A M-PEEK rod system to stabilize spinal motion after graded facetectomy: a finite element study.

BACKGROUND: Resecting the facet joint to relieve nerve pain can lead to spinal instability, deformity, and abnormal pressure on the anterior of the intravertebral disc. To mitigate these issues, surgeons often limit the amount of bone removed during facetectomy or stabilize the spine by fusion to maintain lumbar stability. This study aimed to assess how a M-PEEK rod system influenced the stability of the lumbar spine during graded facetectomy. METHODS: Facetectomy was performed on a validated L1-L5 finite element model which was then simulated both with and without the M-PEEK rod system. RESULTS: In extension, models implanted with M-PEEK in the interspinous space of L3/L4 experienced a 35.2% decrease in range of motion (ROM) at L3/L4, while others saw an 8.4-24.8% increase. For axial rotation, the ROM at L3/L4 increased by 2.2-5.4% in models with the M-Rod, and by 4.9-12.9% in models without the implant. In lateral flexion, the ROM at L3/L4 increased by 8.4-14.3% in models without a PEEK M-Rod (facetectomy only), with adjacent segments experiencing a 6.5% decrease in ROM in the implanted models. Overall, the difference in ROM between the intact and implanted models was minimal. CONCLUSIONS: Facetectomy involving the removal of 50% or more of the facet joint significantly increases range of motion and maximum intradiscal pressure, potentially accelerating disc degeneration, as shown in our finite element study. Stabilizing the segment with an M-PEEK rod may limit excessive motion, providing stability and maintaining intradiscal pressure closer to that of an intact model.

Urinary paraben exposure increases the risk of a low estimated glomerular filtration rate in Taiwanese general population.

BACKGROUND: The inconsistent relationship between chemical exposure and estimated glomerular filtration rate (eGFR) has been examined in only a few studies. We investigated the association between paraben exposure and indicators of renal function in a total of 361 individuals recruiting from a representative study. METHOD: The levels of urinary parabens, including methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP), were measured using UPLC-MS/MS. The association between paraben exposure and indices of renal function was assessed using multiple logistic regression and Bayesian Kernel Machine Regression (BKMR). RESULTS: The median levels of urinary parabens in the adult group were significantly higher than those in the minor group, that is, 397 vs. 148 ng/mL for MeP, 38.8 vs. 13.6 ng/mL for EtP, 117 vs. 57.7 ng/mL for PrP, and 6.61 vs. 2.79 ng/mL for BuP (all P < 0.001). In the adult group, multivariate regression models confirmed a positive association between the albumin-to-creatinine ratio and urinary MeP (ß = 0.580) and a positive association of BUN (ß = 0.061) and a negative association of eGFR (ß = -0.051) with urinary EtP (all P < 0.001). In the adult group, compared with the lowest tertile group, the adjusted odds ratio in the third tertile (T3) of urinary EtP levels indicated a 3.08 times increased risk of eGFR abnormalities, followed by the second tertile (T2) with a 2.63 times increased risk. The generalized additive model (GAM) and BKMR models showed a non-linear correlation between urinary EtP levels and early CKD, as well as reduced eGFR. We observed a significant positive cumulative effect of urinary paraben on eGFR, and a significant positive single exposure effect of urinary EtP with eGFR abnormality. CONCLUSION: We found a significant association between exposure to EtP and an increased risk of high BUN levels and decreased eGFR.

Determination of 16 ultraviolet-absorbing compounds in marine invertebrates by using LC-USI-MS/MS coupled with QuEChERS.

In this study, we examined multiple endocrine-disrupting ultraviolet-absorbing compounds (UVACs) in marine invertebrates used in personal care products and packaging. Modified QuEChERS and liquid chromatography UniSpray ionization tandem mass spectrometry were used to identify 16 UVACs in marine invertebrates. Matrix-matched calibration curves revealed high linearity (r ≥ 0.9929), with limits of detection and quantification of 0.006-1.000 and 0.020-3.000 ng/g w.w., respectively. In oysters, intraday and interday analyses revealed acceptable accuracy (93%-120%) and precision (≤18%), except for benzophenone (BP) and ethylhexyl 4-(dimethylamino) benzoate. Analysis of 100 marine invertebrate samples revealed detection frequencies of 100%, 98%, 89%, 64%, and 100% for BP, 4-hydroxybenzophenone, 4-methylbenzophenone, 4-methylbenzylidene camphor, and benzophenone-3 (BP-3), respectively. BP and BP-3 were detected at concentrations of 4.40-27.39 and < 0.020-0.560 ng/g w.w., respectively, indicating their widespread presence. Overall, our proposed method successfully detected UVACs in marine invertebrates, raising concerns regarding their potential environmental and health effects.

