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Regulatory Toxicology and Pharmacology: RTP

Christina L Zuch de Zafra, Vito G Sasseville, Steven Matsumoto, Christian Freichel, Mark Milton, Timothy K MacLachlan, Cindy Farman, Iona Raymond, Swati Gupta, Ronald Newton, Elke-Astrid Atzpodien, Evan A Thackaberry
No abstract text is available yet for this article.
April 18, 2017: Regulatory Toxicology and Pharmacology: RTP
Yonglin Gao, Yunzhi Wang, Yanshen Li, Rui Han, Chunmei Li, Lin Xiao, Susan Cho, Yukui Ma, Chao Fang, Albert W Lee
In this study, Beagle dogs were administered xylooligosaccharide (XOS, CAS # 87099-0) at doses of 0, 1250, 2500, and 5000 mg/kg/day by oral gavage for 26 weeks. A 4-week recovery period was added to observe delayed or reversible toxicity. Measurements included body weight, food consumption, clinical observations, temperature, electrocardiogram (ECG), urinalysis, blood chemistry, hematology, organ weight, gross necropsy, and histopathological examination. Except for transient diarrhea or vomiting, no treatment-related adverse effects were noted...
April 17, 2017: Regulatory Toxicology and Pharmacology: RTP
Kushal Kumar, Sabeena Sharma, Ashish Kumar, Pushpender Bhardwaj, Kalpana Barhwal, Sunil Kumar Hota
Nymphaea x rubra Roxb. ex Andrews (N. rubra) has been widely reported for immunomodulatory properties and treatment of piles, bleeding nose and dysentery in traditional medicinal systems. However, its in-vitro and in-vivo toxicity studies have never been investigated. So, the present study was designed to investigate in-vitro and in-vivo toxicity of methanolic extract of N. rubra rhizome in rats. In-vitro cytotoxicity studies were conducted for different doses of extract in N2a cell lines. For in-vivo toxicity studies, SD rats were divided into three groups and administered with 0, 300 and 2000 mg/kg b...
April 13, 2017: Regulatory Toxicology and Pharmacology: RTP
Chunmei Li, Yonglin Gao, Yunzhi Wang, Guisheng Li, Xiaochen Fan, Yanshen Li, Chenghua Guo, Jun Tao
As part of a safety evaluation, we evaluated the potential genotoxicity of sodium formononetin-3'-sulphonate (Sul-F) using bacterial reverse mutation assay, chromosomal aberrations detection, and mouse micronucleus test. In bacterial reverse mutation assay using five strains of Salmonella typhimurium (TA97, TA98, TA100, TA102 and TA1535), Sul-F (250, 500, 1000, 2000, 4000 μg/plate) did not increase the number of revertant colonies in any tester strain with or without S9 mix. In a chromosomal assay using Chinese hamster lung fibroblast (CHL) cells, there were no increases in either kind of aberration at any dose of Sul-F (400, 800, and 1600 μg/mL) treatment groups with or without S9 metabolic activation...
April 10, 2017: Regulatory Toxicology and Pharmacology: RTP
Zheng Liu, Dongying Liu, Jianguo Cheng, Song Mei, Ying Fu, Weiqi Lai, Yin Wang, Yihong Xu, Trung D Vo, Barry S Lynch
To assess the potential safety of lipid soluble green tea extract, also referred to as lipid soluble tea polyphenols (LSTP), a series of genotoxicity tests were conducted, including an Ames, in vivo mouse micronucleus, and in vivo mouse sperm abnormality test. The toxicity of LSTP was evaluated in 90- and 30-day feeding studies. LSTP did not show mutagenic activity in the Ames test and no genotoxic potential in the in vivo assays at doses up to 10 g/kg body weight (bw). In the 90-day feeding study, LSTP was given in the diet at levels providing 0, 0...
April 4, 2017: Regulatory Toxicology and Pharmacology: RTP
Kuriakose Jayesh, Lal Raisa Helen, A Vysakh, Eldhose Binil, M S Latha
Terminalia bellirica (Gaertn.) Roxb. (Family: Combretaceae), known as Bhibhitaki in Sanskrit and locally known as Behera in India is one of the oldest medicinal plants which has widely been used in the traditional system of medicine, especially in Ayurveda for centuries. The dried fruit of Terminalia bellirica is used for treating various ailments. Aqueous acetone extract of Terminalia bellirica (Gaertn.) Roxb fruits (AATB), showed antioxidant potential in our screening study is selected for the present in vivo toxicity evaluation...
