bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biological functions of carotenoids ‐ diversity and evolution
Authors: Vershinin Alexander 
Published: December 2008

AbstractCarotenoids first emerged in archaebacteria as lipids reinforcing cell membranes. To serve this function their long molecules have extremely rigid backbone due to the linear chain of usually 10 to 11 conjugated C=C bonds in trans‐configuration — the length corresponding the thickness of hydrophobic zone of membrane which they penetrate as “molecular rivets”. Carotenoids retain their membrane‐reinforcing function in some fungi and animals.The general structure of carotenoid molecule, originally having evolved for mechanical functions in membranes, possess a number of other properties that were later used for independent functions. The most striking fact is that these properties proved to fit some new functions to perfection.— The polyene chain of 9—11 double bonds absorbs light precisely in the gap of chlorophyll absorption — function as accessory light‐harvesting pigments in all plants;— Unique arrangement of electronic levels owing to the by polyene chain structure makes carotenoids the only natural compounds capable of excitation energy transfer both (i) from carotenoid excited state to chlorophyll in the light‐harvesting complex and (ii) from triplet chlorophyll or singlet oxygen to carotenoid in photosynthetic reaction centers — protection of RC from photodamage.The linear system of conjugated C=C bonds provides high reducing potential of carotenoid molecules making them potent antioxidants in lipid formations. Still, there is a lack of evidence of the chemical antioxidant function of carotenoids, especially in higher organisms; most data demonstrate an antioxidant ability rather than a function.Carotenoids have many other independent biological functions, including: specific coloration patterns in plants and animals, screening from excessive light and spectral filtering, defense of egg proteins from proteases in some invertebrates; the direct carotenoid derivative — retinal — acts as visual pigment in all animals and as chromophore in bacteriorhodopsin photosynthesis, retinoic acid in animals and abscisic acid in plants serve as hormones. All these functions utilize various properties (mechanical, electronic, stereospecific) of a single structure evolved in bacteria for a single membrane‐reinforcing function, thus demonstrating an example of pure evolutionary preadaptation.One of the practical conclusions that can be reached by reviewing uniquely diverse properties and functions of carotenoids is that, when considering possible mechanisms of their effects in organisms (e.g., anticarcinogenic action), all their functional traits should be taken into account.
Oxidative stress in hemodialysis patients treated with a dialysis membrane which has alpha‐tocopherol bonded to its surface
Authors: Sommerburg O. , Sostmann K. , Grune T. , Ehrich J. H. H. 
Published: December 2008

AbstractBackground: MDA, a major product of LPO, was shown to be increased in plasma of patients with end‐stage renal failure (ESRF) undergoing hemodialysis (HD). Elevated oxidative stress in ESRF patients is a result of multiple pathogenetic factors. HD treatment has been shown to be one important cause of accelerated radical generation. The aim of our study was to examine whether treatment with a dialysis membrane which has alpha‐tocopherol hydrophobically bonded to its surface (Excebrane by Terumo, Japan) can decrease oxidative stress due to HD.Methods: 10 ESRF patients undergoing HD three times weekly were examined. First, analysis was done when patients were still dialysed with the membranes used before the study. Thereafter, samples were taken when patients were dialysed first time with the Excebrane membrane, and six weeks after Excebrane treatment. Samples were collected always before and after HD session. A method with HPLC‐separation and flourimetric detection was used to measure plasma concentration of MDA.Results: After HD with the regularly used membranes MDA was found significantly increased (before HD 1.92 [1.81—2.02]μM (median and interquartile ranges) vs. after HD 2.26 [2.02—2.60]μM, p<0.05) suggesting that MDA was produced during HD. The first time Excebrane was used MDA was decreased significantly (before HD 2.04 [1.95—2.88]μM vs. after HD 1.35 [1.19—1.92]μM, p<0.05). After six weeks of Excebrane treatment, plasma MDA did not change significantly during HD (before HD 2.01 [1.69—2.62]μM vs. after HD 1.95 [1.42—2.20]μM).Conclusion: Oxidative stress due to HD might be significantly decreased by the Excebrane membrane. However, after six weeks of treatment with Excebrane no effect was seen on the initial plasma concentration of MDA compared to the time before.
Redox regulation of TNF signaling
Authors: Goossens Vera , Vos Kurt De , Vercammen Dominique , Steemans Margino , Vancompernolle Katia , Fiers Walter , Vandenabeele Peter , Grooten Johan 
Published: December 2008

