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Regulatory Toxicology and Pharmacology: RTP

Brian J Hughes, Kevin Cox, Virunya Bhat
Di 2-ethylhexyl cyclohexane-1,4-dicarboxylate (DEHCH, CAS 84731-70-4) is an ester of polycarboxylic acid assessed in a wide variety of ecotoxicological and mammalian toxicity assays as a substitute for phthalate ester-type plasticizers. Laboratory animal data indicate that DEHCH has a low acute oral and dermal toxicity, is non-irritating to the skin and eyes, and is a non-sensitizer. In an OECD 422 combined repeat dose toxicity study with a reproductive/developmental toxicity screening test in Sprague-Dawley rats, minimal effects were observed on the liver, spleen, and thyroid...
November 18, 2017: Regulatory Toxicology and Pharmacology: RTP
Yasunori Takahashi, Yuki Kanemaru, Toshiro Fukushima, Kentaro Eguchi, Shinya Yoshida, Jacqueline Miller-Holt, Ian Jones
The recent rapid increase in the prevalence of emerging tobacco- and nicotine-containing products, such as e-cigarettes, is being driven in part by their reduced-risk potential compared to tobacco smoking. In this study, we examined emission levels for selected cigarette smoke constituents, so-called "Hoffmann analytes", and in vitro toxicity of aerosol from a novel tobacco vapor product (NTV). The NTV thermally vaporizes a nicotine-free carrier liquid to form an aerosol which then passes through tobacco, where it absorbs tobacco-derived flavors and nicotine...
November 17, 2017: Regulatory Toxicology and Pharmacology: RTP
Kenneth A Mundt, P Robinan Gentry, Linda D Dell, Joseph V Rodricks, Paolo Boffetta
Shortly after the International Agency for Research on Cancer (IARC) determined that formaldehyde causes leukemia, the United States Environmental Protection Agency (EPA) released its Draft IRIS Toxicological Review of Formaldehyde, also concluding that formaldehyde causes leukemia. Peer review of the EPA Draft IRIS Assessment by a National Academy of Science committee noted that "causal determinations are not supported by the narrative provided in the draft" {NRC 2011}. They offered recommendations for improving the IRIS review and identified several important research gaps...
November 17, 2017: Regulatory Toxicology and Pharmacology: RTP
Joseph T Haney, Darrell McCant, Michael E Honeycutt, Sabine Lange
An inhalation reference concentration (RfC) was developed for diethanolamine (DEA), based principally on evaluation of three animal studies (Gamer et al., 1993, 1996, 2008). The RfC (25 μg/m(3)) was based on statistically significantly increased relative liver weight in female rats in Gamer et al. (2008) as the critical effect. The lower confidence limit on the benchmark dose (BMDL10 of 5.5 mg/m(3)) was adjusted to a human equivalent concentration and to continuous exposure before dividing the final point of departure (2...
November 17, 2017: Regulatory Toxicology and Pharmacology: RTP
Sang-Jin Park, JeongHo Noh, Eun Ju Jeong, Yong-Soon Kim, Byung-Cheol Han, Seung-Ho Lee, Kyoung-Sik Moon
Ginseng is a major herbal remedy used in Asian countries for thousands of years and known to restore and enhance vital energy. Korean red ginseng, which is processed by steaming and drying fresh Panax ginseng, is most popular and contains unique ginsenosides, which have anticancer and anti-inflammatory properties. The present study was carried out to evaluate the repeated oral dose toxicity of Korean red ginseng extract. The test article was administered orally once a day to male and female Sprague-Dawley rats at dose levels of 0, 500, 1000, or 2000 mg/kg/day for 13 consecutive weeks (15 animals/sex/group in the vehicle control and 2000 mg/kg/day groups, and 10 animals/sex/group in the 500 and 1000 mg/kg/day groups)...
