Cholesterol Oxidation Mechanisms

2002 ◽  
Author(s):  
Maria Teresa Rodriguez-Estrada ◽  
Giovanni Lercker
Keyword(s):  
Cholesterol Oxidation ◽  
Oxidation Mechanisms

scholarly journals Sterol auto-oxidation adversely affects human motor neuron viability and is a neuropathological feature of amyotrophic lateral sclerosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
James C. Dodge ◽  
Jinlong Yu ◽  
S. Pablo Sardi ◽  
Lamya S. Shihabuddin
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neuron ◽  
Cholesterol Homeostasis ◽  
Cholesterol Oxidation ◽  
Therapeutic Approaches ◽  
Cellular Survival ◽  
Sporadic Als ◽  
Human Motor ◽  
Als Patients ◽  
Lateral Sclerosis

AbstractAberrant cholesterol homeostasis is implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), a fatal neuromuscular disease that is due to motor neuron (MN) death. Cellular toxicity from excess cholesterol is averted when it is enzymatically oxidized to oxysterols and bile acids (BAs) to promote its removal. In contrast, the auto oxidation of excess cholesterol is often detrimental to cellular survival. Although oxidized metabolites of cholesterol are altered in the blood and CSF of ALS patients, it is unknown if increased cholesterol oxidation occurs in the SC during ALS, and if exposure to oxidized cholesterol metabolites affects human MN viability. Here, we show that in the SOD1G93A mouse model of ALS that several oxysterols, BAs and auto oxidized sterols are increased in the lumbar SC, plasma, and feces during disease. Similar changes in cholesterol oxidation were found in the cervical SC of sporadic ALS patients. Notably, auto-oxidized sterols, but not oxysterols and BAs, were toxic to iPSC derived human MNs. Thus, increased cholesterol oxidation is a manifestation of ALS and non-regulated sterol oxidation likely contributes to MN death. Developing therapeutic approaches to restore cholesterol homeostasis in the SC may lead to a treatment for ALS.

scholarly journals Effect of Dietary Hazelnut Peels on the Contents of Fatty Acids, Cholesterol, Tocopherols, and on the Shelf-Life of Ripened Ewe Cheese

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 538
Author(s):  
Vita Maria Marino ◽  
Teresa Rapisarda ◽  
Margherita Caccamo ◽  
Bernardo Valenti ◽  
Alessandro Priolo ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Dry Matter ◽  
Tocopherol Content ◽  
The Other ◽  
Cholesterol Oxidation ◽  
Cholesterol Levels ◽  
Bulk Milk ◽  
Chocolate Industry ◽  
Experimental Group ◽  
Effect Of Feeding

Hazelnut peel (HNP), a by-product from the chocolate industry, is considered to be a suitable ingredient to be included in the diet of ruminants. This study aimed to evaluate the effect of feeding dairy ewes with a diet containing HNP on ripened cheese quality, including fatty acid (FA) profile, cholesterol, and tocopherol content, as well as stability during storage under commercial conditions. In total, 10 experimental cheeses were produced with bulk milk obtained from ewes fed a commercial concentrate (C group; n = 5) or a concentrate containing 36% HNP in dry matter (HNP group; n = 5). After 40 days of aging, each cheese was sub-sampled into three slices: one was analyzed immediately (C0 and HNP0), and the other two were refrigerated and analyzed after seven days (C7 and HNP7) and 14 days (C14 and HNP14), respectively. Compared to C, HNP cheese had more than twice as many tocopherols and mono-unsaturated FA and respectively 38% and 24% less of cholesterol and saturated FA. Tocopherols and cholesterol levels remained rather stable up to 14 days of storage regardless of the experimental group, suggesting no cholesterol oxidation. Therefore, the inclusion of HNP in ewe diets could be a valid resource to produce cheese with a healthier lipid profile and higher tocopherols content.

