bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of the dystrobrevin binding protein 1 gene (DTNBP1) in a bipolar case–control study (BACCS)
Authors: Gaysina Darya , Cohen‐Woods Sarah , Chow Philip C. , Martucci Livia , Schosser Alexandra , Ball Harriet A. , Tozzi Federica , Perry Julia , Muglia Pierandrea , Craig Ian W. , McGuffin Peter , Farmer Anne
Published: December 2008

Recent studies suggest a degree of overlap in genetic susceptibility across the traditional categories of schizophrenia and bipolar disorder. There is some evidence for an association of the dystrobrevin binding protein 1 gene (DTNBP1) with schizophrenia, and, thus, this gene has also become a focus of further investigation in bipolar disorder (BD). The aim of our study is to explore the association of DTNBP1 with BD and with a sub phenotype, presence/absence of psychotic symptoms, in a sample of 515 patients with BD (ICD10/DSMIV) and 1,316 ethnically matched control subjects recruited from the UK. Seven DTNBP1 SNPs: rs2743852 (SNP C), rs760761 (P1320), rs1011313 (P1325), rs3213207 (P1635), rs2619539 (P1655), rs16876571 and rs17470454 were investigated using the SNPlex genotyping system and 1 SNP (rs2619522) genotypes were imputed. Association analyses were conducted in a sample of 452 cases and 956 controls. We found significant differences in genotypic and allelic frequencies of rs3213207 and rs760761 of DTNBP1 between bipolar patients and controls. We also showed a global haplotypic association and an association of a particular haplotype with BD. Our results are consistent with previous studies in term of a general association between DTNBP1 and bipolar disorder and provide additional evidence that a portion of the genotypic overlap between schizophrenia and bipolar affective disorder is attributable to this gene. © 2008 Wiley‐Liss, Inc.
Mutation screen and association analysis of the glucocorticoid receptor gene (NR3C1) in childhood‐onset mood disorders (COMD)
Authors: Mill J. , Wigg K. , Burcescu I. , Vetró Á. , Kiss E. , Kapornai K. , Tamás Z. , Baji I. , Gádoros J. , Kennedy J.L. , Kovacs M. , Barr C.L. ,   The International Consortium for Childhood‐Onset Mood Disorders
Published: December 2008

Depressive disorders are highly heterogeneous psychiatric disorders involving deficits to cognitive, psychomotor, and emotional processing. Considerable evidence links disruption to the hypothalamic–pituitary–adrenal (HPA) axis to the etiology of depression, with specific deficits reported in glucocorticoid receptor (GR)‐mediated negative feedback. Given the role of GR‐mediated negative feedback in mediating response to stress, and the clear link between stress and depression, it is plausible that polymorphisms in the GR gene (NR3C1) act to increase susceptibility. Maternal behavior in rats epigenetically alters a NGF1‐A transcription factor binding‐site in the promoter region of the GR gene, providing a mechanism by which environmental cues can regulate GR expression and thus response to stress. The analogous region of the human GR gene (NR3C1) has not been studied, but it is possible that polymorphisms in this region may alter the binding of transcription factors known to regulate GR expression. In this study, we have performed bioinformatic analyses on the promoter region of NR3C1 to identify conserved promoter sequences and predicted transcription factor binding sites. These regions were screened with denaturing high‐performance liquid chromatography (DHPLC) and direct re‐sequencing, and several novel polymorphic variants were identified. We genotyped nine polymorphisms across NR3C1 in a large sample of Hungarian nuclear families ascertained through affected probands with a diagnosis of childhood‐onset mood disorders (COMD). Single‐marker analysis provided little evidence for an association of this gene with COMD, but multi‐marker analysis across a region of high linkage disequilibrium revealed modest evidence for the biased transmission of several haplotypes. © 2008 Wiley‐Liss, Inc.
Production and perception of sex differences in vocalizations of Wied's black‐tufted‐ear marmosets (Callithrix kuhlii)
Authors: Smith Adam S. , Birnie Andrew K. , Lane Kent R. , French Jeffrey A.
Published: December 2008

Males and females from many species produce distinct acoustic variations of functionally identical call types. Social behavior may be primed by sex‐specific variation in acoustic features of calls. We present a series of acoustic analyses and playback experiments as methods for investigating this subject. Acoustic parameters of phee calls produced by Wied's black‐tufted‐ear marmosets (Callithrix kuhlii) were analyzed for sex differences. Discriminant function analyses showed that calls contained sufficient acoustic variation to predict the sex of the caller. Several frequency variables differed significantly between the sexes. Natural and synthesized calls were presented to male–female pairs. Calls elicited differential behavioral responses based on the sex of the caller. Marmosets became significantly more vigilant following the playback of male phee calls (both natural and synthetic) than following female phee calls. In a second playback experiment, synthesized calls were modified by independently manipulating three parameters that were known to differ between the sexes (low‐, peak‐, and end‐frequency). When end‐frequency‐modified calls were presented, responsiveness was differentiable by sex of caller but did not differ from responses to natural calls. This suggests that marmosets did not use end‐frequency to determine the sex of the caller. Manipulation of peak‐and low‐frequency parameters eliminated the discrete behavioral responses to male and female calls. Together, these parameters may be important features that encode for the sex‐specific signal. Recognition of sex by acoustic cues seems to be a multivariate process that depends on the congruency of acoustic features. Am. J. Primatol. 71:324–332, 2009. © 2008 Wiley‐Liss, Inc.
Identification of factors predicting clickthrough in Web searching using neural network analysis
Authors: Zhang Ying , Jansen Bernard J. , Spink Amanda
Published: December 2008

