Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Food Chem Toxicol ; 179: 113940, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37487858

RESUMO

In recent years, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) has conducted a program to re-evaluate the safety of natural flavor complexes (NFCs) used as flavor ingredients. This publication, twelfth in the series, details the re-evaluation of NFCs whose constituent profiles are characterized by alicyclic or linear ketones. In its re-evaluation, the Expert Panel applies a scientific constituent-based procedure for the safety evaluation of NFCs in commerce using a congeneric group approach. Estimated intakes of each congeneric group of the NFC are evaluated using the well-established and conservative Threshold of Toxicological Concern (TTC) approach. In addition, studies on the toxicity and genotoxicity of members of the congeneric groups and the NFCs under evaluation are reviewed. The scope of the safety evaluation of the NFCs contained herein does not include added use in dietary supplements or any products other than food. Thirteen (13) NFCs derived from the Boronia, Cinnamomum, Thuja, Ruta, Salvia, Tagetes, Hyssopus, Iris, Perilla and Artemisia genera are affirmed as generally recognized as safe (GRAS) under conditions of their intended use as flavor ingredients based on an evaluation of each NFC and the constituents and congeneric groups therein.


Assuntos
Produtos Biológicos , Tagetes , Aromatizantes , Indústria Alimentícia , Suplementos Nutricionais , Extratos Vegetais
2.
Food Chem Toxicol ; 174: 113643, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36739890

RESUMO

The FEMA Expert Panel program to re-evaluate the safety of natural flavor complexes (NFCs) used as flavoring ingredients in food has resulted in the publication of an updated constituent-based procedure as well as publications on the safety evaluation of many botanical-derived NFCs. This publication, ninth in the series and related to the ninth publication, describes the affirmation of the generally recognized as safe (GRAS) status for NFCs with propenylhydroxybenzene and allylalkoxybenzene constituents under their conditions of intended use as flavoring ingredients added to food. The Panel's procedure applies the threshold of toxicological concern (TTC) concept and evaluates relevant data on absorption, metabolism, genotoxic potential and toxicology for the NFCs themselves and their respective constituent congeneric groups. For NFCs containing allylalkoxybenzene constituent(s) with suspected genotoxic potential, the estimated intake of the individual constituent is compared to the TTC for compounds with structural alerts for genotoxicity and if exceeded, a margin of exposure is calculated using BMDL10 values derived from benchmark dose analyses using Bayesian model averaging, as presented in the tenth article of the series. Safety evaluations for NFCs derived from allspice, anise seed, star anise, sweet fennel seed and pimento leaves were conducted and their GRAS status was affirmed for use as flavoring ingredients. The scope of the safety evaluation contained herein does not include added use in dietary supplements or any products other than food.


Assuntos
Foeniculum , Pimenta , Pimpinella , Testes de Toxicidade , Teorema de Bayes , Aromatizantes/toxicidade , Suplementos Nutricionais
3.
Food Chem Toxicol ; 173: 113580, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36610475

RESUMO

The Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) applies its procedure for the safety evaluation of natural flavor complexes (NFCs) to re-evaluate the safety of Asafetida Oil (Ferula assa-foetida L.) FEMA 2108, Garlic Oil (Allium sativum L.) FEMA 2503 and Onion Oil (Allium cepa L.) FEMA 2817 for use as flavoring in food. This safety evaluation is part of a series of evaluations of NFCs for use as flavoring ingredients conducted by the Expert Panel that applies a scientific procedure published in 2005 and updated in 2018. Using a group approach that relies on a complete chemical characterization of the NFC intended for commerce, the constituents of each NFC are organized into well-defined congeneric groups and the estimated intake of each constituent congeneric group is evaluated using the conservative threshold of toxicological concern (TTC) concept. Data on the metabolism, genotoxic potential and toxicology for each constituent congeneric group are reviewed as well as studies on each NFC. Based on the safety evaluation, Asafetida Oil (Ferula assa-foetida L.), Garlic Oil (Allium sativum L.) and Onion Oil (Allium cepa L.) were affirmed as generally recognized as safe (GRASa) under their conditions of intended use as flavor ingredients.


