bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterogeneous Effect of Peroxisome Proliferator‐activated Receptor γ2 Ala12 Variant on Type 2 Diabetes Risk
Authors: Ludovico Ornella , Pellegrini Fabio , Di Paola Rosa , Minenna Antonio , Mastroianno Sandra , Cardellini Marina , Marini Maria Adelaide , Andreozzi Francesco , Vaccaro Olga , Sesti Giorgio , Trischitta Vincenzo
Published: July 2008

Conflicting results have been reported regarding whether the PPARγ2 Pro12Ala polymorphism plays a role in the risk of type 2 diabetes (T2D), suggesting genetic heterogeneity. To investigate this issue, a meta‐analysis of 41 published and 2 unpublished studies (a total of 42,910 subjects) was conducted. Ala12 carriers had a 19% T2D risk reduction, but this association was highly heterogeneous (p = 0.005). A great proportion (48%) of heterogeneity was explained by the controls’ BMI, with risk reduction being greater when BMI was lower. Risk reduction of Ala12 carriers in Asia (35%) was higher than in Europe (15%, p = 0.02) and tended to be higher than in North America (18%, p = 0.10). Difference between Asians and Europeans was no longer significant (p = 0.15) after adjusting for the controls’ BMI. Studies from Europe were still heterogeneous (p = 0.02) with risk reduction in Ala12 carriers being progressively smaller (test for trend in the odds ratios, p = 0.02) from Northern (26% reduction, p < 0.0001) to Central (10%, p = 0.04) and Southern (0%, p = 0.94) Europe. In conclusion, in our meta‐analysis, the reduced risk of T2D in Ala12 carriers is not homogeneous. It is greater in Asia than in Europe and, among Europeans, it is higher in Northern Europe, barely significant in Central Europe, and nonexistent in Southern Europe.
Omental 11β‐hydroxysteroid Dehydrogenase 1 Correlates with Fat Cell Size Independently of Obesity
Authors: Michailidou Zoi , Jensen Michael D. , Dumesic Daniel A. , Chapman Karen E. , Seckl Jonathan R. , Walker Brian R. , Morton Nicholas M.
Published: July 2008

Objectives: In ideopathic obesity, there is evidence that enhanced cortisol regeneration within abdominal subcutaneous adipose tissue may contribute to adiposity and metabolic disease. Whether the cortisol regenerating enzyme, 11β‐hydroxysteroid dehydrogenase type 1 (11βHSD1), or glucocorticoid receptor (GRα) levels are altered in other adipose depots remains uncertain. Our objective was to determine the association between 11βHSD1 and GRα mRNA levels in four distinct adipose depots and measures of obesity and the metabolic syndrome.

Research Methods and Procedures: Adipose tissue biopsies were collected from subcutaneous (abdominal, thigh, gluteal) and intra‐abdominal (omental) adipose depots from 21 women. 11βHSD1 and GRα mRNA levels were measured by real‐time polymerase chain reaction. Body composition, fat distribution, fat cell size, and blood lipid, glucose, and insulin levels were measured.

Results: 11βHSD1 mRNA was highest in abdominal subcutaneous (p < 0.001) and omental (p < 0.001) depots and was positively correlated with BMI and visceral adiposity in all depots. Omental 11βHSD1 correlated with percent body fat (R = 0.462, p < 0.05), fat cell size (R = 0.72, p < 0.001), and plasma triglycerides (R = 0.46, p < 0.05). Conversely, GRα mRNA was highest in omental fat (p < 0.001). GRα mRNA was negatively correlated with BMI in the abdominal subcutaneous (R = −0.589, p < 0.05) and omental depots (R = −0.627, p < 0.05). Omental GRα mRNA was inversely associated with visceral adiposity (R = −0.507, p < 0.05), fat cell size (R = −0.52, p < 0.01), and triglycerides (R = −0.50, p < 0.05).

Discussion: Obesity was associated with elevated 11βHSD1 mRNA in all adipose compartments. GRα mRNA is reduced in the omental depot with obesity. The novel correlation of 11βHSD1 with omental fat cell size, independent of obesity, suggests that intracellular cortisol regeneration is a strong predictor of hypertrophy in the omentum.
Transcriptomic Characterization of the Long‐term Dihydrotestosterone Effects in Adipose Tissue
Authors: Bolduc Carl , Yoshioka Mayumi , St Amand Jonny
Published: July 2008

Objective: To study the long‐term transcriptomic effects of dihydrotestosterone (DHT) in adipose tissue. Fat distribution is regulated by sexual hormones. It is still unclear if androgens are promoting or reducing intra‐abdominal fat accumulation.

