Nitrosamine and related food intake and gastric and oesophageal cancer risk: A systematic review of the epidemiological evidence

Effects of Animal-Based and Plant-Based Nitrates and Nitrites on Human Health: Beyond Nitric Oxide Production

Nitrate (NO3) and nitrite (NO2) are important nitrogen compounds that play a vital role in the nitrogen cycle, contributing to plant nutrition and broader ecological functions. Nitrates are produced from nitric acid (HNO3), while nitrites come from nitrous acid (HNO2). These substances are commonly found in the environment, especially in food and water, due to contamination from both human and natural sources. Human activities are major contributors to the high levels of nitrates found in water, leading to environmental pollution. Although nitrogen is crucial for plant growth, excessive fertilizer use has caused ecological disruptions. In plants, nitrates tend to accumulate primarily in the leaves of non-leguminous crops, such as leafy vegetables, which are known for their high nitrate content. Furthermore, nitrates and nitrites are added to animal-based foods, especially processed meats and cheeses, to prevent bacterial growth, slow spoilage, and improve flavor and color. The concentration of these compounds in food can vary due to different factors like farming practices, climate, soil conditions, and food production methods. This review seeks to examine the differences between the plant-based and animal-based sources of these compounds and assess their potential impact on human health, considering also the paradigm that goes beyond nitric oxide production.

Fabrication of Cu@Ag core-shell/nafion/polyalizarin: Applications to simultaneous electrocatalytic oxidation and reduction of nitrite in water samples

In this study, a Cu@Ag core-shell was synthesized using a co-precipitation method. To create a new electrochemical sensor, a Cu@Ag core-shell with conductive polymers such as polyalizarin yellow R (PA) and Nafion (Nf) was immobilized on the surface of a glassy carbon electrode (Cu@Ag-Nf/PA/GCE). X-ray diffraction analysis (XRD), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR) techniques were employed to characterize the Cu@Ag-Nf/PA/GCE. This modified electrode was used to measure nitrite ions in the water samples. Electrochemical analysis of nitrite was conducted using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) methods. For the first time, the results indicated that the Cu@Ag-Nf/PA nanocomposite demonstrated excellent performance in simultaneously electrocatalyzing oxidation at two specific potentials (0.17V and 0.98V denoted as OX1 and OX2 peaks) and one reduction potential (-0.42 V as a Red peak) for nitrite ions. This research showed various advantages, including applications in linear ranges, sensitivities, and detection limits in three potential areas (OX1, OX2, and Red) by elucidating the mechanism of action of the new electrode for detecting nitrite ions in water samples.

Assessing Variability in Children's Exposure to Contaminants in Food: A Longitudinal Non-Targeted Analysis Study in Miami, Florida

Food is essential for human survival; however, food can be an important route of exposure to contaminants. This study investigated the presence and distribution of anthropogenic contaminants in food consumed by families with small children in South Florida, United States, evaluating seasonal and socio-economic variabilities in chemical composition. QuEChERS protocols, followed by non-targeted analysis (NTA) using an LC-Orbitrap HRMS system, were used for the comprehensive screening of organic contaminants. The compounds were annotated and identified with the Compound Discoverer (CD) software, and contaminant distributions were analyzed using boxplots and Principal Component Analysis (PCA). The results showed significant seasonal and socio-economic differences in contaminant distributions (p < 0.05). In the wet season, a predominance of polymers and surfactants, such as dodecanedioic acid and N-dodecylacrylamide, were found in food, which might be due to increased transport of industrial pollutants during increased precipitation, while plasticizers (e.g., bis(2-ethylhexyl) phthalate) and drugs (e.g., warfarin) were more prevalent during the dry season, which could be related to less dilution effects in this period. A higher abundance of 1-nitrosopiperidine, present in cured meats, was noted in food from upper socio-economic classes, while the lower class showed higher abundance of benzocaine, a common topical anesthetic.

Evaluation of Genotoxic Effects of N-Methyl-N-Nitroso-Urea and Etoposide on the Differentiation Potential of MSCs from Umbilical Cord Blood and Bone Marrow

The present study investigates the influence of nitrosamines and etoposide on mesenchymal stromal cells (MSCs) in a differentiation state- and biological age-dependent manner. The genotoxic effects of the agents on both neonatal and adult stem cell populations after treatment, before, or during the course of differentiation, and the sensitivity of the different MSC types to different concentrations of MNU or etoposide were assessed. Hereby, the multipotent differentiation capacity of MSCs into osteoblasts, adipocytes, and chondrocytes was analyzed. Our findings reveal that while all cell types exhibit DNA damage upon exposure, neonatal CB-USSCs demonstrate enhanced resistance to genotoxic damage compared with their adult counterparts. Moreover, the osteogenic differentiation of MSCs was more susceptible to genotoxic damage, whereas the adipogenic and chondrogenic differentiation potentials did not show any significant changes upon treatment with genotoxin. Furthermore, we emphasize the cell-specific variability in responses to genotoxic damage and the differences in sensitivity and reaction across different cell types, thus advocating the consideration of these variabilities during drug testing and developmental biological research.

Effect of carnosine on nitrosamine formation in gastric-simulated aqueous and lipid environments

BACKGROUND

Nitrite salts are frequently utilized as meat additives to improve the quality and safety of processed meat products. However, these salts are associated with the formation of carcinogenic nitrosamines. Given its potential regulating effect on the formation of intermediate molecules, such as nitric oxide, it is hypothesized that carnosine, a meat constituent possessing antioxidant activity and other multiple health benefits, could dampen the formation of nitrosamines. The current study therefore assessed the effect of carnosine on nitrosamine formation in both a monophasic aqueous system and a biphasic water-lipid system simulating a gastric environment.

RESULTS

In the monophasic system, relatively high levels of carnosine were required to significantly reduce the formation of different species of nitrosamine compared with the control (no carnosine). While higher levels of some nitrosamines were generated in both phases of the biphasic system, low carnosine concentrations significantly suppressed nitrosamine formation in the aqueous phase, while in the lipid phase, intermediate levels of carnosine were required. At higher carnosine levels, further reduction in nitrosamines was observed in the lipid phase.

CONCLUSIONS

This study demonstrates the capacity of carnosine to reduce nitrosamine formation in aqueous and lipid environments and suggests the potential of dietary carnosine to lower the risks associated with the consumption of processed meat products. © 2024 His Majesty the King in Right of Canada and The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.

Chronic daily intake, probabilistic carcinogenic risk assessment and multivariate analysis of volatile N-nitrosamines in chicken sausages

Volatile N-nitrosamines (VNAs) are probably and possibly carcinogenic compounds to humans and widely found in processed meat products. In this study, the dietary exposure distribution and probabilistic cancer risk for main VNAs (N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosomethylethylamine, N-nitrosopiperidine, N-nitrosodibutylamine, and N-nitrosodi-n-propylamine) were calculated by Monte Carlo simulation (MCS). The lowest and highest mean concentrations of these six NAs were related to NDBA and NDEA as 0.350 and 2.655 μg/kg, respectively. In the 95th percentile, chronic daily intake of total VNAs for children (3-14 years) and adults (15-70 years) were calculated to be 2.83 × 10-4 and 5.90 × 10-5 mg/kg bw/day, respectively. The cancer risk caused by the consumption of chicken sausages was less than 10-4, indicating low concern for the Iranian population. According to principal component analysis and heat map results, NDEA, NPIP and frying showed a positive correlation, highlighting that the variables follow a similar trend.

