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1.
Oncogene ; 32(42): 5101-10, 2013 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-23208508

RESUMO

One of the most conserved features of all cancers is a profound reprogramming of cellular metabolism, favoring biosynthetic processes and limiting catalytic processes. With the acquired knowledge of some of these important changes, we have designed a combination therapy in order to force cancer cells to use a particular metabolic pathway that ultimately results in the accumulation of toxic products. This innovative approach consists of blocking lipid synthesis, at the same time that we force the cell, through the inhibition of AMP-activated kinase, to accumulate toxic intermediates, such as malonyl-coenzyme A (malonyl-CoA) or nicotinamide adenine dinucleotide phosphate. This results in excess of oxidative stress and cancer cell death. Our new therapeutic strategy, based on the manipulation of metabolic pathways, will certainly set up the basis for new upcoming studies defining a new paradigm of cancer treatment.


Assuntos
Terapia de Alvo Molecular/métodos , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Ácido Graxo Sintase Tipo I/antagonistas & inibidores , Ácido Graxo Sintase Tipo I/metabolismo , Humanos , Masculino , Malonil Coenzima A/metabolismo , Camundongos Nus , NADP/metabolismo , NADPH Oxidases/metabolismo , Estresse Oxidativo , Ensaios Antitumorais Modelo de Xenoenxerto
2.
Eur J Clin Nutr ; 59(5): 727-30, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15798774

RESUMO

OBJECTIVE: To assess the antioxidant/non-antioxidant effects of a hydroxytyrosol (HT)-rich phenolic extract from olive mill wastewaters administered with a breakfast. DESIGN, SETTING AND SUBJECTS: Five type I diabetic patients received 25 mg of HT the first day and 12.5 mg/day the following 3 days. Blood sampling was carried out at T(0) (baseline) and T(4d) just before the breakfast + HT administration and at time points 1, 2, 3 and 4 h after T(0). Urines (24-h) were collected from T(0) to T(4d). Baseline HbA1c was generally inferior to 10%, glycemia was within the range 6-24 mmol/l, whereas total cholesterol, HDL-chol and triglycerides were normal. RESULTS: The major finding was the 46% decrease in the serum TXB(2) production after blood clotting at T(4d). Plasma vitamin A, E, beta-carotene were not changed. Vitamin C tended to increase (P = 0.075). Plasma antioxidant capacity was enhanced at T(0)+1 h only, whereas its main determinants (albumin, bilirubin, uric acid) were not modified. Urinary 8-isoPGF(2alpha) levels were highly variable and were not affected significantly by HT administration. CONCLUSION: The major effect of HT accounts for an antiaggregating platelet action, leading to a possible prevention of thrombotic and microthrombotic processes.


Assuntos
Antioxidantes/farmacologia , Diabetes Mellitus Tipo 1/sangue , Álcool Feniletílico/análogos & derivados , Óleos de Plantas/farmacologia , Tromboxano B2/sangue , Resíduos , Adulto , Idoso , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/urina , Dinoprosta/análogos & derivados , Dinoprosta/urina , Relação Dose-Resposta a Droga , Humanos , Masculino , Pessoa de Meia-Idade , Azeite de Oliva , Álcool Feniletílico/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Fatores de Tempo , Eliminação de Resíduos Líquidos/métodos
3.
J Nat Prod ; 64(4): 480-6, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11325231

RESUMO

Specific antioxidant activity (SAA) (i.e., activity related to the molar or gallic acid equivalent amount of antioxidant) of natural polyphenolic mixtures or pure phenolic compounds was studied using their capacity to delay the conjugated diene production brought about by in vitro LDL copper-mediated or AAPH-mediated oxidation. The cinnamic acid series (caffeic, sinapic, ferulic acids) displayed a constant SAA over a large range of concentrations, whereas the benzoic acid series (gallic and protocatechuic acids) showed much higher SAA at low concentrations. The natural phenolic mixtures had a constant SAA. The highest SAA was obtained with caffeoyl esters (caffeoylquinic, rosmarinic, and caffeoyltartaric acids) and catechin for the copper-oxidation and the AAPH-oxidation system, respectively. Phenolic mixtures and acids delayed vitamin E depletion and decreased proinflammatory lysophosphatidylcholine production. As with polyphenols, probucol delayed lysophosphatidylcholine and conjugated dienes production, at higher concentrations, but was not effective at preventing vitamin E depletion. Polyphenols prevent the oxidation of LDL and its constituents (vitamin E, phosphatidylcholine), which is compatible with an antiinflammatory and antiatherosclerotic role in pathophysiological conditions.


