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Biomedical subjects

S R Tannenbaum

Publications and source records attributed to S R Tannenbaum.

At least 91 records · Page 5Linked to original sources
PubMed1993

Urinary markers for exposures to alkylating or nitrosating agents.

Investigation of urinary markers as indices of endogenous nitrosation and of gastric cancer etiology has been a major focus of our work. As part of this effort, studies have been carried out on a Colombian population at high risk for gastric cancer. In this group, nitrosoproline excretion was highly correlated with nitrate excretion in the subpopulation with advanced gastric pathology, but not in control subpopulations with more normal stomachs. Neither urinary 7-methylguanine nor 3-methyladenine was strongly related to gastric pathology or to urinary nitrate or nitrosoproline levels. More recently, as evidence has accumulated concerning the importance of nitric oxide as a cellular messenger, we have begun research toward developing markers for the presence of nitric oxide and for endogenous nitrosation via this compound. Nitric oxide is formed from arginine by activated endothelial cells as a messenger for vasodilation. We have shown that prolonged exercise leads to increased urinary nitrate and that when 15N-arginine is ingested by humans, 15N-nitrate levels increase in 24-hr urine collections. Nitrosohydroxyethylglycine and 3-nitrotyrosine were evaluated as indices for the formation of N-nitrosomorpholine and for the nitration of protein, respectively, under experimental conditions (e.g., immunostimulation) expected to enhance nitric oxide formation. Nitrotyrosine has not proved useful as a biomarker for nitration/nitrosation reactions in immunostimulated rats. Immunostimulation of rats following administration of morpholine led to increases in urinary nitrate and nitrosohydroxyethylglycine. This procedure, however, would not be appropriate for humans due to the toxicity of morpholine and the carcinogenicity of N-nitrosomorpholine.

Adenine↗
PubMed1993

Characterization of various classes of protein adducts.

Analysis of the types of protein adducts formed by chemical carcinogens indicate that adducts may be categorized into various classes according to the nature of the carcinogen as well as the amino acid with which they react. Tryptophan(214) of serum albumin was previously shown to react specifically with N-sulfonyloxy-N-acetyl-4-aminobiphenyl. The same residue is now shown to also react with the sulfate esters of N-hydroxy-N-acetyl-2-aminofluorene and N-hydroxy-N,N'-diacetylbenzidine. Thus, Trp-214 appears to be a binding site for a variety of activated N-aryl hydroxamic acids. Epoxides and diol epoxides derived from polynuclear aromatic hydrocarbons alkylate carboxylic groups in hemoglobin and serum albumin. Because the esters formed are readily hydrolyzed to dihydrodiols and tetrahydrotetrols which can be determined by GC-MS, it is possible to analyze for a wide range of polyaromatic hydrocarbon (PAH) epoxide adducts. With this approach it was shown that human subjects experiencing exposure to ambient levels of environmental PAH do take up and metabolize chrysene and benzo[a]pyrene. Feral, bottom-dwelling fish inhabiting contaminated waters were also examined. Globin adducts containing certain dihydroxy groups such as those arising in anti-diol epoxide adducts were concentrated by boronate affinity chromatography and further analyzed by HPLC with diode-array UV/visible detection. Four compounds were detected that exhibited spectra characteristic of a polynuclear chromophore. Two of these appeared to be isomers. Further instrumental analysis is needed to elucidate the structure of these unknown putative adducts.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

DNA damage and mutation in human cells exposed to nitric oxide in vitro.

Nitric oxide (NO.) is a physiological messenger formed by several cell types. Reaction with O2 forms oxides that nitrosate amines at pH values near 7. We now report experiments in which NO. was added to intact human cells and to aerobic solutions of DNA, RNA, guanine, or adenine. TK6 human lymphoblastoid cells were mutated 15- to 18-fold above background levels at both the HPRT and TK gene loci. Xanthine and hypoxanthine, from deamination of guanine and adenine, respectively, were formed in all cases. NO. induced dose-responsive DNA strand breakage. Yields of xanthine ranged from nearly equal to about 80-fold higher than those of hypoxanthine. Yields of xanthine and hypoxanthine from nucleic acids were higher than those from free guanine and adenine. This was most pronounced for xanthine; 0.3 nmol/mg was formed from free guanine vs. 550 nmol/mg from calf thymus RNA. Nitric oxide added to TK6 cells produced a 40- to 50-fold increase in hypoxanthine and xanthine in cellular DNA. We believe that these results, plus the expected deaminations of cytosine to uracil and 5-methylcytosine to thymine, account for the mutagenicity of nitric oxide toward bacteria and mammalian cells.

