Peak Exposures in Epidemiologic Studies and Cancer Risks: Considerations for Regulatory Risk Assessment

AbstractWe review approaches for characterizing “peak” exposures in epidemiologic studies and methods for incorporating peak exposure metrics in dose–response assessments that contribute to risk assessment. The focus was on potential etiologic relations between environmental chemical exposures and cancer risks. We searched the epidemiologic literature on environmental chemicals classified as carcinogens in which cancer risks were described in relation to “peak” exposures. These articles were evaluated to identify some of the challenges associated with defining and describing cancer risks in relation to peak exposures. We found tha t definitions of peak exposure varied considerably across studies. Of nine chemical agents included in our review of peak exposure, six had epidemiologic data used by the U.S. Environmental Protection Agency (US EPA) in dose–response assessments to derive inhalation unit risk values. These were be nzene, formaldehyde, styrene, trichloroethylene, acrylonitrile, and ethylene oxide. All derived unit risks relied on cumulative exposure for dose–response estimation and none, to our knowledge, considered peak exposure metrics. This is not surprising, given the historical linear no‐threshold def ault model (generally based on cumulative exposure) used in regulatory risk assessments. With newly proposed US EPA rule language, fuller consideration of alternative exposure and dose–response metrics will be suppo...
Source: Risk Analysis - Category: International Medicine & Public Health Authors: Tags: Original Research Article Source Type: research

Related Links:

Authors: Cao M, Zhou M, Zhang J Abstract Patients with metastatic colorectal cancer (mCRC) beyond second line treatment have a poor prognosis. Regorafenib, TAS-102, fruquintinib, panitumumab and cetuximab are recommended single-agent chemotherapy regimens for patients exhibiting disease progression, this meta-analysis aimed to evaluate the efficacy and safety of these regimens in randomized controlled trials (RCTs). Eight RCTs with 3,832 cancer patients were included. Results showed that there was no significant difference in OS and PFS among the four drugs when comparing all patients or patients who have the KRAS ...
Source: Journal of Chemotherapy - Category: Cancer & Oncology Tags: J Chemother Source Type: research
CONCLUSION: The best of our knowledge it is the third description of brachial plexus schwannoma associated with breast cancer and the first with a synchronous association. The knowledge of this pathology and its potential to alter treatment justify the reporting of the present case. PMID: 32083563 [PubMed - as supplied by publisher]
Source: Breast Disease - Category: Cancer & Oncology Tags: Breast Dis Source Type: research
In this study, dosimeters were used to measure the testicular dose with and without testicular shielding to verify the effect of shielding. Anthropomorphic phantoms representing a human were used to estimate the doses absorbed in testicular and whole-body studies. The anthropomorphic phantom was irradiated according to the treatment protocol for colorectal cancer. Measurements were made using optically-stimulated luminescent dosimeters (OSLDs), composed of carbon-doped aluminum oxide, with characteristics suitable for radiotherapy dosimetry studies. A set of OSLDs was placed on a testicular phantom, attached to the lower e...
Source: Radiation Physics and Chemistry - Category: Physics Source Type: research
Conclusion: Cytokine-induced killer cell immunotherapy combined with first-line chemotherapy could significantly improve the OS and PFS of patients with mCRC, particularly for patients with metastatic colon cancer. PMID: 32076550 [PubMed]
Source: Clinical Colorectal Cancer - Category: Cancer & Oncology Authors: Tags: Clin Transl Immunology Source Type: research
Authors: Herold A Abstract Hemorrhoidal disease is one of the most common illnesses in industrialized nations. Up to 70% of adults suffer from the disease once in their lifetime. This underlines the necessity and importance of knowing about the differential diagnosis of hemorrhoids. One can differentiate between differential diagnoses of symptoms (bleeding, pain, itching, tumor) and differential diagnoses of the phenotype findings (anal prolapse, mucosal prolapse and rectal prolapse, skin tags, hypertrophied anal papillae, condylomata acuminata, anal fissure, perianal venous thrombosis, anal cancer). PMID: 3207...
Source: Der Hautarzt: Zeitschrift fur Dermatologie, Venerologie, und verwandte Gebiete - Category: Dermatology Tags: Hautarzt Source Type: research
Publication date: Available online 22 February 2020Source: Life SciencesAuthor(s): Maryam Ezzati, Bahman Yousefi, Kobra Velaei, Amin SafaAbstractBreast cancer is one of the well-known malignant tumors among women. In spite of attempts to classifying breast cancer according to its histological and molecular properties, it is almost considered as a dilemma in treatment. Nowadays, public and medical attentions have primary focused on foods with anti-cancer properties to alleviate the cancer problems. Flavonoid components such as Quercetin (Qu) as dietary substances with high attention of ordinary people might provide potentia...
Source: Life Sciences - Category: Biology Source Type: research
Publication date: Available online 22 February 2020Source: Life SciencesAuthor(s): Ning Zhou, Xiao-Bing Zhang, Cheng Chen, Xin-Yu Chen, Bo Kang, Jian-Qin He, Guo-Zhong Gong, Ying-Jie Wang, Yan-Wen ZhouAbstractAimsTo compare how OCT4A proteins interact with and regulate multiple OCT4A-octamer motifs (OMs) in different regions of the FOS gene expressed in somatic cancer cells versus pluripotent stem cells.Materials and methodsTwo FOS reporter gene systems harboring predicted OMs or their mutational counterparts were introduced into HeLa and NCCIT cells with varying OCT4A protein levels. The transcription of dsGFP reflecting ...
Source: Life Sciences - Category: Biology Source Type: research
In this study, fluorescence emission spectroscopy and mass spectrometry (MALDI-TOF) were employed to define the putative interaction sites and their accessibility for the biologically important metals of Irving William Series.Key findingsSeveral hotspot residues in the ZAG scaffold involved in these interactions were mapped and their binding affinity score for each metal has been determined. Their binding abilities of these sites and aggregation propensities of ZAG were monitored by fluorescence emission spectroscopy.SignificanceThe prediction of such binding affinity with metals on the active sites and its impact on the c...
Source: Life Sciences - Category: Biology Source Type: research
Publication date: Available online 21 February 2020Source: PolymerAuthor(s): Inès Hamouda, Cédric Labay, Maria Pau Ginebra, Erwan Nicol, Cristina CanalAbstractAtmospheric pressure plasma jets (APPJ) have great potential in wound healing, bacterial disinfection and in cancer therapy. Recent studies pointed out that hydrogels can be used as screens during APPJ treatment, or even be used as reservoirs for reactive oxygen and nitrogen species generated by APPJ in liquids. Thus, novel applications are emerging for hydrogels which deserve fundamental exploration of the possible modifications undergone by the polyme...
Source: Polymer - Category: Chemistry Source Type: research
Publication date: Available online 21 February 2020Source: Chinese Chemical LettersAuthor(s): Lei Zhou, Chang Du, Rong Zhang, Changming DongAbstractWe developed one-pot aqueous copolymerization of two dopamine prodrugs to prepare dual drugs-conjugated polydopamine nanoparticles (PDOXCBs), which integrated near infrared (NIR)-mediated photothermal effect with cocktail chemotherapy into one copolymer nanoparticle. Upon a mild NIR irradiation (808 nm, 1 W/cm2, 10 min), PDOXCBs gradually heated aqueous solution over 12.8―13.9 °C, which accordingly enhanced in vitro dual doxorubicin (DOX) and c...
Source: Chinese Chemical Letters - Category: Chemistry Source Type: research
More News: Cancer | Cancer & Oncology | Chemistry | Environmental Health | Epidemiology | History of Medicine | International Medicine & Public Health | Study