Assuntos
Antioxidantes/farmacologia , Ácidos Cafeicos/farmacologia , Mediadores da Inflamação/metabolismo , Lisofosfatidilcolinas/biossíntese , Fenóis/farmacologia , Humanos , Lipoproteínas LDL/sangue , Oxirredução
4.
Nephrol Dial Transplant ; 15(3): 389-95, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10692526

RESUMO

INTRODUCTION: Cardiovascular diseases represent the major cause of mortality in haemodialysis (HD) patients. Oxidized low-density lipoprotein (Ox-LDL) is a major cardiovascular risk factor, implicated in atherosclerotic plaque formation. It has been suggested that high-density lipoprotein (HD) has the capacity to reduce the oxidative modifications of LDL. The aim of this study is to analyse the protective effects of HDL in HD patients. METHODS: In vitro copper-induced LDL oxidation was evaluated in 12 patients with chronic renal failure (mean age 61.0+/-12.8 years) and compared to 25 healthy subjects (mean age 57.3+/-19.2 years). LDL were incubated in oxygen-saturated PBS, LDL oxidation was initiated by Cu (II) in the presence and absence of HDL and assessed by measuring the absorbance (abs) increase at 234 nm due to conjugated diene formation. Duration of lag time, maximum velocity (V(max.)) of lipid peroxidation, oxidation slope and half-time of maximum diene formation (T (1/2)) were obtained by kinetic modelling analysis. RESULTS: HDL (1.06+/-0.31 vs 1.23+/-0.39 mmol/l) and Apo AI (1. 17+/-0.39 vs 1.49+/-0.20 g/l) levels were decreased in HD patients. In the absence of HDL, LDL obtained from HD patients showed an enhanced susceptibility to oxidation in vitro as demonstrated by the significant decrease in lag time (54.5+/-22.2 vs 79.4+/-37.8 min) and a significant increase in V(max.) (0.026+/-0.006 vs 0.017+/-0. 005 abs/min). In all cases, HDL (from 0.1 to 2 microM) prevented LDL oxidation in vitro; however, this effect was significantly reduced in HD patients: increase in lag time 54.2% vs 150.4% in HD vs controls; increase in T (1/2) 52.2% vs 124.6% in HD vs controls; decrease in V(max). 13.5% vs 38.5% in HD vs controls. CONCLUSIONS: These results suggest that qualitative abnormalities such as an impairment of HDL-associated enzymes are associated with a decrease of HDL levels during HD. Hence, in addition to the known impairment of reverse cholesterol transport, the reduction of HDL protective capacity against oxidative stress could be involved in the development of HD-induced atherosclerosis.


Assuntos
Lipoproteínas HDL/fisiologia , Estresse Oxidativo/fisiologia , Diálise Renal/efeitos adversos , Adulto , Idoso , Cobre/farmacologia , Feminino , Humanos , Falência Renal Crônica/sangue , Lipídeos/sangue , Lipoproteínas/sangue , Lipoproteínas LDL/metabolismo , Masculino , Pessoa de Meia-Idade , Oxirredução/efeitos dos fármacos
5.
Bull Soc Pathol Exot ; 91(3): 238-41, 1998.
Artigo em Francês | MEDLINE | ID: mdl-9773200

RESUMO

Lipoperoxidation final products represented by the TBARS (substances reacting with the Thiobarbituric acid), inflammatory reaction proteins and sera tocopherol have been studied in homozygous forms as well as in heterozygous forms of sickle cell diseases. The significant increase of TBARS (P < 0.001) measured by spectrofluorimetry, the considerable decrease of the sera alpha gamma tocopherol, measured by HPLC (P < 0.005) in all sickle cell patients, especially in crisis homozygous form, reinforce our previous study (22, 23, 24). The absence of links between the TBARS and the tocopherols (fig. 1) suggests that other defence mechanisms occur without vitamin E. The collapse of haptoglobinemia in homozygous sickle cell patients associated with the fall of hemoglobinemia indicates a severe tissue and intravascular hemolysis as a consequence of LPO. Furthermore, the simultaneous decrease of cholesterolemia seems to indicate important lipoperoxide activity detected in sickle cell patients.


