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Fares F, Khatib S, Vaya J, Sharvit L, Eizenberg E, Wasser S. Striatal Isolated from Cyathus striatus Extracts Induces Apoptosis in Human Pancreatic Cancer Cells. Molecules 2022; 27:2746. [PMID: 35566094 PMCID: PMC9103111 DOI: 10.3390/molecules27092746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 12/10/2022] Open
Abstract
The aim of the present study was to identify the structure of active compounds in Cyathus stratus that previously demonstrated anti-pancreatic cancer activity. The active compounds were purified from a crude extract by a series of RP-18 preparative chromatography using homemade octadecyl silica gel column. HPLC injection of the crude extract revealed a chromatogram with three main peaks with retention times (RT) 15.6, 18.2, and 22.5 min. Each fraction that exhibited promising activity in vitro was further separated using various available chromatographic techniques. The purified compound with the ultimate anti-cancer activity appeared at RT of 15.8 in the HPLC chromatogram with more than 90% purity. The main peak at the mass spectra appeared at m/z = 446.2304 with the calculated molecular formula of C25H34O7. One- and two-dimensional NMR analyses indicated that the structure of the active molecule (peak 15.8 min in HPLC) was identified as striatal C. Exposure of human pancreatic cancer cells to purified striatal C resulted in induction of apoptosis. Further studies are needed in order to develop a method for the synthesis of striatal in order to use it in clinical studies for treatment of cancer.
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Affiliation(s)
- Fuad Fares
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel; (L.S.); (E.E.)
| | - Soliman Khatib
- Laboratory of Natural Compounds and Analytical Chemistry, MIGAL Galilee Research Institute, Kiryat Shmona 11016, Israel; (S.K.); (J.V.)
- Tel-Hai College, Tel-Hai 1220800, Israel
| | - Jacob Vaya
- Laboratory of Natural Compounds and Analytical Chemistry, MIGAL Galilee Research Institute, Kiryat Shmona 11016, Israel; (S.K.); (J.V.)
| | - Lital Sharvit
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel; (L.S.); (E.E.)
| | - Einav Eizenberg
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel; (L.S.); (E.E.)
| | - Solomon Wasser
- Institute of Evolution and Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel;
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What Are the Real Causes of Cancer? INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2013. [DOI: 10.1179/oeh.2006.12.1.81] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Huff J, Ladou L. Aspartame Bioassay Findings Portend Human Cancer Hazards. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2013; 13:446-8. [DOI: 10.1179/oeh.2007.13.4.446] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Ladou J, Teitelbaum DT, Egilman DS, Frank AL, Kramer SN, Huff J. American College of Occupational and Environmental Medicine (ACOEM): A Professional Association in Service to Industry. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2013; 13:404-26. [DOI: 10.1179/oeh.2007.13.4.404] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Benigni R, Bossa C, Tcheremenskaia O. Nongenotoxic carcinogenicity of chemicals: mechanisms of action and early recognition through a new set of structural alerts. Chem Rev 2013; 113:2940-57. [PMID: 23469814 DOI: 10.1021/cr300206t] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Romualdo Benigni
- Istituto Superiore di Sanita' Environment and Health Department, Viale Regina Elena 299, 00161 Rome, Italy.
