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‣ Electroanalytical determination of N-nitrosamines in aqueous solution using a boron-doped diamond electrode

OLIVEIRA, Robson Tadeu Soares de; SALAZAR-BANDA, Giancarlo Richard; MACHADO, Sergio Antonio Spinola; AVACA, Luis Alberto
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
Português
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The electrochemical methods cyclic and square-wave voltammetry were applied to develop an electroanalytical procedure for the determination of N-nitrosamines (N-nitrosopyrrolidine, N-nitrosopiperidine and N-nitrosodiethylamine) in aqueous solutions. Cyclic voltammetry was used to evaluate the electrochemical behaviors of N-nitrosamines on boron-doped diamond electrodes. It was observed an irreversible electrooxidation peak located in approximately 1.8 V (vs. Ag/AgCl) for both N-nitrosamines. The optimal electrochemical response was obtained using the following square-wave voltammetry parameters: f = 250 Hz, E(sw) = 50 mV and E(s) = 2 mV using a Britton-Robinson buffer solution as electrolyte (pH 2). The detection and quantification limits determined for total N-nitrosamines were 6.0 x 10(-8) and 2.0 x 10(-7) mol L(-1), respectively.

‣ Pré-concentração de nitrosaminas a partir de amostras aquosas por extração em fase sólida e cromatografia capilar eletrocinética micelar; Pre-concentration of nitrosamines from aqueous samples by SPE and MEKC

Sanches Filho, Pedro Jose; Zanin, Kelen Daiane; Caramão, Elina Bastos; Garcia, Ronaldo Caramão; Rios, Angel; Valcárcel, Miguel
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
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This paper describes the development of a methodology for solid phase extraction (SPE) and pre-concentration of nitrosamines from aqueous samples using granular activated charcoal as stationary phase. Micelar Electrokinetic Capillary Chromatography (MEKC) was used for the separation and identification of the nitrosamines in the extracts. Using a sample with 50 µg L-1 of each nitrosamines standards (dimethylnitrosamine, DMN; diethylnitrosamine, DEN; N-nitrosopyrrolidine, NPYR; N-nitrosopiperidine, NPIP; Nnitrosomorpholine, NMOR), the methodology showed a range of recuperation from 29 to 107% with a linear zone between 10 and 500 µg L-1. The developed methodology can be applicable to the determination of these analytes in different aqueous samples.

‣ Determination of Total Nitrosamines in Vegetables Cultivated Organic and Conventional Using Diamond Electrode

Coffacci, Lidiane; Codognoto, Lucia; Fleuri, Luciana F.; Lima, Giuseppina P.P.; Pedrosa, Valber A.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1122-1127
Português
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Vegetables were analyzed for total N-nitrosamines (NAs) and the influence of disinfection processes was assessed. Differences in NAs found in cabbage, spinach, and broccoli were determined by square wave voltammetry using a boron-doped diamond electrode. Analysis of samples showed that all samples contained detectable levels of NAs but the results indicated that organic contained less than conventionally grown products. The sum of the total NAs was higher in the cabbage samples, ranging between 2.8-3.1 ppb and lower in broccoli samples at 0.2-1.1 ppb. The method described is simple, rapid, selective, and sensitive. The results suggested that the disinfection process affects the level of NAs, in this manner affecting the level of human exposure to NAs. © 2012 Springer Science+Business Media New York.

‣ Determinação de nitrosaminas volateis em salsichas "hot dog".; Determination of volatile nitromines in hot-dog sausage.

Camila Braga Dutra
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/02/2006 Português
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Nitrito e nitrato são os principais ingredientes usados no processo de cura conferindo aroma e cor avermelhada caracteristicos dos produtos curados como, por exemplo, a salsicha e atuando como antioxidantes e antimicrobianos, impedindo o crescimento de Clostridium botulinum. O efeito tóxico mais relevante da presença de nitrato e nitrito é a formação de nitrosaminas as quais são compostos N-nitroso que podem ser formados da reação de agentes nitrosantes com aminas secundárias ou terciaérias. a maior exposição a estes compostos acontece através dos alimentos, onde o modo de preparo e processamento tem grande influência na quantidade de nitrosaminas presente no alimento, sendo que a formação de nitrosaminas durante o processamento pode ser reduzida por incorporação de inibidores, tais como, ácido ascórbico ou xtocoferol. A nitrosaminas voláteis são as que mais ocorrem em alimentos, e são potentes carcinógenos em animais de laboratório induzindo tumores em vários orgãos. O propósito do presente estudo foi otimizar e validar o método de amostragem "headspace" por microestração em fase sólida (SPME, do inglês Solid Phase Microextraction) usando cromatografia gasosa acoplada a um dectector de quimioluminescência ) TEA...

