Effect of Nonsurgical Periodontal Therapy on Some Oxidative Stress Markers in Patients with Chronic Periodontitis: A Biochemical Study

Introduction

Chronic periodontitis is the inflammatory disease of the periodontium; the tissue that surround and support the teeth. The aim of the study was to estimate and compare some biochemical oxidative stress markers in patients with chronic periodontitis and healthy controls and to assess the effect of nonsurgical periodontal therapy on these parameters.

Materials and methods

Eighty-two chronic periodontitis patients and 120 healthy controls were recruited for the study. The periodontal status was evaluated using gingival index (GI), plaque index (PI), papillary bleeding index (PBI) and clinical attachment loss (CAL). The biochemical parameters estimated were total antioxidant capacity (TAOC), antioxidant enzymes RBC-superoxide dismutase (RBC-SOD) and glutathione peroxidase (GPx), vitamin C, malondialdehyde (MDA) and Creactive protein (CRP) were also evaluated. Nonsurgical periodontal therapy (scaling and root planing; SRP) was performed on chronic periodontitis patients and a follow-up was done after 3 months.

Results

The study suggests that oxidative stress is induced in chronic periodontitis, as the levels of CRP, MDA and RBC-SOD were significantly higher (p < 0.001) and those of TAOC, GPx and vitamin C were significantly lower (p < 0.001) compared to healthy controls at baseline. SRP therapy significantly improved the clinical and biochemical oxidative stress markers in periodontitis patients.

Conclusion

Chronic periodontitis patients show higher inflammatory manifestations and oxidative stress. SRP therapy helps in lowering inflammatory burden and improving systemic oxidant: Antioxidant imbalance. The SRP therapy may be a useful support in the control and prevention of various inflammatory diseases associated with periodontitis.

How to cite this article

Aziz AS, Kalekar MG, Benjamin T, Suryakar AN, Prakashan MM, Bijle MNA. Effect of Nonsurgical Periodontal Therapy on Some Oxidative Stress Markers in Patients with Chronic Periodontitis: A Biochemical Study. World J Dent 2013;4(1):17-23.

Effect of methylxanthines (coffee/tea consumers) on oral precancer and oral cancer patients with smoking and smokeless tobacco habits

AIM

To study, whether the consumption of regular tea/coffee (methylxanthines) increases the risk of oral cancer in patients with smoking and smokeless tobacco habits.

MATERIALS AND METHODS

This study was conducted on a total of 90 oral cancer and precancerous patients, from western Maharashtra (India) males in the age group of 20 to 45 years who were with smoking and smokeless tobacco habits; also regular tea/coffee consumers were subjected to biochemical parameters such as aspartate transaminase (AST) and alanine transaminase (ALT) from saliva and serum of patients with oral precancer (submucous fibrosis, leukoplakia) and oral cancer patients and compared with 90-age and sex-matched controls. Individuals consent was taken to measure their biochemical parameters, by using Hafkenscheid method in whole saliva and serum. Statistical analysis of variance (ANOVA) with Tukey's correction for multiple group comparisons was performed using Student t-test.

RESULTS

Results show, that a statistically significant increase in value (p < 0.05) in ALT, AST in both saliva and serum was observed in precancerous and oral cancer patients among the study group as compared to the control group.

CONCLUSION

In the present study, there was increase in the levels of ALT, AST enzymes in both saliva and serum levels in the study group as compared to the control group which was statistically significant (p < 0.05) suggesting that long-term exposure of methylxanthines results in impairment of salivary gland antioxidant system which may affect the anticarcinogenic action of saliva.

CLINICAL SIGNIFICANCE

Oral fluids may be utilized effectively to study the variations in the biochemical constituents of saliva of leukoplakia, submucous fibrosis and oral cancer patients.

Treacher Collins syndrome

Treacher Collins syndrome (TCS) is a rare autosomal dominant disorder of craniofacial development. It is a congenital malformation of first and second branchial arch which may affect the size and shape of the ears, eyelids, cheek bones, and jaws. The extent of facial deformity varies from one affected individual to another. A case of 20-year-old boy having TCS is briefly described in this article.