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Benigni R, Bossa C, Tcheremenskaia O. In vitro cell transformation assays for an integrated, alternative assessment of carcinogenicity: a data-based analysis. Mutagenesis 2012; 28:107-16. [DOI: 10.1093/mutage/ges059] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Huff J. Long-term toxicology and carcinogenicity of 2,4,6-trichlorophenol. CHEMOSPHERE 2012; 89:521-525. [PMID: 22748215 DOI: 10.1016/j.chemosphere.2012.05.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/13/2012] [Accepted: 05/04/2012] [Indexed: 06/01/2023]
Abstract
Carcinogenesis bioassays were conducted by giving 2,4,6-trichlorophenol [2,4,6-TCP] in feed to groups of 50 male and female Fischer rats and male B6C3F1 mice for two years. Dietary concentrations were 0 [20/group], 5000 [0.5%], or 10,000 [1%] ppm. Female mice began with 10,000 and 20,000 ppm but after 38 weeks were lowered due to reduced body weights to 2500 and 5000 ppm for 67 weeks; exposures averaged 5200 and 10,400 ppm. Adverse effects at two years were leukocytosis and monocytosis of peripheral blood and hyperplasia of bone marrow in both sexes of rats. In mice, liver toxicity, including individual liver cell abnormalities, focal areas of cellular alteration, and focal and nodular areas of hyperplasia were commonly present. Regarding carcinogenic activity, TCP caused leukemias/lymphomas in male rats, and possibly in female rats and female mice as well, and induced liver tumors in male and female mice. Using NTP categories of evidence indicates 'clear evidence of carcinogenicity' for male rats [hematopoietic system tumors]; 'equivocal evidence of carcinogenicity' for female rats [hematopoietic system tumors]; 'clear evidence of carcinogenicity' for male and female mice [liver tumors].
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Affiliation(s)
- James Huff
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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Awadelkarim KD, Mariani-Costantini R, Elwali NE. Cancer in the Sudan: an overview of the current status of knowledge on tumor patterns and risk factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 423:214-28. [PMID: 21071068 DOI: 10.1016/j.scitotenv.2010.09.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 09/06/2010] [Accepted: 09/07/2010] [Indexed: 05/21/2023]
Abstract
The Sudan, the largest and most diverse country in Africa, is experiencing a growing cancer problem, but little is presently known on tumor patterns, cancer epidemiology and ethnic or environmental cancer risk factors. We review here the current status of knowledge, summarizing data from local and international publications as well as primary information from the only two cancer hospitals of the country, both located in Central Sudan (Khartoum and Wad Medani). We provide frequencies reported for cancers detected in adults and children, and summarize studies on specific cancer types, as well as information on risk factors that most likely impact on tumor patterns.
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Huff J, Melnick R. Environmental justice and primary prevention of cancer: the odyssey and legacy of lorenzo tomatis. New Solut 2012; 22:7-17. [PMID: 22436205 DOI: 10.2190/ns.22.1.b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lorenzo Tomatis [1929-2007] devoted his private and professional life to the betterment of mankind. As a physician, scientist, and humanitarian he championed against the plight of social injustice and promoted the obvious benefits of primary prevention of diseases compared to treatments that prevent or delay disease progression, especially occupational cancers. An avowed student and scholar of literature, the arts, the history of medicine and science, and chemical carcinogenesis, he believed in and wrote about these issues throughout his storied life. Some of his achievements, with excerpts from his writings, especially on primary prevention and on social injustice, are highlighted herein.
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Affiliation(s)
- James Huff
- NIEHS, P.O. Box 12233, Research Triangle Park, NC 27709, USA.
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Benigni R. Alternatives to the carcinogenicity bioassay for toxicity prediction: are we there yet? Expert Opin Drug Metab Toxicol 2012; 8:407-17. [PMID: 22360376 DOI: 10.1517/17425255.2012.666238] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION For decades, traditional toxicology has been the ultimate source of information on the carcinogenic potential of chemicals; however, with increasing demand on regulation of chemicals and decreasing resources for testing, opportunities to accept 'alternative' approaches have dramatically expanded. The need for tools able to identify carcinogens in shorter times and at a lower cost in terms of animal lives and money is still an open issue, and the present strategies and regulations for carcinogenicity prescreening do not adequately protect human health. AREAS COVERED This paper briefly summarizes the theories on the early steps of carcinogenesis and presents alternative detection methods for carcinogens based on genetic toxicology, structure-activity relationships and cell transformation assays. EXPERT OPINION There is evidence that the combination of Salmonella and structural alerts for the DNA-reactive carcinogens, and in vitro cell transformation assays for nongenotoxic carcinogens, permits the identification of a very large proportion of carcinogens. If implemented, this alternative strategy could improve considerably the protection of human health.
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Affiliation(s)
- Romualdo Benigni
- Environment and Health Department, Istituto Superiore di Sanita, Viale Regina Elena 299 00161, Rome, Italy.