‣ Desenvolvimento de métodos para determinação de N-nitrosaminas em amostras de xampu por cromatografia líquida acoplada à detecção por arranjo de diodos, eletroquímica e espectrometria de massas; Development of analyrtical methods for determination of N-nitrosamines in shampoo samples by liquid chromatography coupled to diode array, electrochemical and mass spectrometry detecto

Larissa de Souza Canaes
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 21/02/2011 Português
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As N-nitrosaminas (NA) são compostos N-nitrosos, que mostraram ser carcinogênicas para uma grande variedade de animais experimentais. Além disso, elas apresentam atividade teratogênica e mutagênica. As NA foram encontradas, durante as últimas três décadas, em uma variedade de produtos de consumo, incluindo cosméticos e produtos de higiene e suas matérias-primas. As NA mais comumente encontradas em cosméticos são a N-nitrosodietanolamina (NDELA), N-nitrosomorfolina (NMOR) e N-nitrosodimetilamina (NDMA), em concentrações que variam desde mg kg até mg kg. Os objetivos deste trabalho foram a avaliação do comportamento eletroquímico de NA sobre eletrodo de diamante dopado com boro e construção de uma célula amperométrica para ser associada ao cromatógrafo líquido de alta eficiência (HPLC), assim como o desenvolvimento e validação de métodos para a determinação de NA em xampu, usando a cromatografia líquida, associada ao detector eletroquímico desenvolvido, arranjo por fotodiodos e espectrometria de massas. O comportamento eletroquímico das NA foi estudado usando voltametria cíclica e voltametria de onda quadrada; foram avaliados composição, concentração e pH do eletrólito suporte. A separação da NA foi realizada em uma coluna C18 XBridge¿ e uma fase móvel composta de água/acetonitrila e eluição por gradiente. No preparo de amostras foram avaliadas a extração líquido-líquido...

‣ Pré-concentração de nitrosaminas a partir de amostras aquosas por extração em fase sólida e cromatografia capilar eletrocinética micelar

Sanches Filho,Pedro José; Zanin,Kelen Daiane; Caramão,Elina Bastos; Garcia,Ronaldo Caramão; Rios,Angel; Valcárcel,Miguel
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2003 Português
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This paper describes the development of a methodology for solid phase extraction (SPE) and pre-concentration of nitrosamines from aqueous samples using granular activated charcoal as stationary phase. micelar electrokinetic capillary Chromatography (MEKC) was used for the separation and identification of the nitrosamines in the extracts. Using a sample with 50 µg l-1 of each nitrosamines standards (dimethylnitrosamine, DMN; diethylnitrosamine, DEN; N-nitrosopyrrolidine, NPYR; N-nitrosopiperidine, NPIP; N-nitrosomorpholine, NMOR), the methodology showed a range of recuperation from 29 to 107% with a linear zone between 10 and 500 µg l-1. The developed methodology can be applicable to the determination of these analytes in different aqueous samples.

‣ Contaminação de produtos de higiene e cosméticos por n-nitrosaminas

Rath,Susanne; Canaes,Larissa S.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 Português
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N-nitrosamines are carcinogenic compounds that have been found during the last three decades in a variety of consumer products, including cosmetic and personal care products, and their raw materials. These compounds are formed from amine precursors and nitrosating agents present in the formulations. This paper reviews the formation and occurrence of N-nitrosamines in cosmetic products, as well as presents considerations about analytical, toxicological and regulatory aspects.

‣ A search for nitrosamines in East African spirit samples from areas of varying oesophageal cancer frequency