In this research, we aim to identify factors that significantly affect the clickthrough of Web searchers. Our underlying goal is determine more efficient methods to optimize the clickthrough rate. We devise a clickthrough metric for measuring customer satisfaction of search engine results using the number of links visited, number of queries a user submits, and rank of clicked links. We use a neural network to detect the significant influence of searching characteristics on future user clickthrough. Our results show that high occurrences of query reformulation, lengthy searching duration, longer query length, and the higher ranking of prior clicked links correlate positively with future clickthrough. We provide recommendations for leveraging these findings for improving the performance of search engine retrieval and result ranking, along with implications for search engine marketing.
Including prenatal diagnoses in birth defects monitoring: Experience of the Metropolitan Atlanta Congenital Defects Program
Authors: Cragan Janet D. , Gilboa Suzanne M.
Published: December 2008

BACKGROUND: Advances in prenatal diagnosis have led to changes in the management of pregnancies affected with birth defects. These changes pose unique challenges for birth defects monitoring programs which use hospital‐based sources. METHODS: In 1994, Metropolitan Atlanta Congenital Defects Program (MACDP) abstractors began to visit area perinatologists' offices to identify pregnancies diagnosed prenatally with fetal defects. These pregnancies were then linked with existing MACDP cases and the hospital deliveries abstracted. Those without a hospital delivery were included as having unknown outcomes. Prenatally diagnosed defects were classified as definite or possible based on the certainty of the prenatal description. For 1995–2004, we calculated minimum and maximum adjusted defect prevalences by adding definite prenatal defects, and definite plus possible prenatal defects, to the hospital‐based cases. RESULTS: We identified 1009 pregnancies with a prenatally diagnosed defect not ascertained from MACDP hospital sources. Including these increased the total defect prevalence from 28 per 1000 live births to a minimum of 29.94 (6.9% increase) and maximum of 30.14 (7.7% increase) per 1000. The minimum increase was greater than 50% for conjoined twins, triploidy, craniorachischisis, cystic hygroma, Klinefelter syndrome, anencephaly, Turner syndrome, and trisomies 13, 18 and 21 among mothers ≥35. CONCLUSIONS: These data reflect the variety of congenital abnormalities that can be detected prenatally and the importance of including prenatal diagnoses in birth defects monitoring data. Birth defects monitoring programs should assess individually the extent to which prenatal diagnosis can affect the accuracy and completeness of their data. Birth Defects Research (Part A), 2009. Published 2008 Wiley‐Liss, Inc.
A review of Donnai‐Barrow and facio‐oculo‐acoustico‐renal (DB/FOAR) syndrome: Clinical features and differential diagnosis
Authors: Pober Barbara R. , Longoni Mauro , Noonan Kristin M.
Published: December 2008

Mutations in the gene LRP2 have recently been identified as the cause of Donnai‐Barrow and Facio‐oculo‐acoustico‐renal (DB/FOAR) syndrome. More than two dozen cases, the first reported more than 30 years ago by Holmes, have been published. Summarizing available information, we highlight the cardinal features of the disorder found in ≥90% of published cases. These features include: agenesis of the corpus callosum, developmental delay, enlarged anterior fontanelle, high myopia, hypertelorism, proteinuria, and sensorineural hearing loss. Congenital diaphragmatic hernia and omphalocele are reported in only half of the patients. There is no evidence for genotype‐phenotype correlation, though the sample size is too small to preclude this with certainty. Although several conditions to consider in the differential diagnosis are highlighted, the diagnosis of DB/FOAR syndrome should not be difficult to establish as its constellation of findings is strikingly characteristic. Birth Defects Research (Part A), 2009. © 2008 Wiley‐Liss, Inc.
Whole plasma oxidation assay as a measure of lipoprotein oxidizability
Authors: Kontush Anatol , Spranger Torsten , Reich Axel , Djahansouzi Sirus , Karten Barbara , Braesen Jan Hinrich , Finckh Barbara , Kohlschütter Alfried , Beisiegel Ulrike
Published: December 2008

Lipoprotein oxidation induced in vitro in whole plasma is expected to be a more relevant model of the lipoprotein oxidation in the arterial wall than the in vitro oxidation of single isolated lipoproteins, e.g., low density lipoprotein (LDL). However, it is unclear, whether the oxidizability of whole plasma may serve as an adequate measure of the oxidizability of plasma lipoproteins. We measured the oxidizability of whole plasma diluted 150‐fold as an absorbance increase at 234 nm known to reflect the level of conjugated dienes in the samples. Plasma oxidation was induced by Cu(II), 2,2′‐azobis‐(2‐amidinopropane) hydrochloride (AAPH), lipoxygenase or myeloperoxidase+H2O2. Oxidizability of human plasma measured in the presence of Cu(II) was found to correlate with the oxidizability of LDL measured in the common Cu(II)‐based LDL oxidation assay. The plasma oxidizability also correlated positively with plasma oxidizable fatty acid and negatively with plasma antioxidant content. Supplementation of human plasma with different antioxidants (albumin, urate, ascorbate, bilirubin, α‐tocopherol and ubiquinol‐10) in vitro decreased its oxidizability. Supplementation of Watanabe heritable hyperlipidaemic rabbits with different antioxidants (vitamin E, ubiquinone‐10, probucol, carvedilol) in vivo lowered the oxidizability of rabbit plasma in comparison with rabbits fed standard diet. When plasma from hyperlipidaemic patients with or without coronary heart disease and from age‐matched healthy controls was studied, the plasma oxidizability was found to be highest in the patients with coronary heart disease and lowest in the controls. Taken together, these data indicate that the plasma oxidation assay (i) provides information similar to that obtained using the common LDL oxidation assay, (ii) upgrades the latter, taking into account the effect of hydrophilic antioxidants on lipoprotein oxidation and characterizing the oxidizability of all plasma lipoproteins, and (iii) offers important practical advantages, such as fast and simple sample processing, low amount of plasma required and avoidance of artefactual oxidation during lipoprotein isolation. We propose the measurement of plasma oxidizability at 234 nm as an adequate practical index of the oxidizability of plasma lipoproteins.
The role of oxidative stress in the long‐term glycation of LDL
Authors: Menzel E. J. , Sobal G. , Staudinger A.
Published: December 2008

