1 452 129 APPLICATION OF THE KEY CHARACTERISTICS OF CARCINOGENS TO PER AND POLYFLUOROALKYL SUBSTANCES. PER- AND POLYFLUOROALKYL SUBSTANCES (PFAS) CONSTITUTE A LARGE CLASS OF ENVIRONMENTALLY PERSISTENT CHEMICALS USED IN INDUSTRIAL AND CONSUMER PRODUCTS. HUMAN EXPOSURE TO PFAS IS EXTENSIVE, AND PFAS CONTAMINATION HAS BEEN REPORTED IN DRINKING WATER AND FOOD SUPPLIES AS WELL AS IN THE SERUM OF NEARLY ALL PEOPLE. THE MOST WELL-STUDIED MEMBER OF THE PFAS CLASS, PERFLUOROOCTANOIC ACID (PFOA), INDUCES TUMORS IN ANIMAL BIOASSAYS AND HAS BEEN ASSOCIATED WITH ELEVATED RISK OF CANCER IN HUMAN POPULATIONS. GENX, ONE OF THE PFOA REPLACEMENT CHEMICALS, INDUCES TUMORS IN ANIMAL BIOASSAYS AS WELL. USING THE KEY CHARACTERISTICS OF CARCINOGENS FRAMEWORK FOR CANCER HAZARD IDENTIFICATION, WE CONSIDERED THE EXISTING EPIDEMIOLOGICAL, TOXICOLOGICAL AND MECHANISTIC DATA FOR 26 DIFFERENT PFAS. WE FOUND STRONG EVIDENCE THAT MULTIPLE PFAS INDUCE OXIDATIVE STRESS, ARE IMMUNOSUPPRESSIVE, AND MODULATE RECEPTOR-MEDIATED EFFECTS. WE ALSO FOUND SUGGESTIVE EVIDENCE INDICATING THAT SOME PFAS CAN INDUCE EPIGENETIC ALTERATIONS AND INFLUENCE CELL PROLIFERATION. EXPERIMENTAL DATA INDICATE THAT PFAS ARE NOT GENOTOXIC AND GENERALLY DO NOT UNDERGO METABOLIC ACTIVATION. DATA ARE CURRENTLY INSUFFICIENT TO ASSESS WHETHER ANY PFAS PROMOTE CHRONIC INFLAMMATION, CELLULAR IMMORTALIZATION OR ALTER DNA REPAIR. WHILE MORE RESEARCH IS NEEDED TO ADDRESS DATA GAPS, EVIDENCE EXISTS THAT SEVERAL PFAS EXHIBIT ONE OR MORE OF THE KEY CHARACTERISTICS OF CARCINOGENS. 2020 2 6484 28 TOXICOLOGIC PROFILE OF ACRYLONITRILE. ACRYLONITRILE IS A MONOMER USED EXTENSIVELY AS A RAW MATERIAL IN THE MANUFACTURING OF ACRYLIC FIBERS, PLASTICS, SYNTHETIC RUBBERS, AND ACRYLAMIDE. IT HAS BEEN CLASSIFIED AS A PROBABLE HUMAN CARCINOGEN ACCORDING TO THE RESULTS OF NUMEROUS CHRONIC RAT BIOASSAYS. THE PRESENT REPORT SUMMARIZES THE TOXICITY DATA ON ACRYLONITRILE AND REVIEWS AVAILABLE DATA CONCERNING THE MECHANISM (GENETIC VERSUS EPIGENETIC) BY WHICH ACRYLONITRILE IS CARCINOGENIC IN RATS. FROM THE EVALUATION OF THE RELEVANT TOXICITY DATA, IT CAN BE CONCLUDED THAT ACRYLONITRILE IS INDEED CARCINOGENIC TO RATS AFTER EITHER ORAL OR INHALATIONAL EXPOSURE. HOWEVER, INFORMATION ON OTHER MAMMALIAN SPECIES IS LACKING, AND, MOREOVER, THE EXACT MECHANISM OF THE CARCINOGENIC PROCESS IS UNCLEAR. THEREFORE, IT IS RECOMMENDED TO CONDUCT AN ADDITIONAL LONG-TERM INHALATION CARCINOGENICITY STUDY WITH ACRYLONITRILE IN MICE, AS WELL AS STUDIES INTO THE MECHANISM BY WHICH ACRYLONITRILE INDUCES (BRAIN) TUMORS IN RATS (GENETIC VERSUS EPIGENETIC). 