Assuntos
Proteínas de Fase Aguda/análise , Anemia Falciforme/sangue , Biomarcadores/sangue , Genótipo , Peroxidação de Lipídeos , Vitamina E/sangue , Adolescente , Adulto , Anemia Falciforme/genética , Cromatografia Líquida de Alta Pressão , Heterozigoto , Homozigoto , Humanos , Pessoa de Meia-Idade , Espectrometria de Fluorescência , Substâncias Reativas com Ácido Tiobarbitúrico/análise
6.
Eur J Clin Nutr ; 51(10): 682-90, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9347289

RESUMO

OBJECTIVES: To evaluate the effect of the red wine phenolic compound (RWPC) dietary supplementation without alcohol interference on: (1) some of the biochemical characteristics of LDL, (2) the oxidative susceptibility of LDL and (3) the antioxidant capacity of total plasma (Pl-AOC). In order to account for discrepancies between the three series of data, the in vitro stability of the association of phenolic compounds and LDL was tested. DESIGN: An intervention study with 20 volunteers. Each served as his own control. Cu(2+)-oxidizability of LDL and Pl-AOC were tested on blood samples before and after dietary supplementation. Cu(2+)-oxidizability of LDL was also tested by co-incubation in the presence of RWPC or phenolic acids with or without extensive dialysis. SETTING: The Laboratory of Lipid Biochemistry and Biology, School of Medicine, and the Laboratory of Metabolic Diseases, Lapeyronie Hospital, University of Montpellier, France. SUBJECTS: Healthy males, nonsmokers and moderate drinkers, submitted to a dietary regimen deprived of vitamin E and C for a period of 10 d before supplementation. They also abstained from alcohol, wine, fruit juices, coffee, tea and cola beverages during this period. INTERVENTION: Six 0.33 g capsules/d (namely two capsules at each meal) of a preparation of red wine phenolic compounds in a dry powder form were given to the volunteers over a period of two weeks. Blood samples were drawn in fasting conditions at day 0 and day 14 of the supplementation period. RESULTS: Supplementation led to: (1) in LDL, a significant increase in vitamin E content (n = 20, P = 0.01) or vitamin E/total fatty acid bis-allylic carbon number ratio (n = 20, P = 0.006) without modification in the other biochemical characteristics or Cu(2+)-oxidizability; (2) in plasma, a significant increase in the antioxidant capacity (n = 11, P = 0.01). In vitro studies showed that RWPC or sinapic, caffeic or ferulic acids incubated in the presence of LDL increased the protection of the lipoparticle against oxidation (caffeic > sinapic > ferulic). This effect, however, was totally lost after extensive dialysis. CONCLUSIONS: The enhancing effect of the RWPC supplementation on Pl-AOC may be due to a phenolic-compound action both in the aqueous phase of plasma and at the surface of lipoprotein particles. Surface location possibly explains the enhancing-sparing effect of supplementation on LDL vitamin E and the absence of effect on dialysed-LDL oxidizability.