Identification of gel-separated tumor marker proteins by mass spectrometry

Two-dimensional gel electrophoresis with subsequent analysis by mass spectrometry was applied to study differences in protein expression between benign and malignant solid tumors from human beast, lung and ovary cells. Cells from freshly resected clinical material were lysed and the extracts were subjected to isoelectric focusing with immobilized pH gradients followed by second-dimensional separation on 10-13% sodium dodecyl sulfate (SDS)/polyacrylamide gels. Polypeptides were identified using matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometry after in-gel protein digestion. Some of the upregulated polypeptides in malignant cells are of potential importance as markers of tumor proliferation. Twenty such proteins were identified, ten constituting novel identifications and ten sequence verifications of previously gel-matched proteins. The proteins identified span a wide range of functions, but several cases of protein truncation were found. Truncated forms of cytokeratins 6D and 8, and of cathepsin D were identified. Truncated froms of these over-expressed proteins support the presence of proteolytic processing steps in tumor material. The protein processing and the difference between protein and mRNA abundancies in tumors of different malignancy and origin suggest that studies at the protein level are important for an understanding of tumor phenotypes.

Identification of gel-separated tumor marker proteins by mass spectrometry

Two-dimensional gel electrophoresis with subsequent analysis by mass spectrometry was applied to study differences in protein expression between benign and malignant solid tumors from human beast, lung and ovary cells. Cells from freshly resected clinical material were lysed and the extracts were subjected to isoelectric focusing with immobilized pH gradients followed by second-dimensional separation on 10-13% sodium dodecyl sulfate (SDS)/polyacrylamide gels. Polypeptides were identified using matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometry after in-gel protein digestion. Some of the upregulated polypeptides in malignant cells are of potential importance as markers of tumor proliferation. Twenty such proteins were identified, ten constituting novel identifications and ten sequence verifications of previously gel-matched proteins. The proteins identified span a wide range of functions, but several cases of protein truncation were found. Truncated forms of cytokeratins 6D and 8, and of cathepsin D were identified. Truncated froms of these over-expressed proteins support the presence of proteolytic processing steps in tumor material. The protein processing and the difference between protein and mRNA abundancies in tumors of different malignancy and origin suggest that studies at the protein level are important for an understanding of tumor phenotypes.

Molecular characterization and sequencing of antifreeze proteins from larvae of the beetle Dendroides canadensis

The deduced amino acid sequences of antifreeze proteins (AFPs) from larvae of the beetle Dendroides canadensis were determined from both complementary DNAs (cDNAs) and from peptide sequencing. These consisted of proteins with a 25-residue signal peptide and mature proteins 83 (Dendroides antifreeze protein; DAFP-1) or 84 (DAFP-2) amino acids in length which differed at only two positions. Peptide sequencing yielded sequences which overlapped exactly with those of the deduced cDNA sequences of DAFP-1 and DAFP-2, while the partial sequence of another AFP (DAFP-3) matched 21 of 28 residues. Seven 12- or 13-mer repeating units are present in these antifreeze proteins with a consensus sequence consisting of: Cys-Thr-X3-Ser-X5-X6-Cys-X8-X9-Ala-X11-Thr-X1 3, where X3 and X11 tend toward charged residues, X5 tends toward threonine or serine, X6 toward asparagine or aspartate, X9 toward asparagine or lysine, and X13 toward alanine in the 13-mers. The most interesting feature of these proteins is that throughout the length of the mature antifreeze proteins every sixth residue is a cysteine. These sequences are not similar to any of the known fish AFPs, but they are similar to AFPs from the beetle Tenebrio molitor.

Tumor induction by a transformation-defective polyoma virus mutant blocked in signaling through Shc

Transformation of cells in culture by polyoma virus requires integration of signals downstream of middle T-Shc and middle T-phosphatidylinositol 3-kinase interactions, but the same is not true for induction of tumors in the mouse. Thus, a middle T mutant defective in transformation and blocked in binding Shc is able to induce a broad spectrum of tumors after inoculation into newborn mice. The "tumor profile" induced by the mutant shows enhancement of tumors at some sites and reductions at others but otherwise resembles that induced by the wild-type virus. A nontransforming double-mutant blocked in binding phosphatidylinositol 3-kinase as well as Shc is severely affected but still induces some tumors. These results show that pathways that must cooperate to induce full transformation of cells in vitro can act independently and are to a large extent redundant in tumor induction.

