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PubMedDate not supplied

[Conditions for analysis of cytochrome p-450 activity in human liver microsomes].

Multiples forms of CYT-P450 have been isolated from human liver microsomes. The distribution of CYT-P450 could be correlated with pathologic and influence the individual's response to therapeutic drugs and susceptibility to the toxic and cancerogenic effects of environmental pollutants. The aim of the this work is to determine the amounts of CYT-P450's in small samples from human liver such as biopsies and eventually to correlate them with pathology. For these reasons, tests providing informations about the distribution of CYT-P450 in individual subjects are very important. In this study we have reviewed the method for measuring the activity of CYT-P450 and the dosage of Benzopyrene hydroxylase. We modified some of these methods for the study of CYT-P450 from human liver microsomes.

Cytochrome P-450 Enzyme System↗
PubMed2004

[Chemopreventive effect of resveratrol to cancer].

BACKGROUND & OBJECTIVE: Carcinogenesis is a complex process and at least 3 stages, including initiation, promotion, and progression, have been proposed in the process of carcinogenesis. Resveratrol has attracted considerable attention due to its low toxicity and unique chemical structure. This study was designed to test chemopreventive effect of resveratrol to cancer using various animal models. METHODS: Ames assay and micronucleus formation assay were used to test the antimutagenic activities of resveratrol. Croton oil-induced enhancement of ornithine decarboxylase (ODC) activities of dorsal epidermis cells in mouse and mouse ear edema model were used to investigate the anti-promotion effect of resveratrol. In addition,7,12-dimenthylbenz[a]anthracene (DMBA)/croton oil-induced mouse skin tumor model was used to evaluate chemopreventive effect of resveratrol to cancer in vivo. RESULTS: In Ames test,100 microg/plate of resveratrol exhibited 42.2% of inhibition on the reversion of Salmonella typhimurium TA100 induced by methylmethansulfonate, and 200 microg/plate of resveratrol exhibited 91.8% of inhibition on the reversion induced by benzopyrene. Pretreatment of resveratrol prevented cyclophosphamide (CTX)-induced micronucleus formation of polychromatic erythrocytes of mice bone marrow in dose-dependent manner. Mice treated with 30 mg/kg of resveratrol for 6 days before croton oil exposure have palliative ear edema. Treatment of 180 mg/kg resveratrol for 3 days caused 69.3% decrease of ODC activities in croton oil-induced dorsal epidermis. It was shown that resveratrol could inhibit DMBA/croton oil-induced mouse skin papilloma, which includes prolonging the latent period of tumor occurrence, decreasing the incidence of papilloma, and reducing tumor number per mouse in dose-dependent manner. CONCLUSION: Resveratrol has the ability of anti-mutation and anti-promotion of cancer and merit further studies as a potential cancer chemopreventive agent.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1992

Curcumin as an inhibitor of cancer.

Curcumin I (Cur I) and curcumin III (Cur III) are the yellow coloring phenolic compounds isolated from the spice turmeric. The effect of curcumins on different stages of development of cancer was studied. Cur I inhibited benzopyrene- (BP) induced forestomach tumors in female Swiss mice, and Cur III inhibited dimethylbenzanthracene- (DMBA) induced skin tumors in Swiss bald mice. Cur I also inhibited DMBA-initiated, tetradeconyl phorbol acetate-promoted skin tumors in female Swiss mice. In vitro 3H-BP-DNA interaction studies, and in vivo carcinogen metabolizing enzyme studies revealed that curcumins exert anticarcinogenic activity by altering the activation and/or detoxification process of carcinogen metabolism. Cur I and Cur III also exhibit in vitro cytotoxicity against human chronic myeloid leukemia, which is dose dependent. This study shows that curcumins inhibit cancer at initiation, promotion and progression stages of development.

Administration, Oral↗
PubMed2005

Studies on drug metabolizing enzymes during arteether treatment of Plasmodium yoelii nigeriensis infected mice cerebral microvessels.