Cell Survival↗
PubMed1992

Monoclonal antibodies and rabbit antisera recognizing 4-aminobiphenyl--DNA adducts and application to immunoaffinity chromatography.

Monoclonal antibodies and rabbit antisera were produced that recognized 4-aminobiphenyl, its major DNA adducts and other metabolites. The antigens used to raise these antibodies were synthesized by coupling the aromatic amine to protein through a diazotization reaction. The goal of this immunization strategy was to induce antibodies that also cross-reacted with most 4-aminobiphenyl-derived metabolites. A total of 20 mice and four rabbits were immunized and every animal produced a strong immune response for 4-aminobiphenyl and its derivatives. Two IgG1 monoclonal antibodies, 3D6 and 2E11, were isolated from two different mouse spleen cell fusions. One of the monoclonal antibodies, 3D6, had a high recognition for the three major 4-aminobiphenyl-DNA adducts: N-(deoxyguanosine-8-yl)-4-aminobiphenyl, N-(deoxyadenosin-8-yl)-4-aminobiphenyl and N-(deoxyguanosine-N2-yl)-4-aminobiphenyl, with affinity constants between 2 and 4 x 10(9) l/mol. In addition, one of the rabbit anti-sera had an affinity constant for the DNA adducts of 2.1 x 10(9) l/mole. Thus, the strategy to use a diazotization coupling reaction was successful at producing high-affinity aminobiphenyl-DNA adduct-specific antibodies. Preparative immunoaffinity resins were made for each monoclonal antibody. These resins quantitatively bound 500 ng each [3H]N-acetyl-aminobiphenyl, [3H]N-aminobiphenyl and [3H]N-(deoxyguanosine-8-yl)-4-aminobiphenyl. Preliminary experiments were performed to test the applicability of the preparative monoclonal antibody immunoaffinity column to isolate [3H]4-aminobiphenyl-derived metabolites in dosed rat and dog urine. About 70% of the radioactivity in rat or dog urine could be bound to the immunoaffinity columns. The combined immunoaffinity column/HPLC analysis of the dog urine led to the identification of a novel urinary metabolite, N-formyl-aminobiphenyl. HPLC analysis of a rat urine sample tentatively found 4-aminobiphenyl, N-acetyl-4-aminobiphenyl and N-formyl-4-aminobiphenyl by co-chromatography, and these compounds accounted for 20, 6.8 and 6.5% of the total radioactivity in the chromatogram respectively. Taken together, these data show that these 4-aminobiphenyl-specific monoclonal antibodies can be used in immunoaffinity columns to isolate metabolites and DNA adducts from biological samples.

Aminobiphenyl Compounds↗
PubMed1991

Measurement of 4-aminobiphenyl-hemoglobin adducts in lung cancer cases and controls.

Hemoglobin adducts of the activated carcinogenic aromatic amine 4-aminobiphenyl have been measured in a case-control study of lung cancer. Data obtained for lung cancer cases are compared to those obtained for controls that consisted of patients with either chronic obstructive pulmonary disease or non-pulmonary cancers. Both simple and multivariate analysis found a positive association of 4-aminobiphenyl-hemoglobin adducts with the quantity of tobacco smoked as determined by either urine cotinine or questionnaire data. No association was found between 4-aminobiphenyl-hemoglobin adducts and cancer diagnosis, and adduct levels were not related to remote tobacco use, i.e., total pack years of smoking. There was no association between the levels of adducts detected and the ability of an individual to metabolize debrisoquine (debrisoquine metabolic phenotype, CYP2D6). Whereas 4-aminobiphenyl-hemoglobin adduct levels reflected recent tobacco smoking, they were not correlated with lung cancer risk.