Assuntos
Produtos Biológicos , Ferula , Alho , Aromatizantes/toxicidade , Aromatizantes/química , Óleos de Plantas/toxicidade
4.
Food Chem Toxicol ; 155: 112357, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34217737

RESUMO

In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a program for the re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavor ingredients. This publication, the sixth in the series, will summarize the re-evaluation of eight NFCs whose constituent profiles are characterized by significant amounts of eucalyptol and/or other cyclic ethers. This re-evaluation was based on a procedure first published in 2005 and subsequently updated in 2018 that evaluates the safety of naturally occurring mixtures for their intended use as flavoring ingredients. The procedure relies on a complete chemical characterization of the NFC intended for commerce and the organization of its chemical constituents into well-defined congeneric groups. The safety of the NFC is evaluated using the well-established and conservative threshold of toxicological concern (TTC) concept in addition to data on absorption, metabolism and toxicology of the constituents of the congeneric groups and the NFC under evaluation. Eight NFCs derived from the Eucalyptus, Melaleuca, Origanum, Laurus, Rosmarinus and Salvia genera were affirmed as generally recognized as safe (GRAS) under their conditions of intended use as flavor ingredients based on an evaluation of each NFC and the constituents and congeneric groups therein.


Assuntos
Éteres Cíclicos/toxicidade , Aromatizantes/toxicidade , Óleos de Plantas/toxicidade , Animais , Células CHO , Linhagem Celular Tumoral , Qualidade de Produtos para o Consumidor , Cricetulus , Éteres Cíclicos/química , Eucaliptol/toxicidade , Feminino , Aromatizantes/química , Humanos , Masculino , Camundongos , Testes de Mutagenicidade , Nível de Efeito Adverso não Observado , Óleos de Plantas/química , Plantas/química , Gravidez , Ratos Wistar , Medição de Risco , Salmonella typhimurium/efeitos dos fármacos
5.
Food Chem Toxicol ; 155: 112378, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34217738

RESUMO

In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavor ingredients, mostly consisting of a variety of essential oils and botanical extracts. This publication, seventh in the series, re-evaluates NFCs with constituent profiles dominated by phenolic derivatives including carvacrol, thymol and related compounds using a constituent-based procedure first published in 2005 and updated in 2018. The procedure is based on the chemical characterization of each NFC as intended for commerce and the estimated intake of the constituent congeneric groups. The procedure applies the threshold of toxicological concern (TTC) concept and evaluates relevant data on absorption, metabolism, genotoxic potential and toxicology of the constituent congeneric groups and the NFC under evaluation. Herein, the FEMA Expert Panel affirmed the generally recognized as safe (GRAS) status of seven phenolic derivative-based NFCs, Origanum Oil (Extractive) (FEMA 2828), Savory Summer Oil (FEMA 3013), Savory Summer Oleoresin (FEMA 3014), Savory Winter Oil (FEMA 3016), Savory Winter Oleoresin (FEMA 3017), Thyme Oil (FEMA 3064) and Thyme White Oil (FEMA 3065) under their conditions of intended use as flavor ingredients.


Assuntos
Aromatizantes/toxicidade , Óleos Voláteis/toxicidade , Fenóis/toxicidade , Óleos de Plantas/toxicidade , Animais , Qualidade de Produtos para o Consumidor , Escherichia coli/efeitos dos fármacos , Feminino , Aromatizantes/química , Masculino , Camundongos Endogâmicos ICR , Testes de Mutagenicidade , Nível de Efeito Adverso não Observado , Óleos Voláteis/química , Origanum/química , Fenóis/química , Óleos de Plantas/química , Ratos Sprague-Dawley , Ratos Wistar , Medição de Risco , Salmonella typhimurium/efeitos dos fármacos , Thymus (Planta)/química
6.
Toxicol Mech Methods ; 30(9): 656-671, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32746684