Assuntos
Antioxidantes , Cobre/sangue , Lipoproteínas LDL/sangue , Fenóis/farmacologia , Vitamina E/sangue , Vinho/análise , Adulto , Antioxidantes/farmacologia , Ácidos Cafeicos/farmacologia , Ácidos Cumáricos/farmacologia , Sequestradores de Radicais Livres/farmacologia , Humanos , Masculino , Oxirredução
7.
Nephron ; 69(4): 404-10, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7777104

RESUMO

To investigate the effects of erythropoietin (rHuEPO) therapy supplemented or not with iron on hemolysis in hemodialysed patients (HD) we evaluated lipoperoxidation (LPO) by assaying (i) the red blood cell (RBC) antioxidant enzymatic system including superoxide dismutase (SOD), glutathione peroxidase, and catalase (Cat), (ii) RBC polyunsaturated fatty acids (PUFA) and (iii) malondialdehyde (MDA). Group 1 included 12 HD patients, group 2 had 7 HD patients with iron supplementation, group 3 comprised 12 HD patients with rHuEPO therapy and group 4 included 9 HD patients with both iron and rHuEPO therapies. No LPO was found in group 1 as regards MDA and PUFA levels. However, SOD and Cat activities were significantly elevated as compared to controls (p < 0.001). In the second group, a significant decrease in PUFA percentage was observed, particularly in 20:4(n-6) and 22:4(n-6) (the main ones involved in LPO) as compared to the other groups, whereas total MDA level was higher than that of the other groups. Similarly a decreased SOD activity was observed as compared to group 1 (p < 0.001), indicating its inactivation subsequent to an hyperproduction of reactive oxygen species through iron injection. In groups 3 and 4 no change was observed in MDA levels or PUFA percentages indicating no LPO. However, marked differences were observed in the enzymatic defense system. Particularly in group 3, SOD and Cat activities decreased when compared to group 1 (p < 0.001) whereas the association of erythropoietin and iron (group 4) increased the three enzymatic activities (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Eritrócitos/metabolismo , Eritropoetina/uso terapêutico , Peroxidação de Lipídeos , Diálise Renal , Adulto , Idoso , Anemia/sangue , Anemia/tratamento farmacológico , Anemia/etiologia , Catalase/sangue , Eritrócitos/efeitos dos fármacos , Ácidos Graxos Insaturados/sangue , Feminino , Glutationa Peroxidase/sangue , Humanos , Ferro/administração & dosagem , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Diálise Renal/efeitos adversos , Superóxido Dismutase/sangue , Uremia/sangue , Uremia/complicações , Uremia/terapia
8.
Free Radic Biol Med ; 16(3): 339-46, 1994 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8063197

RESUMO

In 14 patients undergoing haemodialysis, lipoperoxidation (LPO) processes were determined in plasma and red blood cells (RBC) before and after a dialysis session by determining (a) the direct substrate, polyunsaturated fatty acids (PUFA); (b) the end product of LPO, malondialdehyde (MDA); and (c) the hydrophobic antioxidant systems, vitamins A and E. In plasma before dialysis, linoleic and arachidonic acid, and the antioxidant vitamin E, were significantly lowered as compared to the healthy controls (p < 0.05). On the contrary, the free MDA level was enhanced (p < 0.05). These results were emphasized by a dialysis session. In RBC of these patients, no difference in linoleic acid, free MDA, or vitamin E level were observed before or after dialysis when compared to controls. However, only vitamin A was significantly higher in haemodialysis patients (before and after dialysis) and in renal failure patients (p < 0.05) than in the healthy control group. The present results suggest that increased RBC vitamin A may offer some degree of protection against oxidative stress in erythrocytes, but not in plasma where LPO is demonstrated.


Assuntos
Peroxidação de Lipídeos , Diálise Renal/efeitos adversos , Adulto , Idoso , Eritrócitos/metabolismo , Ácidos Graxos Insaturados/sangue , Feminino , Radicais Livres , Humanos , Ferro/sangue , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Plasma/metabolismo , Uremia/sangue , Uremia/terapia , Vitamina A/sangue , Vitamina E/sangue
9.
Ann Biol Clin (Paris) ; 52(3): 171-7, 1994.
Artigo em Francês | MEDLINE | ID: mdl-7998672