April 4, 2017: Regulatory Toxicology and Pharmacology: RTP
Jacquelin Jolette, Bassem Attalla, Aurore Varela, Gerald G Long, Nacera Mellal, Sabile Trimm, Susan Y Smith, Michael S Ominsky, Gary Hattersley
Prolonged treatment with human parathyroid hormone (hPTH) in rats results in development of bone tumors, though this finding has not been supported by clinical experience. The PTH type 1 receptor agonist abaloparatide, selected for its bone anabolic activity, is under clinical development to treat postmenopausal women with osteoporosis. To determine the carcinogenic potential of abaloparatide, Fischer (F344) rats were administered SC daily abaloparatide at doses of 0, 10, 25, and 50 μg/kg or 30 μg/kg hPTH(1-34) as a positive control for up to 2 years...
April 4, 2017: Regulatory Toxicology and Pharmacology: RTP
Sandra Costigan, Juan Lopez-Belmonte
Many flavours and fragrances are known allergens. Their selection and inclusion levels in e-liquids must therefore be guided by toxicological principles, taking into account the exposure pattern and inhalation route of exposure. For contact sensitisation, a general, agreed quantitative risk assessment approach to prevent dermal sensitisation exists. Here we propose exposure parameters and safety factors to apply this approach to e-liquid ingredients. Additionally, as a risk management approach for pre-sensitised individuals, we derive a threshold of 0...
April 4, 2017: Regulatory Toxicology and Pharmacology: RTP
Rachel Hemingway, Adrian Fowkes, Richard V Williams
Carbamates are widely used in the chemical industry so understanding their toxicity is important to safety assessment. Carbamates have been associated with certain toxicities resulting in publication of structural alerts, including alerts for mutagenicity. Structural alerts for bacterial mutagenicity can be used in combination with statistical systems to enable ICH M7 classification, which allows assessment of the genotoxic risk posed by pharmaceutical impurities. This study tested a hypothetical bacterial mutagenicity alert for carbamates and examined the impact it would have on ICH M7 classifications using QSAR predictions from the expert rule-based system Derek Nexus and the statistical-based system Sarah Nexus...
April 3, 2017: Regulatory Toxicology and Pharmacology: RTP
Julie E Goodman, Michael K Peterson, Mary L Hixon, Sara Pacheco Shubin
Bisphenol A (BPA) is a high production volume chemical that is used in plastics and epoxy coatings. In 2015, California's Office of Environmental Health Hazard Assessment (OEHHA) added BPA to the Proposition 65 list of chemicals "known to cause reproductive toxicity" based on its Developmental and Reproductive Toxicant Identification Committee's (DART-IC) conclusion that BPA has been shown to cause female reproductive toxicity. A critical factor in determining compliance with Proposition 65 is a Maximum Allowable Dose Level (MADL), which is the exposure level at which a chemical would have no observable reproductive effect even if a person were exposed to 1000 times that level...
April 1, 2017: Regulatory Toxicology and Pharmacology: RTP
Juergen Pauluhn
This paper compares the pulmonary kinetics of inhaled nano-CeO2 from published repeated inhalation studies of 1-, 4-, 13-, and 52-week duration using a previously published kinetic model to simulate the pulmonary kinetics of inhaled micron-sized poorly soluble, low toxicity particles (PSPs) in rats. This comparative analysis demonstrates that the kinetic hallmarks characterizing lung overload-related pulmonary inflammation are indistinguishable for PSPs and agglomerated nano-CeO2. Unlike PSPs, nano-CeO2 appears to dissolve within the lung as long as tissue saturation has not been attained...
April 1, 2017: Regulatory Toxicology and Pharmacology: RTP
Michael Dourson, Jeri Higginbotham, Jeff Crum, Heather Burleigh-Flayer, Patricia Nance, Norman Forsberg, Mark Lafranconi
Previous work has shown that the weight of evidence supports the hypothesis that 1,4-dioxane causes liver tumors in rodents through cytotoxicity and subsequent regenerative hyperplasia. Questions regarding a lack of concordant findings for this mode of action (MOA) in mice have not been resolved, however. In the current work, a reanalysis of data from two chronic mouse cancer bioassays on 1,4-dioxane, one 13-week mouse study, seven rat cancer bioassays, coupled with other data such as 1,4-dioxane's negative mutagenicity, its lack of up-regulated DNA repair, and the appearance of liver tumors with a high background incidence, support the conclusion that rodent liver tumors, including those in mice, are evoked by a regenerative hyperplasia MOA...
March 30, 2017: Regulatory Toxicology and Pharmacology: RTP
Devika Poddalgoda, Kristin Macey, Henry Assad, Kannan Krishnan
The objectives of the present work were: (1) to assemble population-level biomonitoring data to identify the concentrations of urinary and plasma barium across the general population; and (2) to derive biomonitoring equivalents (BEs) for barium in urine and plasma in order to facilitate the interpretation of barium concentrations in the biological matrices. In population level biomonitoring studies, barium has been measured in urine in the U.S. (NHANES study), but no such data on plasma barium levels were identified...