Human cerebral malaria is caused by a protozoan parasitic with no cure till date. The isolation of brain capillaries i.e. microvessels has permitted the in vitro study related to cerebral function. Microvessels were isolated from normal and P. yoelii infected mice brain cortex and subjected to biochemical characterization by the following enzyme markers viz alkaline phosphatase, gamma-glutamyI transpeptidase and monoamine oxidase and electron microscopically. Limited studies have been carried out in relation to drug metabolizing enzymes in cerebral microvessels of rodents. The present studies have been carried out in relation to status of drug metabolizing enzymes during P. yoelii infection in cerebral microvessels of mice. The data obtained depicted a clear cut impairment of cytochrome P450 (a terminal monooxygenase) and related indices viz b5, benzopyrene hydroxylase, aminopyrene-n-demethylase, aniline hydroxylase except NADH cytochrome e reductase which increased during P. yoelii infection in mice as compared to normal. Further the oral drug administration (arteether) treatment brought back the altered MFO system normal a week alter cessation of drug treatment.

Animals↗
PubMedDate not supplied

Effects of low intensity static electromagnetic radiofrequency fields on leiomyosarcoma and smooth muscle cell lines.

In this study we investigated the effects of low intensity static radiofrequency electromagnetic field (EMF) causing no thermal effects, on leiomyosarcoma cells (LSC), isolated from tumors of fifteen Wistar rats induced via a 3,4-benzopyrene injection. Electromagnetic resonance frequencies measurements and exposure of cells to static EMF were performed by a device called multi channel dynamic exciter 100 V1 (MCDE). The LSC were exposed to electromagnetic resonance radiofrequencies (ERF) between 10 kHz to 120 kHz, for 45 min. During a 24h period, after the exposure of the LSC to ERF, there was no inhibition of cells proliferation. In contrast, at the end of a 48 h incubation period, LSC proliferation dramatically decreased by more than 98% (P<0.001). At that time, the survived LSC were only 2% of the total cell population exposed to ERF, and under the same culture conditions showed significant decrease of proliferation. These cells were exposed once again to ERF for 45 min (totally 4 sessions of exposure, of 45 min duration each) and tested using a flow cytometer. Experiments as above were repeated five times. It was found that 45% of these double exposed to ERF, LSC (EMF cells) were apoptotic and only a small percentage 2%, underwent mitosis. In order to determinate their metastatic potential, these EMF cells were also counted and tested by an aggregometer for their ability to aggregate platelets and found to maintain this ability., since they showed no difference in platelet aggregation ability compared to the LSC not exposed to ERF (control cells). In conclusion, exposure of LSC to specific ERF, decreases their proliferation rate and induces cell apoptosis. Also, the LSC that survived after exposed to ERF, had a lower proliferation rate compared to the LSC controls (P<0.05) but did not loose their potential for metastases (platelet aggregation ability). The non-malignant SMC were not affected by the EMF exposure (P<0.4). The specific ERF generated from the MCDE electronic device, used in this study, is safe for humans and animals, according to the international safety standards.

Animals↗
PubMed1991

[Comparative analysis of oncological morbidity in the population of an industrial city and workers of a metallurgical plant].

Analytical epidemiology techniques were used to study the malignant neoplasms prevalence in the population of Magnitogorsk (400,000), and among the workers engaged in the Magnitogorsk metallurgical plant (64,000 workers). Revealed was that the malignant neoplasms related morbidity rate was 1.6 higher in men and 3.2 higher in women among the plant workers as compared with the city population in general. The cancer risk factors were predominantly occupational ones, e. i. the major industrial carcinogens--benzopyrene in tars and carbon-black; benzol, chromium and nickel in the dust; the carcinogenesis modifying substances--nitrogen oxide, sulfur dioxide, phenols, iron oxides, lead and its non-organic compounds, high temperatures. The data received can be used in further studies and elaboration of primary preventive measures.

Air Pollutants, Occupational↗
PubMedDate not supplied

[Evaluation of the binding of benzo-a-pyrene by blood serum lipoproteins using the cellulose disk method].

A simple and convenient method has been developed for evaluation binding capacity of lipophilic ligands with lipoproteins or other transport proteins. For this purpose cellulose discs (Whatman 3 MM) were loaded with the constant quantity of 3H-benzopyrene and increasing amounts of unlabelled benzo[a]pyrene in dimethylsulfoxide, dried up and incubated in solution of lipoproteins. Dissociation constants were deduced from the remained disk radioactivity using the Scatchard plot method. The obtained values of the dissociation constants were: HDL--4.1 x 10(-5) M; LDL--1.5 x 10(-6) M; VLDL--8.8 x 10(-6) M.