RESUMO

In 3-month-old Wistar rats carrageenan and CCl4 injected intraperitoneally induce an acute phase reaction which is characterized by a marked increase in alpha 1, alpha 2, beta serum globulins. This reaction corresponds to a large increase in these globulins in the first case and a smaller one in the second. A lipoperoxidant effect is demonstrated by the serum lipoprotein mobility as the lipoperoxidation index (in MDA units) or the decrease in serum vitamin A and E concentrations. This effect is also greater in the first case than in the second one. In the same way the lipoperoxidant effect is shown in liver microsomes but with a lower amplitude in the first case than in the second one. The treatment of rats by intraperitoneal injection of diosmine (150 mg/kg per week) during the 8 weeks which precede the injection of carrageenan or CCl4 results in: i) a marked decrease in the acute-phase reaction and a lower one in the lipoperoxidant effect, in serum; ii) a decrease in the CCl4 induced lipoperoxidant effect in liver microsomes. It may be concluded that diosmine, not injected at the same time as carrageenan or CCl4, but during the previous 8 weeks is sufficiently well distributed in the whole body to produce a marked inhibition of the acute phase reaction and a perceptible effect on lipoperoxidation. It may be considered an effective complement to the natural antioxidant defences of the organism (vitamins A and E).


Assuntos
Diosmina/farmacologia , Peróxidos Lipídicos/sangue , Reação de Fase Aguda/sangue , Reação de Fase Aguda/induzido quimicamente , Animais , Tetracloreto de Carbono/farmacologia , Carragenina/farmacologia , Diosmina/administração & dosagem , Injeções Intraperitoneais , Masculino , Ratos , Ratos Wistar
10.
Ann Biol Clin (Paris) ; 52(4): 265-70, 1994.
Artigo em Francês | MEDLINE | ID: mdl-7802350

RESUMO

Diosmin (DI) 3'5,7-trihydroxy-4'-methoxy flavone rutinoside is a member of the flavonoid family, some of whom have antioxidant or free radical scavenger properties. Paw oedema induced by doxorubicin in rats is reduced by DI as observed by SAUVAIRE et al (1989). This suggests a free radical scavenger activity for DI. In this work we demonstrate that such activity is able to protect isolated human LDL from oxidation in vitro. The study of the electrophoretic mobility of oxidized LDL and of total-MDA values as lipoperoxidation-marker indicates an oxidation inhibiting effect higher than 70% for 0.16 mM DI in LDL mixtures containing 50 mM Cu2+ or 4.3 mU/ml xanthine-oxidase and incubated during 20 and 6 hours respectively. Owing to the high level of the oxidizing conditions and the vitamin E (48 mM), vitamin A (1.4 mM) and beta-carotene (2.4 mM) content of the LDL mixtures, it is concluded that DI is clearly able to complement the antioxidant effect of isoprenoids which are naturally present in LDL mixtures.


Assuntos
Diosmina/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Adulto , Eletroforese em Gel de Ágar , Feminino , Humanos , Técnicas In Vitro , Lipoproteínas LDL/química , Lipoproteínas LDL/metabolismo , Masculino
11.
Food Addit Contam ; 9(1): 1-9, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1397387

RESUMO

The effects of retinol and alpha-tocopherol-deficient and supplemented diets on the cytosolic concentration of thiobarbituric acid reactive substances (TBARS) in rat liver have been studied. Physiological lipoperoxidation (LPO) was observed in liver cytosol of control rats (TBARS = 0.315 +/- 0.034 nmol of MDA equivalents/mg of liver cytosolic proteins). In retinol-deficient diets there was a decrease in retinolaemia and the absence of retinol in liver cytosol while cytosolic TBARS increased significantly (P less than 0.001). Vitamin E was not found in cytosolic fractions, except in alpha-tocopherol-supplemented diet rats. alpha-Tocopherol-deficient diets induced an absence of vitamin E in the serum and cytosolic TBARS were increased compared to controls (P less than 0.001). Supplementation of the diet with retinol and alpha-tocopherol or both in combination induced a significant decrease in liver cytosolic TBARS (P less than 0.001). Finally the combination of low dietary supplementation with retinol and alpha-tocopherol (ten times the normal diet each) induced the maximum anti-LPO effect.