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Abstract
Styrene is widely used in the manufacture of synthetic rubber, resins, polyesters and plastics. Styrene and the primary metabolite styrene-7,8-oxide are genotoxic and carcinogenic. Long-term chemical carcinogenesis bioassays showed that styrene caused lung cancers in several strains of mice and mammary cancers in rats and styrene-7,8-oxide caused tumours of the forestomach in rats and mice and of the liver in mice. Subsequent epidemiologic studies found styrene workers had increased mortality or incidences of lymphohematopoietic cancers (leukaemia or lymphoma or all), with suggestive evidence for pancreatic and esophageal tumours. No adequate human studies are available for styrene-7,8-oxide although this is the primary and active epoxide metabolite of styrene. Both are genotoxic and form DNA adducts in humans.
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Affiliation(s)
- James Huff
- National Institute of Environmental Health Sciences, Research Triangle Park, 111 T.W.Alexander Drive, NC 27709, USA.
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Affiliation(s)
- James Huff
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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Abstract
The leading 20th century proponent for primary prevention of environmental cancer was Dr. Lorenzo Tomatis, the former Director of the International Agency for Research on Cancer and founder of the IARC Monographs program. This paper is dedicated to the memory of Dr. Tomatis--eminent scientist, scholar, teacher, humanitarian, and public health champion--and includes many perspectives that he promoted throughout his career, with original quotations from some of his scientific writings on primary prevention of environmental cancer. Any attempt by us to simply summarize his views would only detract from the power and logic of his language."Cancer still remains a mainly lethal disease. Primary prevention remains the most relevant approach to reduce mortality through a reduction in incidence".
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Affiliation(s)
- Ronald L Melnick
- Ron Melnick Consulting, LLC, 111 Roundtree Rd, Chapel Hill, NC 25514, USA
| | - James Huff
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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Huff J, Chan P, Melnick R. Clarifying carcinogenicity of ethylbenzene. Regul Toxicol Pharmacol 2010; 58:167-9; discussion 170-2. [PMID: 20723573 PMCID: PMC2989615 DOI: 10.1016/j.yrtph.2010.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 08/08/2010] [Indexed: 11/18/2022]
Abstract
Ethylbenzene has been evaluated for carcinogenic activity in Fischer rats and B6C3F1 mice exposed by inhalation (Chan et al., 1998; Chan, 1999) and in Sprague-Dawley rats after oral exposure (Maltoni et al., 1985,1997). Bioassay findings are summarized below to expand on those not stated clearly or completely in Saghir et al. (2010). Overall in these three studies animals exposed to ethylbenzene had increased tumors in rats for kidneys, testes, head (including rare neuroesthesioepitheliomas), and total malignant tumors, whilst in mice tumor incidences were increased in the lung and liver (Huff, 2002). Thus ethylbenzene was carcinogenic by two exposure routes to both sexes of two species of rodents, two strains of rats, and one strain of mice, causing collectively tumors in five different target organs and a composite of "total malignant" tumors.
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Affiliation(s)
- James Huff
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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Hogervorst JGF, Baars BJ, Schouten LJ, Konings EJM, Goldbohm RA, van den Brandt PA. The carcinogenicity of dietary acrylamide intake: a comparative discussion of epidemiological and experimental animal research. Crit Rev Toxicol 2010; 40:485-512. [PMID: 20170357 DOI: 10.3109/10408440903524254] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Since 2002, it is known that the probable human carcinogen acrylamide is present in commonly consumed carbohydrate-rich foods, such as French fries and potato chips. In this review, the authors discuss the body of evidence on acrylamide carcinogenicity from both epidemiological and rodent studies, including variability, strengths and weaknesses, how both types of evidence relate, and possible reasons for discrepancies. In both rats and humans, increased incidences of various cancer types were observed. In rats, increased incidences of mammary gland, thyroid tumors and scrotal mesothelioma were observed in both studies that were performed. In humans, increased risks of ovarian and endometrial cancers, renal cell cancer, estrogen (and progesterone) receptor-positive breast cancer, and oral cavity cancer (the latter in non-smoking women) were observed. Some cancer types were found in both rats and humans, e.g., endometrial cancer (observed in one of the two rat studies), but there are also some inconsistencies. Interestingly, in humans, some indications for inverse associations were observed for lung and bladder cancers in women, and prostate and oro- and hypopharynx cancers in men. These latter observations indicate that genotoxicity may not be the only mechanism by which acrylamide causes cancer. The estimated risks based on the epidemiological studies for the sites for which a positive association was observed were considerably higher than those based on extrapolations from the rat studies. The observed pattern of increased risks in the rat and epidemiological studies and the decreased risks in the epidemiological studies suggests that acrylamide might influence hormonal systems, for which rodents may not be good models.
