9 research outputs found
Obesity and Cardiometabolic Risk Factors: From Childhood to Adulthood
Obesity has become a major epidemic in the 21st century. It increases the risk of dyslipidemia, hypertension, and type 2 diabetes, which are known cardiometabolic risk factors and components of the metabolic syndrome. Although overt cardiovascular (CV) diseases such as stroke or myocardial infarction are the domain of adulthood, it is evident that the CV continuum begins very early in life. Recognition of risk factors and early stages of CV damage, at a time when these processes are still reversible, and the development of prevention strategies are major pillars in reducing CV morbidity and mortality in the general population. In this review, we will discuss the role of well-known but also novel risk factors linking obesity and increased CV risk from prenatal age to adulthood, including the role of perinatal factors, diet, nutrigenomics, and nutri-epigenetics, hyperuricemia, dyslipidemia, hypertension, and cardiorespiratory fitness. The importance of 'tracking' of these risk factors on adult CV health is highlighted and the economic impact of childhood obesity as well as preventive strategies are discussed
Psychosocial and environmental risk factors of obesity and hypertension in children and adolescents—a literature overview
Childhood obesity has become a worldwide epidemic in the 21st century. Its treatment is challenging and often ineffective, among others due to complex, often not obvious causes. Awareness of the existence and meaning of psychosocial and environmental risk factors seems to be an essential element in the prevention and treatment of obesity and its complications, especially arterial hypertension. In this review, we will discuss the role of that risk factors linking obesity and increased cardiovascular disorders including the role of nutritional factors (including the role of unhealthy diet, inadequate hydration), unhealthy behaviors (e.g. smoking, alcohol and drugs, sedentary behavior, low physical activity, disrupted circadian rhythms, sleep disorders, screen exposure), unfavorable social factors (such as dysfunctional family, bullying, chronic stress, mood disorders, depression, urbanization, noise, and environmental pollution), and finally differences in cardiovascular risk in girls and boy
Mechanism of Benzylic Hydroxylation by 4‑Hydroxymandelate Synthase. A Computational Study
Hydroxymandelate synthase (HMS) and 4-hydroxyphenylpyruvate
dioxygenase
(HPPD) are highly related enzymes using the same substrates but catalyzing
hydroxylation reactions yielding different products. The first steps
of the HMS and HPPD catalytic reactions are believed to proceed in
the same way and lead to an Fe(IV)O–hydroxyphenylacetate
(HPA) intermediate. Further down the catalytic cycles, HMS uses Fe(IV)O
to perform hydroxylation of the benzylic carbon, whereas in HPPD,
the reactive oxoferryl intermediate attacks the aromatic ring of HPA.
This study focuses on this part of the HMS catalytic cycle that starts
from the oxoferryl intermediate and aims to identify interactions
within the active site that are responsible for enzyme specificity.
To this end, a HMS–Fe(IV)O–HPA complex was modeled
with molecular dynamics simulations. On the basis of the molecular
dynamics-equilibrated structure, an active site model suitable for
quantum chemical investigations was constructed and used for density
functional theory (B3LYP) calculations of the mechanism of the native
reaction of HMS, i.e., benzylic hydroxylation, and the alternative
electrophilic attack on the ring, which is a step of the HPPD catalytic
cycle. The most important result of this study is the finding that
the conformation of the Ser201 side chain in the second coordination
shell has a key role in directing the reaction of Fe(IV)O
into either the HMS or the HPPD channel
Mechanism of Benzylic Hydroxylation by 4‑Hydroxymandelate Synthase. A Computational Study
Hydroxymandelate synthase (HMS) and 4-hydroxyphenylpyruvate
dioxygenase
(HPPD) are highly related enzymes using the same substrates but catalyzing
hydroxylation reactions yielding different products. The first steps
of the HMS and HPPD catalytic reactions are believed to proceed in
the same way and lead to an Fe(IV)O–hydroxyphenylacetate
(HPA) intermediate. Further down the catalytic cycles, HMS uses Fe(IV)O
to perform hydroxylation of the benzylic carbon, whereas in HPPD,
the reactive oxoferryl intermediate attacks the aromatic ring of HPA.
This study focuses on this part of the HMS catalytic cycle that starts
from the oxoferryl intermediate and aims to identify interactions
within the active site that are responsible for enzyme specificity.