November 16, 2017: Regulatory Toxicology and Pharmacology: RTP
Cheng-Tien Wu, Chen-Yuan Chiu, Chun-Fa Huang, Fu-Chuo Peng, Shing-Hwa Liu
Steady-fiber granule (SFG) is a functional food mixture that is composed of four major ingredients, resistant maltodextrin, white kidney bean (Phaseolus vulgaris) extract, mulberry leaf (Morus alba L.) extract, and niacin-bound chromium complex. This study focused on determining the safety of SFG. Genotoxicity and 28-day oral toxicity were evaluated. SFG did not induce mutagenicity in the bacterial reverse mutation assay using five Salmonella typhimurium strains (TA98, TA100, TA102, TA1535, and TA1537) in the presence or absence of metabolic activation (S9 system)...
November 16, 2017: Regulatory Toxicology and Pharmacology: RTP
Xiju He, Shoutian Li, Xiaoxia Fang, Yanhong Liao
TDCPP, Tris (1, 3-dichloro-2-propyl) phosphate belongs to a group of chemicals known as triester organophosphate flame retardants, It can alter calcium homeostasis at much lower concentrations in normal conditions, but the mechanism is unclear till now. Calcium overload is a leading cause of apoptosis in myocardial ischemia/reperfusion (I/R) injury, thus how to mitigate Ca(2+)-overload is deserved to be investigated. We therefore hypothesized that TDCPP could attenuate cardiomyocytes apoptosis in I/R injury...
November 9, 2017: Regulatory Toxicology and Pharmacology: RTP
Natássia Caroline Resende Corrêa, Crisciele Kuligovski, Ariane Caroline Campos Paschoal, Ana Paula Ressetti Abud, Carmen Lucia Kuniyoshi Rebelatto, Lidiane Maria Boldrini Leite, Alexandra Cristina Senegaglia, Bruno Dallagiovanna, Alessandra Melo de Aguiar
With the increasing need to develop in vitro assays to replace animal use, human stem cell-derived methods are emerging and showing outstanding contributions to the toxicological screening of substances. Adult human stem cells such as adipose-derived stem cells (ADSC) and periodontal ligament stem cells (PDLSC) were used as cell substrates for a cytotoxicity assay and toxicity prediction using the neutral red uptake (NRU) assay. First, primary cell cultures from three independent donors, from each tissue source, were characterized as mesenchymal stem cells (MSC) by plastic adherence and appropriate immunophenotype for MSC markers (positive for CD90, CD73, and CD105 and negative for CD11b, CD34, CD45, HLADR, and CD19)...
November 9, 2017: Regulatory Toxicology and Pharmacology: RTP
John W Caraway, Madeleine Ashley, Sheri A Bowman, Peter Chen, Graham Errington, Krishna Prasad, Paul R Nelson, Christopher J Shepperd, Ian M Fearon
Cigarette filter ventilation allows air to be drawn into the filter, diluting the cigarette smoke. Although machine smoking reveals that toxicant yields are reduced, it does not predict human yields. The objective of this study was to investigate the relationship between cigarette filter ventilation and mouth level exposure (MLE) to tar and nicotine in cigarette smokers. We collated and reviewed data from 11 studies across 9 countries, in studies performed between 2005 and 2013 which contained data on MLE from 156 products with filter ventilation between 0% and 87%...
November 8, 2017: Regulatory Toxicology and Pharmacology: RTP
Susan P Felter, Jennifer E Foreman, Alan Boobis, J Christopher Corton, Adriana M Doi, Lynn Flowers, Jay Goodman, Lynne T Haber, Abigail Jacobs, James E Klaunig, Angela M Lynch, Jonathan Moggs, Arun Pandiri
The Toxicology Forum sponsored a workshop in October 2016, on the human relevance of rodent liver tumors occurring via nongenotoxic modes of action (MOAs). The workshop focused on two nuclear receptor-mediated MOAs (Constitutive Androstane Receptor (CAR) and Peroxisome Proliferator Activated Receptor-alpha (PPARα), and on cytotoxicity. The goal of the meeting was to review the state of the science to (1) identify areas of consensus and differences, data gaps and research needs; (2) identify reasons for inconsistencies in current regulatory positions; and (3) consider what data are needed to demonstrate a specific MOA, and when additional research is needed to rule out alternative possibilities...