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Affiliation(s)
- Janneke G F Hogervorst
- Department of Epidemiology, GROW-School for Oncology and Developmental Biology, Maastricht University, Maastricht, The Netherlands.
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Melnick RL, Thayer KA, Bucher JR. Conflicting views on chemical carcinogenesis arising from the design and evaluation of rodent carcinogenicity studies. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:130-5. [PMID: 18197312 PMCID: PMC2199296 DOI: 10.1289/ehp.9989] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 05/29/2007] [Indexed: 05/20/2023]
Abstract
Conflicting views have been expressed frequently on assessments of human cancer risk of environmental agents based on animal carcinogenicity data; this is primarily because of uncertainties associated with extrapolations of toxicologic findings from studies in experimental animals to human circumstances. Underlying these uncertainties are issues related to how experiments are designed, how rigorously hypotheses are tested, and to what extent assertions extend beyond actual findings. National and international health agencies regard carcinogenicity findings in well-conducted experimental animal studies as evidence of potential carcinogenic risk to humans. Controversies arise when both positive and negative carcinogenicity data exist for a specific agent or when incomplete mechanistic data suggest a possible species difference in response. Issues of experimental design and evaluation that might contribute to disparate results are addressed in this article. To serve as reliable sources of data for the evaluation of the carcinogenic potential of environmental agents, experimental studies must include a) animal models that are sensitive to the end points under investigation; b) detailed characterization of the agent and the administered doses; c) challenging doses and durations of exposure (at least 2 years for rats and mice); d) sufficient numbers of animals per dose group to be capable of detecting a true effect; e) multiple dose groups to allow characterization of dose-response relationships, f) complete and peer-reviewed histopathologic evaluations; and g) pairwise comparisons and analyses of trends based on survival-adjusted tumor incidence. Pharmacokinetic models and mechanistic hypotheses may provide insights into the biological behavior of the agent; however, they must be adequately tested before being used to evaluate human cancer risk.
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Affiliation(s)
- Ronald L Melnick
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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Huff J, Melnick R. In Memoriam: Lorenzo Tomatis 1929-2007. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:A16-A17. [PMID: 18197277 PMCID: PMC2199285 DOI: 10.1289/ehp.116-a16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Huff J. Benzene-induced cancers: abridged history and occupational health impact. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2007; 13:213-21. [PMID: 17718179 PMCID: PMC3363002 DOI: 10.1179/oeh.2007.13.2.213] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Benzene-induced cancer in humans was first reported in the late 1920s. Carcinogenesis findings in animals were not reported conclusively until 1979. Industry exploited this "discrepancy" to discredit the use of animal bioassays as surrogates for human exposure experience. The cardinal reason for the delay between first recognizing leukemia in humans and sought-after neoplasia in animals centers on poor design and conduct of experimental studies. The first evidence of carcinogenicity in animals manifested as malignant tumors of the zymbal glands (sebaceous glands in the ear canal) of rats, and industry attempted to discount this as being irrelevant to humans, as this organ is vestigial and not present per se in humans. Nonetheless, shortly thereafter benzene was shown to be carcinogenic to multiple organ sites in both sexes of multiple strains and multiple species of laboratory animals exposed via various routes. This paper presents a condensed history of the benzene bioassay story with mention of benzene-associated human cancers.
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Affiliation(s)
- James Huff
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27514, USA.