Exposure characteristics and cumulative risk assessment of bisphenol A and its substitutes: the Taiwan environmental survey for toxicants 2013.

Introduction: Ever since the use of bisphenol A (BPA) has been restricted, concerns have been raised regarding the use of its substitutes, such as bisphenol S (BPS) and bisphenol F (BPF). Meanwhile, the EU European Food Safety Authority (EFSA) issued the new tolerable daily intake (TDI) after the latest re-risk assessment for BPA, which enforced the need for cumulative risk assessment in the population. This study was conducted to identify BPA and its substitute's exposure characteristics of the general Taiwanese population and estimate the cumulative risk of bisphenol exposure. Methods: Urine samples (N = 366 [adult, 271; minor, 95]) were collected from individuals who participated in the Taiwan Environmental Survey for Toxicants 2013. The samples were analyzed for BPA, BPS, and BPF through ultraperformance liquid chromatography-tandem mass spectrometry. Daily intake (DI) levels were calculated for each bisphenol. Hazard quotients (HQs) were calculated with the consideration of tolerable DI and a reference dose. Additionally, hazard index (HI; sum of HQs for each bisphenol) values were calculated. Results: Our study found that the median level of BPA was significantly higher in adults (9.63 µg/g creatinine) than in minors (6.63 µg/g creatinine) (p < 0.001). The DI of BPS was higher in female (0.69 ng/kg/day) than in male (0.49 ng/kg/day); however, the DIs of BPF and BPS were higher in boys (1.15 and 0.26 ng/kg/day, respectively) than in girls (0.57 and 0.20 ng/kg/day, respectively). Most HI values exceeded 1 (99% of the participants) after EFSA re-establish the TDI of BPA. Discussion: Our study revealed that the exposure profiles and risk of BPA and its substitute in Taiwanese varied by age and sex. Additionally, the exposure risk of BPA was deemed unacceptable in Taiwan according to new EFSA regulations, and food contamination could be the possible source of exposure. We suggest that the risk of exposure to BPA and its substitutes in most human biomonitoring studies should be reassessed based on new scientific evidence.

Probabilistic risk assessment of dietary exposure to benzophenone derivatives in cereals in Taiwan.

Benzophenone (BP) and BP derivatives (BPDs) are widely used as ultraviolet (UV) stabilizers in food packaging materials and as photoinitiators in UV-curable inks for printing on food-contact materials. However, our knowledge regarding the sources and risks of dietary exposure to BP and BPDs in cereals remains limited, which prompted us to conduct this study. We measured the levels of BP and nine BPDs-BP-1, BP-2, BP-3, BP-8, 2-hydroxybenzophenone, 4-hydroxybenzophenone, 4-methylbenzophenone (4-MBP), methyl-2-benzoylbenzoate, and 4-benzoylbiphenyl-in three types of cereals (rice flour, oatmeal, and cornflakes; 180 samples in total). A Bayesian Markov-chain Monte Carlo (MC) simulation approach was used for deriving the posterior distributions of BP and BPD residues. This approach helped in addressing the uncertainty in probabilistic distribution for the sampled data under the detection limit. Through an MC simulation, we calculated the daily exposure levels of dietary BP and BPDs and corresponding health risks. The results revealed the ubiquitous presence of BP, BP-3, and 4-MBP in cereals. Older adults (aged >65 years) had the highest (97.5 percentile) lifetime carcinogenic risk for BP exposure through cereals (9.41 × 10-7), whereas children aged 0-3 years had the highest (97.5 percentile) hazard indices for BPD exposure through cereals (2.5 × 10-2). Nevertheless, across age groups, the lifetime carcinogenic risks of BP exposure through cereals were acceptable, and the hazard indices for BPD exposure through cereals were <1. Therefore, BPD exposure through cereals may not be a health concern for individuals in Taiwan.

