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Environment International Oct 2020The environmental health community needs transparent, methodologically rigorous, and rapid approaches for updating human health risk assessments. These assessments often...
BACKGROUND
The environmental health community needs transparent, methodologically rigorous, and rapid approaches for updating human health risk assessments. These assessments often contain reference values for cancer and/or noncancer effects. Increasingly, the use of systematic review methods are preferred when developing these assessments. Systematic evidence maps are a type of analysis that has the potential to be very helpful in the update process, especially when combined with machine-learning software advances designed to expedite the process of conducting a review.
OBJECTIVES
To evaluate the applicability of evidence mapping to determine whether new evidence is likely to result in a change to an existing health reference value, using inhalation exposure to the air pollutant acrolein as a case example.
METHODS
New literature published since the 2008 California Environmental Protection Agency's Office of Environmental Health Hazard Assessment (OEHHA) Reference Exposure Level (REL) for acrolein was assessed. Systematic review methods were used to search the literature and screening included the use of machine-learning software. The Populations, Exposures, Comparators and Outcomes (PECO) criteria were kept broad to identify studies that characterized acute and chronic exposure and could be informative for hazard characterization. Studies that met the PECO criteria after full-text review were briefly summarized before their suitability for chronic point of departure (POD) derivation and calculation of a reference value was considered. Studies considered potentially suitable underwent a targeted evaluation to determine their suitability for use in dose-response analysis.
RESULTS
Over 15,000 studies were identified from scientific databases. Both machine-learning and manual screening processes were used to identify 60 studies considered PECO-relevant after full-text review. Most of these PECO-relevant studies were short-term exposure animal studies (acute or less than 1 month of exposure) and considered less suitable for deriving a chronic reference value when compared to the subchronic study in rats used in the 2008 OEHHA assessment. Thirteen epidemiological studies were identified but had limitations in the exposure assessment that made them less suitable for dose-response compared to the subchronic rat study. Among the 13 studies, there were four controlled trial studies that have the potential to be informative for future acute reference value derivation. Thus, the 2008 subchronic rat study used by OEHHA appears to still be the most appropriate study for chronic reference value derivation. In addition, advances in dosimetric modeling for gases, including new evidence pertinent to acrolein, could be considered when updating existing acrolein toxicity values.
CONCLUSIONS
Evidence mapping is a very useful tool to assess the need for updating an assessment based on understanding the potential impact of new studies on revising an existing health reference value. In this case example, the focus was to identify studies suitable for chronic exposure dose-response analysis, while also identifying studies that may be important to consider for acute exposure scenarios, hazard identification, or for future research. This allows the evidence map to be a useful resource for a range of decision-making contexts. Specialized systematic review software increased the efficiency of the process in terms of human resources and time to conduct the analysis.
Topics: Acrolein; Air Pollutants; Animals; Environmental Health; Humans; Rats; Reference Values; Risk Assessment
PubMed: 32702594
DOI: 10.1016/j.envint.2020.105956 -
Cancer Biology & Medicine Feb 2020Upper gastrointestinal (UGI) cancers, predominantly gastric cancer (GC) and esophageal cancer (EC), are malignant tumor types with high morbidity and mortality rates....
Upper gastrointestinal (UGI) cancers, predominantly gastric cancer (GC) and esophageal cancer (EC), are malignant tumor types with high morbidity and mortality rates. Accumulating studies have focused on metabolomic profiling of UGI cancers in recent years. In this systematic review, we have provided a collective summary of previous findings on metabolites and metabolomic profiling associated with GC and EC. A systematic search of three databases (Embase, PubMed, and Web of Science) for molecular epidemiologic studies on the metabolomic profiles of GC and EC was conducted. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the included articles. A total of 52 original studies were included for review. A number of metabolites were differentially distributed between GC and EC cases and non-cases, including those involved in glycolysis, anaerobic respiration, tricarboxylic acid cycle, and protein and lipid metabolism. Lactic acid, glucose, citrate, and fumaric acid were among the most frequently reported metabolites of cellular respiration while glutamine, glutamate, and valine were among the most commonly reported amino acids. The lipid metabolites identified previously included saturated and unsaturated free fatty acids, aldehydes, and ketones. However, the key findings across studies to date have been inconsistent, potentially due to limited sample sizes and the majority being hospital-based case-control analyses lacking an independent replication group. Studies on metabolomics have thus far provided insights into etiological factors and biomarkers for UGI cancers, supporting the potential of applying metabolomic profiling in cancer prevention and management efforts.
