11 research outputs found
Analysis of an Alanine/Arginine Mixture by Using TLC/FTIR Technique
We applied TLC/FTIR coupled with mapping technique to analyze an alanine/arginine mixture. Narrow band TLC plates prepared by using AgI as a stationary phase were used to separate alanine and arginine. The distribution of alanine and arginine spots was manifested by a 3D chromatogram. Alanine and arginine can be successfully separated by the narrow band TLC plate. In addition, the FTIR spectra of the separated alanine and arginine spots on the narrow band TLC plate are roughly the same as the corresponding reference IR spectra
Personal exposure to fine particles (PM2.5) and respiratory inflammation o common residents in Hong Kong
Background: Given the lack of research on the personal exposure to fine particles (PM2.5) in Hong Kong, we examined the association between short-term personal exposure to PM2.5 and their constituents and inflammation in exhaled breath in a sample of healthy adult residents
Detection and Occurrence of Chlorinated Byproducts of Bisphenol A, Nonylphenol, and Estrogens in Drinking Water of China: Comparison to the Parent Compounds
This study applied a sensitive dansylation LC-MS/MS method
to the investigation on the occurrence of bisphenol A (BPA), nonylphenol
(NP), estrogens (E1 and E2), and their 11 chlorinated byproducts in
62 drinking water treatment plants (DWTPs) of 31 major cities across
China. BPA (4.7–512 ng/L), NP (8.2–918 ng/L), and E1
(ND-9.9 ng/L) were widely detected in source waters, E2 was detected
in less than half of the samples (ND-3.2 ng/L), while chlorinated
byproducts were only detected in source waters of two DWTPs. In drinking
water, chlorinated BPAs and monochloro-NP (MCNP) were detected in
more than half of the samples with concentrations of 0.2–26.7
ng/L for monochloro-BPA (MCBPA), ND-6.3 ng/L for dichloro-BPA (DCBPA),
ND-7.7 ng/L for trichloro-BPA (TCBPA), ND-4.8 ng/L for tetrachloro-BPA
(TBBPA), and ND-13.3 ng/L for MCNP, while dichloro-E1 (DCE1, ND-0.2
ng/L) and dichloro-NP (DCNP, ND-1.6 ng/L) were less frequently detected
(10/62 and 4/62). The production of chlorinated NPs in DWTPs was mainly
influenced by the amount of NP in source water and chlorine added,
while the concentrations of chlorinated BPAs in drinking waters were
only found to be significantly correlated with those of BPA in source
waters. Advanced treatment processes could be effective techniques
for reducing target chlorinated byproducts in drinking water. This
is the first report on the occurrence of chlorinated byproducts of
BPA, NP, and estrogens in drinking water, and these chemicals should
be considered when assessing the human risk of their parent compounds
Modulation of Benzo[a]pyrene-Induced Toxic Effects in Japanese Medaka (<i>Oryzias latipes</i>) by 2,2′,4,4′-Tetrabromodiphenyl Ether
Because polycyclic
aromatic hydrocarbons (PAHs) and polybrominated
diphenylethers (PBDEs) are ubiquitous and coexist in the environment
and in wildlife, there are potential interactions between them that
could cause toxic effects. In this study, the modulating effects of
2,2′,4,4′-tetrabromodiphenyl ether (BDE47) and benzo[a]pyrene
(BaP)-induced reproductive and developmental toxic effects in Japanese
medaka (Oryzias latipes) were investigated
by exposing adult Japanese medaka to BaP alone, BDE47 alone, and coexposing
them with both BaP and BDE47 at different concentrations, respectively.
