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E C Miller

Publications and source records attributed to E C Miller.

At least 37 records · Page 2Linked to original sources
PubMed1987

Structure-activity studies of the hepatocarcinogenicities of alkenylbenzene derivatives related to estragole and safrole on administration to preweanling male C57BL/6J x C3H/HeJ F1 mice.

Further information on the structure-activity relationships among the synthetic and naturally occurring alkenylbenzene derivatives was obtained by examining their hepatocarcinogenicities for mice following administration of one or a few doses prior to weaning. Under these conditions preweanling male C3H/HeJ mice were more susceptible than male C57BL/6J mice or females of either strain to liver tumor induction by 1'-hydroxyestragole (1'-hydroxy-1-allyl-4-methoxybenzene) and 1'-hydroxysafrole (1'-hydroxy-1-allyl-3,4-methylenedioxybenzene). Male C57BL/6J X C3H/HeJ F1 mice given a single dose of 1'-hydroxyestragole at 12 days of age developed approximately twice as many hepatomas per liver as did those given the same dose per g of body weight at 1 day of age. The acetylenic compounds 1'-hydroxy-2',3'-dehydroestragole and 1'-hydroxy-2',3'-dehydrosafrole were the most potent derivatives studied; they were 5- and 10-fold more potent (based on the average numbers of hepatomas per liver) than the corresponding allylic benzene derivatives. 1'-Acetoxyestragole and 1'-acetoxysafrole had activities similar to those of their respective 1'-hydroxy derivatives; estragole derivatives were consistently 2- to 3-fold more potent than the related safrole derivatives. 1'-Hydroxyelemicin (1'-hydroxy-1-allyl-3,4,5-trimethoxybenzene), its acetic acid ester 1'-oxoestragole, and 3'-bromo-trans-anethole (3'-bromo-1-trans-propenyl-4-methoxybenzene) each had very weak, but statistically significant, hepatocarcinogenic activity. The propenylic derivatives cis-anethole, trans-isosafrole, 1:1 cis,trans-isosafrole, 3'-hydroxy-trans-anethole, piperine, and trans-cinnamaldehyde showed no hepatocarcinogenic activity at the levels examined. In contrast, the propenylic derivatives cis- and trans-asarone (1-propenyl-2,4,5-trimethoxybenzene) were each active; the hepatocarcinogenicities of the asarones were not inhibited by prior administration of pentachlorophenol, a sulfotransferase inhibitor that abolished the hepatocarcinogenicity of estragole under the same conditions. Furthermore, precocene II (6,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran), a cyclic propenylic plant metabolite and asarone analogue, showed strong hepatocarcinogenic activity similar to that of 1'-hydroxy-2',3'-dehydroestragole and 1'-hydroxy-2',3'-dehydrosafrole; precocene I (the 7-methoxy analogue of precocene II) was less active than precocene II but more active than cis-asarone.

Age Factors↗
PubMed1987

Hepatic DNA and RNA adduct formation from the carcinogen 7-hydroxymethyl-12-methylbenz[a]anthracene and its electrophilic sulfuric acid ester metabolite in preweanling rats and mice.

DNA and RNA adducts that were chromatographically identical to those formed in vitro on reaction of 7-sulfooxymethyl-12-methyl-benz[a]anthracene with guanine and adenine nucleosides were formed in the livers of rats and mice given i.p. injections of 7-hydroxymethyl- or 7-sulfooxymethyl-12-methyl-benz[a]anthracene. Considerably higher levels of these hepatic adducts were obtained from the latter short-lived electrophilic ester than from the hydroxymethyl compound. These observations are consistent with the finding of rat liver cytosolic sulfotransferase activity for 7-hydroxymethyl-12-methylbenz[a]anthracene (Watabe et al., Science 215, 403, 1982). Formation of these hepatic adducts from 7-hydroxymethyl-12-methylbenz[a]anthracene was inhibited by prior administration to rats of dehydroepiandrosterone, an inhibitor of the sulfotransferase activity for this hydroxymethyl hydrocarbon.

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

Initiation of hepatocarcinogenesis in infant male B6C3F1 mice by N-hydroxy-2-aminofluorene or N-hydroxy-2-acetylaminofluorene depends primarily on metabolism to N-sulfooxy-2-aminofluorene and formation of DNA-(deoxyguanosin-8-yl)-2-aminofluorene adducts.