Topics: Amino Acids; Biomarkers, Tumor; Esophageal Neoplasms; Humans; Lipid Metabolism; Metabolomics; Stomach Neoplasms; Warburg Effect, Oncologic
PubMed: 32296585
DOI: 10.20892/j.issn.2095-3941.2019.0348 -
Nutrients Apr 2020Exposure of polyunsaturated fatty acid (PUFA)-rich culinary oils (COs) to high temperature frying practices generates high concentrations of cytotoxic and genotoxic...
Exposure of polyunsaturated fatty acid (PUFA)-rich culinary oils (COs) to high temperature frying practices generates high concentrations of cytotoxic and genotoxic lipid oxidation products (LOPs) via oxygen-fueled, recycling peroxidative bursts. These toxins, including aldehydes and epoxy-fatty acids, readily penetrate into fried foods and hence are available for human consumption; therefore, they may pose substantial health hazards. Although previous reports have claimed health benefits offered by the use of PUFA-laden COs for frying purposes, these may be erroneous in view of their failure to consider the negating adverse public health threats presented by food-transferable LOPs therein. When absorbed from the gastrointestinal (GI) system into the systemic circulation, such LOPs may significantly contribute to enhanced risks of chronic non-communicable diseases (NCDs), e.g. cancer, along with cardiovascular and neurological diseases. Herein, we provide a comprehensive rationale relating to the public health threats posed by the dietary ingestion of LOPs in fried foods. We begin with an introduction to sequential lipid peroxidation processes, describing the noxious effects of LOP toxins generated therefrom. We continue to discuss GI system interactions, the metabolism and biotransformation of primary lipid hydroperoxide LOPs and their secondary products, and the toxicological properties of these agents, prior to providing a narrative on chemically-reactive, secondary aldehydic LOPs available for human ingestion. In view of a range of previous studies focused on their deleterious health effects in animal and cellular model systems, some emphasis is placed on the physiological fate of the more prevalent and toxic α,β-unsaturated aldehydes. We conclude with a description of targeted nutritional and interventional strategies, whilst highlighting the urgent and unmet clinical need for nutritional and epidemiological trials probing relationships between the incidence of NCDs, and the frequency and estimated quantities of dietary LOP intake.
Topics: Cooking; Dietary Fats, Unsaturated; Fatty Acids, Unsaturated; Food Quality; Gastrointestinal Tract; Hot Temperature; Humans; Intestinal Absorption; Lipid Peroxidation; Mutagens; Noncommunicable Diseases; Nutritional Physiological Phenomena; Public Health; Risk
PubMed: 32244669
DOI: 10.3390/nu12040974 -
BMC Cancer Dec 2019Formaldehyde, a widely used chemical, is considered a human carcinogen. We report the results of a meta-analyses of studies on the relationship between occupational... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Formaldehyde, a widely used chemical, is considered a human carcinogen. We report the results of a meta-analyses of studies on the relationship between occupational exposure to formaldehyde and risk of non-Hodgkin lymphoma (NHL).
METHODS
We performed a systematic review and meta-analysis according to international guidelines and we identified 12 reports of occupational populations exposed to formaldehyde. We evaluated inter-study heterogeneity and we applied a random effects model. We conducted a cumulative meta-analysis and a meta-analysis according to estimated average exposure of each study population.