Exposure to BaP alone significantly suppressed fecundity and egg protein
content and markedly induced skeletal deformation in F1 generation
eleutheroembryos. BDE47 significantly recovered reproductive functions,
fecundity, and egg protein content, suppressed by BaP when the concentration
of BDE47 increased to 0.44 μg/L. Such effects can be at least
partly explained by the decreased BaP levels in the coexposure groups
and the accompanying increase in the circulating level of 17β-estradiol
in female medaka fish. The prevalence of skeletal deformations markedly
increased to 19.3 ± 2.4% and 16.0 ± 1.6% in fish coexposed
to BaP and BDE47 at 0.44 and 2.58 μg/L compared with that of
fish exposed to 1.21 μg/L BaP alone (9.7 ± 1.7%), and the
impacts on male medaka fish in the coexposure groups would be the
crucial reason leading to these effects. Considering that the measured
water concentrations of BaP and BDE47 in the present study were comparable
with those reported in rivers and harbors, BaP and BDE47 contamination
in the real world would have a significant level of interactive effects
on wild fish
Levels of Phthalate Metabolites in Urine of Pregnant Women and Risk of Clinical Pregnancy Loss
Toxicological
studies have shown that phthalate esters (PAEs),
a class of widely used and environmentally prevalent chemicals, can
increase the abortion rate in animals, but epidemiological evidence
is scarce. This study aimed to explore the relationship between the
urinary concentration of phthalate metabolites and the risk of clinical
pregnancy loss. A total of 132 women who underwent clinical pregnancy
loss (cases) and 172 healthy pregnant women (controls) were recruited
from Beijing, China. Eight phthalate metabolites in urine were determined
by ultraperformance liquid chromatography tandem mass spectrometry
(UPLC–MS/MS). Five phthalate metabolites, monomethyl phthalate
(MMP), monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), mono-<i>n</i>-butyl phthalate (MnBP), and mono(2-ethlyhexyl) phthalate
(MEHP), were detected in at least 95% of the urine samples, with the
highest median concentration of 51.0 μg/g of creatinine for
MnBP of all participants. The differences in urinary concentrations
of phthalate metabolites between cases and controls were evaluated
using the Mann–Whitney <i>U</i> test. The concentrations
of MEP (median of 18.7 μg/g of creatinine), MiBP (23.3 μg/g
of creatinine), and MnBP (58.2 μg/g of creatinine) detected
in the cases were significantly higher than those (15.7 μg/g
of creatinine for MEP, 19.4 μg/g of creatinine for MiBP, and
43.9 μg/g of creatinine for MnBP) in the controls (<i>p</i> < 0.05). Increasing risks of clinical pregnancy loss were observed
from the first to fourth quartiles of the MEP, MiBP, and MnBP concentrations
(<i>p</i> < 0.05 for trend). We concluded that exposure
to MEP, MiBP, and MnBP was associated with an increased risk of clinical
pregnancy loss
Analysis of an Alanine/Arginine Mixture by Using TLC/FTIR Technique
We applied TLC/FTIR coupled with mapping technique to analyze an alanine/arginine mixture. Narrow band TLC plates prepared by using AgI as a stationary phase were used to separate alanine and arginine. The distribution of alanine and arginine spots was manifested by a 3D chromatogram. Alanine and arginine can be successfully separated by the narrow band TLC plate. In addition, the FTIR spectra of the separated alanine and arginine spots on the narrow band TLC plate are roughly the same as the corresponding reference IR spectra
Occurrence and Maternal Transfer of Chlorinated Bisphenol A and Nonylphenol in Pregnant Women and Their Matching Embryos
Prenatal
exposure has recently raised concerns over the health
risks of endocrine disruptors; however, little is known about their
extent and the mechanisms of maternal transfer in the embryo stage.
In this study, bisphenol A (BPA), nonylphenol (NP), and their six
chlorinated derivatives were quantified in decidua samples from 25
pregnant women and their matching embryos, which were collected as
chorionic villi samples. Monochloro-BPA (MCBPA), dichloro-BPA (DCBPA),
monochloro-NP (MCNP), and dichloro-NP (DCNP) were detected in over
70% of the decidua or chorionic villi samples, while BPA, NP, trichloro-BPA
(TCBPA), and tetrachloro-BPA (TeCBPA) were detected in less than half.
The geometric mean (GM) concentrations of MCBPA, DCBPA, NP, MCNP,
and DCNP in chorionic villi samples were 0.13, 0.17, 5.33, 4.52, and
2.44 ng/g dw, respectively, higher than those in maternal decidua
samples, which were 0.10, 0.12, 3.27, 1.85, and 0.74 ng/g dw, respectively,
while the GM concentration of BPA was lower in chorionic villi samples
(0.09 ng/g dw) than in maternal decidua (0.10 ng/g dw). The ratios
of the average lipid-normalized concentrations of chemicals in chorionic
villi to those in maternal decidua (EMR) were calculated to be 1.53
for MCNP and 2.38 for DCNP, while those of BPA, MCBPA, DCBPA, and
NP were lower than 1 (0.39–0.97). Such obvious difference in
maternal transfer is probably due to their different affinities to
plasma proteins, as exemplified by the correlation between EMR and
the binding affinities to T4 transport proteins (TTR). This is the
first report on the occurrence and maternal transfer of chlorinated
derivatives of BPA and NP in human embryos and decidua