Aminobiphenyl Compounds↗
PubMed1991

Frequency of urination and its effects on metabolism, pharmacokinetics, blood hemoglobin adduct formation, and liver and urinary bladder DNA adduct levels in beagle dogs given the carcinogen 4-aminobiphenyl.

The human urinary bladder carcinogen, 4-aminobiphenyl (ABP), is known to undergo hepatic metabolism to an N-hydroxy arylamine and its corresponding N-glucuronide. It has been proposed that these metabolites are both transported through the blood via renal filtration to the urinary bladder lumen where acidic pH can facilitate the hydrolysis of the N-glucuronide and enhance the conversion of N-hydroxy-4-aminobiphenyl (N-OH-ABP) to a reactive electrophile that will form covalent adducts with urothelial DNA. Blood ABP-hemoglobin adducts, which have been used to monitor human exposure to ABP, are believed to be formed by reactions within the erythrocyte involving N-OH-ABP that has entered the circulation from the liver or from reabsorption across the urothelium. To test these hypotheses directly, experimental data were obtained from female beagles given [3H]ABP (p.o., i.v., or intraurethrally). [3H]N-OH-ABP (i.v. or intraurethrally), or [3H]N-OH-ABP N-glucuronide (i.v.). Analyses included determinations of total ABP in whole blood and plasma, ABP-hemoglobin adducts in blood erythrocytes, ABP and N-OH-ABP levels (free and N-glucuronide) in urine, urine pH, frequency of urination (controlled by urethral catheter), rates of reabsorption of ABP and N-OH-ABP across the urothelium, and apparent volumes of distribution in the blood/tissue compartment. The major ABP-DNA adduct, N-(guan-8-yl)-4-aminobiphenyl, was also measured in urothelial and liver DNA using a sensitive immunochemical method. An analog/digital hybrid computer was then utilized to construct a multicompartmental pharmacokinetic model for ABP and its metabolites that separates: (a) absorption; (b) hepatic metabolism and distribution in blood and tissues; (c) ABP-hemoglobin adduct formation; (d) hydrolysis and reabsorption in the urinary bladder lumen; and (e) excretion. Using this model, cumulative exposure of the urothelium to free N-OH-ABP was simulated from the experimental data and used to predict ABP-DNA adduct formation in the urothelium. The results indicated that exposure to N-OH-ABP and subsequent ABP-DNA adduct formation are directly dependent on voiding frequency and to a lesser extent on urine pH. This was primarily due to the finding that, after p.o. dosing of ABP to dogs, the major portion of the total N-OH-ABP entering the bladder lumen was free N-OH-ABP (0.7% of the dose), with much lower amounts as the acid-labile N-glucuronide (0.3% of the dose).(ABSTRACT TRUNCATED AT 400 WORDS)

Aminobiphenyl Compounds↗
PubMed1991

4-Aminobiphenyl hemoglobin adducts in fetuses exposed to the tobacco smoke carcinogen in utero.