Phosphate and Nitrate Electrochemical Sensor Based on a Bifunctional Boron-Doped Diamond Electrode

Phosphorus and nitrogen are important elements in both environmental cycles and biological growth, and their imbalance can lead to serious environmental and biological problems. It is important to be able to monitor the concentration of nitrate and phosphate in the water online. In this paper, a bifunctional boron-doped diamond (BDD) electrode with repeatable electrochemical renewal and modification ability has been developed and used as a shared working electrode for the determination of nitrate and phosphate. First, phosphate can be detected directly with a bare BDD electrode. After a thin copper (Cu) layer was electrodeposited on the BDD electrode, nitrate could be determined. The copper layer is then removed under a positive voltage, and the BDD electrode is renewed and can be used again for phosphate detection. This method enables the detection of both phosphate and nitrate while also improving the stability and repeatability through the renewal of the electrode surface. The segmented linear ranges for phosphate were 0.02-0.4 and 0.4-3 mg/L with a detection limit of 0.004 mg/L. The sensor detected nitrate in a wide concentration range, with segmented linear relationships in the ranges of 0.07-3 and 3-100 mg/L, with a detection limit of 0.065 mg/L. The electrochemical sensor based on the BDD electrode has a good reproducibility for phosphate and nitrate detection. The relative standard deviation (RSD) values of the current responses were 2.98, 2.79, 1.66, 1.81, and 1.23%, respectively, for 35 consecutive tests in 0.05, 0.2, 0.5, 1, and 1.5 mg/L phosphate solution. The RSD values of the current responses were 2.00, 0.97, and 1.03%, respectively, for 25 consecutive tests in 5, 7, and 10 mg/L nitrate solution.

N-Nitrosamines: a potential hazard in processed meat products

Nitrite, nitrate, and their salts are added to processed meat products to improve color, flavor, and shelf life and to lower the microbial burden. N-Nitrosamine compounds are formed when nitrosing agents (such as secondary nitrosamines) in meat products interact with nitrites and nitrates that have been added to the meat. With the consumption of such meat products, nitrosation reactions occur in the human body and N-nitrosamine formation occurs in the gastrointestinal tract. Despite the benefits nitrites and nitrates have on food, their tendency to create nitrosamines and an increase in the body's nitrous amine load presents health risks. The inclusion of nitrosamine compounds in possible and probable carcinogen classes according to the International Agency for Research on Cancer requires a re-examination of the literature review on processed meat products. This article evaluates the connections between various cancer types and nitrosamines found in processed meat products. © 2023 Society of Chemical Industry.

Risk characterization of N-nitrosodimethylamine in pharmaceuticals

Since 2018, N-nitrosodimethylamine (NDMA) has been a reported contaminant in numerous pharmaceutical products. To guide the pharmaceutical industry, FDA identified an acceptable intake (AI) of 96 ng/day NDMA. The approach assumed a linear extrapolation from the Carcinogenic Potency Database (CPDB) harmonic-mean TD50 identified in chronic studies in rats. Although NDMA has been thought to act as a mutagenic carcinogen in experimental animals, it has not been classified as a known human carcinogen by any regulatory agency. Humans are exposed to high daily exogenous and endogenous doses of NDMA. Due to the likelihood of a threshold dose for NDMA-related tumors in animals, we believe that there is ample scientific basis to utilize the threshold-based benchmark dose or point-of-departure (POD) approach when estimating a Permissible Daily Exposure limit (PDE) for NDMA. We estimated that 29,000 ng/kg/day was an appropriate POD for calculating a PDE. Assuming an average bodyweight of 50 kg, we expect that human exposures to NDMA at doses below 5800 ng/day in pharmaceuticals would not result in an increased risk of liver cancer, and that there is little, if any, risk for any other type of cancer, when accounting for the mode-of-action in humans.

Selection of yeast strains in naturally fermented cured meat as promising starter cultures for fermented cured beef, a traditional fermented meat product of northern China

BACKGROUND

Fermented meat products are meat products with a unique flavor, color, and texture as well as an extended shelf life under natural or artificially controlled conditions. Microorganisms or enzymes are used to ferment the raw meat so that it undergoes a series of biochemical and physical changes. Common fermentation strains are lactic acid bacteria, yeasts, staphylococci, molds, and so forth. Studies on the inhibitory effect of yeast fermentation strain on N-nitrosamines in fermented meat products have not been reported. Two excellent yeast starters were identified to solve the problem of nitrosamines in fermented meat products.

RESULTS

Meyerozyma guilliermondii and Debaryomyces hansenii led to weak acid production, strong resistance to NaCl and NaNO2 , and high tolerance to low acidic conditions. The inoculated fermented beef exhibited decreased lightness, moisture content, water activity, pH, protein content, nitrite content, and N-nitrosamine content in comparison with the control group fermented bacon. M. guilliermondii had a better effect, reducing pH from 5.69 to 5.41, protein content from 254.24 to 221.92 g·kg-1 , nitrite content from 28.61 to 25.33 mg·kg-1 and N-nitrosamine by 18.97%, and giving the fermented beef the desired meat color, mouthfeel, odor, taste, and tissue quality.

CONCLUSION

In this study, two strains of yeast fermenters that can degrade N-nitrosamine precursors were identified, which to some extent solves the problem of the high risk of generating nitrosamines such as N-nitrosodiethylamine (NDEA) by processing fermented meat products with nitrites as precursors. These two strains are likely to be used as starter cultures for fermented meat products. © 2023 Society of Chemical Industry.

Prenatal exposure to nitrosatable drugs and timing of puberty in sons and daughters: A nationwide cohort study

BACKGROUND

N-nitroso compounds (NOCs) can be formed by endogenous reactions between nitrosatable drugs and nitrite. Animal studies have found that several NOCs are teratogenic, and epidemiological studies report associations between prenatal exposure to nitrosatable drugs and adverse birth outcomes. It is unknown whether prenatal exposure to nitrosatable drugs is harmful to the child's reproductive health, including pubertal development.

OBJECTIVES

We investigated whether prenatal exposure to nitrosatable drugs was associated with timing of puberty and whether nitrate, nitrite and antioxidant intake modified any association.

METHODS

The population-based Danish National Birth Cohort (DNBC) Puberty Cohort, which includes 15,819 children, was used to investigate the association between prenatal exposure to nitrosatable drugs and timing of puberty. Around gestational week 11 and gestational week 18, mothers provided information about drug use during pregnancy. The children's self-reported information on onset of pubertal milestones was collected every six months from 11 years of age and throughout puberty. To investigate potential effect modification by nitrite, nitrate and antioxidant intake, information on these factors was obtained from a food frequency questionnaire completed by the mothers in gestational week 25, and information on nitrate concentration in maternal drinking water at her residential address was obtained from monitoring data from public waterworks. Data were analysed using a multivariable regression model for interval-censored data estimating difference in months in timing of puberty between exposure groups.

RESULTS

A total of 2,715 children were prenatally exposed to nitrosatable drugs. We did not find an association between prenatal exposure to nitrosatable drugs and timing of puberty. This finding was supported by null-findings in the following sub-analyses investigating: 1. subtypes of nitrosatable drugs (secondary and tertiary amines and amides), 2. dose-dependency (duration of drug intake), 3. effect modification by maternal intake of nitrate, nitrite, and antioxidants. 4. confounding by indication.

CONCLUSIONS

Prenatal exposure to nitrosatable drugs was not associated with timing of puberty. Nitrosatable drugs are commonly used drugs in pregnancy, and further research is needed to allow firm conclusions on the potential effect of prenatal exposure to nitrosatable drugs on the child's reproductive health.

Electrochemical and Optical Sensors for Real-Time Detection of Nitrate in Water

The health and integrity of our water sources are vital for the existence of all forms of life. However, with the growth in population and anthropogenic activities, the quality of water is being impacted globally, particularly due to a widespread problem of nitrate contamination that poses numerous health risks. To address this issue, investigations into various detection methods for the development of in situ real-time monitoring devices have attracted the attention of many researchers. Among the most prominent detection methods are chromatography, colorimetry, electrochemistry, and spectroscopy. While all these methods have their pros and cons, electrochemical and optical methods have emerged as robust and efficient techniques that offer cost-effective, accurate, sensitive, and reliable measurements. This review provides an overview of techniques that are ideal for field-deployable nitrate sensing applications, with an emphasis on electrochemical and optical detection methods. It discusses the underlying principles, recent advances, and various measurement techniques. Additionally, the review explores the current developments in real-time nitrate sensors and discusses the challenges of real-time implementation.

