Abdelouahed Khalil

Université de Sherbrooke

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Tamàs Fülöp

Université de Sherbrooke

Hicham Berrougui

Université Sultan Moulay Slimane

Anis Larbi

Singapore Immunology Network

Jacek M. Witkowski

Gdańsk Medical University

Isabelle J. Dionne

Université de Sherbrooke

M’hamed Bentourkia

Université de Sherbrooke

ÉT

Éric Turcotte

Université de Sherbrooke

Nada Zoubdane

Université de Sherbrooke

Gilles Dupuis

Université de Sherbrooke

Mounia Cherki

University of Hassan II Casablanca

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Université de Sherbrooke

149

Inserm

Health and Social Services Centre University Institute of Geriatrics of Sherbrooke

Centre Hospitalier Universitaire de Sherbrooke

Sapienza University of Rome

Karolinska Institutet

Centre National de la Recherche Scientifique

Universidad Autónoma de Madrid

University of Bologna

Universitätsklinikum Aachen

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Oxidation of Human High-Density Lipoproteins by ∙ OH and ∙ OH/O 2 ∙- Free Radicals

Radiation Research (1997)

Dominique Bonnefont–Rousselot Abdelouahed Khalil J Delattre D. Jore M Gardès-Albert

The aim of this work was to specify the mechanisms involved in the radical oxidation of human high-density lipoprotein (HDL) and to compare these mechanisms with those described previously for the oxidation of low-density lipoprotein (LDL) under the same experimental conditions (Bonnefont-Rousselot et al., Radiat, Res. 134, 271-282, 1993). The oxidation of HDL, initiated by .OH or .OH/O(.-)2 free radicals from gamma radiolysis of water, was evaluated as a function of increasing radiation dose by analyzing quantitatively the decrease of endogenous alpha-tocopherol and the formation of oxidation products (thiobarbituric acid-reactive substances and conjugated dienes). All qualitative conclusions were supported by quantitative data (radiation yields and concentrations of the oxidation markers at high radiation doses) and by the mechanisms of the kinetics, .OH free radicals in the absence of oxygen were less efficient in initiating HDL oxidation than in the presence of oxygen (action of .OH/O(.-)2 free radicals), which was in agreement with the enhancement of the action of .OH free radicals by oxygen. The remaining significant level of vitamin E in HDLs at high radiation doses in the absence of oxygen could be explained by a regeneration of vitamin E by an oxidation product that was able to reduce the alpha-tocopheroxyl radical. The yields related to the decrease in the vitamin E content of HDLs after exposure to radiation with .OH or .OH/O(.-)2 free radicals were slightly higher than those obtained previously in LDLs under similar experimental conditions. Moreover, in the presence of oxygen, .OH free radicals led to a lower formation of thiobarbituric acid-reactive substances in HDLs than in LDLs. Such discrepancies in the behavior of these two lipoprotein fractions could be related to the differences in the chemical composition of HDLs and LDLs.

Thiobarbituric acid

10.2307/3579486

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Citations (19)

Age-Related Alterations in PON1

Springer eBooks (2007)

I. Serés Tamás Fülöp G. Paragh Abdelouahed Khalil

Paraoxonase

Aryldialkylphosphatase

High-density lipoprotein

Low-density lipoprotein

10.1007/978-1-4020-6561-3_13

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Citations (2)

EFFECT OF COMPOST AND SOME STIMULTORY SUBSTANCES ON GLADIOLUS PLANT B. CORMS AND CORMELS PRODUCTIVITY AND CHEMICAL COMPOSITION

Scientific Journal of Flowers and Ornamental Plants /Scientific Journal of Flowers and Ornamental Plants (2021)

M. Abdou M. Aly Ahmed El-Sayed Abdelouahed Khalil Tarek Helmy

A field experiment was conducted during the two successive seasons of 2017/2018 and 2018/2019 in the Nursery and Laboratory of Ornamental Plants, Faculty of Agriculture, Minia University to study the effect of compost (7.5, 10.0 and 12.5 ton/fed) and seven treatments of stimulatory substances i.e. control, seaweeds extract (300 ppm), amino acids (200 ppm), ascorbic acid (100 ppm), salicylic acid (50 ppm), active yeast (5 g/l) and Minia azotein (50 ml/plant), as well as, their interaction on corms and cormels productivity of gladiolus and some chemical composition constituents.The obtained results indicated that the three levels of compost significantly increased corm diameter, number of cormels/plant, fresh weights/plant, as well as, chemical composition (photosynthetic pigments and N, P and K%) as compared to control.The maximum values were obtained by using compost at 12.5 ton/fed.Treated plants with any of six used stimulatory treatments considerably increased corm and cormels productivity and chlorophyll a, b and carotenoids content, as well as, the percentage of N, P and K in the leaves.Minia azotein was the most effective than the other treatments in this concern the interaction treatments were obtained due to fertilizing gladiolus with compost at 12.5 ton/fed and inoculation of the soil with either Minia azotein or with the sprayed plants with active yeast.

