Phthalates are used in industry products, household items, and medical tools as plasticizers. Human exposure to phthalates has raised concern about its toxicity. In the present study, optimization ...was conducted for the simultaneous analysis of eight kinds of phthalate metabolites using gas chromatography–mass spectrometry (GC-MS): MEP, MiBP, MnBP, MBzP, MiNP, MEHP, MEOHP, and MEHHP. In order to minimize the matrix effect and to do quantitative analysis, isotope dilution and LLE-GC-MS methods were performed. Urine samples were enzymatically hydrolyzed, extracted with a mixture of n-hexane and ethyl ether (8:2; v:v), and subsequently derivatized with trimethylsilylation. All eight kinds of analytes showed clear resolution and high reproducibility in GC-MS results. The method detection limit ranged from 0.05ng/mL to 0.2ng/mL. Calibration curves were found to be linear from 0.2 to 100ng/mL with –2>0.992. The relative standard deviation of the intraday precision using water and urine ranged from 2.1% to 16.3%. The analysis was performed with urine samples that were collected from adults residing in the Republic of Korea. The analyzed concentration results were compared according to gender and region. As a result, DEHP metabolites showed the highest detected concentration (75.92μg/g creatinine, 100%), and MiNP, a metabolite of DiNP, showed the lowest detected concentration (0.42μg/g creatinine, 22.5%). On average, female urine (200.76μg/g creatinine) had a higher detected concentration of ∑8 phthalate metabolites than male urine. Samples from rural regions (211.96μg/g creatinine) had higher levels than samples from urban regions.
Scheme. Diagram of extraction and derivatization of 8 metabolites of phthalates in urine. Display omitted
•We have established LLE-GC-MS method for analysis of urinary phthalate metabolites.•TMS derivatization was performed for GC-MS analysis.•MDL was calculated to be 0.05–0.2ngmL−1, and precision was less than 16%.•We analyzed 8 kinds of urinary phthalate metabolites in urine of Korean residents.•The correlation analysis was performed for the metabolite of DEHP.
We developed a colorimetric method for measuring the amount of oil in mouse stool after co-administering an oil-soluble dye. When the amount of oil in the feces calculated from the amounts of Sudan ...III and Oil Red O was plotted against the amount of oil detected by liquid chromatography–mass spectrometry, the graph was linear, showing a one-to-one correlation between two analyses. This method may be utilized to determine the efficacy of lipase inhibitors, or to assess fat malabsorption in vivo.
Hair follicles are among the most highly proliferative tissues. Polyamines are associated with proliferation, and several polyamines including spermidine and spermine play anti‐inflammatory roles. ...Androgenic alopecia results from increased dihydrotestosterone metabolism, and alopecia areata is an autoimmune disease. This study aimed to investigate differences in polyamine profiles in hair samples between patients with androgenic alopecia and alopecia areata. Polyamine concentrations were determined through high‐performance liquid chromatography‐mass spectrometry. Hair samples were derivatized with isobutyl chloroformate. Differences in polyamine levels were observed between androgenic alopecia and alopecia areata compared with normal controls. In particular, polyamine levels were higher in alopecia areata patients than in normal controls. Certain polyamines displayed different concentrations between the androgenic alopecia and alopecia areata groups, suggesting that some polyamines, particularly N‐acetyl putrescine (P = 0.007) and N‐acetyl cadaverine (P = 0.0021), are significantly different in androgenic alopecia. Furthermore, spermidine (P = 0.021) was significantly different in alopecia areata. Our findings suggest that non‐invasive quantification of hair polyamines may help distinguish between androgenic alopecia and alopecia areata. Our study provides novel insights into physiological alterations in patients with androgenic alopecia and those with alopecia areata and reveals some differences in polyamine levels in hair loss diseases with two different modes of action.
Di(2-ethylhexyl) phthalate (DEHP) is one of the common phthalate plasticizers used primarily in soft polyvinyl chloride, which is a plastic polymer that makes up the total weight of goods from 1% up ...to 40% in many consumer products. The aims of this study were to examine the urinary DEHP metabolites in South Korean children and to investigate the correlation between mother and child DEHP urine excretion. Three kinds of urinary DEHP metabolites: mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (5-OH-MEHP) and mono(2-ethyl-5-oxohexyl) phthalate (5-oxo-MEHP), were analyzed. The total of 954 samples (nChildren=392, nMothers=265, nAadults=297), including 258 mother and child pairs, were analyzed using isotope dilution gas chromatography–mass spectrometry. Many studies present higher concentration of DEHP metabolites detected from adults in reproductive age than adults in other ages. Therefore, adults who are age-matched to mothers were evaluated to serve as a standard of comparison against mothers. All statistical analysis was made by adjusting detected volume concentrations (μg/L) with respect to creatinine concentrations (mg/dL) since urinary DEHP metabolites were studied using human reference. The difference in median levels of sum of urinary DEHP metabolites was only significant when children were analyzed in relation to region (p-value≤0.005). Among the three DEHP metabolites, only MEHP of children was significantly correlated to that of paired mothers (p-value≤0.01). The present paper defines the relative metabolic rate (RMR) of DEHP metabolism for the first time in study on phthalates. Children had faster RMR than mothers and adults, specifically in the first step of DEHP metabolism (RMR1: MEHP hydroxylation to 5-OH-MEHP), and RMR1 of children between 1 and 24months was the fastest. The above results may be used to study and assess human health risk from DEHP exposures, especially among mothers and children in Korea.