Assuntos
Peroxidação de Lipídeos , Fígado/metabolismo , Vitamina A/administração & dosagem , Vitamina E/administração & dosagem , Animais , Peso Corporal , Citosol/metabolismo , Fígado/anatomia & histologia , Masculino , Tamanho do Órgão , Ratos , Ratos Wistar , Vitamina A/análise , Vitamina A/sangue , Vitamina E/análise , Vitamina E/sangue
12.
Bull Soc Pathol Exot ; 85(2): 174-9, 1992.
Artigo em Francês | MEDLINE | ID: mdl-1327359

RESUMO

The present study report 7 cases of sickle homozygous disease which have been analysed using markers of the oxidative-stress, 26 african male subjects were studied: 7 Hb SS subjects (age: m = 20) and 19 control subjects (Hb AA, age: m = 40). Plasma concentrations of F-MDA, T-MDA, TBARS, alpha tocopherol, retinol and beta carotene were measured. Plasma MDA and TBARS mean levels increased in sickle homozygous patients more than in controls. However, only TBARS mean concentrations were significantly increased between patients and controls: TBARS: 4.14 +/- 1.49 nMol/ml for Hb SS versus 2.10 +/- 1.21 nMol/ml for Hb AA (P less than 0.005). Vitamin A and vitamin E concentrations were significantly lower in Hb SS than in Hb AA. Beta carotene was significantly increased in patients vs controls. The significant increase of TBARS explains the great importance of the oxidative damage, whereas the significant decrease of vitamins A and E, may contribute, at least for a part, to maintain the autoxidation process or reveals its intensity in these patients.


Assuntos
Traço Falciforme/sangue , Adolescente , Adulto , Criança , Pré-Escolar , Homozigoto , Humanos , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Oxirredução , Traço Falciforme/genética
13.
Clin Chem ; 37(8): 1423-9, 1991 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1868605

RESUMO

Assay of free and total malondialdehyde (MDA) in human serum and plasma from healthy subjects and from patients with high risk of lipoperoxidation was performed as follows: (a) acidic (HClO4, pH 1, at 20 degrees C) or basic (NaOH, pH 13, at 60 degrees C) treatments for 30 min; (b) reaction of the protein-free extract (obtained by acid precipitation) with thiobarbituric acid (TBA); (c) HPLC separation on C18 columns with an eluting solution of methanol/phosphate buffer, 10 mmol/L, pH 5.8 (40/60, by vol), at a flow rate of 1.5 mL/min. Free MDA averaged 0.042 (SEM 0.008) and 0.043 (SEM 0.007) mumol/L, respectively, in serum and plasma from healthy subjects. Free (+/- SEM) MDA increased significantly in the plasma from cancer patients (0.270 +/- 0.047 mumol/L) and from hemodialyzed patients (0.214 +/- 0.035 mumol/L). In serum of hemodialyzed patients, analyses for total MDA were unsuitable because of interfering peaks. MDA bound to NH2 groups constituted 83.2% and 83.5% of total MDA in serum and plasma of healthy subjects, respectively, and only 58% in plasma of hemodialyzed patients.


Assuntos
Malondialdeído/sangue , Tiobarbitúricos/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Cromatografia Líquida de Alta Pressão , Cromatografia em Camada Fina , Feminino , Humanos , Peroxidação de Lipídeos , Masculino , Pessoa de Meia-Idade , Neoplasias/sangue , Diálise Renal , Tiobarbitúricos/química
14.
Food Addit Contam ; 7 Suppl 1: S182-7, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2262031

RESUMO

A study was conducted to explore the free radical inhibitor effect of retinol in Male Wistar rats. When retinol-deprived animals were considered retinol-depleted (after a period of 8 weeks), rats of each group, control and depleted, received an intraperitoneal injection of mineral oil (5 ml/kg body weight) or an equivalent volume of 20% carbon tetrachloride (CCl4) dissolved in mineral oil. The animals were killed by decapitation 4 h after administration of CCl4 and liver, heart, spleen, brain and testes were quickly removed. Minced tissues were homogenized and microsomes were prepared; vitamins A and E were monitored and malondialdehyde (MDA) content was estimated. Retinol-depleted rats showed an hepatic vitamin A level less than 10 pmol/mg protein, compared to control rats (15-45 pmol). In all hepatic preparations, we found low vitamin E levels (100-1300 pmol/mg protein). MDA production increased significantly in livers and hearts of retinol-depleted rats but not in brains, spleens and testes. Hearts contain less lipids and vitamin E than these latter organs, which could correlate with the highest production of MDA.