Roles of N-glycans with alpha2,6 as well as alpha2,3 linked sialic acid in infection by polyoma virus

Specific glycosylation inhibitors were used to show that N-glycans, and not O-glycans or glycolipids, constitute the major class of receptors on 3T3 cells for polyoma virus. Sialic acid (SA)-specific lectins were used in attempts to confirm the expected SA linkage on N-linked glycans. A lectin specific for alpha2,6 linked SA, a non-receptor type, was slightly more effective in blocking infection than a lectin specific for alpha2,3 linked SA which corresponds to the known receptor specificity. Possible explanations are suggested for this unexpected result.

Micropreparative immobilized pH gradient two-dimensional electrophoresis in combination with protein microsequencing for the analysis of human liver proteins

Simplified methodology has been developed for the direct N-terminal amino acid microsequencing of human liver and hepatoma derived polypeptides, following micropreparative two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Utilization of immobilized pH gradient (IPG) gel strips in the first dimension permitted protein loading of 0.5-2.0 mg with negligible diminution of polypeptide resolution. Following 2-D separation and electrotransfer to polyvinylidene difluoride (PVDF) membranes nearly 100 well resolved Ponceau S stained polypeptides were readily visualized, from which, 32 adult liver S-9 and 72 HepG2 nuclear cytosolic polypeptides were subjected to N-terminal microsequencing. Twenty normal adult liver and 54 HepG2 polypeptides yielded N-terminal sequence information, of which 17 and 19 polypeptides, respectively, exhibited high sequence homology to previously identified proteins. The initial yields of the proteins sequenced ranged from 2-14 pmols and yielded sequences of 14-26 amino acid residues. Many of the adult liver and HepG2 proteins contained inferred leader sequences since the first sequenced residue was several (20-30) residues from the methionine initiation site predicted by the cDNA of the adult liver. Quantitative comparison of 60 well characterized hepatic proteins between normal adult liver and two nontransformed, Chang and WRL-68, and four human hepatoma derived cell lines, HepG2, Huh-7, FOCUS, and SK-Hep, revealed a high homogeneity of protein expression both qualitatively and quantitatively in both whole cell lysate and purified nuclear preparations. Most notable differences include the previously characterized polypeptides: carbamoyl phosphate synthase, MER5 homologous protein, cytidylate kinase, phosphatidylethanolamine-binding protein and mitochondrial enoyl-CoA hydratase as well as three N-terminally blocked polypeptides: 11 (63 kDa/pI 7.00), 56 (26/6.45) and 59 (22/6.00) all of which were expressed at similar levels in normal adult liver tissue and each of the nontransformed, Chang and WRL-68, cell lines but not expressed or expressed at greatly decreased levels in each of tumor derived liver cell lines. Pyruvate carboxylase, superoxide dismutase, serotransferrin, liver fatty acid binding protein, 1-hydroxyprostaglandin dehydrogenase, NADH dehydrogenase (ubiquinone) as well as three N-terminally blocked polypeptides: 9 (57/6.00), 53 (24/4.90) and 63 (16/4.70) were detected only in whole adult liver tissue and not in any of the cultured cell lines. Two additional polypeptides: U35, (27/6.05) and 58 (22/5.70) yielded N-terminal partial amino acid sequences but were not identified in established protein databases. We have shown that micropreparative IPG 2-D PAGE In combination with protein microsequencing provides a convenient one step procedure to rapidly obtain partial amino acid sequence information for nearly 100 individual polypeptides directly from a single 2-D PAGE gel with numerous applications to a wide variety of biological model systems.