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Huff J, Lunn RM, Waalkes MP, Tomatis L, Infante PF. Cadmium-induced cancers in animals and in humans. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2007; 13:202-12. [PMID: 17718178 PMCID: PMC3399253 DOI: 10.1179/oeh.2007.13.2.202] [Citation(s) in RCA: 229] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Discovered in the early 1800s, the use of cadmium and various cadmium salts started to become industrially important near the close of the 19th century, rapidly thereafter began to flourish, yet has diminished more recently. Most cadmium used in the United States is a byproduct from the smelting of zinc, lead, or copper ores, and is used to manufacture batteries. Carcinogenic activity of cadmium was discovered first in animals and only subsequently in humans. Cadmium and cadmium compounds have been classified as known human carcinogens by the International Agency for Research on Cancer and the National Toxicology Program based on epidemiologic studies showing a causal association with lung cancer, and possibly prostate cancer, and studies in experimental animals, demonstrating that cadmium causes tumors at multiple tissue sites, by various routes of exposure, and in several species and strains. Epidemiologic studies published since these evaluations suggest that cadmium is also associated with cancers of the breast, kidney, pancreas, and urinary bladder. The basic metal cationic portion of cadmium is responsible for both toxic and carcinogenic activity, and the mechanism of carcinogenicity appears to be multifactorial. Available information about the carcinogenicity of cadmium and cadmium compounds is reviewed, evaluated, and discussed.
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Affiliation(s)
- James Huff
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27514, USA.
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Affiliation(s)
- Jerrold M. Ward
- Comparative Medicine Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health
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Abstract
During the annual Ramazzini Days, the Mayor of Carpi confers the Ramazzini Award on scientists deemed by the Collegium Ramazzini to have made outstanding contributions to furthering the aims of Bernardino Ramazzini in safeguarding public health. Dr. Lorenzo Tomatis was the Ramazzini Award recipient in 2005, and the presentation of the award was a highlight of the Symposium. The Ramazzini Lecture given by Dr. Tomatis follows.
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Affiliation(s)
- Lorenzo Tomatis
- International Society of Doctors for the Environment, Arezzo, Italy.
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Arthur JW, Sanchez-Perez A, Cook DI. Scoring of predicted GRK2 phosphorylation sites in Nedd4-2. Bioinformatics 2006; 22:2192-5. [PMID: 16844705 DOI: 10.1093/bioinformatics/btl381] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
MOTIVATION Epithelial Na(+) channels (ENaC) mediate the transport of sodium (Na) across epithelia in the kidney, gut and lungs and are required for blood pressure regulation. They are inhibited by ubiquitin protein ligases, such as Nedd4-2. These ligases bind to proline-rich motifs (PY motifs) present in the C-termini of ENaC subunits. Loss of this inhibition leads to hypertension. We have previously reported that ENaC channels are maintained in the active state by the G protein coupled receptor kinase, GRK2. The enzyme has been implicated in the development of essential hypertension [R. D. Feldman (2002) Mol. Pharmacol., 61, 707-709]. Additional findings in our lab pointed towards a possible role for GRK2 in the phosphorylation and inactivation of Nedd4-2. RESULTS We have predicted GRK2 phosphorylation sites on Nedd4-2 by combining sequence analysis, homology modeling and surface accessibility calculations. A total of 24 potential phosphorylation sites were predicted by sequence analysis. Of these, 16 could be modeled using homology modeling and 6 of these were found to have sufficient surface exposure to be accessible to the GRK2 enzyme responsible for the phosphorylation of Nedd4-2. The method provides an ordered list of the most probable GRK2 phosphorylation sites on Nedd4-2 providing invaluable guidance to future experimental studies aimed at mutating certain Nedd4-2 residues in order to prevent phosphorylation by GRK2. The method developed could be applied in a wide variety of biological applications involving the binding of one molecule to a protein. The relative effectiveness of the technique is determined mainly by the quality of the homology model built for the protein of interest. CONTACT jarthur@med.usyd.edu.au