Previous work from this laboratory provided strong evidence that N-sulfooxy-2-aminofluorene is the major ultimate electrophilic and carcinogenic metabolite of N-hydroxy-2-acetylaminofluorene (N-hydroxy-AAF) in the livers of infant male B6C3F1 (C57BL/6J X C3H/HeJ F1) mice. Over 90% of the hepatic DNA adducts in these mice consisted of N-(deoxyguanosin-8-yl)-2-aminofluorene [N-(dGuo-8-yl)-AF] and less than 10% were deoxyguanosinyl adducts containing 2-acetylaminofluorene (AAF) residues. In the present study hepatic DNA adduct formation and tumor initiation by N-hydroxy-2-aminofluorene (N-hydroxy-AF) were examined in these mice. N-(dGuo-8-yl)-AF was the only adduct detected in the hepatic DNA; the level at 9 h after a single i.p. dose of 0.04 or 0.06 mumol/g body wt of [3H]N-hydroxy-AF was 1.0 or 1.7 pmol/mg DNA. Pretreatment with a single i.p. dose (0.04 mumol/g body wt) of the sulfotransferase inhibitor pentachlorophenol (PCP) decreased the DNA adduct level by greater than 80%. Similar levels of this adduct were found by 32P-postlabeling analysis of DNA from mice treated with unlabeled N-hydroxy-AF. The liver DNA of infant male brachymorphic B6C3F2 mice [deficient in 3'-phosphoadenosine-5'-phosphosulfate (PAPS)] contained only 0.3 pmol/mg DNA of N-(dGuo-8-yl)-AF after an i.p. dose of 0.06 mumol of N-hydroxy-AF/g body wt, while their phenotypically normal (PAPS-sufficient) male littermates had 1.9 pmol/mg DNA. A single i.p. dose of 0, 0.015, 0.03, 0.06 or 0.12 mumol/g body wt of N-hydroxy-AF in infant male B6C3F1 mice induced by 10 months an average of 0.2, 2.5, 7, 11 or 14 hepatomas/mouse. Pretreatment with PCP reduced the liver tumor multiplicity at each dose level by greater than 80%. Essentially the same average tumor multiplicities and inhibitions of tumor formation by PCP pretreatment were obtained following injections of N-hydroxy-AF or N-hydroxy-AAF at the three lower dose levels. Collectively these data strongly indicated that N-sulfooxy-2-aminofluorene is the major ultimate electrophilic and carcinogenic metabolite of N-hydroxy-AF in the livers of infant male B6C3F1 mice. Furthermore, since only N-(dGuo-8-yl)-AF adducts were found in the hepatic DNA these lesions appear to be critical in the initiation of hepatocarcinogenesis in these mice by N-hydroxy-AF.

2-Acetylaminofluorene↗
PubMed1987

Inhibition by pentachlorophenol of the initiating and promoting activities of 1'-hydroxysafrole for the formation of enzyme-altered foci and tumors in rat liver.

The hepatocarcinogen 1'-hydroxysafrole (HOS) exhibited weak initiating activity and strong promoting activity for the induction of enzyme-altered foci and tumors in rat liver. Thus, administration of a single dose of HOS to rats 18 h after a 70% hepatectomy, followed by administration of phenobarbital (PB) in the diet for 6 months, induced a low, but statistically significant, number of foci of enzyme-altered cells. This treatment did not result in gross liver tumors, even when the PB treatment was continued for 16 months. Large numbers of enzyme-altered foci developed when HOS was administered in the diet at levels of 0.05-0.25% to rats previously administered a single dose of N,N-diethylnitrosamine (DEN) 24 h after a 70% hepatectomy. Similarly, rats given a single dose of DEN 24 h after a partial hepatectomy and then fed 0.10 or 0.25% of HOS in the diet for 10 months developed a high incidence of hepatocellular carcinomas. In the absence of pretreatment with DEN, dietary administration for at least 4 months of 0.10 or 0.25% of HOS induced significant numbers of enzyme-altered foci; these data and liver tumor induction by continuous feeding of HOS, in the absence of pretreatment with DEN, provide additional evidence for an initiating, as well as a promoting, activity of HOS in rat liver. Concurrent administration of the hepatic sulfotransferase inhibitor pentachlorophenol with HOS in each of the above assays almost completely inhibited the initiating and promoting activities of HOS for the formation of enzyme-altered foci and tumors; these data strongly suggest that both the initiating and promoting activities are mediated by the sulfuric acid ester, 1'-sulfooxysafrole. HOS also exhibited initiating activity in adult mouse liver. Thus, dietary administration of 0.25% of HOS for only 1 month, followed by administration of the hepatic tumor promoter 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene resulted in a high incidence and multiplicity of hepatomas by 10 months. In the absence of the promoter, administration of HOS for only 1 month induced no hepatomas; 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene alone induced only a low incidence. In mice not given the promoter, continuous administration of HOS for 3-6 months was required for hepatoma development by 16 months.