Plasma proteins as early biomarkers of exposure to carcinogenic aromatic amines

Two-dimensional gel electrophoresis (2DG) has been used to study the changes induced in dog plasma polypeptides by the known urinary bladder carcinogens, 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA). Treatment with 3-aminobiphenyl (3-ABP) and 1-naphthylamine (1-NA), both considered to be non-carcinogenic, were used as controls. The purpose of this study was: (1) to determine whether or not changes that occurred in the plasma protein patterns were specific to 4-ABP and/or other related carcinogenic arylamines; (2) to measure the time course in the changes of the major polypeptides during dosing and their resynthesis during a recovery period; and (3) to determine, by microsequencing, the biochemical identity of the affected proteins. The results indicate that only the most potent carcinogen, 4-ABP, had the effect of suppressing the expression of some proteins, while the other aromatic amines caused no discernible change in the 2DG patterns during a 12-week dosing period. The 4-ABP caused dramatic suppression of two sets of proteins. One set of three spots had an apparent molecular weight of 32.5 kDa, and a pI of 5.8-6.0. The major component in this group was identified as the beta-chain of haptoglobin. Expression of this protein decreased markedly during the first 2 weeks of treatment and recovered slowly after dosing stopped. Since haptoglobin functions to bind with free hemoglobin and facilitates its elimination from the blood stream, these results can be rationalized as a consequence of 4-ABP binding to hemoglobin in the erythrocyte, resulting in cell death and hemolysis. The 4-ABP modified hemoglobin then binds to haptoglobin and this tertiary complex is purged from the blood stream, resulting in the disappearance of free haptoglobin. A second set of spots (mol. wt., 65 kDa; pI, 6.5-6.6) disappeared much faster than the haptoglobin, and recovered more quickly. The major protein is about one-fifth the intensity of haptoglobin and appeared to be N-terminally blocked. Internal microsequencing of four fragments obtained from tryptic cleavage of the major spot of this group showed significant similarity to the serum albumin sequence of several species. This spot group is not the major serum albumin spot, however, since the latter is readily identified as the most abundant spot on the plasma map. During the course of this study, several other polypeptides in the 2DG map of dog plasma were identified and are presented here.

Noninterfering synthetic peptides as internal controls for amino acid sequencing of sample unknowns

Noninterfering synthetic peptides have been designed that may be used as internal sequencing standards (ISS-1 and ISS-2) by placing them in an amino acid sequencer with the sample. The peptides are composed of four unnatural amino acids which all yield phenylthiohydantoin derivatives having unique retention times compared with those obtained from the commonly observed natural residues. These internal standards indicate how the entire sequencing system was functioning during the actual analysis of an unknown by providing an initial yield and numerous repetitive yields. Verifying proper operation is extremely important when cycles appear blank due to the presence of modified amino acids or a blocked N-terminus. In addition, the ISS peptides can detect and identify different types of sequencing errors. This sometimes eliminates the need to rerun a sample due to blank cycles caused by mechanical malfunctions which result in failure to cleave the N-terminal residues. ISS-1 or ISS-2 may also be utilized during method development to compare different sample supports and to normalize sequencing data from proteins or peptides that have been treated differently.

The rat liver epithelial (RLE) cell nuclear protein database

The master two-dimensional computer database of rat liver epithelial (RLE) cellular proteins (Wirth et al., Electrophoresis 1991, 12, 931-954) has been expanded to include detailed information concerning 1100 nucleoplasmic (cytosolic) and 850 particulate associated [35S]methionine labeled as well as 215 nucleoplasmic and 269 particulate associated [32P]orthophosphate labeled RLE nuclear polypeptides, respectively. The RLE nuclear protein database developed using the Elsie 5 gel analysis system contains both qualitative and quantitative annotations including polypeptide identification number, protein name (if known), molecular weight and pI information, quantitation and polypeptide spot shape, subcellular location, as well as specific information regarding transformation (chemical and spontaneous) and growth-related characteristics. Microsequencing of polypeptides directly from two-dimensional (2-D) blotted membranes has recently been established in our laboratory and provides a highly efficient and rapid means of polypeptide identification in the absence of specific antibodies. At present the RLE protein database is still in the developmental stage and is continually being updated as additional information is obtained. Nonetheless, it is anticipated that knowledge obtained concerning the identification and characterization of specific transformation and/or growth regulatory proteins in the RLE in vitro cell system will not only have direct application to other rodent and human 2-D protein databases currently under development but will also complement them.

