Formaldehyde Exposure and Acute Myeloid Leukemia: A Review of the Literature

Urinary Thioproline and Thioprolinyl Glycine as Specific Biomarkers of Formaldehyde Exposure in Humans

Assessment of personal formaldehyde (FA) exposure is most commonly carried out using formate as a biomarker, as it is the major product from FA metabolism. However, formate could also have originated from the metabolism of other endogenous and exogenous substances or from dietary intake, which may give rise to overestimated results with regard to FA exposure. We have developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with an isotope-dilution method for rigorous quantitation of two major urinary FA conjugation products: thioproline (SPro) and thioprolinyl glycine (SPro-Gly), formed in the reaction between FA and endogenous cysteine or cysteinyl glycine, respectively, as marker molecules to assess personal FA exposure. Using this newly developed method, we measured the FA exposure levels in cigarette smokers, occupants of a chemistry research laboratory and typical domestic household, and visitors to a Chinese temple with a Pearson correlation coefficient greater than 0.94, showing a strong linear correlation between urinary adduct levels and the airborne FA level. It is believed that quantitation of urinary SPro and SPro-Gly may represent a noninvasive, interference-free method for assessing personal FA exposure.

Antioxidants as Protection against Reactive Oxygen Stress Induced by Formaldehyde (FA) Exposure: A Systematic Review

BACKGROUND AND OBJECTIVES

Formaldehyde induces oxidative stress and is carcinogenic, particularly squamous cell carcinoma of the nasopharyngeal area. Around us, in exhaust gases, cigarette smoke, and various industrial products, FA primarily affects the respiratory tract and other organs like the cornea, liver, kidneys, brain, and cardiovascular system. This study aims to determine if antioxidants can mitigate FA's harmful effects.

MATERIALS AND METHODS

Several databases, including PubMed, Science Direct, Springer, and Wiley, were systematically searched. Research publications on antioxidants mitigating FA-induced oxidative damage were included, but reviews and articles lacking complete texts were excluded. SYRCLE's risk of bias tool for animal studies has been used. Tables were used for data synthesis. Out of 8790 articles, 35 publications detailing tissue homogenate for biochemical analysis, standard hematoxylin-eosin staining, and immunohistochemistry markers for histopathological and immunohistochemical diagnosis were selected. Most studies were case-control studies, utilizing rat or mouse models. Additionally, one cohort study on industrial workers was analyzed.

CONCLUSIONS

Antioxidants, including plant extracts, vitamins, and pigments, can prevent or heal FA-induced lesions. However, human studies, particularly biopsies, remain challenging, and animal trials are limited. Further research is needed to confirm FA's long-term effects and optimize antioxidant dosages.

Residential exposure to air pollution and incidence of leukaemia in the industrial area of Viadana, Northern Italy

BACKGROUND

Exposure to air pollution has been proposed as one of the potential risk factors for leukaemia. Work-related formaldehyde exposure is suspected to cause leukaemia.

METHODS

We conducted a nested register-based case-control study on leukaemia incidence in the Viadana district, an industrial area for particleboard production in Northern Italy. We recruited 115 cases and 496 controls, frequency-matched by age, between 1999 and 2014. We assigned estimated exposures to particulate matter (PM10, PM2.5), nitrogen dioxide (NO2), and formaldehyde at residential addresses, averaged over the susceptibility window 3rd to 10th year prior to the index date. We considered potential confounding by sex, age, nationality, socio-economic status, occupational exposures to benzene and formaldehyde, and prior cancer diagnoses.

RESULTS

There was no association of exposures to PM10, PM2.5, and NO2 with leukaemia incidence. However, an indication of increased risk emerged for formaldehyde, despite wide statistical uncertainty (OR 1.46, 95%CI 0.65-3.25 per IQR-difference of 1.2 μg/m3). Estimated associations for formaldehyde were higher for acute (OR 2.07, 95%CI 0.70-6.12) and myeloid subtypes (OR 1.79, 95%CI 0.64-5.01), and in the 4-km buffer around the industrial facilities (OR 2.78, 95%CI 0.48-16.13), although they remained uncertain.

CONCLUSIONS

This was the first study investigating the link between ambient formaldehyde exposure and leukaemia incidence in the general population. The evidence presented suggests an association, although it remains inconclusive, and a potential significance of emissions related to industrial activities in the district. Further research is warranted in larger populations incorporating data on other potential risk factors.