RESULTS
The meta-analysis resulted in a summary relative risk (RR) for NHL of 0.93 (95% confidence interval 0.83-1.04). The cumulative meta-analysis suggests that higher RRs were detected in studies published before 1986, while studies available after 1986 did not show an association. No differences were found between different levels of occupational exposure. Conclusions Notwithstanding some limitations, the results of this meta-analysis do not support the hypothesis of an association between occupational exposure to formaldehyde and risk of NHL.
Topics: Disinfectants; Formaldehyde; Humans; Lymphoma, Non-Hodgkin; Occupational Diseases; Occupational Exposure; Risk Assessment; Risk Factors
PubMed: 31870335
DOI: 10.1186/s12885-019-6445-z -
Frontiers in Neurology 2019A number of studies have reported that aldehyde dehydrogenase-2 () polymorphisms maybe associated with the risk of Alzheimer's disease (AD) and Parkinson's disease...
A number of studies have reported that aldehyde dehydrogenase-2 () polymorphisms maybe associated with the risk of Alzheimer's disease (AD) and Parkinson's disease (PD). However, the results of such studies are inconsistent. We therefore conducted a meta-analysis to clarify the association between polymorphisms and the risk of AD and PD. Five online databases were searched and the relevant studies were reviewed from inception through May 10, 2018. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated in each genetic model of the general population and various subgroups. Furthermore, we simultaneously performed heterogeneity, cumulative, sensitivity, and publication bias analyses. Overall, nine case-control studies involving 5,315 subjects were included in this meta-analysis. Potential associations were found between the rs671 G>A polymorphism and the risk of AD (A vs. G: OR = 1.46, 95%CI = 1.01-2.11, = 0.05, = 84.2%; AA vs. GG: OR = 2.22, 95%CI = 1.03-4.77, = 0.04, = 79.2%; AA vs. GG+GA: OR = 1.94, 95%CI = 1.03-3.64, =0.04, = 71.1%). In addition, some similar results were observed in other subgroups. Moreover, no significant association between polymorphisms and PD risk. In conclusion, our meta-analysis indicated that the rs671 G>A polymorphism plays an important role in AD development.
PubMed: 30984100
DOI: 10.3389/fneur.2019.00290 -
Clinical Pharmacokinetics Oct 2019Enzyme-mediated biotransformation of pharmacological agents is a crucial step in xenobiotic detoxification and drug disposition. Herein, we investigated the metabolism...
Physicochemical Properties, Biotransformation, and Transport Pathways of Established and Newly Approved Medications: A Systematic Review of the Top 200 Most Prescribed Drugs vs. the FDA-Approved Drugs Between 2005 and 2016.
BACKGROUND
Enzyme-mediated biotransformation of pharmacological agents is a crucial step in xenobiotic detoxification and drug disposition. Herein, we investigated the metabolism and physicochemical properties of the top 200 most prescribed drugs (established) as well as drugs approved by the US Food and Drug Administration (FDA) between 2005 and 2016 (newly approved).
OBJECTIVE
Our objective was to capture the changing trends in the routes of administration, physicochemical properties, and prodrug medications, as well as the contributions of drug-metabolizing enzymes and transporters to drug clearance.
METHODS
The University of Washington Drug Interaction Database (DIDB) as well as other online resources (e.g., CenterWatch.com, Drugs.com, DrugBank.ca, and PubChem.ncbi.nlm.nih.gov) was used to collect and stratify the dataset required for exploring the above-mentioned trends.
RESULTS
Analyses revealed that ~ 90% of all drugs in the established and newly approved drug lists were administered systemically (oral or intravenous). Meanwhile, the portion of biologics (molecular weight > 1 kDa) was 15 times greater in the newly approved list than established drugs. Additionally, there was a 4.5-fold increase in the number of compounds with a high calculated partition coefficient (cLogP > 3) and a high total polar surface area (> 75 Å) in the newly approved drug vs. the established category. Further, prodrugs in established or newly approved lists were found to be converted to active compounds via hydrolysis, demethylases, and kinases. The contribution of cytochrome P450 (CYP) 3A4, as the major biotransformation pathway, has increased from 40% in the established drug list to 64% in the newly approved drug list. Moreover, the role of CYP1A2, CYP2C19, and CYP2D6 were decreased as major metabolizing enzymes among the newly approved medications. Among non-CYP major metabolizers, the contribution of alcohol dehydrogenases/aldehyde dehydrogenases (ADH/ALDH) and sulfotransferases decreased in the newly approved drugs compared with the established list. Furthermore, the highest contribution among uptake and efflux transporters was found for Organic Anion Transporting Polypeptide 1B1 (OATP1B1) and P-glycoprotein (P-gp), respectively.