Maternal-fetal exchange of a potent tobacco-related human carcinogen, 4-aminobiphenyl, was studied in smoking (n = 14) and nonsmoking (n = 38) pregnant women. N-Hydroxy-4-aminobiphenyl, the active metabolite of 4-aminobiphenyl, forms chemical addition products (adducts) with hemoglobin. Levels of 4-aminobiphenyl hemoglobin adducts were measured in maternal-fetal paired blood samples obtained from smoking and nonsmoking women during labor and delivery. Carcinogen-hemoglobin adducts were detected in all maternal and fetal blood samples. Levels of such adducts were significantly higher (P less than .001) in maternal and fetal blood samples from smokers: the mean 4-aminobiphenyl hemoglobin adduct level was 92 +/- 54 pg/g of hemoglobin in blood samples from fetuses of smokers, and 17 +/- 13 pg/g of hemoglobin in blood samples from fetuses of nonsmokers; the mean maternal 4-aminobiphenyl hemoglobin adduct level was 183 +/- 108 pg/g of hemoglobin in smokers, and 22 +/- 8 pg/g of hemoglobin in nonsmokers. Fetal carcinogen-adduct levels were consistently lower than maternal levels: the mean maternal to fetal ratio was 2.4 +/- 1.1 in smokers and 1.9 +/- .98 in nonsmokers. Fetal 4-aminobiphenyl hemoglobin adduct levels were strongly associated (correlation coefficient [r2] = .51, P = .002) with maternal 4-aminobiphenyl hemoglobin adduct levels when paired samples from smoking mothers were analyzed. A measure of third-trimester tobacco smoke exposure based on number of cigarettes smoked per day, amount of each cigarette smoked, and depth of inhalation was associated (r2 = .59, P = .029) with maternal 4-aminobiphenyl levels but not with fetal 4-aminobiphenyl levels. This study demonstrates that a potent tobacco-related carcinogen, 4-aminobiphenyl, or its active metabolite, N-hydroxy-4-aminobiphenyl, crosses the human placenta and binds to fetal hemoglobin in concentrations that are significantly higher in smokers than in nonsmokers.

Aminobiphenyl Compounds↗
PubMed1991

Gas chromatographic-mass spectrometric analysis of diols and tetrols from reactions of polycyclic aromatic hydrocarbon epoxides with hemoglobin.

We have evaluated both electron ionization (EI) and negative-ion chemical ionization (NICI) methods for the analysis of trimethylsilyl derivatives of a series of polycyclic aromatic hydrocarbon (PAH) alcohols including styrene diol, benzo[e]pyrene diol and tetrols, cyclopenta[c,d]pyrene diols, benzo[a]pyrene-4,5-diols, chrysene tetrols, benz[a]anthracene tetrols I and II, and syn- and anti-benzo[a]pyrene tetrols. NICI is the more sensitive method for all compounds except styrene diol. Detection limits are compound-dependent and range from 1 fmol for cyclopenta[c,d]pyrene diol to 1 pmol for benzo[e]pyrene diol. The EI detection limit for styrene diol is 60 fmol. PAH alcohols related to the compounds listed above were observed following hydrolysis of hemoglobin which had been reacted with PAH epoxides in vitro. Benzo[a]pyrene tetrols and a chrysene tetrol were observed following hydrolysis of hemoglobin isolated from human smokers' blood. Hydrolysis of styrene oxide treated hemoglobin in 18O-labeled water revealed at least two mechanisms of ester hydrolysis, including the BAL 1 pathway.

Alcohols↗
PubMed1991

Urinary excretion of nitrate, N-nitrosoproline, 3-methyladenine, and 7-methylguanine in a Colombian population at high risk for stomach cancer.

Urinary excretion levels of nitrate and N-nitrosoproline were determined in 160 individuals in a Colombian population at high risk for gastric cancer. In 156 of these subjects urinary levels of 3-methyladenine and 7-methylguanine were determined. Gastric biopsy specimens were obtained from 118 individuals and were histologically characterized according to pathological criteria into the following groups: normal, superficial gastritis, chronic atrophic gastritis, chronic atrophic gastritis with intestinal metaplasia, and dysplastic. The histological changes were correlated with the four variables listed above. There were no significant differences in the excretion of nitrate, N-nitrosoproline, 3-methyladenine, or 7-methylguanine in subjects with different pathological changes. A statistically significant correlation was present between nitrate and N-nitrosoproline excretion in the total population group (r = 0.297, P = 0.0001). A highly significant correlation (r = 0.56, P = 0.0002) was noted for urinary nitrate and N-nitrosoproline excretion in individuals with intestinal metaplasia and dysplasia. An increase in the urinary excretion of 3-methyladenine and 7-methylguanine was associated with tobacco smoking in the total population group.

Adenine↗
PubMed1991

Inhibition of nitrosamine formation by ascorbic acid.