RESUMO

Pyroxasulfone induced a low incidence of urinary bladder tumors in male rats in a 2-year bioassay at 1000 and 2000 ppm, with occasional urinary calculi. No increased incidence of tumors of any tissue occurred in female rats or in mice of either gender. We performed three short-term studies to evaluate early development of pyroxasulfone-induced urinary crystals and urothelial cytotoxicity with consequent regenerative proliferation. First, male rats were treated with dietary 50, 1000 or 2000 ppm pyroxasulfone for 1, 3 or 7 days. The urothelium was examined by light and scanning electron microscopy (LM, SEM) and bromodeoxyuridine labeling index (BrdU LI). In two other studies, male rats were treated with dietary 20 000 ppm pyroxasulfone for 1 week. Urine collected at various times of day was examined by SEM and energy dispersive spectroscopy (EDS) or by LM, SEM, EDS, and infrared spectroscopy (IFS). Urinary crystals were present at various time points. EDS and IFS showed some contained calcium; others contained organic matter. Cytotoxicity was detected by SEM as cellular swelling, craters, and necrosis and by LM as cellular hypertrophy. Increased cell proliferation was detected by LM (hyperplasia), SEM (piling up of round cells), and by increased BrdU LI. There was no evidence of increased apoptosis. These findings support a mode of action for pyroxasulfone-associated bladder tumors in male rats involving formation of urinary crystals leading to urothelial cytotoxicity and regenerative proliferation. This is a high dose phenomenon, therefore, pyroxasulfone is not likely to be carcinogenic to humans at exposure levels that do not cause crystals with subsequent calculi formation in the urinary tract.


Assuntos
Proliferação de Células/efeitos dos fármacos , Herbicidas/toxicidade , Isoxazóis/toxicidade , Sulfonas/toxicidade , Neoplasias da Bexiga Urinária/induzido quimicamente , Cálculos Urinários/induzido quimicamente , Urotélio/efeitos dos fármacos , Animais , Testes de Carcinogenicidade , Cristalização , Relação Dose-Resposta a Droga , Hiperplasia , Masculino , Necrose , Ratos Sprague-Dawley , Medição de Risco , Fatores de Tempo , Neoplasias da Bexiga Urinária/patologia , Cálculos Urinários/urina , Urotélio/ultraestrutura
7.
Food Chem Toxicol ; 145: 111585, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32702506

RESUMO

In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association initiated the safety re-evaluation of over 250 natural flavor complexes (NFCs) used as flavor ingredients. This publication, 4th in a series focusing on the safety evaluation of NFCs, presents an evaluation of NFCs rich in hydroxyallylbenzene and hydroxypropenylbenzene constituents using a procedure initially published in 2005 and updated in 2018 that evaluates the safety of naturally occurring mixtures for their intended use as flavoring ingredients. The procedure requires the characterization of the chemical composition for each NFC and subsequent organization of the constituents into defined congeneric groups. The safety of each NFC is evaluated using the conservative threshold of toxicological concern (TTC) approach together with studies on absorption, metabolism and toxicology of the NFC and its constituent congeneric groups. By the application of this procedure, seven NFCs, derived from clove, cinnamon leaf and West Indian bay leaf were affirmed as "generally recognized as safe (GRAS)" under their conditions of intended use as flavor ingredients. An eighth NFC, an oleoresin of West Indian bay leaf, was affirmed based on its estimated intake, which is below the TTC of 0.15 µg/person per day for compounds with structural alerts for genotoxicity.


Assuntos
Cinnamomum zeylanicum/química , Aromatizantes/toxicidade , Laurus/química , Syzygium/química , Derivados de Alilbenzenos , Animais , Anisóis/química , Anisóis/toxicidade , Qualidade de Produtos para o Consumidor , Escherichia coli/efeitos dos fármacos , Eugenol/química , Eugenol/toxicidade , Feminino , Aromatizantes/química , Humanos , Masculino , Camundongos , Testes de Mutagenicidade , Nível de Efeito Adverso não Observado , Óleos de Plantas/química , Óleos de Plantas/toxicidade , Ratos , Safrol/química , Safrol/toxicidade , Salmonella typhimurium/efeitos dos fármacos
8.
Food Chem Toxicol ; 145: 111584, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32682832

