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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The characteristics of vesicles formed from Dipalmitoyl Phosphatidyl Choline (DPPC) are sensitive to the presence of perturbing molecules such as drugs, peptides, hormones and vitamins. We have used ESR spin labeling and NMR techniques for studying interaction of such molecules with lipid bilayers. ESR spin labeling has been used to monitor thermotropic behaviour of model membranes. Different NMR probes such as 1H, 31P, 13C have been used to gather information regarding the mode of interaction. It has been observed that the model membrane systems respond differently depending upon the localization of the perturbing molecules in the lipid bilayer. Small molecules such as neurotransmitters epinephrine and norepinephrine decrease gel to liquid crystalline phase transition temperature significantly even when present in small amounts. Vitamin E acetate having a hydrophobic hydrocarbon tail orients parallel to the lipid molecule and thereby exhibits dynamics similar to palmitate chain. When the acetate group is replaced by hydroxyl group (alpha-tocopherol), the phase transition becomes broad and the lipid molecules loose freedom of lateral diffusion. This can be attributed to formation of hydrogen bond between the hydroxyl group of alpha-tocopherol and phosphate moiety of lipid. The conformation of antidepressants nitroxazepine and imipramine is significantly altered when embedded in lipid bilayer. Anaesthetic etomidate not only modifies thermotropic characteristics but also induces polymorphism. The normal bilayer arrangement of lipids gets transformed into hexagonal packing. Amino acid tryptophan induces cubic phases in the normal bilayer arrangement of DPPC dispersions. Peptide gonadoliberin shows a reduced internal motion due to the lipid peptide interaction. The major consequences of binding of lipids with externally added molecules are changes in the fluidity and permeability properties of membranes. It has been shown that permeability is effected by the presence of molecules such as propranolol, alpha-tocopherol and its analogue, neurotransmitters, etc. The magnetic resonance methods have thus evolved as power techniques in the study of membrane structure and function.
Mol Cell Biochem
PMID:Effect of incorporation of drugs, vitamins and peptides on the structure and dynamics of lipid assemblies. 269 35

Vitamin E, a lipophilic antioxidant, has effectively inhibited the activation of cytokine-induced nuclear factor kB (NFkB). Since NFkB plays a critical role in the induction of an isoform of nitric oxide synthase (iNOS) gene by lipopolysaccharide (LPS), we investigated the effect of a vitamin E derivative, pentamethyl-hydroxychromane (PMC), which is an extremely potent inhibitor of NFkB activation, on the induction of nitric oxide (NO) synthesis and iNOS mRNA by LPS. PMC inhibited the LPS-stimulated induction of NO production in a concentration-dependent fashion in cultured J774 macrophages and rat vascular smooth muscle cells without evidence of cytotoxicity. However, the addition of PMC to J774 macrophages after the induction of iNOS did not inhibit NO production. Treatment of J774 macrophages with LPS resulted in a significant expression of iNOS mRNA, which was profoundly reduced by PMC. Data suggest that PMC inhibits the induction of iNOS by preventing iNOS gene expression through inhibition of NFkB activation.
Biochem Mol Biol Int 1995 Jan
PMID:Pentamethyl-hydroxychromane, vitamin E derivative, inhibits induction of nitric oxide synthase by bacterial lipopolysaccharide. 753 70

It is established that acetaminophen exhibits oxidative behaviour. The effects of acetaminophen (0.3-14.5 microM) on methemoglobin levels, superoxide dismutase and Na(+)-K+ ATPase activities of normal and vitamin E or vitamin C pretreated erythrocytes were investigated. In acetaminophen incubated erythrocytes, methemoglobin concentration and superoxide dismutase activity were increased in a dose and incubation-time dependent manner, the activity of Na(+)-K+ ATPase was decreased by acetaminophen treatment. Vitamin E (1mg/dl of erythrocyte suspension) or vitamin C (1mg/dl of erythrocyte suspension) provided partial protection of hemoglobin, superoxide dismutase and Na(+)-K+ ATPase against acetaminophen action. Vitamin E was more effective than vitamin C.
Biochem Mol Biol Int 1995 Apr
PMID:Effects of acetaminophen on methemoglobin, superoxide dismutase and Na(+)-K+ ATPase activities of human erythrocytes. 762 22

