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PubMedDate not supplied

Effect of dietary fat on selected parameters of toxicity following 1- or 3-month exposure of rats to toluidine isomers.

The aim of the study was to investigate the effect of the dietary fat on selected parameters of toluidines toxicity in rats during subchronic exposure. Three isomers of toluidine (ortho, meta, and para) were administered to rats in the diet for 1 and 3 months at levels 40, 80, 160 mg/kg/day in two kinds of diet containing either 4% or 14% fat. All doses of toluidine isomers produced a 1.5- to 9.8-fold increase in methemoglobin (MetHb) level during both treatment periods. A distinct dose-response relationship was observed, especially for o- and m-toluidine; the effect was generally greater in rats fed high-fat diet. Reduced glutathione level in liver was increased in all treated groups, 1.5- to 5.1-fold, irrespective of the kind of diet. An increase in hepatic lipid peroxidation (thiobarbituric acid reactive substances; TBARS), 1.5- to 4.5-fold, was noticed in the majority of the treated groups. Generally, there was no consistent effect of diet except for p-toluidine where the level of hepatic TBARS was lower in rats fed high-fat diet. Blood urea nitrogen (BUN) level in animals treated with all doses of o- and m-toluidine was 1.3- to 5.0-fold higher in comparison with respective controls. No clear relationship between BUN level and the kind of diet was found. No effect of toluidines on the activity of serum aspartate aminotransferase (AST) and sorbitol dehydrogenase (SDH) were observed. In the majority of groups treated for 30 and 90 days the amount of toluidines in 24-h urine was lower in rats fed high-fat diet. Final body weight gain in rats treated with o- and p-toluidine (80 and 160 mg/kg body weight [b.w.]) was lower as compared to controls. In summary the high-fat diet stimulated methemoglobin formation in rats treated with o- and m-toluidine and cause the decrease in the amount of toluidines in 24-h urine. The high content of fat did not affect consistently the other parameters tested.

Animals↗
PubMed2002

Liver dysfunction among workers handling 5-nitro-o-toluidine.

BACKGROUND: 5-Nitro-o-toluidine is an aromatic nitro amino compound. While other aromatic compounds are known to damage the human liver and are registered as toxic substances, toxicity information concerning 5-nitro-o-toluidine is lacking. AIMS: To investigate the hepatotoxicity of 5-nitro-o-toluidine. PATIENTS AND METHODS: Of 15 workers in the same factory who handled 5-nitro-o-toluidine, three were hospitalised with symptoms of acute liver dysfunction. Suspecting a link between liver dysfunction and working conditions, we correlated workplace factors with clinical findings in all 15 workers. RESULTS: Blood biochemistry tests indicated liver damage in seven of 15 study subjects. Workers who handled 5-nitro-o-toluidine and nitrosyl sulphuric acid often loosened their respiratory protective equipment shortly after 5-nitro-o-toluidine powder had been dispersed into the air of the room. No potential hepatotoxins were present except for 5-nitro-o-toluidine. Six of the affected workers had handled 5-nitro-o-toluidine 12 to 20 times; the seventh worker had handled the powder three times; and the other eight workers without liver dysfunction had handled the material once or twice. No other significant differences in background were evident between the affected and unaffected workers, such as age, sex, or protective measures. Histological findings during recovery from liver damage were similar to those of acute viral hepatitis. None of the 15 subjects has demonstrated liver damage since the factory was closed. CONCLUSIONS: A link between liver dysfunction and 5-nitro-o-toluidine exposure is suggested by greater severity of liver dysfunction associated with more episodes of handling.

Acute Disease↗
PubMed2001

Isolation and characterization of Achromobacter xylosoxidans T7 capable of degrading toluidine isomers.

