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1

Phase II Evaluation of Paclitaxel and Carboplatin in the Treatment of Carcinosarcoma of the Uterus: A Gynecologic Oncology Group Study  

UK PubMed Central (United Kingdom)

PurposePlatinum and taxane compounds have demonstrated activity in uterine carcinosarcoma (malignant mixed Mullerian tumor). Ifosfamide plus paclitaxel is the regimen with established...Full Text Available

2010-06-01

2

Issues in the Pharmacokinetics of Trichloroethylene and Its Metabolites  

UK PubMed Central (United Kingdom)

Much progress has been made in understanding the complex pharmacokinetics of trichloroethylene (TCE). Qualitatively, it is clear that TCE is metabolized to multiple metabolites either locally or into...Full Text Available

2006-09-01

3

Metabolite profiling of sucrose effect on the metabolism of Melissa officinalis by gas chromatography-mass spectrometry  

British Library Electronic Table of Contents (United Kingdom)

The effect of sugar on plant metabolism, which is known to be similar to hormone-like signaling, was metabolomically studied using Melissa officinalis (lemon balm). The metabolite profiles of M. officinalis treated with sucrose were analyzed by gas chromatography-mass spectrometry (GC-MS) and principal component analysis (PCA). A total of 64 metabolites from various chemical classes including alcohols, amines, amino acids, fatty acids, inorganic acids, organic acids, phosphates, and sugars were identified by GC-MS. Three groups treated with different sucrose concentrations were clearly separated by PCA of their metabolite profiles, indicating changes in the levels of many metabolites depending on the sucrose concentration. Metabolite profiling revealed that treatment with a higher sucrose ...

2011-01-01

4

The mechanism of benzene-induced leukemia: a hypothesis and speculations on the causes of leukemia.  

UK PubMed Central (United Kingdom)

An overall hypothesis for benzene-induced leukemia is proposed. Key components of the hypothesis include a) activation of benzene in the liver to phenolic metabolites; b) transport of these metabolites...Full Text Available

1996-12-01

5

Stable Isotope-Coded Quaternization for Comparative Quantification of Estrogen Metabolites by High-Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry  

UK PubMed Central (United Kingdom)

A fast and sensitive LC-ESI-MS method is described for the comparative quantification of 16 estrogen metabolites based on the derivatization of estrogens with a novel derivatizing reagent, N-methyl-nicotinic...Full Text Available

2008-07-15

6

Pharmacology and toxicology of pahayokolide A, a bioactive metabolite from a freshwater species of Lyngbya isolated from the Florida Everglades  

UK PubMed Central (United Kingdom)

The genus of filamentous cyanobacteria, Lyngbya, has been found to be a rich source of bioactive metabolites. However, identification of such compounds from Lyngbya...Full Text Available

2004-12-01

7

Microbial Anaerobic Demethylation and Dechlorination of Chlorinated Hydroquinone Metabolites Synthesized by Basidiomycete Fungi  

UK PubMed Central (United Kingdom)

The synthesis and degradation of anthropogenic and natural organohalides are the basis of a global halogen cycle. Chlorinated hydroquinone metabolites (CHMs) synthesized by basidiomycete fungi and present...Full Text Available

2004-01-01

8

Immediate and residual effects in man of the metabolites of diazepam  

UK PubMed Central (United Kingdom)

1 Immediate and residual effects of diazepam and its metabolites on visuomotor co-ordination have been studied in man. Performance was observed from 10.0-16.0 h after overnight ingestion...Full Text Available

1978-10-01

9

Functional significance of UDP-glucuronosyltransferase (UGT) variants in the metabolism of active tamoxifen metabolites  

UK PubMed Central (United Kingdom)

Tamoxifen (TAM) is a selective estrogen receptor modulator widely used in the prevention and treatment of breast cancer. A major mode of metabolism of the major active metabolites of TAM, 4-OH-TAM...Full Text Available

2009-03-01

10

Development of a physiologically based pharmacokinetic model of trichloroethylene and its metabolites for use in risk assessment.  

UK PubMed Central (United Kingdom)

A physiologically based pharmacokinetic (PBPK) model was developed that provides a comprehensive description of the kinetics of trichloroethylene (TCE) and its metabolites, trichloroethanol (TCOH),...Full Text Available

2000-05-01

11

Calcitriol but no other metabolite of vitamin D is essential for normal bone growth and development in the rat.  

UK PubMed Central (United Kingdom)

To determine the relative importance of different metabolites of vitamin D in bone growth and development, weanling male rat pups suckled by vitamin D-deficient mothers were given either calcitriol...Full Text Available

1984-02-01

12

Anthracenedione Derivatives as Anticancer Agents Isolated from Secondary Metabolites of the Mangrove Endophytic Fungi  

UK PubMed Central (United Kingdom)

In this article, we report anticancer activity of 14 anthracenedione derivatives separated from the secondary metabolites of the mangrove endophytic fungi Halorosellinia sp. (No. 1403)...Full Text Available

14

"1H MR spectroscopy in pediatrics  

International Nuclear Information System (INIS)

Spectral appearance and concentrations of the most prominent metabolites are affected by brain development. This knowledge is essential for the detection of pathological changes in pediatric patients. This paper discusses specific conditions of MR spectroscopic examination of children and the effects of age on MR spectra quality and quantitation of the studied metabolites. Clinical examples show several diseases that are reflected in changes in "1H MR spectra due to pathological alterations in the biochemical pathways of the observed metabolites. Attention is given to the main metabolites such as N-acetylaspartate, creatine/phosphocreatine, cholines, lactate, inositol, etc.

2008-08-01

15

Trinitrotoluene: assessment of occupational absorption during manufacture of explosives.  

UK PubMed Central (United Kingdom)

Trinitrotoluene (TNT) absorption was assessed in groups of workers at two explosives factories by measuring the urinary concentrations of dinitroaminotoluene (DNAT) metabolites. DNAT was detected in...Full Text Available

1986-07-01

16

Transformation of Verapamil by Cunninghamella blakesleeana  

UK PubMed Central (United Kingdom)

A filamentous fungus, Cunninghamella blakesleeana AS 3.153, was used as a microbial model of mammalian metabolism to transform verapamil, a calcium channel antagonist. The metabolites...Full Text Available

2004-05-01

17

Phenolic compounds in ectomycorrhizal interaction of lignin modified silver birch  

UK PubMed Central (United Kingdom)

BackgroundThe monolignol biosynthetic pathway interconnects with the biosynthesis of other secondary phenolic metabolites, such as cinnamic acid derivatives, flavonoids and condensed...Full Text Available

19

Estrogen metabolite ratio: Is the 2-hydroxyestrone to 16?-hydroxyestrone ratio predictive for breast cancer?  

UK PubMed Central (United Kingdom)

Experimental studies have shown that two main estrogen metabolites hydroxylated by CYP1A1 and CYP1B1 in the breast differentially affect breast cell proliferation and carcinogenesis. Although 16α-hydroxyestrone...Full Text Available

20

Decreased serum protein binding of diazepam and its major metabolite in the neonate during the first postnatal week relate to increased free fatty acid levels.  

UK PubMed Central (United Kingdom)

The protein binding of diazepam (D) and its major active metabolite N-desmethyl diazepam (DD) was investigated in vitro in the serum of 14 mothers at birth, 21 foetuses at birth, in 100 neonates between...Full Text Available

1984-01-01

 
 
 
 
21

Determination of microsomal lauric acid hydroxylase activity by HPLC with flow-through radiochemical quantitation  

International Nuclear Information System (INIS)

An assay for the microsomal hydroxylation of lauric acid (LA), based on HPLC with flow-through radiochemical detection, has been developed. Conditions were optimized for resolution and quantitation of three microsomal metabolites of "1"4C-LA, one of which has not been reported previously as a metabolite of LA in mammalian microsomal incubations. These products, 12-(omega)-hydroxy-LA, 11-(omega-1)-hydroxy-LA, and a novel metabolite, 10-(omega-2)-hydroxy-LA, were isolated by HPLC and identified by gas chromatography/mass spectrometry. In the presence of NADPH, the formation of all three metabolites was linear with time and microsomal protein concentration. Hydrogen peroxide also supported the microsomal metabolism of LA, although the ratio of metabolites was substantially different than that produced by NADPH-supported microsomes. Several biochemical probes (metyrapone, ...

22

The metabolism of hexachlorocyclohexanes and pentachlorocyclohexenes in flies and grass grubs  

UK PubMed Central (United Kingdom)

1. γ-Hexachlorocyclohexane, γ-pentachlorocyclohexene and δ-pentachlorocyclohexene were converted by houseflies and grass grubs into metabolites that had chromatographic properties...Full Text Available

1969-06-01

23

The Relationship of Urinary Metabolites of Carbaryl/Naphthalene and Chlorpyrifos with Human Semen Quality  

UK PubMed Central (United Kingdom)

Most of the general population is exposed to carbaryl and other contemporary-use insecticides at low levels. Studies of laboratory animals, in addition to limited human data, show an association between...Full Text Available

2004-12-01

24

TRPV1 in Brain Is Involved in Acetaminophen-Induced Antinociception  

UK PubMed Central (United Kingdom)

BackgroundAcetaminophen, the major active metabolite of acetanilide in man, has become one of the most popular over-the-counter analgesic and antipyretic agents, consumed by millions...Full Text Available

25

Synthesis of deuterated eicosanoids  

Energy Technology Data Exchange (ETDEWEB)

Deuterated lipoxygenase and cyclooxygenase derivatives of eicosatetraenoic acid (arachidonic acid) and their metabolites are indispensable tools for organic trace analysis, biomedical studies, and mechanistic investigations on the corresponding endogenous (unlabelled) eicosanoids. Methods for the preparation of deuterated eicosanoids are reviewed.

1986-03-01

26

Simultaneous and Enhanced Production of Thermostable Amylases and Ethanol from Starch by Cocultures of Clostridium thermosulfurogenes and Clostridium thermohydrosulfuricum  

UK PubMed Central (United Kingdom)

Clostridium thermohydrosulfuricum and Clostridium thermosulfurogenes produced ethanol and amylases with different components as primary metabolites of starch fermentation....Full Text Available

1985-05-01

27

Quantification and deconvolution of asymmetric LC-MS peaks using the bi-Gaussian mixture model and statistical model selection  

UK PubMed Central (United Kingdom)

BackgroundLiquid chromatography-mass spectrometry (LC-MS) is one of the major techniques for the quantification of metabolites in complex biological samples. Peak modeling is one...Full Text Available

28

Pulmonary metabolism of foreign compounds: its role in metabolic activation.  

UK PubMed Central (United Kingdom)

The lung has the potential of metabolizing many foreign chemicals to a vast array of metabolites with different pharmacological and toxicological properties. Because many chemicals require metabolic...Full Text Available

1990-04-01

29

Protein Targets of Reactive Metabolites of Thiobenzamide in Rat Liver In Vivo  

UK PubMed Central (United Kingdom)

Thiobenzamide (TB) is a potent hepatotoxin in rats, causing dose-dependent hyperbilirubinemia, steatosis, and centrolobular necrosis. These effects arise subsequent to and appear to result from...Full Text Available

2008-07-01

30

Plasma binding of disopyramide and mono-N-dealkyldisopyramide.  

UK PubMed Central (United Kingdom)

1 Measuring total plasma levels of disopyramide (DP) and the main metabolite mono-N-dealkyldisopyramide (MND) in patients on maintenance therapy with DP has shown concentrations of MND comparable with...Full Text Available

1982-11-01

31

Physiologically based pharmacokinetic models for trichloroethylene and its oxidative metabolites.  

UK PubMed Central (United Kingdom)

Trichloroethylene (TCE) pharmacokinetics have been studied in experimental animals and humans for over 30 years. Compartmental and physiologically based pharmacokinetic (PBPK) models have been developed...Full Text Available

2000-05-01

32

Nitrogen metabolite repression of nitrate reductase in Neurospora crassa.  

UK PubMed Central (United Kingdom)

The effect of different nitrogen compounds on the induction of reduced nicotinamide adenine dinucleotide phosphate-nitrate reductase was examined in Neurospora crassa. Whereas in the wild-type strain...Full Text Available

1979-03-01

33

Mutagenicity of stemphyltoxin III, a metabolite of Alternaria alternata.  

UK PubMed Central (United Kingdom)

Some common decay organisms of vegetables and ripened fruits are Alternaria species. Even fruits and vegetables kept under refrigeration can be spoiled by Alternaria species because the mold grows at...Full Text Available

1991-01-01

34

Modulation of lipid biosynthesis contributes to stress resistance and longevity of C. elegans mutants  

UK PubMed Central (United Kingdom)

Many lifespan-modulating genes are involved in either generation of oxidative substrates and end-products, or their detoxification and removal. Among such metabolites, only lipoperoxides have the ability...Full Text Available

35

Kinetic studies of preactivated derivatives of cyclophosphamide by "3"1P NMR spectroscopy  

International Nuclear Information System (INIS)

Selected derivatives of cyclophosphamide (CP) metabolites were synthesized and the solution chemistry of each was studied by "3"1P nuclear magnetic resonance (NMR) spectroscopy under a standard set of reaction conditions at physiological pH (7.4) and temperature (37"0C). Complementary "2H and "1"3C NMR spectral data was obtained using isotopically ("2G and "1"3C) enriched CP metabolites. The CP derivatives were synthesized by the ozonolysis of substituted 3-butenyl phosphorodiamidates, and were isolated as analogues of either cis and trans 4-hydroperoxy-CP or aldophosphamide (AP). The relative ratios of the tautomeric species, 4-hydroxy-CP and AP, and their half-lives (T/sub 1/2/) were measured by "3"1P NMR spectroscopy. The influence of CP metabolites on perfused U-937 cells, a CP-sensitive human lymphoma, was observed by high resolution "3"1P NMR spectroscopy. In this manner, it was possible to measure, for the first ...