Silver-functionalized bismuth oxide (AgBi2O3) nanoparticles for the superior electrochemical detection of glucose, NO2- and H2O2

In this study, silver-functionalized bismuth oxide (AgBi₂O₃) nanoparticles (SBO NPs) were successfully synthesized by a highly efficient hydrothermal method. The as-synthesized SBO nanoparticles were characterized using FT-IR, P-XRD, XPS, HR-SEM, and HR-TEM analytical methods. It was found that the NPs were in spherical shape and hexagonal crystal phase. The newly prepared SBO electrode was further utilized for the detection of glucose, NO₂^- and H₂O₂ by cyclic voltammetry (CV) and amperometric methods. The electrodes exhibited high sensitivity (2.153 μA mM^-1 cm^-2 for glucose, 22 μA mM^-1 cm^-2 for NO₂^- and 1.72 μA mM^-1 cm^-2 for H₂O₂), low LOD (0.87 μM for glucose, 2.8 μM for NO₂^- and 1.15 μM for H₂O₂) and quick response time (3 s for glucose, 2 s for both NO₂^- and H₂O₂ respectively). The sensor exhibited outstanding selectivity despite the presence of various interferences. The developed sensor exhibited good repeatability, reproducibility, and stability. In addition, the sensor was used to measure glucose, H₂O₂ in human serum, and NO₂^- in milk and river water samples, demonstrating its potential for use in the real sample.

Toxicokinetic and mass balance of morpholine in rats

Morpholine (MOR) has a broad spectrum of use and represents high risk of human exposure. Ingested MOR can undergo endogenous N-nitrosation in the presence of nitrosating agents forming N-nitrosomorpholine (NMOR), classified as possible human carcinogen by the International Agency for Research on Cancer.In this study, we evaluated the MOR toxicokinetics in six groups of male Sprague-Dawley rats orally exposed to 14C-radiolabelled MOR and NaNO2. The major urinary metabolite of MOR, N-nitrosohydroxyethylglycine (NHEG), was measured through HPLC as an index of endogenous N-nitrosation. Mass balance and toxicokinetic profile of MOR were determined by measuring radioactivity in blood/plasma and excreta.MOR reached maximum blood concentration 30 minutes after administration. Elimination rate was rapid (70% in 8h). Most of the radioactivity was excreted in the urine (80.9 ± 0.5%) and unchanged 14C-MOR was the main compound excreted in the urine (84% of the dose recovered). 5.8% of MOR is not absorbed and/or was not recovered.Endogenous nitrosation of MOR was demonstrated by the detection of NHEG. The maximum conversion rate found was 13.3 ± 1.2% and seems to be impacted by the MOR/NaNO2 ratio.These results help refining our knowledge of the endogenous production of NMOR, a possible human carcinogen.

Preserved vegetable consumption and its association with mortality among 440,415 people in the China Kadoorie Biobank

BACKGROUND

Fresh vegetable consumption has been associated with lower incidence of cardiovascular disease (CVD). However, whether preserved vegetable consumption is linked with CVD and mortality remains unclear. This study aimed to assess the associations of preserved vegetable consumption with all-cause and cause-specific mortality.

METHODS

A total of 440,415 participants free of major chronic diseases, aged 30-79 years, were enrolled from 10 diverse regions in China between 2004 and 2008 and were followed up for an average of 10 years. Preserved vegetable consumption was assessed using a validated food frequency questionnaire. Cause-specific hazard models with the consideration of competing risk from various deaths were performed to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of mortality.

RESULTS

During 4,415,784 person-years of follow-up, we documented 28,625 deaths. After adjustment for major risk factors, preserved vegetable consumption was marginally associated with higher CVD mortality (P = 0.041 for trend and P = 0.025 for non-linearity) but not associated with cancer mortality and total mortality. For specific causes of death, consuming preserved vegetables was associated with higher hemorrhagic stroke mortality. The multivariable-adjusted HRs (95% CIs) of hemorrhagic stroke mortality compared with non-consumers were 1.32 (1.17-1.50) for 1-3 days/week and 1.15 (1.00-1.31) for regular consumers (≥4 days/week) (P = 0.006 for trend and P < 0.001 for non-linearity). In addition, regular preserved vegetable consumption was associated with increased risk of digestive tract cancer mortality [HR (95% CI): 1.13 (1.00-1.28); P = 0.053 for trend] and esophageal cancer mortality [HR (95% CI): 1.45 (1.17-1.81); P = 0.002 for trend].

CONCLUSIONS

Frequent consumption of preserved vegetables was associated with higher risk of mortality from hemorrhagic stroke and esophageal cancer in China. Our findings suggest limiting preserved vegetable consumption might be protective for premature death from hemorrhagic stroke and digestive tract cancer.

Characteristics and health risk assessment of volatile N-nitrosamines in the plasma of adults in Guangdong Province, China

N-nitrosamines are strong carcinogens that are widely present in the environment. This study developed a method, and analyzed the concentrations of volatile N-nitrosamines (VNAs) in the plasma of adults in Guangdong Province, China. Finally, the health risks to adults in Guangdong Province, China, with dietary exposure to VNAs were assessed. Gas chromatography/mass spectrometry (GC/MS) in electron impact (EI) ionization source mode was used to quantitatively analyze VNAs, and to perform accurate mass determination. The lower limit of detection (LOD) of nine nitrosamines are ranged from 0.01 to 2.14 ng/mL. The recovery rate ranged from 83 % to 116 %, and the relative standard deviation (RSD) was < 10 %. The method developed is simple, rapid, and provides good reproducibility and high sensitivity. N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodinbutylamine (NDBA), N-nitrosopiperidine (NPIP), N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) and N-nitrosodiphenylamine (NDPhA) were detected in 92 adult plasma samples. NDMA and NMEA were detected in 56.5 % and 44.6 % of the samples, followed by NPIP (34.8 %). NDMA had the highest median concentration (43.7 ng/mL) in the total samples. There were gender-related differences found in the concentrations of NDBA and NDPhA. The exposure risk assessment results showed that the two highest daily dietary intakes of VNAs were N-nitrosodi-n-propylamine (NDPA) and NDMA, and aquatic products and pickled vegetables contributed the most total nitrosamine intake. The lifetime cancer risk of adults ranged from 2.88 × 10^-10 to 7.46 × 10^-5, and the risk associated with NDMA, NDPA, N-nitrosodiethylamine (NDEA), NMEA and NPIP are important and should attract more attention. This study aimed to explore the exposure levels of VNAs in the plasma of adults in Guangdong Province, China, and to assess the health risks of dietary intake of VNAs, which provides a basis of the effect of VNAs exposure on human health.

Plasmon-Mediated Oxidase-like Activity on Ag@ZnS Heterostructured Hollow Nanowires for Rapid Visual Detection of Nitrite

Rational design of fast and sensitive determination of nitrite (NO₂^-) from a complicated actual sample overtakes a crucial role in constructing a high-efficiency sensing platform. Herein, a visual NO₂^- sensing platform with outstanding selectivity, sensitivity, and stability based on a surface plasmon resonance (SPR)-enhanced oxidase-like activity has been proposed. Benefiting from the intrinsic photocatalytic activity and limited light penetration of ZnS, the oxidase-like activity based on ZnS decorated on Ag nanowires (Ag@ZnS) is determined. It is demonstrated that the electrons are generated efficiently on the surface of ZnS and then transferred into the hot electrons of Ag with the help of localized SPR excitation, thus greatly oxidating the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to produce dark blue oxidized TMB (oxTMB). When nitrite is added into the reaction system, the oxTMB will selectively react with NO₂^- to generate diazotized oxTMB, leading to a visual color change from dark blue to light green and subsequently to dark yellow. Owing to the specific recognition between nitrite and oxTMB, the recovery of catalytic activity induced an enhanced colorimetric test with a wider linear range for NO₂^- determination, an ultralow detection limit of 0.1 μM, excellent selectivity, and practicability for application in real samples. This plasmon-enhanced oxidase-like activity not only provides a smart approach to realize a colorimetric assay with high sensitivity and simplicity but also modulates oxidase-like activities.