A bacterial strain capable of utilizing toluidine isomers as its sole source of carbon and energy for growth was isolated from contaminated soil. The isolate was identified as Achromobacter xylosoxidans and was designated strain T7. Strain T7 differs from other toluidine-degrading strains with respect to the use of all three toluidine isomers even as an equimolar mixture. Additionally, strain T7 harbours the ability to use aniline, phenol, and cresols as growth substrates. Utilization of the toluidine isomers was demonstrated by an increase in the bacterial biomass concomitant with a decrease of the respective toluidine concentration in liquid medium with this compound as sole source of carbon and energy. No accumulation of any intermediate was detectable by HPLC-analyses. Results of oxygen uptake experiments with resting cells of strain T7 pre-grown on the respective toluidine and enzymatic investigations in cell-free extracts indicate the metabolization of the toluidines via the respective methylcatechols as intermediates. These compounds are substrates for the meta-cleavage pathway initiated by inducible catechol 2,3-dioxygenase found in toluidine-grown cells of strain T7.

Betaproteobacteria↗
PubMed1993

Biological monitoring for occupational exposures to o-toluidine and aniline.

Epidemiological evidence that occupational exposure to o-toluidine and aniline is associated with an increased risk of bladder cancer led to efforts to identify biomarkers of workplace exposures to these aromatic amines. For the determination of o-toluidine and aniline in worker urine specimens, a method using high performance liquid chromatography (HPLC) followed by electrochemical detection was developed. The limits of detection were 0.6 microgram/l and 1.4 micrograms/l for o-toluidine and aniline, respectively. Recovery of o-toluidine and aniline from spiked urine averaged 86% and 93%, respectively, over a range of 4-100 micrograms/l. Reproducibility in the range 2-100 micrograms/l for analyses of split field samples was 13% (average RSD) for o-toluidine and 16% (average RSD) for aniline. Application of this method to pre- and post-shift samples collected from potentially exposed and unexposed workers indicated elevated concentrations of o-toluidine and aniline in urine from exposed workers. To develop methods for biomarkers of internal dose, o-toluidine binding to the blood proteins hemoglobin and albumin was investigated utilizing in-vivo (rodent) and in-vitro (hemoglobin and albumin) studies. Base-hydrolyzable protein adducts were analyzed by HPLC (fluorescence) and/or GC/electron capture (EC). The methods were compared for sample preparation requirements, selectivity and sensitivity. While the GC/EC method was more sensitive than HPLC, the presence of interfering peaks limited the utility of this approach. Results from these studies suggested that the HPLC method could be useful for determination of o-toluidine exposures in individuals acutely or chronically exposed to high levels.

Aniline Compounds↗
PubMed2001

Structures of mutagens produced by the co-mutagen norharman with o- and m-toluidine isomers.

Norharman, abundantly present in cigarette smoke and cooked foods, is not mutagenic to Salmonella typhimurium strains. However, norharman shows mutagenicity to S. typhimurium TA98 and YG1024 in the presence of S9 mix when coexisting with aromatic amines, including aniline, o- and m-toluidines. We previously reported that the mutagenicity from norharman and aniline in the presence of S9 mix was due to the formation of a mutagenic compound, 9-(4'-aminophenyl)-9H-pyrido[3,4-b]indole (aminophenylnorharman). In the present study, we analyzed the mutagens produced by norharman with o- or m-toluidine in the presence of S9 mix. When norharman and o-toluidine were reacted at 37 degrees C for 20 min, two mutagenic compounds, which were mutagenic with and without S9 mix, respectively, were produced, and these were isolated by HPLC. The former mutagen was deduced to be 9-(4'-amino-3'-methylphenyl)-9H-pyrido[3,4-b]indole (amino-3'-methylphenylnorharman) on the basis of various spectral data, and this new heterocyclic amine was confirmed by its chemical synthesis. The latter mutagen was identified to be the hydroxyamino derivative. Amino-3'-methylphenylnorharman induced 41,000 revertants of TA98, and 698,000 revertants of YG1024 per microg with S9 mix. Formation of the same DNA adducts was observed in YG1024 when amino-3'-methylphenylnorharman or a mixture of norharman plus o-toluidine was incubated with S9 mix. These observations suggest that norharman reacts with o-toluidine in the presence of S9 mix to produce amino-3'-methylphenylnorharman, and this compound is metabolically activated to yield its hydroxyamino derivative. After activation by O-acetyltransferase, it might bind to DNA and exert mutagenicity in S. typhimurium TA98 and YG1024. When norharman and m-toluidine were reacted in the presence of S9 mix, 9-(4'-amino-2'-methylphenyl)-9H-pyrido[3,4-b]indole (amino-2'-methylphenylnorharman) was identified as a mutagen. Thus, the mutagenicity of norharman with m-toluidine may follow a mechanism similar to that with o-toluidine.