Defect in entry and altered pathogenicity of a polyoma virus mutant blocked in VP2 myristylation

We have examined effects of mutations of the minor capsid proteins VP2 and VP3 of polyoma virus. Infection of cells by mutants blocked in expression of either VP2 or VP3 by alterations of their initiator methionine codons led to the rapid selection of wild-type revertants. This reversion suggests a strong, if not absolute, requirement for both proteins in virus growth. A mutant virus, VP2*, in which alanine was substituted for glycine-2, expressed a nonmyristylated form of VP2 that was incorporated into virions. Studies of VP2* revealed a 15- to 20-fold lower specific infectivity and a delay in growth in both primary and established mouse cells compared to wild-type virus. Analysis of the growth delay indicated a defect in an early step of infection, at or prior to uncoating. Synthesis of viral DNA and VP1 was delayed by about 9 hr in mutant compared to that in wild-type infected cells. No evidence was obtained for an effect on either virus assembly (encapsidation) or stability of virions. Infection of mice by the VP2* mutant virus resulted in attenuated virus replication and tumor induction which were much more severely affected following intranasal inoculation than intraperitoneal inoculation.

Polyoma tumorigenesis in mice: evidence for dominant resistance and dominant susceptibility genes of the host

We have determined the tumor responses of nine inbred mouse strains and of two F1 hybrids following inoculation with polyoma virus. The results showed wide variations in the frequencies of mice developing tumors. Correlation with H-2 haplotype were evident. C3H/BiDa mice of H-2k type were fully susceptible, while C57BL/6 mice of H-2b type were completely resistant. DBA/2 and BALB/c mice, both H-2d, were of low susceptibility. Contributions of the major histocompatibility complex were demonstrated using pairs of H-2 congenic mice. Substitution of H-2k on either a BALB/c or a C57BL/10 background resulted in an increase in the frequencies and kinds of tumors induced. Susceptibilities of BALB and C57BL mice bearing the H-2k haplotype were still well below those of C3H/BiDa mice, however. Crosses of C3H/BiDa with BALB/c or BALB.K (H-2k) produced F1s that were of moderate and full susceptibility, respectively. These results indicate two distinct classes of host genes, one at the H-2 locus where different alleles confer varying degrees of resistance and the other a dominant susceptibility gene(s) carried in C3H/BiDa mice.

Infection by polyomavirus of murine cells deficient in class I major histocompatibility complex expression

Embryonic fibroblasts and kidney epithelial cells from beta 2-microglobulin-deficient mice were as infectible by polyomavirus as cells from normal littermates were, as judged by expression of nuclear viral capsid antigen, development of cytopathic effects, and yields of infectious virus. We conclude that expression of intact class I major histocompatibility complex molecules is not essential for polyomavirus infection.

Direct N-terminal sequence analysis of rat liver plasma membrane glycoproteins separated by two-dimensional polyacrylamide gel electrophoresis

Nine previously uncharacterized membrane glycoproteins from normal rat liver have been analyzed by amino acid sequencing from two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) after transblotting to Immobilon-P membranes. Three of these components show altered levels of expression in liver tumors. A single electroblotted polyacrylamide gel yielded sufficient quantities of these glycoproteins for amino acid sequencing and the N-terminal structure could be determined for four of them. The remaining five glycoproteins of interest were not sequenceable in this manner, presumably because they had blocked N-termini. Prior to electrophoresis, two enrichment methods were applied to the crude liver membrane preparations: affinity chromatography with concanavalin A to isolate the plasma membrane glycoproteins and then fast protein liquid chromatography on Superose 12 to obtain components having a specific range of molecular weights. These materials were next subjected to 2-D PAGE using pH 4-6 carrier ampholytes in the first dimension and 7.5% sodium dodecyl sulfate gels in the second. The proteins were then electroblotted to Immobilon-P membranes and located by staining with Coomassie Brilliant Blue R-250. Our results demonstrate that N-terminal sequencing (gas-phase) can be achieved on polypeptides obtained from approximately 250 micrograms of total glycoproteins applied to a single 2-D gel.

Familial transmission of 16p trisomy in an infant

Based on four reported cases including the present case, 16p trisomic infants have remarkably similar features. These are severe developmental delay, psychomotor retardation, typical facies, and anomalies of extremities.