Animals↗
PubMed1991

[Injury to the immune system by food contaminated by environmental toxins].

Immunity may be used as bioindicator for environmental toxic substances: Low level concentration of Pb, Cd, nitrosamines, Benzopyrene, nicotine and saturated fatty acids in food lead after application over months to a reduction of cellular and humoral immune response. After challenge by different infectious agents mortality was higher in the experimental group of mice. Up to date, investigations with low level doses of toxic agents in food running over a longer time had not been performed.

Animals↗
PubMed1991

[Blastomogenic action of heavy vanadium-rich petroleum and its processing products].

The contributors performed a study of the blastomogenic properties of the heavy high vanadium oil processed at different temperatures. Skin applications of the oil and oil products in hybrid mice induced skin tumours in 27.5 (48.7%), pregastric--6.4 (7.6%), genital--15.4 (21.1%) cases. It was established that high temperatures of oil sublimation increased the benzopyrene contents and the oil products' blastomogenic activity.

Animals↗
PubMed1990

Chromosome and gene rearrangements in immortalized human lymphocytes infected with human T-lymphotropic virus type I.

Karyotypes of 26 human lymphocyte cultures, infected or noninfected with human T-lymphotropic virus type I (HTLV-I), with or without Epstein-Barr virus infection, were analyzed by G-banding. Hypodiploidy and structural abnormalities were seen more frequently in HTLV-I-infected cultures (30%) than in virus noninfected cultures (10%) propagated for less than 200 days. In all of six immortalized cell lines infected with HTLV-I alone or with both HTLV-I and Epstein-Barr virus, clonal chromosomal abnormalities characteristic for each cell line were observed in nearly 100% of cells examined after prolonged propagation. HTLV-I-infected interleukin 2-dependent T-cells acquired the ability to grow interleukin 2 independently after consecutive treatments with N-methyl-N'-nitro-N-nitrosoguanidine, 4-phorbol-12-myristate-13-acetate, and 1,2-benzopyrene. By Southern blot analysis of one T-cell line and three B-cell lines infected with HTLV-I alone or with HTLV-I and Epstein-Barr virus, rearrangements of the Jk gene were found in all B-cell lines, and rearrangements of the T-cell receptor beta gene were found in all cell lines regardless of their lineage. These results suggest that human lymphocytes undergo chromosome and gene rearrangements probably through an abnormal mitotic process caused by integration of HTLV-I proviral DNA, leading to the emergence of advantageous clones for growth. This process might be promoted synergetically by certain carcinogenic compounds present in the environment of HTLV-I-infected cells.

Cells, Cultured↗
PubMed1990

[Occupational pathology of the respiratory organs in miners of highly mechanized ore mines using diesel vehicles].

A medical survey of 2000 miners was performed at industrial sites using high-mechanized self-propelled diesel vehicles in the Far North, South and East regions of the country. All the miners were exhibited to quartz containing polymetal ore dusts and diesel exhausts. 128 miners were medically examined to specify the morphological changes in the bronchi and respiratory sections in case of occupational pathology, as well as to establish specific clinical manifestations. In 81 cases, fibro-bronchoscopy was performed and bronchial mucous and transbronchial pulmonary biopsy. Due to the increased concentrations of benzopyrene and other soot absorbed polycyclic hydrocarbons, thoron and radon, the authors tentatively proposed them as risk-factors for occupational malignant bronchopulmonary diseases development.

Adult↗
PubMed1989

Effect of fatty acids on formation, distribution, storage, and release of benzo(a)pyrene phenols and glucuronides in the isolated perfused rat liver.

The hydroxylation of benzo(a)pyrene and conjugation, storage, and release of benzo(a)pyrene phenols and glucuronides by the perfused rat liver were studied in the presence and absence of acute addition of physiological concentrations of common dietary fatty acids. The actions of fatty acids on the oxidation and conjugation of benzo(a)pyrene in the intact liver were compared with their actions on microsomes isolated from rat liver. Rats were treated with beta-naphthoflavone to stimulate polycyclic aromatic hydrocarbon metabolism. Long-chain fatty acyl CoA compounds (palmitoyl CoA, oleoyl CoA, linolenoyl CoA; 50 microM) inhibited hydroxylation of benzo(a)pyrene by isolated microsomes by about 45%; however, long-chain fatty acids did not affect overall rates of hydroxylation of benzo(a)pyrene by the perfused liver at concentrations ranging up to 300 microM. The medium-chain acyl CoA compound, octanoyl CoA, also did not affect benzo(a)pyrene hydroxylation in microsomes or liver. Although fatty acids did not alter rates of hydroxylation, the ratio of free benzo(a)pyrene phenols to glucuronides (F/G ratio) increased about 60% (P less than 0.05) in livers perfused with long-chain fatty acids (palmitate, oleate, linolenate). Inhibition of glucuronidation was not observed with the medium-chain fatty acid, octanoate. Benzo(a)pyrene phenols and glucuronides accumulated linearly in the liver at rates of approximately 40 nmol/g/h. A second action of both long- and medium-chain length fatty acids was to increase rates of release of benzopyrene phenols into the perfusate by 50 to 80%. Fatty acids did not effect release of benzo(a)pyrene phenols and glucuronides into bile. Taken together, these data support the hypothesis that fatty acids displace carcinogenic metabolites of benzo(a)pyrene from binding sites in the liver which enter the circulation and travel to target tissues.

Acyl Coenzyme A↗
PubMed1986

Augmentation of ethanol-induced enhancement of dimethylnitrosamine and diethylnitrosamine metabolism by lowered carbohydrate intake.

Hepatic metabolism in vitro of dimethylnitrosamine (DMN), diethylnitrosamine (DEN), 3,4-benzopyrene (BP) and 7,12-dimethylbenz[a]anthracene (DMBA) was assayed using the liver of rats maintained for 3 weeks on liquid diets containing three levels of carbohydrate (CHO) with or without supplementation of ethanol (5 g/100 ml). Ethanol consumption increased the metabolism of DMN and DEN to different degrees depending on the diet consumed simultaneously. Lowered CHO intake, which by itself increased the metabolism, dose-dependently augmented the increase due to ethanol: the lower the CHO intake, the more remarkable was the enhancement caused by ethanol. Ethanol increased microsomal cytochrome P-450 content only when combined with low-CHO diets. It was confirmed by a Salmonella mutagenicity test that the enhancement of DMN and DEN metabolism was accompanied by increased capacity of the liver to activate these nitrosamines to mutagens. On the other hand, neither lowered CHO intake, nor ethanol consumption, nor their combination affected the metabolism of BP and DMBA. Ethanol combined with a diet deficient in CHO even suppressed the metabolism of BP.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1987

Proteolytic enzymes as new tumor markers in chemical carcinogenesis of intestinal tumors.

Because the role of proteolytic enzymes in carcinogenesis is not yet well understood, we studied two arylamidases cleaving Boc-(Ala)2-p-nitroanilide and Bz-Lys-p-nitroanilide in the sera of rats during azoxymethane (AOM)-induced development of bowel carcinomas. Both proteolytic activities exhibited similar patterns: During administration of the carcinogen they increased up to 2.1-fold (Boc-[Ala]2-Nan) and 1.7-fold (Bz-Lys-Nan) the activity of the control group (P less than 0.05). Subsequently they decreased, passing the normal range between weeks 16 and 20 after the first AOM treatment and then diminishing continuously with increasing manifestation of tumors. At week 24 when the last animals were sacrificed enzyme activities were only 36.5% and 43.7% of the controls (P less than 0.05). The early increase may be related to direct effects of the carcinogen. The decrease of serum activity in the further course, however, seems to be a typical event of invasive tumor growth, because a similar loss of activity was also observed in rats with benzopyrene sarcomas. We conclude that both arylamidases may become useful as nonspecific tumor markers.

Aminopeptidases↗
PubMedDate not supplied

Menu software for the processing of spectrofluorometry analysis.

Menu software is presented for the computer-assisted spectrofluorometric analysis of the 3,4-benzopyrene contents of different samples, determined by a method implying the addition of fluorescent substances in the presence of other fluorochromes. A system consisting of an SPF-500 spectrofluorometer interfaced to a Felix-M18 microcomputer was used for this purpose. The advantages of the computer-assisted processing of spectrofluorometric analyses are discussed.