Concentrations, compositional profiles, and health risks of benzophenones among the Taiwanese population based on analysis of 23 daily consumed foods.

In this study, we analyzed the occurrence and distribution of 11 benzophenone-type ultraviolet filters (BPs) in 893 food samples spanning 7 food categories in Taiwan. We conducted a Monte Carlo simulation to determine the carcinogenic and noncarcinogenic risks of BPs. The results indicated that cornflakes had the highest mean level of BPs (103 ng/g), followed by bread (101 ng/g) and pastries (59 ng/g). BP was the most prevalent category, followed by 4-methylbenzophenone (4-MBP), 2-hydroxybenzophenone, and benzophenone-3. Estimation of the lifetime cancer risk (LTCR) of BP (average life expectancy of 80 years) placed them in the 50th and 97.5th percentiles [P50 (P97.5)] LTCR of 1.9 × 10-7 (5.7 × 10-6), indicating that BP in food poses a low renal hazard to the Taiwanese population. The noncarcinogenic risk of BPs was evaluated using a hazard quotient and combined margin of exposure (MOET), revealing a P50 (P97.5) hazard index of < 1 for BP, 4-MBP, and methyl-2-benzoylbenzoate. Although the P50 MOET values for all age groups were within the moderate range of concern, with a more conservative extreme (P2.5), the MOET values for the 0-3, 3-6, and 6-12 age groups fell below 100, indicating a high concern for renal degeneration and hyperplasia.

Associations between paraben exposure, thyroid capacity, homeostasis and pituitary thyrotropic function in the general Taiwanese: Taiwan Environmental Survey for Toxicants (TEST) 2013.

Several studies have suggested that some endocrine disruptors such as synthetic phenols, parabens and phthalates may disrupt thyroid hormone signaling and associated negative feed-backs with the central hypothalamic-pituitary-thyroid (HPT) axis. Therefore, we investigated urinary paraben and blood thyroid hormone levels in the Taiwanese population. Our sample comprised 264 adults (aged 18-97 years) and 75 minors (aged 7-17 years) from Taiwan Environmental Survey for Toxicants 2013. Urinary levels of methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) were assessed. Hormones of particular interest include: thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4). We sought integrated parameters to describe the transfer of thyroid hormones in homeostatic models. The geometric mean urinary paraben levels of the adults were higher than those of the minors (adults vs. minors; MeP: 383 vs. 62.4 ng/mL; PrP: 109 vs. 8.00 ng/mL; EtP: 39.5 vs. 2.38 ng/mL, and BuP: 6.36 vs. 2.13 ng/mL). In the male adults, we discovered that 0.253% (p = 0.032), 0.256% (p = 0.041) and 0.257% (p = 0.037) decreases in the TSH, TSH/T4 and TSH/FreeT4 ratio was associated with 1% EtP increases, respectively. In the female minors, 0.093% (p = 0.044), 0.072% (p = 0.047) and 0.156 (p = 0.004) increases in the TSH ratios were associated with a 1% MeP, EtP and BuP increase, respectively. Moreover, 0.151% (p = 0.008) and 0.177% (p = 0.001) increases in TSH/T4 and TSH/free T4 ratios were associated with a BuP 1% increase, respectively. Finally, EtP was positively associated with SPINA-GT (ß: 15.66, p = 0.036) in the male adults. By contrast, EtP were positively associated with Jostel's TSH index and sTSHI (ß: 0.072, p = 0.049; ß: 0.107, p = 0.049) in the female minors. The Taiwanese population is commonly exposed to parabens, which can potentially lead to alteration of thyroid hormone homeostasis.

Dietary risk assessment of benzophenone derivatives using bread consumption estimates in a Taiwanese population.