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Magkos F, Arvaniti F, Zampelas A. Organic Food: Buying More Safety or Just Peace of Mind? A Critical Review of the Literature. Crit Rev Food Sci Nutr 2006; 46:23-56. [PMID: 16403682 DOI: 10.1080/10408690490911846] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Consumer concern over the quality and safety of conventional food has intensified in recent years, and primarily drives the increasing demand for organically grown food, which is perceived as healthier and safer. Relevant scientific evidence, however, is scarce, while anecdotal reports abound. Although there is an urgent need for information related to health benefits and/or hazards of food products of both origins, generalized conclusions remain tentative in the absence of adequate comparative data. Organic fruits and vegetables can be expected to contain fewer agrochemical residues than conventionally grown alternatives; yet, the significance of this difference is questionable, inasmuch as actual levels of contamination in both types of food are generally well below acceptable limits. Also, some leafy, root, and tuber organic vegetables appear to have lower nitrate content compared with conventional ones, but whether or not dietary nitrate indeed constitutes a threat to human health is a matter of debate. On the other hand, no differences can be identified for environmental contaminants (e.g. cadmium and other heavy metals), which are likely to be present in food from both origins. With respect to other food hazards, such as endogenous plant toxins, biological pesticides and pathogenic microorganisms, available evidence is extremely limited preventing generalized statements. Also, results for mycotoxin contamination in cereal crops are variable and inconclusive; hence, no clear picture emerges. It is difficult, therefore, to weigh the risks, but what should be made clear is that 'organic' does not automatically equal 'safe.' Additional studies in this area of research are warranted. At our present state of knowledge, other factors rather than safety aspects seem to speak in favor of organic food.
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Affiliation(s)
- Faidon Magkos
- Laboratory of Nutrition and Clinical Dietetics, Department of Nutrition and Dietetics, Harokopio University, 70 El. Venizelou Ave, Kallithea, Athens, 176 71, Greece
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Melnick RL. ADaubertMotion: A Legal Strategy to Exclude Essential Scientific Evidence in Toxic Tort Litigation. Am J Public Health 2005; 95 Suppl 1:S30-4. [PMID: 16030335 DOI: 10.2105/ajph.2004.046250] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
In the US Supreme Court's Daubert v Merrell Dow Pharmaceuticals, Inc decision, federal judges were directed to examine the scientific method underlying expert evidence and admit that which is scientifically reliable and relevant. However, if a judge does not have adequate training or experience in dealing with scientific uncertainty, understand the full value or limit of currently used methodologies, or recognize hidden assumptions, misrepresentations of scientific data, or the strengths of scientific inferences, he or she may reach an incorrect decision on the reliability and relevance of evidence linking environmental factors to human disease. This could lead to the unfair exclusion of valid scientific evidence, particularly that which is essential to a plaintiff's case in toxic tort litigation.
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Affiliation(s)
- Ronald L Melnick
- Environmental Toxicology Program, National Institute for Environmental Health Sciences, National Institutes of Health, Bethesda, MD, USA.
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Maronpot RR, Flake G, Huff J. Relevance of animal carcinogenesis findings to human cancer predictions and prevention. Toxicol Pathol 2004; 32 Suppl 1:40-8. [PMID: 15209402 DOI: 10.1080/01926230490425003] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Use of laboratory animals to identify carcinogenic potential of chemicals, mixtures, and other agents has a modern history of greater than 40 years from which much useful scientific and public health information can be derived. While laboratory animals differ from humans in some respects that may affect responses to hazardous exposures, use of such models is based on experimental evidence indicating that there are more genetic, genomic, physiological, biochemical, and metabolic similarities than differences among mammalian species. Issues of concordance of responses between rodent species and between rodents and humans as well as repeatability and site-specificity are important considerations in evaluating laboratory animal carcinogenicity results. Variables in experimental design such as animal strain, diet, route of exposure, and study, duration as well as single-site versus multisite carcinogenic responses all influence interpretation and intelligent use of study data. Similarities and differences in site-specific laboratory animal and corresponding human cancers should also be considered in study evaluation. Recent attempts to explore genetically engineered mice and to humanize the mouse for more relevant identification of carcinogen hazard identification have yielded mixed results. In the end we are confronted by the realization that virtually all animal cancer models are useful but imperfect surrogates for humans. Assuming the percentage of chemicals currently in commerce that are estimated to be potent animal or human carcinogens is quite low, the task of identifying agents with significant carcinogenic potential is daunting and important. The biological conundrum of scientific debate regarding the relevance of carcinogenicity studies in laboratory animals is likely to continue. Nonetheless public health considerations must take precedence when deciding human safety issues.