CONCLUSIONS
The higher portion of biologics in the newly approved drugs compared with the established list confirmed the growing demands for protein- and antibody-based therapies. Moreover, the larger number of hydrophilic drugs found in the newly approved list suggests that the probability of toxicity is likely to decrease. With regard to CYP-mediated major metabolism, CYP3A5 showed an increased involvement owing to the identification of unique probe substrates to differentiate CYP3As. Furthermore, the contribution of OATP1B1 and P-gp did not show a significant shift in the newly approved drugs as compared to the established list because of their broad substrate specificity.
Topics: Animals; Biological Transport; Biotransformation; Drug Approval; Humans; Prescription Drugs; United States; United States Food and Drug Administration
PubMed: 30972694
DOI: 10.1007/s40262-019-00750-8 -
Protein Science : a Publication of the... Jan 2019An overview is provided of the molybdenum- and tungsten-containing enzymes that catalyze the interconversion of formate and CO , focusing on common structural and...
An overview is provided of the molybdenum- and tungsten-containing enzymes that catalyze the interconversion of formate and CO , focusing on common structural and mechanistic themes, as well as a consideration of the manner in which the mature Mo- or W-containing cofactor is inserted into apoprotein.
Topics: Aldehyde Oxidoreductases; Catalysis; Coenzymes; Formate Dehydrogenases; Molybdenum; Structure-Activity Relationship; Tungsten
PubMed: 30120799
DOI: 10.1002/pro.3498 -
The Cochrane Database of Systematic... May 2018In children, dental caries (tooth decay) is among the most prevalent chronic diseases worldwide. Pulp interventions are indicated for extensive tooth decay. Depending on... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
In children, dental caries (tooth decay) is among the most prevalent chronic diseases worldwide. Pulp interventions are indicated for extensive tooth decay. Depending on the severity of the disease, three pulp treatment techniques are available: direct pulp capping, pulpotomy and pulpectomy. After treatment, the cavity is filled with a medicament. Materials commonly used include mineral trioxide aggregate (MTA), calcium hydroxide, formocresol or ferric sulphate.This is an update of a Cochrane Review published in 2014 when insufficient evidence was found to clearly identify one superior pulpotomy medicament and technique.
OBJECTIVES
To assess the effects of different pulp treatment techniques and associated medicaments for the treatment of extensive decay in primary teeth.
SEARCH METHODS
Cochrane Oral Health's Information Specialist searched the Cochrane Oral Health Group's Trials Register (to 10 August 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2017, Issue 7), MEDLINE Ovid (1946 to 10 August 2017), Embase Ovid (1980 to 10 August 2017) and the Web of Science (1945 to 10 August 2017). OpenGrey was searched for grey literature. The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) comparing interventions that combined a pulp treatment technique with a medicament or device in children with extensive decay in the dental pulp of their primary teeth.
DATA COLLECTION AND ANALYSIS
Two review authors independently extracted data and assessed 'Risk of bias'. We contacted authors of RCTs for additional information when necessary. The primary outcomes were clinical failure and radiological failure, as defined in trials, at six, 12 and 24 months. We performed data synthesis with pair-wise meta-analyses using fixed-effect models. We assessed statistical heterogeneity by using I² coefficients.