March 27, 2017: Regulatory Toxicology and Pharmacology: RTP
Lu Chen, Patrick P J Mulder, Jochem Louisse, Ad Peijnenburg, Sebas Wesseling, Ivonne M C M Rietjens
Pyrrolizidine alkaloids (PAs) are plant metabolites present in some botanical preparations, with especially 1,2-unsaturated PAs being of concern because they are genotoxic carcinogens. This study presents an overview of tumour data on PAs and points of departure (PODs) derived from them, corroborating that the BMDL10 for lasiocarpine represents a conservative POD for risk assessment. A risk assessment using this BMDL10 and mean levels of PAs reported in literature for (herbal) teas, indicates that consumption of one cup of tea a day would result in MOE values lower than 10 000 for several types of (herbal) teas, indicating a priority for risk management for these products A refined risk assessment using interim relative potency (REP) factors showed that based on the mean PA levels, 7(54%) of 13 types of (herbal) teas and 1 (14%) of 7 types of plant food supplements (PFS) resulted in MOE values lower than 10 000, indicating a priority for risk management also for these products in particular...
March 27, 2017: Regulatory Toxicology and Pharmacology: RTP
Qiannan Zhang, Hui Yang, Yongning Li, Haibo Liu, Xudong Jia
Stevia rebaudiana Bertoni leaves have a long history of use as an abundant source of sweetener. The aqueous extract of stevia leaves and the predominant constitutes steviol glycosides have been intensively investigated. However, rare studies provided toxicological evaluation of bioactive components in the polar extract regarding their safety on human health. This study aimed to evaluate the toxicity of ethanolic extract of Stevia rebaudiana Bertoni leaves through a battery of in vitro and in vivo tests. Negative results were unanimously obtained from bacterial reverse mutation assay, mouse bone marrow micronucleus assay and mouse sperm malformation assay...
March 25, 2017: Regulatory Toxicology and Pharmacology: RTP
Paul M Whalley, Michael Bartels, Karin S Bentley, Marco Corvaro, Dorothee Funk, Matthew W Himmelstein, Birgit Neumann, Christian Strupp, Fagen Zhang, Jyotigna Mehta
The metabolism and elimination of a xenobiotic has a direct bearing on its potential to cause toxicity in an organism. The confidence with which data from safety studies can be extrapolated to humans depends, among other factors, upon knowing whether humans are systemically exposed to the same chemical entities (i.e. a parent compound and its metabolites) as the laboratory animals used to study toxicity. Ideally, to understand a metabolite in terms of safety, both the chemical structure and the systemic exposure would need to be determined...
March 24, 2017: Regulatory Toxicology and Pharmacology: RTP
Arne Burzlaff, Carol Beevers, Helen Pearce, Melvyn Lloyd, Kevin Klipsch
The potential of molybdenum substances to cause genotoxic effects has been studied previously. However, a review of existing in vitro data, including an assessment of relevance and reliability, has shown that inconsistent results have been observed in the past. To resolve the inconsistencies, new studies were performed with the highly soluble sodium molybdate dihydrate according to OECD test guidelines. In a bacterial reverse mutation assay sodium molybdate dihydrate did not induce reverse mutations in five strains of Salmonella typhimurium...
March 23, 2017: Regulatory Toxicology and Pharmacology: RTP
Diana Isela Araujo-Espino, Ana Lourdes Zamora-Perez, Guillermo Moisés Zúñiga-González, Rosalinda Gutiérrez-Hernández, Gabriela Morales-Velazquez, Blanca Patricia Lazalde-Ramos
Jatropha dioica Sessé ex Cerv. is a medicinal plant credited with low cytotoxicity in vitro. Thus, the objective of this work was to evaluate the possible genotoxic and cytotoxic effect in vivo of the J. dioica aqueous extract by means of micronucleus assay in mouse peripheral blood. Four different J. dioica aqueous extract dose-units were evaluated (30, 60, 100, and 300 mg/kg). The extract was administered orally to male Balb-C-strain mice every 24 h during 5 days. Blood samples were taken at 0, 24, 48, 72, 96, and 120 h from the mouse's tail and were performed in duplicate extensions...
March 23, 2017: Regulatory Toxicology and Pharmacology: RTP
Andrew Hill, Oscar M Camacho
In 2012 the US FDA suggested the use of mathematical models to assess the impact of releasing new nicotine or tobacco products on population health outcomes. A model based on system dynamics methodology was developed to project the potential effects of a new nicotine product at a population level. A model representing traditional smoking populations (never, current and former smokers) and calibrated using historical data was extended to a two-product model by including electronic cigarettes use statuses. Smoking mechanisms, such as product initiation, switching, transition to dual use, and cessation, were represented as flows between smoking statuses (stocks) and the potential effect of smoking renormalisation through a feedback system...
March 22, 2017: Regulatory Toxicology and Pharmacology: RTP
Brett J West
No abstract text is available yet for this article.
March 22, 2017: Regulatory Toxicology and Pharmacology: RTP
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