Advanced glycation is a major pathway for the posttranslational modification of plasma and tissue proteins. The initiating reaction is the nonenzymatic addition of sugars such as glucose to the primary amino groups of proteins, i.e., mainly to lysine residues. These ‘early’ Schiff base and Amadori products then undergo a series of inter‐ and intramolecular rearrangements to produce the ‘late’ products termed advanced glycation end products (AGEs). Incubation of LDL with glucose or glucose‐6‐phosphate produces AGE moieties on both the lipid and apolipoprotein B components. In addition, we tried to generate AGE‐LDL by reaction with AGE‐peptides (<10 kD) obtained by enzymatic digestion of long‐term glycated fibronectin as a model for connective tissue AGE‐peptides. AGE‐formation can be assessed by monitoring of fluorescence (370/440 nm) which is easily differentiated from the much lower autofluorescence of oxidized low density lipoproteins (oxLDL). Alternatively, AGE formation was detected by an AGE‐specific ELISA using antibodies elicited in rabbits against bovine AGE‐RNAse. In the present study we investigated the influence of oxidative stress on the long‐term glycation of LDL and the modulation of LDL‐oxidation by AGE‐modification. We observed (a) that the rate of AGE formation is reduced by BHT/EDTA both on LDL and serum albumin (glycation vs.glycoxidation), (b) long‐term glycated LDL is more readily oxidized than unglycated LDL, (c) oxLDL is more prone to AGE‐modification, (d) AGE‐modification of LDL strongly alters its epitope spectrum and (e) that aminoguanidine at higher concentrations (1–10 mM) inhibits copper‐catalyzed LDL oxidation in the way of a classical antioxidant.
Interactions between macrophages and oxidized low density lipoprotein in the presence of type I collagen
Authors: Chen Qi , Wei Enhui , Chen Xiuying , Wang Nan , Jürgens Günther
Published: December 2008

In order to investigate the influence of collagen on the interactions between macrophages and oxidatively modified low density lipoprotein (ox‐LDL), type I collagen was isolated from rat tail tendon and prepared as a gel. The binding of 125I‐ox‐LDL, 125I‐malondialdehyde (MDA)‐LDL and 125I‐acetyl‐LDL to collagen was higher but the binding of 125I‐4‐hydroxynonenal (HNE)‐LDL was lower than that of native 125I‐LDL. When mouse peritoneal macrophages were cultivated on this collagen gel, most of the modified LDL was bound to the collagen gel rather than taken up by macrophages. The amount of modified 125I‐LDL degraded by the macrophages decreased in the presence of the collagen gel. In the absence of gel a similar degree of reduction in degradation of modified 125I‐LDL by macrophages was obtained when the cells were treated with cytochalasin D, an inhibitor of non‐specific phagocytosis. However, the treatment of the macrophages cultivated on the collagen gel with cytochalasin D did not influence the degradation of 125I‐ox‐LDL and 125I‐HNE‐LDL. These results suggest that the uptake of ox‐LDL by macrophages grown on collagen gels is primarily mediated via the scavenger receptors pathway, whereas in the absence of collagen also other mechanisms of uptake are operating.
Pathways for oxidation of low density lipoprotein by myeloperoxidase: tyrosyl radical, reactive aldehydes, hypochlorous acid and molecular chlorine
Authors: Heinecke Jay W.
Published: December 2008

Many lines of evidence implicate oxidation of low density lipoprotein (LDL) in the pathogenesis of atherosclerosis, a chronic inflammatory disease. The physiologically relevant mechanisms have not been identified, but phagocytic white cells may play an important role because macrophage‐rich lesions characterize the disorder.

Recent studies have shown that myeloperoxidase, a heme enzyme secreted only by phagocytes, is present in human atherosclerotic tissue. The enzyme is a potent catalyst of LDL oxidation in vitro, it co‐localizes with macrophages in lesions, and it generates products that are detectable in atherosclerotic plaque. These findings suggest that myeloperoxidase may promote LDL oxidation in the artery wall.

This article reviews the enzyme's ability to generate a range of oxidants, including tyrosyl radical, reactive aldehydes, hypochlorous acid and molecular chlorine. These products have the potential to damage host molecules as well as microbes, suggesting a mechanism that may contribute to atherosclerotic vascular disease.
The mechanism of the hypochlorite‐induced lipid peroxidation
Authors: Panasenko Oleg M.
Published: December 2008

The article reviews data related to the role of exogenic hypochlorite (HOCl/OCl−) and hypochlorite produced by myeloperoxidase catalysis in initiation of lipid peroxidation (LPO) in phospholipid membranes and human blood lipoproteins (LP). It has been shown that HOCl/OCl− promotes free radical lipid oxidation in liposomes and LP that is followed by the formation of LPO products: hydroperoxides, conjugated dienes, TBARS, and fluorescent products. Water soluble reactive substances •O2−, H2O2, Fe2+) which can be present in the reaction mixture as a dopant are not the source of free radicals and do not participate in HOCl/OCl−‐induced LPO at the initiation step. The main reaction of HOCl/OCl− with unsaturated lipid is probably the generation of chlorohydrins. However, this reaction is not accompanied by generation of free radicals and LPO. HOCl/OCl− reacts efficiently with TBARS of aldehydic nature. It is likely that the reaction proceeds without the participation of free radicals. Among the compounds of a peroxide nature (hydro‐, dialkyl‐, diacyl‐, alkyl‐acyl‐peroxide groups and epoxides) only hydroperoxides react with HOCl/OCl−. This reaction is accompanied by the production of free radicals (but not singlet oxygen), probably alkoxyl radicals, which may play a role in the initiation of HOCl/OCl−‐induced LPO.
Farnesyl: proteintransferase inhibitors as agents to inhibit tumor growth
Authors: Omer Ch. A. , Anthony N. J. , Buser‐Doepner C. A. , Burkhardt A. L. , Desolms S. J. , Dinsmore Ch. J. , Gibbs J. B. , Hartman G. D. , Koblan K. S. , Lobell R. B. , Oliff A. , Williams T. M. , Kohl N. E.
Published: December 2008