Assessment of a Diverse Array of Nitrite Scavengers in Solution and Solid State: A Study of Inhibitory Effect on the Formation of Alkyl-Aryl and Dialkyl N-Nitrosamine Derivatives

The ubiquitous presence of mutagenic and potentially carcinogenic N-nitrosamine impurities in medicines has become a major issue in the pharmaceutical industry in recent years. Rigorous mitigation strategies to limit their amount in drug products are, therefore, needed. The removal of nitrite, which is a prerequisite reagent for the N-nitrosation of amines, has been acknowledged as one of the most promising strategies. We have conducted an extensive literature search to identify nineteen structurally diverse nitrite scavengers and screened their activity experimentally under pharmaceutically relevant conditions. In the screening phase, we have identified six compounds that proved to have the best nitrite scavenging properties: ascorbic acid (vitamin C), sodium ascorbate, maltol, propyl gallate, para-aminobenzoic acid (PABA), and l-cysteine. These were selected for investigation as inhibitors of the formation of N-methyl-N-nitrosoaniline (NMA) from N-methylaniline and N-nitroso-N’-phenylpiperazine (NPP) from N-phenylpiperazine in both solution and model tablets. Much faster kinetics of NMA formation compared to NPP was observed, but the former was less stable at high temperatures. Vitamin C, PABA, and l-cysteine were recognized as the most effective inhibitors under most studied conditions. The nitrite scavenging activity does not directly translate into N-nitrosation inhibitory effectiveness, indicating other reaction pathways may take place. The study presents an important contribution to identifying physiologically acceptable chemicals that could be added to drugs to prevent N-nitrosation during manufacture and storage.

MicroRNA-21 as a potential biomarker for detecting esophageal carcinoma in Asian populations: a meta-analysis

Background

MicroRNA-21 (miR-21) is significantly expressed in a variety of cancers and could be used as a tumor biomarker. However, the results are varied, and no studies on the diagnostic usefulness of miR-21 in Asian esophageal cancer (EC) patients have been published. This meta-analysis was aimed at exploring whether miR-21 can be used as a diagnostic marker and assessing its effectiveness.

Methods

The relevant literature was identified in six main databases: Ovid MEDLINE, PsycINFO, PubMed MEDLINE, Embase, Web of Science, and the Cochrane Library. Two researchers independently selected the literature based on the inclusion and exclusion criteria, extracted data, and evaluated the risk of bias. The meta-analysis was carried out using Review Manager 5.4, Meta-Disc 1.4 and STATA 15.1 software. In the end, 987 patients from 12 different studies were included. Quality evaluation of diagnostic accuracy studies 2 (QUADAS-2) was used to examine the risk of bias.

Results

The pooled sensitivity (SEN) was 0.72 (95% CI [0.69-0.75]), the pooled specificity (SPE) was 0.78 (95% CI [0.75-0.81]), the pooled positive likelihood ratio (PLR) was 2.87 (95% CI [2.28-3.59]), the pooled negative likelihood ratio (NLR) was 0.36 (95% CI [0.31-0.43]), the pooled diagnostic odds ratio (DOR) was 10.00 (95% CI [7.73-12.95]), and the area under the curve 0.82 (95% CI [0.79-0.85]). A Deeks' funnel plot shows that there was no publication bias (P = 0.99).

Conclusion

Our findings suggest miR-21 might be the potential biomarker for detecting EC in Asian populations, with a good diagnostic value.

Research progress of N-nitrosamine detection methods: a review

N-Nitrosamines (nitrosamines) are attracting increased attention because of their high toxicity and wide distribution. They have been strictly restricted by regulations in many fields. Researchers around the world have conducted substantial work on nitrosamine detection. This paper reviews the progress of research on nitrosamine detection methods with emphasis on biological-matrix samples. After introducing the category, toxicity, regulatory limit and source of nitrosamines, the paper discusses the most commonly used sample-preparation techniques and instrumental-detection techniques for nitrosamine detection, including some typical application cases.

Mechanisms and pathophysiology of Barrett oesophagus

Barrett oesophagus, in which a metaplastic columnar mucosa that can predispose individuals to cancer development lines a portion of the distal oesophagus, is the only known precursor of oesophageal adenocarcinoma, the incidence of which has increased profoundly over the past several decades. Most evidence suggests that Barrett oesophagus develops from progenitor cells at the oesophagogastric junction that proliferate and undergo epithelial-mesenchymal transition as part of a wound-healing process that replaces oesophageal squamous epithelium damaged by gastroesophageal reflux disease (GERD). GERD also seems to induce reprogramming of key transcription factors in the progenitor cells, resulting in the development of the specialized intestinal metaplasia that is characteristic of Barrett oesophagus, probably through an intermediate step of metaplasia to cardiac mucosa. Genome-wide association studies suggest that patients with GERD who develop Barrett oesophagus might have an inherited predisposition to oesophageal metaplasia and that there is a shared genetic susceptibility to Barrett oesophagus and to several of its risk factors (such as GERD, obesity and cigarette smoking). In this Review, we discuss the mechanisms, pathophysiology, genetic predisposition and cells of origin of Barrett oesophagus, and opine on the clinical implications and future research directions.

A perspective review on medicinal plant resources for their antimutagenic potentials

Mutagens present in the environment manifest toxic effects and are considered as serious threat for human health and healthcare. Recent reports reveal that medicinal plant resources are being explored for identifying potent antimutagenic as well as cancer preventing agents. There is mounting evidence that cancer and other mutation-related diseases can be prevented with the use of medicinal pant resources including crude extracts, active fractions, phytochemicals, and pure phytomolecules. These medicinal plant resources possessing antimutagenic potentials have been shown to target molecular mechanisms underlying the mutagenic impacts. Technological advents and high-throughput screening/activity methods have revolutionized this field, though several potent plants and their active principles have been reported as effective antimutagens. The translational success rate needs to be improved, but the trends are encouraging. In this review, we present the current understandings and updates on various mutagens in the environment, toxicities related/attributed to them, the resultant mutations (and cancer), and how medicinal plants come to the rescue. A perspective review has been presented on whether and how medicinal plant resources can be an effective approach for addressing mutagens in the environment. An account of medicinal plant resources used as antimutagenic agents has been given along with the underlying mechanism of action and their therapeutic potential in various models of cancer. Recent success stories, current challenges, and future prospects are discussed.

Screening and surveillance for gastric cancer: Does family history play an important role in shaping our strategy?

Family history is an important risk factor of gastric cancer. No guidelines have been developed that target gastric cancer with a family history; only hereditary familial gastric cancer is targeted. We review the available evidence regarding the familial aggregation mechanisms of gastric cancer and a strategy of screening and surveillance for gastric cancer in individuals with a positive family history of the disease. As there is a synergic effect of Helicobacter pylori infection and family history on the increased risk of gastric cancer, Helicobacter pylori eradication should be considered in all infected individuals with a family history of gastric cancer. Currently, there is weak evidence indicating that suitable timing to initiate eradication therapy is at the age of 20, when precancerous lesions, including significant gastric atrophy and intestinal metaplasia, have not been established. Reasonable timing to initiate screening for gastric cancer in individuals with a family history of gastric cancer is 10 years prior to the age of onset of gastric cancer in affected relatives. A 2-year surveillance interval, instead of the 3-year interval recommended in the present guidelines, may be better to detect early gastric cancer in those individuals who have already developed precancerous gastric lesions.