Listed as endocrine-disrupting chemicals, benzophenone (BP) and its nine analogues (BPs) are an emerging group of contaminants. The migration of BPs from ultraviolet inks to food has been investigated in many studies; however, few studies have investigated BPs in foods and the risks of human exposure to BPs. We validated a trace and multi-residue method for simultaneously determining 10 BPs, including BP, BP-1, BP-2, BP-3, BP-8, 4-MBP, 2-OHBP, 4-OHBP, M2BB, and PBZ. Eighty-one bread samples were analyzed using stable isotope labeling and ultrahigh-performance liquid chromatography-electrospray ionization tandem mass spectrometry with solid-liquid extraction. We determined the estimated daily intake of BPs, non-cancer risks, and lifetime cancer risks (LTCRs) from daily bread consumption for seven age groups using a Monte Carlo simulation. The method demonstrated robust linearity (R2 ≥ 0.991), low limits of detection (0.04-2 ng/g), and satisfactory precision. The intra- and interday relative standard deviation ranges were 0.6%-9% and 3%-20%, respectively. BP, 4-MBP, 2-OHBP, BP-1, and BP-3 were detected in 97%, 67%, 59%, 24%, and 23% of the samples, respectively. 2-OHBP had the highest mean (range) value of 18.3 (

Data on lung and intestinal microbiome after air pollution exposure in ageing rats.

Air pollution has been linked to respiratory diseases, and urban air pollution can be attributed to a number of emission sources. The emitted particles and gases are the primary components of air pollution that enter the lungs during respiration. Particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5) can deposit deep into the respiratory tract via inhalation and has been proposed as a causative agent for adverse respiratory health. In addition, the lung contains a diverse microbial community (microbiome) that maintains normal homeostasis and is significantly altered in a variety of pulmonary disorders. Air pollution, specifically PM2.5, has previously been shown to significantly alter the composition of the lower airway microbiome, which has been linked to decreased lung function in chronic obstructive pulmonary disease (COPD) patients. Surprisingly, the intestinal microbiome has also been implicated in the modulation of pulmonary inflammatory diseases. Therefore, dysbiosis of the lung and intestinal microbiomes pose significant negative effects on human health. This dataset describes the microbial community profiles of the lungs and intestines of ageing rats exposed to ambient unconcentrated traffic-related air pollution for three months. The whole-body exposure system was equipped with and without high efficiency particulate air (HEPA) filtration (gaseous vs. PM2.5 pollution). The data can provide valuable information on lung and intestinal microbiome changes, including that which was only found after traffic-related air pollution exposure.

Distribution and toxicity of submicron plastic particles in mice.

Although microplastics (MPs) have become a global issue, the biodistribution and toxicities of MPs were still unclear. In this study, c57BL/6 mice were treated with submicron-sized MPs labeled with Nile red fluorescence by oral gavage three times a week for four consecutive weeks. Flow cytometry and microscopy technique were used to examine the concentration and distribution of MPs in various tissues and biofluids. The oxidative stress and inflammation were assessed via liquid chromatography-mass spectrometry and enzyme-linked immunosorbent assay, respectively. Submicron-sized MP signals were found in the intestines, liver, spleen, kidney, lungs, blood, and urine of mice after MP exposure. Increased oxidative stress in mouse urine and elevated inflammatory cytokines in mouse kidney were also recorded. In conclusion, flow cytometry is a useful tool for examining the number concentrations of MPs. Increased oxidative stress and inflammation after MP treatment indicates that the toxicity of MP warrants further investigation.

Oxidative/nitrosative stress increased the risk of recurrent pregnancy loss-Taiwan Recurrent Pregnancy Loss and Environmental Study (TREPLES).