Nitrosation occurs under a wide variety of conditions by reaction of most types of amines with any of a large number of nitrosating species. Nitrite can be formed in vivo via bacterial reduction of nitrate and by activated macrophages and endothelial cells. The mechanism of nitrite formation by mammalian cells is via enzymatic oxidation of arginine to NO followed by oxidation to N2O3 and N2O4. Nitrosatable amines are found in many foods and some, eg, dimethylamine, are synthesized in the body. Precursors of N-nitroso compounds are thus almost constantly present together under favorable reaction conditions in vivo and there is, consequently, considerable interest concerning possible human health risks arising from endogenous formation of this class of compounds. Among many nitrosation inhibitors, most attention has focused on ascorbic acid, which reacts with many nitrosating agents and which is virtually nontoxic. This presentation discusses the chemistry of ascorbic acid inhibition of nitrosation reactions.

Amines↗
PubMed1991

Endogenous incorporation of nitric oxide from L-arginine into N-nitrosomorpholine stimulated by Escherichia coli lipopolysaccharide in the rat.

The endogenous formation of nitrate in the rat, mouse and human occurs through cellular processes involving the oxidation of the guanido group of arginine. These processes proceed from arginine to nitric oxide with subsequent conversion to electrophilic nitrosating agents capable of forming carcinogenic nitrosamines. We have now demonstrated that endogenous nitrosamine formation can occur via cells stimulated in vivo by bacterial lipopolysaccharide (LPS). The nitrosation of morpholine given to rats by i.p. injection yields N-nitrosomorpholine (NMOR) which is subsequently oxidized in the liver. A major metabolite of NMOR, N-nitroso-(2-hydroxyethyl)glycine, was previously shown by other investigators to be excreted into urine. Treatment of rats with LPS, arginine and morpholine creates a large increase in NMOR urinary metabolites over a 24-h period. This process is not influenced by simultaneous dosage with large amounts of NaNO3. Therefore the endogenous LPS-induced formation of NMOR proceeds directly from nitric oxide prior to incorporation into the nitrate body pool. The proportion of endogenously synthesized nitric oxide incorporated into NMOR is approximately 3 x 10(-6).

Animals↗
PubMed1991

Comparison of urinary nitrate, N-nitrosoproline, 7-methylguanine and 3-methyladenine levels in a human population at risk for gastric cancer.

We have measured the urinary excretion of nitrate, N-nitrosoproline, 3-methyladenine and 7-methylguanine in a human population at high risk for gastric cancer. A strong correlation was observed between nitrate and N-nitrosoproline excretion (p less than 0.00000); statistically significant correlations (p less than 0.05) were also observed for N-nitrosoproline with 3-methyladenine (p = 0.003) and with 7-methylguanine (p = 0.03) and for 7-methyl-guanine with nitrate (p = 0.02), although these correlations were sensitive to outliers. Smokers appeared to excrete slightly higher levels of 3-methyladenine than nonsmokers; no other difference was observed between smokers and nonsmokers or between drinkers and nondrinkers. The correlation between N-nitrosoproline excretion and nitrate excretion supports the hypothesis that elevated endogenous nitrate levels may contribute to elevated endogenous formation of N-nitroso compounds.

Adenine↗
PubMed1990

Carcinogen hemoglobin adducts, urinary mutagenicity, and metabolic phenotype in active and passive cigarette smokers.

In 100 healthy volunteers, we have studied the relationship between the type (air- or flue-cured) and number of cigarettes smoked and different biomarkers relevant to the risk of bladder cancer, including the levels of 4-aminobiphenyl (ABP) hemoglobin adduct (a marker of internal dose), urinary mutagenicity in Salmonella typhimurium TA98, and the N-acetylation phenotype (a marker of susceptibility). ABP is a potent bladder carcinogen that is N-acetylated as an overall detoxification step. Levels of the ABP hemoglobin adduct were higher in smokers of black tobacco (air-cured) than in smokers of blond tobacco (flue-cured), confirming our earlier study. In addition, "slow" acetylators had higher levels of the ABP hemoglobin adduct for the same type and quantity of cigarettes smoked. Urinary mutagenicity was also associated with quantity of cigarettes but not with the acetylation phenotype. Convex dose-response relationships were found between the amount smoked and ABP hemoglobin adduct levels or urinary mutagenicity. In 15 nonsmokers who reported exposure to environmental tobacco smoke, ABP hemoglobin adduct levels, unlike urinary mutagenicity, were found to be an aspecific exposure indicator.

