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1.
The Safety of Adjuvanted Vaccines Revisited: Vaccine-Induced Narcolepsy.
Ahmed, SS, Montomoli, E, Pasini, FL, Steinman, L
The Israel Medical Association journal : IMAJ. 2016;(3-4):216-20
Abstract
Despite the very high benefit-to-risk ratio of vaccines, the fear of negative side effects has discouraged many people from getting vaccinated, resulting in the reemergence of previously controlled diseases such as measles, pertussis and diphtheria. This fear has been amplified more recently by multiple epidemiologic studies that confirmed the link of an AS03-adjuvanted pandemic influenza vaccine (Pandemrix, GlaxoSmithKline Biologicals, Germany) used in Europe during the 2009 H1N1 influenza pandemic [A(H1N1) pdm09] with the development of narcolepsy, a chronic sleep disorder, in children and adolescents. However, public misperceptions of what adjuvants are and why they are used in vaccines has created in some individuals a closed "black box" attitude towards all vaccines. The focus of this review article is to revisit this "black box" using the example of narcolepsy associated with the European AS03-adjuvanted pandemic influenza vaccine.
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2.
Vitamin E concentration in human milk and associated factors: a literature review.
Lima, MS, Dimenstein, R, Ribeiro, KD
Jornal de pediatria. 2014;(5):440-8
Abstract
OBJECTIVE To systematize information about vitamin E concentration in human milk and the variables associated with this composition in order to find possible causes of deficiency, supporting strategies to prevent it in postpartum women and infants. SOURCE Studies published between 2004 and 2014 that assayed alpha-tocopherol in human milk of healthy women by high performance liquid chromatography were evaluated. The keywords used were "vitamin E", "alpha-tocopherol", "milk, human", "lactation", and equivalents in Portuguese, in the BIREME, CAPES, PubMed, SciELO, ISI Web of Knowledge, HighWire Press, Ingenta, and Brazilian Digital Library of Theses and Dissertations databases. SUMMARY OF THE FINDINGS Of the 41 publications found on the subject, 25 whose full text was available and met the inclusion criteria were selected. The alpha-tocopherol concentrations found in milk were similar in most populations studied. The variable phase of lactation was shown to influence vitamin E content in milk, which is reduced until the mature milk appears. Maternal variables parity, anthropometric nutritional status, socioeconomic status, and habitual dietary intake did not appear to affect the alpha-tocopherol levels in milk. However, the influence of the variables maternal age, gestational age, biochemical nutritional status in alpha-tocopherol, and maternal supplementation with vitamin E had conflicting results in the literature. CONCLUSION Alpha-tocopherol concentration in milk decreases during lactation, until the mature milk appears. To confirm the influence of some maternal and child variables on milk vitamin E content, further studies with adequate design are needed.
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3.
The mechanism of photoinhibition in vivo: re-evaluation of the roles of catalase, α-tocopherol, non-photochemical quenching, and electron transport.
Murata, N, Allakhverdiev, SI, Nishiyama, Y
Biochimica et biophysica acta. 2012;(8):1127-33
Abstract
Photoinhibition of photosystem II (PSII) occurs when the rate of light-induced inactivation (photodamage) of PSII exceeds the rate of repair of the photodamaged PSII. For the quantitative analysis of the mechanism of photoinhibition of PSII, it is essential to monitor the rate of photodamage and the rate of repair separately and, also, to examine the respective effects of various perturbations on the two processes. This strategy has allowed the re-evaluation of the results of previous studies of photoinhibition and has provided insight into the roles of factors and mechanisms that protect PSII from photoinhibition, such as catalases and peroxidases, which are efficient scavengers of H(2)O(2); α-tocopherol, which is an efficient scavenger of singlet oxygen; non-photochemical quenching, which dissipates excess light energy that has been absorbed by PSII; and the cyclic and non-cyclic transport of electrons. Early studies of photoinhibition suggested that all of these factors and mechanisms protect PSII against photodamage. However, re-evaluation by the strategy mentioned above has indicated that, rather than protecting PSII from photodamage, they stimulate protein synthesis, with resultant repair of PSII and mitigation of photoinhibition. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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4.
Dynamics of lipid peroxidation and antioxidion of alpha-tocopherol in membranes.
Fukuzawa, K
Journal of nutritional science and vitaminology. 2008;(4):273-85
Abstract
The dynamics of initiation and inhibition of lipid peroxidation by alpha-tocopherol (alpha-Toc) in membranes were investigated under biological conditions using phosphatidylcholine liposomes. First, I examined how superoxide generated in the bulk water phase is able to induce lipid peroxidation in the inner hydrophobic region of the membrane. Second, I studied the localization of the antioxidant OH group of alpha-Toc in membranes and its lipid radical-trapping dynamics. Third, I investigated how alpha-Toc that is oxidized during radical trapping in membranes is recycled by ascorbic acid (AsA) in the bulk water phase. Finally, I studied the deactivation by alpha-Toc of singlet oxygen ((1)O(2)), which was generated by photoirradiation at the membrane surface, in the hydrophobic membrane inner region, and in bulk water, and measured the (1)O(2) deactivating rate constant of alpha-Toc in membranes considering: the concentration and mobility of alpha-Toc molecule in membranes, especially those of its active OH moiety located at the membrane domains, such as the membrane surface polar zone, inner hydrogen belt, and hydrophobic core, and the dielectric constant reflecting the reactivity of the OH moiety and (1)O(2) in the membrane domains where they interact.
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5.
So many options but one choice: the human body prefers alpha-tocopherol. A matter of stereochemistry.
Manolescu, B, Atanasiu, V, Cercasov, C, Stoian, I, Oprea, E, Buşu, C
Journal of medicine and life. 2008;(4):376-82
Abstract
alpha-Tocopherol belongs to the group of vitamin E vitamers. Recent years findings indicate that alpha-tocopherol is more than just a simple fat-soluble anti-oxidant as it was found that it can also regulate gene expression. From all vitamin E vitamers human body preferentially retains alpha-tocopherol, but the reasons for this preference are still elusive. Different studies indicated that human body, through the action of two hepatic proteins, alpha-tocopherol transfer protein (alpha-TTP) and cytochrome P450 4F2 (CYP4F2), is able to make subtle structural differences between different vitamin E forms. This is an example of stereochemistry used as a discrimination factor between molecules with different biological activities.