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Toxicology Nov 2015Risk assessments of arsenic have focused on skin, bladder, and lung cancers and skin lesions as the sensitive cancer and non-cancer health endpoints, respectively;... (Review)
Review
UNLABELLED
Risk assessments of arsenic have focused on skin, bladder, and lung cancers and skin lesions as the sensitive cancer and non-cancer health endpoints, respectively; however, an increasing number of epidemiologic studies that can inform risk assessment have examined neurodevelopmental effects in children. We conducted a systematic review and risk assessment based on the epidemiologic literature on possible neurodevelopmental effects at lower arsenic exposures. Twenty-four cross-sectional, case-control, and cohort studies were identified that report on the association between low-level arsenic exposure (i.e., largely <100 μg/L of arsenic in drinking water) and neurological outcomes in children. Although the overall evidence does not consistently show a causal dose-response relationship at low doses, the most rigorously conducted studies from Bangladesh indicate possible inverse associations with cognitive function, predominantly involving concurrent arsenic exposure as measured by biomarkers (i.e., arsenic in urine or blood) and raw verbal test scores at ages 5-11 years. Issues such as non-comparability of outcome measures across studies; inaccuracies of biomarkers and other measures of inorganic arsenic exposure; potential effect modification by cultural practices; insufficient adjustment for nutritional deficiencies, maternal IQ, and other important confounders; and presence of other neurotoxicants in foreign populations limit generalizability to U.S.
POPULATIONS
Of the few U.S. studies available, the most rigorously conducted study did not find a consistent dose-response relationship between arsenic concentrations in tap water or toenails and decrements in IQ scores. Assuming that the strongest dose-response relationship from the most rigorous evidence from Bangladesh is generalizable to U.S. populations, possible reference doses were estimated in the range of 0.0004-0.001 mg/kg-day. These doses are higher than the U.S. Environmental Protection Agency reference dose for chronic lifetime exposure, thus indicating protectiveness of the existing value for potential neurotoxicity in children. This reference dose is undergoing revision as EPA considers various health endpoints in the reassessment of inorganic arsenic health risks.
Topics: Adolescent; Arsenic; Arsenicals; Child; Child, Preschool; Developmental Disabilities; Female; Humans; Infant; Infant, Newborn; Neurotoxicity Syndromes; Pregnancy; Water Pollutants, Chemical
PubMed: 26388044
DOI: 10.1016/j.tox.2015.09.002 -
International Journal of Environmental... Apr 2020: Arsenic is a toxic metalloid element widely distributed throughout the environment. Arsenic contaminated water has become an ongoing public health issue affecting...
: Arsenic is a toxic metalloid element widely distributed throughout the environment. Arsenic contaminated water has become an ongoing public health issue affecting hundred million people worldwide. The aim of this paper was to summarize the evidence in the association between arsenic metabolites and urinary tract cancer risk. : A systematic review was conducted searching for observational studies that evaluated the association of arsenic metabolites and urinary tract cancer. Risk estimates from individual studies were pooled by using random effects models. : All the metabolites considered in this study resulted to be significantly associated to urothelial cancer, respectively: IA% 3.51 (1.21-5.82) ( = 0.003), MMA with WMD = 2.77 (1.67-3.87) ( < 0.001) and DMA with WMD = -4.56 (-7.91-1.22) ( = 0.008). : Arsenic metabolites are significantly associated to urothelial cancer. Future studies will help to verify the independent association(s) between arsenic metabolites and urothelial cancer.
Topics: Arsenic; Arsenicals; Carcinoma, Transitional Cell; Environmental Exposure; Humans; Observational Studies as Topic; Urologic Neoplasms
PubMed: 32365627
DOI: 10.3390/ijerph17093105 -
Cancer Reports (Hoboken, N.J.) Mar 2024Recent advances in the treatment of acute promyelocytic leukemia (APML) have seen unprecedented improvements in patient outcomes. However, such rapid growth in... (Review)
Review
BACKGROUND
Recent advances in the treatment of acute promyelocytic leukemia (APML) have seen unprecedented improvements in patient outcomes. However, such rapid growth in understanding often leads to uncertainty regarding superiority among candidate treatment regimens, especially when further scrutinized from an epidemiological perspective.
AIMS
The aim of this systematic review with epidemiological analysis was to identify and compare commonly utilized protocols for standard-risk APML with a particular focus on complete remission (CR), overall/disease-free survival (DFS), and reported adverse events.
METHODS AND RESULTS
Medline, Scopus, and CINAHL were interrogated to identify studies utilizing all-trans retinoic acid (ATRA) in addition to arsenic trioxide (ATO) and/or anthracyclines such as idarubicin (IDA) in the treatment of de-novo APML. After collation of studies, an epidemiological analysis was subsequently performed to compare protocols with regards to outcomes of interest using number needed to benefit (NNB) and number needed to harm (NNH) measures. Seventeen articles, describing 12 distinct trials, were included in the analysis. These trials made use of three unique protocols; CR rates were 94%-100% for ATO/ATRA regimens, 95%-96% for ATO/ATRA/anthracycline regimens, and 89%-94% for ATRA/anthracycline regimens. Epidemiological analysis demonstrated NNB for CR was 9.09 (ATO/ATRA vs. ATRA/IDA) and 20.00 (ATO/ATRA vs. ATO/ATRA/IDA), NNH for neutropenia was -3.45 (ATO/ATRA vs. ATRA/IDA), and NNH for infection was -3.13 (ATO/ATRA vs. ATRA/IDA) and -1.89 (ATO/ATRA vs. ATO/ATRA/IDA).