Assessment of associations between inhaled formaldehyde and lymphohematopoietic cancer through the integration of epidemiological and toxicological evidence with biological plausibility

Formaldehyde is recognized as carcinogenic for the portal of entry sites, though conclusions are mixed regarding lymphohematopoietic (LHP) cancers. This systematic review assesses the likelihood of a causal relationship between formaldehyde and LHP cancers by integrating components recommended by NASEM. Four experimental rodent bioassays and 16 observational studies in humans were included following the implementation of the a priori protocol. All studies were assessed for risk of bias (RoB), and meta-analyses were conducted on epidemiological studies, followed by a structured assessment of causation based on GRADE and Bradford Hill. RoB analysis identified systemic limitations precluding confidence in the epidemiological evidence due to inadequate characterization of formaldehyde exposure and a failure to adequately adjust for confounders or effect modifiers, thus suggesting that effect estimates are likely to be impacted by systemic bias. Mixed findings were reported in individual studies; meta-analyses did not identify significant associations between formaldehyde inhalation (when measured as ever/never exposure) and LHP outcomes, with meta-SMRs ranging from 0.50 to 1.51, depending on LHP subtype. No associations with LHP-related lesions were reported in reliable animal bioassays. No biologically plausible explanation linking the inhalation of FA and LHP was identified, supported primarily by the lack of systemic distribution and in vivo genotoxicity. In conclusion, the inconsistent associations reported in a subset of the evidence were not considered causal when integrated with the totality of the epidemiological evidence, toxicological data, and considerations of biological plausibility. The impact of systemic biases identified herein could be quantitatively assessed to better inform causality and use in risk assessment.

Interventional probability of causation (IPoC) with epidemiological and partial mechanistic evidence: benzene vs. formaldehyde and acute myeloid leukemia (AML)

INTRODUCTION

Causal epidemiology for regulatory risk analysis seeks to evaluate how removing or reducing exposures would change disease occurrence rates. We define interventional probability of causation (IPoC) as the change in probability of a disease (or other harm) occurring over a lifetime or other specified time interval that would be caused by a specified change in exposure, as predicted by a fully specified causal model. We define the closely related concept of causal assigned share (CAS) as the predicted fraction of disease risk that would be removed or prevented by a specified reduction in exposure, holding other variables fixed. Traditional approaches used to evaluate the preventable risk implications of epidemiological associations, including population attributable fraction (PAF) and the Bradford Hill considerations, cannot reveal whether removing a risk factor would reduce disease incidence. We argue that modern formal causal models coupled with causal artificial intelligence (CAI) and realistically partial and imperfect knowledge of underlying disease mechanisms, show great promise for determining and quantifying IPoC and CAS for exposures and diseases of practical interest.

METHODS

We briefly review key CAI concepts and terms and then apply them to define IPoC and CAS. We present steps to quantify IPoC using a fully specified causal Bayesian network (BN) model. Useful bounds for quantitative IPoC and CAS calculations are derived for a two-stage clonal expansion (TSCE) model for carcinogenesis and illustrated by applying them to benzene and formaldehyde based on available epidemiological and partial mechanistic evidence.

RESULTS

Causal BN models for benzene and risk of acute myeloid leukemia (AML) incorporating mechanistic, toxicological and epidemiological findings show that prolonged high-intensity exposure to benzene can increase risk of AML (IPoC of up to 7e-5, CAS of up to 54%). By contrast, no causal pathway leading from formaldehyde exposure to increased risk of AML was identified, consistent with much previous mechanistic, toxicological and epidemiological evidence; therefore, the IPoC and CAS for formaldehyde-induced AML are likely to be zero.

CONCLUSION

We conclude that the IPoC approach can differentiate between likely and unlikely causal factors and can provide useful upper bounds for IPoC and CAS for some exposures and diseases of practical importance. For causal factors, IPoC can help to estimate the quantitative impacts on health risks of reducing exposures, even in situations where mechanistic evidence is realistically incomplete and individual-level exposure-response parameters are uncertain. This illustrates the strength that can be gained for causal inference by using causal models to generate testable hypotheses and then obtaining toxicological data to test the hypotheses implied by the models-and, where necessary, refine the models. This virtuous cycle provides additional insight into causal determinations that may not be available from weight-of-evidence considerations alone.