Research Methods and Procedures: Retroperitoneal adipose tissue were isolated from each group of gonadectomized (GDX) C57BL6 male mice treated with vehicle or DHT for 21 days. Serial analysis of gene expression (SAGE) was performed to generate ∼150,000 SAGE tags from each sample.

Results: Among the numerous genes regulated by DHT, transcripts involved in glycolysis, such as aldolase 1 A isoform and pyruvate kinase muscle as well as lipogenic transcripts, such as malic enzyme supernatant and ELOVL family member 6 elongation of long chain fatty acids were down‐regulated by androgen supplementation. In contrast, transcripts involved in lipolysis and fatty acid oxidation, such as carboxylesterase 3, acetyl‐coenzyme A acyltransferase 1, 3‐ketoacyl‐CoA thiolase B and enoyl‐coenzyme A hydratase/3‐hydroxyacyl coenzyme A dehydrogenase were up‐regulated by DHT. Pro‐apoptotic transcripts such as cell death‐inducing DFFA‐like effector c, BCL2/adenovirus E1B 19 kDa‐interacting protein 1 NIP3 and ‐interacting protein 3‐like were up‐regulated by DHT, whereas transcripts involved in promotion of cell cycle such as cyclin D2 were down‐regulated by DHT.

Discussion: These results suggest that chronic androgen treatment may help to improve metabolic profile by regulating various critical pathways involved in adipose tissue physiology. In addition, several genes associated with a healthier metabolic profile, such as adiponectin and CD36 antigen, were up‐regulated by 21 days of DHT treatment.
Dehydroepiandrosterone Sulfate and High‐density Lipoprotein‐cholesterol Levels in Overweight Children
Authors: Garcés Carmen , Cano Beatriz , Lasunción Miguel A. , Mangas Alipio , Benavente Mercedes , De Oya Iría , Studer Alexis , De Oya Manuel
Published: July 2008

Objective: The association of childhood overweight with cardiovascular risk factors seems to change by sex and age, which may indicate that hormonal status could be the cause of this different association. In this study, we analyzed the relationship of dehydroepiandrosterone sulfate (DHEA‐S) with the alterations associated with overweight by analyzing the influence of this hormone in the differences found in biochemical variables between normal‐weight and overweight prepubertal children.

Research Methods and Design: The study included 684 6‐ to 8‐year‐old children (350 boys and 334 girls) categorized by the presence or absence of overweight, according to the age‐ and sex‐specific cut‐off points proposed for children. Lipid levels were determined by standard methods. DHEA‐S and insulin levels were measured by radioimmunoassay. Biochemical variables were compared between normal‐weight and overweight children by tertiles of DHEA‐S.

Results: We observed that plasma high‐density lipoprotein‐cholesterol (HDL‐C) and apolipoprotein (apo)‐AI levels were significantly lower in overweight than in normal‐weight boys only in the highest tertile of DHEA‐S. No significant differences in plasma glucose levels, total cholesterol, low‐density lipoprotein‐cholesterol, or apo B were found between overweight and normal‐weight children in any DHEA‐S tertile. In a Spearman correlation analysis, we observed a significant and negative correlation for weight and BMI with HDL‐C and for weight and apo‐AI levels only in the highest tertile of DHEA‐S.

Discussion: Our study showed that, in our prepubertal population, the association of overweight with decreased HDL‐C and apo‐AI levels was present only in boys within the highest levels of DHEA‐S, supporting the importance of hormonal influences on the association of metabolic alterations with overweight.
Effects of Pronounced Weight Loss on Adiponectin Oligomer Composition and Metabolic Parameters
Authors: Engl Julia , Bobbert Thomas , Ciardi Christian , Laimer Markus , Tatarczyk Tobias , Kaser Susanne , Weiss Helmut , Molnar Clemens , Tilg Herbert , Patsch Josef R. , Spranger Joachim , Ebenbichler Christoph F.
Published: July 2008

Objective: Adiponectin is an adipocytokine secreted into circulation in three isoforms. The aim of the study was to investigate changes of adiponectin isoforms during profound weight loss and its relation to anthropomorphometric and metabolic parameters.

Research Methods and Procedures: Thirteen severely obese female subjects were examined before and 1 year after surgical treatment. Total adiponectin was determined by radioimmunosorbent assay, and oligomer composition was detected by nondenaturing Western blot.