Collis, C. H.; Cook, Paula J.; Foreman, J. K.; Palframan, J. F.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1971 Português
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Following the report of the presence of nitrosamine-like substances in samples of homemade spirit from Zambia, which had been obtained from an area where cancer of the oesophagus is common, samples of distilled alcoholic drinks were collected throughout western Kenya and southern Uganda from areas where the frequency of cancer of the oesophagus varies from very common to very rare. The 44 samples of spirit were screened by polarography and substances giving a similar response to nitrosamines were indicated at levels as high as 21 ppm. Subsequent analysis by gas chromatography for selected individual nitrosamines showed no evidence for the occurrence of methylethylnitrosamine (MEN), diethylnitrosamine (DEN), dipropylnitrosamine (DPN), ethylbutylnitrosamine (EBN), dibutylnitrosamine (DBN), nor of N nitrosopiperidine (N Pipn), but traces of compounds having a similar retention time as dimethylnitrosamine (DMN) were observed. However, subsequent examination by mass spectrometry showed no evidence of dimethylnitrosamine. There was no apparent association between the levels of unknown constituents indicated by polarography and gas chromatography, nor between either of these levels and the frequency of cancer of the oesophagus. The results by gas chromatography and mass spectrometry confirm that polarography is too unspecific to be a useful indicator of nitrosamines.

‣ Nitrosamines as nicotinic receptor ligands

Schuller, Hildegard M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
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Nitrosamines are carcinogens formed in the mammalian organism from amine precursors contained in food, beverages, cosmetics and drugs. The potent carcinogen, NNK, and the weaker carcinogen, NNN, are nitrosamines formed from nicotine. Metabolites of the nitrosamines react with DNA to form adducts responsible for genotoxic effects. We have identified NNK as a high affinity agonist for the alpha7 nicotinic acetylcholine receptor (α7nAChR) whereas NNN bound with high affinity to epibatidine-sensitive nAChRs. Diethylnitrosamine (DEN) bound to both receptors but with lower affinity. High levels of the α7nAChR were expressed in human small cell lung cancer (SCLC) cell lines and in hamster pulmonary neuroendocrine cells (PNECs), which serve as a model for the cell of origin of human SCLC. Exposure of SCLC or PNECs to NNK or nicotine increased expression of the a7nAChR and caused influx of Ca2+, activation of PKC, Raf-1, ERK1/2, and c-myc, resulting in the stimulation of cell proliferation. Signaling via the α7nAChR was enhanced when cells were maintained in an environment of 10–15% CO2 similar to that in the diseased lung. Hamsters with hyperoxia-induced pulmonary fibrosis developed neuroendocrine lung carcinomas similar to human SCLC when treated with NNK...

‣ Five- and Six-Coordinate Adducts of Nitrosamines with Ferric Porphyrins: Structural Models for the Type II Interactions of Nitrosamines with Ferric Cytochrome P450

Xu, Nan; Goodrich, Lauren E.; Lehnert, Nicolai; Powell, Douglas R.; Richter-Addo, George B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 17/05/2010 Português
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Nitrosamines are well known for their toxic and carcinogenic properties. The metabolic activation of nitrosamines occur via interaction with the heme-containing cytochrome P450 enzymes. We report the preparation and structural characterization of a number of nitrosamine adducts of synthetic iron porphyrins. The reactions of the cations [(por)Fe(THF)2]ClO4 (por = TPP, TTP, OEP) with dialkylnitrosamines (R2NNO; R2 = Me2, Et2, (cyclo-CH2)4, (cyclo-CH2)5, (PhCH2)2) in toluene generate the six-coordinate high-spin (S = 5/2) [(por)Fe(ONNR2)2]ClO4 compounds and a five-coordinate intermediate-spin (S = 3/2) [(OEP)Fe(ONNMe2)]ClO4 derivative in 57–72% yields (TPP = 5,10,15,20-tetraphenylporphyrinato dianion, TTP = 5,10,15,20-tetra-p-tolylporphyrinato dianion, OEP = 2,3,7,8,12,13,17,18-octaethylporphyrinato dianion). The N–O and N–N vibrations of the coordinated nitrosamine groups in [(por)Fe(ONNR2)2]ClO4 occur in the 1238–1285 cm−1 range. Three of the six-coordinate [(por)Fe(ONNR2)2]ClO4 compounds and one five-coordinate [(OEP)Fe(ONNMe2)]ClO4 compound have been characterized by single crystal X-ray crystallography. All the nitrosamine ligands in these complexes bind to the ferric centers via a sole η1-O binding mode. No arylnitrosamine adducts were obtained from the reactions of the precursor compounds [(por)Fe(THF)2]ClO4 with three arylnitrosamines (Ph2NNO...

