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PubMed1998

Induction and inhibition of cytochrome P450-catalysed reduction of biologically active benfluron N-oxide.

Benfluron N-oxide [5-(2-N-oxo-2-N,N'-dimethylaminoethoxy)-7-oxo-7-H-benzo[c]fluorene] is a biologically active substance which displays a cytostatic effect on several experimental tumour cells. The main metabolic pathway of benfluron N-oxide in vitro and in vitro--its reduction to the parent tertiary amine benfluron--and the role of cytochrome P450 in this reduction were studied. The value of the benfluron N-oxide/benfluron redox potential as a criterion of suitability of the substrate for cytochrome P450 reductase activity was determined. Results of induction and inhibition studies on rats suggest that cytochromes P4502B and P4502E1 participate in microsomal reduction of benfluron N-oxide. Unlike most cytochrome P450 catalysed reactions, the reduction of benfluron N-oxide also occurs under aerobic conditions. Microsomes induced by phenobarbital, ethanol or beta-naphthoflavone showed no significantly greater inhibitory effect of oxygen on benfluron N-oxide reduction.

Animals↗
PubMed2003

The unique aromatic catabolic genes in sphingomonads degrading polycyclic aromatic hydrocarbons (PAHs).

Many members of the sphingomonad genus isolated from different geological areas can degrade a wide variety of polycyclic aromatic hydrocarbons (PAHs) and related compounds. These sphingomonads such as Sphingobium yanoikuyae strain B1, Novosphingobium aromaticivorans strain F199, and Sphingobium sp. strain P2 have been found to possess a unique group of genes for aromatic degradation, which are distantly related with those in pseudomonads and other genera reported so far both in sequence homology and gene organization. Genes for aromatics degradation in these sphingomonads are complexly arranged; the genes necessary for one degradation pathway are scattered through several clusters. These aromatic catabolic gene clusters seem to be conserved among many other sphingomonads such as Sphingobium yanoikuyae strain Q1, Sphingomonas paucimobilis strain TNE12, S. paucimobilis strain EPA505, Sphingobium agrestis strain HV3, and Sphingomonas chungbukensis strain DJ77. Furthermore, some genes for naphthalenesulfonate degradation found in Sphingomonas xenophaga strain BN6 also share a high sequence homology with their homologues found in these sphingomonads. On the other hand, protocatechuic catabolic gene clusters found in fluorene-degrading Sphingomonas sp. strain LB126 appear to be more closely related with those previously found in lignin-degrading S. paucimobilis SYK-6 than the genes in this group of sphingomonads. This review summarizes the information on the distribution of these strains and relationships among their aromatic catabolic genes.

Alphaproteobacteria↗
PubMedDate not supplied

Biochemical basis for the resistance of guinea-pig and monkey to the carcinogenic effects of arylamines and arylamides.

1. Ag.l.c. assay for N-hydroxy-2-acetamidofluorene has been modified to measure both N-hydroxy-2-acetamidofluorene and N-hydroxy-2-aminofluorene. 2. Like guinea-pig, monkey N-hydroxylates both 2-aminofluorene and 2-acetamido-fluorene. The N-hydroxy metabolites are rapidly further metabolized even in the presence of inhibitors of deacetylase. The exact nature of this further metabolism is still unknown. Preliminary evidence indicates that, at least in the guinea-pig, 7-hydroxy-2-acetamidofluorene may be a metabolite of N-hydroxy-2-acetmidofluorene. 3. 3-Methylcholanthrene, 7,8-benzoflavone and miconazole, which have been shown to inhibit guinea-pig liver microsomal N-hydroxylase, do not significantly inhibit the monkey liver enzyme. 4. 2-Acetamidofluorene, which inhibits the guinea-pig liver microsomal N-hydroxylation of 2-aminofluorene in vitro, activates the enzyme from monkey liver. This activation, which is dose-dependent, appears to be allosteric. 5. Both guinea-pig and monkey are more efficient in N-hydroxylating 2-aminofluorene than 2-acetamidofluorene. The affinity (in term of apparent KM) of the guinea-pig liver enzyme is 4 times greater than the affinity of the monkey liver enzyme.