Ras, a signal‐transducing protein involved in mediating growth factor‐stimulated proliferation, is mutationally activated in over 30% of human tumors. To be functional Ras must bind to the inner surface of the plasma membrane, with post‐translational lipid modifications being necessary for this localization. The essential, first modification of Ras is farnesylation catalyzed by the enzyme farnesyl: proteintransferase (FPTase). Inhibitors of FPTase (FTIs) are currently being tested to determine if they are capable of tumor growth inhibition. Here we describe our efforts, along with those of other groups, in testing the biological and biochemical effects of FTIs.
Molecular basis of α‐tocopherol control of smooth muscle cell proliferation
Authors: Azzi Angelo , Aratri Elisabetta , Boscoboinik Daniel , Clément Sophie , Özer Nesrin K. , Ricciarelli Roberta , Spycher Stefan
Published: December 2008

Rat and human vascular smooth muscle cell proliferation is specifically sensitive to α‐tocopherol, but not β‐tocopherol. The former, but not the latter, is capable of limiting proliferation and inhibiting protein kinase C activity in a dose‐dependent manner. The phenomenon occurs at concentrations in the range 10–50 μM. β‐tocopherol addition together with α‐tocopherol, prevents both cell growth and protein kinase C inhibition. α‐tocopherol increases de novo synthesis of protein kinase C molecules. The enzyme specific activity, however, is diminished, due to a decreased phosphorylation of protein kinase C, occurring in the presence of α‐tocopherol. Experiments with protein kinase C isoform‐specific inhibitors and precipitating antibodies show that the only isoform affected by α‐tocopherol is protein kinase C‐α. The effect of α‐tocopherol is prevented by okadaic acid indicating a phosphatase of the PP2A type as responsible for protein kinase C‐α dephosphorylation produced in the presence of α‐tocopherol. At a gene level α‐tocopherol but not β‐tocopherol induces a transient activation of α‐tropomyosin gene transcription and protein expression. It is proposed that, by inhibiting protein kinase C activity via an activation of a phosphatase PP2A, α‐tocopherol controls smooth muscle cell proliferation through changes in gene expression.
d‐α‐tocopherol treatment prevents glomerular dysfunctions in diabetic rats through inhibition of protein kinase C‐diacylglycerol pathway
Authors: Koya Daisuke , Haneda Masakazu , Kikkawa Ryuichi , King George L.
Published: December 2008

Since diabetes now accounts for 35% of all new cases of end‐stage renal disease in the United States, it is really important to prevent the onset of diabetic nephropathy. Activation of protein kinase C (PKC) is implicated to be one of the causal factors in the development of renal dysfunctions in diabetes. In this study, we have demonstrated that total diacylglycerol (DAG) contents and PKC activity in glomeruli were significantly increased in diabetic rats as compared to control rats, but intraperitoneal injection of d‐α‐tocopherol prevented these biochemical abnormalities in parallel with normalization of glomerular dysfunction such as increased glomerular filtration rate (GFR) in diabetic rats. Albuminuria in diabetic rats was also significantly increased as compared to control rats, whereas d‐α‐tocopherol treatment again ameriolated increased albuminuria in parallel with the inhibition of glomerular PKC activation by diabetes. Moreover, we have observed that the activity of DAG kinase, which metabolizes DAG to phosphatidic acid and acts as an attenuator for the DAG‐PKC pathway, was enchanced by d‐α‐tocopherol treatment. These results suggest that the increase in the DAG‐PKC pathway might play an important role for the development of glomerular dysfunctions in diabetes and d‐α‐tocopherol treatment could be helpful in diabetic nephropathy.
Developmental changes in the expression of α‐tocopherol transfer protein during the neonatal period of rat
Authors: Tamai Hiroshi , Kim Han‐Suk , Arai Hiroyuki , Inoue Keizo , Mino Makoto
Published: December 2008

It is well known that the cellular concentration of α‐tocopherol (α‐toc) is about 10‐fold greater than that of γtocopherol (γtoc) despite the ingestion of a large amount of γtoc in the diet. Recently, this discrimination of tocopherol is considered to be attributed to α‐tocopherol transfer protein (α‐TTP) which binds to α‐toc in preference to the other forms of tocopherol in the liver. In the present study, developmental changes in expression of α‐TTP after birth were investigated using rats with respect to plasma changes of tocopherols. The expression of α‐TTP in the neonatal rat liver, which was very low immediately after birth, increased steadily during the two weeks of life before weanling and reached the adult level at four weeks. During the suckling period, the plasma ratio of α‐toc to γtoc linearly increased, because plasma α‐toc which was low immediately after birth, increased rapidly during the period, while γtoc remained unchanged. The increase in the ratio seemed to correlate with the developmental expression of α‐TTP in the liver during this period.
A personal overview of vitamin E research
Authors: Mino Makoto
Published: December 2008

This article covers the research topics that I consider to be most impressive and revolutionary, particularly those of clinical relevance.
Plasma membrane receptor for beta‐lactoglobulin and retinol‐binding protein in murine hybridomas
Authors: Mansouri Abdelali , Guéant Jean‐Louis , Capiaumont Josette , Pelosi Paolo , Nabet Pierre , Haertlé Thomas
Published: December 2008