Animals↗
PubMed1986

Carcinogens and mutagens that may occur in foods.

The principal carcinogens and mutagens that have been identified in human foods are reviewed. These agents may occur in foods as naturally occurring components (e.g., metabolites made by plant or fungal cells), components of contaminating plants or microorganisms, food additives (usually unintentional), or products that arise during processing or cooking. In the mixed diets of developed countries the levels of the known carcinogens and mutagens are very low. However, serious contamination of foods by the potent hepatocarcinogen aflatoxin B1 has occurred in some parts of the world; contamination by N-nitroso compounds or their precursors is another important concern. Extrapolation of the data on the carcinogenicity and mutagenicity of chemicals that can occur in foods to an accurate estimation of the potential hazard to human populations is not yet possible.

Animals↗
PubMed1986

Activating mutations of the c-Ha-ras protooncogene in chemically induced hepatomas of the male B6C3 F1 mouse.

Activated c-Ha-ras protooncogenes have recently been identified in the DNA of some spontaneous hepatic tumors found in 2-year-old B6C3 F1 mice. Activation of c-Ha-ras has now been demonstrated in DNA from well-differentiated hepatomas initiated by a single dose of carcinogen given to male B6C3 F1 mice at 12 days of age. DNA from each of 25 hepatomas, induced by N-hydroxy-2-acetylaminofluorene, vinyl carbamate, or 1'-hydroxy-2',3'-dehydroestragole, containing transforming activity in the NIH 3T3 transfection assay. Southern analysis of NIH 3T3 cells transformed by DNA from 24 of these hepatomas revealed amplified and/or rear-ranged restriction fragments homologous to a Ha-ras probe. The other tumor contained an activated Ki-ras gene. Immunoprecipitation and NaDodSO4/PAGE analysis of p21 ras proteins in NIH 3T3 transformants derived from a majority of the hepatomas suggested that the activating mutations were localized in the 61st codon of the c-Ha-ras gene. Creation of a new Xba I restriction site by an AT----TA transversion at the second position of codon 61 was detected in DNA from primary tumors and NIH 3T3 cells transformed by DNA from 6 of 7 vinyl carbamate- and 5 of 10 1'-hydroxy-2',3'-dehydroestragole-induced hepatomas. Selective oligonucleotide hybridization demonstrated a CG----AT transversion at the first position of the 61st codon in NIH 3T3 transformants derived from 7 of 7 N-hydroxy-2-acetylaminofluorene-induced hepatomas. By the same criterion, an AT----GC transition at the second position of codon 61 was the activating mutation in 1 of 7 vinyl carbamate- and 5 of 10 1'-hydroxy-2',3'-dehydroestragole-induced tumors. Thus, c-Ha-ras activation is apparently an early event in B6C3 F1 mouse hepatocarcinogenesis that results directly from reaction of ultimate chemical carcinogens with this gene in vivo.

Animals↗
PubMed1986

Identification and quantitation of hepatic DNA adducts formed in B6C3F1 mice from 1'-hydroxy-2',3'-dehydroestragole: comparison of the adducts detected with the 1'-3H-labelled carcinogen and by 32P-postlabelling.