The application of the QSSA via reaction lumping for the reduction of complex hydrocarbon oxidation mechanisms

2009 ◽  
Vol 32 (1) ◽  
pp. 543-551 ◽  
Author(s):  
Kevin J. Hughes ◽  
Mike Fairweather ◽  
John F. Griffiths ◽  
Richard Porter ◽  
Alison S. Tomlin
Keyword(s):  
Hydrocarbon Oxidation ◽  
Oxidation Mechanisms

scholarly journals Effects of Dietary Cholesterol and Its Oxidation Products on Pathological Lesions and Cholesterol and Lipid Oxidation in the Rabbit Liver

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Sun Jin Hur ◽  
Ki Chang Nam ◽  
Byungrok Min ◽  
Min Du ◽  
Kwon Il Seo ◽  
...  
Keyword(s):  
Lipid Oxidation ◽  
Dietary Cholesterol ◽  
Thiobarbituric Acid ◽  
Oxidation Products ◽  
Rabbit Liver ◽  
Cholesterol Oxidation ◽  
Liver Lesions ◽  
Thiobarbituric Acid Reactive Substances ◽  
Pathological Lesions ◽  
Very High

This study was conducted to determine the effects of dietary cholesterol (CHO) and cholesterol oxidation products (COPs) on the induction of pathological lesions in rabbit liver tissues. Liver lesions were induced only when the levels of CHO and COPs in the diet were very high. The amount of CHO measured in the liver increased when dietary CHO was increased; by comparison, dietary COPs affected liver CHO amounts to a lesser extent. The TBARS (thiobarbituric acid reactive substances) value measured for the liver samples also increased when dietary CHO and COP levels were elevated, and the TBARS value was more strongly affected by the amount of COPs in the diet than by the amount of CHO. At 6 and 12 weeks, COP levels were the highest in the group that received 1.2 g CHO + 0.8 g COPs, followed by the 0.5 g CHO + 0.5 g COPs and 1.6 g CHO + 0.4 g COPs groups; the control (0 g) group showed the lowest COP levels among all groups. In this study, we found that not only dietary CHO but also COPs were involved in hypercholesterolemia induced liver lesions when the amount of CHO and COPs was high.

Propylene Oxidation Mechanisms and Intermediates Using in Situ Soft X-ray Fluorescence Methods on the Pt(111) Surface

2000 ◽  
Vol 122 (1) ◽  
pp. 143-149 ◽  
Author(s):  
Aaron M. Gabelnick ◽  
Adam T. Capitano ◽  
Sean M. Kane ◽  
John L. Gland ◽  
Daniel A. Fischer
Keyword(s):  
Propylene Oxidation ◽  
X Ray ◽  
Fluorescence Methods ◽  
Oxidation Mechanisms

scholarly journals Kinetics Of Charge Generation During Formation Of Hf And Zr Silicate Dielectrics

2003 ◽  
Vol 765 ◽  
Author(s):  
Theodosia Gougousi ◽  
M. Jason Kelly ◽  
Gregory N. Parsons
Keyword(s):  
Photoelectron Spectroscopy ◽  
State Density ◽  
Fixed Charge ◽  
Charge Generation ◽  
Flatband Voltage ◽  
Partial Neutralization ◽  
High Dielectric ◽  
Charged Defects ◽  
Kinetics Of ◽  
Oxidation Mechanisms

AbstractUnderstanding charged defects in high dielectric constant insulators is a critical challenge for advanced devices. We have formed thin Zr and Hf silicates by oxidation of thin metal films sputtered on clean Si(100) and studied the effect of oxidation time (15 to 300s) and temperature (600 or 900°C) on the flatband voltage using capacitance vs. voltage measurements. We find that the thermal budget during oxidation and the type of oxidizing agent (slow vs. fast) affect the amount of fixed charge in the film significantly. Oxidation of 0.8nm of Zr metal on Si at 600°C in N2O for 15s results in EOT=1.2nm and a shift in the flatband voltage by ∼-0.2V indicating generation of positive fixed charge. Oxidation of similar films for 300s result in EOT=2.8nm and shift of the flatband voltage by ∼-0.95V. Hf films oxidized in N2O also show increased concentrations of fixed charge for longer oxidation times. By comparison, Si oxidized in the same environment does not show this extent of flatband voltage shift. A significantly reduced charge generation rate is observed for Hf oxidation under low O2 partial pressure. Extended oxidations (up to 1h) result in increased EOT and a slight decrease in the charged defect state density. Forming Gas Anneal (FGA) results in partial neutralization of the charge. FGA after the Al gate deposition also leads to significant decrease of the EOT (from 2.7 to 2.1nm) indicating significant reaction of the film with the gate metal. X-ray photoelectron spectroscopy for thin films indicates formation of Zr and Hf-silicates. However, for thick Hf films the low O2 oxidation process results in less silicon incorporation in the film as compared to films oxidized in N2O. Results suggest that understanding oxidation mechanisms will be important in isolating andcontrollingfixedchargeinhigh-kdielectrics.

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