The aim of the present work was to study the binding of [125I]‐BLGA (β‐lactoglobulin variant A) to the plasma membrane fraction of hybrid cells. This binding increased as a function of time with on‐rate and off‐rate constant at 4.47 ± 0.18× 106 M−1 min−1 and 0.17 ± 0.07 min−1, respectively (n = 3). The saturation study showed a single binding site type corresponding to a Kd at 8.26 ± 2.98 nM and 14.02 ± 2.61× 1012 sites per mg of the plasma membrane protein (n = 3). Competitive of binding BLGA was observed with BLGA, complexed with retinol and also with RBP (retinol‐binding protein). Gel filtration of [125I]‐BLGA incubated with Triton X‐100 solubilized membrane showed the formation of a ligand‐receptor complex. Cross‐linking of the tracer to plasma membrane showed a complex with a Mr at 69 kDa, suggesting a receptor M_r of 51 kDa, as seen by autoradiography of SDS‐PAGE.
Search for novel redox groups in mitochondrial NADH:ubiquinone oxidoreductase (complex I) by diode array UV/VIS spectroscopy
Authors: Schulte Ulrich , Abelmann Anke , Amling Natascha , Brors Benedikt , Friedrich Thorsten , Kintscher Lars , Rasmussen Tim , Weiss Hanns
Published: December 2008

The proton‐translocating NADH:ubiquinone oxidoreductase of mitochondria (complex I) is a large L‐shaped multi‐subunit complex. The peripheral matrix arm contains one FMN and a number of iron‐sulfur (FeS) clusters and is involved in NADH oxidation and electron transfer to the membrane intrinsic arm. There, following a yet unknown mechanism, the redox‐driven proton translocation and the ubiquinone reduction take place. Redox groups that would be able to link electron transfer with proton translocation have not been found so far in the membrane arm. We searched for such groups in complex I isolated from Neurospora crassa. Under anaerobic conditions, the preparation was analyzed in different redox states by means of UV/VIS and EPR spectroscopy. Absorption bands in the UV/VIS redox difference spectra were found which cannot be attributed to the FMN or the EPR detectable FeS clusters. The existence of two novel groups is postulated and their possible locations in the electron pathway and their roles in proton translocation are discussed.
The molecular structure of mitochondrial contact sites. Their role in regulation of energy metabolism and permeability transition
Authors: Brdiczka Dieter , Beutner Gisela , Rück Alexander , Dolder Max , Wallimann Theo
Published: December 2008

Contact sites between the outer and peripheral inner membrane of mitochondria are involved in protein precursor uptake and energy transfer. Hexokinase and mitochondrial creatine kinase could be attributed by different techniques to the energy transfer contacts. Kinetic analyses suggested a functional interaction between the kinases, outer membrane pore protein, and inner membrane adenylate translocator (ANT). This suggestion was strongly supported by isolation of hexokinase and creatine kinase complexes that were constituted of kinase oligomers, porin and ANT. Phospholipid vesicles carrying reconstituted kinase—porin—ANT complexes enclosed internal ATP in contrast to vesicles containing free porin only. This indicated that unspecific transport through porin was regulated by its interaction with a specific antiporter, ANT. A direct interaction between porin and ANT in the hexokinase complex conferred the reconstituted system with permeability properties reminiscent of the mitochondrial permeability transition (PT) pore. In the creatine kinase complex this interaction between porin and ANT was replaced by contact of both with the kinase octamer. Thus PT‐pore‐like functions were not observed unless the creatine kinase octamer was dissociated, suggesting that the ANT was locked in the antiporter state by interaction with the octamer. Indeed, reconstituted pure ANT showed PT‐pore‐like properties concerning Ca2+ sensitivity. However, as cyclophilin was missing, sensitivity against cyclosporin was not observed.
New light on mitochondrial calcium
Authors: Pinton Paolo , Brini Marisa , Bastianutto Carlo , Tuft Richard A. , Pozzan Tullio , Rizzuto Rosario
Published: December 2008

The possibility of specifically addressing recombinant probes to mitochondria is a novel, powerful way to study these organelles within living cells. We first showed that the Ca2+‐sensitive photoprotein aequorin, modified by the addition of a mitochondrial targeting sequence, allows to monitor specifically the Ca2+concentration in the mitochondrial matrix ([Ca2+]m) of living cells. With this tool, we could show that, upon physiological stimulation, mitochondria undergo a major rise in [Ca2+]m, well in the range of the Ca2+sensitivity of the matrix dehydrogenases, in a wide variety of cell types, ranging from non excitable, e.g., HeLa and CHO, and excitable, e.g., cell lines to primary cultures of various embryological origin, such as myocytes and neurons. This phenomenon, while providing an obvious mechanism for tuning mitochondrial activity to cell needs, appeared at first in striking contrast with the low affinity of mitochondrial Ca2+uptake mechanisms. Based on indirect evidence, we proposed that the mitochondria might be close to the source of the Ca2+signal and thus exposed to microdomains of high [Ca2+], hence allowing the rapid accumulation of Ca2+into the organelle. In order to verify this intriguing possibility, we followed two approaches. In the first, we constructed a novel aequorin chimera, targeted to the mitochondrial intermembrane space (MIMS), i.e., the region sensed by the low‐affinity Ca2+uptake systems of the inner mitochondrial membrane. With this probe, we observed that, upon agonist stimulation, a portion of the MIMS is exposed to saturating Ca2+concentrations, thus confirming the occurrence of microdomains of high [Ca2+] next to mitochondria. In the second approach, we directly investigated the spatial relationship of the mitochondria and the ER, the source of agonist‐releasable Ca2+in non‐excitable cells. For this purpose, we constructed GFP‐based probes of organelle structure; namely, by targeting to these organelles GFP mutants with different spectral properties, we could label them simultaneously in living cells. By using an imaging system endowed with high speed and sensitivity, which allows to obtain high‐resolution 3D images, we could demonstrate that close contacts (<80 nm) occur in vivo between mitochondria and the ER.
Acquisition of selenium tolerance by a selenium non‐accumulating Astragalus species via selection
Authors: Wang Y. , Böck A. , Neuhierl B.
Published: December 2008