1998 3 3899 26 LATE NEUROLOGICAL CONSEQUENCES OF ZIKA VIRUS INFECTION: RISK FACTORS AND PHARMACEUTICAL APPROACHES. ZIKA VIRUS (ZIKV) INFECTION WAS HISTORICALLY CONSIDERED A DISEASE WITH MILD SYMPTOMS AND NO MAJOR CONSEQUENCES TO HUMAN HEALTH. HOWEVER, SEVERAL LONG-TERM, LATE ONSET, AND CHRONIC NEUROLOGICAL COMPLICATIONS, BOTH IN CONGENITALLY-EXPOSED BABIES AND IN ADULT PATIENTS, HAVE BEEN REPORTED AFTER ZIKV INFECTION, ESPECIALLY AFTER THE 2015 EPIDEMICS IN THE AMERICAN CONTINENT. THE DEVELOPMENT OR SEVERITY OF THESE CONDITIONS CANNOT BE FULLY PREDICTED, BUT IT IS POSSIBLE THAT GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS MAY CONTRIBUTE TO DETERMINE ZIKV INFECTION OUTCOMES. THIS REINFORCES THE IMPORTANCE THAT INDIVIDUALS EXPOSED TO ZIKV ARE SUBMITTED TO LONG-TERM CLINICAL SURVEILLANCE AND HIGHLIGHTS THE URGENT NEED FOR THE DEVELOPMENT OF THERAPEUTIC APPROACHES TO REDUCE OR ELIMINATE THE NEUROLOGICAL BURDEN OF INFECTION. HERE, WE REVIEW THE EPIDEMIOLOGY OF ZIKV-ASSOCIATED NEUROLOGICAL COMPLICATIONS AND THE ROLE OF FACTORS THAT MAY INFLUENCE DISEASE OUTCOME. MOREOVER, WE DISCUSS EXPERIMENTAL AND CLINICAL EVIDENCE OF DRUGS THAT HAVE SHOWN PROMISING RESULTS IN VITRO OR IN VITRO AGAINST VIRAL REPLICATION AND AND/OR ZIKV-INDUCED NEUROTOXICITY. 2019 4 6464 26 TISSUE MISREPAIR HYPOTHESIS FOR RADIATION CARCINOGENESIS. DOSE-RESPONSE CURVES FOR CHRONIC LEUKEMIA IN A-BOMB SURVIVORS AND LIVER TUMORS IN PATIENTS GIVEN THOROTRAST (COLLOIDAL THORIUM DIOXIDE) SHOW LARGE THRESHOLD EFFECTS. THE EXISTENCE OF THESE THRESHOLD EFFECTS CAN BE EXPLAINED BY THE FOLLOWING HYPOTHESIS. A HIGH DOSE OF RADIATION CAUSES A PERSISTENT WOUND IN A CELL-RENEWABLE TISSUE. DISORDER OF THE INJURED CELL SOCIETY PARTLY FREES THE COMPONENT CELLS FROM TERRITORIAL RESTRAINTS ON THEIR PROLIFERATION, ENABLING THEM TO CONTINUE DEVELOPMENT OF THEIR CELLULAR FUNCTIONS TOWARD ADVANCED AUTONOMY. THIS PROGRESSION MIGHT BE ACHIEVED BY CONTINUED EPIGENETIC AND GENETIC CHANGES AS A RESULT OF OCCASIONAL ERRORS IN THE OTHERWISE CONCERTED HEALING ACTION OF VARIOUS ENDOGENOUS FACTORS RECRUITED FOR TISSUE REPAIR. CARCINOGENESIS IS NOT SIMPLY A SINGLE-CELL PROBLEM BUT A CELL-SOCIETY PROBLEM. THEREFORE, IT IS NOT WARRANTED TO ESTIMATE RISK AT LOW DOSES BY LINEAR EXTRAPOLATION FROM CANCER DATA AT HIGH DOSES WITHOUT KNOWLEDGE OF THE MECHANISM OF RADIATION CARCINOGENESIS. 1991 5 4019 30 LOW-DOSE OR LOW-DOSE-RATE IONIZING RADIATION-INDUCED BIOEFFECTS IN ANIMAL MODELS. ANIMAL EXPERIMENTAL STUDIES INDICATE THAT ACUTE OR CHRONIC LOW-DOSE IONIZING RADIATION (LDIR) (