36

Indole-Diterpene Gene Cluster from Aspergillus flavus  

UK PubMed Central (United Kingdom)

Aflatrem is a potent tremorgenic mycotoxin produced by the soil fungus Aspergillus flavus and is a member of a large structurally diverse group of secondary metabolites known as indole-diterpenes....Full Text Available

2004-11-01

37

Genetic association between the COMT genotype and urinary levels of tea polyphenols and their metabolites among daily green tea drinkers  

UK PubMed Central (United Kingdom)

Available in vitro and animal studies have shown cancer protective effects of tea polyphenols. Recent study suggests a greater protective effect of green tea intake on breast cancer...Full Text Available

38

Field application of a colorimetric method of assaying chloroquine and desethylchloroquine in urine  

UK PubMed Central (United Kingdom)

In a study in western Kenya of malaria-infected adult women who had been treated with chloroquine, we compared the level of chloroquine and its principal metabolite, desethylchloroquine, in urine,...Full Text Available

1988-01-01

39

Fatty Acid- and Retinoid-binding Proteins Have Distinct Binding Pockets for the Two Types of Cargo*  

UK PubMed Central (United Kingdom)

Parasitic nematodes cause serious diseases in humans, animals, and plants. They have limited lipid metabolism and are reliant on lipid-binding proteins to acquire these metabolites from their hosts....Full Text Available

2009-12-18

40

Exploring the Temperature-Stress Metabolome of Arabidopsis1[w  

UK PubMed Central (United Kingdom)

Metabolic profiling analyses were performed to determine metabolite temporal dynamics associated with the induction of acquired thermotolerance in response to heat shock and acquired freezing tolerance...Full Text Available

2004-12-01

 
 
 
 
41

Enhanced Levels of the Aroma and Flavor Compound S-Linalool by Metabolic Engineering of the Terpenoid Pathway in Tomato Fruits1  

UK PubMed Central (United Kingdom)

The aromas of fruits, vegetables, and flowers are mixtures of volatile metabolites, often present in parts per billion levels or less. We show here that tomato (Lycopersicon esculentum...Full Text Available

2001-11-01

42

Dissociation from albumin: a potentially rate-limiting step in the clearance of substances by the liver.  

UK PubMed Central (United Kingdom)

The hepatic uptake rate for certain albumin-bound drugs and metabolites correlates poorly with their equilibrium unbound concentration in the plasma, suggesting that binding equilibrium may not always...Full Text Available

1985-03-01

43

Chemiosmotic model for plant mitochondria  

Energy Technology Data Exchange (ETDEWEB)

A balanced application of chemiosmosis to plant mitochondria is presented. Electron transport carriers are sequenced to achieve proton translocation across the inner membrane. The processes of proton translocation, use, and release are integrated to yield a description of the effective proton gradient available for metabolite transport and ATP synthesis. 27 references, 6 figures.

1983-12-01

44

Characterization of ?-Butyrolactone Autoregulatory Signaling Gene Homologs in the Angucyclinone Polyketide WS5995B Producer Streptomyces acidiscabies?  

UK PubMed Central (United Kingdom)

Organisms belonging to the genus Streptomyces produce numerous important secondary metabolites and undergo a sophisticated morphological differentiation program. In many instances these...Full Text Available

2009-08-01

45

Application of Cryopreserved Human Hepatocytes in Trichloroethylene Risk Assessment: Relative Disposition of Chloral Hydrate to Trichloroacetate and Trichloroethanol  

UK PubMed Central (United Kingdom)

BackgroundTrichloroethylene (TCE) is a suspected human carcinogen and a common ground-water contaminant. Chloral hydrate (CH) is the major metabolite of TCE formed in the liver by...Full Text Available

2006-08-01

46

Analysis of target cell susceptibility as a basis for the development of a chemoprotective strategy against benzene-induced hematotoxicities.  

UK PubMed Central (United Kingdom)

A goal of our research is to identify biochemical factors that underlie the susceptibility of bone marrow cell populations to benzene metabolites so as to develop a mechanistically based chemoprotective...Full Text Available

1996-12-01

47

Adaptations of the Saker-Solomons test: simple, reliable colorimetric field assays for chloroquine and its metabolites in urine.  

UK PubMed Central (United Kingdom)

Two field-adapted colorimetric methods for measuring the antimalarial drug chloroquine in urine are described. Both are modifications of the method of Saker and Solomons for screening urine for phencyclidine...Full Text Available

1989-01-01

48

Confirmatory analysis method for zeranol, its metabolites and related mycotoxins in urine by liquid chromatography-negative ion electrospray tandem mass spectrometry  

Energy Technology Data Exchange (ETDEWEB)

The determination of the banned anabolic substance zeranol and the metabolites taleranol and zearalanone in bovine urine is complicated by the occurrence of the structurally-related mycotoxin zearalenone and the corresponding {alpha}- and {beta}-zearalenol metabolites which possess similar estrogenic properties. A liquid chromatography-negative ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of all six resorcylic acid lactones ('zeranols') in urine samples using deuterium-labelled internal standards. The method was validated as a confirmatory method for bovine urine samples according to new draft EU guidelines and showed good precision and linearity, and CC{alpha} and CC{beta} values of 0.02-0.30 and <1.0 ng ml{sup -1}, respectively. The applicability was demonstrated by comparing the results of an incurred sample with previous results on the same sample obtained by gas ...

2002-11-25

49

Comparison of secondary metabolite production by Penicillium crustosum strains, isolated from Arctic and other various ecological niches.  

Science.gov (United States)

Penicillium crustosum is common in food and feed both in subtropical and temperate regions. Recently, it has also been found occurring frequently in glacier ice, sea ice and sea water of Arctic regions of Svalbard. The aim of the study was to compare isolates of the same fungal species from widely different habitats and geographic regions to see if the nutritional physiology and the profile of secondary metabolites were consistent or depended on the isolation source. All 121 strains examined produced the following families of secondary metabolites: penitrems (100%), roquefortines (100%), terrestric acids (99.2%) and viridicatols (100%), whereas 81 of 83 Arctic isolates additionally produced andrastin A. However, only 8 of 38 non-Arctic isolates produced detectable andrastin A. The quantitative profiles of 96 strains were compared using cluster, principal component and correspondence analyses. There was no clear grouping of Arctic versus ...

2004-12-22

50

Reductive metabolism of the dinitrobenzamide mustard anticancer prodrug PR-104 in mice  

British Library Electronic Table of Contents (United Kingdom)

Purpose PR-104, a bioreductive prodrug in clinical trial, is a phosphate ester which is rapidly metabolized to the corresponding alcohol PR-104A. This dinitrobenzamide mustard is activated by reduction to hydroxylamine (PR-104H) and amine (PR-104M) metabolites selectively in hypoxic cells, and also independently of hypoxia by aldo-keto reductase (AKR) 1C3 in some tumors. Here, we evaluate reductive metabolism of PR-104A in mice and its significance for host toxicity. Methods The pharmacokinetics of PR-104, PR-104A and its reduced metabolites were investigated in plasma and tissues of mice (with and without SiHa or H460 tumor xenografts) and effects of potential oxidoreductase inhibitors were evaluated. Results Pharmacokinetic studies identified extensive non-tumor reduction of PR-104A to t...

2011-01-01

51

Phytoremediation potential of Portulaca grandiflora Hook. (Moss-Rose) in degrading a sulfonated diazo reactive dye Navy Blue HE2R (Reactive Blue 172)  

British Library Electronic Table of Contents (United Kingdom)

Wild and tissue cultured plants of Portulaca grandiflora Hook. have shown to be able to decolorize a sulfonated diazo dye Navy Blue HE2R (NBHE2R) up to 98% in 40h. A significant induction in the activities of lignin peroxidase, tyrosinase and DCIP reductase was observed in the roots during dye decolorization. The wild plants and tissue cultures could independently decolorize and degrade NBHE2R into metabolites viz. N-benzylacetamide and 6-diazenyl-4-hydroxynaphthalene-2-sulfonic acid. A dye mixture and a textile effluent were also decolorized efficiently by P. grandiflora. The phytotoxicity study revealed reduction in the toxicity due to metabolites formed after dye degradation.

2011-01-01

52

New [{sup 99m}Tc]-cytectrene amine compounds as specific brain imaging agents  

Energy Technology Data Exchange (ETDEWEB)

Lipophilic tertiary amines attached to cylcopentadienyl technetium-99m tricarbonyl (cytectrene) have been prepared with high radiochemical yield and purity. Biodistribution studies in mice showed that [{sup 99m}Tc]-cytectrenes, containing in their structure an N-methylpiperidine, were accumulated in the brain up to 2.8% of injected dose with high brain-to-blood ratios at 15 min p.i. They therefore indicate some potential as brain imaging agents. It has to be pointed out that the N-methylpiperidine ester showed similar biological behaviour as the keto derivatives. This indicates that the conversion to polar metabolite(s) via hydrolysis of the ester group - as described for [{sup 99m}Tc]-ECD -is not essential for brain retention. (Author).

1995-02-01

53

New ["9"9"mTc]-cytectrene amine compounds as specific brain imaging agents  

International Nuclear Information System (INIS)

Lipophilic tertiary amines attached to cylcopentadienyl technetium-99m tricarbonyl (cytectrene) have been prepared with high radiochemical yield and purity. Biodistribution studies in mice showed that ["9"9"mTc]-cytectrenes, containing in their structure an N-methylpiperidine, were accumulated in the brain up to 2.8% of injected dose with high brain-to-blood ratios at 15 min p.i. They therefore indicate some potential as brain imaging agents. It has to be pointed out that the N-methylpiperidine ester showed similar biological behaviour as the keto derivatives. This indicates that the conversion to polar metabolite(s) via hydrolysis of the ester group - as described for ["9"9"mTc]-ECD -is not essential for brain retention. (Author).

54

Interconnected project 'Development and testing of a biological monitoring for effects of polycyclic aromatic hydrocarbons on man'  

International Nuclear Information System (INIS)

The research project had the aim to develop a standard for measuring individual, inner stresses from polycyclic aromatic hydrocarbons (PAHs) at work. The employed method was by characterizing PAHs and metabolites of PAHs to be identified in urine with a view to developing a biological monitoring of professionally exposured persons. Using a number of PAHs relevant to work, the following questions were studied in cell culture systems and different animal-experimental models: Which metabolites are formed from the PAHs used in cell culture systems and the different animal-experimental models, and what are their ratios in percent? What percentage of a PAH is excreted by experimental animals in their urine and faeces on the first, second, and third day following different forms of application? What is the scale of the individual range of variation of PAH mass excretion? Are these results transferable to man? (orig.).

1992-01-01

55

Enhanced extraction yields and mobile phase separations by solvent mixtures for the analysis of metabolites in Annona muricata L. leaves  

British Library Electronic Table of Contents (United Kingdom)

The effects of five extraction solvents and their mixtures on the yield of metabolites in crude and fractionated extracts of Annona muricata L. leaves were investigated by direct comparison. Extraction media were prepared using simplex centroid mixtures of ethanol, ethyl acetate, dichloromethane, acetone, and chloroform. The effects of the mobile phase solvent strength and the analysis wavelength on the chromatographic separation were also investigated. Solvent mixtures rather than pure solvents were found to be the most efficient extractors for the different fractions. The results indicated that the mobile phase composed of methanol/acetonitrile/water (26:27:47 v/v/v) was most suitable for the basic fraction analysis at 254 nm, whereas the mobile phase composed of methanol/acetonitrile/wa...

2009-01-01

56

Development of an internet based system for modeling biotin metabolism using Bayesian networks  

British Library Electronic Table of Contents (United Kingdom)

Biotin is an essential water-soluble vitamin crucial for maintaining normal body functions. The importance of biotin for human health has been under-appreciated but there is plenty of opportunity for future research with great importance for human health. Currently, carrying out predictions of biotin metabolism involves tedious manual manipulations. In this paper, we report the development of BiotinNet, an internet based program that uses Bayesian networks to integrate published data on various aspects of biotin metabolism. Users can provide a combination of values on the levels of biotin related metabolites to obtain the predictions on other metabolites that are not specified. As an inherent feature of Bayesian networks, the uncertainty of the prediction is also quantified and reported to...

2011-01-01

57

Comparison of Plasma Antioxidant Levels and Related Metabolic Parameters Between Smokers and Non-smokers  

British Library Electronic Table of Contents (United Kingdom)

The relationship between cigarette smoking and cell damage is complicated, particularly considering the role of oxidative stress. The aim of this study was to identify the relationships among plasma nicotine metabolites, lipophilic antioxidants, and metabolic parameters in smokers and non-smokers. This cross-sectional study recruited 100 subjects who visited the Department of Family Medicine at Kaohsiung Medical University Hospital. Excluding 14 ineligible cases, 46 smokers and 40 non-smokers were enrolled. Plasma nicotine metabolites, lipophilic antioxidants (including retinol, lycopene, a-carotene, b-carotene, d-tocopherol, g-tocopherol and a-tocopherol), related metabolic parameters, and body composition (including height, weight, body mass index, body fat, and waist circumference) were...

2009-01-01

58

Cell-mediated mutagenesis and cell transformation of mammalian cells by chemical carcinogens. [Rats, hamsters  

Science.gov (United States)

We have developed a cell-mediated mutagenesis assay in which cells with the appropriate markers for mutagenesis are co-cultivated with either lethally irradiated rodent embryonic cells that can metabolize carcinogenic hydrocarbons or with primary rat liver cells that can metabolize chemicals carcinogenic to the liver. During co-cultivation, the reactive metabolites of the procarcinogen appear to be transmitted to the mutable cells and induce mutations in them. Assays of this type make it possible to demonstrate a relationship between carcinogenic potency of the chemicals and their ability to induce mutations in mammalian cells. In addition, by simultaneously comparing the frequencies of transformation and mutation induced in normal diploid hamster cells by benzo(a)pyrene (BP) and one of its metabolites, it is possible to estimate the genetic target size for cell transformation in vitro.

1977-01-01

59

Anthracenedione derivatives as anticancer agents isolated from secondary metabolites of the mangrove endophytic fungi.  

Science.gov (United States)

In this article, we report anticancer activity of 14 anthracenedione derivatives separated from the secondary metabolites of the mangrove endophytic fungi Halorosellinia sp. (No. 1403) and Guignardia sp. (No. 4382). Some of them inhibited potently the growth of KB and KBv200 cells, among which compound 6 displayed strong cytotoxicity with IC(50) values of 3.17 and 3.21 microM to KB and KBv200 cells, respectively. Furthermore, we demonstrate that the mechanism involved in the apoptosis induced by compound 6 is probably related to mitochondrial dysfunction. Additionally, the structure-activity relationships of these compounds are discussed. PMID:20479985

2010-04-23

60

Radiotherapy versus surgery in good-risk Ewing's sarcoma. An analysis of the CESS 86-data  

International Nuclear Information System (INIS)

The evaluation of radiotherapy and surgery as exclusive local treatment in comparably selected subgroups of patients with Ewing's sarcoma on the basis of the CESS 86-data. In the German multicenter Ewing's sarcoma study CESS 86, treatment consisted for four 9-week-courses of VACA- or VAIA-chemotherapy plus local therapy. VACA (vincristine, actinomycin D, cyclophosphamide, adriamycin) was given in low-risk extremity tumors with a tumor volume below 100 cm"3. Highrisk patients with central lesions or a tumor volume >100 m"3 received VAIA (ifosfamide instead of cyclophosphamide). Local therapy started after one complete chemotherapy course in week 10. Based on an individual decision in each patient, local therapy was either radical surgery or resection plus postoperative irradiation with 45 Gy or definitive radiotherapy with 60 Gy. Because of poor results with radiotherapy in a preceeding study, it was intended to restrict irradiation to patients with small ...

 
 
 
 
61

Radiation therapy for Ewing's sarcoma: Results from Memorial Sloan-Kettering in the modern era  

International Nuclear Information System (INIS)

Purpose: To evaluate the outcomes of patients with Ewing's sarcoma family of tumors (ESFT) treated with modern radiotherapy techniques with MRI along with optimal chemotherapy. Methods and Materials: The records of all 60 patients with ESFT who received radiation to the primary site between 1990 and 2004 were reviewed. All patients received chemotherapy, including vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide. Radiation was used as the sole modality for local control in 31 patients and was given either before (n = 3) or after surgical resection (n = 26) in the remainder. All patients had MRI and CT scan-based treatment planning, and 43% received intensity-modulated radiation therapy. Radiation doses ranged from 30 Gy to 60 Gy (median, 51 Gy), and 35% received hyperfractionated radiotherapy. Results: Median age was 16 years (range, 2-40 years). Because of selection bias for radiotherapy, the majority of primary tumors were centrally located ...

2006-02-01

62

Studies with 1,2-dithiole-3-thione as a chemoprotector of hydroquinone-induced toxicity to DBA/2-derived bone marrow stromal cells.  

UK PubMed Central (United Kingdom)

Stromal cells from DBA/2 mouse bone marrow have been shown to be susceptible to cytotoxicity induced by several redox-active metabolites of benzene, including hydroquinone (HQ). Treatment with HQ also...Full Text Available

1993-06-01

63

Separation and Measurement of Plant Alkaloid Enantiomers by RP-HPLC Analysis of their Fmoc-Alanine Analogs  

Science.gov (United States)

Plants often synthesize secondary metabolites that are enantiomers. Enantiomers can cause very different physiological responses. Ammodendrine (1) and anabasine (2) are teratogens that can cause congenital malformations in livestock and enantiomeric forms of each have been found in Lupinus spp. an...

64

Response of a non-Hodgkin lymphoma to "6"0Co therapy monitored by 31P MRS in situ  

International Nuclear Information System (INIS)

High quality "3"1P MR spectra (signal to noise ratio (S/N) approximately 18, 15 min acquisition for each spectrum) were consistently obtained with surface coils over a period of 6-week RT. Both transient and steady state alterations in metabolites in response to RT were found in this case. The transient changes occurred during the first 3 hr immediately after the 3rd fractionated RT, these changes include the transient elevation of the PCr resonance, a decrease in PDE and an increase in intracellular pH. The monitoring showed that the metabolites approached steady state approximately 2 hr after the fractionated radiation intervention, suggesting that in vivo MRS can be useful for studying the dynamics of tumor response to RT such as repair of potential lethal damage, growth delay, and reoxygenation etc. The steady-state MR spectra showed the net response to each intervention and can clinically be useful for predicting and measuring the result ...

65

Morphological Instabilities in a growing Yeast Colony Experiment and Theory  

CERN Document Server

We study the growth of colonies of the yeast Pichia membranaefaciens on agarose film. The growth conditions are controlled in a setup where nutrients are supplied through an agarose film suspended over a solution of nutrients. As the thickness of the agarose film is varied, the morphology of the front of the colony changes. The growth of the front is modeled by coupling it to a diffusive field of inhibitory metabolites. Qualitative agreement with experiments suggests that such a coupling is responsible for the observed instability of the front.

1997-01-01

66

Lack of formic acid production in rat hepatocytes and human renal proximal tubule cells exposed to chloral hydrate or trichloroacetic acid  

UK PubMed Central (United Kingdom)

The industrial solvent trichloroethylene (TCE) and its major metabolites have been shown to cause formic aciduria in male rats. We have examined whether chloral hydrate (CH) and trichloroacetic...Full Text Available

2007-02-12

67

LC-MS analysis in the e-beam and gamma radiolysis of metoprolol tartrate in aqueous solution: Structure elucidation and formation mechanism of radiolytic products  

British Library Electronic Table of Contents (United Kingdom)

E-beam and gamma products from the radiolysis of aqueous solutions of (+-)-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of (+-)-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed.

2006-01-01

68

Isomeric prostaglandin F2 compounds arising from prostaglandin D2: a family of icosanoids produced in vivo in humans.  

UK PubMed Central (United Kingdom)

Prostaglandin (PG) D2 has been shown to be transformed by human 11-ketoreductase to 9 alpha,11 beta-PGF2, a biologically active metabolite that is produced in vivo. During the course of developing a...Full Text Available

1988-01-01

69

INTRODUCTION OF ATRAZINE-DEGRADING PSEUDOMONAS SP. STRAIN ADP TO ENHANCE PHYTOREMEDIATION OF ATRAZINE  

Science.gov (United States)

Atrazine (ATR) has been widely applied in the US and Mid Western states. Recently, public health and ecological concerns have been raised about contamination of surface and ground water by ATR and its chlorinated metabolites, due to their toxicity and potential carcinogenic or endocrinology effects....

70

Effect of repeated benzene inhalation exposures on benzene metabolism, binding to hemoglobin, and induction of micronuclei  

International Nuclear Information System (INIS)

Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure ...

71

Besarhanamides A and B from the marine cyanobacterium Lyngbya majuscula  

British Library Electronic Table of Contents (United Kingdom)

Besarhanamides A (1) and B (2) are fatty acid amides purified from the marine cyanobacterium, Lyngbya majuscula, collected from Pulau Hantu, Singapore. The structure determination of these secondary metabolites was carried out using extensive 2D NMR spectral data as well as chemical manipulations including the Marfey's method. In addition, besarhanamide A exhibited moderate toxicity with LD50 at 13mM in the brine shrimp toxicity bioassay.

2008-01-01

72

The efficacy of low-dose radiation therapy and surgical resection for Ewing's sarcoma  

International Nuclear Information System (INIS)

Purpose: To evaluate the effect of low-dose radiation therapy and surgery on local control in patients with Ewing's Sarcoma. Materials and Methods: Between 1979 and 1995 24 patients (ages 4-47) with Ewing's sarcoma were treated with combined modality therapy that included multi agent chemotherapy, surgical resection, and radiation therapy. Twelve patients had metastatic disease at the time of presentation (pleura = 3, lung = 5, bone 4). Tumor location was central in 16 and peripheral in 8. Multi agent chemotherapy consisted of vincristine/actinomycin D/cyclophosphamide/doxorubicin in 19. The same agents with the addition of ifosfamide and etoposide were given in 5. The extent of resection was considered to be radical in 14 and of the 16 patients who received preoperative chemotherapy, 5 were found to have a pathologic complete response. All patients with lung metastases at diagnosis received whole-lung irradiation to 1400 cGy in 10 fractions. Radiation therapy to ...

1996-09-01

73

Second malignancies after treatment for Ewing's sarcoma  

International Nuclear Information System (INIS)

Background: Some former retrospective studies have suggested that patients with Ewing's sarcoma might have a very high risk for developing secondary sarcomas if treated with radiotherapy. We have evaluated the risk of second malignancies (SM) in patients treated in the German Cooperative Ewing's Sarcoma Studies CESS 81 and CESS 86. Materials and methods: From January 1981 through June 1991, a total number of 674 patients was registered in the two multicentric Ewing's sarcoma trials CESS 81 (1981 through 1985) and CESS 86 (1986 through June 1991). The systemic treatment consisted in both studies of a four-drug-chemotherapy (VACA= vincristine, actinomycin D, cyclophosphamide and adriamycin; or VAIA= vincristine, actinomycin D, ifosfamide and adriamycin) and a total number of four courses, each lasting nine weeks, was recommended by the protocol. Local therapy was either complete surgery or surgery plus postoperative radiotherapy with 36-46Gy or definitive ...

74

Cutaneous and subcutaneous Ewing's sarcoma: an indolent disease  

International Nuclear Information System (INIS)

Purpose: The occurrence of extraosseous Ewing's sarcoma (ES) in deep soft tissues has been well described, but cases in which this tumor occurs in a primary cutaneous or subcutaneous site have rarely been reported. The superficial variant may be less aggressive than are the more common bony and deep soft tissue counterparts with an apparently favorable outcome. A retrospective review of patients with cutaneous or subcutaneous ES was conducted to analyze outcome and patterns of failure. Methods and Materials: Between July 1985 and March 1997, 14 patients with cutaneous or subcutaneous ES were treated at St. Jude Children's Research Hospital. The median age at presentation was 16 years (range 7-21 years). Anatomic locations included trunk and pelvis (7), upper or lower extremity (4), and head and neck (3). The median size of the lesion was 3 cm (range, 1-12 cm). Thirteen had definitive surgical resections, and one had biopsy of the mass at the time of referral. They were enrolled on ...

2000-01-15

75

Structure activity relationships to assess new chemicals under TSCA  

International Nuclear Information System (INIS)

Under Section 5 of the Toxic Substances Control Act (TSCA), manufacturers must notify the US Environmental Protection Agency (EPA) 90 days before manufacturing, processing, or importing a new chemical substance. This is referred to as a premanufacture notice (PMN). The PMN must contain certain information including chemical identity, production volume, proposed uses, estimates of exposure and release, and any health or environmental test data that are available to the submitter. Because there is no explicit statutory authority that requires testing of new chemicals prior to their entry into the market, most PMNs are submitted with little or no data. As a result, EPA has developed special techniques for hazard assessment of PMN chemicals. These include (1) evaluation of available data on the chemical itself, (2) evaluation of data on analogues of the PMN, or evaluation of data on metabolites or analogues of metabolites of the PMN, (3) use of ...

1990-06-27

76

Interconnected project 'Development and testing of a biological monitoring for effects of polycyclic aromatic hydrocarbons on man'. Final report. Verbundprojekt Entwicklung und Erprobung biologischer Ueberwachungsmethoden (Biological Monitoring) bei der Einwirkung von polycyklischen aromatischen Kohlenwasserstoffen auf den Menschen. Abschlussbericht  

Energy Technology Data Exchange (ETDEWEB)

The research project had the aim to develop a standard for measuring individual, inner stresses from polycyclic aromatic hydrocarbons (PAHs) at work. The employed method was by characterizing PAHs and metabolites of PAHs to be identified in urine with a view to developing a biological monitoring of professionally exposured persons. Using a number of PAHs relevant to work, the following questions were studied in cell culture systems and different animal-experimental models: Which metabolites are formed from the PAHs used in cell culture systems and the different animal-experimental models, and what are their ratios in percent What percentage of a PAH is excreted by experimental animals in their urine and faeces on the first, second, and third day following different forms of application What is the scale of the individual range of variation of PAH mass excretion Are these results transferable to man (orig.).

1992-01-01

77

Endogenous biosynthesis of arachidonic acid epoxides in humans: Increased formation in pregnancy-induced hypertension  

Energy Technology Data Exchange (ETDEWEB)

Arachidonic acid is metabolized by means of P450 isoenzyme(s) to form epoxyeicosatrienoic acids (EETs) and their corresponding dihydroxy derivatives (DHETs). In the present study, we established the presence in human urine of 8,9-, 11,12-, and 14,15-EETs and their corresponding DHETs by developing quantitative assays and using negative ion, chemical ionization GC/MS and octadeuterated internal standards. Urinary excretion of 8,9- and 11,12-DHET increased in healthy pregnant women compared with nonpregnant female volunteers. By contrast, excretion of 11,12-DHET and 14,15-DHET, but not the 8,9-DHET regioisomer, increased even further in patients with pregnancy-induced hypertension. Intravenous administration of (3H)14,15-EET to three dogs markedly increased its DHET in plasma. The terminal half-life ranged from 7.9-12.3 min and the volume of distribution (3.5-5.3 liters) suggested limited distribution outside the plasma compartment. Negligible radioactivity was detected in urine; this ...

1990-08-01

78

Analysis of S-adenosylmethionine and related sulfur metabolites in bacterial isolates of Pseudomonas aeruginosa (BAA-47) by liquid chromatography/electrospray ionization coupled to a hybrid linear quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometry  

British Library Electronic Table of Contents (United Kingdom)

A comprehensive and highly selective method for detecting in bacterial supernatants a modified sulfur nucleoside, S-adenosyl-L-methionine (SAM), and its metabolites, i.e., S-adenosylhomocysteine (SAH), adenosine (Ado), 5prime-deoxy-5prime-methylthioadenosine (MTA), adenine (Ade), S-adenosyl-methioninamine (dcSAM), homocysteine (Hcy) and methionine (Met), was developed. The method is based on reversed-phase liquid chromatography with positive electrospray ionization (ESI+) coupled to a hybrid linear quadrupole ion trap (LTQ) and 7-T Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A gradient elution was employed with a binary solvent of 0.05 M ammonium formate at pH 4 and acetonitrile. The assay involves a simultaneous cleanup of cell-free bacterial broths by solid-pha...

2009-01-01

79

[The metabolites of cyclic peptides from three endophytic mangrove fungi].  

Science.gov (United States)

Nine secondary metaboites of cyclic peptide were isolated from three mangrove endophytic fungi Paecilomyces sp. (treel-7), 4557,ZZF65. They were viscumamide(1),cyclo(Pro-Iso)(2),cyclo(Phe-Gly)(3),cyclo(Phe-Ana)(4),cyclo(Gly-Pro) (5),cyclo(Gly-Leu)(6), cyclo(Trp-Ana)(7),neoechinulin A(8),cyclo(Pro-Thr)(9). The compounds 1,7,8,9 were firstly isolated from marine fungus. PMID:18422185

2007-12-01

80

Two new paeciloxocins from a mangrove endophytic fungus Paecilomyces sp.  

British Library Electronic Table of Contents (United Kingdom)

Paeciloxocins A and B (2-(1-hydroxy-3-methylbutyl)- and 2-(1-acetoxy-3-methylbutyl)- 11-hydroxy-9-methyl-1-methoxy-5H,7H-dibenzo[b,g]-1,5-dioxocin-5-ones), viz., two new metabolites, were isolated from the mangrove fungus Paecilomyces sp. collected from the Taiwan Strait. Their structures were elucidated by spectral methods. Paeciloxocin A exhibited strong cytotoxicity against the hepG2 cell line.

2010-01-01

 
 
 
 
81

Product identification in industrial batch fermentation using a variable forgetting factor  

British Library Electronic Table of Contents (United Kingdom)

For reliable operation and the optimization of production, industrial fermentation processes require appropriate tools for monitoring the process in real time. This work presents the structure and operation of a soft sensor for the on-line monitoring of biomass and product concentration during salinomycin and bacitracin fermentation in an industrial, 80-m^3 batch reactor; moreover it provides a tool for evaluation of batch production verified in industrial application. The process estimation algorithm consists of decoupled growth and product models, which ensures an unbiased convergence of the estimator and the robustness of the model. The production of secondary metabolites is described with a non-structured model upgraded with a variable forgetting factor that demonstrated a successful e...

2011-01-01

82

Metabolism of benzo(a)pyrene by isolated perfused testis and testicular homogenate  

Energy Technology Data Exchange (ETDEWEB)

In an effort to improve the extrapolation of laboratory data to man and estimate risk of human reproductive toxicity associated with environmental exposure, the pharmacokinetic parameters of the testicular compartment are being studied. Of particular interest is the variety of enzyme systems capable of activating and detoxicating environmental chemicals and drugs. This report compares the metabolism of benzo(a)pyrene by the isolated perfused testis and testicular homogenates in vitro. The cell free in vitro system metabolized benzo(a)pyrene at a much greater rate than the perfused testis and produced a different spectrum of metabolites. Reliable laboratory prediction of biotransformation by the whole organ or intact animal is an essential aspect of reproductive toxicology.

1980-12-01

83

In vivo recovery of glycogen metabolism in hemolymph and tissues of a freshwater field crab Barytelphusa guerini on exposure to hexavalent chromium  

Energy Technology Data Exchange (ETDEWEB)

The in vivo toxic effects of hexavalent chromium (20 mg/liter) on hemolymph glucose, tissue glycogen, total free sugars, and active and total phosphorylases of an edible, freshwater crab Barytelphusa guerini were studied. In a 15-day exposure span followed by a 15-day postexposure recovery, the time-course alterations in these constituent segments of the glycogen metabolism indicate an inconsistent depletion in metabolite levels and elevated enzyme activities during exposure period as well as hyperglycemia. An insignificant recovery was observed in these parameters on the 15th day of the postexposure phase.

1990-08-01

84

Acute inhalation toxicity of carbonyl sulfide  

Energy Technology Data Exchange (ETDEWEB)

Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

1995-12-01

85

The relationship of urinary metabolites of carbaryl/naphthalene and chlorpyrifos with human semen quality.  

Science.gov (United States)

Most of the general population is exposed to carbaryl and other contemporary-use insecticides at low levels. Studies of laboratory animals, in addition to limited human data, show an association between carbaryl exposure and decreased semen quality. In the present study we explored whether environmental exposures to 1-naphthol (1N), a metabolite of carbaryl and naphthalene, and 3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos-methyl, are associated with decreased semen quality in humans. Subjects (n=272) were recruited through a Massachusetts infertility clinic. Individual exposures were measured as spot urinary concentrations of 1N and TCPY adjusted using specific gravity. Semen quality was assessed as sperm concentration, percent motile sperm, and percent sperm with normal morphology, along with sperm motion parameters (straight-line velocity, curvilinear velocity, and linearity). Median TCPY and 1N ...

2004-12-01

86

Measurement of 12(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid and its metabolite 12-oxo-5Z,8E,10E-heptadecatrienoic acid in human plasma by gas chromatography/negative ion chemical ionization mass spectrometry  

International Nuclear Information System (INIS)

Thromboxane A2, the predominant product of arachidonic acid metabolism in the blood platelet, is a potent vasoconstrictor and platelet agonist. During its biosynthesis from cyclic endoperoxide, 12(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) is formed in equal amounts. The further metabolism of HHT, catalyzed by 15-hydroxyprostaglandin dehydrogenase, leads to 12-oxo-5Z,8E,10E-heptadecatrienoic acid (Oxo-HT). Sample workup procedures are described which allow for the sensitive and reproducible determination of these two arachidonic acid metabolites in human plasma by gas chromatography-mass spectrometry in the presence of deuterated analogues as internal standards. HHT is derivatized to the pentafluorobenzyl ester tert-butyldimethylsilyl ether. In order to enable quantification of low concentrations of about 10 pg/ml in nonstimulated human plasma, the samples have to be purified by HPLC. Oxo-HT is derivatized to the pentafluorobenzyl ester, which is purified by ...

1990-01-01

87

Second malignancies after treatment for Ewing's sarcoma: a report of the CESS-studies  

International Nuclear Information System (INIS)

Purpose: During recent years, more intensified systemic and local treatment regimens have increased the 5-year survival figures in localized Ewing's sarcoma to more than 60%. There is, however, concern about the risk of second malignancies (SM) in long-term survivors. We have analyzed the second malignancies in patients treated in the German Ewing's Sarcoma Studies CESS 81 and CESS 86. Materials and Methods: From January 1981 through June 1991, 674 patients were registered in the two sequential multicentric Ewing's sarcoma trials CESS 81 (recruitment period 1981-1985) and CESS 86 (1986-1991). The systemic treatment in both studies consisted of a four-drug-regimen (VACA = vincristine, actinomycin D, cyclophosphamide, and adriamycin; or VAIA = vincristine, actinomycin D, ifosfamide, and adriamycin) and a total number of four courses, each lasting nine weeks, was recommended by the protocol. Local therapy in curative patients was either complete surgery (n = 162), ...

1998-09-01

88

[Destruction of radioactive particles by strains of Cladosporium cladosporoides (FRES.) de Vries].  

Science.gov (United States)

Reactions on the ionizing radiation of 14 Cladosporium cladosporioides strains were studied. Only 5 of them displayed radiotropizm. The ability of C. cladosporioides strains 4 and 5 with positive radiotropizm and museum C. cladosporioides strain 396 and its alb-mutant SM without positive radiotropizm to destruct radioactive particles of Chernobyl and explosion origin was studied. Two ways of radioactive particles destruction by C. cladosporioides were established, one of them is a direct way by fungal overgrowth of hot particles and the second one an indirect way only by fungal metabolites. Mycelium of the studied C. cladosporioides strains sorbed radionuclides from radioactive particles during cultivation on the liquid and agarized media. No certain inclinations of the individual strains to accumulation of radionuclides 137Cs or 152Eu were ascertained. PMID:12664550

89

UV inactivation: Combined effects of UV radiation and xenobiotics in two strains of Saccharomyces  

International Nuclear Information System (INIS)

The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae - a wild type strain and a mutant deficient in excision repair - were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation in Saccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains. (orig.).

90

The disruption of l-carnitine metabolism by aluminum toxicity and oxidative stress promotes dyslipidemia in human astrocytic and hepatic cells  

British Library Electronic Table of Contents (United Kingdom)

l-Carnitine is a critical metabolite indispensable for the metabolism of lipids as it facilitates fatty acid transport into the mitochondrion where b-oxidation occurs. Human astrocytes (CCF-STTG1 cells) and hepatocytes (HepG2 cells) exposed to aluminum (Al) and hydrogen peroxide (H2O2), were characterized with lower levels of l-carnitine, diminished b-oxidation, and increased lipid accumulation compared to the controls. g-Butyrobetainealdehyde dehydrogenase (BADH) and butyrobetaine dioxygenase (BBDOX), two key enzymes mediating the biogenesis of l-carnitine, were sharply reduced during Al and H2O2 challenge. Exposure of the Al and H2O2-treated cells to a-ketoglutarate (KG), led to the recovery of l-carnitine production with the concomitant reduction in ROS levels. It appears that the chann...

2011-01-01

91

Tertiary-Butanol: A toxicological review  

British Library Electronic Table of Contents (United Kingdom)

Tert-Butanol is an important intermediate in industrial chemical synthesis, particularly of fuel oxygenates. Human exposure to tert-butanol may occur following fuel oxygenate metabolism or biodegradation. It is poorly absorbed through skin, but is rapidly absorbed upon inhalation or ingestion and distributed to tissues throughout the body. Elimination from blood is slower and the half-life increases with dose. It is largely metabolised by oxidation via 2-methyl-1,2-propanediol to 2-hydroxyisobutyrate, the dominant urinary metabolites. Conjugations also occur and acetone may be found in urine at high doses. The single-dose systemic toxicity of tert-butanol is low, but it is irritant to skin and eyes; high oral doses produce ataxia and hypoactivity and repeated exposure can induce dependence...

2010-01-01

92

Root exudation of sugars, amino acids, and organic acids by maize as affected by nitrogen, phosphorus, potassium, and iron deficiency  

British Library Electronic Table of Contents (United Kingdom)

Abstract Root exudates play a major role in the mobilization of sparingly soluble nutrients in the rhizosphere. Since the amount and composition of major metabolites in root exudates from one plant species have not yet been systematically compared under different nutrient deficiencies, relations between exudation patterns and the type of nutrient being deficient remain poorly understood. Comparing root exudates from axenically grown maize plants exposed to N, K, P, or Fe deficiency showed a higher release of glutamate, glucose, ribitol, and citrate from Fe-deficient plants, while P deficiency stimulated the release of -aminobutyric acid and carbohydrates. Potassium-starved plants released less sugars, in particular glycerol, ribitol, fructose, and maltose, while under N deficiency lower am...

2011-01-01

93

Persistent halogenated compounds in two typical marine aquaculture zones of South China  

British Library Electronic Table of Contents (United Kingdom)

Samples of two seawater farmed fish (crimson snapper (Lutjanus erythopterus) and snubnose pompano (Trachinotus blochii)), water, air, sediment, fish feed, macroalgae and phytoplankton were collected from two estuarine bays (Daya Bay and Hailing Bay) in South China. The concentrations of persistent halogenated compounds (PHCs) including polybrominated diphenyl ethers (PBDEs), organochlorine pesticides and polychlorinated biphenyls (PCBs) varied widely with the different sample matrices under investigation. The compositional patterns in fish, fish feed, macroalgae and phytoplankton, as well as the good correlations between the abundances of p,pprime-DDT and BDE-209 and their metabolites (i.e., p,pprime-DDD and p,pprime-DDE for p,pprime-DDT and BDE-47 for BDE-209) in fish indicated the occurr...

2011-01-01

94

Nutrition and Physical Activity in Aging, Obesity, and Cancer  

British Library Electronic Table of Contents (United Kingdom)

A wide variety of phytochemicals present in our diet, including fruits, vegetables, and spices, have been shown to possess a broad range of health-beneficial properties. The cytoprotective and restorative effects of dietary phytochemicals are likely to result from the modulation of several distinct cellular signal transduction pathways. Many dietary phytochemicals that are synthesized as secondary metabolites function as toxins, that is, -phytoalexins,- and hence protect plants against insects and other damaging organisms and stresses. However, at the relatively low doses consumed by humans and other mammals, these same toxic plant-derived chemicals, as mild stressors, activate adaptive cellular response signaling, conferring stress resistance and other health benefits. This phenomenon has...

2011-01-01

95

Neurochemical deficits in the cerebellar vermis in child offspring of parents with bipolar disorder  

British Library Electronic Table of Contents (United Kingdom)

Singh MK, Spielman D, Libby A, Adams E, Acquaye T, Howe M, Kelley R, Reiss A, Chang KD. Neurochemical deficits in the cerebellar vermis in child offspring of parents with bipolar disorder.-Bipolar Disord 2011: 13: 189-197. 2011 The Authors.-Journal compilation 2011 John Wiley & Sons A/S. Objectives:- We aimed to compare concentrations of N-acetyl aspartate, myo-inositol, and other neurometabolites in the cerebellar vermis of offspring at risk for bipolar disorder (BD) and healthy controls to examine whether changes in these neuronal metabolite concentrations occur in at-risk offspring prior to the onset of mania. Methods:- A total of 22 children and adolescents aged 9-17-years with a familial risk for bipolar I or II disorder [at-risk offspring with non-bipolar I disorder mood symptoms (AR...

2011-01-01

96

Near infrared spectroscopy-derived interstitial hydrogen ion concentration and tissue oxygen saturation during ambulation  

British Library Electronic Table of Contents (United Kingdom)

The objective of this study was to determine whether walking and running at different treadmill speeds resulted in different metabolic and cardiovascular responses in the vastus lateralis (VL) and lateral gastrocnemius (LG) by examining metabolite accumulation and tissue oxygen saturation. Ten healthy subjects (6 males, 4 females) completed a submaximal treadmill exercise test, beginning at 3.2?km?h?1 and increasing by 1.6?km?h?1 increments every 3?min until reaching 85% of age-predicted maximal heart rate. Muscle tissue oxygenation (SO2), total hemoglobin (HbT) and interstitial hydrogen ion concentration ([H+]) were calculated from near infrared spectra collected from VL and LG. The [H+] threshold for each muscle was determined using a simultaneous bilinear regression. Muscle and treadmil...

2011-01-01

97

Myocardial pharmacokinetics of ebastine, a substrate for cytochrome P450 2J, in rat isolated heart  

British Library Electronic Table of Contents (United Kingdom)

BACKGROUND AND PURPOSE It is well established that cytochrome P450 2J (CYP2J) enzymes are expressed preferentially in the heart, and that ebastine is a substrate for CYP2J, but it is not known whether ebastine is metabolized in myocardium. Therefore, we investigated its pharmacokinetics in the rat isolated perfused heart. EXPERIMENTAL APPROACH Rat isolated hearts were perfused in the recirculating mode with ebastine for 130-min. The concentrations of ebastine and its metabolites, hydroxyebastine and carebastine, were measured using liquid chromatography with a tandem mass spectrometry. The data were analysed by a compartmental model. The time course of negative inotropic response was linked to ebastine concentration to determine the concentration-effect relationship. KEY RESULTS Ebastine w...

2011-01-01

98

Localized H-1 MR spectroscopy in postnatal brain development  

International Nuclear Information System (INIS)

This paper investigates regional and age-related changes in metabolite ratios using image-localized H-1 MR spectroscopy in children. Twenty-seven children referred for MR imaging of the brain underwent localized H-1 MR spectroscopy with a Siemens 1.5-T whole-body imager. Localization to 2 x 2 x 2-cm volumes of interest was achieved with a stimulated-echo or spin-echo technique. Repetition times of 1,600 and 5,000 msec were used, with echo times varying between 68 and 270 msec. Total combined imaging and spectroscopy times were 90-120 minutes.

1990-11-25

99

Levels and regional trends of persistent organochlorines and polybrominated diphenyl ethers in Asian breast milk demonstrate POPs signatures unique to individual countries  

British Library Electronic Table of Contents (United Kingdom)

Human breast milk samples collected in 2007?2008 from four countries, Vietnam (Hanoi), China (Beijing), Korea (Seoul) and Japan (Sendai, Kyoto and Takayama), were analyzed for persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane-related compounds (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Comparing with previous surveys, the present study indicates that the DDTs in breast milk from China and Vietnam had gradually decreased during the last decade, but were still 5?10 times higher than those in other nations. The ratios of p,p?-DDE/p,p?-DDT and o,p?-DDT/p,p?-DDT were higher in Beijing than in the other countries, suggesting that there...

2009-01-01

100

Inhibition of Metabolism of Diethylene Glycol Prevents Target Organ Toxicity in Rats  

British Library Electronic Table of Contents (United Kingdom)

Diethylene glycol (DEG) is an industrial chemical, the misuse of which has led to numerous epidemic poisonings worldwide. The mechanism of its toxicity has not been defined as to the precise relationship between the metabolism of DEG and target organ toxicity. The purpose of this study was to investigate the mechanism for the acute toxicity of DEG, and the effect of the alcohol dehydrogenase inhibitor 4-methylpyrazole (fomepizole), by determining the relationship between accumulation of DEG or its metabolites and the resulting kidney and liver toxicity. Rats were treated by oral gavage with water, 2 g/kg DEG (low dose), 10 g/kg DEG (high dose), or 10 g/kg DEG + fomepizole, and blood and urine were collected over 48 h. Rats treated with high-dose DEG had metabolic acidosis, increased BUN an...

2010-01-01

 
 
 
 
101

High-Throughput Screening of Drugs of Abuse in Urine by Supported Liquid?Liquid Extraction and UHPLC Coupled to Tandem MS  

British Library Electronic Table of Contents (United Kingdom)

A qualitative method, involving supported liquid?liquid extraction (SLE) and ultra high pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS?MS), was developed for the rapid tentative identification of various drugs of abuse in urine. In this study, 28 drugs and metabolites were covered by the screening procedure. Before analysis, urine samples were extracted by SLE and good extraction recoveries were obtained for most investigated compounds. The UHPLC strategy was then selected for the rapid separation of amphetamines, cocaine, opiates and related compounds in urine. Using columns packed with sub-2??m particles, analysis time was reduced down to 2?min, while maintaining acceptable performance. Finally, the detection was by tandem MS operating in the single reaction...

2009-01-01

102

Genetic Variation of Lodgepole Pine, Pinus contorta var. latifolia, Chemical and Physical Defenses that Affect Mountain Pine Beetle, Dendroctonus ponderosae, Attack and Tree Mortality  

British Library Electronic Table of Contents (United Kingdom)

Plant secondary chemistry is determined by both genetic and environmental factors, and while large intraspecific variation in secondary chemistry has been reported frequently, the levels of genetic variation of many secondary metabolites in forest trees in the context of potential resistance against pests have been rarely investigated. We examined the effect of tree genotype and environment/site on the variation in defensive secondary chemistry of lodgepole pine, Pinus contorta var. latifolia, against the fungus, Grosmannia clavigera (formerly known as Ophiostoma clavigerum), associated with the mountain pine beetle, Dendroctonus ponderosae. Terpenoids were analyzed in phloem samples from 887, 20-yr-old trees originating from 45 half-sibling families planted at two sites. Samples were coll...

2011-01-01

103

Fluorocarbons and cardiac arrhythmia: does difluorodichloromethane (FC 12) inhibit cardiac metabolism  

Energy Technology Data Exchange (ETDEWEB)

Certain fluorocarbons, such as difluorodichloromethane (FC 12), depress the cardiovascular system by diminution of all the transmembrane ionic conductances in cardiac tissues. Does FC 12 also inhibit active transport and thus enzymatic activity and cellular energy. We measured phosphocreatine (PC), adenosine triphosphate (ATP) and cyclic adenosine monophosphate (AMPc) in rat hearts. Rats were randomly divided into 4 groups; 2 control groups: one breathing a mixture of oxygen (21%) and nitrogen (79%) (group C) and the other breathing the same mixture but simultaneously perfused with 1 microgram/kg/min. epinephrine (groupe E-C); 2 trial groups T and E-T where nitrogen was replaced by FC 12. The maximal FC 12 concentration of 720 micrograms/ml in arterial blood produced no significant difference in the concentrations of these three metabolites compared with controls.

1986-01-01

104

Five naturally bioactive molecules including two rhamnopyranoside derivatives isolated from the Streptomyces sp. strain TN58  

British Library Electronic Table of Contents (United Kingdom)

Extraction of 25 L fermentation broth of the newly isolated Streptomyces sp. strain TN58 and various separation and purification steps led to the isolation of five bioactive metabolites, namely brevianamide F (C1), reported from a streptomycete for the first time, N?-acetyltryptamine (C2), thiazolidomycin (C3), and two rhamnopyranosides (C4 and C5). These two rhamnopyranosides were produced directly, without precursor addition. The chemical structure of these five active compounds was established on the basis of 1H, 13C/APT and 2D NMR spectra, ESI and EI-MS data, and by comparison with data from the literature. According to the biological studies, we show in this work that the compounds C1, C2, C4 and C5 possess antimicrobial activities.

2009-01-01

105

Endophytic fungus Trichothecium roseum LZ93 antagonizing pathogenic fungi in vitro and its secondary metabolites  

British Library Electronic Table of Contents (United Kingdom)

The endophytic fungus Trichothecium roseum LZ93 from Maytenus hookeri was found to antagonize other pathogenic fungi in vitro. To identify which compound contributed substantially to the antagonism, we fermented the strain and purified its fermentation products. Eleven compounds were obtained, including two trichothecenes, five rosenonolactones, two cardiotonic cyclodepsipeptides, and two sterols. Compound 11?-hydroxyrosenonolactone (1) was assigned according to 1D and 2D-NMR data for the first time. At the same time, the 1H and 13C-NMR assignments for 6?-hydroxyrosenonolactone (2) were revised. Of all of them, only trichothecin (6) showed strong antifungal activity. Based on our observations of the antagonistic activity and the other experimental results, we suggest that the antifungal co...

2010-01-01

106

Effects of fungicides on endophytic fungi and photosynthesis in seedlings of a tropical tree, guarea guidonia (meliaceae)  

International Nuclear Information System (INIS)

Endophytes are microorganisms that live within healthy plant tissues, and include fungi and bacteria. They can be mutualists, comensals or even latent pathogens. Presence of these endosymbionts may affect host physiology, for example by consuming products of photosynthesis (endophytes are heterotrophs) or producing toxic metabolites. In this work two fungicides were used to eliminate fungal endophytes from seedlings of guarea guidonia. light saturated photosynthesis (Amax) was measured in endophytefree plants and compared with control plants. Each fungicide killed different fungal endosymbionts. phomopsis was more susceptible to benomyl while colletotrichum was more susceptible to propiconazole. Although suggestive, values of Amax were not significantly different for each treatment compared with control plants. No prediction can be made at this point about the final outcome of a given plantendophytic fungi interaction

2005-12-01

107

Differential expression of farnesyl diphosphate synthase gene from Withania somnifera in different chemotypes and in response to elicitors  

British Library Electronic Table of Contents (United Kingdom)

Withania somnifera (L.) Dunal (Family, Solanaceae), commonly known as Ashwagandha is one of the most valuable medicinal plants synthesizing large number of pharmacologically active secondary metabolites known as withanolides. Though the plant has been well characterized in terms of phytochemical profiles as well as pharmaceutical activities, not much is known about the genes responsible for biosynthesis of these compounds. In this study, we have characterized a gene encoding farnesyl diphosphate synthase (FPPS; EC 2.5.1.10), a key enzyme in the pathway of biosynthesis of isoprenoids, from W. somnifera. The full-length cDNA of Withania somnifera FPPS (WsFPPS) of 1,253?bps encodes a polypeptide of 343 amino acids. The amino acid sequence homology and phylogenetic analysis suggest that WsFPPS...

2011-01-01

108

Comparative Evaluation of Different Cell Lysis and Extraction Methods for Studying Benzo(a)pyrene Metabolism in HT-29 Colon Cancer Cell Cultures  

British Library Electronic Table of Contents (United Kingdom)

Abstract Lysis and extraction of cells are essential sample processing steps for investigations pertaining to metabolism of xenobiotics in cell culture studies. Of particular importance to these procedures are maintaining high lysis efficiency and analyte integrity as they influence the qualitative and quantitative distribution of drug and toxicant metabolites in the intra- and extracellular milieus. In this study we have compared the efficiency of different procedures viz. homogenization, sonication, bead beating, and molecular grinding resin treatment for disruption of HT-29 colon cells exposed to benzo(a)pyrene (BaP), a polycyclic aromatic hydrocarbon (PAH) compound and a suspected colon carcinogen. Also, we have evaluated the efficiency of various procedures for extracting BaP parent c...

2011-01-01

109

Coalification by clay-catalyzed oligomerization of plant monomers. [Methyleugenol  

Science.gov (United States)

During this report period, we have obtained a model of montmorillonite clay, and this model has been of great assistance in visualizing how the chemistry of substrate molecules might be altered as it occurs on the surface of the clay. A stereochemical representation of this montmorillonite model is shown. Of particular significance, this model indicates that hydroxyl groups are located in the center of each siloxane ring on the surface of the montmorillonite clay. These hydroxyl groups might serve to bond substrate molecules to the surface of the clay. The next step in our systematic examination of the radical cation-initiated dimerization of plant monomers from the C{sub 6}-C{sub 3} pool of shikimic acid metabolites was to study the dimerization of cinnamic acid and its derivatives. In the next block of research, we examined the reaction of montmorillonite clay (K-10) with methyleugenol. 2 refs.

1990-01-01

110

An overview of field-specific designs of microbial EOR  

Energy Technology Data Exchange (ETDEWEB)

The selection and design of an MEOR process for application in a specific field involves geological, reservoir, and biological characterization. Microbially mediated oil recovery mechanisms (bigenic gas, biopolymers, and biosurfactants) are defined by the types of microorganisms used. The engineering and biological character of a given reservoir must be understood to correctly select a microbial system to enhance oil recovery. This paper discusses the methods used to evaluate three fields with distinct characteristics and production problems for the applicability of MEOR would not be applicable in two of the three fields considered. The development of a microbial oil recovery process for the third field appeared promising. Development of a bacterial consortium capable of producing the desired metabolites was initiated, and field isolates were characterized.

1995-12-31

111

Abscisic Acid in Soil Facilitates Community Succession in Three Forests in China  

British Library Electronic Table of Contents (United Kingdom)

Plants release secondary metabolites into the soil that change the chemical environment around them. Exogenous abscisic acid (ABA) is an important allelochemical whose role in successional trajectories has not been examined. We hypothesized that ABA can accumulate in the soil through successional processes and have an influence on forest dynamics. To this end, we investigated the distribution of ABA in forest communities from early to late successional stages and the response of dominant species to the gradient of ABA concentrations in three types of forests from northern to southern China. Concentrations of ABA in the soils of three forest types increased from early to late successional stages. Pioneer species? litters had the lowest ABA content, and their seed germination and seedling ea...

2011-01-01

112

A comparison of hepatic in vitro metabolism of T-2 toxin in rats, pigs, chickens, and carp  

British Library Electronic Table of Contents (United Kingdom)

T-2 toxin, a highly toxic member of the type-A trichothecenes, is produced by various Fusarium moulds that can potentially affect human health. It is strongly cytotoxic for human hematopoietic progenitors. Alimentary toxic aleukia (ATA), a disease typically associated with human, is primarily induced by T-2 toxin. A comparison of the metabolism of T-2 toxin incubated with hepatocytes of rats, piglets, chickens, and the hepatic subcellular fractions (microsomes and cytosol) of piglets, chickens, rats, and carp (common carp and grass carp) was carried out. The activities of the recombinant pig CYP3A29 on the transformation of T-2 and HT-2 toxins were preliminary studied. Metabolites were identified by novel LC/MS-IT-TOF. Qualitative similarities and differences across the species were observ...

2011-01-01

113

Propanil-induced methemoglobinemia and hemoglobin binding in the rat  

International Nuclear Information System (INIS)

Administration of [ring-U-14C]propanil (3,4-dichloropropionanilide) to male Sprague-Dawley rats (30, 100, and 300 mg/kg, ip) increased the formation of methemoglobin at the two highest doses. Following a propanil dose of 100 mg/kg, methemoglobin formation attained a maximum level of 5% by 1.5 hr and declined to normal levels (approximately 2.5%) by 12 hr. Hemoglobin binding attained a maximum level of 50 pmol/mg protein by 12 hr, and remained constant for 24 hr. Following a propanil dose of 300 mg/kg, methemoglobin formation attained a maximum level of 24% by 4.5 hr, and declined to a level of 5% by 24 hr. Hemoglobin binding attained a maximum level of 425 pmol/mg protein by 12 hr, and remained constant for 24 hr. Hemoglobin binding was also detected at the lowest propanil dose (10 pmol/mg protein) even though methemoglobin formation was not observed. HPLC analysis of alkaline-treated hemoglobin from propanil-treated rats indicated the presence of one radiolabeled compound with the ...

114

Use of nuclear techniques in studies of uptake and metabolic fate of xenobiotics in plants  

International Nuclear Information System (INIS)

The use of municipal sewage sludge as a fertilizer in agriculture is a convenient method of disposal. However, sludge is often contaminated with toxic organic compounds such as dioxins, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs), with implications for soil fertility and quality of crops for human and animal consumption. These compounds can be assimilated by intact plants or in-vitro cell-Culture systems. The amount of uptake depends on the plant species and on the physico-chemical conditions that influence, for example, molecular configuration; uptake rates are higher with low-molecular-weight and polar compounds. The xenobiotic can be converted to polar conjugates and hydroxylated metabolites that may also be toxic. In some cases, large amounts of the compound and/or its metabolic products are incorporated into non-extractable residues. The bound residues, especially those associated with carbohydrate fractions of the cell wall, ...

1997-10-01

115

Toxic chemicals, including aromatic and chlorinated hydrocarbons and their derivatives, and liver lesions in white croaker (Genyonemus lineatus) from the vicinity of Los Angeles  

Energy Technology Data Exchange (ETDEWEB)

High concentrations of toxic chemicals in sediment and white croaker (Genyonemus lineatus), as well as liver diseases (e.g., carcinomas) in this species, were found in the Los Angeles area. The highest concentrations of aromatic hydrocarbons (AHs) in the sediment were in San Pedro Bay, and the highest concentrations of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) derivatives were in sediment from near the White Point sewer outfall. Concentrations of AHs, polychlorobiphenyls (PCBs), and DDT derivatives were generally higher in food organisms from the croaker's stomach than in sediment. Moreover, croaker from San Pedro Bay and White Point were substantially contaminated with DDT derivatives and metabolites of aromatic compounds, compared to croaker from the Hyperion outfall and Dana Point. The evidence suggest that the observed pathological conditions of the liver were associated with exposure of the croaker to toxic chemicals, which occurred, at ...

1987-08-01

116

Radiosynthesis of hydrogel confined to hollow-fiber membranes for the design of a bioartificial extra-corporeal liver  

Energy Technology Data Exchange (ETDEWEB)

Current bioartificial extra-corporeal systems are bioreactors where cells are separated from the surrounding media by porous polymeric membranes. The present work focuses on the design of membranes that allow the differential diffusion of plasma metabolites and proteins such as immunoglobulin (IgG). This design will improve catabolites removal and reduce possible immune response and virus infection. We demonstrate the feasibility to synthesize the hydrogels confined to the macroporous structure of membranes by radiation-induced in situ polymerization. The hollow-fiber membranes were soaked in aqueous monomeric solution, rinsed and irradiated while submerged in oil. This procedure confined the hydrogel to the void internal volume of the pores of the membrane. Hydrogels of polyacrylamide and polyHEMA were synthesized this way by irradiation at 10 kGy. Hydraulic permeability and diffusion of glucose, albumin and IgG were measured in these hydrogel-filled membranes. ...

2007-08-15

117

Persistence of terbufos and its metabolites in soil and maize  

International Nuclear Information System (INIS)

Degradation of "1"4C terbufos was studied under greenhouse conditions. A mixture of "1"4C labelled compound (2.48 x 10"4 Bq of O-ethyl-1- "1"4C) und unlabelled compound (0.09 g of the granule formulation Counter 10 G) was applied to pots containing 750 g of sandy loam clay Ultisol soil with 4.9% organic matter and a cation exchange capacity of 7.6. Two treatments were established, one where maize (cultivar Cristiani) was grown and the other without plants. The soil and plants were extracted at 0, 4, 8, 16, 32 and 64 days and analyzed by a liquid scintillation counter, gas chromatography-flame photometric detector (GC-FPD) and autoradiography. The total "1"4C compounds extracted on day 64 were 31 #+-# 5.6% of the radioactivity applied in the treatments with plants and 46.1 #+-# 1.1% without plants. From the autoradiography results it can be concluded that all times the compounds identified by this technique were terbufos, terbufos sulphoxide and terbufos sulphone. These results will be ...

1996-07-01

118

New Lactone and Xanthone Derivatives Produced by a Mangrove Endophytic Fungus Phoma sp. SK3RW1M from the South China Sea  

British Library Electronic Table of Contents (United Kingdom)

A new lactone, 1,8-dihydroxy-10-methoxy-3-methyldibenzo[b,e]oxepine-6,11-dione (1), and two new xanthones, 1-hydroxy-8-(hydroxymethyl)-6-methoxy-3-methyl-9H-xanthen-9-one (2) and 1-hydroxy-8-(hydroxymethyl)-3-methoxy-6-methyl-9H-xanthen-9-one (3), were isolated from a mangrove endophytic fungus Phoma sp. SK3RW1M collected from the South China Sea. This is the first report on xanthone derivatives isolated as secondary metabolites from Phoma species. Their structures were elucidated by spectroscopic methods, mainly 1D- and 2D-NMR techniques, and the structure of compound 2 was confirmed by X-ray crystallography. Cytotoxicity assays showed that compounds 1-3 were inactive against KB and KBv200 cells.

2010-01-01

119

Increasing the pore size of electrospun scaffolds.  

Science.gov (United States)

Electrospinning has gained much attention in the past decade as an effective means of generating nano- to micro-scale polymer fibers that resemble native extracellular matrix. High porosity, pore interconnectivity, and large surface area to volume ratio of electrospun scaffolds make them highly conducive to cellular adhesion and growth. However, inherently small pores of electrospun scaffolds do not promote adequate cellular infiltration and tissue ingrowth. Cellular infiltration into the scaffold is essential for a range of tissue engineering applications and is particularly important in skin and musculoskeletal engineering. Pore size, porosity, and pore interconnectivity dictate the extent of cellular infiltration and tissue ingrowth into the scaffold; influence a range of cellular processes; and are crucial for diffusion of nutrients, metabolites, and waste products. A number of electrospinning techniques and postelectrospinning modifications have, therefore, ...

2011-08-04

120

Genetic engineering of group 2 sigma factor SigE widely activates expressions of sugar catabolic genes in Synechocystis species PCC 6803.  

Science.gov (United States)

Metabolic engineering of photosynthetic organisms is required for utilization of light energy and for reducing carbon emissions.Control of transcriptional regulators is a powerful approach for changing cellular dynamics, because a set of genes is concomitantly regulated. Here, we show that overexpression of a group 2 ? factor, SigE, enhances the expressions of sugar catabolic genes in the unicellular cyanobacterium, Synechocystis sp. PCC 6803. Transcriptome analysis revealed that genes for the oxidative pentose phosphate pathway and glycogen catabolism are induced by overproduction of SigE. Immunoblotting showed that protein levels of sugar catabolic enzymes, such as glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glycogen phosphorylase, and isoamylase, are increased. Glycogen levels are reduced in the SigE-overexpressing strain grown under light. Metabolome analysis revealed that metabolite levels of the TCA cycle and acetyl-CoA are ...

2011-07-11

 
 
 
 
121

Enzymatic mechanism in low chloride media: influence of glucose oxidase on the electrochemical behaviour of AISI 316L stainless steel; Mecanisme enzymatique en milieux faiblement chlorures: influence de la glucose oxydase sur le comportement electrochimique de l'acier inoxydable AISI 316L  

Energy Technology Data Exchange (ETDEWEB)

The open circuit potential (OCP) of stainless steels immersed in natural waters generally increases with time. This phenomenon is strongly linked to the formation of a bio-film on the surface. Several studies have proved that the bio-film modifies the reaction of reduction of dissolved oxygen and that it acts mainly on the cathodic processes. One of the hypotheses explaining the action of the bio-film involves certain bacteria which use dissolved oxygen and extracellular enzymes to produce reactive oxygen species. Among this kind of metabolites is hydrogen peroxide H{sub 2}O{sub 2}. This compound interacts with the passive layer of stainless steels and affects their electrochemical behaviour, even when the chloride concentration is low. The aim of this work is to study the influence of an enzymatic reaction (of the oxidoreductase type) on anodic and cathodic processes on AISI 316L stainless steel. Experiments are carried out in two artificial electrolytes ...

2006-07-01

122

Effect of pentachlorophenol on the activation of 2,6-dinitrotoluene to genotoxic urinary metabolites in CD-1 mice: A comparison of G1 enzyme activities and urine mutagenicity  

Energy Technology Data Exchange (ETDEWEB)

2,6-Dinitrotoluene (2,6-DNT) and pentachlorophenol (PCP) are used for industrial purposes and are found in the environment as hazardous contaminants. Because concurrent exposure to both compounds can occur, it is of interest to determine if organochlorine compounds potentiate the effect of nitroaromatic chemicals. A significant increase in mutagenicity was observed in urines from mice treated with 2,6-DNT alone and in combination with PCP. By week 4, mice that received both 2,6-DNT and PCP excreted urine that was more mutagenic than that from animals which received only 2,6-DNT. At weeks 2 and 4, mice were sacrificed and intestinal enzyme activities (nitroreductase, azo reductase, {beta}-glucuronidase, dechlorinase, and dehydrochlorinase) were quantitated. The enhanced genotoxicity observed in urines from 2,6-DNT/PCP-treated mice coincided with a decrease in nitroreductase and an increase in {beta}-glucuronidase activities in the small intestine.

1991-01-01

123

Effect of butylated hydroxytoluene pretreatment on the excretion, tissue distribution and DNA binding of (/sup 14/C)aflatoxin B1 in the rat  

Energy Technology Data Exchange (ETDEWEB)

The effect of butylated hydroxytoluene (BHT) pretreatment (0.5% in the diet for 10 days) on the excretion, tissue distribution and DNA binding of orally administered (/sup 14/C)aflatoxin B1 (AFB1) was determined in male Fischer F344 rats. The amount of radioactivity excreted in the urine and feces by 24 hr was higher in BHT-treated rats than in controls. Treatment with BHT enhanced the excretion of water-soluble metabolites in the urine and in the large intestines plus feces at the earlier sampling times. The amount of radioactivity bound to hepatic nuclear DNA was six times less in the BHT-pretreated rats than in controls 6 hr after administration of the isotope. The half-lives of (/sup 14/C)DNA in the rat liver were 30 and 46 hr for control and BHT-pretreated rats, respectively. These results indicate that BHT pretreatment may protect the animal from the carcinogenic effects of AFB1 by enhancing the detoxification and excretion of the mycotoxin.

1985-06-01

124

Data Merging for Integrated Microarray and Proteomic Analysis  

Energy Technology Data Exchange (ETDEWEB)

The functioning of even a simple system is much more complicated than the sum of its genes, proteins and metabolites. A premise of systems biology is that molecular profiling will lead to the discovery and characterization of important disease pathways. However, as multiple levels of effector pathway regulation appear to be the norm rather than the exception, a significant challenge presented by high-throughput genomics and proteomics technologies is to extract the biological implications of complex data. Thus, integration of heterogeneous types of data generated from diverse global technology platforms represents the first challenge in developing the necessary foundational databases needed for predictive modeling of cell and tissue responses. Given the apparent difficulty in defining the correspondence between gene expression and protein abundance measured in several systems to date, how do we make sense of these data and design the next experiment? In this ...

2006-05-10

125

Chemometric source identification of PCDD/Fs and other POPs in sediment cores of North-East Germany  

Energy Technology Data Exchange (ETDEWEB)

A broad range of persistent organic pollutants (POPs) and selected heavy metals has been analysed in sediment cores of North-East Germany. The pollutants analysed include polychlorinated dioxins and furans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), several pesticides (DDT, HCH, CBz) and its metabolites as well as selected heavy metals. The sediment cores were sampled at five locations, reflecting a range of anthropogenic influences and background contamination: Arkona Basin (AK) representing a remote marine site, Lake Bugsin (BS) a background location only with atmospheric deposition, Lake Quenz (QS) close to the industrial city of Brandenburg, Teltowkanal (TK) in the suburban-industrial zone of Berlin and Lake White (WS) in the centre of Berlin. The age of the lower part of the AK, BS and TK cores were dated at 100-150 years. Results of selected pollutants (PCDD/Fs) have been presented earlier, focussing on the depth ...

2004-09-15

126

6-Methyl-1,2,4-benzenetriol, a new intermediate in penicillic acid biosynthesis in Penicillium cyclopium  

International Nuclear Information System (INIS)

Penicillic acid-negative mutants were obtained from a color mutant derived from Penicillium cyclopium NRRL 1888 through N-methyl-N'-nitro-N-nitrosoguanidine treatment. One mutant (SK2N6) accumulated 6-methyl-1,2,4-benzenetriol, which was not previously known to be a metabolite of P. cyclopium, in addition to orsellinic acid and orcinol. The radioactivity of [1-"1"4C]acetic acid was rapidly incorporated into 6-methyl-1,2,4-benzenetriol in a culture of P. cyclopium SK2N6. Moreover, the radioactivity of ["1"4C]6-methyl-1,2,4-benzenetriol was efficiently incorporated into penicillic acid in a culture of P. cyclopium NRRL 1888. These data indicate that 6-methyl-1,2,4-benzenetriol is a precursor for penicillic acid biosynthesis. The results on the addition of 1,4-dihydroxy-6-methoxy-2-methylbenzene, 6-methoxy-2-methylbenzoquinone (1,4), and 1-O-methylorcinol to a culture of P. cyclopium SK2N6 indicated that only the former two compounds are converted to penicillic acid. ...

127

beta. -Endorphin and related peptides suppress phorbol myristate acetate-induced respiratory burst in human polymorphonuclear leukocytes  

Energy Technology Data Exchange (ETDEWEB)

In the present study, the immunomodulatory effect of {beta}-endorphin ({beta}-E) and shorter pro-opiomelancortin (POMC) fragments was evaluated by assessing their influence on respiratory burst in human polymorphonuclear leukocytes (PMN). The effect of the peptides on phorbol myristate acetate (PMA)-stimulated production of reactive oxygen metabolites was measured in a lucigenin-enhanced chemiluminescence (CL) assay. Both POMC peptides with opiate-like activity and their non-opioid derivatives were tested. With the exception of {alpha}-E, PMA-stimulated respiratory burst was suppressed by all POMC fragments tested. A U-shaped dose-response relation was observed. Doses lower than 10{sup {minus}17}M and higher than 10{sup {minus}8}M were without effect. {beta}-E and dT{beta}E both suppressed PMA-induced oxidative burst in human PMN at physiological concentrations. {gamma}-E and dT{gamma}E proved to be less potent inhibitors, reaching maximal effect at higher ...