The identities and levels of DNA adducts formed in mouse liver after administration of the hepatocarcinogen [1'-3H]1'-hydroxy-2',3'-dehydroestragole obtained by analysis of the 3H-containing adducts were compared with those found by 32P-postlabelling analysis. As previously observed the two diastereomers of N2-(dehydroestragol-1'-yl)-deoxyguanosine were the only adducts detected by use of the tritiated carcinogen. Similarly, the unresolved diastereomers of N2-(dehydroestragol-1'-yl)-deoxyguanosine-3',5'-diphosphate were the only adducts detected by the postlabelling procedure. Analysis by 32P-postlabelling of defined mixtures of the normal deoxynucleoside-3'-phosphates and synthetic N2-(dehydroestragol-1'-yl)-deoxyguanosine-3'-phosphate showed that recovery of the labelled adduct was about 60% of that of the normal nucleotides. Likewise, the levels of the adduct in the hepatic DNA from mice treated with 1'-hydroxydehydroestragole, as determined by 32P-postlabelling, were generally 60-80% of those obtained by analysis for the tritiated adducts. Since 1'-oxodehydroestragole-deoxyadenosine adducts, the major products obtained on reaction of 1'-oxodehydroestragole with DNA in vitro, were not detected by 32P-postlabelling in the hepatic DNA from mice treated with 1'-hydroxydehydroestragole, these data provide further evidence that the covalent binding of 1'-hydroxydehydroestragole to liver DNA in vivo does not involve the 1'-oxo derivative.

Animals↗
PubMed1986

Apurinic/apyrimidinic site induction in supercoiled DNA and mutagenesis in Salmonella typhimurium TA100 by 1'-acetoxysafrole and related electrophilic alkenylbenzene derivatives.

The abilities of seven electrophilic alkenylbenzene derivatives related to 1'-acetoxysafrole to induce apurinic/apyrimidinic (AP) sites in supercoiled SV40 DNA were quantitated by gel electrophoresis after neutral thermal hydrolysis of DNA adducts with unstable N-glycosidic bonds and putrescine/Mg2+ ion-enhanced cleavage of the adjacent phosphodiester linkages. A 20-fold range in AP site production was observed for this series of closely related electrophiles. Analysis of SV40 DNA modified with [2',3'-3H]-1'-acetoxysafrole indicated that approximately 14% of the total safrole-DNA adducts generated AP sites under the conditions used. Neutral thermal hydrolysis of the modified DNA released a product with the same h.p.l.c. retention time as N7-(isosafrol-3'-yl)guanine. The mutagenic potencies in Salmonella typhimurium strain TA100 of these seven electrophilic alkenylbenzene derivatives covered a 75-fold range (from 0.1 to 7.7 revertants/nmol). Although the mutagenic activities of these electrophiles generally correlated well with the hepatocarcinogenic activities of the parent 1'- or 3'-hydroxy derivatives on administration to preweanling male mice, the mutagenic and carcinogenic activities did not correlate with the abilities to induce AP sites.

Alkylation↗
PubMed1986

Sulfuric acid esters as major ultimate electrophilic and hepatocarcinogenic metabolites of 4-aminoazobenzene and its N-methyl derivatives in infant male C57BL/6J x C3H/HeJ F1 (B6C3F1) mice.

Liver cytosols from 12-day-old male C57BL/6 X C3H/HeJ F1 (B6C3F1) mice contain 3'-phosphoadenosine-5'-phosphosulfate (PAPS)-dependent sulfotransferase activity for N-hydroxy-4-aminoazobenzene and N-hydroxy-N-methyl-4-aminoazobenzene. No acetyl co-enzyme A-dependent transacetylase activity for these hydroxylamines was detected in the cytosols. Pentachlorophenol (PCP) and 2,6-dichloro-4-nitrophenol were only moderately active inhibitors of the sulfotransferase activity; at a 100-microM concentration each compound inhibited the activity by only 50-80%. A single dose of 0.04 mumol/g body weight of PCP administered to 12-day-old male B6C3F1 mice 45 min prior to a single dose of 0.1 mumol/g body weight of [3H]4-aminoazobenzene ([3H]AB) or [3H]N,N-dimethyl-4-aminoazobenzene ([3H]DAB) inhibited DNA adduct formation by approximately 50%. Under identical conditions, PCP also reduced the average number of hepatomas induced per mouse at 9 months by AB and N-methyl-4-aminoazobenzene (MAB) by 52 and 36%, respectively. PCP strongly inhibited the hepatocarcinogenicity of DAB or AB when this agent was administered in the diet with either dye to female CD-1 mice over a 10- month period. Single doses of 0.15 mumol/g body weight of [3H]AB and [3H]DAB bound to hepatic DNA of 12-day-old brachymorphic B6C3F2 mice, which are deficient in the synthesis of PAPS, at levels 15 and 20%, respectively, of those found in their phenotypically normal litter mates. Under identical conditions, the incidence of hepatomas in brachymorphic mice at 9 months were 11 and 29%, with averages of 0.2 and 0.8 hepatomas/mouse for AB and MAB, respectively. Incidences of 77 and 86%, with averages of 6.6 and 5.4 hepatomas/mouse, respectively, were found in their phenotypically normal litter mates. These data strongly indicate that N-sulfoöxy-AB is a major ultimate electrophilic and hepatocarcinogenic metabolite of AB in mice. Similarly, this ester and N-sulfoöxy-N-methyl-4-aminoazobenzene appear to be critical metabolites for these activities of DAB and MAB.