AbstractTNF is produced during inflammation and induces, among other activities, cell death in sensitive tumour cells. We previously reported an increased generation of ROS in TNF‐treated L929 fibrosarcoma cells prior to cell death. These ROS are of mitochondrial origin and participate in the cell death process. Presently, we focus on the identification of parameters that control ROS production and subsequent cytotoxicity. From the cytotoxic properties and susceptibility to scavenging of TNF‐induced ROS as compared to pro‐oxidant‐induced ROS we conclude that TNF‐mediated ROS generation and their lethal action are confined to the inner mitochondrial membrane. Oxidative substrates, electron‐transport inhibitors, glutathione and thiol‐reactive agents but also caspase inhibitors modulate TNF‐induced ROS production and imply the existence of a negative regulator of ROS production. Inactivation of this regulator by a TNF‐induced reduction of NAD(P)H levels and/or formation of intraprotein disulfides would be responsible for ROS generation.
Changes in several functions of murine peritoneal macrophages by N‐acetylcysteine and thioproline ingestion. Comparative effect between two strains of mice
Authors: Blanco B. , Ferrández M. D. , Correa R. , Del Rio M. , Guaza C. , Hernanz A. , De La Fuente M. 
Published: December 2008

AbstractThe administration of the thiol compounds, N‐acetylcysteine (NAC) and in particular thioproline (thiazolidine‐4‐carboxylic acid) at 0.1% w/w concentration in the diet, improves lymphocyte functions in old female Swiss mice, as has been shown in our previous studies. In the present work, adult mice from two different strains, namely BALB/c (an inbred strain) and OF1‐Swiss (noninbred strain), were fed a diet supplemented with the above dose of each thiol compound jointly for five weeks. At 28 weeks of age, peritoneal cell suspensions were obtained and different steps of the phagocytic process, the most representative activity of macrophages, as well as interleukin‐1β (IL‐1β) production, were studied. Thus, adherence to substrate, mobility directed to a chemoattractant gradient (chemotaxis), ingestion of inert particles and superoxide anion production were analysed. The results show that diet supplementation with NAC plus thioproline increased all macrophage functions studied with the exception of superoxide anion production, which was decreased. These effects were more evident in macrophages from Swiss mice, whereas in BALB/c mice the stimulation of phagocytosis and IL‐1β production was lower and no differences were seen after treatment in adherence and superoxide anion production. These data suggest that immune function can be improved in adult mice by administration of the above thiol compounds, especially in the noninbred strain of OF1‐Swiss mice.
N‐Acetyl‐cysteine inhibition of encephalomyelitis Theiler's virus‐induced nitric oxide and tumour necrosis factor‐α production by murine astrocyte cultures
Authors: Molina‐Holgado F. , Hernanz A. , De La Fuente M. , Guaza C. 
Published: December 2008

AbstractThe pathological mechanisms that cause central nervous system (CNS) dysfunction in most neurological diseases are not well established. Theiler's murine encephalomyelitis virus (TMEV) is known to interact with cells of the CNS and its intracerebral inoculation to susceptible mice strains causes neurological disorders resembling multiple sclerosis (MS). In this study, we reported that primary astrocyte cultures from SJL/J susceptible mice when infected with TMEV released important amounts of nitrites (NO2−) to the culture medium, as measured in the supernatants 24 hours after infection. In addition, we observed an increment in the production of tumour necrosis factor alpha (TNF‐α) by susceptible SJL/J strain derived astrocytes infected with TMEV. The treatment with the thiolic antioxidant N‐acetyl‐cysteine partially suppressed the virus‐stimulated production of nitric oxide and TNF‐α, in a dose response fashion. These results indicate that during viral infection astrocytes are an important cellular source of nitric oxide and TNF‐α, substances which play important roles during CNS inflammatory events. The effects of the antioxidant N‐acetyl‐cysteine, modulating the production of the above compounds by TMEV‐infected astrocytes may be a significant factor in preventing CNS demyelination.
Gastrointestinal glutathione peroxidase
Authors: Wingler Kirstin , Brigelius‐Flohé Regina 
Published: December 2008