Genotoxicity evaluation of nitrosamine impurities using human TK6 cells transduced with cytochrome P450s

Many nitrosamines are recognized as mutagens and potent rodent carcinogens. Over the past few years, nitrosamine impurities have been detected in various drugs leading to drug recalls. Although nitrosamines are included in a 'cohort of concern' because of their potential human health risks, most of this concern is based on rodent cancer and bacterial mutagenicity data, and there are little data on their genotoxicity in human-based systems. In this study, we employed human lymphoblastoid TK6 cells transduced with human cytochrome P450 (CYP) 2A6 to evaluate the genotoxicity of six nitrosamines that have been identified as impurities in drug products: N-nitrosodiethylamine (NDEA), N-nitrosoethylisopropylamine (NEIPA), N-nitroso-N-methyl-4-aminobutanoic acid (NMBA), N-nitrosomethylphenylamine (NMPA), N-nitrosodiisopropylamine (NDIPA), and N-nitrosodibutylamine (NDBA). Using flow cytometry-based assays, we found that 24-h treatment with NDEA, NEIPA, NMBA, and NMPA caused concentration-dependent increases in the phosphorylation of histone H2A.X (γH2A.X) in CYP2A6-expressing TK6 cells. Metabolism of these four nitrosamines by CYP2A6 also caused significant increases in micronucleus frequency as well as G2/M phase cell-cycle arrest. In addition, nuclear P53 activation was found in CYP2A6-expressing TK6 cells exposed to NDEA, NEIPA, and NMPA. Overall, the genotoxic potency of the six nitrosamine impurities in our test system was NMPA > NDEA ≈ NEIPA > NMBA > NDBA ≈ NDIPA. This study provides new information on the genotoxic potential of nitrosamines in human cells, complementing test results generated from traditional assays and partially addressing the issue of the relevance of nitrosamine genotoxicity for humans. The metabolically competent human cell system reported here may be a useful model for risk assessment of nitrosamine impurities found in drugs.

Association Between Ultra-Processed Food Intake and All-Cause Mortality: A Systematic Review and Meta-Analysis

Consumption of ultra-processed foods (UPF) has increased worldwide during the last decades because they are hyperpalatable, cheap, and ready-to-consume products. However, uncertainty exists about their impact on health. We conducted a systematic review and meta-analysis evaluating the association of UPF consumption with all-cause mortality risk. Five bibliographic databases were searched for relevant studies. Random effects models were used to calculate pooled relative risks (RRs) and 95% confidence intervals (CIs). Of 6,951 unique citations, 40 unique prospective cohort studies comprising 5,750,133 individuals were included; publication dates ranged from 1984 to 2021. Compared with low consumption, highest consumption of UPF (RR = 1.29, 95% CI: 1.17, 1.42), sugar-sweetened beverages (RR = 1.11, 95% CI, 1.04, 1.18), artificially sweetened beverages (RR = 1.14, 95% CI, 1.05, 1.22), and processed meat/red meat (RR = 1.15, 95% CI, 1.10, 1.21) were significantly associated with increased risk of mortality. However, breakfast cereals were associated with a lower mortality risk (RR = 0.85, 95% CI, 0.79, 0.92). This meta-analysis suggests that high consumption of UPF, sugar-sweetened beverages, artificially sweetened beverages, processed meat, and processed red meat might increase all-cause mortality, while breakfast cereals might decrease it. Future studies are needed to address lack of standardized methods in UPF categorization.

A Genetic Toxicology Study of the Rapid Detection of Nitrosamine Compounds by the rpsL Gene Mutation Assay

In a rpsL gene mutation experiment, the mutagenicity of the nitrosamine compounds N-diethylnitrosamine (NDEA) and N-dipropylnitrosamine (NDPA) was investigated at the cellular level, as well as with PCR (polymerase chain reaction) and RCA (rolling-circle amplification) amplification systems. The experiments were set up with 10 ppm, 100 ppm, and 1000 ppm concentration gradients of NDEA and NDPA, and ethidium bromide (EB) was used as a positive control group. The results demonstrated that the mutagenic frequency of NDEA and NDPA was significantly higher than the spontaneous mutation frequency of the rpsL gene under the same conditions, but lower than the mutagenic rate of EB in the positive control, and there was a dose-effect relationship, indicating that NDEA and NDPA could induce rpsL gene mutation. The rpsL mutation system has a low spontaneous mutation background and high sensitivity, thus the system is expected to become an effective tool for the rapid detection of carcinogens in the field of food.

Plant-Based Diet: Is It as Good as an Animal-Based Diet When It Comes to Protein?

PURPOSE OF REVIEW

Protein is a macronutrient that is responsible for multiple functions in the human body and is made up of twenty amino acids. Nine amino acids are not synthesized in the human body and require dietary ingestion to prevent deficiency. These essential amino acids are easily obtained through animal-based proteins but can be in limited quantities through plant-based protein sources. With the obesity epidemic rising, great attention has turned to plant-based protein diets and their health and environmental implications. The differences in plant and animal protein sources have been explored for their effects on general health, sarcopenia, and muscle performance. This review discusses the benefits and drawbacks of a plant-based diet, as well as some of the latest literature on muscle protein synthesis between animal- and plant-based dietary intakes of protein.

RECENT FINDINGS

High meat consumption is associated with increased saturated fat intake and lower dietary fiber intake. As a result, meat consumption is correlated with obesity, heart disease, metabolic syndrome, and gastrointestinal cancers. However, animal-based diets contain higher amounts of leucine and other essential amino acids which are associated with increased anabolic potential and muscle protein synthesis. Yet, multiple studies show conflicting results on the true benefits of animal-based diets, suggesting total protein intake may be the best predictor for preserving lean muscle mass and increasing muscle performance. While many studies support animal protein sources superior to plant-based diets on intracellular anabolic signaling, other studies show conflicting results regarding the true benefit of animal-based protein diets on overall performance and effect on sarcopenia. The health benefits seem to favor plant-based protein sources; however, further research is needed to examine the effects of protein from plant- and animal-based diets on muscle mass and protein synthesis.

Ranitidine Use and Gastric Cancer Among Persons with Helicobacter pylori

BACKGROUND

The Food and Drug Administration requested withdrawal of ranitidine formulations, due to a potentially carcinogenic contaminant, N-nitrosodimethylamine.

AIMS

We evaluate whether ranitidine use is associated with gastric cancer.

METHODS

This is a retrospective multicenter, nationwide cohort study within the Veterans Health Administration, among patients with Helicobacter pylori (HP) prescribed long-term acid suppression with either: (1) ranitidine, (2) other histamine type 2 receptor blocker (H2RB), or (3) proton pump inhibitor (PPI)) between May 1, 1998, and December 31, 2018. Covariates included race, ethnicity, smoking, age, HP treatment, HP eradication. Primary outcome was non-proximal gastric adenocarcinomas, using multivariable Cox proportional hazards analysis.

RESULTS

We identified 279,505 patients with HP prescribed long-term acid suppression (median 53.4 years; 92.9% male). Compared to ranitidine, non-ranitidine H2RB users were more likely to develop cancer (HR 1.83, 95%CI 1.36-2.48); PPI users had no significant difference in future cancer risk (HR 0.92, 95% CI 0.82-1.04), p < 0.001. Demographics associated with future cancer included increasing age (HR 1.18, 95% CI 1.15-1.20, p < 0.001), Hispanic/Latino ethnicity (HR 1.46, 95% CI 1.21-1.75, p < 0.001), Black race (HR 1.89, 95% CI 1.68-2.14) or Asian race (HR 2.03, 95% CI 1.17-3.52), p < 0.001, and gender (female gender HR 0.64, 95% CI 0.48-0.85, p = 0.02). Smoking was associated with future cancer (HR 1.38, 95% CI 1.23-1.54, p < 0.001). Secondary analysis demonstrated decreased cancer risk in those with confirmed HP eradication (HR 0.24, 95% CI 0.14-0.40). No association between ranitidine and increased gastric cancer was found.

CONCLUSION

There is no demonstrable association between ranitidine use and future gastric cancer among individuals with HP on long-term acid suppression.