The generation of free oxygen radicals is believed to play an important pathogenic role in the development of various disorders. More than other tissues, the skin is exposed to numerous environmental chemical and physical agents such as ultraviolet light causing oxidative stress. In the skin this results in several short- and long-term adverse effects such as erythema, edema, skin thickening, wrinkling, and an increased incidence of skin cancer or precursor lesions. However, accelerated cutaneous aging under the influence of ultraviolet light, usually termed photoaging, is only one of the harmful effects of continual oxygen radical production in the skin. Others include cutaneous inflammation, autoimmunological processes, keratinization disturbances, and vasculitis. Vitamin E is the major naturally occurring lipid-soluble non-enzymatic antioxidant protecting skin from the adverse effects of oxidative stress including photoaging. Its chemistry and its physiological function as a major antioxidative and anti-inflammatory agent, in particular with respect to its photoprotective, antiphotoaging properties, are described by summarizing animal studies, in vivo tests on human skin and biochemical in vitro investigations. The possible therapeutic use in different cutaneous disorders, and pharmacological and toxicological aspects are discussed. Many studies document that vitamin E occupies a central position as a highly efficient antioxidant, thereby providing possibilities to decrease the frequency and severity of pathological events in the skin. For this purpose increased efforts in developing appropriate systemic and local pharmacological preparations of vitamin E are required.
J Mol Med (Berl) 1995 Jan
PMID:The role of vitamin E in normal and damaged skin. 763 44

Thirty-two typical patients with breast cancer, aged 32-81 years and classified 'high risk' because of tumor spread to the lymph nodes in the axilla, were studied for 18 months following an Adjuvant Nutritional Intervention in Cancer protocol (ANICA protocol). The nutritional protocol was added to the surgical and therapeutic treatment of breast cancer, as required by regulations in Denmark. The added treatment was a combination of nutritional antioxidants (Vitamin C: 2850 mg, Vitamin E: 2500 iu, beta-carotene 32.5 iu, selenium 387 micrograms plus secondary vitamins and minerals), essential fatty acids (1.2 g gamma linolenic acid and 3.5 g n-3 fatty acids) and Coenzyme Q10 (90 mg per day). The ANICA protocol is based on the concept of testing the synergistic effect of those categories of nutritional supplements, including vitamin Q10, previously having shown deficiency and/or therapeutic value as single elements in diverse forms of cancer, as cancer may be synergistically related to diverse biochemical dysfunctions and vitamin deficiencies. Biochemical markers, clinical condition, tumor spread, quality of life parameters and survival were followed during the trial. Compliance was excellent. The main observations were: (1) none of the patients died during the study period. (the expected number was four.) (2) none of the patients showed signs of further distant metastases. (3) quality of life was improved (no weight loss, reduced use of pain killers). (4) six patients showed apparent partial remission.
Mol Aspects Med 1994
PMID:Apparent partial remission of breast cancer in 'high risk' patients supplemented with nutritional antioxidants, essential fatty acids and coenzyme Q10. 775 35

The anticarcinogenic activity of alpha-tocopherol (Vitamin E) was tried in fibrosarcoma induced rats through its antioxidative potential. The rate of formation of malondialdehyde (MDA), the end product of lipid peroxidation was analysed in alpha-tocopherol (400 mg/kg body weight) treated and untreated fibrosarcoma bearing rats with respective controls. The levels of non-enzymic antioxidants like, glutathione and vitamin E, and enzymic antioxidants viz., catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and glutathione-S-transferase (GST) were assayed as well. Significantly increased (p < 0.001) level of lipid peroxide was observed with concomitant decreases in the level of enzymic and non-enzymic antioxidants in fibrosarcoma bearing rats when compared with control animals. In alpha-tocopherol supplemented animals, the corrected level of these parameters were observed likely to near normal values. Thus, alpha-tocopherol can be accepted to pose first line of defense mechanism against excessively formed reactive species due to impaired antioxidant systems in fibrosarcoma conditions, that cause membrane damage leading to deleterious effects.
Mol Cell Biochem 1994 Feb 23
PMID:Effect of alpha-tocopherol on lipid peroxidation and antioxidant system in fibrosarcoma bearing rats. 803 77