RESUMO

In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a program for the re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavor ingredients. This publication, fifth in the series, evaluates the safety of NFCs containing linalool and/or other characteristic mono- and sesquiterpenoid tertiary alcohols and esters using the safety evaluation procedure published by the FEMA Expert Panel in 2005 and updated in 2018. The procedure relies on a complete chemical characterization of the NFC intended for commerce and organization of the chemical constituents of each NFC into well-defined congeneric groups. The safety of each NFC is evaluated using the well-established and conservative threshold of toxicological concern (TTC) concept in addition to data on absorption, metabolism and toxicology of both the constituent congeneric groups and the NFCs. Sixteen NFCs, derived from the Lavandula, Aniba, Elettaria, Daucus, Salvia, Coriandrum, Ribes, Guaiacum/Bulnesia, Citrus, Pogostemon, Melaleuca and Michelia genera, were affirmed as generally recognized as safe (GRAS) under their conditions of intended use as flavor ingredients based on an evaluation of each NFC and the constituents and congeneric groups therein.


Assuntos
Aromatizantes/toxicidade , Monoterpenos/toxicidade , Plantas/química , Sesquiterpenos/toxicidade , Animais , Qualidade de Produtos para o Consumidor , Escherichia coli/efeitos dos fármacos , Feminino , Aromatizantes/química , Humanos , Masculino , Camundongos , Monoterpenos/química , Testes de Mutagenicidade , Nível de Efeito Adverso não Observado , Óleos de Plantas/química , Óleos de Plantas/toxicidade , Ratos , Salmonella typhimurium/efeitos dos fármacos , Sesquiterpenos/química
9.
Food Chem Toxicol ; 135: 110949, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31751643

RESUMO

In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a program for the re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavor ingredients. This publication, third in the series, considers NFCs composed primarily of constituents with the 3-phenyl-2-propenyl or a cinnamyl functional group, using the procedure outlined in 2005 and updated in 2018 to evaluate the safety of naturally-occurring mixtures for their intended use as flavor ingredients. The procedure relies on a complete chemical characterization of the NFC intended for commerce and organization of each NFC's chemical constituents into well-defined congeneric groups. The safety of the NFC is evaluated using the well-established and conservative threshold of toxicological concern (TTC) concept in addition to data on absorption, metabolism and toxicology of members of the congeneric groups and the NFC under evaluation. Six NFCs from the Myroxylon and Cinnamomum genera, Balsam Oil, Peru (FEMA 2117), Tolu Balsam Extract (FEMA 3069), Cassia Bark Extract (FEMA 2257), Cassia Bark Oil (FEMA 2258), Cinnamon Bark Extract (FEMA 2290) and Cinnamon Bark Oil (FEMA 2291) were evaluated and affirmed as generally recognized as safe (GRAS) under their conditions of intended use as flavor ingredients.


Assuntos
Cinnamomum/química , Aromatizantes/toxicidade , Myroxylon/química , Óleos Voláteis/toxicidade , Extratos Vegetais/toxicidade , Animais , Linhagem Celular , Qualidade de Produtos para o Consumidor , Aromatizantes/química , Humanos , Nível de Efeito Adverso não Observado , Óleos Voláteis/química , Extratos Vegetais/química , Medição de Risco
10.
Food Chem Toxicol ; 135: 110870, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31604112

RESUMO

In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavor ingredients. NFC flavor materials include a variety of essential oils and botanical extracts. The re-evaluation of NFCs is conducted based on a constituent-based procedure outlined in 2005 and updated in 2018 that evaluates the safety of NFCs for their intended use as flavor ingredients. This procedure is applied in the re-evaluation of the generally recognized as safe (GRAS) status of NFCs with constituent profiles that are dominated by alicyclic ketones such as menthone and carvone, secondary alcohols such as menthol and carveol, and related compounds. The FEMA Expert Panel affirmed the GRAS status of Peppermint Oil (FEMA 2848), Spearmint Oil (FEMA 3032), Spearmint Extract (FEMA 3031), Cornmint Oil (FEMA 4219), Erospicata Oil (FEMA 4777), Curly Mint Oil (FEMA 4778), Pennyroyal Oil (FEMA 2839), Buchu Leaves Oil (FEMA 2169), Caraway Oil (FEMA 2238) and Dill Oil (FEMA 2383) and determined FEMA GRAS status for Buchu Leaves Extract (FEMA 4923), Peppermint Oil, Terpeneless (FEMA 4924) and Spearmint Oil, Terpeneless (FEMA 4925).