2-Acetylaminofluorene↗
PubMedDate not supplied

Diaminofluorene is more sensitive than benzidine for detecting hemoglobin in erythropoietin responsive J2E cells.

We have used the diaminofluorene stain to detect hemoglobin production in J2E cells following erythropoietin-induced differentiation. The pseudo-peroxidase activity of hemoglobin produces a colored product, fluorene blue, which can be measured spectrophotometrically. We found that the absorbance varied with time and concentration of hemoglobin, making it unsuitable for rapid, routine use. However, hemoglobin content could be determined from the initial reaction rate and this correlated extremely well with the number of benzidine positive cells. When used as a direct cytochemical stain diaminofluorene was shown to be more sensitive than benzidine in detecting hemoglobin-producing J2E cells.

Benzidines↗
PubMed1975

The carcinogenicity of fluorenylhydroxamic acids and N-acetoxy-N-fluorenylacetamides for the rat as related to the reactivity of the esters toward nucleophiles.

In extension of previous work indicating that the carcinogenicity of isomeric fluorenylhydroxamic acids depends on the point of attachment of the nitrogen atom on the fluorene system, the carcinogenicities of N-hydroxy-3-fluorenylacetamide and of N-hydroxy-4-fluorenylacetamide were evaluated in male and female Sprague-Dawley rats by several routes of administration and were compared with the carcinogenicity of N-hydroxy-2-fluorenylacetamide. The earlier observation that N-hydroxy-3-fluorenylacetamide is a specific mamary carcinogen was confirmed. N-Hydroxy-4-fluorenylacetamide was only marginally carcinogenic. Neither isomer gave tumors at the site after i.m. administration of the compounds into the hind leg of the rat. A comparison of the carcinogenicity of the isomers indicated the following order of activity: N-Hydroxy-2-fluorenylacetamide greater than N-hydroxy-3-fluorenylacetamide greater than N-hydroxy-4-fluorenylacetamide. Because of the current concept that arylhydroxamic acids are further acitvated to electrophilic reactants capable of interacting covalently with cellular nucleophiles and because esters of N-hydroxy-2-fluorenylacetamide give rise to an electrophilic reactant, the acetate esters of N-hydroxy-3-fluorenylacetamide and N-hydroxy-4-fluorenylacetamide were prepared and tested for their carcinogenicity in male and female Spaguw-Dawley rats by i.p. and i.m. administration. The order of carcinogenicity of the isomeric esters followed that of the parent hydroxamic acids (N-acetoxy-2-fluorenylacetamide greater than N-acetoxy-3-fluorenylacetamide greater than N-acetoxy-4-fluorenylacetamide). In order to correlate the carcinogeniciyt of the isomeric esters with their reactivity toward nucleophiles, the esters were reacted with methionine, transfer RNA, and the nucleosides, guanosine and adenosine. Under identical conditions, the reactivity of N-acetoxy-2-fluorenylacetamide towards methionine was at least tenfold greater than that of N-acetoxy-4-fluorenylacetamide. In addition to o-methylthio-2-fluorenylacemide, a new adduct, o-methylsulfoxo-2-fluorenylacetamide, was isolated from the reaction of N-acetoxy-2-fluorenylacetamide with methionine. Reaction of N-acetoxy-4-fluorenylacetamide and 1-methylthio-4-fluorenylacetamide. N-Acetoxy-3-fluorenylacetamide did not react with methionine. Continued.

Acetamides↗
PubMed1997

[Crystal and molecular structure of the antimalarial agent alpha-(dibutylaminomethyl)-2, 7-dichloro-9-(p-chlorobenzylidene)-4- fluorenemethanol(benflumetol)].