Results: BMI decreased substantially (p < 0.001), which was associated with an increase of total adiponectin from 12.9 ± 5.9 to 14.3 ± 6.1 μg/mL (p = 0.055). Medium molecular weight (MMW) adiponectin increased from 7.5 ± 3.6 to 9.1 ± 4.1 μg/mL (p = 0.009), whereas high (HMW) and low molecular weight adiponectin remained unchanged. Δ values of total adiponectin correlated significantly with Δ values of anthropometric parameters. Similar correlations were found for Δ values of MMW (Δ weight: r2 = 0.4132, p = 0.0178; Δ BMI: r2 = 0.3319, p = 0.0393; Δ fat mass: r2 = 0.5202, p = 0.0054).

Discussion: Thus, profound weight loss was associated with an increase in total adiponectin, which was mainly and consistently caused by increases in MMW adiponectin (p = 0.009). These changes result in a shift from low molecular weight to MMW and HMW adiponectin isoforms, which may be related to improvements in both anthropometric and metabolic parameters.
Probable Blind Spot in the International Diabetes Federation Definition of Metabolic Syndrome
Authors: Chen Hsin‐Jen , Pan Wen‐Harn
Published: July 2008

Objectives: The International Diabetes Federation (IDF) proposed a novel definition of the metabolic syndrome (MS) in 2005, which designated central obesity as mandatory. The new National Cholesterol Education Program (NCEP) version, announced by the American Heart Association and National Heart Lung and Blood Institute in October 2005, did not favor any of the five components. We set out to compare the cardiovascular profiles of patients cross‐defined by these two definitions to shed light on the differential meanings of the two.

Research Methods and Procedures: We analyzed data from 2608 non‐institutionalized adults (≥19 years old) in the National Nutrition and Health Survey in Taiwan, who had complete data for the five MS defining components. Both definitions adopted lower cut‐points for fasting glucose and race‐specific cut‐points for waist circumference.

Results: Under the IDF's and new NCEP's definitions, the MS prevalence was 6.2% and 11.6% in men and 12.6% and 16.5% in women, respectively. Although the two definitions had high agreement, IDF failed to pick up ∼4% to 5% of people with more than three MS component disorders but a waist circumference less than the cut‐point. Subjects whose physical conditions only satisfied NCEP's definition had similar or worse metabolic profiles than those whose conditions satisfied both IDF's definition and the new NCEP's definition.

Discussion: The IDF definition would fail to identify a portion of people who have more than three MS component disorders but a small waistline. Further research and discussion are needed on whether and how to implement the IDF's definition.
Changes in Body Composition with Weight Loss: Obese Subjects Randomized to Surgical and Medical Programs
Authors: Dixon John B. , Strauss Boyd J. G. , Laurie Cheryl , O'Brien Paul E.
Published: July 2008

Objective: To assess changes in body composition with weight loss in obese subjects randomized to a laparoscopic adjustable gastric band surgical program or a medical program using a very‐low‐energy diet and orlistat.

Research Methods and Procedures: Using body composition measurements by DXA, neutron activation for total body nitrogen, and whole body γ counting for total body potassium, we studied changes in fat mass, fat distribution, fat‐free mass, total bone mineral content, total body protein, and body cell mass at 6 (n = 61 paired) and 24 months (n = 53 paired) after randomization.

Results: At 24 months, the surgical group had lost significantly more weight (surgical, 20.3 ± 6.5 kg; medical, 5.9 ± 8.0 kg). There was favorable fat‐free mass to fat mass loss ratios for both groups (surgical, 1:5.5; medical, 1:5.9). Changes in total body nitrogen or potassium were favorable in each group. A small reduction in mean bone mineral content occurred throughout the study but was not associated with extent of weight loss or treatment group. At 6 months, weight loss for both groups was similar (surgical, 14.1 ± 4.5 kg; medical, 13.3 ± 7.3 kg). The medical program subjects lost less fat‐free mass and skeletal muscle and had increased total body protein. The proportion of body fat to limb fat remained remarkably constant throughout the study.

Discussion: Weight loss programs used in this study induced fat loss without significant deleterious effects on the components of fat‐free mass.
Body Mass, DRD4, Physical Activity, Sedentary Behavior, and Family Socioeconomic Status: The Add Health Study
Authors: Guo Guang , North Kari E. , Gorden‐Larsen Penny , Bulik Cynthia M. , Choi Seulki
Published: July 2008

Objective: To investigate the joint role of the 48‐base pair repeat polymorphism of the dopamine receptor 4 gene (DRD4) and environmental factors in body mass variation among an ethnically diverse sample of U.S. adolescents and young adults.