OBJECTIVE: Oxidative stress biomarkers (OSBs) may be strongly associated with disease progression and recurrent pregnancy loss (RPL). However, the research on associations of most OSBs (e.g., 8-nitroguanine [8-NO2Gua] and 4-hydroxy-2-nonenal-mercapturic acid [HNE-MA]) with RPL is limited. Therefore, we aimed to investigate the effect of OSBs exposure on RPL risk by performing a case-control study. MATERIAL AND METHODS: We use our established dataset, Taiwan Recurrent Pregnancy Loss and Environmental Study (TREPLES), which included 514 Taiwanese reproductive age women (aged 20-50 years; 397 cases and 117 controls) from National Cheng Kung University Hospital. RPL is clinically defined by a history of two or more consecutive miscarriages, where a miscarriage is defined as the termination of pregnancy before 20 weeks of gestation. The urinary levels of several OSBs (e.g., 8-hydroxy-2'-deoxyguanosine [8-OHdG], 8-NO2Gua, 8-isoprostaglandin F2α [8-isoPGF2α], and HNE-MA) and malondialdehyde (MDA) were measured using isotope dilution liquid chromatography-tandem mass spectrometry and thiobarbituric acid reactive substances, respectively. RESULTS: The median levels of 8-NO2Gua (6.15 vs. 3.76 ng/mL) and HNE-MA (30.12 and 21.54 ng/mL) were significantly higher in the RPL group than in the control group. By categorizing the OSBs data into tertiles, after we adjusted for age and urine creatinine levels discovered that the RPL risk associated with 8-NO2Gua and HNE-MA levels in the third tertile were approximately 2 times higher than those in the first tertile (8-NO2Gua, adjusted OR = 3.27, 95 % CI = 1.66-6.43; HNE-MA, adjusted OR = 1.96, 95 % CI = 1.05-3.64; p < 0.05). These findings suggest that the oxidative stress biomarkers of 8-NO2Gua and HNE-MA are risk factors for RPL. CONCLUSION: Our findings indicate that specific OSBs are associated with an increased RPL risk, suggesting that reducing OSB levels can improve RPL risk. Nevertheless, more studies on preventive medicine are required to understand the exposure sources and adverse outcome pathways of OSBs associated with RPL.

Effects of antibiotics and metals on lung and intestinal microbiome dysbiosis after sub-chronic lower-level exposure of air pollution in ageing rats.

We investigated the effects of antibiotics, drugs, and metals on lung and intestinal microbiomes after sub-chronic exposure of low-level air pollution in ageing rats. Male 1.5-year-old Fischer 344 ageing rats were exposed to low-level traffic-related air pollution via whole-body exposure system for 3 months with/without high-efficiency particulate air (HEPA) filtration (gaseous vs. particulate matter with aerodynamic diameter of ≤2.5 µm (PM2.5) pollution). Lung functions, antibiotics, drugs, and metals in lungs were examined and linked to lung and fecal microbiome analyses by high-throughput sequencing analysis of 16 s ribosomal (r)DNA. Rats were exposed to 8.7 µg/m3 PM2.5, 10.1 ppb NO2, 1.6 ppb SO2, and 23.9 ppb O3 in average during the study period. Air pollution exposure decreased forced vital capacity (FVC), peak expiratory flow (PEF), forced expiratory volume in 20 ms (FEV20), and FEF at 25∼75% of FVC (FEF25-75). Air pollution exposure increased antibiotics and drugs (benzotriazole, methamphetamine, methyl-1 H-benzotriazole, ketamine, ampicillin, ciprofloxacin, pentoxifylline, erythromycin, clarithromycin, ceftriaxone, penicillin G, and penicillin V) and altered metals (V, Cr, Cu, Zn, and Ba) levels in lungs. Fusobacteria and Verrucomicrobia at phylum level were increased in lung microbiome by air pollution, whereas increased alpha diversity, Bacteroidetes and Proteobacteria and decreased Firmicutes at phylum level were occurred in intestinal microbiome. Lung function decline was correlated with increasing antibiotics, drugs, and metals in lungs as well as lung and intestinal microbiome dysbiosis. The antibiotics, drugs, and Cr, Co, Ca, and Cu levels in lung were correlated with lung and intestinal microbiome dysbiosis. The lung microbiome was correlated with intestinal microbiome at several phylum and family levels after air pollution exposure. Our results revealed that antibiotics, drugs, and metals in the lung caused lung and intestinal microbiome dysbiosis in ageing rats exposed to air pollution, which may lead to lung function decline.

Are Phthalate Exposure Related to Oxidative Stress in Children and Adolescents with Asthma? A Cumulative Risk Assessment Approach.

Childhood asthma has become one of the most common chronic diseases in children and adolescents. However, few case-control studies investigating the relationship between phthalate exposure and asthma in children and adolescents have been conducted, especially in Asia. Therefore, we assessed the potential associations between phthalate exposure and asthma among children and adolescents in Taiwan. Because various demographic and environmental variables may influence the incidence and prognosis of asthma, we performed a case-control study with propensity score matching. Out of 615 Childhood Environment and Allergic Diseases Study participants, we conditionally matched 41 children with clinically diagnosed asthma with 111 controls. We then analyzed 11 phthalate metabolites by using liquid chromatography with tandem mass spectrometry. Compared with the control group, the median urinary phthalate levels for most phthalate metabolites in the case group were slightly increased, including monomethyl phthalate, mono-n-butyl phthalate, monobenzyl phthalate, monoethylhexyl phthalate, mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, mono-(2-ethyl-5-carboxypentyl) phthalate, and mono-(2-carboxymethylhexyl) phthalate. Hence, our results suggest that phthalate exposure may be associated with the development of asthma. In addition, prenatal environmental factors, such as active or passive smoking during pregnancy, may increase the risk of asthma.