November 4, 2017: Regulatory Toxicology and Pharmacology: RTP
Lesa L Aylward, Kim Irwin, Annie St-Amand, Andy Nong, Sean M Hays
3-Phenoxybenzoic acid (3-PBA) is a common metabolite of several pyrethroid pesticides of differing potency and also occurs as a residue in foods resulting from environmental degradation of parent pyrethroid compounds. Thus, 3-PBA in urine is not a specific biomarker of exposure to a particular pyrethroid. However, an approach derived from the use of Biomonitoring Equivalents (BEs) can be used to estimate a conservative initial screening value for a tiered assessment of population data on 3-PBA in urine. A conservative generic urinary excretion fraction for 3-PBA was estimated from data for five pyrethroid compounds with human data...
November 4, 2017: Regulatory Toxicology and Pharmacology: RTP
Timothy W Gant, Ursula G Sauer, Shu-Dong Zhang, Brian N Chorley, Jörg Hackermüller, Stefania Perdichizzi, Knut E Tollefsen, Ben van Ravenzwaay, Carole Yauk, Weida Tong, Alan Poole
A generic Transcriptomics Reporting Framework (TRF) is presented that lists parameters that should be reported in 'omics studies used in a regulatory context. The TRF encompasses the processes from transcriptome profiling from data generation to a processed list of differentially expressed genes (DEGs) ready for interpretation. Included within the TRF is a reference baseline analysis (RBA) that encompasses raw data selection; data normalisation; recognition of outliers; and statistical analysis. The TRF itself does not dictate the methodology for data processing, but deals with what should be reported...
November 4, 2017: Regulatory Toxicology and Pharmacology: RTP
Jun-Won Yun, Seung-Hyun Kim, Yun-Soon Kim, Ji-Ran You, Eun-Young Cho, Jung-Hee Yoon, Euna Kwon, In-Jue Yun, Je-Hun Oh, Ja-June Jang, Jin-Sung Park, Jeong-Hwan Che, Byeong-Cheol Kang
Ecklonia cava (EC) is known to have antioxidant, anti-inflammatory, antidiabetic, and anticancer properties. Despite its wide use and beneficial properties, comprehensive toxicological information regarding EC extract is currently limited. Therefore, the purpose of this study was to investigate acute toxicity, subchronic toxicity, and genotoxicity of enzymatic EC extract according to test guidelines published by Organization for Economic Cooperation and Development. The acute oral LD50 values of this EC extract administered to rats and dogs were estimated to be more than 3000 mg/kg BW...
November 3, 2017: Regulatory Toxicology and Pharmacology: RTP
Anjna Sharma, Asmita Magotra, Ashish Dogra, Santosh Kumar Rath, Sheikh Rayees, Priya Wazir, Sadhana Sharma, Payare Lal Sangwan, Surjeet Singh, Gurdarshan Singh, Utpal Nandi
In spite of unprecedented advances in modern systems of medicine, there is necessity for exploration of traditional plant based secondary metabolites or their semisynthetic derivatives which may results in better therapeutic activity, low toxicity and favourable pharmacokinetics. In this context, computational model based predictions aid medicinal chemists in rational development of new chemical entity having unfavourable pharmacokinetic properties which is a major hurdle for its further development as a drug molecule...
November 3, 2017: Regulatory Toxicology and Pharmacology: RTP
Hira Choudhury, Bapi Gorain, Rakesh Kumar Tekade, Manisha Pandey, Sanmoy Karmakar, Tapan Kumar Pal
Oral paclitaxel (PTXL) formulations freed from cremophor(®) EL (CrEL) is always in utmost demand by the cancerous patients due to toxicities associated with the currently marketed formulation. In our previous investigation [Int. J. Pharm. 2014; 460:131], we have developed an oral oil based nanocarrier for the lipophilic drug, PTXL to target bioavailability issue and patient compliance. Here, we report in vivo antitumor activity and 28-day sub-chronic toxicity of the developed PTXL nanoemulsion. It was observed that the apoptotic potential of oral PTXL nanoemulsion significantly inhibited the growth of solid tumor (59...