Standardization of honey as a tissue fixative for histopathology: A morphometric study

Background

Tissue fixation is a crucial step to preserve the tissues in a life-like state with minimal disruption to its cellular and chemical composition for histopathological examination. The search for an effective alternate tissue fixative to the routinely used formaldehyde has gained interest as constant exposure to formaldehyde has proven to be toxic. Honey, an organic substance with high acidity and hygroscopic nature, exhibits tissue fixative properties and has been used in the present study. The present study aimed to standardize honey as a tissue fixative for histopathology by comparing it with formalin.

Materials and Methods

In vitro study Oral tissue samples of goat were fixed in 10% honey and 10% formalin solution, respectively, for 24-48 h, followed by routine tissue processing and microscopic examination of 37 slides per group. 2200 epithelial cells (1100 per group) were selected for the computer-aided morphometric image analysis (Fiji-Image J) by three observers. Cell area (CA), cell perimeter (CP), nuclear area (NA), nuclear perimeter (NP), cytoplasmic area (Cyt A), and nuclear-cytoplasmic ratio were the parameters studied. Mann-Whitney U-test (STATA/IC version 16) for inter-group comparison was done and P < 0.05 was considered statistically significant.

Results

The probability of epithelial cells in the honey-fixed group to have greater NA, NP, and N/C ratio was about 50%-60%. The probability of epithelial cells in formalin-fixed tissues to have greater CA, CP, and Cyt A was about 70%.

Conclusion

Honey is a better nuclear fixative than formalin. Cytoplasmic shrinkage of epithelial cells should be taken into consideration while fixing tissues with honey.

The Anti-Cancer Effect of Cinnamon Aqueous Extract: A Focus on Hematological Malignancies

Cinnamon is an evergreen and tropical plant of the family Lauraceae, growing particularly in Sri Lanka, whose aqueous extract has been tested in different studies to evaluate its possible use as an anti-cancer compound. Both in vitro and in vivo experiments seem to confirm that it acts on various cellular pathways, contributing to down-regulating the activity of molecules that stimulate the proliferation and survival of cells such as the transcription factors NF-KB and AP-1, COX-2, dihydrofolate reductase and pro-angiogenic substances such as VEGF, while up-regulating the function of immune cells against tumors, such as cytotoxic CD8+ T cells. In hematological malignancies, aqueous cinnamon extract has been studied in order to understand if it is possible to count on its help, alone or in combination with traditional drugs such as doxorubicin, to treat patients. The aim of our work is to investigate results from in vitro and in vivo studies about the possible anti-cancer effect of aqueous cinnamon extract in hematological malignancies and the different pathways involved in its action. The possibility of using cinnamon extract in clinical practice is discussed; even if its use could appear very interesting, more studies are necessary to clear the real potentiality of this substance in cancer.

Relationship between formaldehyde exposure, respiratory irritant effects and cancers: a review of reviews

OBJECTIVES

Formaldehyde is an organic compound used in the production of resins, paper, wood plywood, solvents and cleaning products. Formaldehyde is also present when tobacco is smoked. Formaldehyde has been defined as an irritant and is classified as a human carcinogen by the International Agency for Research on Cancer. The purpose of this study was to demonstrate the following two distinct correlations: (1) the association between formaldehyde exposure and development of irritant diseases affecting the respiratory tract, mainly asthma; and (2) the association between formaldehyde exposure and development of neoplastic diseases.

STUDY DESIGN

This was an umbrella review.

METHODS

A search was conducted in the three main electronic databases of scientific literature: PubMed, Scopus and Web of Science. The search included systematic reviews and meta-analyses published in the previous 10 years. Initially, titles and abstracts of retrieved articles were evaluated, then full-text assessments of selected articles took place. Data extraction and quality assessment were performed according to Assessing the Methodological Quality of Systematic Reviews (AMSTAR) score.

RESULTS

A total of 630 articles were initially collected. Nine articles concerning the association between formaldehyde exposure and asthma were included in the present review, and the majority of these reported good association. In addition, 27 articles investigating the association between formaldehyde exposure and neoplastic diseases were included in the review. These studies showed that nasopharyngeal cancer and leukaemia were the most represented neoplastic diseases; however, only a weak association was reported between formaldehyde exposure and cancer.