Assuntos
Produtos Biológicos/química , Aromatizantes/farmacologia , Extratos Vegetais/farmacologia , Plantas/química , Aromatizantes/normas , Estados Unidos , United States Food and Drug Administration
11.
Toxicol Sci ; 130(2): 281-8, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22923491

RESUMO

Diuron, a substituted urea herbicide, is carcinogenic to the rat urinary bladder at high dietary levels (2500 ppm). To further elucidate the mode of action, this study aimed to determine the time course and sequence of bladder cytotoxic and proliferative changes induced by diuron treatment of male Wistar rats. Rats were randomized into two groups (control and 2500 ppm diuron) and treated for 28 days. Ten rats from each group were terminated on each of study days 1, 3, 7, or 28. Scanning electron micro scopy (SEM) showed urothelial cell swelling beginning on day 1, and by day 28, showed extensive necrosis, exfoliation and piling up of cells suggestive of hyperplasia. No difference in the bromo deoxyuridine labeling index was detected. In a second experiment, rats were randomized into control and diuron-treated groups and treated for 7 days or 8 weeks. After 7 days, transmission electron microscopy showed cell degenerative changes and distention of the cytoplasm, organelles, and nuclei characteristic of cytolysis. This resulted in protrusion of the superficial cells into the lumen, corresponding to the cell swelling observed previously by SEM. After 8 weeks, bladders in the diuron-treated group showed an increased incidence of simple hyperplasia by light microscopy (6/10, p < 0.05) compared with controls (0/10) and a significantly different SEM classification. In summary, our results support the hypothesis that urothelial cytotoxicity followed by regenerative cell proliferation are the sequential key events that occur with high-dose diuron exposure in rats.


Assuntos
Diurona/toxicidade , Células Epiteliais/efeitos dos fármacos , Herbicidas/toxicidade , Bexiga Urinária/efeitos dos fármacos , Urotélio/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Tamanho Celular/efeitos dos fármacos , Ingestão de Líquidos/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Células Epiteliais/ultraestrutura , Hiperplasia , Rim/efeitos dos fármacos , Rim/patologia , Masculino , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Necrose , Ratos , Ratos Wistar , Regeneração/efeitos dos fármacos , Fatores de Tempo , Bexiga Urinária/ultraestrutura , Urotélio/ultraestrutura
12.
Biomaterials ; 32(23): 5417-26, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21536326

RESUMO

Nanogels are comprised of swollen polymer networks and nearly 95% water and can entrap diverse chemical and biological agents for cancer therapy with very high loading capacities. Here we use diblock copolymer poly(ethylene oxide)-b-poly(methacrylic acid) (PEO-b-PMA) to form nanogels with the desired degree of cross-linking. The nanogels are further conjugated to folic acid (FA) and loaded with different types of drugs (cisplatin, doxorubicin). For the first time we demonstrate a tumor-specific delivery and superior anti-tumor effect in vivo of an anti-cancer drug using these polyelectrolyte nanogels decorated with folate-targeting groups. This reinforces the use of nanogels for the therapy of ovarian and other cancers, where folate receptor (FR) is overexpressed.