Research Methods and Procedures: Approximately 2600 adolescent and young adults in the National Longitudinal Study of Adolescent Health (Add Health) who provided DNA measures and measures of height and weight were included in the analysis. Mixed regression modeling was used to investigate the effects of the 7R/7R and any5R variants in the DRD4 gene simultaneously with the effects of physical activity (PA), sedentary behavior (SB), and family socioeconomic status (SES) on body mass variation. European Americans, African Americans, and Hispanic Americans were modeled separately.

Results and Discussion: Both the 7R/7R and any5R genotypes of the DRD4 gene were associated with age‐ and sex‐specific BMI percentile score (BMI‐P) based on the Centers for Disease Control and Prevention/National Center for Health Statistics 2000 reference curves among African Americans and only among African Americans (N = 413) 20 years old or younger. Neither genetic variants are associated with the BMI measure among white (N = 1386) and Hispanic‐American (N = 331) adolescents. The presence of the 7R/7R genotype was associated with a reduction of 15.1 in BMI percentile (p = 0.005), and the presence of any5R was associated with an increase of 15.5 in BMI percentile (p = 0.003), after adjusting for PA, SB, and family SES. Neither PA nor SB as measured in Add Health is importantly associated with BMI‐P, suggesting a complex relationship between body mass and PA/SB among adolescents and young adults. Family SES is negatively related to BMI‐P in the European‐American sample.
Analysis of mutant origin recognition complex with reduced ATPase activity in vivo and in vitro
Authors: Takehara Masaya , Makise Masaki , Takenaka Hitomi , Asano Teita , Mizushima Tohru
Published: July 2008

In eukaryotes, ORC (origin recognition complex), a six-protein complex, is the most likely initiator of chromosomal DNA replication. ORC belongs to the AAA+ (ATPases associated with a variety of cellular activities) family of proteins and has intrinsic ATPase activity derived from Orc1p, one of its subunits. To reveal the role of this ATPase activity in Saccharomyces cerevisiae (baker's yeast) ORC, we mutated the Orc1p sensor 1 and sensor 2 regions, which are important for ATPase activity in AAA+ proteins. Plasmid-shuffling analysis revealed that Asn600, Arg694 and Arg704 are essential for the function of Orc1p. In yeast cells, overexpression of Orc1R694Ep inhibited growth, caused inefficient loading of MCM (mini-chromosome maintenance complex of proteins) and slowed the progression of S phase. In vitro, purified ORC-1R [ORC with Orc1R694Ep (Orc1p Arg694→Glu mutant)] has decreased ATPase activity in the presence or absence of origin DNA. However, other activities (ATP binding and origin DNA binding) were indistinguishable from those of wild-type ORC. The present study showed that Arg694 of the Orc1p subunit is important for the ATPase activity of ORC and suggests that this ATPase activity is required for efficient MCM loading on to origin DNA and for progression of S phase.
A possible biochemical link between NADPH oxidase (Nox) 1 redox-signalling and ERp72
Authors: Chen Wei , Shang Wei Hao , Adachi Yoshifumi , Hirose Kunitaka , Ferrari David M. , Kamata Tohru
Published: July 2008

Emerging evidence indicates that Nox (NADPH oxidase) 1-generated ROS (reactive oxygen species) play critical regulatory roles in various cellular processes, yet little is known of direct targets for the oxidase. In the present study we show that one of the proteins selectively oxidized in response to Nox1-generated ROS was ERp72 (endoplasmic reticulum protein 72 kDa) with TRX (thioredoxin) homology domains. Oxidation of ERp72 by Nox1 resulted in an inhibition of its reductase activity. EGF treatment of cells stimulated the Nox1 activity and the activated Nox1 subsequently mediated EGF-induced suppression of the ERp72 reductase activity. Co-immunoprecipitation, GST (glutathione transferase) pulldown assays and mutational analysis, indicated that Nox1 associates with ERp72, which involves its N-terminus encompassing a Ca2+-binding site and the first TRX-like motif. Furthermore, confocal microscopy showed co-localization between Nox1 and ERp72 at the plasma membrane. These results suggest that Nox1 functionally associates with ERp72, regulating redox-sensitive signalling pathways in a cellular context.
Association of human DNA helicase RecQ5β with RNA polymerase II and its possible role in transcription
Authors: Izumikawa Keiichi , Yanagida Mitsuaki , Hayano Toshiya , Tachikawa Hiroyuki , Komatsu Wataru , Shimamoto Akira , Futami Kazunobu , Furuichi Yasuhiro , Shinkawa Takashi , Yamauchi Yoshio , Isobe Toshiaki , Takahashi Nobuhiro
Published: July 2008