Assuntos
Intoxicação por Tetracloreto de Carbono/metabolismo , Microssomos Hepáticos/metabolismo , Vitamina A/uso terapêutico , Animais , Radicais Livres , Peroxidação de Lipídeos , Masculino , Malondialdeído/análise , Malondialdeído/farmacocinética , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/patologia , Óleo Mineral/administração & dosagem , Óleo Mineral/farmacologia , Ratos , Ratos Endogâmicos , Distribuição Tecidual , Vitamina A/administração & dosagem , Deficiência de Vitamina A/tratamento farmacológico , Deficiência de Vitamina A/metabolismo
15.
Food Addit Contam ; 7 Suppl 1: S35-40, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2262037

RESUMO

Malondialdehyde (MDA) is a product of lipid peroxidation in vivo. The most widely employed method for determination of free MDA is based on its reaction with thiobarbituric acid (TBA) which produces a pink pigment with an absorption maximum at 532-535 nm. However, quantitation of MDA is limited by its lack of specificity and a high performance liquid chromatographic (HPLC) method was recently developed in several laboratories. In the present study, free MDA levels were measured, after TBA reaction, spectrophotometrically and by HPLC in microsomes of different tissues from rats fed a vitamin A-deficient diet or not for 8 weeks, and treated or not with carbon tetrachloride. Incubation in vitro with NADPH (0.25 mM) or ascorbate (0.50 mM) in the presence of Fe2+ (5 microM)-ADP (0.5 mM), allowed us to estimate the total amount of enzymatic or non enzymatic lipoperoxidation. The MDA amount determined by HPLC is significantly lower than the TBA-reactive substances (TBA-RS) calculated spectrophotometrically as MDA equivalents. Moreover, HPLC separations performed on a mu Bondapack C18 column with a mobile phase of methanol/water 45/55 (v/v), containing 1% cetrimide revealed that three chromogens are present in microsomes incubated with ascorbate or NADPH. The TBA-RS visible spectra of microsomes incubated with activator are complex with an absorption maximum at 533 nm, which is specific for the MDA-TBA chromogen, and one at 450 nm. Identification of these TBA-RS, different from the MDA-TBA complex, is under investigation in our laboratory.


Assuntos
Intoxicação por Tetracloreto de Carbono/metabolismo , Malondialdeído/análise , Deficiência de Vitamina A/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Peroxidação de Lipídeos , Masculino , Microssomos/metabolismo , Ratos , Ratos Endogâmicos , Espectrofotometria
16.
Electrophoresis ; 10(11): 766-71, 1989 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2558884

RESUMO

Distribution and cellular levels of retinol-binding protein and retinoic acid-binding protein, involved in the molecular action of retinoids, were analyzed in rat testis and liver. Both binding proteins of cytosolic extracts were separated by linear-polyacrylamide gradient gel electrophoresis and following electrophoretic separation, could be visualized by complementary identification tests such as autoradiography and marker proteins. The concentration of the binding proteins were evaluated by scanning the polyacrylamide gradient gels and the resulting data were found to be in accordance with those obtained by counting radioactivities. Polyacrylamide gradient gel electrophoresis appears suitable to detect and quantitatively evaluate cytosolic retinol- and retinoic acid-binding proteins.


Assuntos
Proteínas de Transporte/análise , Eletroforese em Gel de Poliacrilamida/métodos , Fígado/análise , Testículo/análise , Vitamina A/análise , Animais , Autorradiografia , Citosol/análise , Masculino , Ratos , Ratos Endogâmicos , Receptores de Superfície Celular/metabolismo , Receptores do Ácido Retinoico
17.
Arch Biochem Biophys ; 275(1): 244-51, 1989 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-2817898

RESUMO

The possible role of carotenoids as free radical scavengers has not been completely elucidated. To gain further insight into the quenching of OH radicals by carotenoids, we used a feasible bacterial model, Deinococcus radiodurans, a red pigmented bacterium. We compared the action of H2O2 which produces in vivo OH radicals by a Fenton-type reaction on the parental and two mutant strains, i.e., a red pigmented and a colorless one. While the red pigmented bacteria were resistant to H2O2 action, the colorless strain was significantly more sensitive and its sensitivity was dose-dependent. In the red pigmented strains, H2O2 induced a significant decrease in one carotenoid (X5), which could be responsible for the antioxidant activity.