November 3, 2017: Regulatory Toxicology and Pharmacology: RTP
Helga Rothe, Cindy A Ryan, Leanne Page, Joanne Vinall, Carsten Goebel, Heike Scheffler, Frank Toner, Clive Roper, Petra S Kern
Use of quantitative risk assessment (QRA) for assessing the skin sensitization potential of chemicals present in consumer products requires an understanding of hazard and product exposure. In the absence of data, consumer exposure is based on relevant habits and practices and assumes 100% skin uptake of the applied dose. To confirm and refine the exposure, a novel design for in vitro skin exposure measurements was conducted with the preservative, methylisothiazolinone (MI), in beauty care (BC) and household care (HHC) products using realistic consumer exposure conditions...
November 3, 2017: Regulatory Toxicology and Pharmacology: RTP
Xuezhang Chen, Qixi Deng, Shubao Lin, Chao Du, Shengqiao Zhao, Yongjie Hu, Zhongguo Yang, Yanhui Lyu, Jianjian Han
A semi-quantitative risk assessment of banned azo dyes in textiles was performed to assess the health risk when consumers have direct dermal contact with these products. A novel model, which includes three exposure scenarios, was proposed to estimate the absorption of leachable azo dyes from twenty textiles samples. The effective daily uptakes of benzidine from sample 1 and sample 19 in chronic exposure model were 0.318 ng/kg-day and 0.011 ng/kg-day, respectively. Compared to virtually safe dose (VSD), the corresponding cancer risks were 7...
November 2, 2017: Regulatory Toxicology and Pharmacology: RTP
Tooraj Vakili, Mehrdad Iranshahi, Hosseinali Arab, Bamdad Riahi, Nama Mohammadian Roshan, Gholamreza Karimi
Auraptene (AUR) is a natural, bioactive, monoterpene coumarin ether. It has anti-inflammatory, anti-carcinogenic, anti-bacterial, neuroprotective, and hepatoprotective properties. The aim of the present study was to assess the acute and subacute toxicity of oral administration of AUR in rats by evaluating clinical signs, haematology, biochemical factors, pathological changes and immune-toxicity. Acute administration of AUR in doses of 125, 250, 500, 1000 and 2000 mg/kg body weight had no mortality or clinical signs in a period of two days...
November 1, 2017: Regulatory Toxicology and Pharmacology: RTP
Patrick Poulin, Richard Arnett
The objective was to challenge cross-species extrapolation factors with which to scale animal doses to human by any route for non-carcinogenic endpoints. The conventional hypothesis of the toxicokinetics (TK)-toxicodynamics (TD) relationship was equal toxicity at equal plasma level of the total drug moiety in each species, but this should also follow the free drug assumption, which states that only the unbound drug moiety in plasma may elicit a TD effect in tissue. Therefore, a protein binding factor (PBF) was combined with the Chemical-Specific Adjustment Factor (CSAF) (i...
October 31, 2017: Regulatory Toxicology and Pharmacology: RTP
Heather R Schaefer, Jessica L Myers
The Texas Commission on Environmental Quality (TCEQ) developed guidance on conducting systematic reviews during the development of chemical-specific toxicity factors. Using elements from publicly available frameworks, the TCEQ systematic review process was developed in order to supplement the existing TCEQ Guidelines for developing toxicity factors (TCEQ Regulatory Guidance 442). The TCEQ systematic review process includes six steps: 1) Problem Formulation; 2) Systematic Literature Review and Study Selection; 3) Data Extraction; 4) Study Quality and Risk of Bias Assessment; 5) Evidence Integration and Endpoint Determination; and 6) Confidence Rating...
October 31, 2017: Regulatory Toxicology and Pharmacology: RTP
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