Although RecQ5β is a ssDNA (single-stranded DNA)-stimulated ATPase and an ATP-dependent DNA helicase with strand-annealing activities, its cellular function remains to be explored. In the present paper, we used immunopurification and MS-based analyses to show that human DNA helicase RecQ5β is associated with at least four RNAP II (RNA polymerase II) subunits. RecQ5β was also present in complexes immunoprecipitated using three different antibodies against the large subunit of RNAP II, or in complexes immunoprecipitated using an anti-FLAG antibody against either FLAG–RNAP II 33 kDa subunit or FLAG–Pin1. Different regions of the non-helicase domain of the RecQ5β molecule were associated with hypophosphorylated and hyperphosphorylated forms of the RNAP II large subunit independently of DNA and RNA. RecQ5β was also found in nuclear chromatin fractions and associated with the coding regions of the LDL (low-density lipoprotein) receptor and β-actin genes. Knockdown of the RecQ5β transcript increased the transcription of those genes. The results of the present study suggest that RecQ5β has suppressive roles in events associated with RNAP II-dependent transcription.
Reduction of S-nitrosoglutathione by alcohol dehydrogenase 3 is facilitated by substrate alcohols via direct cofactor recycling and leads to GSH-controlled formation of glutathione transferase inhibitors
Authors: Staab Claudia A. , Ålander Johan , Brandt Margareta , Lengqvist Johan , Morgenstern Ralf , Grafström Roland C. , Höög Jan-Olov
Published: July 2008

GSNO (S-nitrosoglutathione) is emerging as a key regulator in NO signalling as it is in equilibrium with S-nitrosated proteins. Accordingly, it is of great interest to investigate GSNO metabolism in terms of competitive pathways and redox state. The present study explored ADH3 (alcohol dehydrogenase 3) in its dual function as GSNOR (GSNO reductase) and glutathione-dependent formaldehyde dehydrogenase. The glutathione adduct of formaldehyde, HMGSH (S-hydroxymethylglutathione), was oxidized with a kcat/Km value approx. 10 times the kcat/Km value of GSNO reduction, as determined by fluorescence spectroscopy. HMGSH oxidation in vitro was greatly accelerated in the presence of GSNO, which was concurrently reduced under cofactor recycling. Hence, considering the high cytosolic NAD+/NADH ratio, formaldehyde probably triggers ADH3-mediated GSNO reduction by enzyme-bound cofactor recycling and might result in a decrease in cellular S-NO (S-nitrosothiol) content in vivo. Formaldehyde exposure affected S-NO content in cultured cells with a trend towards decreased levels at concentrations of 1–5 mM, in agreement with the proposed mechanism. Product formation after GSNO reduction to the intermediate semimercaptal responded to GSH/GSNO ratios; ratios up to 2-fold allowed the spontaneous rearrangement to glutathione sulfinamide, whereas 5-fold excess of GSH favoured the interception of the intermediate to form glutathione disulfide. The sulfinamide and its hydrolysis product, glutathione sulfinic acid, inhibited GST (glutathione transferase) activity. Taken together, the findings of the present study provide indirect evidence for formaldehyde as a physiological trigger of GSNO depletion and show that GSNO reduction can result in the formation of GST inhibitors, which, however, is prevented under normal cellular redox conditions.
Biliverdin reductase is a transporter of haem into the nucleus and is essential for regulation ofHO-1gene expression by haematin
Authors: Tudor Cicerone , Lerner-Marmarosh Nicole , Engelborghs Yves , Gibbs Peter E. M. , Maines Mahin D.
Published: July 2008