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Affiliation(s)
- R R Maronpot
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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Huff J. Chemicals studied and evaluated in long-term carcinogenesis bioassays by both the Ramazzini Foundation and the National Toxicology Program: in tribute to Cesare Maltoni and David Rall. Ann N Y Acad Sci 2002; 982:208-30. [PMID: 12562639 DOI: 10.1111/j.1749-6632.2002.tb04935.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Ramazzini Foundation (RF) in Bentivoglio, Italy and the National Toxicology Program (NTP) in Research Triangle Park, North Carolina have carried out several hundred chemical carcinogenesis bioassays: 200 by RF and 500 by NTP. Of these, 21 have been evaluated by both laboratories. The 14 chemicals for which both laboratories have designed, conducted, and reported bioassay results are: acrylonitrile, benzene, chlorine, diesel fuel, ethylbenzene, methylene chloride (dichloromethane), propylene, styrene, styrene oxide, toluene, trichloroethylene, trichlorofluoromethane, vinylidene chloride, and xylenes. The other seven chemicals (two are fibers) were evaluated by both laboratories, but results have not yet been published. Results of these 14 interlaboratory studies were compared both to explore consistency of carcinogenic responses and to identify possible factors that may reveal reasons for any differences observed. Individual carcinogenesis results from each laboratory were duplicated and complementary. Of the 14 chemicals compared, 11 (80%) were either carcinogenic (9 chemicals) or noncarcinogenic (2 chemicals) in both studies. Eight of the paired chemicals had at least one carcinogenic target site in common. The other three were carcinogenic in one laboratory but not in the other. Possible explanations for these differences include dose, method of administration, duration of follow-up, and whether or not total tumors are counted. The collaboration between these two pioneering bioassay laboratory programs contributes greatly to our understanding of chemical carcinogenesis and results in better protection of workers and the general population from chemical diseases, especially cancers.
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Affiliation(s)
- James Huff
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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Johnson FM. How many food additives are rodent carcinogens? ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2002; 39:69-80. [PMID: 11813298 DOI: 10.1002/em.10037] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
One generally assumes that chemical agents added to foods are reasonably free of risks to human health, and practically everyone consumes some additives in his or her food daily throughout life. In the United States, the 1958 Food Additives Amendment to the Federal Food, Drug and Cosmetic Act of 1938 requires food manufacturers to demonstrate the safety of food additives to the Food and Drug Administration (FDA). The Amendment contains a provision that prohibits approval of an additive if it is found to cause cancer in humans or animals. In the present study, data from the National Toxicology Program rodent bioassay (NTPRB) were used to identify a sample of approximately 50 rodent-tested additives and other chemicals added to food that had been evaluated independently of the FDA/food industry. Surprisingly, the sample shows more than 40% of these food chemicals to be carcinogenic in one or more rodent groups. If this percentage is extrapolated to all substances added to food in the United States, it would imply that more than 1000 of such substances are potential rodent carcinogens. The NTP and FDA test guidelines use similar, though not necessarily identical, rodent test procedures, including near lifetime exposures to the maximum tolerated dose. The FDA specifies that test chemicals should be administered by the oral route. However, the oral route includes three methods of delivering chemicals, that is, mixed in the food or water or delivered by stomach tube (gavage). The NTP data show only 1 of 18 food chemicals mixed in the food are rodent carcinogens, but 16 of 23 gavage-administered food chemicals are carcinogenic to rodents. The distribution suggests that among orally delivered chemicals, those administered in the feed will more likely prove to be noncarcinogens than chemicals given by gavage. The rodent data also reveal that effects may vary according to dose and genotype, as well as by route of administration, to further complicate extrapolation to humans. Human experience with known carcinogens such as tobacco, asbestos, and benzidine convinces us that environmental carcinogens constitute a real threat to human health, although predicting human carcinogens from rodent tests involves a number of uncertainties. These uncertainties do not mean that we should simply ignore the presence of carcinogens. Rather, in the interests of public safety, a serious effort should be made to resolve the questions surrounding the presence of chemicals identified as rodent carcinogens in our food. Environ. Mol. Mutagen. 39:69-80, 2002 Published 2002 Wiley-Liss, Inc.
