12 research outputs found
Determinants of Serum Polybrominated Diphenyl Ether (PBDE) Levels among Pregnant Women in the CHAMACOS Cohort
Excretion Profiles and Half-Lives of Ten Urinary Polycyclic Aromatic Hydrocarbon Metabolites after Dietary Exposure
Human exposure to polycyclic aromatic hydrocarbons (PAHs)
can be
assessed by biomonitoring of their urinary monohydroxylated metabolites
(OH-PAHs). Limited information exists on the human pharmacokinetics
of OH-PAHs. This study aimed to investigate the excretion half-life
of 1-hydroxypyrene (1-PYR), the most used biomarker for PAH exposure,
and 9 other OH-PAHs following a dietary exposure in 9 nonsmoking volunteers
with no occupational exposure to PAHs. Each person avoided food with
known high PAH-content during the study period, except for a high
PAH-containing lunch (barbecued chicken) on the first day. Individual
urine samples (<i>n</i> = 217) were collected from 15 h
before to 60 h following the dietary exposure. Levels of all OH-PAHs
in all subjects increased rapidly by 9–141-fold after the exposure,
followed by a decrease consistent with first-order kinetics, and returned
to background levels 24–48 h after the exposure. The average
time to reach maximal concentration ranged from 3.1 h (1-naphthol)
to 5.5 h (1-PYR). Creatinine-adjusted urine concentrations for each
metabolite were analyzed using a nonlinear mixed effects model including
a term to estimate background exposure. The background-adjusted half-life
estimate was 3.9 h for 1-PYR and ranged 2.5–6.1 h for the other
9 OH-PAHs, which in general, were shorter than those previously reported.
The maximum concentrations after barbecued chicken consumption were
comparable to the levels found in reported occupational settings with
known high PAH exposures. It is essential to consider the relatively
short half-life, the timing of samples relative to exposures, and
the effect of diet when conducting PAH exposure biomonitoring studies
Polybrominated Diphenyl Ethers, 2,2′,4,4′,5,5′-Hexachlorobiphenyl (PCB-153), and <i>p</i>,<i>p</i>′‑Dichlorodiphenyldichloroethylene (<i>p</i>,<i>p</i>′‑DDE) Concentrations in Sera Collected in 2009 from Texas Children
Polybrominated diphenyl ethers (PBDEs),
polychlorinated biphenyls
(PCBs) and <i>p</i>,<i>p</i>′-dichlorodiphenyldichloroethylene
(<i>p</i>,<i>p</i>′-DDE) have been measured
in surplus serum collected in 2009 from a convenience sample of 300
Texas children (boys and girls) in the birth to 13 years of age range.
Serum concentrations of traditional persistent organic pollutants
such as 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB-153)
and <i>p</i>,<i>p</i>′-DDE did not change
consistently with age. By contrast, serum concentrations of tetra-,
penta-, and hexa-BDEs were lowest in the youngest children (birth
to two year old) and increased 3.0 to 7.9 times, depending on the
analyte, for children in the >4 to 6 years of age group. From the
apex concentration to the 10 to 13 years of age group, concentrations
decreased significantly except for 2,2′,4,4′,5,5′-hexabromodiphenyl
ether (PBDE-153), which also had a longer apex concentration of >4
to 8 years of age. This concentration trend for PBDE-153 is most likely
due to a longer half-life of PBDE-153 than of other PBDE congeners.
The observed PBDEs concentration patterns by age may be related, at
least in part, to ingestion of residential dust containing PBDEs through
hand-to-mouth behavior among toddlers, preschoolers, and kindergarteners.
Further studies to characterize young children’s exposure to
PBDEs are warranted and, in particular, to determine the lifestyle
factors that may contribute to such exposures
Proton Coupled Electron Transfer and Redox-Active Tyrosine Z in the Photosynthetic Oxygen-Evolving Complex
Bidirectional and unidirectional PCET in a molecular model of a cobalt-based oxygen-evolving catalyst
The oxidation of water to molecular oxygen is a kinetically demanding reaction that requires efficient coupling of proton and electron transfer. The key proton-coupled electron transfer (PCET) event in water oxidation mediated by a cobalt-phosphate-based heterogeneous catalyst is the one-electron, one-proton conversion of Co(III)-OH to Co(IV)-O. We now isolate the kinetics of this PCET step in a molecular Co(4)O(4) cubane model compound. Detailed electrochemical, stopped-flow, and NMR studies of the CoIII-OH to Co(IV)-O reaction reveal distinct mechanisms for the unidirectional PCET self-exchange reaction and the corresponding bidirectional PCET. A stepwise mechanism, with rate-limiting electron transfer is observed for the bidirectional PCET at an electrode surface and in solution, whereas a concerted proton electron transfer displaying a moderate KIE (4.3 +/- 0.2), is observed for the unidirectional self-exchange reaction
Chromosome 19 Annotations with Disease Speciation: A First Report from the Global Research Consortium
A first research development progress report of the Chromosome
19 Consortium with members from Sweden, Norway, Spain, United States,
China and India, a part of the Chromosome-centric Human Proteome Project
(C-HPP) global initiative, is presented (http://www.c-hpp.org). From the chromosome 19 peptide-targeted library constituting 6159
peptides, a pilot study was conducted using a subset with 125 isotope-labeled
peptides. We applied an annotation strategy with triple quadrupole,
ESI-Qtrap, and MALDI mass spectrometry platforms, comparing the quality
of data within and in between these instrumental set-ups. LC–MS
conditions were outlined by multiplex assay developments, followed
by MRM assay developments. SRM was applied to biobank samples, quantifying
kallikrein 3 (prostate specific antigen) in plasma from prostate cancer
patients. The antibody production has been initiated for more than
