22 research outputs found
The 125Te Chemical Shift of Diphenyl Ditelluride: Chasing Conformers over a Flat Energy Surface
The interest in diphenyl ditelluride (Ph2Te2) is related to its strict analogy to diphenyl
diselenide (Ph2Se2), whose capacity to reduce organic peroxides is largely exploited in catalysis and
green chemistry. Since the latter is also a promising candidate as an antioxidant drug and mimic of the
ubiquitous enzyme glutathione peroxidase (GPx), the use of organotellurides in medicinal chemistry
is gaining importance, despite the fact that tellurium has no recognized biological role and its toxicity
must be cautiously pondered. Both Ph2Se2 and Ph2Te2 exhibit significant conformational freedom
due to the softness of the inter-chalcogen and carbon\u2013chalcogen bonds, preventing the existence of a
unique structure in solution. Therefore, the accurate calculation of the NMR chemical shifts of these
flexible molecules is not trivial. In this study, a detailed structural analysis of Ph2Te2 is carried out
using a computational approach combining classical molecular dynamics and relativistic density
functional theory methods. The goal is to establish how structural changes affect the electronic
structure of diphenyl ditelluride, particularly the 125Te chemical shift
Psychiatric Disorders and Oxidative Injury: Antioxidant Effects of Zolpidem Therapy disclosed In Silico
Zolpidem (N,N-Dimethyl-2-[6-methyl-2-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]acetamide) is a well-known drug for the treatment of sleeping disorders. Recent literature reports on positive effects of zolpidem therapy on improving renal damage after cisplatin and on reducing akinesia without sleep induction. This has been ascribed to the antioxidant and neuroprotective capacity of this molecule, and tentatively explained according to a generic structural similarity between zolpidem and melatonin. In this work, we investigate in silico the antioxidant potential of zolpidem as scavenger of five ROSs, acting via hydrogen atom transfer (HAT) mechanism; computational methodologies based on density functional theory are employed. For completeness, the analysis is extended to six metabolites. Thermodynamic and kinetic results disclose that indeed zolpidem is an efficient radical scavenger, similarly to melatonin and Trolox, supporting the biomedical evidence that the antioxidant potential of zolpidem therapy may have a beneficial effect against oxidative injury, which is emerging as an important etiopathogenesis in numerous severe diseases, including psychiatric disorders
Monitoring of hadrontherapy treatments by means of charged particle detection
The interaction of the incoming beam radiation with the patient body in hadrontherapy
treatments produces secondary charged and neutral particles, whose detection can be
used for monitoring purposes and to perform an on-line check of beam particle range. In
the context of ion-therapy with active scanning, charged particles are potentially attractive
since they can be easily tracked with a high efficiency, in presence of a relatively low
background contamination. In order to verify the possibility of exploiting this approach
for in-beam monitoring in ion-therapy, and to guide the design of specific detectors, both
simulations and experimental tests are being performed with ion beams impinging on
simple homogeneous tissue-like targets (PMMA). From these studies, a resolution of the
order of few millimeters on the single track has been proven to be sufficient to exploit
charged particle tracking for monitoring purposes, preserving the precision achievable
on longitudinal shape. The results obtained so far show that the measurement of charged
particles can be successfully implemented in a technology capable of monitoring both
the dose profile and the position of the Bragg peak inside the target and finally lead to
the design of a novel profile detector. Crucial aspects to be considered are the detector
positioning, to be optimized in order to maximize the available statistics, and the capability
of accounting for the multiple scattering interactions undergone by the charged
fragments along their exit path from the patient body. The experimental results collected
up to now are also valuable for the validation of Monte Carlo simulation software tools
and their implementation in Treatment Planning Software packages
Charged particle's flux measurement from PMMA irradiated by 80 MeV/u carbon ion beam
Hadrontherapy is an emerging technique in cancer therapy that uses beams of
charged particles. To meet the improved capability of hadrontherapy in matching
the dose release with the cancer position, new dose monitoring techniques need
to be developed and introduced into clinical use. The measurement of the fluxes
of the secondary particles produced by the hadron beam is of fundamental
importance in the design of any dose monitoring device and is eagerly needed to
tune Monte Carlo simulations. We report the measurements done with charged
secondary particles produced from the interaction of a 80 MeV/u fully stripped
carbon ion beam at the INFN Laboratori Nazionali del Sud, Catania, with a
Poly-methyl methacrylate target. Charged secondary particles, produced at
90 with respect to the beam axis, have been tracked with a drift
chamber, while their energy and time of flight has been measured by means of a
LYSO scintillator. Secondary protons have been identified exploiting the energy
and time of flight information, and their emission region has been
reconstructed backtracking from the drift chamber to the target. Moreover a
position scan of the target indicates that the reconstructed emission region
follows the movement of the expected Bragg peak position. Exploting the
reconstruction of the emission region, an accuracy on the Bragg peak
determination in the submillimeter range has been obtained. The measured
differential production rate for protons produced with 83 MeV and emitted at 90 with respect to the beam line is: .Comment: 13 pages, 9 figure
International consensus guidelines for the diagnosis and management of food protein–induced enterocolitis syndrome: Executive summary—Workgroup Report of the Adverse Reactions to Foods Committee, American Academy of Allergy, Asthma & Immunology
Food protein-induced enterocolitis (FPIES) is a non-IgE cell- mediated food allergy that can be severe and lead to shock. Despite the potential seriousness of reactions, awareness of FPIES is low; high-quality studies providing insight into the pathophysiology, diagnosis, and management are lacking; and clinical outcomes are poorly established. This consensus document is the result of work done by an international workgroup convened through the Adverse Reactions to Foods Committee of the American Academy of Allergy, Asthma & Immunology and the International FPIES Association advocacy group. These are the first international evidence-based guidelines to improve the diagnosis and management of patients with FPIES. Research on prevalence, pathophysiology, diagnostic markers, and future treatments is necessary to improve the care of patients with FPIES. These guidelines will be updated periodically as more evidence becomes available
Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19
Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe
Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies
There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity
The 125Te Chemical Shift of Diphenyl Ditelluride: Chasing Conformers over a Flat Energy Surface
The <sup>125</sup>Te Chemical Shift of Diphenyl Ditelluride: Chasing Conformers over a Flat Energy Surface
The interest in diphenyl ditelluride (Ph2Te2) is related to its strict analogy to diphenyl diselenide (Ph2Se2), whose capacity to reduce organic peroxides is largely exploited in catalysis and green chemistry. Since the latter is also a promising candidate as an antioxidant drug and mimic of the ubiquitous enzyme glutathione peroxidase (GPx), the use of organotellurides in medicinal chemistry is gaining importance, despite the fact that tellurium has no recognized biological role and its toxicity must be cautiously pondered. Both Ph2Se2 and Ph2Te2 exhibit significant conformational freedom due to the softness of the inter-chalcogen and carbon–chalcogen bonds, preventing the existence of a unique structure in solution. Therefore, the accurate calculation of the NMR chemical shifts of these flexible molecules is not trivial. In this study, a detailed structural analysis of Ph2Te2 is carried out using a computational approach combining classical molecular dynamics and relativistic density functional theory methods. The goal is to establish how structural changes affect the electronic structure of diphenyl ditelluride, particularly the 125Te chemical shift