Selection of cultured cells of the selenium sensitive and non‐accumulating Astragalus cicer for tolerance to stepwise increasing concentrations of selenite in the medium lead to a variant able to grow at 75 μM selenite. The Se‐tolerant culture synthesized a selenocysteine methyltransferase immunologically related but not identical to that of the accumulating A. bisulcatus species and produced Se‐methyl‐selenocysteine in vivo. Re‐cultivation in selenium‐free medium lead to breakdown of tolerance and the disappearance of the methyltransferase from cellular proteins. The results prove that the non‐accumulating species A. cicer has the cryptic capacity for synthesis of a selenocysteine methyltransferase and also demonstrate that synthesis of the organoselenium compounds in Se‐accumulating plants are contributing to selenium tolerance.
Characteristics of the production of active oxygen species from adherent and non‐adherent neutrophils
Authors: Yoshida N. , Yoshikawa T. , Nakagawa S. , Miyajima T. , Nakamura Y. , Naito Y. , Tanigawa T. , Kondo M.
Published: December 2008

Our objective was to evaluate the characteristics of the production of AOS from the neutrophils that had adhered to the endothelial cells, fibronectin or polystyrene, using the method of electron paramagnetic resonance (EPR) spin trapping. Neutrophils and endothelial cells were isolated from human venous blood and umbilical veins, respectively. AOS production from neutrophils was not elicited only by adhesion. The stimulation of adherent neutrophils with phorbol myristate acetate (PMA) induced the production of AOS. The production of AOS from adherent neutrophils to endothelial cells, but not to fibronectin or polystyrene, decreased with the interval time between the adhesion and the stimulation by PMA. The amount of AOS produced by the neutrophils adherent to fibronectin or polystyrene was maintained for one hour after stimulation with PMA, whereas that by suspended neutrophils gradually decreased with the time after stimulation.

Results indicate that adherent and non‐adherent neutrophils exhibit differing time course of AOS production.
Kinetic analysis of antioxidant capacity of wine
Authors: Tubaro Franco , Rapuzzi Pierpaolo , Ursini Fulvio
Published: December 2008

A competition kinetics procedure for measuring total antioxidant capacity in wine is described. This procedure is based on the “crocin bleaching test” (Bors et al. Biochim. Biophys. Acta 1984, 796:, 312–319) as modified for analyzing the antioxidant capacity of complex mixtures (Tubaro et al. J. Am. Oil Chem. Soc. 1996,73, 173–179). The antioxidant capacity of white wines ranged from 0.08 to 1.2 mM equivalents of the reference antioxidant (Trolox C), while for red wines values ranging from 6.4 to 41.9 mM have been obtained. Although a correlation exists between antioxidant capacity and total phenol content of wines, due to the variable reactivity of different phenol groups, the analysis of the phenol content provides only a crude indication of the actual antioxidant capacity. The analysis of antioxidant capacity on different polyphenol classes, separated by solid phase extraction, indicated that anthocyanins are the major antioxidants of young red wines, and tannins of old red wines and white wines. Several vintages of the same grape have been analyzed and the expected decrease of antioxidant capacity upon ageing was not observed, although spectrophotometric analysis clearly demonstrated the shift from anthocyanin monomers to polymers. Artificial ageing by stirring under air produced a rapid decrease (30 min) of antioxidant capacity, followed by an increase (up to two weeks), but not any significant modification of the spectrophotometric chemical age factor. Since neither natural nor artificial ageing present a clear‐cut relationship with a decrease of antioxidant capacity, we could conclude that the a priori assumption that an old wine contains less antioxidant capacity, although popular, is not fully correct.
13‐HPODE and 13‐HODE modulate cytokine‐induced expression of endothelial cell adhesion molecules differently
Authors: Friedrichs Bärbel , Toborek Michal , Hennig Bernhard , Heinevetter Lutz , Müller Cordula , Brigelius‐Flohé Regina
Published: December 2008

Expression of cellular adhesion molecules (CAMs) at endothelial surfaces represents a physiological response to vascular damage and mediates the initiation of inflammation and possibly of atherogenesis. The cytokines TNFα and IL‐1 are potent inducers of CAMs in endothelial cells. Reactive oxygen species comprising lipid oxidation products have been implicated in the signaling pathways of both TNFα and IL‐1 and accordingly could modulate atherogenic events. We, therefore, investigated the potential role of the lipoxygenase product, 13‐hydroperoxyoctadecadienoic acid (13‐HPODE), which has also been identified in oxidized low density lipoproteins on CAM expression in HUVEC. 13‐HPODE induced the expression of ICAM‐1 in a concentration dependent manner up to 75 μM. Higher concentrations were toxic. Similar effects were observed with H2O2and phosphatidylcholine hydroperoxide. VCAM‐1 and E‐selectin were not induced by 13‐HPODE. 13‐HPODE administered simultaneously with IL‐1 or TNFα induced ICAM‐1 additively, suggesting that hydroperoxides and cytokines act on the same signaling pathways. In contrast, pretreatment of cells with 50 μM 13‐HPODE for 1 hour rather inhibited subsequent cytokine‐induced ICAM‐1 and E‐selectin expression. Surprisingly, the reduction product of 13‐HPODE, 13‐hydroxyoctadecadienoic acid (13‐HODE) proved to be an even better inducer of ICAM‐1 than 13‐HPODE. Pretreatment with 13‐HODE did not show any inhibitory effect on ICAM‐1 expression.