hBVR (human biliverdin reductase) is an enzyme that reduces biliverdin (the product of haem oxygenases HO-1 and HO-2 activity) to the antioxidant bilirubin. It also functions as a kinase and as a transcription factor in the MAPK (mitogen-activated protein kinase) signalling cascade. Fluorescence correlation spectroscopy was used to investigate the mobility of hBVR in living cells and its function in the nuclear transport of haematin for induction of HO-1. In transiently transfected HeLa cells only kinase-competent hBVR translocates to the nucleus. A reduced mobility in the nucleus of haematin-treated cells suggests formation of an hBVR–haematin complex and its further association with large nuclear components. The binding of haematin is specific, with the formation of a 1:1 molar complex, and the C-terminal 7-residue fragment KYCCSRK296 of hBVR contributes to the binding. The following data suggest formation of dynamic complexes of hBVR–haematin with chromatin: (i) the reduction of hBVR mobility in the presence of haematin is greater in heterochromatic regions than in euchromatic domains and (ii) hBVR mobility is not retarded by haematin in nuclear lysates that contain only soluble factors. Moreover, hBVR kinase activity is stimulated in the presence of double-stranded DNA fragments corresponding to HO-1 antioxidant and HREs (hypoxia response elements), as well as by haematin. Experiments with nuclear localization, export signal mutants and si-hBVR [siRNA (small interfering RNA) specific to hBVR] indicate that nuclear localization of hBVR is required for induction of HO-1 by haematin. Because gene regulation is energy-dependent and haematin regulates gene expression, our data suggest that hBVR functions as an essential component of the regulatory mechanisms for haem-responsive transcriptional activation.
Functional characterization of ribosomal P1/P2 proteins in human cells
Authors: Martinez-Azorin Francisco , Remacha Miguel , Ballesta Juan P. G.
Published: July 2008

The ‘stalk’ is a large ribosomal subunit domain that regulates translation. In the present study the role of the ribosomal stalk P proteins in modulating ribosomal activity has been investigated in human cells using RNA interference. A strong down-regulation of P2 mRNA and a drastic decrease in P2 protein in a stable human cell line was achieved using a doxycycline-inducible system. Interestingly, the amount of P1 protein was similarly decreased in these cells, in contrast with the expression of P1 mRNA. The loss of P1/P2 proteins produced a decrease in the growth rate of these cells, as well as an altered polysome pattern with reduced translation efficiency, but without affecting the free 40 S/60 S subunit ratio. A decrease in the ribosomal-subunit joining capacity was also observed. These data indicate that P1/P2 proteins modulate cytoplasmic translation by influencing the interaction between subunits, thereby regulating the rate of cell proliferation.
A role for actin in regulating apoptosis/programmed cell death: evidence spanning yeast, plants and animals
Authors: Franklin-Tong Vernonica E. , Gourlay Campbell W.
Published: July 2008

Achieving an understanding of how apoptosis/PCD (programmed cell death) is integrated within cellular responses to environmental and intracellular signals is a daunting task. From the sensation of a stimulus to the point of no return, a programme of cell death must engage specific pro-death components, whose effects can in turn be enhanced or repressed by downstream regulatory factors. In recent years, considerable progress has been made in our understanding of how components involved in these processes function. We now know that some of the factors involved in PCD networks have ancient origins that pre-date multicellularity and, indeed, eukaryotes themselves. A subject attracting much attention is the role that the actin cytoskeleton, itself a cellular component with ancient origins, plays in cell death regulation. Actin, a key cellular component, has an established role as a cellular sensor, with reorganization and alterations in actin dynamics being a well known consequence of signalling. A range of studies have revealed that actin also plays a key role in apoptosis/PCD regulation. Evidence implicating actin as a regulator of eukaryotic cell death has emerged from studies from the Animal, Plant and Fungal Kingdoms. Here we review recent data that provide evidence for an active, functional role for actin in determining whether PCD is triggered and executed, and discuss these findings within the context of regulation of actin dynamics.
Structure, mechanism and regulation of pyruvate carboxylase
Authors: Jitrapakdee Sarawut , St Maurice Martin , Rayment Ivan , Cleland W. Wallace , Wallace John C. , Attwood Paul V.
Published: July 2008