To this end, a HMS–Fe(IV)O–HPA complex was modeled
with molecular dynamics simulations. On the basis of the molecular
dynamics-equilibrated structure, an active site model suitable for
quantum chemical investigations was constructed and used for density
functional theory (B3LYP) calculations of the mechanism of the native
reaction of HMS, i.e., benzylic hydroxylation, and the alternative
electrophilic attack on the ring, which is a step of the HPPD catalytic
cycle. The most important result of this study is the finding that
the conformation of the Ser201 side chain in the second coordination
shell has a key role in directing the reaction of Fe(IV)O
into either the HMS or the HPPD channel
Role of Substrate Positioning in the Catalytic Reaction of 4‑Hydroxyphenylpyruvate DioxygenaseA QM/MM Study
Ring
hydroxylation and coupled rearrangement reactions catalyzed
by 4-hydroxyphenylpyruvate dioxygenase were studied with
the QM/MM method ONIOM(B3LYP:AMBER). For electrophilic attack of the
ferryl species on the aromatic ring, five channels were considered:
attacks on the three ring atoms closest to the oxo ligand (C1, C2,
C6) and insertion of oxygen across two bonds formed by them (C1–C2,
C1–C6). For the subsequent migration of the carboxymethyl substituent,
two possible directions were tested (C1→C2, C1→C6),
and two different mechanisms were sought (stepwise radical, single-step
heterolytic). In addition, formation of an epoxide (side)product and
benzylic hydroxylation, as catalyzed by the closely related hydroxymandelate
synthase, were investigated. From the computed reaction free energy
profiles it follows that the most likely mechanism of 4-hydroxyphenylpyruvate
dioxygenase involves electrophilic attack on the C1 carbon of the
ring and subsequent single-step heterolytic migration of the substituent.
Computed values of the kinetic isotope effect for this step are inverse,
consistent with available experimental data. Electronic structure
arguments for the preferred mechanism of attack on the ring are also
presented
Dithizone Modified Gold Nanoparticles Films for Potentiometric Sensing
For the first time, application of a membrane composed
of gold nanoparticles decorated with complexing ligand for potentiometric
sensing is shown. Gold nanoparticles drop cast from a solution form
a porous structure on a substrate electrode surface. Sample cations
can penetrate the gold nanoparticles layer and interact with ligand
acting as a charged ionophore, resulting in Nernstian potentiometric
responses. Anchoring of complexing ligand on the gold surface abolishes
the necessity of ionophore application. Moreover, it opens the possibility
of preparation of potentiometric sensors using chelators of significantly
different selectivity patterns further enhanced by the absence of
polymeric membrane matrix. This was clearly seen, for example, for
gold nanoparticles stabilizing the applied ligand–dithizone–thiol
conformation leading to a high potentiometric selectivity toward copper
ions, much higher than that of ionophores typically used to induce
selectivity for polymeric ion-selective membranes
Spin-Resolved Magneto-Tunneling and Giant Anisotropic g-Factor in Broken Gap InAs-GaSb Core-Shell Nanowires
: We experimentally and computationally investigate the magneto-conductance across the radial heterojunction of InAs-GaSb core-shell nanowires under a magnetic field, B, up to 30 T and at temperatures in the range 4.2-200 K. The observed double-peak negative differential conductance markedly blue-shifts with increasing B. The doublet accounts for spin-polarized currents through the Zeeman split channels of the InAs (GaSb) conduction (valence) band and exhibits strong anisotropy with respect to B orientation and marked temperature dependence. Envelope function approximation and a semiclassical (WKB) approach allow to compute the magnetic quantum states of InAs and GaSb sections of the nanowire and to estimate the B-dependent tunneling current across the broken-gap interface. Disentangling different magneto-transport channels and a thermally activated valence-to-valence band transport current, we extract the g-factor from the spin-up and spin-down dI/dV branch dispersion, revealing a giant, strongly anisotropic g-factor in excess of 60 (100) for the radial (tilted) field configurations
The Gallium solar neutrino experiment at Gran Sasso
We present here the status of the radiochemical Gallex experiment in the underground Laboratori Nazionali del Gran Sasso. This experiment will contribute to probe the theory of stellar structure and neutrino masses using 30 tons of natural gallium to detect pp-solar neutrinos. The first full scale run is expected in june 1990