Animals↗
PubMed1997

The utility of toluidine blue application as a diagnostic aid in patients previously treated for upper oropharyngeal carcinoma.

OBJECTIVES: This study evaluated the utility (usefulness) of toluidine blue application as an aid to the recognition and diagnosis of clinically evident lesions in a series of patients previously treated for oral cancer and monitored in a cancer center. In addition to increased risk of recurrence of cancer or new second primary lesions, patients who have had previous treatment for oropharyngeal cancer may be more difficult to assess because of tissue changes that occur as a result of previous radiation therapy. STUDY DESIGN: Patients with a history of oral malignancy were assessed by clinical examination followed by application of toluidine blue. Biopsy sites were determined on the basis of unaided visual examination and by the findings on toluidine blue application. Biopsy specimens were reviewed by a pathologist blinded to the clinical findings. RESULTS: Unaided clinical examination identified 78% of carcinoma in situ or invasive malignant lesions compared with toluidine blue application, which identified all (100%) carcinoma in situ or invasive malignant lesions (p = 0.02) and produced no false-negative findings. No differences were found between clinical examination and toluidine application in the detection of dysplastic lesions. CONCLUSION: Toluidine blue retention was seen in all cases of carcinoma in situ and invasive carcinoma, and no false-negative findings were seen with toluidine blue. When used by a trained and experienced clinician in a cancer center, toluidine blue was a valuable visual aid to clinical examination of oral mucosal lesions.

Carcinoma, Squamous Cell↗
PubMed1979

Bioassay of 5-Chloro-o-toluidine for Possible Carcinogenicity (CAS No. 95-79-4).

5-Chloro-o-toluidine, an aromatic amine and dye intermediate, was selected for bioassay by the National Cancer Institute because of the high incidence of bladder cancer observed among dye manufacturing industry workers. A bioassay for the possible carcinogenicity of 5-chloro-o-toluidine was conducted using Fisher 344 rats and B6C3F1 mice. 5-Chloro-o-toluidine was administered in the feed, at either of two concentrations, to groups of 50 male and 50 female animals of each species. Twenty animals of each sex and species were placed on test as controls. The high and low dietary concentrations of 5-chloro-o-toluidine were 5,000 and 2,500 ppm for rats and 4,000 and 2,000 ppm for mice. The compound was administered in the diet for 78 weeks, followed by an observation period of 26 weeks for rats and 13 weeks for mice. There were significant positive associations between the concentrations of 5-chloro-o-toluidine administered and mortality among male and female mice, but not among rats of either sex. Adequate numbers of animals in all groups survived sufficiently long to be at risk from late-developing tumors. Distinct mean body weight depression was apparent when dosed female rats and dosed mice of both sexes were compared to their controls, indicating that the concentrations administered to these animals in this bioassay may have approximated the maximum tolerated concentrations. Since no mean body weight depression, relative to controls, no significantly accelerated mortality, and no signs of toxicity other than fatty metamorphosis of the liver were associated with administration of 5-chloro-o-toluidine to male rats, it is possible that these animals may have been able to tolerate a higher dietary concentration of the compound. There was a significant positive association between the concentration of 5-chloro-o-toluidine administered to male rats and the incidence of adrenal pheochromocytomas in these animals; however, neither of the Fisher comparisons was significant. None of the other statistical tests fortumors at any site in male and female rats indicated a significant positive association between dosage and incidence. In mice of both sexes there were significant positive associations between concentration administered and the incidence of hemangiosarcomas. In addition, the high dose to control Fisher exact comparisons for both sexes were significant. The Cochran-Armitage tests were also significant and positive for the incidences of hepatocellular carcinomas in both sexes of mice. For males and females the high dose to control Fisher exact comparisons were significant, and for females the low dose to control comparison was also significant. Under the conditions of this bioassay, 5-chloro-o-toluidine was carcinogenic to B6C3F1 mice, inducing hemangiosarcomas and hepatocellular carcinomas in both males and females. There was no conclusive evidence of the carcinogenicity of the compound in Fisher 344 rats. Levels of Evidence of Carcinogenicity: Male Rats: Negative Female Rats: Negative Male Mice: Positive Female Mice: Positive Synonyms: 5-chloro-2-methylbenzeneamine; p-chloro-o-aminotoluene; 4-chloro-2-aminotoluene; 2-amino-4-chlorotoluene; o-amino-p-chlorotoluene; 5-chloro-2-methylaniline; 2-methyl-5-chloroaniline; 1-amino-2-methyl-5-chlorobenzene; 1-amino-3-chloro-6-methylbenzene; Fast Red KB Base; Azogene Fast Red KB; Brentamine Fast Red KB Base; Naphthosol Fast Red Base; Naphthanil Red KB Base