CONCLUSIONS

Although the studies included in this review did not show a strong association between exposure to formaldehyde and irritant or neoplastic diseases, the World Health Organisation recommends that levels of formaldehyde do not exceed the threshold value of 0.1 mg/m³ (0.08 ppm) for a period of 30 min. It is recommended that preventive measures, such as ventilation in workplaces with high exposure to formaldehyde and environmental monitoring of formaldehyde concentrations, are implemented.

Ambient formaldehyde and mortality: A time series analysis in China

The potential health impact of low-level ambient formaldehyde has been historically overlooked. We conducted a two-stage time series analysis to investigate associations between ambient formaldehyde and daily nonaccidental, circulatory, and respiratory mortality and six subtypes based on 5,325,585 deaths in 275 Chinese counties between 2013 and 2018 and estimated a concentration-response curve to identify overall associations. After controlling for confounders from meteorological factors, air pollutants, time trend, and day of the week effect, with a 1-part per billion (ppb) increase in the daily concentration of formaldehyde on lag0 day, we found that mortality risks in nonaccidental, circulatory, and respiratory diseases increased by 0.36%, 0.36% and 0.41%, respectively. The curve indicated a possible threshold concentration at approximately 5 ppb for significant impact on nonaccidental and circulatory diseases. We suggest that ambient formaldehyde may represent a potential threat to public health and needs further investigation to support timely pollution regulation and health protection.

Assessment of formaldehyde exposures under contemporary embalming conditions in U.S. funeral homes

The funeral service profession has used formaldehyde-containing embalming solutions for the preparation of decedents since the early 1900s. The available literature regarding funeral director exposure to formaldehyde largely consists of data collected prior to 2000, with most studies reporting task-length exposure concentrations rather than full-shift time-weighted average concentrations. As formaldehyde undergoes review in the U.S. Environmental Protection Agency Toxic Substances Control Act (TSCA) risk evaluation process, accurately characterizing long-term exposure potential in this profession is critical. This study presents passive badge sampling and air change rate measurement results conducted at 13 funeral home locations across the United States. Full-shift (approximately 8-hr) samples were collected on one embalmer per day in each funeral home and on one occupational non-user (ONU), e.g., a receptionist. Additionally, task-length samples were collected during each embalming that occurred during the shift, were one to occur. Full-shift concentrations ranged from 0.007 to 1.1 ppm and 0.007 to 0.042 ppm for embalmers and ONUs, respectively. Task-length formaldehyde concentrations ranged from 0.058 to 1.4 ppm, with the average embalming taking 72.8 min to complete. Air change rates in the preparation rooms ranged from 2.8 to 28.3 air changes per hour; however, no correlation between task-length formaldehyde concentrations and air change rate was observed. Following empirical data collection, a Monte Carlo analysis of estimated annual 8-hr time-weighted average (TWA) exposure was conducted to determine the potential exposure distribution for embalmers employed at private funeral homes. Inputs to the simulation were derived from responses to a National Funeral Directors Association survey and from empirical measurements collected during the study. With respect to the reconstructed 8-hr TWAs, the median 8-hr TWA was 0.037 ppm, with 93.6% of the predicted concentrations below 0.1 ppm. This study provides a robust characterization of contemporary formaldehyde exposures in the funeral service profession. Further, it provides a strategy for interpreting the results along with surveyed responses regarding embalming frequency to better inform risks associated with formaldehyde exposure in this profession.

Analysis of Differentially Expressed Proteins and Modifications Induced by Formaldehyde Using LC-MS/MS

Formaldehyde (FA) is a toxic compound that is considered to have a carcinogenic effect due to its damage to biological macromolecules. However, the influence of FA at the protein level remains to be explored. Here, we used LC-MS/MS to identify the differentially expressed proteins and modifications to proteins between FA-treated and untreated HeLa cells. Among 2021 proteins identified, 196 proteins were significantly down-regulated and 152 up-regulated. The differentially expressed proteins were further analyzed using bioinformatics tools for annotating the characterization of their localizations and functions. To evaluate the interaction of FA with proteins, we performed proteomic analysis for a mass shift of 12 Da on the side chains of lysine, cysteine and tryptophan, which are induced by FA as noticeable signals. We identified the modified proteins and sites, suggesting direct interaction between FA and proteins. Motif analysis further showed the characterization of amino acid sequences that react with FA. Cluster analysis of the modified proteins indicated that the FA-interacting networks are mostly enriched in the nuclei, ribosomes and metabolism. Our study presents the influence of FA on proteomes and modifications, offering a new insight into the mechanisms underlying FA-induced biological effects.