► Children have faster relative metabolic rate of DEHP metabolism than mothers and children under 2 years is the fastest. ► Mothers have higher urinary DEHP metabolite concentrations than age matched female adults. ► .DEHP exposure of mothers is independent from that of children. ► .Rural boys have higher DEHP metabolite concentrations than urban boys.
Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease that is frequently found in athletes and those who have experienced repetitive head traumas. CTE is associated with a variety of ...neuropathologies, which cause cognitive and behavioral impairments in CTE patients. However, currently, CTE can only be diagnosed after death via brain autopsy, and it is challenging to distinguish it from other neurodegenerative diseases with similar clinical features. To better understand this multifaceted disease and identify metabolic differences in the postmortem brain tissues of CTE patients and control subjects, we performed ultra-high performance liquid chromatography–mass spectrometry (UPLC-MS)-based non-targeted metabolomics. Through multivariate and pathway analysis, we found that the brains of CTE patients had significant changes in the metabolites involved in astrocyte activation, phenylalanine, and tyrosine metabolism. The unique metabolic characteristics of CTE identified in this study were associated with cognitive dysfunction, amyloid-beta deposition, and neuroinflammation. Altogether, this study provided new insights into the pathogenesis of CTE and suggested appealing targets for both diagnosis and treatment for the disease.
Metabolites reflect the biochemical dynamics for the maintenance of pregnancy and parturition. UPLC-Q/TOF-MS and LC-MS/MS metabolomics were performed to identify and validate the plasma metabolomic ...signatures of preterm birth (PTB). We recruited pregnant women between 16 and 40 weeks 5 days gestational age at Ewha Womans Mokdong Hospital for a nested case-control study. In untargeted UPLC-Q/TOF-MS, score plots of partial least-squares discriminant analysis clearly separated the PTB group from the term birth (TB, n = 10; PTB, n = 11). Fifteen metabolites were significantly different between the two groups, as indicated by a variable importance in projection >1 and p < 0.05. Metabolic pathways involving retinol, linoleic acid, D-arginine, and D-ornithine were associated with PTB. Verification by LC-MS/MS focused on retinol metabolism (TB, n = 39; PTB, n = 20). Retinol levels were significantly reduced in PTB compared to TB, while retinal palmitate, all-trans-retinal, and 13-cis-retinoic acid (13cis-RA) significantly increased (p < 0.05). Retinol-binding protein levels were also elevated in PTB. Additionally, all-trans-retinal (AUC 0.808, 95% CI: 0.683–0.933) and 13cis-RA (AUC 0.826, 95% CI: 0.723–0.930) showed improved predictions for PTB-related retinol metabolites. This study suggests that retinoid metabolism improves the accuracy of PTB predictions and plays an important role in maintaining pregnancy and inducing early parturition.
Male pattern baldness (MPB) has been associated with dihydrotestosterone (DHT) expression. Finasteride treats MPB by inhibiting 5-alpha reductase and blocking DHT production. In this study, we aimed ...to identify metabolic differences in urinary metabolomics profiles between MPB patients after a one-year treatment with finasteride and healthy controls. Untargeted and targeted metabolomics profiling was performed using liquid chromatography-mass spectrometry (LC-MS). We hypothesized that there would be changes in overall metabolite concentrations, especially steroids, in the urine of hair loss patients treated with finasteride and normal subjects. Untargeted analysis indicated differences in steroid hormone biosynthesis. Therefore, we conducted targeted profiling for steroid hormone biosynthesis to identify potential biomarkers, especially androgens and estrogens. Our study confirmed the differences in the concentration of urinary androgens and estrogens between healthy controls and MPB patients. Moreover, the effect of finasteride was confirmed by the DHT/T ratio in urine samples of MPB patients. Our metabolomics approach provided insight into the physiological alterations in MPB patients who have been treated with finasteride for a year and provided evidence for the association of finasteride and estrogen levels. Through a targeted approach, our results suggest that urinary estrogens must be studied in relation to MPB and post-finasteride syndrome.
Chemical accidents have frequently occurred in South Korea as a result of the huge amount of chemicals being used in various industries. Even though fire accidents accounted for 71.9% of chemical ...accidents during 2008–2018 in South Korea, most ecological research and investigation has focused on leakage accidents since most fire or explosion gases are diffused out and disappear into the atmosphere. In this study, the possibility of soil contamination by toluene combustion is proposed. A fire simulation batch test was performed and identified the combustion by-products such as methylbenzene, ethylbenzene, ethynylbenzene, benzaldehyde, 1-phenyl-1-propyne, naphthalene, 2-methylindene using gas chromatography coupled with mass spectrometry (GC–MS). Naphthyl-2-methyl-succinic acid, a metabolic intermediate of naphthalene metabolism derived from the combustion product of toluene, was also discovered in field soil and the secondary metabolites such as streptomycin 6-phosphate, 3-Nitroacrylate, oxaloacetate using LC–MS. Moreover, Streptomyces scabiei, participating in naphthalene metabolism, was also discovered in filed soil (contaminated soil) using 16s rRNA sequencing. As a result, bacterial stress responses in field soil (contaminated soil) affected by gas cloud were identified by discovering metabolites relating to bacterial self-defense action such as fatty biosynthesis. This study draws a conclusion that soil can be polluted enough to affect bacteria by gas cloud and soil bacteria and can encounter stress for a long term even though toluene and its combustion products had already decomposed in soil.
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