Metabolites profiling reveals gut microbiome-mediated biotransformation of green tea polyphenols in the presence of N-nitrosamine as pro-oxidant

The gut microbiome contributes to host physiology and nutrition metabolism. The interaction between nutrition components and the gut microbiota results in thousands of metabolites that can contribute to various health and disease outcomes. In parallel, the interactions between foods and their toxicants have captured increasing interest due to their impact on human health.  Taken together, investigating dietary interactions with endogenous and exogenous factors and detecting interaction biomarkers in a specific and sensitive manner is an important task. The present study sought  to identify for the first time the metabolites produced during the interaction of diet-derived toxicants e.g., N-nitrosamines with green tea polyphenols, using liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). In addition, the metabolic products resulting from the incubation of green tea with a complex gut microbiome in the presence of N-nitrosamine were assessed in the same manner. The quinone products of (epi)catechin, quercetin, and kaempferol were identified when green tea was incubated with N-nitrosamine only; whereas, incubation of green tea with N-nitrosamine and a complex gut microbiome prevented the formation of these metabolites. This study provides a new perspective on the role of gut microbiome in protecting against potential negative interactions between food-derived toxicants and dietary polyphenols.

Nitrate in Groundwater Resources of Hormozgan Province, Southern Iran: Concentration Estimation, Distribution and Probabilistic Health Risk Assessment Using Monte Carlo Simulation

High nitrate concentration in drinking water has the potential to cause a series of harmful effects on human health. This study aims to evaluate the health risk of nitrate in groundwater resources of Hormozgan province in four age groups, including infants, children, teenagers, and adults, based on the US EPA methodology and Monte Carlo technique to assess uncertainty and sensitivity analysis. A Geographic Information System (GIS) was used to investigate the spatial distribution of nitrate levels in the study area. The nitrate concentration ranged from 0.3 to 30 mg/L, with an average of 7.37 ± 5.61 mg/L. There was no significant difference between the average concentration of nitrate in all study areas (p > 0.05). The hazard quotient (HQ) was less than 1 for all age groups and counties, indicating a low-risk level. The HQ95 for infants and children in the Monte Carlo simulation was 1.34 and 1.22, respectively. The sensitivity analysis findings showed that the parameter with the most significant influence on the risk of toxicity in all age groups was the nitrate content. Therefore, implementing a water resources management program in the study area can reduce nitrate concentration and enhance water quality.

Association between Dietary Nitrate, Nitrite Intake, and Site-Specific Cancer Risk: A Systematic Review and Meta-Analysis

BACKGROUND

People consume nitrates, nitrites, nitrosamines, and NOCs compounds primarily through processed food. Many studies have yielded inconclusive results regarding the association between cancer and dietary intakes of nitrates and nitrites. This study aimed to quantify these associations across the reported literature thus far.

METHODS

We performed a systematic review following PRISMA and MOOSE guidelines. A literature search was performed using Web of Science, Embase, PubMed, the Cochrane library, and google scholar up to January 2020. STATA version 12.0 was used to conduct meta-regression and a two-stage meta-analysis.

RESULTS

A total of 41 articles with 13 different cancer sites were used for analysis. Of these 13 cancer types/sites, meta-regression analysis showed that bladder and stomach cancer risk was greater, and that pancreatic cancer risk was lower with increasing nitrite intakes. Kidney and bladder cancer risk were both lower with increasing nitrate intakes. When comparing highest to lowest (reference) categories of intake, meta-analysis of studies showed that high nitrate intake was associated with an increased risk of thyroid cancer (OR = 1.40, 95% CI: 1.02, 1.77). When pooling all intake categories and comparing against the lowest (reference) category, higher nitrite intake was associated with an increased risk of glioma (OR = 1.12, 95% CI: 1.03, 1.22). No other associations between cancer risk and dietary intakes of nitrates or nitrites were observed.

CONCLUSION

This study showed varied associations between site-specific cancer risks and dietary intakes of nitrate and nitrite. Glioma, bladder, and stomach cancer risks were higher and pancreatic cancer risk was lower with higher nitrite intakes, and thyroid cancer risk was higher and kidney cancer risk lower with higher nitrate intakes. These data suggest type- and site-specific effects of cancer risk, including protective effects, from dietary intakes of nitrate and nitrite.

Association Between Chronic Hepatitis C Virus Infection and Esophageal Cancer: A Systematic Review and Meta-analysis

BACKGROUND

Chronic hepatitis C virus (HCV) infection is associated with increased risk of hepatobiliary tract cancer. However, whether chronic HCV infection is also associated with elevated risk of other types of cancer is still unknown. This systematic review and meta-analysis was conducted in order to investigate whether chronic HCV infection is positively associated with esophageal cancer.

METHODS

A systematic review was conducted using Embase and MEDLINE databases from inception to November 2019, with a search strategy that comprised the terms for "hepatitis C virus" and "cancer." Eligible studies were cohort studies consisting of patients with chronic HCV infection and comparators without HCV infection, and followed them for incident esophageal cancer. Hazard risk ratio, incidence rate ratio, relative risk or standardized incidence ratio of this association were extracted from each eligible study along with their 95% confidence intervals and were combined to calculate the pooled effect estimate using the random effect, generic inverse variance method.

RESULTS

A total of 20,459 articles were identified using this search strategy. After 2 rounds of independent review, 7 studies satisfied the inclusion criteria and were included in the meta-analysis. Chronic HCV infection was significantly associated with a higher incidence of esophageal cancer with the pooled relative risk of 1.61 (95% confidence interval: 1.19-2.17; I2=39%). The funnel plot was relatively symmetric which was not suggestive of publication bias.

CONCLUSION

This systematic review and meta-analysis demonstrated that there is a modest association between chronic HCV and incident esophageal cancer. However, more studies are needed to investigate the causality of this association.

A concise review towards defining the exposome of oesophageal cancer in sub-Saharan Africa

CONTEXT

Oesophageal cancer (EC) is among the common causes of illness and death among all cancers worldwide. Advanced EC has a poor prognosis, with worse outcomes observed in low-income settings. Oesophageal squamous cell carcinoma (ESCC) is the most common EC histology reported globally, with the highest ESCC incidence rates in the 'Asian Belt' and the African EC corridor. While the aetiology of ESCC is well-documented in the 'Asian belt', data for the African EC corridor and the entirety of sub-Saharan Africa (SSA) are fewer.

OBJECTIVE

To help address gaps in ESCC aetiology in SSA, we critically evaluated evidence of lifestyle, environmental, and epigenetic factors associated with ESCC risk and discussed prospects of defining ESCC exposome.

DATA INCLUSION

Unlimited English and non-English articles search were made on PubMed Central and Web of Science databases from January 1970 to August 2021. In total, we retrieved 999 articles and considered meta-analyses, case-control, and cohort studies. The quality of individual studies was assessed using the Newcastle-Ottawa scale.

DATA EXTRACTION

Details extracted include the year of publication, country of origin, sample size, comparators, outcomes, study subjects, and designs.

DATA ANALYSIS

Together, we assessed 13 case-control studies and two meta-analyses for the effect of lifestyle or environmental exposures on ESCC risk. Again, we evaluated seven case-control studies and one meta-analysis regarding the role of epigenetics in ESCC tumorigenesis.

RESULTS

In general, evidence of ESCC aetiology points to essential contributions of alcohol, tobacco, hot beverages, biomass fuel, and poor oral health/hygiene, although more precise risk characterisation remains necessary.

CONCLUSION

We conclude that ESCC in SSA is a multifactorial disease initiated by several external exposures that may induce aberrant epigenetic changes. The expanding aetiological research in this domain will be enhanced by evidence synthesis from classical and molecular epidemiological studies spanning the external and internal exposome.