Cumulative risk assessment and exposure characteristics of parabens in the general Taiwanese using multiple hazard indices approaches.

Parabens, a group of endocrine disrupting chemicals (EDCs), are well known preservatives in pharmaceuticals and personal care products (PPCPs). However, studies on parabens exposure and their cumulative effects in Asian population are limited. This study aimed to identify the exposure characteristics and estimate the cumulative risk of four parabens in the general Taiwanese. We have collected urine samples including 271 adults (18-97 yrs old) and 95 minors (7-17 yrs old), from Taiwan Environmental Survey for Toxicants 2013, and analyzed for four urinary parabens including methyl (MeP)-, ethyl (EtP)-, propyl (PrP)-, and butylparaben (BuP) by using ultraperformance liquid chromatography-tandem mass spectrometry. The health-based guidance value (HBGV) and the antiandrogenic properties of parabens were used to calculate the hazard index (HI) for cumulative risk. MeP and PrP were most abundant compounds and startlingly higher than those in other countries. Adults had a higher geometric mean level of four parabens than minors (adults: MeP, 381.7; PrP, 108.6; EtP, 39.6 and BuP 6.3 ng/mL; minors: MeP, 65.7; PrP, 7.9, EtP, 2.6 and BuP 2.2 ng/mL). Participants who used a higher number of personal care products had a significantly higher risk with higher concentrations of PrP (above 75th %tile) [adjusted odds ratio (aOR): 1.79, 95 % CI: 1.01-3.15] and BuP [aOR: 1.78, 95 % CI: 1.03-3.07]. The median and 95th %tile HI (the sum of the HQs of each paraben) was as 1.10 and 4.39-fold higher than acceptable cumulative threshold (HI <1) and PrP accounted for 90 % of the HI. Our results indicate omnipresent exposure to parabens among the Taiwanese population, which might cause certain level of concerns. These significant increasing trends of HI with age dependence were observed, which mainly driven by PPCPS used. Routine survey of parabens in PPCPs and continued biomonitoring needs to be urgently addressed.

Phthalate Exposure and Oxidative/Nitrosative Stress in Childhood Asthma: A Nested Case-Control Study with Propensity Score Matching.

Whether low-dose phthalate exposure triggers asthma among children, and its underlying mechanisms, remain debatable. Here, we evaluated the individual and mixed effects of low-dose phthalate exposure on children with asthma and five (oxidative/nitrosative stress/lipid peroxidation) mechanistic biomarkers-8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-nitroguanine (8-NO2Gua), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA), 8-isoprostaglandin F2α (8-isoPF2α), and malondialdehyde (MDA)-using a propensity score-matched case-control study (case vs. control = 41 vs. 111). The median monobenzyl phthalate (MBzP) concentrations in the case group were significantly higher than those in the control group (3.94 vs. 2.52 ng/mL, p = 0.02), indicating that dust could be an important source. After adjustment for confounders, the associations of high monomethyl phthalate (MMP) (75th percentile) with 8-NO2Gua (adjusted odds ratio (aOR): 2.66, 95% confidence interval (CI): 1.03-6.92) and 8-isoPF2α (aOR: 4.04, 95% CI: 1.51-10.8) and the associations of mono-iso-butyl phthalate (MiBP) with 8-isoPF2α (aOR: 2.96, 95% CI: 1.13-7.79) were observed. Weighted quantile sum regression revealed that MBzP contributed more than half of the association (56.8%), followed by MiBP (26.6%) and mono-iso-nonyl phthalate (MiNP) (8.77%). Our findings supported the adjuvant effect of phthalates in enhancing the immune system response.

Relationships among phthalate exposure, oxidative stress, and insulin resistance in young military soldiers: A cumulative risk assessment and mediation approach.