Benzo(a)pyrene↗
PubMed1986

Cytochrome P-450 isoenzyme content and monooxygenase activities in rat liver: effect of ontogenesis and pretreatment by phenobarbital and 3-methylcholanthrene.

The overall cytochrome P-450 content and the immunochemically determined concentrations of constitutive isoenzymes UT-A and UT-I and isoenzymes induced by phenobarbital (PB-B), pregnenolone 16 alpha-carbonitrile (PCN-E), beta-naphthoflavone (BNF-B) and isosafrole (ISF-G) were investigated in liver microsomes from developing rats and tentatively correlated with mono-oxygenase activities. In fetuses of untreated rat, although the cytochrome P-450 was easily quantified spectrally, none of the isoenzymes tested could be immunochemically detected. After birth, each isoenzyme develops in untreated animals with its own pattern of evolution. Mono-oxygenase activities exhibited different developmental pictures. Benzphetamine-N-demethylase and lauric acid 11-hydroxylase activities progressively increased up to adult values, aniline hydroxylase activity was maximal in 15-day-old animals and benzopyrene hydroxylase and lauric acid 12-hydroxylation were increased after birth until 15 days of age in both males and females and underwent a second increase in males. Pretreatment with phenobarbital resulted in the precocious onset of PB-B in fetal and neonatal rat liver accompanied by an increase in classically associated monooxygenase activities. The PCN-E concentration was enhanced by phenobarbital pretreatment only at 15 days and in older animals. BNF-B and benzo(a)pyrene hydroxylase activity were significantly increased by 3-methylcholanthrene whatever the age considered, whereas this inductive effect upon ISF-G concentration became effective only after 2 weeks of age. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis, UT-A was faint in early neonates and intensified at 15 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Aniline Compounds↗
PubMed1985

A simple technique for cell surface radioactive labeling of human and animal neoplastic cells: reductive methylation with formaldehyde and tritiated borohydride.

Avian sarcoma virus-, or 3,4-benzopyrene-transformed cultured rat cells and human leukemia or lymphoblastoid cell lines were radiolabeled by reductive methylation with formaldehyde and tritiated sodium borohydride--an application of a known technique for radiolabeling of soluble proteins. Optimal conditions for tritium incorporation into cell proteins with the aid of this technique were ascertained. Analysis of cell proteins tritium radiolabeled with the aid of this technique by acrylamide electrophoresis or by two-dimensional electrophoretic analysis allowed to disclose typical transformation-associated alterations in oncovirus-, or chemical carcinogen-transformed cells, as well as cell type-associated protein patterns in examined lymphoid cell lines. An individual protein (class II MHC antigen) radiolabeled by this technique has been identified as bimolecular complex p30,35 by immunoprecipitation with a monoclonal antibody recognizing this antigen; electrophoretic properties of immunoprecipitated antigen were identical to those observed after immunoprecipitation of the same antigen radiolabeled by sodium periodate/tritiated borohydride glycoprotein radiolabeling.

Animals↗
PubMed1978

No neoplastic alteration of metabolically competent rat liver cells in vitro by chemical carcinogens: 3-methylcholanthrene, dimethylnitrosamine and Natulan.

Epithelial rat liver cell line RL-19 was checked for aryl hydrocarbon hydroxylase and dimethylnitrosamine demethylase activity. Aryl hydrocarbon hydroxylase activity was found at the rate of about 14.5 pmoles 3-hydroxy-benzopyrene per min per mg protein. This activity was not inducible by 3-methylcholanthrene or by phenobarbital and was independent of the subculture level. From the 45th up to the 59th subculture the mean demethylase activity was about 1.08 nmoles HCHO per min per mg protein, but was decreased to 0.64 nmoles HCHO per min per mg protein at the 131st subculture. RL-19 cells were treated with 3-methylcholanthrene (0.5-1.0 microgram/ml), dimethylnitrosamine (100-400 micrograms/ml), or Natulan (50 micrograms/ml), respectively, for 7 to 10 days. During a 6 months subsequent cultivation no neoplastic changes were observed as revealed by morphological investigation, soft agar assay, and transplantation. It is suggested that metabolic competence for carcinogen activation is only one prerequisite for neoplastic alteration in vitro, and that RL-19 cells are refractory to the action of carcinogens in spite of their metabolic capacity.

Animals↗