Journal Article↗
PubMed2006

Hemoglobin adducts of the human bladder carcinogen o-toluidine after treatment with the local anesthetic prilocaine.

Prilocaine, a widely used local anesthetic, is metabolized to o-toluidine which is classified as human carcinogen. We aimed to assess the impact of prilocaine-treatment on hemoglobin adducts from o-toluidine. Blood samples were obtained before and 24h after receiving prilocaine local anesthesia (Xylonest, 100mg) from 20 head and neck surgery patients and 6 healthy volunteers. Hemoglobin adducts of o-toluidine and 4-aminobiphenyl were determined by gas chromatography/mass spectrometry. Hemoglobin adducts of o-toluidine were significantly increased 24h after 100mg prilocaine-treatment by 21.6+/-12.8ng/g hemoglobin (mean+/-S.D., N=26; P<0.0001). This corresponds to a 6-360-fold increase of o-toluidine adduct levels in 25 patients from 0.54+/-0.95ng/g before treatment to 22.0+/-13.2ng/g 24h after surgery (mean+/-S.D.). Because of an extremely high background level the increase was only 1.6-fold in one patient (40.9ng/g before and 64.4ng/g 24h after prilocaine injection). Current smoking had no influence on background values and on the increase of o-toluidine adducts. No treatment-related differences were seen in mean hemoglobin adduct levels of 4-aminobiphenyl which were significantly higher in smokers, 0.149+/-0.096ng/g (mean+/-S.D., N=8) as compared to nonsmokers 0.036+/-0.035ng/g (mean+/-S.D., N=16; P<0.01). In conclusion, prilocaine anesthesia leads to a massive increase of hemoglobin adducts of the carcinogenic arylamine o-toluidine. This implies a carcinogenic risk which should be taken into account in preventive hazard minimization.

Adolescent↗
PubMed2003

Effect of naturally occurring plant phenolics on the induction of drug metabolizing enzymes by o-toluidine.

Plant phenolics modify the metabolic activation of several carcinogens, including aromatic amines. In this study, we have evaluated the effects of three structurally diversified plant phenolics, protocatechuic acid (PCA), tannic acid (TA) and ellagic acid (EA) on cytochrome p450-dependent enzymes and glutathione S-transferase (GST) activities after oral administration alone or in combination with o-toluidine in rat liver and kidney. Protocatechuic and ellagic acids significantly decreased the activities of ethoxy- (EROD), methoxy- (MROD) and penthoxyresorufin (PROD) dealkylases in liver. In kidney, all phenolics inhibited only the activity of PROD. Enzyme modulation in liver correlated with CA metabolism measured in plasma. Treatment of rats with ellagic acid 1 h before o-toluidine administration diminished the activities of all hepatic alkoxyresorufine dealkylases induced by o-toluidine but increased renal EROD. In contrast to EA, protocatechuic and tannic acids increased the activities of p450-dependent enzymes in liver. All phenolics administered in combination with o-toluidine increased the activity of GST, which was reduced after the treatment with o-toluidine alone. In addition, CA metabolism in plasma resulting from oral treatment with CA was measured. The formation of CA metabolites was reduced by PCA and EA, and the metabolism of CA induced by o-toluidine was depressed by administration of all three phenolics. Our results indicate that plant phenolics, especially EA, may modulate the genotoxic effects of o-toluidine by modifying pathways leading to the formation of its reactive metabolite. Moreover, as the result of CYP1A modification these compounds may affect the metabolism of CA.