PC (pyruvate carboxylase) is a biotin-containing enzyme that catalyses the HCO3−- and MgATP-dependent carboxylation of pyruvate to form oxaloacetate. This is a very important anaplerotic reaction, replenishing oxaloacetate withdrawn from the tricarboxylic acid cycle for various pivotal biochemical pathways. PC is therefore considered as an enzyme that is crucial for intermediary metabolism, controlling fuel partitioning toward gluconeogenesis or lipogenesis and in insulin secretion. The enzyme was discovered in 1959 and over the last decade there has been much progress in understanding its structure and function. PC from most organisms is a tetrameric protein that is allosterically regulated by acetyl-CoA and aspartate. High-resolution crystal structures of the holoenzyme with various ligands bound have recently been determined, and have revealed details of the binding sites and the relative positions of the biotin carboxylase, carboxyltransferase and biotin carboxyl carrier domains, and also a unique allosteric effector domain. In the presence of the allosteric effector, acetyl-CoA, the biotin moiety transfers the carboxy group between the biotin carboxylase domain active site on one polypeptide chain and the carboxyltransferase active site on the adjacent antiparallel polypeptide chain. In addition, the bona fide role of PC in the non-gluconeogenic tissues has been studied using a combination of classical biochemistry and genetic approaches. The first cloning of the promoter of the PC gene in mammals and subsequent transcriptional studies reveal some key cognate transcription factors regulating tissue-specific expression. The present review summarizes these advances and also offers some prospects in terms of future directions for the study of this important enzyme.
A requirement for thioredoxin in redox-sensitive modulation of T-cadherin expression in endothelial cells
Authors: Joshi Manjunath B. , Ivanov Danila , Philippova Maria , Kyriakakis Emmanouil , Erne Paul , Resink Thérèse J.
Published: July 2008

T-cad (T-cadherin), a glycosylphosphatidylinositol-anchored cadherin superfamily member, is expressed widely in the brain and cardiovascular system, and absent, decreased, or even increased, in cancers. Mechanisms controlling T-cad expression are poorly understood. The present study investigated transcriptional regulation of T-cad in ECs (endothelial cells). Conditions of oxidative stress (serum-deprivation or presence of H2O2) elevate T-cad mRNA and protein levels in ECs. Reporter gene analysis, using serially deleted T-cad promoter stretches ranging from −99 to −2304 bp, located the minimal promoter region of T-cad within −285 bp from the translation start site. Reporter activity in ECs transfected with the −285 bp construct increased under conditions of oxidative stress, and this was normalized by antioxidant N-acetylcysteine. An electrophoretic-mobility-shift assay revealed a specific nucleoprotein complex unique to −156 to −203 bp, which increased when nuclear extracts from oxidatively stressed ECs were used, suggesting the presence of redox-sensitive binding element(s). MS analysis of the nucleoprotein complex unique to −156 to −203 bp after streptavidin–agarose pull-down detected the presence of the redox-active protein thioredoxin. The presence of thioredoxin-1 in a nuclear extract from oxidatively stressed ECs was demonstrated after immunoprecipitation and immunoblotting. Transfection of ECs with thioredoxin-1 small interfering RNA abrogated oxidative-stress-induced up-regulation of T-cad transcripts and protein. We conclude that thioredoxin-1 is an important determinant of redox-sensitive transcriptional up-regulation of T-cad in ECs.
CD95 ligation and intracellular membrane flow
Authors: Reinehr Roland , Häussinger Dieter
Published: July 2008

Whereas ligation of the CD95 death receptor in the plasma membrane of so-called type I cells leads to a direct caspase 8-dependent activation of downstream effector caspases, mitochondrial amplification of caspase 8-derived signals is required in so-called type II cells in order to execute apoptotic cell death. In type I cells CD95L (CD95 ligand) binding to CD95 results in a ceramide-dependent formation of the DISC (death-inducing signalling complex) and caspase 8-dependent CD95 clustering in the plasma membrane, followed by an internalization of these multimeric-receptor–DISC complexes. In contrast, in the hepatocyte, a type II cell, the bulk of CD95 is stored intracellularly under resting conditions and only a few ‘sentinel’ CD95 receptors are present in the plasma membrane. However, their activation by CD95L is sufficient to trigger a caspase 8-dependent endosomal acidification and a ceramide-dependent trafficking of intracellularly stored CD95 to the plasma membrane, thereby amplifying CD95 activation. Thus, in both type I and type II cells, ceramide and CD95 receptor endo- and exo-cytosis are involved in CD95-mediated apoptosis, but apparently in different ways. This, however, is not the only effect of CD95 ligation on intracellular membrane flow in type II cells, and evidence has been presented that soon after CD95 ligation Golgi elements intermix caspase-dependently with mitochondria. In this issue of the Biochemical Journal, Matarrese et al. report another aspect on endocytosis in response to CD95 ligation in type II cells, namely a caspase-independent endocytosis with vesicle translocation to the mitochondrial compartment, suggestive of an interplay between both organelles in the sense of an ‘organelle scrambling’. Thus early effects of CD95 activation on intracellular membrane flow may be much more complex than previously thought, but much has still to be learned about signalling mechanisms and the role they play in apoptosis.
Phosphorylation of Argonaute proteins: regulating gene regulators
Authors: Rüdel Sabine , Meister Gunter
Published: July 2008