Acetyltransferases↗
PubMed1985

The activities of 2,2',5,5'-tetrachlorobiphenyl, its 3,4-oxide metabolite, and 2,2',4,4'-tetrachlorobiphenyl in tumor induction and promotion assays.

Sensitive assays for the induction of lung adenomas in A/J mice or skin papillomas in SENCAR mice failed to show activity for either 2,2',5,5'-tetrachlorobiphenyl or 2,2',5,5'-tetrachlorobiphenyl 3,4-oxide. Injections of the 3,4-oxide into preweanling A/J mice caused considerable mortality, whereas the parent hydrocarbon did not. Both 2,2',5,5'- and 2,2',4,4'-tetrachlorobiphenyl showed promoting activity for hepatic gamma-glutamyl transpeptidase-positive foci initiated in rat liver by treatment with diethylnitrosamine. The promoting activity of 2,2',4,4'-tetrachlorobiphenyl was approximately 10-fold greater than that of the 2,2',5,5'-isomer.

Adenoma↗
PubMed1985

N-sulfoöxy-2-aminofluorene is the major ultimate electrophilic and carcinogenic metabolite of N-hydroxy-2-acetylaminofluorene in the livers of infant male C57BL/6J x C3H/HeJ F1 (B6C3F1) mice.

The hepatic DNA of 12-day-old male B6C3F1 (C57BL/6J X C3H/HeJ) mice given an i.p. dose of 0.06 or 0.11 mumol/g body weight of N-hydroxy-[3H]-2-acetylaminofluorene (N-hydroxy-AAF) contained at 9 h approximately 3 or 6 pmol of N-(deoxyguanosin-8-yl)-2-aminofluorene adducts per mg. Together the level of the two acetylated adducts N-(deoxyguanosin-8-yl)-2-acetylaminofluorene and 3-(deoxyguanosin-N2-yl)-2-acetylaminofluorene was less than or equal to 10% of this amount. The same doses of unlabeled carcinogen induced by 10 months a 100% incidence of hepatomas with averages of 10 and 15 hepatomas per mouse, respectively. Injection of 0.04 mumol/g body weight of pentachlorophenol (PCP) 45 min before the dose of N-hydroxy-AAF decreased the number of adducts in the DNA by 90% and the average number of hepatomas per liver by 80-90%. As compared to their normal male littermates, male brachymorphic B6C3F2 mice, which are deficient in hepatic 3'-phosphoadenosine-5'-phosphosulfate (PAPS), treated with N-hydroxy-AAF formed only 25% as many hepatic DNA adducts and developed only 10% as many hepatomas. Hepatic cytosols from 12-day-old B6C3F1 mice contained PAPS-dependent sulfotransferase activity for N-hydroxy-2-aminofluorene (N-hydroxy-AF), a previously unrecognized activity, as well as sulfotransferase activity for N-hydroxy-AAF; both activities were inhibited 60% by 1 microM and greater than or equal to 80% by 10 microM PCP. Cytosolic acetyl coenzyme A-dependent acetyltransferase activity for N-hydroxy-AF, cytosolic N,O-acyltransferase activity for N-hydroxy-AAF, and microsomal deacetylase for N-hydroxy-AAF were not significantly inhibited by PCP under these conditions. The above data strongly indicate that N-sulfoöxy-2-aminofluorene is the major ultimate electrophilic and carcinogenic metabolite of N-hydroxy-AAF in the livers of infant male B6C3F1 mice.

2-Acetylaminofluorene↗
PubMed1985

Major role of hepatic sulfotransferase activity in the metabolic activation, DNA adduct formation, and carcinogenicity of 1'-hydroxy-2',3'-dehydroestragole in infant male C57BL/6J x C3H/HeJ F1 mice.