Animals↗
PubMed1992

Evaluation of the carcinogenic potential of toluidine blue O in the hamster cheek pouch.

Toluidine blue O has been shown to have clastogenic and mutagenic effects when tested in vitro, suggesting that it may be a carcinogen. Because this might compromise its use for cancer screening, the carcinogenic potential of this dye was investigated in the hamster cheek pouch, an established in vivo carcinogenesis model. Male hamsters were divided into seven groups at age 5 weeks. The right pouches of four groups were painted three times weekly with 2% toluidine blue or the vehicle for toluidine blue, in conjunction with submaximal applications of 9,10-dimethyl-1,2-benzanthracene (DMBA) (groups II and III, 0.5% twice weekly), and groups IV and V, 0.1% three times weekly). The right pouches of two groups received DMBA only (group I, 0.5% three times weekly, the standard maximal amount, and group VI, 0.1% three times weekly). Group VII received toluidine blue (right pouches) and toluidine blue vehicle (left pouches) three times weekly. The extent of carcinomas and other abnormalities (scored histologically) did not differ among groups receiving the same amount of DMBA with and without toluidine blue or vehicle, and no abnormalities were seen in the pouches from group VII. These results demonstrate no effect of toluidine blue as a carcinogen, cocarcinogen, or promoter.

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

Mutagenic potential of toluidine blue evaluated in the Ames test.

Toluidine blue is a vital, metachromatic thiazine dye which is used as an adjunct in clinical examination for the early detection of asymptomatic recurrent or secondary primary carcinoma in individuals who are at high risk for developing oral cancer. Because available data on the mutagenicity of toluidine blue was limited and contradictory, this study was conducted to evaluate the mutagenic potential of toluidine blue in the in vitro Ames Salmonella test. Tester strains TA97a, TA98, TA100 and TA102 were used. Toluidine blue was tested at concentrations of 0.1, 1.0, 10, 50, 100, 250 and 500 micrograms/plate, with and without S9 microsomal activation, and positive and negative controls were included. Results from tests without S9 showed a significant increase (p less than 0.05) in number of revertants in TA102 and in TA97a with 50 and 100 micrograms toluidine blue/plate, respectively. In tests with S9 activation, doses of toluidine blue ranging from 10 to 250 micrograms/plate induced dose-related increases in the number of revertants in all 4 strains. The results of this study indicate that toluidine blue has a mutagenic effect in the Ames test.

Analysis of Variance↗
PubMed1989

Toluidine blue dye as a breast localization marker.

We compared the efficacy of toluidine blue dye vs methylene blue as a visual marker for breast localizations in vitro and in vivo. In phase 1, the dyes were injected into 10 mastectomy specimens and allowed to diffuse for 24-48 hr. In phase 2, the breasts of four premastectomy patients were injected with the dyes and the dyes were allowed to diffuse for 3 3/4, 12, 24, and 47 hr before mastectomy. In phase 3, the breasts of 18 women in whom 20 breast localizations were performed before excisional biopsy were injected with methylene blue or toluidine blue up to 2 hr 10 min before the biopsy. All excised stained breast tissue was evaluated blindly. The amount of pain associated with injections of the dye was recorded. The 22 women in phases 2 and 3 had had mammograms before, and the parenchymal patterns had been classified according to Wolfe. In the patients injected 3 3/4, 12, 24, and 47 hr before mastectomy, more intense staining with less diffusibility was seen with toluidine blue than with methylene blue. In the 20 localization procedures before excisional biopsy, no difference in intensity of staining or radius of diffusion was seen between methylene blue and toluidine blue with maximal diffusion times of 2 hr 10 min. Breast parenchymal pattern did not correlate with stain intensity or diffusibility. The six patients in whom both methylene blue and toluidine blue were injected and the 18 patients in whom either dye was injected felt less discomfort at the time of injection of toluidine blue than of methylene blue. Our results suggest that toluidine blue causes less discomfort and produces a more intense stain with a smaller diffusion radius than methylene blue regardless of breast parenchymal pattern.