Assuntos
Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Sistemas de Liberação de Medicamentos/métodos , Ácido Fólico/química , Hidrogéis/química , Nanopartículas/química , Neoplasias Ovarianas/tratamento farmacológico , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Disponibilidade Biológica , Peso Corporal/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/administração & dosagem , Cisplatino/química , Cisplatino/farmacocinética , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Doxorrubicina/administração & dosagem , Doxorrubicina/química , Doxorrubicina/farmacocinética , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Endocitose/fisiologia , Feminino , Humanos , Hidrogéis/síntese química , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Luz , Camundongos , Camundongos Nus , Microscopia de Força Atômica , Concentração Osmolar , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Tamanho da Partícula , Platina/metabolismo , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Espalhamento de Radiação , Eletricidade Estática , Propriedades de Superfície , Análise de Sobrevida , Água/química , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Regul Toxicol Pharmacol ; 59(3): 430-6, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21296119

RESUMO

An independent Pathology Working Group (PWG) re-evaluated the kidney changes in National Toxicology Program (NTP) toxicology/carcinogenicity studies of tert-butyl alcohol (TBA) in F344/N rats to determine possible mode(s) of action underlying renal tubule tumors in male rats at 2-years. In the 13-week study, the PWG confirmed that the normal pattern of round hyaline droplets in proximal convoluted tubules was replaced by angular droplet accumulation, and identified precursors of granular casts in the outer medulla, changes typical of alpha(2u)-globulin (α(2u)-g) nephropathy. In the 2-year study, the PWG confirmed the NTP observation of increased renal tubule tumors in treated male groups. Linear papillary mineralization, another hallmark of the α(2u)-g pathway was present only in treated male rats. Chronic progressive nephropathy (CPN) was exacerbated in high-dose males and females, with a relationship between advanced grades of CPN and renal tumor occurrence. Hyperplasia of the papilla lining was a component of CPN in both sexes, but there was no pelvic urothelial hyperplasia. High-dose females showed no TBA-related nephrotoxicity. The PWG concluded that both α(2u)-g nephropathy and exacerbated CPN modes of action were operative in TBA renal tumorigenicity in male rats, neither of which has relevance for human cancer risk.


Assuntos
Ingestão de Líquidos , Rim/efeitos dos fármacos , Rim/patologia , Água , terc-Butil Álcool/toxicidade , Animais , Testes de Carcinogenicidade/métodos , Avaliação Pré-Clínica de Medicamentos/métodos , Feminino , Neoplasias Renais/induzido quimicamente , Neoplasias Renais/patologia , Masculino , Ratos , Ratos Endogâmicos F344 , Testes de Toxicidade/métodos , Água/administração & dosagem , terc-Butil Álcool/administração & dosagem
14.
Toxicol Lett ; 187(2): 124-9, 2009 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-19429254

RESUMO

Arsenite (As(III)), an inorganic arsenical, is a known human carcinogen, inducing tumors of the skin, urinary bladder and lung. It is known to be metabolized to organic methylated arsenicals in vivo. As(III) has been reported to have the ability to up-regulate the epidermal growth factor receptor (EGFR)-associated pathway in epithelial cells, including human urothelial cells in vitro. EGFR is a cell-surface receptor belonging to the ErbB family of receptor tyrosine kinases, and the EGFR-associated signaling pathway has been reported to play an important role in carcinogenesis and cancer progression, including in bladder cancer. In this study, we investigated the growth effects of As(III) and an organic trivalent arsenical, dimethylarsinous acid (DMA(III)), and the effects of co-exposure of gefitinib, an EGFR inhibitor, with As(III) to a rat urothelial cell line (MYP3). We also investigated the effects of co-administration of dietary As(III) and gefitinib in vivo. In vitro, concentrations of 1.0microM As(III) or 0.5microM DMA(III) induced cytotoxicity. However, lower concentrations of As(III) treatment had a slight mitogenic growth effect whereas lower concentrations of DMA(III) did not. Gefitinib blocked As(III)-induced cell growth in vitro. In vivo, a high dose of gefitinib alone induced slight urothelial cytotoxicity, and did not reduce cytotoxicity and regenerative cell proliferation when co-administered with As(III). The majority of arsenic metabolites present in the urine of As(III)-treated rats were organic arsenicals, mainly dimethylarsinic acid (DMA(V)). As(III) was also present, and its concentration was higher than the concentration required to produce cytotoxicity in vitro. These data suggest that an EGFR inhibitor has the ability to block As(III)-induced cell proliferation in vitro but not in vivo in a short-term study.