1989-01-01

128

Toxicity of ultraviolet-irradiated halothane in mice  

Energy Technology Data Exchange (ETDEWEB)

One such agent is the widely used anesthetic, halothane. To study the toxicity of u.v. decomposed halothane, mice were exposed to anesthetic concentrations (1.3%) of non- and u.v.-irradiated halothane in oxygen for 90 min. Halothane sleeping times increased from 14.3 min to 72.5 min. Microsomal mixed function oxidase activity decreased, as shown by prolonged pentobarbital sleeping times 1 day after exposure to halothane and irradiated halothane (54.6 min and 149.1 min, respectively, as compared to a 34.6-min control). Quantitative and qualitative differences were found in the amount of (/sup 14/C)-pentobarbital metabolites excreted by u.v. irradiated halothane-exposed mice compared to either oxygen or non-irradiated halothane-exposed groups. In addition, serum glutamic-oxalacetic transaminase (SGOT) of irradiated halothane-exposed mice increased to 233% of the control values, and serum glutamic-pyruvic transaminase (SGPT) were 377% of control values. No significant ...

1982-01-01

129

The use of short-echo-time {sup 1}H MRS for childhood cerebellar tumours prior to histopathological diagnosis  

Energy Technology Data Exchange (ETDEWEB)

Proton magnetic resonance spectroscopy (MRS) measures concentrations of metabolites in vivo and provides a powerful method for identifying tumours. MRS has not entered routine clinical use partly due to the difficulty of analysing the spectra. To create a straightforward method for interpreting short-echo-time MRS of childhood cerebellar tumours. Single-voxel MRS (1.5-T Siemens Symphony NUM4, TR/TE 1,500/30 ms) was performed at presentation in 30 children with cerebellar tumours. The MRS results were analysed for comparison with histological diagnosis. Peak heights for N-acetyl aspartate (NAA), creatine (Cr), choline (Cho) and myo-inositol (mIns) were determined and receiver operator characteristic curves used to select ratios that best discriminated between the tumour types. The method was implemented by a group of clinicians and scientists, blinded to the results. A total of 27 MRS studies met the quality control criteria. NAA/Cr >4.0 distinguished all but ...

2007-11-15

130

The mammalian neuroendocrine hormone norepinephrine supplies iron for bacterial growth in the presence of transferrin or lactoferrin.  

Science.gov (United States)

Norepinephrine stimulates the growth of a range of bacterial species in nutritionally poor SAPI minimal salts medium containing 30% serum. Addition of size-fractionated serum components to SAPI medium indicated that transferrin was required for norepinephrine stimulation of growth of Escherichia coli. Since bacteriostasis by serum is primarily due to the iron-withholding capacity of transferrin, we considered the possibility that norepinephrine can overcome this effect by supplying transferrin-bound iron for growth. Incubation with concentrations of norepinephrine that stimulated bacterial growth in serum-SAPI medium resulted in loss of bound iron from iron-saturated transferrin, as indicated by the appearance of monoferric and apo- isoforms upon electrophoresis in denaturing gels. Norepinephrine also caused the loss of iron from lactoferrin. The pharmacologically inactive metabolite norepinephrine 3-O-sulfate, by contrast, did not result in iron loss from ...

2000-11-01

131

Response of photosynthesis, starch and sucrose synthesis to increased CO sub 2 and lowered O sub 2  

Energy Technology Data Exchange (ETDEWEB)

Increasing photosynthesis rate by raising CO{sub 2} and lowering O{sub 2} usually results in measured rates lower than those expected from the kinetics of rubisco. The failure of leaves to utilize the increased efficiency of rubisco has been attributed to limitations in rates of either starch or sucrose synthesis, which lead to a lowering of Pi and a reduction in the rate of ATP synthesis. In sugar beet leaves, increasing CO{sub 2} from 350 to 600 {mu}L L{sup {minus}1} usually increased photosynthesis only about 10%, compared to the 45% expected, and lowering O{sub 2} from 2 to 21% increased photosynthesis only an additional 20%, compared to the additional 40% expected. In some cases, raising CO{sub 2} increased photosynthesis the full 30% with no further increase occurring upon lowering O{sub 2}. In all cases, rates of starch and sucrose synthesis consistently increased in proportion to increasing photosynthesis rate. Metabolites that are predominantly cytosolic ...

1990-05-01

132

Redistribution and increased brain uptake of lead in rats after treatment with diethyldithiocarbamate  

International Nuclear Information System (INIS)

Diethyldithiocarbamate (DDTC), a chelating agent, is an active metabolite of disulfiram (Antabus) and is used in the rubber industry. The effect of DDTC on the tissue distribution of "2"0"3Pb was studied in rats. Two groups of rats were given an i.v. injection of 100 #mu#Ci "2"0"3Pb (28.6 nmol/kg b.wt.) as lead acetate. After 10 min one group received 2 mmol/kg b.wt. of DDTC as an i.p. injection. Rats were killed 4 and 72 h after injection of "2"0"3Pb and tissue concentration and excretion of "2"0"3Pb was determined by gamma counting. The brain concentration of "2"0"3Pb in DDTC-treated rats was nine times higher than in controls after 4 h and 14 times higher after 72 h. Treatment with DDTC also increased the lead concentration in fat about seven times at both survival intervals. On the other hand, uptake of "2"0"3Pb in bone was reduced by treatment with DDTC and at 4 h also kidney and blood had a lower concentration of "2"0"3Pb in DDTC-treated rats compared to ...

133

Punica granatum peel extract protects against ionizing radiation-induced enteritis and leukocyte apoptosis in rats  

International Nuclear Information System (INIS)

Radiation-induced enteritis is a well-recognized sequel of therapeutic irradiation. Therefore we examined the radioprotective properties of Punica granatum peel extract (PPE) on the oxidative damage in the ileum. Rats were exposed to a single whole-body X-ray irradiation of 800 cGy. Irradiated rats were pretreated orally with saline or PPE (50 mg/kg/day) for 10 days before irradiation and the following 10 days, while control rats received saline or PPE but no irradiation. Then plasma and ileum samples were obtained. Irradiation caused a decrease in glutathione and total antioxidant capacity, which was accompanied by increases in malondialdehyde levels, myeloperoxidase activity, collagen content of the tissue with a concomitant increase 8-hydroxy-2'-deoxyguanosine (an index of oxidative DNA damage). Similarly, pro-inflammatory cytokines (TNF-?, IL-1? and IL-6) and lactate dehydrogenase were elevated in irradiated groups as compared to control. PPE treatment reversed all these ...

2009-07-01

134

Prostaglandin (PG) E3 synthesis elicted by adrenergic stimuli in guinea-pig trachea (GPT) is mediated primarily by B2 adrenergic receptors  

Science.gov (United States)

The purpose of this study was to examine arachidonic acid (AA) metabolism and to characterize the type of adrenergic receptor (AR) involved in the production of the major metabolite of this fatty acid. ({sup 14}C)AA was incubated with GPT-rings and the radiolabelled products were extracted and separated by TLC method. The medium was also assayed for radiolabelled immunoreactive PG's (iPG's) and leukotrienes (LT) B4 and C4 by RIA or Enzyme immunoassay (EIA) after exposure to various AR agonists. ({sup 14}C)AA was incorporated into GPT-rings and metabolized mainly into iPGE2 and smaller amounts into PGF2{alpha}. Trace amounts of PGD2 and 6-keto-PGF1{alpha} but not LTB4 or LTC4 were detected by RIA and/or EIA. Incubation of GPT rings for 15 minutes with isoproterenol and salbutamol resulted in a significant increase of PGE2 synthesis (optimum conc: 10{sup {minus}7}, 10{sup {minus}7}M respectively). In contrast, dobutamine, norepinephrine, ...

1990-02-26

135

Prostaglandin (PG) E3 synthesis elicted by adrenergic stimuli in guinea-pig trachea (GPT) is mediated primarily by B2 adrenergic receptors  

International Nuclear Information System (INIS)

The purpose of this study was to examine arachidonic acid (AA) metabolism and to characterize the type of adrenergic receptor (AR) involved in the production of the major metabolite of this fatty acid. ["1"4C]AA was incubated with GPT-rings and the radiolabelled products were extracted and separated by TLC method. The medium was also assayed for radiolabelled immunoreactive PG's (iPG's) and leukotrienes (LT) B4 and C4 by RIA or Enzyme immunoassay (EIA) after exposure to various AR agonists. ["1"4C]AA was incorporated into GPT-rings and metabolized mainly into iPGE2 and smaller amounts into PGF2#alpha#. Trace amounts of PGD2 and 6-keto-PGF1#alpha# but not LTB4 or LTC4 were detected by RIA and/or EIA. Incubation of GPT rings for 15 minutes with isoproterenol and salbutamol resulted in a significant increase of PGE2 synthesis (optimum conc: 10"-"7, 10"-"7M respectively). In contrast, dobutamine, norepinephrine, phenylnephrine and xylazine (up to 10"-"6M) did not ...

1991-04-21

136

Production of Shiga-like toxins by Escherichia coli O157:H7 can be influenced by the neuroendocrine hormone norepinephrine.  

Science.gov (United States)

To examine whether the neuroendocrine hormone norepinephrine may influence the production of the Shiga-like toxins (SLTs), several Escherichia coli O157:H7 clinical isolates were grown in the presence or absence of norepinephrine. An in vitro culture system consisting of low (<1500 colony-forming units/ml) initial concentrations of inocula into a serum-based medium was used to more closely approximate in vivo conditions. The growth of all isolates was increased several logs in the presence of norepinephrine, as compared with the growth in controls, during a 24-hour growth period. Controls included additional dextrose as well as the use of the norepinephrine metabolite normetanephrine, which contains one more methyl group than norepinephrine and hence would serve as a better energy source for growth if the effect were solely nutritionally mediated. During the 24 hours of growth, the production of cell-associated SLT-I on a protein-equivalent basis was shown to be ...

1996-10-01

137

Population dynamics of dechlorinators and factors affecting the level and products of PCB dechlorination in sediments  

Energy Technology Data Exchange (ETDEWEB)

Microbial dechlorination of polychlorinated biphenyls (PCBs) often stops although a significant number of removable chlorines remain. To determine the reason for the cessation, we investigated the limitation of organic carbon, PCB bioavailability, and inhibition by metabolic products. Enrichment with carbon sources did not induce additional chlorination, indicating the plateau was not due to depletion of organic carbon. The bioavailability was not limiting, since a subcritical micelle concentration of the surfactant, which enhanced desorption without inhibiting dechlorinating microorganisms, failed to lower the plateau. Neither was it due to accumulation of metabolites, since no additional dechlorination was detected when plateau sediments were incubated with fresh medium. Similarly, dechlorination was not inhibited in freshly spiked sediment slurries. Dechlorination ended up at the same level with nearly identical congener profiles, regardless of treatment. These ...

1996-12-31

138

Polycyclic Aromatic Hydrocarbon (PAH) Exposure and DNA Adduct Semi-Quantitation in Archived Human Tissues  

Science.gov (United States)

Polycyclic aromatic hydrocarbons (PAHs) are combustion products of organic materials, mixtures of which contain multiple known and probable human carcinogens. PAHs occur in indoor and outdoor air, as well as in char-broiled meats and fish. Human exposure to PAHs occurs by inhalation, ingestion and topical absorption, and subsequently formed metabolites are either rendered hydrophilic and excreted, or bioactivated and bound to cellular macromolecules. The formation of PAH-DNA adducts (DNA binding products), considered a necessary step in PAH-initiated carcinogenesis, has been widely studied in experimental models and has been documented in human tissues. This review describes immunohistochemistry (IHC) studies, which reveal localization of PAH-DNA adducts in human tissues, and semi-quantify PAH-DNA adduct levels using the Automated Cellular Imaging System (ACIS). These studies have shown that PAH-DNA adducts concentrate in: basal and supra-basal epithelium of the ...

2011-07-29

139

Molecular mechanisms of the epithelial transport of toxic metal ions, particularly mercury, cadmium, lead, arsenic, zinc, and copper. Progress report, January 1, 1979-December 31, 1979  

International Nuclear Information System (INIS)

The mechanism of lead transport is presented, and especially the particular similarities or dissimilarities between lead and calcium in this process. The absorption of these metals was determined cockerels, raised on a commercial diet or on a specified diet, using in vivo ligated loop procedure. The dose administered into the loop contained 0.5 #mu#Ci "2"0"3Pb (and/or 0.1 #mu#Ci "4"7Ca), and 0.01 mM lead acetate (and/or mM CaCl_2) in 0.5 ml 0.15 M NaCl,pH 6.5. It was shown that lead is rapidly taken up by the mucosal tissue, and slowly transferred into the body, whereas less calcium is retained by the tissue and the transfer of calcium is many times as effective as that for lead. They appear to respond in a similar manner to a low calcium intake and vitamin D treatment. Increasing luminal stable lead concentration significantly reduced the percentage of radiolead significantly reduced the percentage of radiolead absorbed, but did not affect the absorption of calcium. Also, vitamin D ...

140

Modeling and laboratory investigations of microbial oil recovery mechanisms in porous media  

Energy Technology Data Exchange (ETDEWEB)

Simulation and experimental results on the transport of microbes and nutrients in one-dimensional cores are presented, and the development of a three-dimensional, three-phase, multiple-component numerical model to describe the microbial transport and oil recovery in porous media is described. The change of rock's wettability and associated relative permeability values after microbial treatments were accounted for in the model for additional oil recovery. Porosity and permeability reductions due to cell clogging have been considered and the production of gas by microbial metabolism has been incorporated. Governing equations for microbial and nutrient transport are coupled with continuity and flow equations under conditions appropriate for a black oil reservoir. The computer simulator has been used to determine the effects of various transport parameters on microbial transport phenomena. The model can accurately describe the observed transport of microbes, nutrients, and ...