Aged↗
PubMed1984

Effect of toluidines on drug metabolizing enzymes in rat liver, kidney and lung.

The effect of pretreatment with o-, m- and p-toluidine on the drug-metabolizing enzymes of liver, kidney and lung in rats were investigated. The activities of microsomal aryl hydrocarbon hydroxylase (AHH), aminopyrine demethylase, NADPH-cytochrome c reductase, epoxide hydrolase, cytosolic glutathione S-transferase as well as the concentrations of cytochrome P-450 and cytochrome b5 were determined. The obtained results showed that o-toluidine increased the activity of AHH in all tested organs; a particularly marked increase was observed in the kidney. The activity of NADPH-cytochrome c reductase and the content of cytochrome b5 were enhanced by o-toluidine only in the liver. m-Toluidine enhanced the glutathione S-transferase activity while the p-isomer increased both the epoxide hydrolase and the glutathione S-transferase activities. p-Toluidine decreased the AHH and aminopyrine demethylase activities and the cytochrome P-450 content. These results may explain in part the previously reported observations on carcinogenic activity of o-toluidine.

Animals↗
PubMed1991

Excess number of bladder cancers in workers exposed to ortho-toluidine and aniline.

A retrospective cohort study of the incidence of bladder cancer was conducted in response to a union request for an evaluation of a possible excess number of cases of bladder cancer at a chemical plant in western New York State. Workers at the plant were exposed to two potential bladder carcinogens--ortho-toluidine (o-toluidine) and aniline. Incidence rates of bladder cancer among workers at the plant were compared with those of the population of New York State (excluding New York City). Among all 1749 workers at the plant, 13 cases of bladder cancer were observed versus 3.61 expected [standardized incidence ratio (SIR) = 3.60; 90% confidence interval (CI) = 2.13-5.73]. Among the 708 workers who worked in areas in which o-toluidine and aniline were used, 7 cases were observed versus 1.08 expected (SIR = 6.48; 90% CI = 3.04-12.2). Among the 288 maintenance, shipping, and janitorial workers thought to have been possibly exposed, 4 cases were observed versus 1.09 expected (SIR = 3.66; 90% CI = 1.25-8.37). Among the remaining 753 workers who were probably not exposed, 2 bladder cancers were observed versus 1.43 expected (SIR = 1.39; 90% CI = 0.25-4.39). Increased risk of bladder cancer was strongly associated with increased duration of employment in the department where o-toluidine and aniline were used (P less than .001). Among workers with 10 or more years of employment in the department, the SIR was 27.2 (90% CI = 11.8-53.7). o-Toluidine is an animal carcinogen more potent than aniline and is known to produce bladder tumors in rats; hence, it is more likely that o-toluidine is responsible for the observed excess number of cases of bladder cancer, although aniline may have played a role.

Adult↗
PubMed2004

Continued epidemic of bladder cancer in workers exposed to ortho-toluidine in a chemical factory.

Ortho-toluidine (o-toluidine), an aromatic amine, is classified by the International Agency for Research on Cancer as a probable human carcinogen. A cohort study published in 1991 reported a 6.5-fold excess incidence of bladder cancer in a chemical plant that used o-toluidine. We report 19 additional cases of bladder cancer among workers in this cohort, yielding a total of 34 cases of bladder cancer in the cohort to date. The number of bladder cancers diagnosed in the recent period has increased. The timing of onset of exposure to o-toluidine of numerous cases of bladder cancer after 1968, and especially 1975, suggests that potentially confounding occupational exposures other than o-toluidine were not responsible for the observed excess bladder cancer. A formal cohort update is strongly indicated. This study further supports the human bladder carcinogenicity of o-toluidine.

Adult↗
PubMed1986

Identification and quantitative determination of aniline and toluidines in human urine.