Assuntos
Arsenitos/toxicidade , Ácido Cacodílico/análogos & derivados , Receptores ErbB/antagonistas & inibidores , Quinazolinas/farmacologia , Bexiga Urinária/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Ácido Cacodílico/toxicidade , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ingestão de Líquidos/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Gefitinibe , Histocitoquímica , Distribuição Aleatória , Ratos , Ratos Endogâmicos F344 , Bexiga Urinária/enzimologia
15.
Crit Rev Toxicol ; 38(10): 817-45, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18853291

RESUMO

To predict important strategic issues in product safety during the next 10 years, the Health and Environmental Sciences Institute (HESI) of the International Life Sciences Institute initiated a mapping exercise to evaluate which issues are likely to be of societal, scientific, and regulatory importance to regulatory authorities, the HESI membership, and the scientific community at large. Scientists representing government, academia, and industry participated in the exercise. Societal issues identified include sensitive populations, alternative therapies, public education on the precautionary principle, obesity, and aging world populations. Scientific issues identified include cancer testing, children's health, mixtures and co-exposures, sensitive populations, idiosyncratic reactions, "omics" or bioinformatics, and environmental toxicology. Regulatory issues identified include national and regional legislation on chemical safety, exposure inputs, new technologies, transitioning new science into regulations and guidelines, conservative default factors, data quality, and sensitive populations. Because some issues were identified as important in all three areas (e.g. sensitive populations), a comprehensive approach to assessment and management is needed to ensure consideration of societal, scientific, and regulatory implications. The resulting HESI Combined Challenges Map is not intended to offer a universal description of challenges in safety assessment, nor is it intended to address, advocate, or manage the prioritized issues. Rather, the map focuses on and predicts issues likely to be central to the strategic agendas of individual companies and regulatory authorities in the developed world. Many of these issues will become increasingly important in the future in rapidly developing economies, such as India and China. The scientific mapping exercise has particular value to the toxicology community because it represents the contributions of key scientists from around the world from government, academia, and industry.


Assuntos
Ecologia/métodos , Saúde Ambiental/métodos , Monitoramento Ambiental , Saúde Pública/tendências , Medição de Risco/métodos , Ecologia/legislação & jurisprudência , Ecologia/tendências , Exposição Ambiental/prevenção & controle , Saúde Ambiental/legislação & jurisprudência , Saúde Ambiental/tendências , Humanos , Medição de Risco/legislação & jurisprudência , Medição de Risco/tendências
16.
Food Chem Toxicol ; 45(1): 98-106, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17034924

RESUMO

Groups of Fischer 344 rats (20/sex/group) received control or treated diets at levels of 0, 25,000 or 50,000 ppm kappa carrageenan with a molecular weight range (Mw) of 196,000-257,000 Da for 90 days. The Low Molecular Weight Tail (LMT) ranged between 1.9% and 12.0%<50 kDa (mean 7%) based on the results of a program initiated to develop a validated analytical method to measure the LMT. This is the first GLP dietary study in which carrageenan is characterized by percentage LMT. Clinical examinations were performed daily. Individual food consumption/body weight measurements were made weekly. Ophthalmic exam was conducted prior to and at the end of treatment. Hematology/serum chemistry and urinalysis evaluations were done at necropsy, as were organ weight determinations for adrenals, brain, heart, kidneys, liver, ovaries, spleen, testes and thyroid with parathyroids. Full histopathological evaluation of organs was conducted on the control and 50,000 ppm groups, including hematoxylin-eosin-stained cross sections of paraffin-embedded rolled colon. Clinical signs were limited to soft feces in high dose rats and to a lesser extent in low dose rats. There were no treatment-related effects on body weights, urinalysis, hematology or clinical chemistry parameters, or on organ weights or ophthalmic, macroscopic or microscopic findings. The gastrointestinal tract appeared normal in detailed histopathological evaluation using the Swiss roll technique. The NOAEL is 50,000 ppm in the diet (mean calculated test material consumption of 3394+/-706 mg/kg/day in males, 3867+/-647 mg/kg/day in females). The results of the study provide evidence that it is not necessary to characterize carrageenan by a specification for LMT (less than 5% below 50 kDa) as has been done in Commission Directive 2004/45/EC of 16 April 2004 (Commission Directive, 2004/45/EC of 16 April 2004 amending Directive 96/77/EC laying down specific purity criteria on food additives other than colors and sweeteners. Official Journal of European Union 20 April, 2004, L113/19-L113/21).