‣ Role of aldehydes in the toxic and mutagenic effects of nitrosamines

Peterson, Lisa A.; Urban, Anna M.; Vu, Choua C.; Cummings, Meredith E.; Brown, Lee C.; Warmka, Janel K.; Li, Li; Wattenberg, Elizabeth V.; Patel, Yesha; Stram, Daniel O.; Pegg, Anthony E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
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α-Hydroxynitrosamine metabolites of nitrosamines decompose to a reactive diazohydroxide and an aldehyde. To test the hypothesis that the aldehydes contribute to the harmful effects of nitrosamines, the toxic and mutagenic activity of three model methylating agents were compared in Chinese hamster ovary cells expressing human O6-alkylguanine DNA alkyltransferase (AGT) or not. N-Nitrosomethylurethane (NMUr), acetoxymethylmethylnitrosamine (AMMN) and 4-(methylnitrosamino)-4-acetoxy-1-(3-pyridyl)-1-butanone (NNK-4-OAc) are all activated by ester hydrolysis to methanediazohydroxide. NMUr does not form an aldehyde whereas AMMN generates formaldehyde and NNK-4-OAc produces 4-oxo-1-(3-pyridyl)-1-butanone (OPB). Since these compounds were likely to alkylate DNA to different extents, the toxic and mutagenic activity of these compounds was normalized to the levels of the most cytotoxic and mutagenic DNA adduct, O6-mG, to assess if the aldehydes contributed to the toxicological properties of these methylating agents. Levels of 7-mG indicated that the differences in cytotoxic and mutagenic effects of these compounds resulted from differences in their ability to methylate DNA. When normalized against the levels of O6-mG, there was no difference between these three compounds in cells that lacked AGT. However...

‣ Novel Study on N-Nitrosamines as Risk Factors of Cardiovascular Diseases

Sheweita, Salah A.; El-Bendery, Heba A.; Mostafa, Mostafa H.
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
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Millions of people are exposed daily to N-nitrosamines from different environmental sources. The present study aims at investigating the role of N-nitrosamines in the alteration of homocysteine, lipid profile, oxidative stress, paraoxonase activity, antioxidant enzymes, and free radicals which are important risk factors for CVD. In addition, biomarkers of cardiovascular diseases such as creatine kinase MB activity (CK-MB) and lactate dehydrogenase (LDH) as well as protein expression of both glutathione peroxidase and glutathione S-transferase π isozyme were assayed after treatment of rats with 0.2 mg/kg body weight of N-nitrosodibutylamine (NDBA), N-nitrosoethylbutylamine (NEBA), N-nitrosobutylpropylamine (NBPA), N-nitrosodiethylamine (NDEA), N-nitrosodimethylamine (NDMA), and N-nitrosodiphenylamine (NDPA) as a daily dose for two weeks. LDL levels, paraoxonase activity, reduced glutathione levels, and glutathione reductase activities were increased, whereas HDL levels decreased after treatment of rats with most of N-nitrosamines compared to control group. Moreover, levels of free radicals and catalase activity increased, whereas protein expression of both glutathione peroxidase and glutathione S-transferase decreased after treatment of rats with some N-nitrosamines. The data showed that most N-nitrosamines increased CK-MB and LDH activities. It is concluded that N-nitrosamines increased levels of free radicals...

‣ Évaluation du risque cancérigène associé à la contamination de l’eau potable de puits municipaux par les nitrates/nitrites dans certaines régions rurales du Québec

Chébékoué, Sandrine Fleur
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
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La spécialisation des techniques agricoles que nous connaissons ces dernières décennies, particulièrement dans les régions rurales, est à l’origine de l’abus de fertilisants. Ces derniers sont actuellement reconnus comme étant les causes principales de la contamination de l’eau souterraine par les nitrates. Suite à leur ingestion via l’eau potable, les nitrates sont transformés en nitrites par la flore buccale. Une fois dans l’estomac les nitrites réagissent avec certaines amines provenant de l’alimentation pour générer des nitrosamines cancérogènes. L’objectif de notre étude était d’estimer quantitativement l’excès de risque de cancer (ER) pour les populations de sept régions rurales du Québec qui consomme l’eau potable provenant de réseaux municipaux alimentés en eau souterraine. Le territoire à l’étude était caractérisé par une agriculture intensive d’élevage. Les médianes (et 95e centiles) régionales des concentrations de nitrates mesurées dans les réseaux de ces régions étaient de : 0,18 (2,74); 0,48 (10,35); 0,15 (1,28); 0,32 (11); 0,05 (0,76); 0,10 (4,69); 0,09 (2,13) mg N-NO3-/l. Nous avons envisagé un scénario de transformation complète des nitrites et de certaines amines (diméthylamine...

‣ NDMA attracting international attention: the latest news on nitrosamines

Newcombe, G.; Morran, J.; Culbert, J.A.
Fonte: Australian Water Association Publicador: Australian Water Association
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
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N-nitrosodimethylamine (NOMA), and nitrosamines in general, are attracting increasing worldwide attention. While Australia has now established a guideline for NOMA, other countries such as New Zealand, the US, Canada and the European Union, are still deciding the most appropriate concentration of this disinfection by-product to allow in drinking water, and whether to include other nitrosamines in any ruling. Such intense interest brings an increase in knowledge, so the authors considered it timely to publish an update on the situation regarding nitrosamines in Australia and overseas. This paper complements similar topic reviews published in 2006 (Nicholson, 2006) and 2009 (Newcombe et al., 2009).; G Newcombe, J Morran, J Culbert

‣ Distribution of Seven N-Nitrosamines in Food

Park, Jong-eun; Seo, Jung-eun; Lee, Jee-yeon; Kwon, Hoonjeong
Fonte: The Korean Society Of Toxicology Publicador: The Korean Society Of Toxicology
Tipo: Artigo de Revista Científica
Publicado em /09/2015 Português
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N-nitrosamines, which are classified as carcinogens by IARC and US EPA, can be easily found in various foods. They are reaction products between nitrogen oxide and secondary amines, but can also be generated during fermentation. Ever since the 1960s, when nitrite, used as a preservative in processed meats, was suspected to generate N-nitrosamines, the usage of the food additive has been debated. However, the benefit of nitrite in food supply could not be ignored and the risk-benefit analysis has become a key issue in the use of the additive. For a risk analysis, an accurate estimation of the hazardous material is necessary; therefore, analytical methods for nitrosamines have continuously evolved from the 1950s. Solid supported liquid-liquid extraction and solid phase extractions have replaced the distillation for the clean-up steps, and tandem mass spectrometry is employed for higher selectivity and sensitivity. In the present study, for a better estimation of N-nitrosamine intake, the total diet study samples were prepared for the N-nitrosamines analysis. In order to obtain the most sensitive results, a partial preparation procedure was developed and modified for different food matrices. Among seven N-nitrosamines (N-nitrosodimethylamine...

‣ Nitrosamines in bacon: a case study of balancing risks.

McCutcheon, J W
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1984 Português
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Nitrite has been used for centuries to preserve, color, and flavor meat. Today, about 10 billion pounds of cured meat products are produced annually, accounting for some one-tenth of the American food supply. Regulators became concerned about the safety of using nitrite in the early 1960s when studies showed the presence of carcinogenic nitrosamines in cured meat products. In the early 1970s, a study at the Massachusetts Institute of Technology implicated nitrite itself as a carcinogen. As studies have raised concern over the safety of nitrite, regulators have had to weigh the potential risk from cancer against nitrite's proven role in protecting consumers from deadly food poisoning bacteria. Today there is little scientific support for the theory that nitrite is a direct carcinogen. To deal with the nitrosamine problem, the U.S. Department of Agriculture (USDA) lowered the permissible amount of nitrite in cured meats to that level considered necessary for botulism protection. Regulators, however, found it necessary to take additional steps with bacon because nitrosamines were found consistently in fried bacon samples. In addition to lowering the amount of nitrite that could be added to "pumped bacon" (cured by injecting liquid curing agents in the pork belly)...

‣ Exposure to high concentrations of nitrosamines and cancer mortality among a cohort of rubber workers

Straif, K.; Weiland, S.; Bungers, M.; Holthenrich, D.; Taeger, D.; Yi, S.; Keil, U.
Fonte: BMJ Group Publicador: BMJ Group
Tipo: Artigo de Revista Científica
Publicado em /03/2000 Português
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OBJECTIVES—To examine if the occurrence of different cancers was increased among rubber workers, as the highest known exposures of humans to nitrosamines have occurred in the rubber industry.
METHODS—A cohort of 8933 rubber workers (hired after 1 January 1950, still active or retired on 1 January 1981 and employed for at least 1 year in one of five study factories) was followed up for mortality from 1 January 1981 to 31 December 1991. Work histories were reconstructed with routinely documented cost centre codes, which allowed identification by employment in specific work areas. For each cost centre code time and factory specific, semi-quantitative exposures to nitrosamines (three levels: low, medium, high) and other compounds were estimated by industrial hygienists. Rate ratios for medium (RRm) and high (RRh) exposures and 95% confidence intervals (95% CIs) were calculated with Cox's proportional hazards models with the low exposure as reference.
RESULTS—Exposure to nitrosamines was significantly associated with an increased mortality from cancers of the oesophagus (13 deaths: RRm 1.7, 95% CI 0.3 to 10.3; RRh 7.3, 95% CI 1.9 to 27.8) and of the oral cavity and pharynx (17 deaths: RRm 0.8, 95% CI 0.2 to 4.1; RRh 3.9...