1'-Hydroxy-2',3'-dehydroestragole is a synthetic acetylenic analogue of 1'-hydroxyestragole, the proximate carcinogenic metabolite of the naturally occurring hepatocarcinogen estragole (1-allyl-4-methoxybenzene). This analogue is considerably more potent than 1'-hydroxyestragole as an hepatocarcinogen in mice. 1'-Acetoxy-2',3'-dehydroestragole reacted readily with deoxyguanosine or deoxyguanosine 5'-monophosphate at neutrality to form two adducts. Adduct I, isolated and characterized after dephosphorylation of the deoxyguanosine 5'-monophosphate product, was a 1:1 mixture of two diastereomers of N2-(2',3'-dehydroestragol-1'-yl)deoxyguanosine. Adduct II was shown to be N-7-(2',3'-dehydroestragol-1'-yl)guanine. The reaction of deoxyadenosine with 1'-acetoxy-2',3'-dehydroestragole at neutrality produced Adducts III and IV. Adduct IV was characterized as N6-(2',3'-dehydroestragol-1'-yl)deoxyadenosine. Administration of [1'-3H]-1'-hydroxy-2',3'-dehydroestragole to male preweanling C57BL/6J x C3H/HeJ F1 (hereafter called B6C3F1) mice resulted in extensive covalent binding to hepatic DNA, RNA, and protein. On hydrolysis of the DNA to nucleosides, a single major adduct accounted for greater than 85% of the DNA-bound 3H. This adduct comigrated with Adduct I in two high performance liquid chromatography systems, had a pH partition profile identical to that of Adduct I, and was present as a mixture of diastereomers in a ratio of 2:1. The identity of the DNA adduct formed in vivo with Adduct I from the reaction of 1'-acetoxydehydroestragole indicated that a reactive ester was a major metabolic precursor in vivo. There was no significant loss of Adduct I from the hepatic DNA by 21 days after a single injection of a carcinogenic dose of 1'-hydroxy-2',3'-dehydroestragole. Adducts II, III, and IV were not detected in significant amounts in the hepatic DNA isolated by a phenol extraction method or by a more rapid hydroxylapatite method. Cytosolic sulfotransferase activity was demonstrated for 1-hydroxy-2',3'-dehydroestragole in mouse liver, and inhibition of this activity by greater than 95% was found on addition of 10 microM pentachlorophenol. The administration of pentachlorophenol (0.04 mumol/g body weight) 45 min prior to a single dose of 1'-hydroxy-2',3'-dehydroestragole (0.04 mumol/g body weight) in 12-day-old male B6C3F1 mice greatly inhibited (87-97%) the covalent binding of 1'-hydroxy-2',3'-dehydroestragole to hepatic macromolecules and the formation of hepatomas at 10 months.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Further characterization of the DNA adducts formed by electrophilic esters of the hepatocarcinogens 1'-hydroxysafrole and 1'-hydroxyestragole in vitro and in mouse liver in vivo, including new adducts at C-8 and N-7 of guanine residues.

The identities of the adducts formed on reaction of the model electrophilic and carcinogenic esters 1'-acetoxysafrole or 1'-acetoxyestragole with deoxyguanosine in vitro and those formed in vivo in the hepatic DNA of 12-day-old male C57BL/6 X C3H/He F1 (hereafter called B6C3F1) mice treated with 1'-hydroxysafrole or 1'-acetoxysafrole were investigated further with more discriminating high-performance liquid chromatography systems than previously used. The adducts formed from the reactions of 1'-acetoxysafrole or 1'-acetoxyestragole are strictly analogous and are distinguished by the prefixes S and E, respectively. Five adducts, including S(E)-II identified by Phillips et al. (Cancer Res., 41: 176-186, 2664-2671, 1981) as N2-(trans-isosafrol-3'-yl)deoxyguanosine and the analogous isoestragole derivative, have been characterized from the reactions with each ester. Adducts S-I and E-I, tentatively identified by Phillips et al. as N2-(safrol-1'-yl)- or N2-(estragol-1'-yl)deoxyguanosine, were each resolved into a pair of diastereomers. The proposed structures for each diastereomer were confirmed by nuclear magnetic resonance and circular dichroism spectroscopy. Two new adducts, i.e., S(E)-V and S(E)-VI, were isolated from each reaction mixture. On the basis of their pKas, their loss of 3H from [8-3H]deoxyguanosine, their retention of 3H from [1',2'-3H]deoxyguanosine, and their nuclear magnetic resonance spectra, Adducts S-V and E-V were characterized as 8-(trans-isosafrol-3'-yl)- and 8-(trans-isoestragol-3'-yl)deoxyguanosine, respectively. Adducts S-VI and E-VI were characterized in a similar manner as 7-(trans-isosafrol-3'-yl)- and 7-(trans-isoestragol-3'-yl)guanine, respectively. Adducts S-III and E-III, minor components described in the earlier studies, were not observed in the present work. High-performance liquid chromatography of hydrolysates of the hepatic DNA of male 12-day-old B6C3F1 mice killed 9 h after a single dose (0.1 mumol/g body weight) of [2',3'-3H]-1'-hydroxysafrole showed that Adducts S-Ia, S-Ib, S-II, S-IV (identified by Phillips et al. as N6-(trans-isosafrol-3'-yl)deoxyadenosine), S-V, and S-VI were present at average levels of 3.5, 7.0, 24.4, 2.9, 1.2, and 3.6 pmol/mg DNA, respectively. Similar levels of these adducts were found in the hepatic DNA after administration of the same dose of [2',3'-3H]-1'-acetoxysafrole under identical conditions.

Animals↗
PubMed1984

Reactions of 2,2',5,5'-tetrachlorobiphenyl 3,4-oxide with methionine, cysteine and glutathione in relation to the formation of methylthio-metabolites of 2,2',5,5'-tetrachlorobiphenyl in the rat and mouse.

Non-enzymatic reactions of the 3,4-oxide of 2,2'5,5'-tetrachlorobiphenyl (TCB) with methionine or N-acetylmethionine in ethanol/neutral buffer at 37 degrees C proceeded very slowly to yield an approx. 1:1 ratio of 3- and 4-methylthio-TCB. Under similar conditions reaction of TCB 3,4-oxide with cysteine proceeded about 100 times more rapidly to yield an approx. 1:1 ratio of 3- and 4-(cystein-S-yl)-TCB as the major products. Cystein-S-yl-3,4-dihydro-hydroxy-TCB(s) was also formed as a minor product from reaction of TCB 3,4-oxide with cysteine in dimethyl sulfoxide/neutral buffer. TCB 3,4-oxide did not react detectably with glutathione in ethanol/neutral buffer at 37 degrees C or 70 degrees C, but reaction in ethanol/pH 8.7 buffer at 37 degrees C proceeded very rapidly to yield about a 1:1 ratio of 3- and 4-(glutathion-S-yl)-TCB and of two glutathion-S-yl-TCB precursors. Glutathion-S-yl-TCB(s) and its precursor(s) were also formed rapidly in a rat liver cytosol-catalyzed reaction of TCB 3,4-oxide with glutathione at neutral pH. The glutathion-S-yl-TCBs readily degraded upon concentration in aqueous alcohol solutions under mild conditions to yield compounds tentatively identified as [N-(5-carboxy-1-pyrrolin-2-yl)-1-glycinocystein-S-yl]-TCBs, (1-glycinocystein-S-yl)-TCBs and 2-oxopyrrolidine-5-carboxylic acid. Rats given a single dose of TCB excreted about 0.07% of the dose in the feces during the first 4 days as 3-methylthio-TCB, 4-methylthio-TCB, 4-methylsulfonyl-TCB, methylthio-hydroxy-TCBs (tentatively identified) and mercapto-TCB(s) (tentatively identified) in about a 1:5:0.1:0.1:0.05 ratio, respectively. Rats given an equimolar dose of TCB 3,4-oxide excreted similar ratios of these fecal metabolites in approx. 10-fold greater quantities. Mice given TCB excreted about 0.1% of the dose in the feces during the first 4 days as 3-methylthio-TCB, 4-methylthio-TCB and 3-methylsulfonyl-TCB in about a 1.5:1:0.05 ratio, respectively. Methylthio-TCBs were not detected (less than 0.0004% of the dose) in the bile of a cannulated rat given a single dose of TCB. About 1.5% of the TCB dose was excreted in the bile as glutathion-S-yl-TCB(s) and its precursor(s). Collectively, the data indicate that TCB 3,4-oxide is a primary metabolic intermediate in the formation of methylthio-metabolites of TCB.

Animals↗
PubMed1984

[Weight-length correlation of newborn infants. A current method for somatic evaluation--standard values].

Over 30,000 deliveries from 1959 to 1980 were evaluated regarding the correlation between birth weight and length of the newborn. The factors influencing the ratios such as sex of the newborn, year of birth and maternal age and parity were investigated. Since 1965, the correlation has no relationship to the year of birth. It was further found that in almost every tenth primigravida the values of the multiparas were not applicable. In primigravidas below age 17 and over age 26 the proportion was 15%. The author therefore proposes that primigravidas are not included into the normal values. About 9,000 neonates of multiparas were used to establish a standard. The correlation is independent of the sex. Male and female newborns can therefore be evaluated by the same standard. A new concept for the evaluation of the somatic state of a newborn was discussed and recommended by the author. This concept uses the usual method which is also used later in life. Evaluation of the body length is correlated to the length of gestation according to length/SSW standards into macrosome , normosome , and microsome and evaluation of the body with a new weight length standard (Figure 10). The advantages are described in several examples. The comparison of the usual evaluation of newborns by weight/SSW with the new concept shows that more differentiated evaluation is possible in about 1/3 of the cases, especially cases with perinatal mortality and RDS. The optimal treatment and observation of the newborn is improved. The scientific evaluation of such problems as fetopathy , premature delivery and dysmature delivery becomes more exact. The danger of misinterpretations and wrong conclusions is diminished.

Birth Weight↗
PubMed1984

4-aminoazobenzene and N,N-dimethyl-4-aminoazobenzene as equipotent hepatic carcinogens in male C57BL/6 X C3H/He F1 mice and characterization of N-(Deoxyguanosin-8-yl)-4-aminoazobenzene as the major persistent hepatic DNA-bound dye in these mice.

In contrast to the well-established requirement for an N-methyl group for efficient hepatic tumor induction by dietary administration of derivatives of 4-aminoazobenzene (AB) to adult rats, we have now observed that AB and its N-methyl and N,N-dimethyl derivatives have high and approximately equal hepatocarcinogenicity when given as a single i.p. dose to male 12-day-old C57BL/6 X C3H/ HeF1 (B6C3F1) mice. The hepatoma multiplicity induced by these dyes was approximately linearly related to the dose from 0.017 to 0.15 mumol/g body weight; at the high dose, an average of 11 hepatomas/mouse was observed at 10 months. Female B6C3F1 mice were resistant to tumor induction under these conditions. AB and its N-methyl derivative also induced the same incidences of hepatomas on administration of a single dose of 0.45 mumol/g body weight to 12-day-old male C3H/He mice (about 15 hepatomas/mouse) or C57BL/6 mice (about 1 hepatoma/mouse). Infant male Fischer rats were much less susceptible; less than 25% of the rats given 4 i.p. injections (0.3 to 0.4 mumol/g of body weight/injection) of N-methyl-4-amino-azobenzene and less than or equal to 5% of those given these doses of N,N-dimethyl-4-aminoazobenzene or AB before 22 days of age developed hepatic carcinomas by 24 months. Reverse-phase high-performance liquid chromatography of enzymatically hydrolyzed hepatic DNA from 12-day-old male B6C3F1 mice or Fischer rats given an i.p. dose (0.08 or 0.3 mumol/g of body weight) of [prime-ring-3H]AB showed a single major adduct which was chromatographically identical to N-( deoxyguanosin -8-yl)-4-aminoazobenzene synthesized by reaction at pH 7 of N-acetoxy-4-aminoazobenzene (formed in situ from N-hydroxy-4-aminoazobenzene and acetic anhydride) with deoxyguanosine. Mouse and rat liver DNA contained 20 and 0.5 pmol, respectively, of this adduct per mg 24 hr after administration of 0.3 mumol of [prime-ring-3H]AB/g of body weight. At 24 hr after administration of N,N-[prime-ring-3H]dimethyl-4-aminoazobenzene to male B6C3F1 mice, N-( deoxyguanosin -8-yl)-4-aminoazobenzene, N-( deoxyguanosin -8-yl)-N-methyl-4-aminoazobenzene, and 3-( deoxyguanosin -N2-yl)-N-methyl-4-aminoazobenzene were present in a ratio of approximately 4:2:1, respectively. Unlike the N-( deoxyguanosin -8-yl)-N-methyl-4-aminoazobenzene adducts, the N-( deoxyguanosin -8-yl)-4-aminoazobenzene adducts were relatively stable in the DNA; the level of the latter adducts decreased about 60% between 24 hr and 21 days.(ABSTRACT TRUNCATED AT 400 WORDS)

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