The diterpene alcohols ingenol and 16-hydroxyingenol are inactive as irritants and tumor promoters of mouse skin. Compared to croton oil factor A1 (TPA), the Euphorbia factor I1 exhibits about 1/10 of the irritant and tumor-promoting activity in mouse skin. I1 shows no reasonable tumorigenic activity. Compared with I1, Eupohorbia factors I5 and I6 are more potent irritants and less potent tumor promoters.

Animals↗
PubMed1982

Cutaneous sensitivity to ultraviolet light and chemical irritants.

This investigation examines the relationship between the sun sensitivity of human skin and its response to chemical irritants. Forty-four Caucasoid subjects with normal back skin were studied. The minimal erythema dose (MED) was determined with the sunburning spectrum of a high-pressure mercury lamp. Cutaneous irritability was quantified using a series of seven irritants of different chemical structure, solubility, and concentrations. The response was either expressed as a threshold value of exposure time (ammonium hydroxide, sodium hydroxide) or was graded after a standard exposure in intensity of whealing (dimethyl sulphoxide) or erythema (sodium lauryl sulphate, quaternium 1, croton oil, kerosene). A significant correlation between the MED and the response to all seven primary irritants was found. The relationship was better for water-soluble irritants than for lipid-soluble ones. Despite marked individual variations the determination of the MED is suggested as a valuable tool in identifying hyperirritable skin. Skin typing based on complexion and sunburn history proved to be less reliable.

Adolescent↗
PubMed1985

Impaired histamine metabolism in the Arthus reaction induced in guinea-pig skin.

The activities of two histamine-metabolizing enzymes, histamine-N-methyltransferase (HMT) and diamine oxidase (DAO), were examined in various types of experimentally induced cutaneous inflammations in guinea pigs. In intact guinea-pig skin, the specific activities of HMT and DAO were 24.8 +/- 1.7 pmol/min per milligram of protein or 0.930 +/- 0.097 pmol/min per milligram of the wet weight of skin specimen, and 6.0 +/- 0.7 pmol/min per milligram of protein or 0.189 +/- 0.011 pmol/min per milligram of the wet weight, respectively. Both enzyme activities were markedly reduced in skin lesions of the Arthus reaction (P less than 0.005), while those in dinitrochlorobenzene allergic dermatitis, croton-oil dermatitis, and the intact areas in Arthus-reaction-induced animals were almost within the normal limits. The activity of HMT decreased linearly with time from the onset of the Arthus reaction, reaching about 20% of the control activity at 48 h; the activity of DAO decreased even from the early stages of the reaction, and this decrease continued throughout first 48 h of the reaction. These results suggest that impaired histamine metabolism in the skin lesions of the reaction plays a distinct role in the formation and development of the Arthus reaction.

Amine Oxidase (Copper-Containing)↗
PubMed1993

Role of electron-donating cosubstrates in the anaerobic biotransformation of chlorophenoxyacetates to chlorophenols by a bacterial consortium enriched on phenoxyacetate.

A bacterial consortium that anaerobically mineralized phenoxyacetate, with transient production of phenol as an intermediate, was obtained from a methanogenic aquifer site near the Norman, OK municipal landfill. This consortium was able to convert the eight halogenated chlorophenoxyacetates tested to the corresponding chlorophenols. The chlorophenols were not subsequently metabolized. The addition of reduced substrates increased the rate of degradation of all chlorophenoxyacetates, with 78% of mono- and di-chlorinated substrates being transformed to chlorophenols in butyrate-amended cultures, compared to less than 37% transformed in unsupplemented cultures. Butyrate increased the transformation of 2,4,5-trichlorophenoxyacetate from 10% to 20%. An experiment evaluating the effects of several compounds on the side-chain cleavage reaction of 3-chlorophenoxyacetate showed that addition of compounds which readily act as hydrogen donors (butyrate, crotonate, ethanol, propionate, and hydrogen) resulted in 2 to 5 times the amount of 3-chlorophenoxyacetate transformed compared to controls with no amendment, formate had a slight stimulatory effect, and acetate and methanol had no effect. Butyrate addition also increased the rate of phenoxyacetate degradation, resulting in transient phenol accumulation not observed in butyrate-unamended controls. These results support the hypothesis that the side-chain cleavage of phenoxyacetate is a reductive process that is stimulated by the oxidation of reduced cosubstrates.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1995

Localization of the enzymes involved in H2 and formate metabolism in Syntrophospora bryantii.

Cell-free extracts of crotonate-grown cells of the syntrophic butyrate-oxidizing bacterium Syntrophospora bryantii contained high hydrogenase activities (8.5-75.8 mumol.min-1mg-1 protein) and relatively low formate dehydrogenase activities (0.04-0.07 mumol.min-1 mg-1 protein). The KM value and threshold value of the hydrogenase for H2 were 0.21 mM and 18 microM, respectively, whereas the KM value and threshold value of the formate dehydrogenase for formate were 0.22 mM and 10 microM, respectively. Hydrogenase, butyryl-CoA dehydrogenase and 3-OH-butyryl-CoA dehydrogenase were detected in the cytoplasmic fraction. Formate dehydrogenase and CO2 reductase were membrane-bound, likely located at the outer aspect of the cytoplasmic membrane. Results suggest that during syntrophic butyrate oxidation H2 is formed intracellularly while formate is formed at the outside of the cell.

Aldehyde Oxidoreductases↗
PubMed1991

The severity of irritant contact dermatitis in various strains of mice correlates with endothelial expression of migration inhibitory factor (MIF).