Effect of microsomal enzyme inducers on the urinary excretion pattern of mutagenic metabolites of the carcinogen 2,4-toluenediamine

2,4-Toluenediamine [(TDA) CAS: 95-80-7] was administered to rats pretreated with the microsomal enzyme inducers phenobarbital (PB), beta-naphthoflavone (beta NF), or 3-methylcholanthrene (MCA). The 24-hour urines of male F344 rats were examined for their mutagenic potency by means of the Salmonella assay, with the Aroclor 1254-pretreated rat liver S-9 fraction as an activating system. No revertants were found with TDA or its urinary metabolites in the absence of the S-9 fraction. In the presence of S-9, the number of revertants increased as the concentration of TDA or its urinary metabolites increased. The urinary metabolites, generated after the microsomal enzyme inducers (PB, beta NF, MCA), had increased mutagenic activity as compared with the controls (saline, corn oil). In the presence of beta-glucuronidase (beta G), increased numbers of TA98 revertants were noted in the urine of rats pretreated with PB, saline, or corn oil. Addition of sulfatase did not alter the number of TA98 revertants. Conversely, beta G treatment of urine from rats pretreated with MCA or beta NF led to a decrease in the number of TA98 revertants as compared to levels in urine without beta G. Addition of known urinary metabolites of TDA, such as 4-acetylamino-2-aminobenzoic acid or 2,4-diacetylaminobenzoic acid, to beta NF-pretreated rat urine had no inhibitory effect on the mutagenicity in the absence of beta G. However, in the presence of beta G, the inhibitory effect was similar to that noted with beta NF-pretreated rat urine. Upon separation of urinary metabolites (beta NF-pretreated rat urine) into free, conjugated, and water-soluble forms, the maximum number of TA98 revertants was associated with the free ethyl acetate-extractable fraction, which accounted for the total mutagenic activity associated with the original volume of urine. Conjugated metabolites showed much less mutagenic activity, and an inhibitory principle was associated with the water-soluble fraction.

Sequential analysis of chemically induced hepatoma development in rats by two dimensional electrophoresis

Using the Solt-Farber hepatocarcinogenesis model, a large population of preneoplastic and neoplastic nodules were induced in male Fischer 344 rats. Total cellular polypeptides from normal liver and individual preneoplastic and neoplastic nodules were analyzed for both qualitative and quantitative changes using computer assisted high resolution two-dimensional electrophoresis. Approximately 800-1000 cytosolic and 1200-1400 membrane associated polypeptides were readily separated and detected using an ultrasensitive silver stain. The polypeptide patterns were remarkably similar for each tissue and only four qualitative polypeptide differences were noted. One cytosolic polypeptide, 6.8/57 (designated pl/Mr X 10(-3), and three membrane associated polypeptides, 6.25/41, 6.75/24, and 6.05/21, were expressed in both preneoplastic and neoplastic nodules but not in normal liver. No qualitative polypeptide differences were detected among the individual preneoplastic or individual neoplastic nodules or between preneoplastic and neoplastic nodules. Numerous quantitative changes in both known markers for hepatocarcinogenesis and in as yet unidentified polypeptides were noted. In particular, the Ya subunit of glutathione S-transferase B, the Yb subunit of glutathione S-transferase A, as well as the three isoelectric point variants of the Yp subunit of glutathione S-transferase P were increased 2-, 4-, and 7-fold, respectively, in preneoplastic and neoplastic nodules. Whereas DT-diaphorase was increased 2-3-fold in hyperplastic nodules as compared to normal liver, no differences in the expression of albumin were noted. Although no differences were observed in the expression of aldehyde dehydrogenase in preneoplastic and neoplastic nodules, polypeptide b (6.9/54) was shifted slightly toward the basic region in normal liver. alpha-Fetoprotein was not detected in either preneoplastic or neoplastic nodules. In addition to these changes in known markers, comparison of 500-800 cytosolic and 750-1000 membrane associated polypeptides showed that roughly 4-10% of the polypeptides were undergoing quantitative changes of at least 4-fold during these stages of hepatocarcinogenesis. Thirty (10 cytosolic and 20 membrane) polypeptides were significantly down-regulated while 22 (7 cytosolic and 15 membrane) polypeptides were up-regulated in both preneoplastic and neoplastic nodules. In all cases the direction and magnitude of change were the same in both preneoplastic and neoplastic nodules with the exception of three polypeptides.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of 2,2'-diaminodiphenyldisulfide, a resin hardener, on rats