‣ Determination of N-nitrosamines and N-nitrosables substances in rubber teats and sothers by GC-TEA

Vieira,Eleno Rodrigues; Pierozan,Nilso José; Lovison,Viviane
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2006 Português
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N-Nitrosamines are receiving special attention because they present high mutagenic and carcinogenic potential. They can be found in several areas. In rubber, for example, they can be found in Nipples and Pacifiers. Spiegelhalder and Pressumann, have observed that N-Nitrosamines present in nipples and pacifiers could easily migrate to artificial saliva. They have also observed that a considerable amount of N-Nitrosamines precursors, such as nitrosable amines, could migrate to saliva, increasing the possibility of N-Nitrosamines formation into the stomach of living beings. In 80's, Holland, Germany and FDA-U.S.A. have established volatile N-Nitrosamines limit levels. In 2002, in Brazil, limit levels came through Resolução RDC n° 221 of ANVISA. This resolution refers to NBR10334 and NBR 13793 standards where limits and analysis methods are specified. In this work SENAICETEPO presents the method adopted for determination of N-Nitrosamines and N-Nitrosables in nipples and pacifiers. The detection and determination limits of the analytical system as well the method uncertainty were evaluated, in order to demonstrate the adequacy of this technique to comply with the requirements of NBR10334/2003 and NBR 13793/2003 standard.

‣ Carcinogenic nitrosamines in traditional beer as the cause of oesophageal squamous cell carcinoma in black South Africans

Isaacson,C; Mothobi,P; Hale,M; Tomar,L K; Tyagi,C; Kumar,P; Choonara,Y E; Altini,M; Pillay,V
Fonte: SAMJ: South African Medical Journal Publicador: SAMJ: South African Medical Journal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 Português
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BACKGROUND: Before the 1930s, squamous cell carcinoma (SCC) of the oesophagus was almost unknown among black South Africans. From the 1930s the annual frequency rose. A dietary cause was sought, the staple diet of black people having changed from sorghum to maize (corn), with traditional beer being brewed from maize. Carcinogenic N-nitrosamines in traditional beer were suggested as a cause of SCC of the oesophagus, with Fusarium moniliforme, a corn saprophyte, thought to play a role. OBJECTIVES: To confirm the presence of N-nitrosamines in traditional beer and demonstrate a mechanism for the oncogenesis of oesophageal carcinoma. METHODS: Analysis by high-performance liquid chromatography was conducted for the identification of nitrosamines in traditional beer samples, and molecular docking studies were employed to predict the affinity between N-nitrosamines and the S100A2 protein. RESULTS: Carcinogenic N-nitrosamines were identified in all six samples of traditional beer examined (N=18 analyses), and docking studies confirmed a high affinity of the nitrosamine N-nitrosopyrrolidone with the S100A2 protein. This may result in the altered expression of the S100A2 protein, leading to tumour progression and prognosis. CONCLUSION: It is suggested that carcinogenic N-nitrosamines in traditional beer are a major factor in the causation of SCC of the oesophagus in black South Africans. N-nitrosamines have been shown to produce cancer experimentally...

‣ Nitrosamines: a review on their prevalence as emerging pollutants and potential remediation options

Mhlongo,Sthembile H; Mamba,Bhekie B; Krause,Rui W
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2009 Português
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This review provides an overview of the current state of knowledge on the prevalence of nitrosamines in drinking water, especially nitrosodimethylamine (NDMA), and discusses published research on the detection, mechanisms of formation, and removal of nitrosamines. While the number of published reports in the South African context is very limited, this review also attempts to contextualise and report specifically on the challenges for South Africa. Besides direct industrial or human-derived contamination, nitrosodimethylamine can be formed through a chemical reaction between monochloroamine and an organic-based compound such as dimethylamine which is frequently detected in surface water. It has been suggested that chloramination of surface waters with a high concentration of dissolved organic carbon (DOC) could result in elevated NDMA formation. Growing evidence suggests that NDMA occurs more frequently and at higher concentrations in drinking water systems that practise chloramination compared to systems that use chlorination.