Irritant contact dermatitis to croton oil in BALB/cByJ, C57Bl/6J and six recombinant inbred CxB strains of mice was investigated in relation to variations in endothelial migration inhibitory factor (MIF) reactivity. MIF has been shown to be a mediator of cellular immunity and operates as a differentiation signal inducing an inflammatory type of macrophage. The intensity of the ear swelling response reached a maximum 8 h after induction of contact dermatitis, with highest values in BALB/cByJ and CxB4/ByAH mice and weak reactions in CxB2/ByAE, CxB7/ByAK, C57Bl/6J and CxB1/ByAD mice. After the same time period (8 h) cryostat sections were immunostained for capillary endothelium expressing MIF. The most pronounced MIF expression was observed in BALB/cByJ mice, and CxB4/ByAH mice showed intermediate reactions and the other strains weak reactions. Endothelial MIF expression correlated well with the intensity of ear swelling (Pearson's correlation coefficient 0.82). Patterns of endothelial MIF expression in recombinant inbred strains suggest that endothelial MIF expression is not under the control of a single gene. Our data support the hypothesis that endothelial MIF expression plays a prominent role in inflammatory events and correlates with the severity of inflammation.

Animals↗
PubMedDate not supplied

The granuloma pouch: an in vivo model for pharmacokinetic and chemotherapeutic investigations. I. Biochemical and histological characterization.

The "granuloma pouch" model in rats was evaluated on the basis of biochemical, haematological and histological factors. Seven days after formation of the pouch following the intramuscular injection of air and a mixture of 1% croton oil in olive oil as an irritant, the pouch was filled by approximately 5 ml of haemorrhagic exudate. Biochemical assessment of the exudate revealed that its main characteristics were increased lactate dehydrogenase levels as well as increased alpha 2- and gamma-globulin fractions. Histological sections of the surrounding tissue showed a typical granulomatous inflammatory response. The granuloma pouch can therefore be characterized as a local, chronic inflammation caused by the creation of a body cavity. The biochemical data of the pouch exudate were compared with those of human wound fluid obtained after surgery; since the values were in very good agreement, it is assumed that the granuloma pouch model reflects the clinical situation in inflamed wound cavities following the extirpation of organs.

Animals↗
PubMed1991

Sexual dimorphism in the defensive secretion of a carabid beetle.

The defensive secretions of male and female Oodes americanus display striking qualitative differences. Altogether 13 carboxylic acids were identified in the secretions of the two sexes. Methacrylic, crotonic, and tiglic acids are produced exclusively by the female; the male lacks these unsaturated components, but produces their saturated analogs. 2-Methylbutyric acid is a major component produced by both sexes. Shared components also include hexanoic, (E)-2-hexenoic, benzoic, and (E)-2-octenoic acid, of which the latter two had not previously been reported from carabid beetles.

Animals↗
PubMed1988

Antiinflammatory, analgesic, and antipyretic activities of methyl 7-butyl-4,5,6,7-tetrahydro-3-methylamino-4,6-dioxo-5-propyl-2H-pyrazol o[3, 4-d]pyrimidine-2-carboxylate (AA-2379), a novel non-acidic agent.

The antiinflammatory, analgesic, and antipyretic activities of methyl 7-butyl-4,5,6,7-tetrahydro-3-methylamino-4,6-dioxo-5-propyl-2H-pyrazolo[ 3, 4-d]pyrimidine-2-carboxylate (AA-2379), a novel non-acidic agent, were examined. 1. AA-2379 had a potent antiinflammatory activity; 3-25 mg/kg, p.o. of the compound inhibited rat carrageenin-, bradykinin-, trypsin-, formalin-, dextran-, and nystatin-induced paw edema; mouse traumatic edema; and rat croton oil pouch inflammation by about 30%. The compound at 25-50 mg/kg, p.o. also inhibited the vascular permeability induced by histamine, serotonin, and bradykinin. 2. AA-2379 had an analgesic activity; the ID50 values in mouse phenylquinone-induced writhing were 10.1 mg/kg, p.o. and the compound at 12.5 mg/kg, p.o. inhibited dog urate arthritis. 3. AA-2379 at 3-10 mg/kg, p.o. showed antipyretic activity in febrile rats and rabbits. 4. AA-2379, at 500 mg/kg, p.o. was not ulcerogenic in rats. 5. These data show that AA-2379 is more active than non-acidic antiinflammatory agents, such as tiaramide and aminopyrine.

Animals↗
PubMed1984

Enhanced skin reactivity to platelet-derived permeability factor (PDPF) and exogenous histamine in an acute phase rabbit model.

Rabbits made acute phase by sub-cutaneous trauma with 2% croton oil (in mineral oil) were tested by intradermal (ID) injection with platelet-granule extracts containing platelet-derived permeability factor (PDPF). Compared with controls, skin reactivity to PDPF was enhanced in acute phase animals 3-7 days post-trauma, a period of acute inflammation as reflected by the occurrence in the circulation of C-reactive protein; maximal skin responses were observed 3-4 days post-trauma. Individual skin sites reached maximum intensity 15 min-1 hour post-ID injection of PDPF and were sensitive to chlorpheniramine maleate, suggesting a major role for histamine. Intradermal injection of histamine revealed that acute phase animals yielded an initially more intense skin reaction, and were markedly less capable of recovering from the effects of histamine. These data suggest that in the acute phase, there exists a heightened and prolonged sensitivity to the action of histamine which can be exploited by pro-inflammatory agents such as PDPF.

Animals↗