1200 genes from the entire chromosome 19, and the progress developments
are presented. We developed a dedicated transcript microarray to serve
as the mRNA identifier by screening cancer cell lines. NAPPA protein
arrays were built to align with the transcript data with the Chromosome
19 NAPPA chip, dedicated to 90 proteins, as the first development
delivery. We have introduced an IT-infrastructure utilizing a LIMS
system that serves as the key interface for the research teams to
share and explore data generated within the project. The cross-site
data repository will form the basis for sample processing, including
biological samples as well as patient samples from national Biobanks
Chromosome 19 Annotations with Disease Speciation: A First Report from the Global Research Consortium
A first research development progress report of the Chromosome
19 Consortium with members from Sweden, Norway, Spain, United States,
China and India, a part of the Chromosome-centric Human Proteome Project
(C-HPP) global initiative, is presented (http://www.c-hpp.org). From the chromosome 19 peptide-targeted library constituting 6159
peptides, a pilot study was conducted using a subset with 125 isotope-labeled
peptides. We applied an annotation strategy with triple quadrupole,
ESI-Qtrap, and MALDI mass spectrometry platforms, comparing the quality
of data within and in between these instrumental set-ups. LC–MS
conditions were outlined by multiplex assay developments, followed
by MRM assay developments. SRM was applied to biobank samples, quantifying
kallikrein 3 (prostate specific antigen) in plasma from prostate cancer
patients. The antibody production has been initiated for more than
1200 genes from the entire chromosome 19, and the progress developments
are presented. We developed a dedicated transcript microarray to serve
as the mRNA identifier by screening cancer cell lines. NAPPA protein
arrays were built to align with the transcript data with the Chromosome
19 NAPPA chip, dedicated to 90 proteins, as the first development
delivery. We have introduced an IT-infrastructure utilizing a LIMS
system that serves as the key interface for the research teams to
share and explore data generated within the project. The cross-site
data repository will form the basis for sample processing, including
biological samples as well as patient samples from national Biobanks
Chromosome 19 Annotations with Disease Speciation: A First Report from the Global Research Consortium
A first research development progress report of the Chromosome
19 Consortium with members from Sweden, Norway, Spain, United States,
China and India, a part of the Chromosome-centric Human Proteome Project
(C-HPP) global initiative, is presented (http://www.c-hpp.org). From the chromosome 19 peptide-targeted library constituting 6159
peptides, a pilot study was conducted using a subset with 125 isotope-labeled
peptides. We applied an annotation strategy with triple quadrupole,
ESI-Qtrap, and MALDI mass spectrometry platforms, comparing the quality
of data within and in between these instrumental set-ups. LC–MS
conditions were outlined by multiplex assay developments, followed
by MRM assay developments. SRM was applied to biobank samples, quantifying
kallikrein 3 (prostate specific antigen) in plasma from prostate cancer
patients. The antibody production has been initiated for more than
1200 genes from the entire chromosome 19, and the progress developments
are presented. We developed a dedicated transcript microarray to serve
as the mRNA identifier by screening cancer cell lines. NAPPA protein
arrays were built to align with the transcript data with the Chromosome
19 NAPPA chip, dedicated to 90 proteins, as the first development
delivery. We have introduced an IT-infrastructure utilizing a LIMS
system that serves as the key interface for the research teams to
share and explore data generated within the project. The cross-site
data repository will form the basis for sample processing, including
biological samples as well as patient samples from national Biobanks
Chromosome 19 Annotations with Disease Speciation: A First Report from the Global Research Consortium
A first research development progress report of the Chromosome
19 Consortium with members from Sweden, Norway, Spain, United States,
China and India, a part of the Chromosome-centric Human Proteome Project
(C-HPP) global initiative, is presented (http://www.c-hpp.org). From the chromosome 19 peptide-targeted library constituting 6159
peptides, a pilot study was conducted using a subset with 125 isotope-labeled
peptides. We applied an annotation strategy with triple quadrupole,
ESI-Qtrap, and MALDI mass spectrometry platforms, comparing the quality
of data within and in between these instrumental set-ups. LC–MS
conditions were outlined by multiplex assay developments, followed
by MRM assay developments. SRM was applied to biobank samples, quantifying
kallikrein 3 (prostate specific antigen) in plasma from prostate cancer
patients. The antibody production has been initiated for more than
1200 genes from the entire chromosome 19, and the progress developments
are presented. We developed a dedicated transcript microarray to serve
as the mRNA identifier by screening cancer cell lines. NAPPA protein
arrays were built to align with the transcript data with the Chromosome
19 NAPPA chip, dedicated to 90 proteins, as the first development
delivery. We have introduced an IT-infrastructure utilizing a LIMS
system that serves as the key interface for the research teams to
share and explore data generated within the project. The cross-site
data repository will form the basis for sample processing, including
biological samples as well as patient samples from national Biobanks