MAIN RESULTS
We included 40 new trials bringing the total to 87 included trials (7140 randomised teeth) for this update. All were small, single-centre trials (median number of randomised teeth = 68). All trials were assessed at unclear or high risk of bias.The 87 trials examined 125 different comparisons: 75 comparisons of different medicaments or techniques for pulpotomy; 25 comparisons of different medicaments for pulpectomy; four comparisons of pulpotomy and pulpectomy; and 21 comparisons of different medicaments for direct pulp capping.The proportion of clinical failures and radiological failures was low in all trials. In many trials, there were either no clinical failures or no radiographic failures in either study arm.For pulpotomy, we assessed three comparisons as providing moderate-quality evidence. Compared with formocresol, MTA reduced both clinical and radiological failures, with a statistically significant difference at 12 months for clinical failure and at six, 12 and 24 months for radiological failure (12 trials, 740 participants). Compared with calcium hydroxide, MTA reduced both clinical and radiological failures, with statistically significant differences for clinical failure at 12 and 24 months. MTA also appeared to reduce radiological failure at six, 12 and 24 months (four trials, 150 participants) (low-quality evidence). When comparing calcium hydroxide with formocresol, there was a statistically significant difference in favour of formocresol for clinical failure at six and 12 months and radiological failure at six, 12 and 24 months (six trials (one with no failures), 332 participants).Regarding pulpectomy, we found moderate-quality evidence for two comparisons. The comparison between Metapex and zinc oxide and eugenol (ZOE) paste was inconclusive, with no clear evidence of a difference between the interventions for failure at 6 or 12 months (two trials, 62 participants). Similarly inconclusive, there was no clear evidence of a difference in failure between Endoflas and ZOE (outcomes measured at 6 months; two trials, 80 participants). There was low-quality evidence of a difference in failure at 12 months that suggested ZOE paste may be better than Vitapex (calcium hydroxide/iodoform) paste (two trials, 161 participants).Regarding direct pulp capping, the small number of studies undertaking the same comparison limits any interpretation. We assessed the quality of the evidence as low or very low for all comparisons. One trial appeared to favour formocresol over calcium hydroxide; however, there are safety concerns about formocresol.
AUTHORS' CONCLUSIONS
Pulp treatment for extensive decay in primary teeth is generally successful. Many included trials had no clinical or radiological failures in either trial arm, and the overall proportion of failures was low. Any future trials in this area would require a very large sample size and follow up of a minimum of one year.The evidence suggests MTA may be the most efficacious medicament to heal the root pulp after pulpotomy of a deciduous tooth. As MTA is relatively expensive, future research could be undertaken to confirm if Biodentine, enamel matrix derivative, laser treatment or Ankaferd Blood Stopper are acceptable second choices, and whether, where none of these treatments can be used, application of sodium hypochlorite is the safest option. Formocresol, though effective, has known concerns about toxicity.Regarding pulpectomy, there is no conclusive evidence that one medicament or technique is superior to another, and so the choice of medicament remains at the clinician's discretion. Research could be undertaken to confirm if ZOE paste is more effective than Vitapex and to evaluate other alternatives.Regarding direct pulp capping, the small number of studies and low quality of the evidence limited interpretation. Formocresol may be more successful than calcium hydroxide; however, given its toxicity, any future research should focus on alternatives.
Topics: Aluminum Compounds; Calcium Compounds; Calcium Hydroxide; Child; Child, Preschool; Controlled Clinical Trials as Topic; Dental Caries; Dental Cements; Dental Materials; Drug Combinations; Electric Stimulation Therapy; Ferric Compounds; Formocresols; Humans; Molar; Oxides; Pulpectomy; Pulpotomy; Randomized Controlled Trials as Topic; Silicates; Tooth, Deciduous; Treatment Failure; Zinc Oxide-Eugenol Cement
PubMed: 29852056
DOI: 10.1002/14651858.CD003220.pub3 -
Frontiers in Bioscience (Landmark... Jan 2018Elevated levels of low density lipoproteins (LDLs) cause atherosclerotic disease, and proteomic analyses have found that these lipoproteins are endowed with... (Review)
Review
Elevated levels of low density lipoproteins (LDLs) cause atherosclerotic disease, and proteomic analyses have found that these lipoproteins are endowed with prenylcysteine lyase. This systematic review summarizes current understanding of this enzyme, now known as prenylcysteine oxidase 1 (PCYOX1), which hydrolyzes the thioether bond of prenylcysteines in the final step in the degradation of prenylated proteins, releasing hydrogen peroxide, cysteine and the isoprenoid aldehyde. Despite the high variability of the gene, no polymorphism has yet been associated with any disease. The liver, which is responsible for vehiculization of the enzyme in lipoproteins, is one of the main organs responsible for its expression, together with the gastrointestinal tract, kidney, male reproductive tissue and muscle. Moreover, although hepatic mRNA expression is sensitive to diet and hormones, the repercussion of these changes in LDLs containing PCYOX1 has not been addressed. One consequence of its elevated activity could be an increase in hydrogen peroxide, which might help to propagate the oxidative burden of LDLs, thus making PCYOX1 a potential pharmacological target and a new biomarker in cardiovascular disease.