Guided by structure-activity relationships among carcinogenic aromatic amines, a sulfur-containing aromatic diamine was designed as a possible noncarcinogenic replacement for the resin hardener 4,4'-methylenebis(2-chloroaniline) (MOCA). However, in small-scale tests in rats the analog diaminodiphenyldisulfide (DDDS) caused necrotic changes in the liver, acanthosis and hyperkeratosis of the forestomach, and atrophy and hyperplasia of the ductal epithelium of the kidney. One case of hepatocellular carcinoma was also noted. Furthermore, DDDS caused alterations in the hepatocellular carcinoma was also noted. Furthermore, DDDS caused alterations in the phospholipid pattern of liver, kidney, and spleen, increasing total phospholipid and cholesterol but decreasing triglyceride levels. However, it was not mutagenic in a Salmonella test system, even in the presence of S9 and microsomal fractions from Aroclor 1254-treated rats.

Mutagenicity of urine from rats after administration of 2,4-diaminoanisole: the effect of microsomal enzyme inducers

Ring 14C-labelled 2,4-diaminoanisole disulfate was administered to rats pretreated with the microsomal inducers phenobarbital (PB), beta-naphthoflavone (BNF), 3-methylcholanthrene (MC) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The 24-h urine from rats pretreated with PB showed a 2-fold increase in revertant rate over the corresponding control as measured by the Ames Salmonella test system. Pretreatment of rats with BNF, MC or TCDD decreased the mutagenicity of urine by about 70% when an activating system was used. However, in the absence of an activating system, the urine from rats induced with BNF, MC or TCDD showed a significant (P < 0.001) degree of mutagenicity compared with urine from controls or urine from phenobarbital-induced rats. Release of conjugates by beta-glucuronidase increased the mutagenicity of urine even in the absence of an activating system, but the number of revertants was almost doubled in the presence of an activating system. The urine from rats treated only with the 4 inducers did not show any mutagenicity. 2,4-Diaminoanisole itself was mutagenic only in the presence of an activating system. alpha-Naphthoflavone (ANF) (0.1 mM) inhibited by 85--90% the in vitro mutagenicity of urine, mediated by Aroclor 1254, MC or TCDD induced rat-liver microsomes. The mutagenicity mediated through PB-induced rat-liver microsomes was, however, inhibited only by 16%. Similarly, 0.1 mM metyrapone (MP) inhibited the mutagenicity of urine by Aroclor 1254, MC or TCDD induced rat-liver microsomes by 13--18%. For the same MP concentration a 50% inhibition of the mutagenicity mediated through PB-induced rat-liver microsomes was observed. The mutagenicity pattern for urine in vitro was shown to be similar with liver S9 from rats induced either with Aroclor 1254 or with MC.

Comparison of the metabolism of 2,4-toluenediamine in rats and mice

The excretion, distribution, and metabolism of 2,4-toluenediamine (TDA) have been compared in rats and mice. The elimination of TDA metabolites into urine was faster and more complete in mice than in rats. However, the feces of rats accounted for a greater percentage of the dose in rats than in mice. The distribution of metabolites in tissues were considerably lower in mice than in rats. The major urinary metabolites observed in the rat were 4-acetylamino-2-aminotoluene, 2,4-diacetylaminotoluene, 4-acetylamino-2-aminobenzoic acid. The major metabolites in the mice were 4-acetylamino-2-aminobenzoic acid, 4-acetylamino-2-aminotoluene and 2,4-diacetylaminobenzoic acid.

N-Formylation of an aromatic amine as a metabolic pathway

1. Feeding 2-aminoanthraquinone (2-AAQ) in the diet to Fischer rats led to nephrotoxicity in females, caused by deposits of crystalline material in the kidney tubules. 2. This material consisted of 2-AAQ, N-acetyl-2-AAQ and N-formyl-2-AAQ. N-Formyl-2-AAQ was also identified in the ether extract of urine of rats fed 2-AAQ. 3. This represents the first case of identification of the N-formyl derivative of a primary aromatic amine as a metabolite in vivo.