AbstractThe gastrointestinal glutathione peroxidase (GI‐GPx) is the fourth member of the GPx family. In rodents, it is exclusively expressed in the gastrointestinal tract, in humans also in liver. It has, therefore, been discussed to function as a primary barrier against the absorption of ingested hydroperoxides. A vital function of GI‐GPx can be deduced from the unusual stability of its mRNA under selenium‐limiting conditions, the presence of low amounts of GI‐GPx protein in selenium deficiency where cGPx is absent, and the fast reappearance of the GI‐GPx protein upon refeeding of cultured cells with selenium compared to the slower reappearance of cGPx protein. Furthermore, the Secis efficiency of GI‐GPx is low when compared to cGPx and PHGPx. It is, however, almost independent of the selenium status of the cells tested. All these characteristics rank GI‐GPx high in the hierarchy of selenoproteins and point to a role of GI‐GPx which might be more crucial than that of cGPx, at least in the gastrointestinal system.
Various functions of selenols and thiols in anaerobic Gram‐positive, amino acids‐utilizing bacteria
Authors: Andreesen Jan R. , Wagner Matthias , Sonntag Denise , Kohlstock Martin , Harms Claudia , Gursinsky Torsten , Jäge Jana , Parther Tina , Kabisch Ute , Gräntzdöffer Andrea , Pich Andreas , Söhling Brigitte 
Published: December 2008

AbstractElectron transfer reactions for the reduction of glycine in Eubacterium acidaminophilum involve many selenocysteine (U)‐ and thiol‐containing proteins, as shown by biochemical and molecular analysis. These include an unusual thioredoxin system (‐CXXC‐), protein A (‐CXXU‐) and the substrate‐specific protein B of glycine reductase (‐UXXCXXC‐). Most probably a selenoether is formed at protein B by splitting the C‐N‐bond after binding of the substrate. The carboxymethyl group is then transferred to the selenocysteine of protein A containing a conserved motif. The latter protein acts as a carbon and electron donor by giving rise to a protein C‐bound acetyl‐thioester and a mixed selenide‐sulfide bond at protein A that will be reduced by the thioredoxin system. The dithiothreitol‐dependent D‐proline reductase of Clostridium sticklandii exhibits many similarities to protein B of glycine reductase including the motif containing selenocysteine. In both cases proprotein processing at a cysteine residue gives rise to a blocked N‐terminus, most probably a pyruvoyl group. Formate dehydrogenase and some other proteins from E. acidaminophilum contain selenocysteine, e.g., a 22 kDa protein showing an extensive homology to peroxiredoxins involved in the detoxification of peroxides.
Molecular and cellular mechanisms of transepithelial iodide transport in the thyroid
Authors: Nilsson Mikael 
Published: December 2008

AbstractThyroid hormone is an essential regulator of developmental growth and metabolism in vertebrates. Iodine is a necessary constituent of thyroid hormone. Due to the scarcity and uneven distribution of iodine on the Earth's crust, the structure of the thyroid gland is adjusted to collect and store this element in order to secure a continuous supply of thyroid hormone throughout life. Still, disease resulting from hypothyroidism due to iodine deficiency is a global health problem, illustrating the great biological significance that iodine saving mechanisms have evolved. Iodide is accumulated together with prohormone (thyroglobulin) in the lumen of the thyroid follicles. The rate‐limiting step of this transport is the sodium/iodide symporter located in the basolateral plasma membrane of the thyroid follicular cells. Iodide is also transferred across the apical plasma membrane into the lumen where hormonogenesis takes place. In this review, recent progress in the understanding of transepithelial iodide transport in the thyroid is summarized.
Folate status and neural tube defects
Authors: Molloy Anne M. , Mills James L. , Kirke Peadar N. , Weir Donald G. , Scott John M. 
Published: December 2008