Circular RNA-CDR1as is involved in lung injury induced by long-term formaldehyde inhalation

OBJECTIVE

Formaldehyde (FA) is known to induce lung injury, but the underlying molecular mechanism remains largely unclear. CDR1as is an important member of the circular RNAs (circRNAs) family and functions as miRNA sponges with gene-regulatory potential. Our earlier circRNA microarray data showed CDR1as was highly expressed in lung tissue exposed to FA. However, the mechanism of circRNA-CDR1as mediates the FA-exposed lung injury is still unclear. This study aimed to explore the role of CDR1as in lung injury.

MATERIALS AND METHODS

In this study, FA was inhaled at doses of 0.5, 2.46, and 5 mg/m3, respectively. After exposure 8 weeks, lung histopathological examination, lung injury score, and IL-1β in bronchoalveolar lavage fluid (BALF) were determined. The expressions of CDR1as, rno-miR-7b and Atg7 were detected and the potential interaction of circRNA/miRNA/mRNA was predicted by bioinformatics analysis, including drawing circRNA/miRNA/mRNA interaction network, GO and KEGG analysis.

RESULTS

Our results indicated FA inhalation upregulated the expression of CDR1as in lung tissues in a dose-dependent manner while the expression of rno-miR-7b decreased and Atg7 increased. Moreover, the alteration of CDR1as was positively correlated with lung injury.

DISCUSSION AND CONCLUSIONS

CircRNA/miRNA/mRNA prediction further explained the possible effect mechanisms of CDR1as. These data implicated that CDR1as might be a critical regulator involved in lung injury induced by FA.

Association between CYP2B6 c.516G >T variant and acute leukaemia: A protocol for systematic review and meta-analysis

BACKGROUND

Acute leukemia (AL) is a kind of malignant tumor of hematopoietic system. A number of studies have suggested that Single Nucleotide Polymorphisms are significantly associated with risk of AL. Present study performs meta-analysis to evaluate the association between CYP2B6 c.516G>T variant and AL risk.

METHODS

Databases including PubMed, EMBASE, Chinese National Knowledge Infrastructure (CNKI), and Wanfang were searched for literatures to September 30, 2019, both in English and Chinese. Relative risk and its 95% confidence intervals were used to assess the associations. Statistical analyses of this meta-analysis were conducted by using STATA 13.0. software.

RESULTS

A total of 7 studies, including 1038 cases and 1648 controls, were analyzed. Our results indicated that CYP2B6 c.516G>T variant was significantly related to an increased the risk of AL under dominant model, recessive model, homozygote model, and allelic model. In addition, subgroup analyses were also performed by disease classification, country, and study design. No significant associations were obtained between CYP2B6 c.516G>T variant and the risk of AL under the recessive model in the design of hospital-based (relative risk = 0.98; 95% confidence interval: 0.95-1.01; P  = 0.118).

CONCLUSION

Our meta-analysis indicated that the CYP2B6 variant is significantly associated with AL risk, in which CYP2B6 c.516G>T is related to an increased risk of AL.

Formaldehyde in Hospitals Induces Oxidative Stress: The Role of GSTT1 and GSTM1 Polymorphisms

Despite the toxicity and health risk characteristics of formaldehyde (FA), it is currently used as a cytological fixative and the definition of safe exposure levels is still a matter of debate. Our aim was to investigate the alterations in both oxidative and inflammatory status in a hospital working population. The 68 workers recruited wore a personal air-FA passive sampler, provided a urine sample to measure 15-F_2t-Isoprostane (15-F_2t-IsoP) and malondialdehyde (MDA) and a blood specimen to measure tumour necrosis factor α (TNFα). Subjects were also genotyped for GSTT1 (Presence/Absence), GSTM1 (Presence/Absence), CYP1A1 exon 7 (A > G), and IL6 (−174, G > C). Workers were ex post split into formalin-employers (57.3 μg/m³) and non-employers (13.5 μg/m³). In the formalin-employers group we assessed significantly higher levels of 15-F_2t-IsoP, MDA and TNFα (<0.001) in comparison to the non-employers group. The air-FA levels turned out to be positively correlated with 15-F_2t-IsoP (p = 0.027) and MDA (p < 0.001). In the formalin-employers group the MDA level was significantly higher in GSTT1 Null (p = 0.038), GSTM1 Null (p = 0.031), and CYP1A1 exon 7 mutation carrier (p = 0.008) workers, compared to the wild type subjects. This study confirms the role of FA in biomolecular profiles alterations, highlighting how low occupational exposure can also result in measurable biological outcomes.