Assuntos
Carragenina/toxicidade , Aditivos Alimentares/toxicidade , Trato Gastrointestinal/efeitos dos fármacos , Administração Oral , Animais , Peso Corporal/efeitos dos fármacos , Carragenina/química , Carragenina/classificação , Testes de Química Clínica , Diarreia/induzido quimicamente , Dieta , Relação Dose-Resposta a Droga , Ingestão de Alimentos , União Europeia , Feminino , Aditivos Alimentares/química , Trato Gastrointestinal/patologia , Testes Hematológicos , Técnicas Histológicas , Masculino , Peso Molecular , Nível de Efeito Adverso não Observado , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Endogâmicos F344
17.
Toxicol Sci ; 96(1): 58-71, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17132713

RESUMO

Muraglitazar, a PPARalpha/gamma dual agonist, was dosed orally to rats once daily for 13 weeks to evaluate urinary and urothelial changes of potential relevance to urinary bladder tumorigenesis. Groups of 17 young or aged rats per sex were fed a normal or 1% NH4Cl-supplemented diet and were dosed with 0, 1, or 50 mg/kg muraglitazar. Lithogenic ions and sediment were profiled from freshly voided urine samples collected 24 h after dosing, and drug exposures were measured. Urinary citrate, oxalate, and epidermal growth factor (EGF) were assayed from 18-h urine collections. Urothelium was assessed by light microscopy, scanning electron microscopy, and BrdU and TUNEL immunohistochemistry. When fed a normal diet, urine pH was higher in males (above 6.5). Urine volume/body weight was greater in females. Urine soluble/total calcium and magnesium and phosphorus/creatinine ratios were lower in male rats fed a normal diet. Urine citrate levels were decreased and oxalate was increased in young male rats treated with 50 mg/kg muraglitazar compared to age/sex/diet-matched controls. No changes in urine sediment were detected 24 h after dosing. In young male rats treated with 50 mg/kg on normal diet, multifocal urothelial necrosis and proliferation were observed, whereas urothelial apoptosis and urine EGF levels were unchanged compared to age/sex/diet-matched controls. Urothelial necrosis and proliferation were not correlated to systemic or urinary drug exposures and were prevented by dietary acidification. These data suggest that muraglitazar-associated changes in urine composition predispose to urothelial cytotoxicity and proliferation in the urinary bladder of young male rats and that urine sediment must be profiled at multiple daily timepoints to fully qualify drug-induced changes in urine composition.


Assuntos
Glicina/análogos & derivados , Oxazóis/toxicidade , PPAR alfa/agonistas , PPAR gama/agonistas , Proliferadores de Peroxissomos/toxicidade , Bexiga Urinária/efeitos dos fármacos , Fatores Etários , Animais , Apoptose/efeitos dos fármacos , Cálcio/urina , Proliferação de Células/efeitos dos fármacos , Citratos/urina , Creatinina/urina , Relação Dose-Resposta a Droga , Fator de Crescimento Epidérmico/urina , Feminino , Glicina/toxicidade , Glicina/urina , Hiperplasia , Magnésio/urina , Masculino , Oxalatos/urina , Oxazóis/urina , Proliferadores de Peroxissomos/urina , Fósforo/urina , Ratos , Ratos Sprague-Dawley , Fatores Sexuais , Fatores de Tempo , Bexiga Urinária/ultraestrutura , Urina/química , Urotélio/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA