scholarly journals Monitoring of Peroxide in Gamma Irradiated EVA Multilayer Film Using Methionine Probe

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3024
Author(s):  
Nina Girard-Perier ◽  
Magalie Claeys-Bruno ◽  
Sylvain R. A. Marque ◽  
Nathalie Dupuy ◽  
Fanny Gaston ◽  
...  
Keyword(s):  
Design Of Experiments ◽  
Formation Rate ◽  
Methionine Sulfoxide ◽  
Reactive Species ◽  
Mechanisms Of Formation ◽  
Radiation Induced ◽  
Single Use ◽  
Oxidation Of Methionine ◽  
Gamma Irradiated ◽  
The Impact

In this study, the oxidation of methionine is used as a proxy to model the gamma radiation-induced changes in single-use bags; these changes lead to the formation of acids, radicals, and hydroperoxides. The mechanisms of formation of these reactive species and of methionine oxidation are discussed. With the help of reaction kinetics, the optimal conditions for the use of these single-use bags minimizing the impact of radical chemistry are highlighted. Biopharmaceutical bags gamma irradiated from 0 kGy to 260 kGy and aged from 0 to 36 months were filled with a methionine solution to follow the oxidation of the methionine. The methionine sulfoxide was measured with HPLC after different storage times (0, 3, 10, 14, 17, and 21 days). Three main results were analyzed through a design of experiments: the oxidative induction time, the methionine sulfoxide formation rate, and the maximum methionine sulfoxide concentration detected. A key aspect of the study is that it highlights that methionine is oxidized not necessarily directly by hydro(gen) peroxide but throughperacid, and likely peracetic acid. The answers to the design of experiments were considered to obtain the desirability domain for the optimization of the conditions of use for the single-use bags limiting the oxidation of methionine as well as the release of reactive species thereof.

scholarly journals Impact of Pharmaceutical Prophylaxis on Radiation-Induced Liver Disease Following Radioembolization

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1992
Author(s):  
Max Seidensticker ◽  
Matthias Philipp Fabritius ◽  
Jannik Beller ◽  
Ricarda Seidensticker ◽  
Andrei Todica ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Liver Disease ◽  
Positive Impact ◽  
Metastatic Breast ◽  
Normal Liver ◽  
Liver Parenchyma ◽  
Breast Cancer Patients ◽  
Radiation Induced ◽  
The Impact

Background: Radioembolization (RE) with yttrium-90 (90Y) resin microspheres yields heterogeneous response rates in with primary or secondary liver cancer. Radiation-induced liver disease (RILD) is a potentially life-threatening complication with higher prevalence in cirrhotics or patients exposed to previous chemotherapies. Advances in RILD prevention may help increasing tolerable radiation doses to improve patient outcomes. This study aimed to evaluate the impact of post-therapeutic RILD-prophylaxis in a cohort of intensely pretreated liver metastatic breast cancer patients; Methods: Ninety-three patients with liver metastases of breast cancer received RE between 2007 and 2016. All Patients received RILD prophylaxis for 8 weeks post-RE. From January 2014, RILD prophylaxis was changed from ursodeoxycholic acid (UDCA) and prednisolone (standard prophylaxis [SP]; n = 59) to pentoxifylline (PTX), UDCA and low-dose low molecular weight heparin (LMWH) (modified prophylaxis (MP); n = 34). The primary endpoint was toxicity including symptoms of RILD; Results: Dose exposure of normal liver parenchyma was higher in the modified vs. standard prophylaxis group (47.2 Gy (17.8–86.8) vs. 40.2 Gy (12.5–83.5), p = 0.017). All grade RILD events (mild: bilirubin ≥ 21 µmol/L (but <30 μmol/L); severe: (bilirubin ≥ 30 µmol/L and ascites)) were observed more frequently in the SP group than in the MP group, albeit without significance (7/59 vs. 1/34; p = 0.140). Severe RILD occurred in the SP group only (n = 2; p > 0.1). ALBI grade increased in 16.7% patients in the MP and in 27.1% patients in the SP group, respectively (group difference not significant); Conclusions: At established dose levels, mild or severe RILD events proved rare in our cohort. RILD prophylaxis with PTX, UDCA and LMWH appears to have an independent positive impact on OS in patients with metastatic breast cancer and may reduce the frequency and severity of RILD. Results of this study as well as pathophysiological considerations warrant further investigations of RILD prophylaxis presumably targeting combinations of anticoagulation (MP) and antiinflammation (SP) to increase dose prescriptions in radioembolization.