Controversy around parabens: Alternative strategies for preservative use in cosmetics and personal care products

Parabens usage as preservatives in cosmetics and personal care products have been debated among scientists and consumers. Parabens are easy to production, effective and cheap, but its safety status remains controversial. Other popular cosmetics preservatives are formaldehyde, triclosan, methylisothiazolinone, methylchloroisothiazolinone, phenoxyethanol, benzyl alcohol and sodium benzoate. Although their high antimicrobial effectiveness, they also exhibit some adverse health effects. Lately, scientists have shown that natural substances such as essential oils and plant extracts present antimicrobial potential. However, their use in cosmetic is a challenge. The present review article is a comprehensive summary of the available methods to prevent microbial contamination of cosmetics and personal care products, which can allow reducing the use of parabens in these products.

Minimizing formaldehyde exposure in a hospital pathology laboratory

BACKGROUND

The safety and health of healthcare workers employed in pathology laboratories and exposed to formaldehyde (FA) is a matter of concern worldwide, as several health effects have been observed in workers resulting from exposure to FA, both short and long-term.

OBJECTIVE

The study was aimed to describe the strategy implemented in a hospital pathology laboratory to minimize workers' exposure to FA through interventions to working environment and workforce.

METHODS

The NIOSH 2016 method for detecting gaseous FA was adopted to perform personal and area active sampling of FA. The samples were subsequently analyzed by High Performance Liquid Chromatography. The exposure to FA was measured before and after improvement interventions.

RESULTS

The pre-intervention step showed FA levels exceeding the threshold limit values (TLV) established by ACGIH, both the time-weighted average (TLV-TWA) and short term exposure limit (TLV-STEL); after the improvement interventions, the median concentrations of personal and area FA sampling were respectively of 0.025 ppm (Range = 0.023-0.027) and 0.023 ppm (Range = 0.022-0.028) and significantly lower than pre-intervention step (p < 0.05) and below the TLV-TWA and TLV-STEL established by ACGIH.

CONCLUSIONS

In our study the workers' involvement in the risk management of FA exposure together with engineering improvements revealed a strategic way to minimize the FA pollution in the studied laboratory. Healthcare companies should consider the need to ensure the workers' participation in the management of occupational hazards, including FA, to reach the goal of healthy workplaces.

Toxic effects of formaldehyde and the protective effect of docosahexaenoic acid in Drosophila

Formaldehyde (FA) is a commercially important chemical applied in industry and scientific research. However, FA has a distinct impact on learning and memory. Although the mechanisms of FA toxicity have been well studied, additional research is required to establish the mechanisms of neuroprotection in cases of FA exposure. Docosahexaenoic acid (DHA) is a polyunsaturated fatty acid with a variety of health benefits, including the enhancement of learning and memory. In this study, we investigated the neuroprotective effects of DHA in Drosophila melanogaster that had ingested FA. Our data suggested that DHA enhanced reproductive processes, leading to an increase in the number of eggs, larvae, and adults. Surprisingly, we found that DHA had a mild protective effect against FA-induced impairments in learning and memory.

Application of biosynthesized metal nanoparticles in electrochemical sensors

Recently, the development of eco-friendly, cost-effective and reliable methods for synthesis of metal nanoparticles has drawn a considerable attention. The so-called green synthesis, using mild reaction conditions and natural resources as plant extracts and microorganisms, has established as a convenient, sustainable, cheap and environmentally safe approach for synthesis of a wide range of nanomaterials. Over the past decade, biosynthesis is regarded as an important tool for reducing the harmful effects of traditional nanoparticle synthesis methods commonly used in laboratories and industry. This review emphasizes the significance of biosynthesized metal nanoparticles in the field of electrochemical sensing. There is increasing evidence that green synthesis of nanoparticles provides a new direction in designing of cost-effective, highly sensitive and selective electrode-catalysts applicable in food, clinical and environmental analysis. The article is based on 157 references and provided a detailed overview on the main approaches for green synthesis of metal nanoparticles and their applications in designing of electrochemical sensor devices. Important operational characteristics including sensitivity, dynamic range, limit of detection, as well as data on stability and reproducibility of sensors have also been covered.