Metabolism of the dyestuff intermediate 2,4-diaminoanisole in the rat

1. 2,4-Diamino[ring-U-14C]anisole.2HCl administered intraperitoneally to rats is excreted chiefly via the urine (79 and 85% of the dose in 24 and 48 h, respectively). The isotope in the faeces was 2.1 and 8.9% of the dose at 24 and 48 h. 2. The major metabolic pathway was acetylation of the amine groups(s), resulting in 4-acetylamino-2-aminoanisole and 2,4-diacetylaminoanisole. 3. Oxidate pathways yielded 2,4-diacetylaminophenol (O-demethylation), 5-hydroxy-2,4-diacetylaminoanisole (ring hydroxylation), and 2-methoxy-5-(glycol-amido)acetanilide or its isomer (omega-oxidation). 4. These major metabolites were excreted in the urine both as free and glucuronic acid conjugates.

Tumor antigens induced by nontransforming mutants of polyoma virus

We have studied the tumor (T) antigens induced by wild-type polyoma virus and several nontransforming mutants using immunoprecipitation with antisera from animals bearing polyomya-induced tumors followed by sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis. In a variety of mouse cells, wild-type virus induces a major T antigen species with apparent molecular weight of 100,000 daltons, and four minor T antigen species with apparent molecular weights of 63,000, 56,000, 36,000 and 22,000 daltons. Hr-t mutants, which have an absolute defect in transformation, induce a normal 100,000 dalton T antigen but are altered in the minor T antigen species. Hr-t deletion mutants induce none of the minor T antigen species seen in wild-type virus. In their place, these mutants induce T antigen species with molecular weights in the range of 6,000--9,000 daltons. The size of the very small T antigen products does not correlate in any simple way with the size or location of the deletions in the viral DNA. Point hr-t mutants induce two of the four minor T antigen species; they make apparently normal amounts of the 56,000 dalton product and reduced amounts of the 22,000 dalton product, but none of the 63,000 or 36,000 dalton species. Ts-a mutants, which have a temperature-sensitive defect in the ability to induce stable transformation, and which complement hr-t mutants, induce T antigens with the same mobility as wild-type; however, the 100,000 dalton T antigen of ts-a mutants is thermolabile compared to wild-type. A double mutant virus carrying both a ts-a mutation and a deletion hr-t mutation induces a thermolabile 100,000 dalton product and none of the minor T antigen species. Cell fractionation studies with productively infected cells have been carried out to localize the T antigen species.

Localization of gene functions in polyoma virus DNA

Polyoma virus mutants of four functionally distinct groups have been mapped by the marker rescue technique using restriction enzyme fragments of wild-type viral DNA. Nontransforming host-range mutants map in the proximal part of the early region of the viral genome. The same DNA fragment that restores a normal host range also restores normal transforming ability to these mutants. ts-25D, a temperature-sensitive (ts)-a class mutant, maps in the distal part of the early region. ts-3 and ts-1260 map in the proximal and distal parts of the late region, respectively.

Enzymic N-acetylation of 2,4-toluenediamine by liver cytosols from various species

1. 2,4-Toluenediamine was incubated with liver cytosol from various species, or cytosol from various tissues of the hamster or rabbit, in the presence of [1-14C]acetyl-CoA. N-Acetylation occurred selectively at the p-amino group of 2,4-toluenediamine and to a much lesser extent on the o-amino group. 2. In hamsters and rabbits the highest N-acetyltransferase activity was present in the liver cytosol, followed by kidney intestinal mucosa and lung cytosols. 3. Hamster liver cytosol had the greatest activity followed by liver cytosols from guinea-pig, rabbit, mouse and rat. With human liver cytosol only a trace of an N-acetyl derivative of 2,4-toluenediamine was found while dog liver cytosol showed no activity. 4. N-Acetyltransferase activity was maximal at pH 7-5 in mouse, pH 6-0 in rat and man, and pH 7-0 in rabbit liver cytosols. 5. There was a slight difference in the levels of N-acetyltransferases in males and females; the female mouse had more enzyme activity than the male, but the male rat had more enzyme activity than the female.

Long-term effect of benzene in C57BL/6N mice

Weaning male C57BL/6N mice received repeated subcutaneous injections of benzene in corn oil for 54 weeks. These mice and surviving controls were killed 104 weeks after the first injection. There was no evidence of carcinogenic activity in benzene-injected mice. A high incidence of amyloidosis developed in mice of all treated and untreated groups. Butyinitrosourea, used as a positive control, induced lymphomas or leukemias (in most exposed mice) and intestinal tumors in a few.