Contributing factors common to COVID‑19 and gastrointestinal cancer

The devastating complications of coronavirus disease 2019 (COVID-19) result from the dysfunctional immune response of an individual following the initial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Multiple toxic stressors and behaviors contribute to underlying immune system dysfunction. SARS-CoV-2 exploits the dysfunctional immune system to trigger a chain of events, ultimately leading to COVID-19. The authors have previously identified a number of contributing factors (CFs) common to myriad chronic diseases. Based on these observations, it was hypothesized that there may be a significant overlap between CFs associated with COVID-19 and gastrointestinal cancer (GIC). Thus, in the present study, a streamlined dot-product approach was used initially to identify potential CFs that affect COVID-19 and GIC directly (i.e., the simultaneous occurrence of CFs and disease in the same article). The nascent character of the COVID-19 core literature (~1-year-old) did not allow sufficient time for the direct effects of numerous CFs on COVID-19 to emerge from laboratory experiments and epidemiological studies. Therefore, a literature-related discovery approach was used to augment the COVID-19 core literature-based ‘direct impact’ CFs with discovery-based ‘indirect impact’ CFs [CFs were identified in the non-COVID-19 biomedical literature that had the same biomarker impact pattern (e.g., hyperinflammation, hypercoagulation, hypoxia, etc.) as was shown in the COVID-19 literature]. Approximately 2,250 candidate direct impact CFs in common between GIC and COVID-19 were identified, albeit some being variants of the same concept. As commonality proof of concept, 75 potential CFs that appeared promising were selected, and 63 overlapping COVID-19/GIC potential/candidate CFs were validated with biological plausibility. In total, 42 of the 63 were overlapping direct impact COVID-19/GIC CFs, and the remaining 21 were candidate GIC CFs that overlapped with indirect impact COVID-19 CFs. On the whole, the present study demonstrates that COVID-19 and GIC share a number of common risk/CFs, including behaviors and toxic exposures, that impair immune function. A key component of immune system health is the removal of those factors that contribute to immune system dysfunction in the first place. This requires a paradigm shift from traditional Western medicine, which often focuses on treatment, rather than prevention.

Overview of Helicobacter pylori Infection: Clinical Features, Treatment, and Nutritional Aspects

Helicobacter pylori (H. pylori) is a 0.5-1 µm wide, 2-4 µm long, short helical, S-shaped Gram-negative microorganism. It is mostly found in the pyloric region of the stomach and causes chronic gastric infection. It is estimated that these bacteria infect more than half of the world's population. The mode of transmission and infection of H. pylori is still not known exactly, but the faecal-oral and oral-oral routes via water or food consumption are thought to be a very common cause. In the last three decades, research interest has increased regarding the pathogenicity, microbial activity, genetic predisposition, and clinical treatments to understand the severity of gastric atrophy and gastric cancer caused by H. pylori. Studies have suggested a relationship between H. pylori infection and malabsorption of essential micronutrients, and noted that H. pylori infection may affect the prevalence of malnutrition in some risk groups. On the other hand, dietary factors may play a considerably important role in H. pylori infection, and it has been reported that an adequate and balanced diet, especially high fruit and vegetable consumption and low processed salty food consumption, has a protective effect against the outcomes of H. pylori infection. The present review provides an overview of all aspects of H. pylori infection, such as clinical features, treatment, and nutrition.

Nitrate increases cisplatin chemosensitivity of oral squamous cell carcinoma via REDD1/AKT signaling pathway

Although cisplatin is one of the chemotherapeutics most frequently used in oral squamous cell carcinoma (OSCC) treatment, it exerts multiple side effects and poor chemosensitivity. Nitrate reportedly demonstrates several beneficial biological functions, and synthesized nitrates enhance the therapeutic efficacy of chemotherapy. However, the role of inorganic nitrate in cisplatin chemotherapy remains unclear. We therefore investigated the effect of inorganic nitrate exerted on cisplatin sensitivity in OSCC. We found that nitrate did not affect OSCC cell growth and apoptosis in OSCC cells and OSCC xenograft tumor animal studies. Cisplatin induced REDD1 expression and AKT activation in OSCC. However, nitrate could increase cisplatin chemosensitivity, reduce its REDD1 expression, and attenuate AKT signaling activation in OSCC cells. Dysregulation of high levels of REDD1, which could enhance AKT activation, was positively associated with poor prognosis in OSCC patients. Thus, reduced REDD1 expression and retarded AKT activation induced by inorganic nitrate might be a new potential approach to the sensitization of oral cancer to cisplatin treatment in the future.

Helicobacter pylori in Human Stomach: The Inconsistencies in Clinical Outcomes and the Probable Causes

Pathogenic potentials of the gastric pathogen, Helicobacter pylori, have been proposed, evaluated, and confirmed by many laboratories for nearly 4 decades since its serendipitous discovery in 1983 by Barry James Marshall and John Robin Warren. Helicobacter pylori is the first bacterium to be categorized as a definite carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO). Half of the world’s population carries H. pylori, which may be responsible for severe gastric diseases like peptic ulcer and gastric cancer. These two gastric diseases take more than a million lives every year. However, the role of H. pylori as sole pathogen in gastric diseases is heavily debated and remained controversial. It is still not convincingly understood, why most (80–90%) H. pylori infected individuals remain asymptomatic, while some (10–20%) develop such severe gastric diseases. Moreover, several reports indicated that colonization of H. pylori has positive and negative associations with several other gastrointestinal (GI) and non-GI diseases. In this review, we have discussed the state of the art knowledge on “H. pylori factors” and several “other factors,” which have been claimed to have links with severe gastric and duodenal diseases. We conclude that H. pylori infection alone does not satisfy the “necessary and sufficient” condition for developing aggressive clinical outcomes. Rather, the cumulative effect of a number of factors like the virulence proteins of H. pylori, local geography and climate, genetic background and immunity of the host, gastric and intestinal microbiota, and dietary habit and history of medicine usage together determine whether the H. pylori infected person will remain asymptomatic or will develop one of the severe gastric diseases.

Helicobacter pylori-Induced Inflammation: Possible Factors Modulating the Risk of Gastric Cancer

Chronic inflammation and long-term tissue injury are related to many malignancies, including gastric cancer (GC). Helicobacter pylori (H. pylori), classified as a class I carcinogen, induces chronic superficial gastritis followed by gastric carcinogenesis. Despite a high prevalence of H. pylori infection, only about 1–3% of people infected with this bacterium develop GC worldwide. Furthermore, the development of chronic gastritis in some, but not all, H. pylori-infected subjects remains unexplained. These conflicting findings indicate that clinical outcomes of aggressive inflammation (atrophic gastritis) to gastric carcinogenesis are influenced by several other factors (in addition to H. pylori infection), such as gut microbiota, co-existence of intestinal helminths, dietary habits, and host genetic factors. This review has five goals: (1) to assess our current understanding of the process of H. pylori-triggered inflammation and gastric precursor lesions; (2) to present a hypothesis on risk modulation by the gut microbiota and infestation with intestinal helminths; (3) to identify the dietary behavior of the people at risk of GC; (4) to check the inflammation-related genetic polymorphisms and role of exosomes together with other factors as initiators of precancerous lesions and gastric carcinoma; and (5) finally, to conclude and suggest a new direction for future research.

DNA damage in cancer development: special implications in viral oncogenesis

DNA lesions arise from a combination of physiological/metabolic sources and exogenous environmental influences. When left unrepaired, these alterations accumulate in the cells and can give rise to mutations that change the function of important proteins (i.e. tumor suppressors, oncoproteins), or cause chromosomal rearrangements (i.e. gene fusions) that also result in the deregulation of key cellular molecules. Progressive acquisition of such genetic changes promotes uncontrolled cell proliferation and evasion of cell death, and hence plays a key role in carcinogenesis. Another less-studied consequence of DNA damage accumulating in the host genome is the integration of oncogenic DNA viruses such as Human papillomavirus, Merkel cell polyomavirus, and Hepatitis B virus. This critical step of viral-induced carcinogenesis is thought to be particularly facilitated by DNA breaks in both viral and host genomes. Therefore, the impact of DNA damage on carcinogenesis is magnified in the case of such oncoviruses via the additional effect of increasing integration frequency. In this review, we briefly present the various endogenous and exogenous factors that cause different types of DNA damage. Next, we discuss the contribution of these lesions in cancer development. Finally, we examine the amplified effect of DNA damage in viral-induced oncogenesis and summarize the limited data existing in the literature related to DNA damage-induced viral integration. To conclude, additional research is needed to assess the DNA damage pathways involved in the transition from viral infection to cancer. Discovering that a certain DNA damaging agent increases the likelihood of viral integration will enable the development of prophylactic and therapeutic strategies designed specifically to prevent such integration, with an ultimate goal of reducing or eliminating these viral-induced malignancies.

