Based on epidemiological studies, an International Agency for Research on Cancer Working Group determined that strong inorganic acid mists containing sulfuric acid are carcinogenic to human even though, sulfuric acid, per se, is not. Accumulative studies indicate that there is a link between chronic occupational exposure to sulfuric acid mists and an increased risk of laryngeal cancer. Unintended, acute exposure to sulfuric acid mists can cause corrosive damage to target tissues depending on the route of exposure. This review compares the toxicity and carcinogenicity of sulfuric acid mists compared to other strong inorganic acid mists. It also examines the routes and duration of exposure (short-term, prolonged, and long-term). In vivo evidence does not support or refute the carcinogenicity of sulfuric inorganic mists even though its co-carcinogenic or promoting potential has been considered. On the basis of existing evidence on sulfuric acid mist toxicity, we suggested a putative adverse outcome pathway (AOP) relevant to carcinogenicity caused by mists containing sulfuric acid. A possible key factor involved in sulfuric acid mist carcinogenesis is the genotoxic effects of low pH since it can increase instability in chromosomes and DNA. A putative AOP for sulfuric acid mist carcinogenicity would help generate better risk assessments and more accurate predictions regarding the risk of developing cancer due to prolonged exposure. Establishing an AOP would also be useful for future studies examining the carcinogenicity of other strong inorganic mists.
Carcinogenesis ; Chemical Hazard Release ; DNA ; Epidemiologic Studies ; Humans ; Hydrogen-Ion Concentration ; International Agencies ; Laryngeal Neoplasms ; Occupational Exposure ; Risk Assessment ; Sulfur ; Sulfuric Acids

As industry develops in modern society, many chemicals are being used. The safety of chemicals is an important issue because humans are constantly exposed to chemicals throughout their daily life. Through a risk assessment, the hazardous human effects of chemicals can be identified. Recently, the adverse outcome pathway (AOP) framework has been used to predict the adverse effects of chemicals. As a conceptual framework for organizing existing biological knowledge, the AOP consists of a molecular initiating event, key events, and an adverse outcome. These independent elements represent biological responses and are connected by key event relationships. This AOP framework provides intuitive hazard identification that can be helpful for carcinogenic risk assessment of chemicals. In this review, we introduce the application of the AOP framework to risk assessment for predicting carcinogenicity of chemicals and illustrate the utility of this approach for cancer prevention.
Carcinogenesis ; Chemical Safety ; Humans ; Risk Assessment

BACKGROUND/AIMS: Radiofrequency ablation (RFA) and transarterial chemoembolization (TACE) have been applied for treating hepatocellular carcinoma (HCC), but procedure-related complications can be a serious problem. This study was conducted to evaluate the clinical features of HCC patients who developed liver abscess after RFA and TACE, as compared to those patients without malignancy. METHODS: In our center, from December 1999 to March 2004, 31 cases of liver abscess developed after local treatment of HCC (13/751 after RFA and 18/8417 after TAE), which correspond to 5.1% of the total cases (602) of liver abscess. We evaluated the patients' clinical features, the abscess characteristics, the bacteriology, treatment modality, hospital days and mortality, as compared to those characteristics of 263 abscess patients without malignancy. RESULTS: The time required to diagnose liver abscess was longer in the TACE group (24.8+/-16.5 days) compared to that of the other two groups (12.2+/-9.0 days in the RFA group, 9.6+/-7.5 days in the controls, P=0.001). Gas-forming liver abscess is most frequently found in the RFA groups (76.9%). There were more hospitalized days for the TACE groups than for the RFA group and the controls (34.7+/-19.8 vs. 15.2+/-9.2 vs. 18.6+/-10.9 days, respectively, P<0.001). Two patients (11%) in the TACE group died of sepsis and liver failure. CONCLUSIONS: For the patients with prolonged fever after RFA and especially after TACE for HCC, a diagnosis of liver abscess should be suspected earlier to reduce the morbidity and mortality due to liver abscess per se and also the sepsis-related decompensation of the liver.
Middle Aged ; Male ; Liver Neoplasms/surgery/*therapy ; Liver Abscess/diagnosis/*etiology/microbiology ; Humans ; Female ; Chemoembolization, Therapeutic/*adverse effects ; Catheter Ablation/*adverse effects ; Carcinoma, Hepatocellular/surgery/*therapy ; Aged ; Adult

Brown adipose tissue (BAT) plays a fundamental role in maintaining body temperature by producing heat. BAT that had been know to exist only in mammals and the human neonate has received great attention for the treatment of obesity and diabetes due to its important function in energy metabolism, ever since it is recently reported that human adults have functional BAT. In addition, beige adipocytes, brown adipocytes in white adipose tissue (WAT), have also been shown to take part in whole body metabolism. Multiple lines of evidence demonstrated that transplantation or activation of BAT or/and beige adipocytes reversed obesity and improved insulin sensitivity. Furthermore, many genes involved in BATactivation and/or the recruitment of beige cells have been found, thereby providing new promising strategies for future clinical application of BAT activation to treat obesity and metabolic diseases. This review focuses on recent advances of BAT function in the metabolic aspect and the relationship between BAT and cancer cachexia, a pathological process accompanied with decreased body weight and increased energy expenditure in cancer patients. The underlying possible mechanisms to reduce BAT mass and its activity in the elderly are also discussed.
Adipose Tissue, Brown ; metabolism ; Aging ; metabolism ; Animals ; Cachexia ; metabolism ; pathology ; Disease Models, Animal ; Energy Metabolism ; Humans ; Metabolic Syndrome ; metabolism ; Neoplasms ; metabolism ; pathology ; Obesity ; metabolism ; Thermogenesis