Our data show that lipoxygenase products differentially affect CAM expression. 13‐HPODE is stimulatory by itself and can positively or negatively affect cytokine signaling depending on time of exposure. 13‐HODE induces CAM expression by itself but does not inhibit cytokine signaling. Thus, the interplay of lipoxygenase products with proinflammatory cytokines can not simply be explained by an oxidant‐mediated facilitation of cytokine signaling.
A multifunctional hydroquinone oxidase of the external cell surface and sera
Authors: Morré D. James , Pogue Rhea , Morré Dorothy M.
Published: December 2008

A multifunctional cell surface protein with NADH oxidase (NOX) activity and capable of oxidizing hydroquinones is located at the exterior of the cell and is shed in soluble form into sera. The oxidase appears to function as a terminal oxidase of a trans plasma membrane electron transport chain consisting of a NAD(P)H‐ubiquinone reductase at the cytosolic membrane surface, possibly a b‐type cytochrome, ubiquinone and the oxidase. Hyperactivity or conditions that interrupt ordered 2H+ + 2e− transport from NAD(P)H or hydroquinone to molecular oxygen and other acceptors at the external cell surface may result in the generation of superoxide. The latter may serve to propagate aging‐related redox changes both to adjacent cells and circulating blood components. A circulating NOX activity form associated with aging and the reduction of cytochrome c by sera of aged patients that is partially inhibited by ubiquinone are described.
Cytosolic NADPH‐UQ reductase, the enzyme responsible for cellular ubiquinone redox cycle as an endogenous antioxidant in the rat liver
Authors: Kishi Takeo , Takahashi Takayuki , Usui Akinori , Hashizume Naoko , Okamoto Tadashi
Published: December 2008

Cellular ubiquinone (UQ) is expected to act as an endogenous antioxidant against oxidative stress. To confirm this, UQ‐reductases which are necessary to regenerate ubiquinol (UQH2) were investigated in rat tissue, and a novel NADPH‐dependent UQ (NADPH‐UQ) reductase was found in cytosol. The cytosolic NADPH‐UQ reductase activity accounted for more than 80% of UQ‐10 reduction by the rat liver homogenate in the presence of NADPH. Furthermore, the NADPH‐UQ reductase activities in various tissues were correlated to the redox states of UQ in the corresponding tissues. Rat liver cytosol with NADPH protected lecithin liposomes containing UQ‐10, as well as UQH2‐10 from AMVN (2,2′‐azobis(2,4‐dimethyl‐valeronitrile))‐induced lipid peroxidation. The enzyme purified from rat liver cytosol, reduced UQ‐10 in lecithin liposomes at approximately the same rate as did cytosol. These results supported that cytosolic NADPH‐UQ reductase is the enzyme responsible for nonmitochondrial UQ reduction acting as an endogenous antioxidant against oxidative stress. The antioxidant role of the UQ redox cycle and NADPH‐UQ reductase was discussed in relation to other cellular NADPH‐dependent antioxidant enzymes.
Mitochondrial coenzyme Q content and aging
Authors: Lass Achim , Kwong Linda , Sohal Rajindar S.
Published: December 2008

The main objective of this study was to determine the nature of the relationship between aging and mitochondrial coenzyme Q (CoQ) content. Mitochondria in the heart, skeletal muscle, kidney and brain of the mouse varied in both the amount of total CoQ (CoQ9+CoQ10) content as well as in the ratio of the CoQ9 to CoQ10. CoQ content declined with age only in the skeletal muscle. Caloric restriction (CR) resulted in an increase in the amount of CoQ9 in skeletal muscle mitochondria. This effect was partially reversible upon termination of the caloric restriction regimen. Results suggest that a decrease in mitochondrial CoQ content is an integral aspect of aging in skeletal muscle.
A role for reduced coenzyme Q in atherosclerosis?
Authors: Thomas Shane R. , Witting Paul K. , Stocker Roland
Published: December 2008

Substantial evidence implicates oxidative modification of low density lipoprotein (LDL) as an important event contributing to atherogenesis. As a result, the elucidation of the molecular mechanisms by which LDL is oxidized and how such oxidation is prevented by antioxidants has been a significant research focus. Studies on the antioxidation of LDL lipids have focused primarily onα‐tocopherol (α‐TOH), biologically and chemically the most active form of vitamin E and quantitatively the major lipid‐soluble antioxidant in extracts prepared from human LDL. In addition toα‐TOH, plasma LDL also contains low levels of ubiquinol‐10 (CoQ10H2; the reduced form of coenzyme Q10). Recent studies have shown that in oxidizing plasma lipoproteinsα‐TOH can exhibit anti‐ or pro‐oxidant activities for the lipoprotein's lipids exposed to a vast array of oxidants. This article reviews the molecular action ofα‐TOH in LDL undergoing “mild” radical‐initiated lipid peroxidation, and discusses how small levels of CoQ10H2 can represent an efficient antioxidant defence for lipoprotein lipids. We also comment on the levelsα‐TOH, CoQ10H2 and lipid oxidation products in the intima of patients with coronary artery disease and report on preliminary studies examining the effect of coenzyme Q10 supplementation on atherogenesis in apolipoprotein E knockout mice.
Distribution of antioxidants among blood components and lipoproteins: Significance of lipids/CoQ10 ratio as a possible marker of increased risk for atherosclerosis
Authors: Tomasetti Marco , Alleva Renata , Solenghi Maria Diana , Littarru Gian Paolo
Published: December 2008