A solvent-free headspace GC/MS method for sensitive screening of N-nitrosodimethylamine in drug products

A solvent-free headspace gas chromatography-mass spectrometry (SF-HS-GC/MS) method was developed and validated for screening N-nitrosodimethylamine (NDMA) in various active pharmaceutical ingredients (APIs) and drug products. Experimental parameters such as incubation temperature, incubation time, and sample volume in solvent-free headspace conditions were optimized. The developed SF-HS-GC/MS method was validated in terms of linearity, limit of quantification (LOQ), precision, and accuracy. The results indicated excellent linearity from 5 to 500 ng g^-1 with correlation coefficients higher than 0.9999. The LOQ of this method was 5 ng g^-1 and matrix effects ranged from 0.97 to 1.11. The accuracy ranged from 92.77 to 106.54% and the precision RSDs were below 5.94%. No significant matrix effect was observed for any of the drug products. Also, artefactual NDMA formation in ranitidine, nizatidine, and metformin was investigated under HS conditions. Adjusted (mild) SF-HS conditions were suggested for precise quantification of NDMA in positive drug products by GC/MS. The present SF-HS-GC/MS method is a promising tool for the screening and determination of toxic NDMA in APIs and drug products.

Nitrosamine removal: Pilot-scale comparison of advanced oxidation, nanofiltration, and biological activated carbon processes

Removal of nitrosamines from water intended for consumption is an important topic due to the carcinogenic risks they pose to human health. In this study, we measure and compare nitrosamine removal by four individuals and three combinations of water treatments applied in situ as a pilot study and in the laboratory. Of the two advanced oxidation processes tested, UV irradiation at a wavelength of 254 nm was more effective in nitrosamine removal than ozonation; however, the efficacy of UV photolysis required a high dose (>635 mJ/cm²) for sufficient (>90%) removal of the contaminants. The biological activated carbon (BAC) process was also effective at removing nitrosamines, most of which were adsorbed onto the carbon. A small fraction (<10%) of nitrosamines were removed through biodegradation. Nanofiltration membranes were limited in removing nitrosamines, particularly N-nitrosodimethylamine, which is hydrophilic. Employing either UV or BAC treatments can warrant a high degree of elimination of nitrosamines; however, desorption of nitrosamines from BAC can occur due to variations in the quality of source water and the types of carbon filters used. Combined treatments using both UV and BAC processes offer promising alternative strategies for removing nitrosamines when treating water for human consumption.

Quality Assessment of Wild and Cultivated Green Tea from Different Regions of China

Natural products have always enjoyed great popularity among consumers. Wild tea is an interesting alternative to tea from intensive plantations. The term "wild tea" is applied to many different varieties of tea, the most desirable and valued of which are native or indigenous tea plants. Special pro-health properties of wild tea are attributed to the natural conditions in which it grows. However, there are no complex studies that describe quality and health indicators of wild tea. The aim of this research was to evaluate the quality of wild and cultivated green tea from different regions of China: Wuzhishan, Baisha, Kunlushan, and Pu'Er. The assessment was carried out by verifying the concentration of selected chemical components in tea and relating it to the health risks they may pose, as well as to the nutritional requirements of adults. Wild tea was characterized by higher micronutrient concentration. The analyzed teas can constitute a valuable source of Mn in the diet. A higher concentration of nitrates and oxalates in cultivated tea can be associated with fertilizer use. The analyzed cultivated tea was a better source of antioxidants with a higher concentration of caffeine. There were no indications of health risks for wild or cultivated teas.

Role of microbial dysbiosis in the pathogenesis of esophageal mucosal disease: A paradigm shift from acid to bacteria?

Genomic sequencing, bioinformatics, and initial speciation (e.g., relative abundance) of the commensal microbiome have revolutionized the way we think about the "human" body in health and disease. The interactions between the gut bacteria and the immune system of the host play a key role in the pathogenesis of gastrointestinal diseases, including those impacting the esophagus. Although relatively stable, there are a number of factors that may disrupt the delicate balance between the luminal esophageal microbiome (EM) and the host. These changes are thought to be a product of age, diet, antibiotic and other medication use, oral hygiene, smoking, and/or expression of antibiotic products (bacteriocins) by other flora. These effects may lead to persistent dysbiosis which in turn increases the risk of local inflammation, systemic inflammation, and ultimately disease progression. Research has suggested that the etiology of gastroesophageal reflux disease-related esophagitis includes a cytokine-mediated inflammatory component and is, therefore, not merely the result of esophageal mucosal exposure to corrosives (i.e., acid). Emerging evidence also suggests that the EM plays a major role in the pathogenesis of disease by inciting an immunogenic response which ultimately propagates the inflammatory cascade. Here, we discuss the potential role for manipulating the EM as a therapeutic option for treating the root cause of various esophageal disease rather than just providing symptomatic relief (i.e., acid suppression).

Role of the Gastric Microbiome in Gastric Cancer: From Carcinogenesis to Treatment

The development of sequencing technology has expanded our knowledge of the human gastric microbiome, which is now known to play a critical role in the maintenance of homeostasis, while alterations in microbial community composition can promote the development of gastric diseases. Recently, carcinogenic effects of gastric microbiome have received increased attention. Gastric cancer (GC) is one of the most common malignancies worldwide with a high mortality rate. Helicobacter pylori is a well-recognized risk factor for GC. More than half of the global population is infected with H. pylori, which can modulate the acidity of the stomach to alter the gastric microbiome profile, leading to H. pylori-associated diseases. Moreover, there is increasing evidence that bacteria other than H. pylori and their metabolites also contribute to gastric carcinogenesis. Therefore, clarifying the contribution of the gastric microbiome to the development and progression of GC can lead to improvements in prevention, diagnosis, and treatment. In this review, we discuss the current state of knowledge regarding changes in the microbial composition of the stomach caused by H. pylori infection, the carcinogenic effects of H. pylori and non-H. pylori bacteria in GC, as well as the potential therapeutic role of gastric microbiome in H. pylori infection and GC.

Mechanistic insights into the treatment of iron-deficiency anemia and arthritis in humans with dietary molybdenum

In the last few decades, there has been a resurgence in interest in the use of dietary supplements to treat diseases in humans and molybdenum has the potential to be used therapeutically. In humans, dietary molybdenum has been shown to treat iron-deficiency anemia and it may treat joint pain in arthritis. It has been proposed that the anti-anemic and tentative anti-arthritic properties of molybdenum are because it is increasing the activity of one or more mammalian molybdoenzymes. Molybdenum forms part of the active site of these enzymes. Despite this, it is unlikely that a molybdenum deficiency can develop in humans that are on an oral diet and not exposed to unsafe levels of a molybdenum antagonist. Therefore, the underlying mechanism by which dietary molybdenum treats or may treat these diseases is currently not known. This minireview examines three possible underlying mechanisms. It investigates the possibility that molybdenum: increases the quantity of active mammalian molybdoenzymes, restores or partially restores activity to malfunctioning mammalian molybdoenzymes, or blocks nuclear receptors, in cells. The examination of these mechanisms has provided an impression of the mechanism by which molybdenum treats iron-deficiency anemia and may treat arthritis; and hypothesize uses of molybdenum for other human diseases.