Acetylation↗
PubMed1990

Molecular dosimetry of polycyclic aromatic hydrocarbon epoxides and diol epoxides via hemoglobin adducts.

Ten reactive metabolites of five polycyclic aromatic hydrocarbons and styrene were investigated to determine the generality of ester adduct formation with human hemoglobin in the form of RBC and hydrolysis to the corresponding tetrahydrotetrols or dihydrodiols. No exceptions were noted among the compounds tested, which included the anti-diol epoxides of benzo[a]pyrene (BaP), chrysene, and benz[a]anthracene; the syn-diol epoxide of BaP; a mixture of syn- and anti-diol epoxides of benzo[e]pyrene; and epoxides of styrene, benzo[e]pyrene, BaP, and cyclopenta[c,d]pyrene. A test of the propensity of the simplest benzylic epoxide, styrene oxide, to form esters that hydrolyze via a BAL1 mechanism was performed. Hydrolysis of styrene oxide-adducted hemoglobin in H2(18)O at neutral pH yielded 18O incorporation results that suggest this mechanism of hydrolysis is operant to a minor degree in styrene oxide-hemoglobin ester adducts. A method was developed for the isolation and quantification of the polycyclic aromatic alcohols, which consists of enzymatic proteolysis, immunoaffinity chromatography, and gas chromatography-mass spectrometry or fluorimetry. The method allows for routine analysis of hemoglobin from individual samples as small as 1 ml of whole blood. Analysis of blood from different human populations revealed that hemoglobin adducts of the anti-diol epoxide of BaP dominated the spectrum of adducts formed by the selected metabolites.

Chromatography, Affinity↗
PubMed1990

Acetylation phenotype, carcinogen-hemoglobin adducts, and cigarette smoking.

Levels of 4-aminobiphenyl-hemoglobin adducts in smokers of blonde (flue-cured) and black (air-cured) tobacco have been found to be proportional to bladder cancer risk. In addition, risk of bladder cancer due to exposure to occupational carcinogens is elevated in genetically determined slow acetylators. In this study of normal male volunteers, 4-aminobiphenyl-hemoglobin adducts were found to be related to both the quantity and the type of tobacco smoked, as well as to the acetylator phenotype (independently of smoking habits). The demonstration that both the genetically determined slow acetylator phenotype and tobacco smoking are independently associated with levels of the carcinogen 4-aminobiphenyl in adducted hemoglobin suggests a single mechanism to explain the contribution of genetic susceptibility and environmental exposure in bladder carcinogenesis.

Acetylation↗
PubMed1990

Decline of the hemoglobin adduct of 4-aminobiphenyl during withdrawal from smoking.

The hemoglobin adduct of the human bladder carcinogen 4-aminobiphenyl (4ABP-Hb) declined in the blood of 34 smokers enrolled in a withdrawal program, from a mean of 120 +/- 7 (SE) pg/g of hemoglobin at the start to a mean of 82 +/- 6 pg/g after 3 weeks and a mean of 34 +/- 5 pg/g among the 15 exsmokers who had not resumed smoking after 2 months. Although 4ABP-Hb declined faster than expected under the assumption that the human erythrocyte has a life span of 120 days, it persisted much longer than cotinine. Therefore, 4ABP-Hb may complement the use of cotinine as a marker of exposure to tobacco smoke. The strength of the within-person association of 4ABP-Hb with smoking, coupled with the weakness of the between-person association (correlation coefficient, 0.33), is evidence that between-person variation in modifying factors is substantial. Study of the modifiers of 4ABP-Hb levels may help elucidate the etiology of human susceptibility to aromatic amine-induced bladder cancer.

Adult↗