The three-dimensional crystal and molecular structure of benflumetol(I), alpha-(dibutylaminomethyl)-2, 7-dichloro-9-(p-chlorobenzylidene)-4-fluorenemethanol, was determined by X-ray crystallography and compared with the crystal structures of the cinchona alkaloids. The aromatic rings of fluorene-phenyl system of benflumetol are twisted from each other by 52.8 degrees. The torsion angle of N-C-C-O of benflumetol is 47.6 degrees. The intramolecular aliphatic N-O distance in benflumetol is 2.709A, which is close to the N-O distance found in antimalarial cinchona alkaloids. Benflumetol contains an intramolecular hydrogen bond between the aliphatic nitrogen and oxygen atoms, no intermolecular hydrogen bond was found, which is different from the known amino alcohol antimalarials.

Antimalarials↗
PubMed2000

[HPLC determination of PAHs from electric power plant by UVD-FLD connected in series].

An HPLC method of UVD-FLD connected in series was used to detect naphthalene, biphenyl, fluorene, phenanthrene, anthracene, fluoranthene, 2-methyl-anthracene, chrysene, benzanthracene, benzfluoranthene [b], benzfluoranthene[k], benzopyrene PAH compounds in electricity plant environment. A CLC-ODS column (150 mm x 6.0 mm i.d.) with acetonitrile-water(85:15, V/V) as mobile phase and UV detector set at 250 nm and fluorescent detector set at lambda ex295 nm and lambda em427 nm were used. These 12 PAHs can be separated completely by this method. The earlier eluted eight PAHs were detected by UVD and the rest were detected by FLD. The minimum detectable concentrations of the 12 PAHs were 0.002 mg/L-0.1 mg/L. Satisfactory results were obtained in the analysis of PAH compounds in waste water, flue gas and flyash from several electric power plant in Hunan Province.

Chromatography, High Pressure Liquid↗
PubMed1976

Lipid hydroperoxide activation of N-hydroxy-N-acetylaminofluorene via a free radical route.

The data presented here demonstrate that linoleic acid hydroperoxide in the presence of methemoglobin or hematin activated the carcinogen N-hydroxy-N-acetyl-2-amino-fluorene via the nitroxyl free radical intermediate into 2-nitrosofluorene and N-acetoxy-N-acetyl-2-aminofluorene. Ascorbate inhibited the activation, in which case the free radical intermediate was replaced by the ascorbate free radical. On the basis of optical kinetics, we have established that the rate of linoleic acid hydroperoxide decrease paraleled the rate of N-hydroxy-N-acetyl-2-aminofluorene decrease and also the rate of 2-nitrosofluorene increase. The stoichiometry of the reaction was such that, for every 2 linoleic acid hydroperoxide molecules consumed, 2 N-hydroxy-N-acetyl-2-aminofluorene molecules were oxidized and 1 2-nitrosofluorene and 1 N-acetoxy-N-acetyl-2 aminofluorene molecule was formed.

Ascorbic Acid↗
PubMedDate not supplied

Oxidation of aldose reductase inhibitors ALO-4114 and ALO-3152 catalyzed by liver microsomes.

Rat and Cynomolgus monkey liver microsomes catalyze the oxidation of 2.7-difluoro-4.5-dimethoxyspiro (9H-fluorene-9,4'-imidazolidine)-2',5'-dione (ALO-4114) to its monomethoxymetabolite (ALO-4417). Formation of this product by O-demethylation of ALO-4114 is catalyzed by NADPH and oxygen-dependent microsomal enzymes with the properties of P-450 monooxygenases. The reaction is blocked by inhibitors selective for these enzymes and activity increases about 2-fold in rats pretreated with phenobarbital or methylcholanthrene. The increase in the O-demethylation of ALO-4114 was, however, considerably less than the increase in benzphetamine N-demethylation or nitrophenetole O-deethylation activities in liver microsomes from rats pretreated with either phenobarbital or methylcholanthrene. Rats pretreated with 20 or 40 mg/kg of ALO-4114 for 3-4 days failed to change significantly the rate of ALO-4114 O-demethylase activity of liver microsomes. O-Demethylation of the achiral ALO-4114 yields the chiral ALO-4417. The enantiomers separated on a Daicel Chiracel AS column by HPLC indicated that O-demethylation of ALO-4114 by microsomes from untreated rats was only slightly stereoselective. However, rats pretreated with methylcholanthrene not only enhanced activity, but also increased the formation of one enantiomer. Further oxidative metabolism of the enantiomers was slow and barely detectable in vitro. Studies conducted with Cynomolgus monkey liver microsomes from one male and one female per experimental group were generally consistent with those from the rat, but some differences were noted. Whether the differences are real or only reflect individual variations caused by the small sample size is not known at present.

Aldehyde Reductase↗
PubMedDate not supplied

Sample preparation improvement in polycyclic aromatic hydrocarbons determination in olive oils by gel permeation chromatography and liquid chromatography with fluorescence detection.

The determination of 15 polycyclic aromatic hydrocarbons (PAHs) in olive oil samples has been improved in order to obtain a fast methodology with a low limit of detection through the combination of liquid-liquid extraction with acetonitrile and preparative gel permeation chromatography (GPC) prior to the injection of purified extracts into a C18 column. Acetonitrile-water was used as the mobile phase with a gradient from 50 to 95%, w/w, acetonitrile in 30 min. The oven temperature was maintained at 15 degrees C, and fluorometric detection was made at a fixed excitation wavelength of 264 nm and variable, optimal emission wavelength for each analyte ranging from 352 nm for 11-H-benzo(b)fluorene to 500 nm for indeno(1,2,3-cd)pyrene. Recovery for all the compounds studied varied from 75 to 111%, and limit of detection values from 0.05 ng/g for benzo(k)fluoranthene to 0.48 ng/g for indeno(1,2,3-cd)pyrene, corresponding to 0.09 ng/g benzo(a)pyrene. Results were compared with those obtained by liquid-liquid extraction followed by a cleanup on silica and a direct GPC treatment of oil samples diluted in dichloromethane, 2 other methodologies that are appropriate for quantifying PAHs in olive oils. However, the proposed method improves the determination limits, reduces the time of analysis, and provides a highly stable baseline for sample chromatograms.

Acetonitriles↗
PubMed1988

AL-1576, an aldose reductase inhibitor (ARI), did not prevent the decrease of norepinephrine turnover in diabetic rats.

ONO-2235 [(E)-3-carboxymethyl-5-[(2E)-2-methyl-3-phenyl-propenylidene]rhodanine], an ARI, was reported to prevent significantly the decrease of norepinephrine (NE) turnover in three tissues of streptozotocin (STZ)-diabetic rats (1). To examine whether the partial restoration of NE turnover by ONO-2235 is related to its ARI activity, the effect of another ARI, AL-1576 [spiro(2,7-difluoro-9H-fluoren-9, 4'-imidazoline)-2'5'-dione], on NE turnover in STZ rats was investigated. STZ caused an accumulation of sorbitol in the lens and decreased NE turnover in interscapular brown adipose tissue (IBAT), heart and pancreas. AL-1576 totally prevented the accumulation of sorbitol in the lens but had no effect on the decreased NE turnover in all three tissues. These results suggest that the partial prevention of NE turnover decrease by ONO-2235 may not have been mediated by its ARI activity.

Aldehyde Reductase↗
PubMed1977

Induction of lymphokines by tilorone.

Serum obtained 16 hr after p.o. application of tilorone [2, 7-bis/2-diethylaminoethoxy/-fluoren-9-one dihydrochloride] to ABD2F1 mice demonstrated both interferon and migration inhibitory (MIF) activity. Kinetic studies showed a close correspondence between interferon and MIF serum levels. The physiochemical characteristics of tilorone-induced MIF (heat and pH lability, molecular size) are compared with those of MIF generated in in vitro lymphocyte cultures. The findings are discussed in relation to production of lymphocytogenic lymphokines.

Animals↗
PubMed1987

Quantitation of erythroid differentiation in vitro using a sensitive colorimetric assay for hemoglobin.

We have developed a new colorimetric method to detect early erythroid clonogenic progenitor cells by virtue of their hemoglobin-containing progeny in vitro. The method relies upon the specific oxidation of 2,7-diaminofluorene (DAF) by the pseudoperoxidase activity of hemoglobin (Hb). Generation of fluorene blue (FB), the chromophore generated upon oxidation of DAF, was a linear function of Hb and erythrocyte concentration. Measurement of FB absorbance at 610 nm was 80 times more sensitive than measurement of Hb absorbance at 530 nm. The limit of resolution was approximately 8 pmol of Hb corresponding to the Hb content of approximately 5000 murine peripheral blood erythrocytes. FB concentration closely paralleled eight-day BFU-E colony formation as a function of erythropoietin dose. However, the method was unable to detect a response for CFU-E to erythropoietin because of persistently high background levels of Hb in two-day cultures. Generation of FB by cells likely to contain myeloperoxidase was negligible, and FB production was not correlated with the number of CFU-GM colonies. DAF oxidation by hemoglobin showed a higher hydrogen peroxide optimum than oxidation by microperoxidase, so that, under the conditions used, FB generation by peroxidase was not favored. As a further confirmation of specificity, peritoneal exudate cells failed to show significant generation of FB. The DAF reagent was also used to stain both CFU-E and BFU-E colonies in situ, and was more sensitive than benzidine dihydrochloride in the histochemical detection of Hb. DAF can replace hazardous benzidine-related compounds for the staining erythroid colonies in culture dishes, and the method offers a new quantitative approach to the study of erythropoietin responsiveness in vitro.

Animals↗
PubMed1987

Age-associated sensitivity to experimental, drug-induced marrow hypoplasia in laboratory rats.

Treatment of adult rats of three age groups (8, 11 and 29 weeks) with haematotoxic doses of three different cytostatic agents (cyclophosphamide, 5-(2-dimethyl-aminoethoxy)-7-oxo-7H-benzo(c)fluorene, and lomustine) demonstrated a tendency to lower the sensitivity of elder animals to cytotoxic effects. The influence of age was especially distinct in changes of the reticulocyte or segmented neutrophil counts after all drugs tested. Changes in marrow nucleated erythroid cell counts were not significantly influenced by age. Reactions of other characteristics also depended on this factor but not following the administration of every drug.

Abnormalities, Drug-Induced↗
PubMed1985

The effect of chrysene and some polycyclic aromatic hydrocarbons on the elimination of theophylline in rats.

The investigations of the effect of some compounds belonging to the group of polycyclic aromatic hydrocarbons (PAH), e. g. benzo[a]pyrene, chrysene, fluorene and pyrene, on the elimination of theophylline injected i. v. into rats have shown that benzo[a]pyrene and chrysene accelerate the elimination of this drug (elimination rate constant in control group: 0.2504 h-1; after benzo[a]pyrene: 0.3626 h-1; after chrysene: 0.3582 h-1). The increase of theophylline elimination rate constant by chrysene depends on its dose, and this relationship is of sigmoid type in the dose range of 1-20 mg X kg-1. Besides, dependence of theophylline elimination rate constant on the time of chrysene dosing was also shown. After oral administration of theophylline the decrease of its amount reaching the circulation by 11% was also observed, which was caused by the influence of chrysene on the first-pass effect, beside its influence on the elimination rate.

Animals↗
PubMed1977

[Tilorone, a synthetic immunostimulator possessing antitumor activity].

The authors report the results of studies on antitumor, immunostimulating and interieron-inducing properties of diethylamine fluorene derivative--tiloron, synthesized at Odessa laboratories of IGIC of the Ukrainian SSR Academy of Sciences by the originally elaborated method. It was found that tiloron does not suppress leucopoiesis, stimulates a number of protective reactions of the organism, including the factors of humoral and cell immunity, especially manifested under immunosuppression. Tiloron is shown to possess the definite antitumor activity being retained in peroral administration of the drug. Tiloron used together with cytostatic agents results in enhanced suppression of experimental tumors growth. Antitumor and immunostimulating action of tiloron on the experimental patterns under study is believed by the authors to be somewhat related with its interieron-inducing ability.

Animals↗
PubMed1975

Inhibition of purified DNA polymerase of RNA tumor viruses by fluoranthene derivatives and analogues of tilorone hydrochloride.

At concentrations of 7 times 10(-6) to 7 times 10(-5) M, derivatives consisting of the polycylic ring structures fluoranthene, fluorenone, fluorene, anthraquinone, xanthenone, and dibenzofuran with appropriate amine side chains inhibited by over 90% the purified RNA-directed DNA polymerase of avian myeloblastosis virus acting on poly(deoxyadenylate-deoxythymidylate) [poly(dA-dT)]. Of these, only the fluoranthene derivatives were strong inhibitors of the viral DNA polymerase directed by polyadenylate-oligodeoxythymidylate [poly(A)-(dT)12-18]. Low levels of fluoranthene derivatives (1 times 10(-5) M) also strongly inhibited polymerase with polyinosinate-oligodeoxycytidylate [poly(I)-(dC)12-18], activated calf thymus DNA, and viral 70S RNA as templates, but not with polycytidylate-oligodeoxyguanylate as template. A comparison of the activity of 11 fluoranthene derivatives with different side chains showed that the structure of the amine side chain influenced both the extent of antipolymerase activity with a given template and the relative inhibition with different synthetic DNA and RNA templates. The naturally occurring polyamines, spermine, spermidine, and putrescine, did not inhibit the activity of the viral DNA polymerase. Studies on the mechanism of action indicated that the synthetic derivatives inhibited polymerase activity by binding to the template and not to the enzyme: 1) inhibition by fluoranthene derivatives was overcome by the addition of excess template including poly(dA-dT), poly(A)-(dT)12-18, poly(I)-(dC)12-18, viral 70S RNA, and activated calf thymus DNA; 2) the degree of inhibition by fluoranthene derivatives was unaffected by the addition of the creased viral DNA polymerase; 3) with the same template, Escherichia coli DNA-directed RNA polymerase and the viral RNA-directed DNA polymerase were inhibited to about the same extent; and 4) the derivatives formed a complex with DNA, poly(I), and poly(A) that was stable to exclusion chromatography on Sephadex G-100. Several derivatives also had biologic activity, since they blocked the ability of the murine sarcoma virus to transform cells.

Anthraquinones↗
PubMed1976

2,7-Fluorenediamine and 2,5-fluorenediamine as peroxidase reagents for blood smears.

Our new histochemical methods for peroxidase activity, which do not require benzidine as a hydrogen donor, have been modified for hematological use. Diamine derivatives of fluorene (2,7-fluorenediamine and 2,5-fluorenediamine) were employed in place of benzidine and the result obtained was satisfactory. Two staining techniques were developed. (1) Smears of peripheral blood or bone marrow aspirates were fixed in 2.5 per cent glutaraldehyde solution for 1 minute. Smears were then washed in tap water and covered either by a saturated solution of 2,7-bluorenediamine or by a 0.05 per cent solution of 2,5-fluorenediamine in the presence of hydrogen peroxide for 5 minutes. After being washed in running tap water they were counterstained with Carazzi's hematoxylin solution for 10 minutes. (2) The second technique employs pretreatment of blood smears with 5 per cent CuSO4 solution and aldehyde fixation was omitted. Smears were counterstained by Giemsa stain. The nuclear chromatin structures were well preserved and nucleoli were easily distinguished in the immature cells. In the first method, clear brown granules were recognized in the cytoplasms. In the second method, peroxidase-positive granules were stained black and the staining of nucleus and cytoplasm resembled that of McJunkin's method.

Blood↗