BACKGROUND: Epidemiological studies concerning whether oxidative stress mediates phthalate exposure-insulin resistance (IR) associations in young adults are limited. Therefore, we investigated this potential mediation by using a cumulative risk approach involving daily intake (DI) and a hazard index (HIRfD). METHODS: The participants were 391 Taiwanese military personnel. This study measured their IR (as homeostatic model assessment of estimated IR [HOMA-IR]), levels of oxidative stress biomarkers (8-hydroxy-2-deoxyguanosine, 8-nitroguanine, 8-iso-prostaglandin F2α, and N-acetyl-S-[tetrahydro-5-hydroxy-2-pentyl-3-furanyl]-L-cysteine [HNE-MA]), the sum of these four biomarkers (ΣOS), and urinary phthalate metabolite concentrations. The HIRfD was estimated on the basis of urinary levels of phthalate metabolite, and the DI of five phthalates was determined: dimethyl phthalate, benzyl butyl phthalate (BBzP), diethyl phthalate, dibutyl phthalate (DBP), and di (2-ethylhexyl) phthalate (DEHP). Logistic regression models were employed to explore associations among DI, HIRfD, oxidative stress biomarkers, and HOMA-IR values. The role played by oxidative stress in the phthalate exposure-HOMA-IR association was determined using mediation analysis. RESULTS: We discovered positive associations between high DI of DBP, BBzP, and DEHP; high HIRfD; and high ΣOS. High ΣOS and HNE-MA were associated with a higher likelihood of a high HOMA-IR value. Mediation analysis indicated that high ΣOS and HNE-MA were significant mediators of the associations between phthalates and IR. CONCLUSION: Oxidative stress may partially mediate the phthalate-IR relationship in young adults.

Determining the trace-level photoinitiators in juices and milk from various types of packages in Taiwan by a micro-QuEChERS-based UPLC-MS/MS.

The distribution of 16 photoinitiators (PIs)-benzophenone (BP) and its five derivatives, 4-methylbenzophenone (4-MBP), methyl-2-benzoylbenzoate (M2BB), 2-ethylhexyl-4-dimethylaminobenzoate (EHDAB), and the other 7 PIs-in packaged juice and milk was assessed using an UPLC-MS/MS with micro-QuEChERS. The validated method demonstrated robust linearity (≥0.9908), LOQs (juice: 0.006-7.26 ng/mL; milk: 0.004-7.14 ng/mL), intra- and inter-day accuracy (93.1%-110.1% for juice and 66.8%-114.6% for milk with relative standard deviations (RSDs) of ≤16.8%), and matrix effect with RSDs of ≤14.8%. BP exceeded the LOQ in 100% of 136 packaged juice (14.22 ± 7.60 ng/mL) and 51 milk (8.45 ± 3.25 ng/mL) samples, and the quantitation rates for M2BB and EHDAB in packaged juice were 100%. Notably, the 4-MBP in both juice and milk was significantly related to the packaging material. The method has been successfully applied to evaluate the occurrence and distribution of PIs in packaged juice and milk.

Associations between Oxidative/Nitrosative Stress and Thyroid Hormones in Pregnant Women-Tainan Birth Cohort Study (TBCS).