Total CoQ10 levels were evaluated in whole blood and in plasma obtained from a group of 83 healthy donors. Extraction with light petroleum ether/methanol was more efficient, for whole blood, than the extraction which is often used for plasma and serum, i.e., ethanol hexane. An excellent correlation was present between plasma CoQ10 and whole blood CoQ10. CoQ10 is mainly associated with plasma rather than with cellular components. Positive, significant correlations were found between the LDL‐chol/CoQ10 ratio and the total‐chol/HDL‐chol ratio, which is usually considered a risk factor for atherosclerosis. The proportion of CoQ10 carried by LDL was 58 ± 10%, while the amount carried by HDL was 26 ± 8%. In VLDL + IDL CoQ10 was 16 ± 8%. The content of CoQ10 in single classes of lipoproteins is strictly correlated with CoQ10 plasma concentration. In a parallel study conducted on a population of diabetic patients (one IDDM group and one NIDDM) CoQ10 plasma levels were generally higher compared to the control group, also when normalised to total cholesterol. In particular the LDL fraction showed a CoQ10/chol ratio higher in NIDDM but not in IDDM patients, compared to controls. The CoQ10/triglycerides ratio was lower in NIDDM respect to controls and even lower in IDDM patients.
Plasma ubiquinone to ubiquinol ratio in patients with hepatitis, cirrhosis, and hepatoma, and in patients treated with percutaneous transluminal coronary reperfusion
Authors: Yamamoto Yorihiro , Yamashita Satoshi
Published: December 2008

To assess the degree of oxidative stress, we measured plasma ubiquinone‐10 percentage (%CoQ‐10) in total amounts of ubiquinone‐10 in patients with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma, and in age‐matched control subjects. %CoQ‐10 values were 12.9 ± 10.3 (n=28), 10.6 ± 6.8 (n=28), 18.9 ± 11.1 (n=20), and 6.4 ± 3.3 (n=16), respectively, showing a significant increase in oxidative stress in patient groups as compared to control subjects. There were no differences in total amounts of ubiquinone‐10 and ubiquinol‐10 among the four groups. We next measured %CoQ‐10 in plasmas obtained from nine patients treated with percutaneous transluminal coronary angioplasty (PTCA). Plasmas were collected when hospitalized, and at the time (0, 4, 8, 12, 16, and 20 hr, and 1, 2, 3, 4, and 7 days) after the PTCA. %CoQ‐10 values before and right after PTCA were 9.9 ± 2.8 and 11.4 ± 2.0, respectively, reached a maximum (20#150;45) at 1 or 2 days later, and decreased to 7.9 ± 2.7 at 7 days after PTCA, indicating an increase in oxidative stress in patients during coronary reperfusion.
Coenzyme Q10administration and its potential for treatment of neurodegenerative diseases
Authors: Beal M. Flint
Published: December 2008

Coenzyme Q10(CoQ10) is an essential cofactor of the electron transport chain as well as an important antioxidant. Previous studies have suggested that it may exert therapeutic effects in patients with known mitochondrial disorders. We investigated whether it can exert neuroprotective effects in a variety of animal models. We have demonstrated that CoQ10can protect against striatal lesions produced by both malonate and 3‐nitropropionic acid. It also protects against MPTP toxicity in mice. It extended survival in a transgenic mouse model of amyotrophic lateral sclerosis. We demonstrated that oral administration can increase plasma levels in patients with Parkinson's disease. Oral administration of CoQ10significantly decreased elevated lactate levels in patients with Huntington's disease. These studies therefore raise the prospect that administration of CoQ10may be useful for the treatment of neurodegenerative diseases.
Coenzyme Q10 depletion and mitochondrial energy disturbances in rejection development in patients after heart transplantation
Authors: Gvozdjáková Anna , Kucharská Jarmila , Mizera Stanislav , Braunová Zuzana , Schreinerová Zlatica , Schrameková Eva , Pecháň Ivan , Fabián Juraj
Published: December 2008

Sixty endomyocardial biopsies (EMB) and whole blood or plasma samples from 34 patients after heart transplantation (HTx‐pts) were studied. Acute rejection of the transplanted heart was histologically graded as: 0 (without), 0‐1 (incipient), 1 (mild), 2 (moderate). The level of coenzyme Q10 (CoQ10) in 28 EMB was estimated by HPLC. Mitochondrial respiratory chain function and energy production were measured in 60 EMB. This study is the first report showing a correlation between: (a) histological signs of rejection in the human transplanted heart and (b) CoQ10 level of EMB, CoQ10 blood level, and mitochondrial bioenergetic processes: inhibition in FAD‐part, but not in NAD‐part of respiratory chain. In all patients after heart transplantation (HTx‐pts) the dynamic balance between total antioxidant status and degree of oxidative stress was disturbed.

Conclusions: CoQ10 level and mitochondrial bioenergetic functions of EMB contribute to the explanation of pathobiochemical mechanisms of origin and development rejection of human transplanted heart. We suppose that estimation of EMB CoQ10 level could be used as a bioenergetic marker of rejection development in human transplanted heart. CoQ10 therapy could contribute to the prevention of rejection of the transplanted heart.
The effect of coenzyme Q10 administration on metabolic control in patients with type 2 diabetes mellitus
Authors: Eriksson J. G. , Forsén T. J. , Mortensen S. A. , Rohde M.
Published: December 2008

A possible relationship between the pathogenesis of type 2 diabetes and coenzyme Q10 (CoQ10) deficiency has been proposed. The aim of this study was to assess the effect of CoQ10 on metabolic control in 23 type 2 diabetic patients in a randomized, placebo‐controlled trial. Treatment with CoQ10 100 mg bid caused a more than 3‐fold rise in serum CoQ10 concentration (p<0.001). No correlation was observed between serum CoQ10 concentration and metabolic control. No significant changes in metabolic parameters were observed during CoQ10 supplementation. The treatment was well tolerated and did not interfere with glycemic control, therefore CoQ10 may be used as adjunctive therapy in patients with associated cardiovascular diseases.