Topics: Animals; Carbon-Sulfur Lyases; Cardiovascular Diseases; Gene Expression Profiling; Humans; Lipoproteins, LDL; Liver; Neoplasms; Neurodegenerative Diseases; Polymorphism, Single Nucleotide
PubMed: 28930587
DOI: 10.2741/4631 -
European Journal of Preventive... Mar 2017Aims Darapladib, a potent inhibitor of lipoprotein-associated phospholipase A (Lp-PLA), has not reduced risk of cardiovascular disease outcomes in recent randomized... (Review)
Review
Aims Darapladib, a potent inhibitor of lipoprotein-associated phospholipase A (Lp-PLA), has not reduced risk of cardiovascular disease outcomes in recent randomized trials. We aimed to test whether Lp-PLA enzyme activity is causally relevant to coronary heart disease. Methods In 72,657 patients with coronary heart disease and 110,218 controls in 23 epidemiological studies, we genotyped five functional variants: four rare loss-of-function mutations (c.109+2T > C (rs142974898), Arg82His (rs144983904), Val279Phe (rs76863441), Gln287Ter (rs140020965)) and one common modest-impact variant (Val379Ala (rs1051931)) in PLA2G7, the gene encoding Lp-PLA. We supplemented de-novo genotyping with information on a further 45,823 coronary heart disease patients and 88,680 controls in publicly available databases and other previous studies. We conducted a systematic review of randomized trials to compare effects of darapladib treatment on soluble Lp-PLA activity, conventional cardiovascular risk factors, and coronary heart disease risk with corresponding effects of Lp-PLA-lowering alleles. Results Lp-PLA activity was decreased by 64% ( p = 2.4 × 10) with carriage of any of the four loss-of-function variants, by 45% ( p < 10) for every allele inherited at Val279Phe, and by 2.7% ( p = 1.9 × 10) for every allele inherited at Val379Ala. Darapladib 160 mg once-daily reduced Lp-PLA activity by 65% ( p < 10). Causal risk ratios for coronary heart disease per 65% lower Lp-PLA activity were: 0.95 (0.88-1.03) with Val279Phe; 0.92 (0.74-1.16) with carriage of any loss-of-function variant; 1.01 (0.68-1.51) with Val379Ala; and 0.95 (0.89-1.02) with darapladib treatment. Conclusions In a large-scale human genetic study, none of a series of Lp-PLA-lowering alleles was related to coronary heart disease risk, suggesting that Lp-PLA is unlikely to be a causal risk factor.
Topics: 1-Alkyl-2-acetylglycerophosphocholine Esterase; Adult; Aged; Alleles; Benzaldehydes; Case-Control Studies; Coronary Disease; Female; Gene Expression Regulation; Genotype; Humans; Male; Middle Aged; Molecular Targeted Therapy; Oximes; Phospholipase A2 Inhibitors; Polymorphism, Single Nucleotide; Randomized Controlled Trials as Topic; Reference Values; Reproducibility of Results; Risk Assessment; Treatment Outcome
PubMed: 27940953
DOI: 10.1177/2047487316682186