AbstractPericonceptional folic acid supplementation prevents approximately 70% of neural tube defects (NTDs). While most women carrying affected fetuses do not have deficient blood folate levels, the risk of having an NTD affected child is inversely correlated with pregnancy red cell folate levels. Current research is focused on the discovery of genetic abnormalities in folate related enzymes which might explain the role of folate in NTD prevention. The first candidate gene to emerge was the C677T variant of 5,10‐methylenetetrahydrofolate reductase. Normal subjects who are homozygous for the mutation (TT) have red cell folate status some 20% lower than expected. It is now established that the prevalence of the TT genotype is significantly higher among spina bifida cases and their parents. Nevertheless, our studies show that the variant does not account for the reduced blood folate levels in many NTD affected mothers. We conclude that low maternal folate status may in itself be the most important risk factor for NTDs and that food fortification may be the only population strategy of benefit in the effort to eliminate NTDs.
Proposed standard for human blood vitamin B1 value using HPLC
Authors: Itokawa Y. , Hashizume N. , Asano M. , Igarashi O. , Mino M. , Ihara H. , Ishiwata Y. , Kadowaki H. , Kubota N. , Okazaki M. , Sueki K. , Ishida Y. , Gorin M. , Sato T. , Sayama Y. , Shimomura K. , Takano H. , Nakamura T. , Hanawa M. , Niimura H. , Morio T. , Chibata I. , Okuda K. 
Published: December 2008

AbstractStandard reference ranges for all laboratory test values are mandatory. This study was designed to establish a reference range for blood vitamin B1 levels, since the normal range has not been determined in the Japanese population. We founded the Japan Committee for Vitamin Laboratory Standards, which was incorporated with the Vitamin Society of Japan and the Japanese Society of Nutrition and Food Science. We standardized whole blood vitamin B1 levels using three HPLC techniques (post‐column reverse‐phase HPLC, pre‐column reverse‐phase HPLC, and precolumn GP‐HPLC). The reference range was obtained in 54 volunteers administered a 1,800 kcal diet with 2 mg of vitamin B1 (1.74 mg measured) daily to avoid marginal vitamin B1 deficiency in the population. The range for each assay was 26—47, 28—51, and 28—56 ng/ml, respectively. Our data suggest that 26—28 ng/ml is the lower limit of normal for whole blood vitamin B1, but further studies in a larger population are needed in order to obtain more definitive results.
Pyruvate dehydrogenase kinase 4 mRNA is increased in the hypertrophied ventricles of carnitine‐deficient juvenile visceral steatosis (JVS) mice
Authors: Horiuchi Masahisa , Kobayashi Keiko , Masuda Mina , Terazono Hiroki , Saheki Takeyori 
Published: December 2008

AbstractWe isolated a mouse homologue cDNA of pyruvate dehydrogenase (PDH) kinase 4 (PDK4) with differential mRNA display as an up‐regulated gene in the hypertrophied ventricles of juvenile visceral steatosis (JVS) mice with systemic carnitine deficiency. The PDK4 mRNA level was 5 times higher in JVS mice than in control mice under fed conditions. After 24 h starvation, this level increased to 20 times in JVS and 7 times in control, compared with the control fed level. On the other hand, carnitine administration reduced the high level of PDK4 mRNA in JVS mice to the control fed level. In control mice, the change in PDK4 mRNA was inversely correlated with the change in PDH activity. In JVS mice, however, the PDK4 mRNA level was not always correlated with the active‐form PDH level.
Morphological and biochemical responses of Bacillus subtilis to selenite stress
Authors: Garbisu Carlos , Carlson Donald , Adamkiewicz Mike , Yee Boihon C. , Wong Joshua H. , Resto Edgar , Leighton Terrance , Buchanan Bob B. 
Published: December 2008

AbstractWhen introduced into a chemically defined minimal medium supplemented with 1 mM sodium selenite (79 ppm Se°), Bacillus subtilis was found to undergo a series of morphological and biochemical adaptations. The morphological changes included the formation of “round bodies” associated with the detoxification of selenite to elemental selenium. Round bodies observed transiently were not apparent during balanced growth of cells adapted previously to selenite‐containing medium. Under balanced growth conditions, cell structures similar to “round bodies”, could be produced by treating cells with lysozyme. The selenite‐induced structural alterations in cells were accompanied by an increase in the content of thioredoxin and the associated enzyme, NADP‐thioredoxin reductase. The results suggest that the biovalence transformation of high levels of selenite may involve a dithiol system.
Modulation of murine macrophage function by N‐acetylcysteine in a model of endotoxic shock
Authors: Víctor V. M. , Guayerbas N. , Garrote D. , Del Río M. , De La Fuente M. 
Published: December 2008