scholarly journals Peptide-Bound Methionine Sulfoxide (MetO) Levels and MsrB2 Abundance Are Differentially Regulated during the Desiccation Phase in Contrasted Acer Seeds

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 391 ◽  
Author(s):  
Natalia Wojciechowska ◽  
Shirin Alipour ◽  
Ewelina Stolarska ◽  
Karolina Bilska ◽  
Pascal Rey ◽  
...  
Keyword(s):  
Desiccation Tolerance ◽  
Methionine Sulfoxide ◽  
Redox Status ◽  
Embryonic Axes ◽  
Seed Desiccation ◽  
Methionine Sulfoxide Reductases ◽  
Norway Maple ◽  
Orthodox Seeds ◽  
Oxidation Of Methionine ◽  
Reduced Forms

Norway maple and sycamore produce desiccation-tolerant (orthodox) and desiccation-sensitive (recalcitrant) seeds, respectively. Drying affects reduction and oxidation (redox) status in seeds. Oxidation of methionine to methionine sulfoxide (MetO) and reduction via methionine sulfoxide reductases (Msrs) have never been investigated in relation to seed desiccation tolerance. MetO levels and the abundance of Msrs were investigated in relation to levels of reactive oxygen species (ROS) such as hydrogen peroxide, superoxide anion radical and hydroxyl radical (•OH), and the levels of ascorbate and glutathione redox couples in gradually dried seeds. Peptide-bound MetO levels were positively correlated with ROS concentrations in the orthodox seeds. In particular, •OH affected MetO levels as well as the abundance of MsrB2 solely in the embryonic axes of Norway maple seeds. In this species, MsrB2 was present in oxidized and reduced forms, and the latter was favored by reduced glutathione and ascorbic acid. In contrast, sycamore seeds accumulated higher ROS levels. Additionally, MsrB2 was oxidized in sycamore throughout dehydration. In this context, the three elements •OH level, MetO content and MsrB2 abundance, linked together uniquely to Norway maple seeds, might be considered important players of the redox network associated with desiccation tolerance.

scholarly journals Modelling H2 and its effects on star formation using a joint implementation of gadget-3 and KROME

2021 ◽  
Vol 504 (2) ◽  
pp. 2325-2345
Author(s):  
Emanuel Sillero ◽  
Patricia B Tissera ◽  
Diego G Lambas ◽  
Stefano Bovino ◽  
Dominik R Schleicher ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Physical Parameters ◽  
Density Profiles ◽  
Star Forming ◽  
Chemical Enrichment ◽  
Numerical Resolution ◽  
Stellar Radiation ◽  
Wide Range ◽  
The Impact

ABSTRACT We present p-gadget3-k, an updated version of gadget-3, that incorporates the chemistry package krome. p-gadget3-k follows the hydrodynamical and chemical evolution of cosmic structures, incorporating the chemistry and cooling of H2 and metal cooling in non-equilibrium. We performed different runs of the same ICs to assess the impact of various physical parameters and prescriptions, namely gas metallicity, molecular hydrogen formation on dust, star formation recipes including or not H2 dependence, and the effects of numerical resolution. We find that the characteristics of the simulated systems, both globally and at kpc-scales, are in good agreement with several observable properties of molecular gas in star-forming galaxies. The surface density profiles of star formation rate (SFR) and H2 are found to vary with the clumping factor and resolution. In agreement with previous results, the chemical enrichment of the gas component is found to be a key ingredient to model the formation and distribution of H2 as a function of gas density and temperature. A star formation algorithm that takes into account the H2 fraction together with a treatment for the local stellar radiation field improves the agreement with observed H2 abundances over a wide range of gas densities and with the molecular Kennicutt–Schmidt law, implying a more realistic modelling of the star formation process.

scholarly journals Thermal processing contaminants in foodstuffs and potential  strategies of control

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S1-S10 ◽  
Author(s):  
A. Studer ◽  
I. Blank ◽  
R. H Stadler
Keyword(s):  
Health Risks ◽  
Food Service ◽  
Food Product ◽  
Heterocyclic Aromatic Amines ◽  
Heat Processing ◽  
Food Container ◽  
Mechanisms Of Formation ◽  
Polycyclic Aromatic ◽  
Us Fda ◽  
The Impact