LncRNA SNHG16 Regulates the Progress of Acute Myeloid Leukemia Through miR183-5p-FOXO1 Axis

Purpose

At present, there is a lack of precise knowledge on acute myeloid leukemia (AML) at the molecular level, and understanding its occurrence at the genetic level is conducive to the development of targeted therapies. Therefore, in this study the relationship between the lncRNA SNHG1 –miR183-5p–FOXO1 axis and AML was explored.

Methods

Expression of lncRNA SNHG16 and miR183-5p was quantified by quantitative real-time PCR, and the level of FOXO1 and other proteins was measured by Western blot. Expression vectors of lncRNA SNHG16, miR183-5p, and FOXO1 were constructed to assess effects of the three on cell proliferation and apoptosis. MTT reduction assays were employed for cell proliferation, flow cytometry for cell cycle and apoptosis, and dual luciferase–reporter assays for the targeting relationship between lncRNA SNHG16 and miR183-5p and miR183-5p and FOXO1.

Results

lncRNA SNHG16 was highly expressed in peripheral blood/leukemia cell lines of patients with AML compared with normal human peripheral blood/peripheral blood mononuclear cells. miR183-5p was the target of lncRNA SNHG16 and FOXO1 the target gene of miR183-5p rather than lncRNA SNHG16. Absence of lncRNA SNHG16 led to upregulation of miR183-5p, promotion of apoptosis, and inhibition of proliferation. Suppression of miR183-5p accelerated cell proliferation and hindered apoptosis. miR183-5p negatively regulated FOXO1, and FOXO1 promoted proliferation and inhibited apoptosis. Inhibition of miR183-5p counteracted the changes caused by lncRNA SNHG16 absence.

Conclusion

lncRNA SNHG16 regulates the progress of AML via the miR183-5p–FOXO1 axis.

Associations between observed formaldehyde concentrations and smoking, environmental tobacco smoke, and self-reported cancers and asthma: data for US children, adolescents, and adults

For the first time, the National Health and Nutrition Examination Survey (NHANES) released data on hemoglobin adducts of formaldehyde (HCHO) in public domain for US children aged 6-11 years, adolescents aged 12-19 years, and adults aged > = 20 years for 2015-2016. This study was undertaken to evaluate the associations between concentrations of HCHO in whole blood and smoking, exposure to environmental tobacco smoke (ETS), and self-reported diagnoses of cancers and asthma. Adult smokers were found to have higher adjusted concentrations of HCHO than nonsmokers (127.7 vs. 125.1 pmol/g Hb, p = 0.02). Exposure to ETS was not found to affect the adjusted concentrations of HCHO. No associations were observed between HCHO concentrations and self-reported diagnosis of "ever" cancer as well as self-reported presence of asthma at the time of participation in NHANES. HCHO concentrations were not found to differ across genders and racial/ethnic groups for children and adolescents. Among adults, non-Hispanic blacks (120.0 pmol/g Hb) had lower adjusted concentrations (p < = 0.01) of HCHO than non-Hispanic whites (128.8 pmol/g Hb), Mexican Americans (129.4 pmol/g Hb), other Hispanics (130.3 pmol/g Hb), and non-Hispanic Asians (127.9 pmol/g Hb). In conclusion, self-reported diagnoses of cancer and asthma were not found to be associated with observed concentrations of HCHO in whole blood.

Formaldehyde toxicity reports from in vitro and in vivo studies: a review and updated data

Formaldehyde (FA) is a xenobiotic air pollutant and its universal distribution causes a widespread exposure to humans. This review aimed to bring updated information concerning FA toxicity in humans and animals based on in vitro and in vivo studies from 2013 to 2019. Researches were carried out in Pubmed, Scopus, and Science Direct databases to determine the effects of FA exposure on inflammation, oxidative stress and genotoxicity in experimental studies with animals (rats and mice) and humans. Besides, in vitro studies assessing FA cytotoxicity focusing on cell viability and apoptosis in different cell line cultures were reviewed. Studies with humans gave evidence regarding significant deleterious effects on health associated to chronic FA occupational exposure. Evaluations carried out in experimental studies showed toxic effects on different organs as lung, upper respiratory tract, bone marrow and brain as well as in cells. In summary, this study demonstrates that knowing the mechanisms underlying FA toxicity is essential to understand the deleterious effects that this xenobiotic causes on biological systems.