AbstractIn previous studies we have observed changes in several functions of peritoneal macrophages from BALB/c mice with irreversible endotoxic shock caused by intraperitoneal injection of E. coli lipopolysaccharide (LPS) (100 mg/kg), which were associated with a high production of superoxide anion. Since antioxidants, such as N‐acetylcysteine (NAC), are free radical scavengers that improve the immune response, in the present work we have studied different functions of peritoneal macrophages from BALB/c mice suffering the endotoxic shock above indicated and administered N‐acetylcysteine (150 mg/kg i.p.) at 30 minutes after LPS injection. In the peritoneal macrophages obtained at 2, 4, 12 and 24 h after LPS injection, the following functions were studied: adherence to substrate, mobility, ingestion of particles, and production of superoxide anion and tumour necrosis factor (TNFα). The increase in adherence, ingestion and superoxide anion and TNFα production shown by macrophages from animals with endotoxic shock was counteracted by NAC injection. Moreover, the survival time of mice with endotoxic shock was increased in the presence of NAC. These data suggest that NAC, administered intraperitoneally, may be useful for the treatment of irreversible endotoxic shock by modulation of the function of macrophages with decreased superoxide anion and TNFα production and concomitant increase of survival time.
An investigation into a possible relationship between vitamin D, parathyroid hormone, calcium and magnesium in a normally pigmented and an albino rural black population in the Northern Province of South Africa
Authors: Cornish Daryl A. , Maluleke Vusi , Mhlanga Thulani 
Published: December 2008

AbstractVitamin D levels are important in the management of patients with various disorders of calcium metabolism associated with rickets, osteomalacia, osteodystrophy osteoporosis and hypoparathyroidism. 82 albinos and 58 normally pigmented children resident at the Siloe School for the Visually Impaired were sampled. Blood samples of fasting subjects were collected over a two‐day period and analyzed for vitamin D, parathyroid hormone, plasma calcium and both plasma and red blood cell magnesium measurements. The height and weight of each subject was also recorded. The results are discussed in relation to the different skin pigmented groups, for specific age groups, sex and visual status. Statistical outliers were excluded from the results. It appears that the Albino group has significantly (p=0.06) higher vitamin D levels against the background of a similar dietary intake and similar exposure to sunlight/day length. Thus black children/subjects require a significantly higher intake of vitamin D to attain the same level as their Albino counterparts. In spite of significantly higher vit D levels, the other homeostatic control mechanisms were not altered (i.e., PTH levels are similar in both groups). This study supports the postulate that a dark complexion predisposes to sub‐optimal vit D status.
Inhibition of cathepsin activities by vitamin B6 derivatives
Authors: Matsui A. , Tsuzuki H. , Murata E. , Tada Y. , Asao T. , Katunuma N. 
Published: December 2008

AbstractWe found that pridoxal phosphate (PLP), a coenzyme form of vitamin B6, inhibited the activity of cathepsins B, K, S and L in vitro. Cathepsins activities in cultured splenocytes were suppressed by the addition of pridoxal (PL) or pridoxine (PI) in to the culture medium. A newly synthesized artificial vitamin B6 derivative, a pridoxal propionate derivative, CLIK‐164, showed selective inhibition of cathepsin O/K.
Is chromium a trace essential metal?
Authors: Stearns Diane M. 
Published: December 2008

AbstractIf chromium is an essential metal it must have a specific role in an enzyme or cofactor, and a deficiency should produce a disease or impairment of function. To date, no chromium‐containing glucose tolerance factor has been characterized, the purpose of the low‐molecular‐weight chromium‐binding protein is questionable, and no direct interaction between chromium and insulin has been found. Furthermore, chromium3+is treated like the toxic metals arsenic, cadmium, lead and mercury in animals. Chromium3+may be involved in chromium6+‐induced cancers because chromium6+is converted to chromium3+in vivo, and chromium3+is genotoxic and mutagenic. Although there is no direct evidence of chromium deficiencies in humans, dietary supplements exist to provide supraphysiological doses of absorbable chromium3+. Chromium3+may act clinically by interfering with iron absorption, decreasing the high iron stores that are linked to diabetes and heart disease. If so, this would make chromium3+a pharmacological agent, not an essential metal.