CONCLUSION
The ATO/ATRA regimen is superior to chemotherapy-containing protocols at inducing remission and promoting survival in patients with APML. The regimen is better tolerated than the proposed alternatives with fewer adverse events. Future research opportunities include quantifying APML epidemiology and pursuing oral arsenic as an option for simplification of therapeutic protocols.
Topics: Humans; Leukemia, Promyelocytic, Acute; Anthracyclines; Arsenicals; Oxides; Treatment Outcome; Tretinoin; Antibiotics, Antineoplastic; Pathologic Complete Response
PubMed: 38507294
DOI: 10.1002/cnr2.2035 -
Medicine May 2018Primary hepatic carcinoma (PHC) is the third commonest leading to cancer death around the world, and transarterial chemoembolization (TACE) has been proposed as the... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Primary hepatic carcinoma (PHC) is the third commonest leading to cancer death around the world, and transarterial chemoembolization (TACE) has been proposed as the first-line therapeutic treatment for patients with unresectable PHC. This study aims to determine whether the combination of As2O3 and TACE is superior to alone TACE for achieving more clinical therapeutic efficacy, survival time, life quality and safety in patients with unresectable PHC.
METHODS
A comprehensive literature search was conducted on the clinical controlled trials comparing therapeutic effects of As2O3 & TACE versus alone TACE for unresectable PHC through English databases (including PubMed, Embase, and the Cochrane Library) and Chinese databases (including China Knowledge Resource Integrated Database, Wanfang Database, Weipu Database, and Chinese Biomedical Database). The last search was in 30 August 2017. A recursive search was performed with bibliographies of relevant studies. There were no language restrictions. Primary outcomes, defined a priori, were therapeutic responses (clinical effective rate and clinical benefit rate), survival time, life quality, and adverse events of As2O3 & TACE compared with alone TACE expressed as relative risk (RR) with 95% confidence intervals (CI).
RESULTS
25 clinical controlled trials involving 1886 participants were included. We found that there were significant superiority associated with As2O3 & TACE compared with alone TACE in clinical benefit rate (RR: 1.24, 95% CI: 1.12-1.37), clinical effective rate (RR: 1.35, 95% CI: 1.17-1.55), 2-year survival rate (RR: 1.45, 95% CI: 1.20-1.75), and improving of KPS (RR: 1.31, 95% CI: 1.14-1.50). These associations were also observed in subgroups by intervened methods of As2O3 and pulmonary metastasis. Notably, the pooled relative risk of retention of sodium and water was obviously raised in patients with As2O3 & TACE therapy (RR: 16.616, 95% CI: 8.01 - 34.486).
CONCLUSION
The superiority of adjuvant As2O3 therapy combined with TACE in PHC individuals will outweigh alone TACE therapy, especially in PHC populations with pulmonary metastasis.
Topics: Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Carcinoma, Hepatocellular; Chemoembolization, Therapeutic; Combined Modality Therapy; Humans; Liver Neoplasms; Oxides; Quality of Life; Survival Rate; Treatment Outcome
PubMed: 29718867
DOI: 10.1097/MD.0000000000010613 -
Biological Research May 2017Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetra-sulfide (AsS). Currently, realgar has been... (Review)
Review
Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetra-sulfide (AsS). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.
Topics: Acidithiobacillus thiooxidans; Antineoplastic Agents; Apoptosis; Arsenicals; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Humans; K562 Cells; Sulfides; Toxicological Phenomena
PubMed: 28532516
DOI: 10.1186/s40659-017-0122-y -
Environment International Nov 2020There are unique challenges in estimating dose-response with chemicals that are associated with multiple health outcomes and numerous studies. Some studies are more...
There are unique challenges in estimating dose-response with chemicals that are associated with multiple health outcomes and numerous studies. Some studies are more suitable than others for quantitative dose-response analyses. For such chemicals, an efficient method of screening studies and endpoints to identify suitable studies and potentially important health effects for dose-response modeling is valuable. Using inorganic arsenic as a test case, we developed a tiered approach that involves estimating study-specific margin of exposure (MOE)-like unitless ratios for two hypothetical scenarios. These study-specific unitless ratios are derived by dividing the exposure estimated to result in a 20% increase in relative risk over the background exposure (RRE) by the background exposure, as estimated in two different ways. In our case study illustration, separate study-specific ratios are derived using estimates of United States population background exposure (RRB-US) and the mean study population reference group background exposure (RRB-SP). Systematic review methods were used to identify and evaluate epidemiologic studies, which were categorized based on study design (case-control, cohort, cross-sectional), various study quality criteria specific to dose-response analysis (number of dose groups, exposure ascertainment, exposure uncertainty), and availability of necessary dose-response data. Both case-control and cohort studies were included in the RRB analysis. The RRE estimates were derived by modeling effective counts of cases and controls estimated from study-reported adjusted odds ratios and relative risks. Using a broad (but not necessarily comprehensive) set of epidemiologic studies of multiple health outcomes selected for the purposes of illustrating the RRB approach, this test case analysis would suggest that diseases of the circulatory system, bladder cancer, and lung cancer may be arsenic health outcomes that warrant further analysis. This is suggested by the number of datasets from adequate dose-response studies demonstrating an effect with RRBs close to 1 (i.e., RRE values close to estimated background arsenic exposure levels).
Topics: Arsenic; Arsenicals; Cohort Studies; Cross-Sectional Studies; Environmental Exposure; Epidemiologic Studies; Humans; Risk Assessment; United States
PubMed: 32871380
DOI: 10.1016/j.envint.2020.105986