Gladiolus

Corm

10.21608/sjfop.2021.155930

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Citations (0)

Anaemia in CKD 1-5

Nephrology Dialysis Transplantation (2013)

Masayoshi Hirata Y. Tashiro Ken Aizawa Koichi Endo Michinori Hirata

10.1093/ndt/gft131

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Evaluation of the radiation-sensitizer/protector and/or antioxidant efficiencies using Fricke and PAG dosimeters

Journal of Physics Conference Series (2009)

Ridthee Meesat Jean‐Paul Jay‐Gerin Abdelouahed Khalil Martin Lepage

In this study, our aim is to assess the potential of Fricke and polyacrylamide gel (PAG) dosimeters to quantitatively evaluate the efficiency of potential radiation sensitizers/protectors and antioxidants. These compounds are of importance in radiotherapy as well as in disease prevention and promotion of health. The basic principle of the Fricke dosimeter is the radiation-induced oxidation of Fe2+ to Fe3+ in an aerated aqueous 0.4 M H2SO4. The production of ferric ions is most sensitive to the radical species produced in the radiolysis of water. Using this method, we observed that cystamine (one of the best of the known radioprotectors) can prevent oxydation of Fe2+ from reactive radiolysis species. However, one obvious disadvantage of the Fricke dosimeter is that it operates under highly acidic conditions (pH 0.46), which may degrade biological compounds. In contrast, the pH of the polyacrylamide gel (PAG) dosimeter is almost neutral, such that degradation of compounds is less probable. A change in R2-dose sensitivity was observed in the presence of radiosensitizers/radioprotectors and antioxidants. The protective effect of Trolox (a well-known antioxidant) and thiourea (a radioprotector) was readily observed using the PAG dosimeter. Incorporation of iodinated radiation sensitizers such as NaI and an iodine contrast agent led to a quantifiable sensitizer enhancement ratio. These studies suggest that the Fricke and the PAG dosimeters have the potential to evaluate the efficiency of radiation sensitizers/protectors and antioxidants.

10.1088/1742-6596/164/1/012006

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Citations (3)

High-Density Lipoprotein Metabolism and Function in Cardiovascular Diseases: What about Aging and Diet Effects?

Nutrients (2024)

Mojgan Morvaridzadeh Nada Zoubdane Javad Heshmati Mehdi Alami Hicham Berrougui

Cardiovascular diseases (CVDs) have become the leading global cause of mortality, prompting a heightened focus on identifying precise indicators for their assessment and treatment. In this perspective, the plasma levels of HDL have emerged as a pivotal focus, given the demonstrable correlation between plasma levels and cardiovascular events, rendering them a noteworthy biomarker. However, it is crucial to acknowledge that HDLs, while intricate, are not presently a direct therapeutic target, necessitating a more nuanced understanding of their dynamic remodeling throughout their life cycle. HDLs exhibit several anti-atherosclerotic properties that define their functionality. This functionality of HDLs, which is independent of their concentration, may be impaired in certain risk factors for CVD. Moreover, because HDLs are dynamic parameters, in which HDL particles present different atheroprotective properties, it remains difficult to interpret the association between HDL level and CVD risk. Besides the antioxidant and anti-inflammatory activities of HDLs, their capacity to mediate cholesterol efflux, a key metric of HDL functionality, represents the main anti-atherosclerotic property of HDL. In this review, we will discuss the HDL components and HDL structure that may affect their functionality and we will review the mechanism by which HDL mediates cholesterol efflux. We will give a brief examination of the effects of aging and diet on HDL structure and function.

High-density lipoprotein

Reverse cholesterol transport

10.3390/nu16050653

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Citations (8)

Long-term evolution of solitary skeletal osteochondromas

Foot and Ankle Surgery (2017)

K. Latrach Tlemsani Z. Talel R. Abderrazak Abdelouahed Khalil

10.1016/j.fas.2017.07.477

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Citations (0)

PON1 Paraoxonase Activity is Reduced During HDL Oxidation and is an Indicator of HDL Antioxidant Capacity

Free Radical Research (2002)

Leila Jaouad Christelle Milochevitch Abdelouahed Khalil

The aim of this study was to investigate the effect of HDL oxidation on PON1 paraoxonase activity. Also, we were interested in investigating the mechanism by which PON1 could be inactivated and the correlation between its enzymatic activity and the antioxidant properties of HDL. Three different oxidation systems were used for the HDL oxidation: (1) oxidation induced by THP1 cells, (2) oxidation induced by copper ions at a concentration 10 microM, and (3) oxidation induced by *OH and O2.- oxygen free radicals produced by gamma-radiolysis. HDL oxidation was followed by the measurement of lipid peroxide formation, and PON1 activity was determined by measuring the rate of paraoxon hydrolysis. Our results show that HDL oxidation is accompanied by a reduction in the PON1 paraoxonase activity. The extent of PON1 inactivation depends both on the extent of HDL oxidation and on the oxidation system used. The rates of HDL oxidation and PON1 inactivation were significantly correlated (r = 0.93, p < 0.0054). Our results show that oxidized HDL loses its protective effect toward LDL oxidation. The antioxidant action of HDL towards LDL oxidation and the degradation of PON1 paraoxonase activity were significantly correlated (r = 0.95, p < 0.04).

Paraoxonase

Aryldialkylphosphatase

Paraoxon

Lipid Oxidation

Peroxide

10.1080/1071576021000036614

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Citations (123)

4P-1014 Serum PON1 activities are reduced with ageing: effects on the antioatherogenic properties of HDL

Atherosclerosis Supplements (2003)

Abdelouahed Khalil Leila Jaouad Christelle Milochevitch

10.1016/s1567-5688(03)91271-2