Assuntos
Carotenoides/metabolismo , Bactérias Gram-Positivas/metabolismo , Peróxido de Hidrogênio/farmacologia , Carotenoides/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Desferroxamina/farmacologia , Radicais Livres , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/genética , Cinética , Mutação , Especificidade da Espécie
18.
Biochimie ; 69(11-12): 1243-50, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-3129029

RESUMO

The lipid composition of D. radiodurans strain R1 and of two mutant strains has been studied in relation to membrane fluidity and sensitivity to X-ray radiation. No significant difference in the unsaturation degree of fatty acids was found between parental and mutant strains. An important decrease of carbohydrate-containing lipids was observed in the radiosensitive mutant strain. We also observed a higher fluidity in both mutant strains than in the parental one. Modification of membrane lipid fluidity by growing the parental strain at 39 degrees C did not lead to modified radioresistance. These results suggest that a particular chemical composition of the membrane leading to a special lipid phase may be an important parameter in controlling radiosensitivity.


Assuntos
Lipídeos/análise , Carboidratos/análise , Mutação , Especificidade da Espécie , Raios X
19.
Biochimie ; 68(10-11): 1201-9, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3098304

RESUMO

Fatty acid composition and lipidic carbohydrate to lipidic phosphorus molar ratio of yellow pigmented micrococci are compared to red pigmented ones and may be summarized by three indexes. These bacteria show wide differences in their fatty acid composition: three strains possess saturated branched chain fatty acids and one has unsaturated straight chain ones. A significant increase in 'anteiso/iso indexes' is observed between pink (M. roseus) and yellow colored bacteria (M. lysodeikticus, S. lutea). There is no significant difference (P greater than 0.05) between the 'unsaturation indexes' of the red pigmented parental D. radiodurans strain and its colorless mutant. Radioresistant strains exhibit a higher 'carbohydrate/phosphorus index' than other strains. There seems to be a relationship between a high carbohydrate-containing lipid content and a high resistance to physical and chemical agents, in particular to radiations. These differences observed in the lipid composition have implications in taxonomy and in establishing an evolutionary scheme.


Assuntos
Carboidratos/análise , Ácidos Graxos/análise , Lipídeos de Membrana/análise , Micrococcus/análise , Fósforo/análise , Tolerância a Radiação , Espectrofotometria
20.
Biochimie ; 66(4): 319-30, 1984 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6331531

RESUMO

Deinococcus radiodurans, although a gram-positive bacterium, has a complex cell wall with multiple layers and associates to this structural particularity, a quite unusual lipid composition for gram-positive bacteria. The conventional phospholipids (phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl glycerol...) are absent. Among the nine polar lipids detected in the R1 Anderson strain, three are glycolipids only one is a phospholipid, the other ones are glycophospholipids. One of the latter compounds contains one free amino group. Analysis by aminoacid autoanalyser enables to identify glucosamine in one glycolipid and in two glycophospholipids. Sugar analysis by gas-liquid chromatography after acid methanolysis and trifluoroacetylation, reveals the occurrence of N-acetyl glucosaminyl residues in one glycolipid and in one phospholipid. The following identification for the two lipids of D. radiodurans is proposed: phosphatidyl glucosaminyl glycerol and phosphatidyl N-acetyl glucosaminyl glycerol.


Assuntos
Bactérias Gram-Positivas/análise , Fosfolipídeos/análise , Acetatos , Ácido Acético , Fenômenos Químicos , Química , Cromatografia Gasosa , Glicolipídeos/análise , Hidrólise , Ácido Periódico , Fosfatidilgliceróis/análise
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