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Affiliation(s)
- F M Johnson
- Toxicology Operations Branch, Environmental Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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Boorman GA, Haseman JK, Waters MD, Hardisty JF, Sills RC. Quality review procedures necessary for rodent pathology databases and toxicogenomic studies: the National Toxicology Program experience. Toxicol Pathol 2002; 30:88-92. [PMID: 11890481 DOI: 10.1080/01926230252824752] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Accuracy of the pathology data is crucial since rodent studies often provide critical data used for setting human chemical exposure standards. Diagnoses represent a judgment on the expected biological behavior of a lesion and peer review can improve diagnostic accuracy and consistency. With the conduct of 500 2-year rodent studies, the National Toxicology Program (NTP) has refined its process for comprehensive review of the pathology data and diagnoses. We have found that careful judgment can improve and simplify the review, whereas simply applying a set review procedure may not assure study quality. The use of reviewing pathologists and pathology peer review groups is a very effective procedure to increase study quality with minimal time and cost. New genomic technology to assess differential gene expression is being used to predict morphological phenotypes such as necrosis, hyperplasia, and neoplasia. The challenge for pathologists is to provide uniform pathology phenotypes that can be correlated with the gene expression changes. The lessons learned in assuring data quality in standard rodent studies also applies to the emerging field of toxicogenomics.
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Affiliation(s)
- Gary A Boorman
- Laboratory for Experimental Pathology, Environmental Toxicology Program, National Center for Toxicogenomics, NIEHS, Research Triangle Park, NC 27709, USA
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Haseman J, Melnick R, Tomatis L, Huff J. Carcinogenesis bioassays: study duration and biological relevance. Food Chem Toxicol 2001; 39:739-44. [PMID: 11397520 DOI: 10.1016/s0278-6915(01)00010-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Criticisms of the scientific value of rodent carcinogenicity bioassays have focused on the arguments that the studies are too long and that most organ-specific carcinogenic effects observed in experimental animals have little or no relevance to humans. For example, Davies et al. (Davies, T.S., Lynch, B.S., Monro, A.M., Munro, I.C., Nestmann, E.R., 2000. Rodent carcinogenicity tests need be no longer than 18 months: an analysis based on 210 chemicals in the IARC Monographs. Food and Chemical Toxicology 38, 219-235) concluded that the duration of rodent bioassays should be no more than 18 months, based on their analysis of 210 International Agency for Research on Cancer (IARC) rodent carcinogens in which they report that most chemicals showed "tumorigenic effects" at or before 12 months. However, many of these "tumorigenic effects" reflect the occurrence of a single neoplasm, with most tumors occurring much later in the study. Reliance on a single tumor at an early time point as providing definitive evidence of rodent carcinogenicity is a dangerous practice that could produce both false positive and false negative outcomes. An extensive evaluation of the NTP database reveals that many rodent carcinogens produce later-appearing tumors that would not be detected as statistically significant in a 12-18 month study. Such a shortened duration study would be roughly equivalent to evaluating human cancer in subjects 30-50 years of age, which would result in markedly reduced study sensitivity. In fact, many investigators recommend extending the duration of rodent studies to 30 months or to a true lifetime to increase study sensitivity. We also do not agree with the second conclusion of Davies et al. (2000) that the mode of action of rodent carcinogenesis is sufficiently well understood to justify discounting the majority of organ-specific carcinogenic effects found in these studies. The consequences of performing rodent carcinogenicity studies with inadequate sensitivity, and then discounting most of the carcinogenic effects that are observed will be that potential human carcinogens will not be detected, thus forcing near total reliance on human studies for this purpose. This is not prudent public health policy.
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Affiliation(s)
- J Haseman
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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