Over the past decades, researchers from academia, industry, and National authorities and enforcement laboratories, have gained increasing insight in understanding the presence, formation and potential risk to public health posed by the compounds formed during the domestic cooking and heat-processing of different foods. Compounds already intensively studied are the heterocyclic aromatic amines, polycyclic aromatic hydrocarbons, and chloropropanols. Concrete measures have been introduced by the food industry to control certain contaminants, exemplified by the introduction of enzymatic hydrolysis of plant proteins or over-neutralization to reduce concentrations of chloropropanols in savoury flavours. The recent discovery of acrylamide in cooked foods has raised much concern, and sparked intensive scientific studies into the occurrence, analysis, exposure, mechanisms of formation, possible measures of control, and toxicology of the compound. However, since acrylamide formation is directly linked to the desired Maillard reaction that generates important flavour and aroma compounds – as well as chemicals with potentially beneficial health effects – any measures taken must assess the impact on overall quality and consumer acceptance of the food product. In addition, mitigation must be devised in such a way as not to increase the risks for other possibly more severe short and medium to long-term health risks. In this context, understanding the impact of changes in processing on the safety of foods will be of paramount importance. In May 2004 the US FDA published findings of trace levels of furan in different foods, corroborating older data and raising some concerns, albeit without reference to any health risks. Particularly canned and jarred foods that are subject to thermal treatment are apparently affected, as the volatile furan is essentially “trapped” in the food container. Analogous to the acrylamide concern, there is a paucity of knowledge in all scientific domains, i.e. exposure, methods of analysis, mechanisms of formation, toxicology. Finally, a concern that needs to be addressed is the lack of knowledge about the effects of final preparation in food service and domestic situations on the formation of processing contaminants. In essence, consumers should follow sound dietary and health advice by choosing diets based on balance, variety and moderation.

scholarly journals l-Pyroglutamate Spontaneously Formed from l-Glutamate Inhibits Growth of the Hyperthermophilic Archaeon Sulfolobus solfataricus

2001 ◽  
Vol 67 (8) ◽  
pp. 3650-3654 ◽  
Author(s):  
Chan B. Park ◽  
Sun Bok Lee ◽  
Dewey D. Y. Ryu
Keyword(s):  
Cell Growth ◽  
Growth Inhibition ◽  
Yeast Extract ◽  
Formation Rate ◽  
Sulfolobus Solfataricus ◽  
Methionine Sulfoxide ◽  
Inhibitory Effect ◽  
Culture Conditions ◽  
Culture Broth ◽  
Cell Growth Inhibition

ABSTRACT Identification of physiological and environmental factors that limit efficient growth of hyperthermophiles is important for practical application of these organisms to the production of useful enzymes or metabolites. During fed-batch cultivation of Sulfolobus solfataricus in medium containing l-glutamate, we observed formation of l-pyroglutamic acid (PGA). PGA formed spontaneously from l-glutamate under culture conditions (78°C and pH 3.0), and the PGA formation rate was much higher at an acidic or alkaline pH than at neutral pH. It was also found that PGA is a potent inhibitor of S. solfataricus growth. The cell growth rate was reduced by one-half by the presence of 5.1 mM PGA, and no growth was observed in the presence of 15.5 mM PGA. On the other hand, the inhibitory effect of PGA on cell growth was alleviated by addition of l-glutamate or l-aspartate to the medium. PGA was also produced from the l-glutamate in yeast extract; the PGA content increased to 8.5% (wt/wt) after 80 h of incubation of a yeast extract solution at 78°C and pH 3.0. In medium supplemented with yeast extract, cell growth was optimal in the presence of 3.0 g of yeast extract per liter, and higher yeast extract concentrations resulted in reduced cell yields. The extents of cell growth inhibition at yeast extract concentrations above the optimal concentration were correlated with the PGA concentration in the culture broth. Although other structural analogues ofl-glutamate, such as l-methionine sulfoxide, glutaric acid, succinic acid, and l-glutamic acid γ-methyl ester, also inhibited the growth of S. solfataricus, the greatest cell growth inhibition was observed with PGA. We also observed that unlike other glutamate analogues,N-acetyl-l-glutamate enhanced the growth of S. solfataricus. This compound was stable under cell culture conditions, and replacement of l-glutamate with N-acetyl-l-glutamate in the medium resulted in increased cell density.

Sign in / Sign up

Export Citation Format

Share Document