1992-12-01

 
 
 
 
141

Modeling and laboratory investigations of microbial oil recovery mechanisms in porous media  

Energy Technology Data Exchange (ETDEWEB)

Simulation and experimental results on the transport of microbes and nutrients in one-dimensional cores are presented, and the development of a three-dimensional, three-phase, multiple-component numerical model to describe the microbial transport and oil recovery in porous media is described. The change of rock`s wettability and associated relative permeability values after microbial treatments were accounted for in the model for additional oil recovery. Porosity and permeability reductions due to cell clogging have been considered and the production of gas by microbial metabolism has been incorporated. Governing equations for microbial and nutrient transport are coupled with continuity and flow equations under conditions appropriate for a black oil reservoir. The computer simulator has been used to determine the effects of various transport parameters on microbial transport phenomena. The model can accurately describe the observed transport of microbes, nutrients, and ...

1992-12-01

142

Metabolic fate of chlorinated paraffins  

Energy Technology Data Exchange (ETDEWEB)

The disposition of three (1-/sup 14/C)-chlorododecanes (MCDD, PCDD I and PCDD II; 17.4%, 55.9%, and 68.5% chlorination) was studied in C57Bl mice. (1-/sup 14/C)-lauric acid (LA) was studied as reference compound. Fifty-two percent (MCDD), 32% (PCDD I), and 8% (PCDD II) of the radioactive doses were exhaled as /sup 14/CO/sub 2/ during 12 h after i.v. injection. Similar results were obtained after p.o. administration. In addition to a marked labelling of the liver and fat, the distribution patterns observed at 24 h after administration revealed an uptake of radioactivity in tissues with high cell turnover/high metabolic activity, e.g., intestinal mucosa, bone marrow, salivary glands and thymus. The concentration of radioactivity in these sites and the exhalation of /sup 14/CO/sub 2/, which were inverse to the degree of chlorination, indicate that the chloroalkanes are degraded to metabolites which can be utilized in the intermediary metabolism. A similar, although ...

1982-09-01

143

Kinetic analysis of transport and opioid receptor binding of ( sup 3 H)(-)-cyclofoxy in rat brain in vivo: Implications for human studies  

Energy Technology Data Exchange (ETDEWEB)

(3H)Cyclofoxy (CF: 17-cyclopropylmethyl-3,14-dihydroxy-4,5-alpha-epoxy-6-beta-fluoromorp hinan) is an opioid antagonist with affinity to both mu and kappa subtypes that was synthesized for quantitative evaluation of opioid receptor binding in vivo. Two sets of experiments in rats were analyzed. The first involved determining the metabolite-corrected blood concentration and tissue distribution of CF in brain 1 to 60 min after i.v. bolus injection. The second involved measuring brain washout for 15 to 120 s following intracarotid artery injection of CF. A physiologically based model and a classical compartmental pharmacokinetic model were compared. The models included different assumptions for transport across the blood-brain barrier (BBB); estimates of nonspecific tissue binding and specific binding to a single opiate receptor site were found to be essentially the same with both models. The nonspecific binding equilibrium constant varied modestly in different brain ...

1991-03-01

144

Isotope effects on the metabolism and pulmonary toxicity of butylated hydroxytoluene in mice by deuteration of the 4-methyl group  

Energy Technology Data Exchange (ETDEWEB)

A comparative test in mice for pulmonary toxicity between butylated hydroxytoluene (2,6-di-tert.-butyl-4-methylphenol, BHT) and 2,6-di-tert.-butyl-4-(alpha, alpha, alpha-2H3)methylphenol (BHT-d3) showed a significantly lower toxic potency of the latter. The rate of in vitro BHT metabolism to 2,6-di-tert.-butyl-4-methylene-2,5-cyclohexadienone (BHT-QM) was slowed by deuterating BHT in the 4-methyl group. On the other hand, the rate of in vitro metabolism to 2,6-di-tert.-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone (BHT-OH) was increased with the deuteration. A similar isotope effect of the deuterium substitution on the in vivo metabolic rates of BHT was observed. These observations support the concept that the lung damage caused by BHT is mediated by BHT-QM. The pulmonary toxicity of 2-tert.-butyl-4-ethylphenol (4-EP) and their deuterated analogs was also compared. 2-tert.-Butyl-4-(1,1-2H2)ethylphenol (4-EP-d2) showed a significantly lower toxic potency than 4-EP, whereas ...

1983-06-30

145

Isoprenylation is required for the processing of the lamin A precursor  

Energy Technology Data Exchange (ETDEWEB)

The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic for mevalonate. Moreover, inhibition of prelamin A processing by mevinolin treatment is rapidly reversed by the addition of exogenous mevalonate. Processing of prelamin A is, therefore, dependent on isoprenoid metabolism. Analysis of the conversion of prelamin A ...

1990-05-01

146

Intracellular concentrations and metabolism of carbon compounds in tobacco callus cultures: Effects of light and auxin  

Energy Technology Data Exchange (ETDEWEB)

Callus cultures derived from pith tissue of Nicotiana tobacum were grown on two media either under continuous illumination or in complete darkness. The first medium limited greening ability of callus grown in the light (3 milligrams per liter naphthalene acetic acid, 0.3 milligram per liter 2-isopentenylaminopurine, Murashige and Skoog salts, and 2% sucrose). The second medium encouraged chlorophyll synthesis (greening) though not shoot formation (0.3 milligram per liter naphthalene acetic acid; 0.3 milligrams per liter 2-isopentylaminopurine). To measure intracellular concentrations, calli were grown for 15 days on these standard media containing (U-/sup 14/C)sucrose. The dry weight proportions of the calli (as a fraction of fresh weight) and many metabolite concentrations nearly doubled in light-grown cells compared to dark-grown cells and increase 30 to 40% on low-auxin media relative to high-auxin media. Glutamine concentrations (from 4 to 26 millimolar) were ...

1981-10-01

147

Gastrointestinal absorption of lead in chicks: involvement of the cholecalciferol endocrine system  

Energy Technology Data Exchange (ETDEWEB)

The role of dietary calcium and phosphorus in modifying the intestinal absorption of lead and also the effect of lead ingestion on the metabolism of cholecalciferol were studied in chicks. The efficiency of absorption of /sup 203/Pb and /sup 47/Ca was increased when the animals were fed a low calcium diet and treated with cholecalciferol. The synthesis of the vitamin D-induced calcium-binding protein (CaBP) was correspondingly increased. When the chicks were depleted of vitamin D and repleted with 1,25-dihydroxycholecalciferol (1,25(OH)/sub 2/D/sub 3/) as their only source of the vitamin, the absorption of both /sup 47/Ca and /sup 203/Pb was unaffected by dietary calcium levels, and no change in CaBP levels occurred. Low dietary intake of phosphorus resulted in an increase in /sup 47/Ca and /sup 203/Pb absorption and in CaBP synthesis when the animals were treated with cholecalciferol. However, when the birds were repleted with 1,25(OH)/sub 2/D/sub 3/, the intestinal absorption of /sup ...

1984-04-01

148

Gastrointestinal absorption of lead in chicks: involvement of the cholecalciferol endocrine system  

International Nuclear Information System (INIS)

The role of dietary calcium and phosphorus in modifying the intestinal absorption of lead and also the effect of lead ingestion on the metabolism of cholecalciferol were studied in chicks. The efficiency of absorption of "2"0"3Pb and "4"7Ca was increased when the animals were fed a low calcium diet and treated with cholecalciferol. The synthesis of the vitamin D-induced calcium-binding protein (CaBP) was correspondingly increased. When the chicks were depleted of vitamin D and repleted with 1,25-dihydroxycholecalciferol [1,25(OH)_2D_3] as their only source of the vitamin, the absorption of both "4"7Ca and "2"0"3Pb was unaffected by dietary calcium levels, and no change in CaBP levels occurred. Low dietary intake of phosphorus resulted in an increase in "4"7Ca and "2"0"3Pb absorption and in CaBP synthesis when the animals were treated with cholecalciferol. However, when the birds were repleted with 1,25(OH)_2D_3, the intestinal absorption of "4"7Ca and of "2"0"3Pb was increased, as well ...

149

Evaluation of indexes for tumor growth and effect of radiation therapy using MRS; Experimental studies on SCCVII tumor bearing mice  

Energy Technology Data Exchange (ETDEWEB)

Changes in the phosphate metabolism of the transplanted SCCVII (squamous cell carcinoma VII) tumor were studied before and after irradiation using in vivo [sup 31]P-magnetic resonance spectroscopy (MRS). Phosphocreatine (PCr), [gamma]-, [alpha]-, [beta]-ATP, inorganic phosphate (Pi), phosphomonoester (PME), and phosphodiester (PDE) were detected in [sup 31]P-MR spectra of tumor tissues. The curve fitting method was employed for calculating each peak of [sup 31]P-MR spectra (PCr, [beta]-ATP, Pi, PME, PDE). The values of PCr, PCr/Pi, [beta]-ATP/Pi and pH decreased in proportion to the growth of tumor, whereas that of Pi, PME and PDE increased. But the changes of [beta]-ATP were minimal in degree. Based on the fact that the ratio of PCr/Pi highly correlated with tumor volume and showed the most remarkable change among various parameters, it might be the useful index for the tumor growth. Because the phospholipid metabolite PME was detected in the earlier stage of ...

1992-03-01

150

Ethanol production and a case study of ethanol produced from sweet sorghum stalks via solid state fermentation  

Energy Technology Data Exchange (ETDEWEB)

Ethanol has excellent fuel properties, such as high octane, high heat of vaporization and low photochemical reactivity in the atmosphere. It is less volatile than gasoline and there is lower smog formation from evaporative emissions of pure ethanol compared to gasoline. As such, ethanol has emerged as an important alternative energy source that is sustainable, efficient, cost effective, convenient and safe. In 2006, global production of ethanol reached 13.5 billion gallons, up from 12.1 billion gallons in 2005. However, in light of the current debate of food versus fuel, the industry must shift to non-food feedstocks. This paper described an emerging technology to cost-effectively produce ethanol from sweet sorghum stalks, the most promising alternative feedstock to corn, via solid state fermentation (SSF). Experiments of advanced solid state fermentation (ASSF) for ethanol production from sweet sorghum by Saccharomyces cerevisiae were conducted in laboratory and pilot scales studies. ...

2008-07-01

151

Determination of volatile metabolites originating from mould growth on wall paper and synthetic media.  

Science.gov (United States)

Microbial volatile organic compounds (MVOCs) emitted from the mould species Penicillium expansum, P. chrysogenum, Aspergillus versicolor, A. fumigatus, A. niger and Cladosporium cladosporoides were analyzed by means of solid phase microextraction (SPME) and GCMS. The mould species were cultivated on the synthetic agar dichloran chloramphenicol (DG 18) and on wet wall paper. The production of MVOCs was monitored over several weeks to detect changes in the emission rates between the initial stage and later periods of growth. The cultivation on the synthetic agar resulted in MVOC patterns with a wide variety of signals. In contrast, the growth on wet wall paper led to changed MVOC patterns with less signals. The emission rates were drastically reduced. Components emitted by all six fungi species on wall paper were 2-pentanol and 2-pentanone. 1-Octen-3-ol was emitted by five fungi species. 2-Pentanol was only detected in considerable amounts during the first days of growth whereas ...

2008-06-05

152

Anaerobic thermophilic bacteria isolated from a Venezuelan oil field and its potential use in microbial improved oil recovery  

Energy Technology Data Exchange (ETDEWEB)

The objective of this work is to determine the ability of indigenous bacteria from a Venezuelan oil field to grow under reservoir conditions inside a porous media, and to produce metabolites capable of recovering residual crude oil. For this purpose, samples of formation waters from a central-eastern Venezuelan oil reservoir were enriched with different carbon sources and a mineral basal media. Formation water was used as a source of trace metals. The enrichments obtained were incubated at reservoir temperature (71{degrees}C), reservoir pressure (1,200 psi), and under anaerobic conditions for both outside and inside porous media (Berea core). Growth and metabolic activity was followed outside porous media by measuring absorbance at 660 nm, increases in pressure, and decreases in pH. Inside porous media bacterial activity was determined by visual examination of the produced waters (gas bubbles and bacterial cells). All the carbohydrates tested outside porous media ...

1995-12-31

153

An Arabidopsis thaliana methyltransferase Capable of Methylating Farnesoic Acid  

Energy Technology Data Exchange (ETDEWEB)

We previously reported the identification of a new family of plant methyltransferases (MTs), named the SABATH family, that use S-adenosyl-l-methionine (SAM) to methylate a carboxyl moiety or a nitrogen-containing functional group on a diverse array of plant compounds. The Arabidopsis genome alone contains 24 distinct SABATH genes. To identify the catalytic specificities of members of this protein family in Arabidopsis, we screened recombinantly expressed and purified enzymes with a large number of potential substrates. Here, we report that the Arabidopsis thaliana gene At3g44860 encodes a protein with high catalytic specificity towards farnesoic acid (FA). Under steady-state conditions, this farnesoic acid carboxyl methyltransferase (FAMT) exhibits K{sub M} values of 41 and 71 {mu}M for FA and SAM, respectively. A three-dimensional model of FAMT constructed based upon similarity to the experimentally determined structure of Clarkia breweri salicylic acid methyltransferase (SAMT) ...

2006-01-01

154

Altered lauric acid metabolism in renal microsomes from spontaneously hypertensive rats (SHR)  

International Nuclear Information System (INIS)

Studies investigated whether changes in omega- and (omega-1)-hydroxylation (OH) of lauric acid (LA) occurred in renal microsomes prepared from SHR compared to Wistar-Kyoto (WK) control rats. Systolic blood pressure in age-matched adult SHR and WKR were 189 +/- 3 and 123 +/- 4 mm Hg(anti X +/- SE) respectively (p < 0.001). No significant differences between SHR and WKR were seen in body weight, kidney weight or renal microsomal protein content. Renal microsomes, prepared from whole kidneys, were incubated with 10 mM NADPH and ["1"4C]LA at concentrations between 5-50 #mu#M. The 11- and 12-OH metabolites of LA were separated by HPLC using a reverse phase column with a methanol:water:acetic acid (62:37.8:0.2) mobile phase. Apparent (app) V/sub max/ values for 12-OH in WKR and SHR were 0.87 +/- 0.19 vs 1.48 +/- .11 nmoles/mg protein/min (p < 0.05), respectively, while values for 11-OH were 0.51 +/- 0.12 vs 0.60 +/- .07, respectively. No significant differences ...

1986-04-13