Aniline and o-, m-, and p-toluidine, which are representative of aromatic amines in cigarette smoke, were identified and quantified in human urine. Smokers excreted 3.1 +/- 2.6 micrograms/24 h of aniline and 6.3 +/- 3.7 micrograms/24 h of o-toluidine (n = 16). Nonsmokers excreted 2.8 +/- 2.5 micrograms/24 h of aniline and 4.1 +/- 3.2 micrograms/24 h of o-toluidine (n = 12). Meta- and p-toluidine were detected in the urine of 2 of 11 smokers and 4 of 9 nonsmokers. The observed intra- and interindividual variations in the amounts of urinary aniline and o-toluidine were relatively large. The results of this study demonstrate for the first time that aniline and toluidines are present in human urine and suggest that sources other than cigarette smoke contribute significantly to their concentrations in urine.

Adult↗
PubMed1996

The role of toluidine blue in assessing margin status after resection of squamous cell carcinomas of the upper aerodigestive tract.

OBJECTIVE: To determine the efficacy of toluidine blue in assessing margin status after removal of squamous cell carcinomas of the upper aerodigestive tract. DESIGN: A prospective study of 50 consecutive patients undergoing surgical resection of squamous cell carcinomas of the upper aerodigestive tract was performed during February 1 to December 1, 1993. After tumor resection, toluidine blue was applied directly to the remaining unresected mucosa. The staining characteristics of the mucosa were then compared with those of frozen-section biopsy specimens of the margins and with the permanent histologic findings of the resected tumor specimen. RESULTS: In three cases, toluidine blue identified a positive margin, which was confirmed on frozen and permanent section. In six cases, false-positive staining was noted, which was most frequently related to traumatic handling of the mucosa during the resection. In no case was a positive margin found on histologic staining that failed to stain with toluidine blue. During routine staining of surrounding unresected mucosa, three cases of a second primary tumor that was not seen on routine evaluation before tumor removal were identified with toluidine blue. In one case, a second T1 oral cavity lesion was found, while in the other cases, separate pharyngeal lesions were identified. CONCLUSION: Based on these findings, it appears that toluidine blue improved the ability to assess margin status at the time of resection, and we advocate its use after resection of tumors to the upper aerodigestive tract.

Carcinoma, Squamous Cell↗
PubMed2000

Differential use of Alcian blue and toluidine blue dyes for the quantification and isolation of anionic glycoconjugates from cell cultures: application to proteoglycans and a high-molecular-weight glycoprotein synthesized by articular chondrocytes.

Alcian blue and toluidine blue dyes form complexes with anionic glycoconjugates (AG) such as proteoglycans (PG) and glycosaminoglycans (GAG). However, the Alcian blue-AG complexes do not readily dissociate, while the toluidine blue-AG complexes do so in salt solutions. This differential dissociation of the dye-AG complexes has been utilized in the analysis and isolation of radiolabeled AG elaborated by articular chondrocyte cultures incubated with the radiolabeled precursors of AG. For the rapid quantification of newly synthesized (35)S-labeled PG, small replicate aliquots of the radiolabeled culture media were applied directly to cellulose acetate strips, stained with Alcian blue and the stained immobilized radiolabeled PG was quantified by liquid scintillation counting. Comparison of anionic glycoconjugates quantified in the culture media employing toluidine blue and Alcian blue staining on cellulose acetate trips gave similar results. Staining on cellulose acetate strips using these two dyes is particularly suited for the simultaneous processing of large numbers of samples, as illustrated by the screening of the effects of biological materials and drugs on AG synthesis, in cultures labeled with [(35)S]-sulfate and [(3)H]-glucosamine. The Alcian blue and toluidine blue precipitation methods yielded similar results for the total AG recovered from the media of TGF-beta-stimulated chondrocytes. Electrophoretic analysis of toluidine blue- and Alcian blue-precipitated AG followed by autoradiography and Alcian blue staining in combination with silver nitrate demonstrated that both dyes yielded similar pattern of bands on gels. However, some AG from Alcian blue precipitate did not enter the gel, suggesting incomplete dissociation of Alcian blue-AG complex. The application of the toluidine blue precipitation method, in combination with enzymatic digestion of the GAG chains of the PGs, is illustrated by the isolation of a non-PG high-molecular-weight AG, as well as the PGs from the media of chondrocyte cultures stimulated by TGF-beta.

Alcian Blue↗