Laser Doppler Electrophoresis was used to detect changes in the surface charge of low density lipoprotein populations exposed to oxidative stress. Before oxidative stress, low density lipoprotein suspensions exhibited homogenous populations of net negative charge but after exposure to hydroxyl and superoxide radicals, peroxyl radicals, or by Cu2+ generated oxidants they exhibited Laser Doppler Electrophoresis changes. The major population of low density lipoprotein became more negatively charged, in agreement with agarose gel electrophoresis. However, Laser Doppler Electrophoresis detected greater heterogeneity of low density lipoprotein, compared to agarose gel electrophoresis. Partially oxidized low density lipoprotein exhibited a less negatively charged subpopulation of particles compared to control samples. This has not been reported previously. Hence, Laser Doppler Electrophoresis is a sensitive method for detecting the appearance of subpopulations of differing surface charge density in oxidatively modified low density lipoprotein. beta-carotene protected low density lipoprotein against oxidative modification even when endogenous vitamin E levels are low. Vitamin E-deficient low density lipoprotein pretreated with beta-carotene exhibited a more narrow negative population when oxidized with peroxyl radicals, compared to control. Native low density lipoprotein pretreated with a mixture of all-trans- and cis-beta-carotene was also protected.
Biochem Mol Biol Int 1993 Aug
PMID:Electrophoretic mobility changes of oxidized human low density lipoprotein measured by laser Doppler electrophoresis. 822 Feb 56

Subjects at high risk for colon cancer received different doses of fish oil on a 30-day randomized double-blind trial to evaluate the chemopreventive effect of n-3 fatty acids against colorectal cancer. Using rectal mucosal proliferation, assessed with 3H-thymidine autoradiography, fish oil induced in the treated groups but not in the placebo group a change in the proliferative pattern, which resulted similar to that observed in low risk population; in the same groups rectal mucosal n-3 fatty acid content increased, where arachidonic acid level decreased. Moreover, n-3 PUFA treatment induced modifications of Vitamin E status. The results suggest that n-3 PUFA could protect high-risk subjects from colon cancer by a mechanism involving a modulation of Vitamin E.
Mol Aspects Med 1993
PMID:n-3 PUFA and alpha-tocopherol control of tumor cell proliferation. 826 39

Vitamin E had an enhancing effect on active oxygen generation in concanavalin A (Con A)-stimulated alveolar macrophages (AMs) of rats. An inhibitor against protein kinase C (PKC) 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) suppressed a large part of this vitamin E-related effect, but a calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) did not inhibit the increase of active oxygen formation by vitamin E treatment. These results suggest that the activation of PKC presumably relates to the enhancing effect of vitamin E on active oxygen formation in Con A-stimulated AMs.
Biochem Mol Biol Int 1993 Oct
PMID:A mechanism of vitamin E-enhanced active oxygen formation in concanavalin A-stimulated alveolar macrophage. 827 16

In rat Sertoli cells, linoleate addition modified cell membrane fatty acid composition and changes depended on linoleate concentrations. In presence of the lowest 18:2 n-6 concentrations (2.5 and 7.5 microM), decrease in proteoglycan synthesis paralleled increase in n-6 linoleate-derived metabolites. At high concentration (21 microM), linoleate accumulated in membranes and level of n-6 linoleate-derived metabolites returned to basal value, without change in proteoglycan synthesis. Linoleate modified proteoglycan distribution in Sertoli cells by an increase in peripheral proteoglycans and a concomitant decrease in medium proteoglycans. Vitamin E (100 microM) did not alter fatty acid composition in control and linoleate-treated cells, but enhanced proteoglycan production. Furthermore, this agent counteracted linoleate-induced modifications in proteoglycan cell distribution.
Biochem Mol Biol Int 1993 Oct
PMID:Synthesis and distribution of rat Sertoli cell proteoglycans are modulated by linoleate and vitamin E. 827 18


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