Oxidative and nitrosative stress have been linked to thyroid function in both animal and human studies. In the present study, the associations between oxidative and nitrosative stress and thyroid hormones were investigated. Measurements were obtained from 97 Taiwanese pregnant women at the first, second, and third trimesters. Levels of five oxidative and nitrosative stress biomarkers (8-hydroxy-2'-deoxyguanosine [8-OHdG], 8-nitroguanine [8-NO2Gua], 4-hydroxy-2-nonenal-mercapturic acid [HNE-MA], 8-isoprostaglandin F2α [8-isoPGF2α], and malondialdehyde [MDA]) were measured using urine samples, and levels of five thyroid hormones (triiodothyronine [T3], thyroxine [T4], free T4, thyroid-stimulating hormone [TSH], and T4-binding globulin [TBG]) were measured in blood samples. Multiple linear regressions and linear mixed-model regressions were conducted to determine the associations between oxidative or nitrosative stress biomarkers and thyroid hormones in pregnant women. We found that TSH was negatively and significantly associated with 8-NO2Gua (-14%, 95% CI [-26.9% to -1.1%]) and HNE-MA (-23%, 95% CI [-35.9% to -10.0%]) levels. However, T4 (3%, 95% CI [0.2%-5.8%]) and free T4 (4.3%, 95% CI [0.8%-7.8%]) levels were positively and significantly associated with 8-NO2Gua. The T4 to TBG and free T4 to TBG ratios were positively and significantly associated with 8-NO2Gua level (T4/TBG: 3.6%, 95% CI [0.5%-6.7%]; free T4/TBG: 5.6%, 95% CI [0.2%-11.1%]). However, the TSH to T4 ratio was negatively and significantly associated with 8-NO2Gua level (-17.3%, 95% CI [-30.4% to -4.3%]). The T3 to TSH ratio was positively and significantly associated with HNE-MA level (25.2%, 95% CI [11.2%-39.2%]). However, the TSH to T4 and TSH to free T4 ratios were negatively and significantly associated with HNE-MA level (TSH/T4: -21.2%, 95% CI [-34.5% to -7.8%] and TSH/free T4: -24.0%, 95% CI [-38.3% to -9.6%]). Our findings suggest that an imbalance of oxidative and nitrosative stress may alter thyroid hormone homeostasis during pregnancy. Disruption of the maternal thyroid homeostasis during pregnancy would affect embryonic and fetal development.

Determination of Parabens, Bisphenol A and Its Analogs, Triclosan, and Benzophenone-3 Levels in Human Urine by Isotope-Dilution-UPLC-MS/MS Method Followed by Supported Liquid Extraction.

The development of a rapid analytical approach for determining levels of antibacterial agents, plasticizers, and ultraviolet filters in biosamples is crucial for individual exposure assessment. We developed an analytical method to determine the levels of four parabens-bisphenols A (BPA) and its analogs, triclosan (TCS), triclocarban, and benzophenone-3 (BP-3)-in human urine. We further measured the levels of these chemicals in children and adolescents. We used a supported liquid extraction (SLE) technique coupled with an isotope-dilution ultraperformance liquid chromatography-tandem mass spectrometry (ID-UPLC-MS/MS) method to assess the detection performance for these chemicals. Forty-one urine samples from 13 children and 28 adolescents were assessed to demonstrate the capability and feasibility of our method. An acceptable recovery (75.6-102.4%) and matrix effect (precision < 14.2%) in the three-level spiked artificial urine samples were achieved, and good performance of the validated ID-UPLC-MS/MS method regarding linearity, limits of detection, and quantitation was achieved. The within-run and between-run accuracy and precision also demonstrated the sensitivity and stability of this analytical method, applied after SLE. We concluded that the ID-UPLC-MS/MS method with SLE pretreatment is a valuable analytical method for the investigation of urinary antibacterial agents, plasticizers, and ultraviolet filters in humans, useful for human biomonitoring.

Cumulative Dietary Risk Assessment of Benzophenone-Type Photoinitiators from Packaged Foodstuffs.

Photoinitiators used in ultraviolet-cured ink may migrate from food packaging materials into food products. Therefore, we conducted a dietary risk assessment of exposure to benzophenone (BP)-type photoinitiators by quantifying and reducing uncertainties associated with the risk characterization. A total of 362 food packaging samples including 180 cereals, 136 fruit and vegetable juices, and 46 milk samples were subjected to fast pesticides extraction to determine photoinitiator residues. The average daily dose (ADD) of BP was the highest in the age group of zero to three years, with a P97.5 ADD of 2.56 × 10-4 mg/kg bw/day. The ADD of 2-hydroxybenzophenone (2-OHBP) was the highest in the age group of three to six years, with a P97.5 UB ADD of 3.52 × 10-5 mg/kg bw/day. The estimated UB P97.5 ADD for each age group was below the toxicological concern threshold of 0.0015 mg/kg bw/day. The cumulative toxicity of all BPs, evaluated using the MOET value, was at an acceptable level. Although the MOET value of BPs was above the safety limit in the foodstuffs studied herein, this result may be different if Taiwan were to follow regulation guidelines for BP-type photoinitiators based on the specific migration limit for the unmeasured BP residues in other foodstuffs.