Members of the Ago (Argonaute) protein family are the mediators of small RNA-guided gene-silencing pathways including RNAi (RNA interference), translational regulation by miRNAs (microRNAs) and transcriptional silencing. Recent findings by Zeng et al. in this issue of the Biochemical Journal demonstrate that Ago proteins are post-translationally modified by phosphorylation of Ser387. Mutating Ser387 to alanine leads to reduced localization of human Ago2 to cytoplasmic P-bodies (processing bodies), cellular sites where RNA turnover and, at least in part, miRNA-guided gene regulation occurs. Zeng et al. further show that a member of the MAPK (mitogen-activated protein kinase) signalling pathway phosphorylates Ago2 at Ser387, suggesting that Ago2-mediated gene silencing might be linked to distinct signalling pathways.
A New Focus for Parent Education: Bridging the Gap Between Diagnosis and Intensive Early Intervention Services
Authors: Vismara Laurie A. , Rogers Sally J.
Published: July 2008

Research has documented positive effects of parent-implemented interventions for children with autism. This article presents a new approach to family training in children with autism designed to precede intensive early intervention services for children 12-36 months. The Early Start Denver Model consists of 12 one hour per week sessions with families and children focusing on bringing the child into coordinated, interactive social relations, increasing the reward of social engagement, and developing play activities into joint activity routines. Results of a small-scale efficacy study indicate that parents acquired ESDM intervention techniques during the intervention and maintained these skills during follow up assessment. Additionally, children showed improvements for a variety of social and communicative behaviors.
Teaching Self-Initiations within the Natural Environment: A Case Study
Authors: Donaldson Amy L. , Olswang Lesley B.
Published: July 2008

This case study investigates the effects of a multi-element treatment approach to teaching the social-communicative skill of self-initiating to a young child with autism. The participant, James, was a 6-year-old boy diagnosed with autism attending a fully integrated kindergarten classroom. He demonstrated age-appropriate language and non-verbal performance skills; however, teachers reported that he demonstrated difficulty socially interacting with peers. The treatment package targeted use of three types of self-initiations (greeting/attention-getting, commenting, and requesting information). The treatment incorporated individual, dyad, and small-group instruction, and use of untrained peers and highly preferred activities. Following treatment, James demonstrated an increase in all types of self-initiations with peers. Results are discussed with regard to clinical application within the natural environment.
Research Consumerism 101: Evaluating External Evidence of Treatment Effectiveness
Authors: Coyle James L.
Published: July 2008

The modern clinician is a research consumer. Rehabilitation of oropharyngeal impairments, and prevention of the adverse outcomes of dysphagia, requires the clinician to select interventions for which evidence of a reasonable likelihood of a successful, important outcome exists. The purpose of this paper is to provide strategies for evaluation of published research regarding treatment of oropharyngeal dysphagia. This article utilizes tutorial and examples to inform and educate practitioners in methods of appraising published research. It provides and encourages the use of methods of efficiently evaluating the validity and clinical importance of published research. Additionally, it discusses the importance of the ethical obligation we, as practitioners, have to use evidence-based treatment selection methods and measurement of patient performance during therapy. The reader is provided with tactics for evaluating treatment studies to establish a study's validity and, thereby, objectively select interventions. The importance of avoiding subjective or unsubstantiated claims and using objective methods of generating empirical clinical evidence is emphasized. The ability to evaluate the quality of research provides clinicians with objective intervention selection as an important, essential component of evidence-based clinical practice.

ASHA Code of Ethics (2003):

Principle I, Rule F:
“Individuals shall fully inform the persons they serve of the nature and possible effects of services rendered and products dispensed…” (p. 2)

Principle I, Rule G:
“Individuals shall evaluate the effectiveness of services rendered and of products dispensed and shall provide services or dispense products only when benefit can reasonably be expected.” (p. 2)

Principle IV, Rule G:
“Individuals shall not provide professional services without exercising independent professional judgment, regardless of referral source or prescription.” (p. 4)
Theoretical study of the nucleation/growth process of carbon clusters under pressure
Authors: Pineau N. , Soulard L. , Los J. H. , Fasolino A.
Published: July 2008

We used molecular dynamics and the empirical potential for carbon LCBOPII to simulate the nucleation/growth process of carbon clusters both in vacuum and under pressure. In vacuum, our results show that the growth process is homogeneous and yields mainly sp2 structures such as fullerenes. We used an argon gas and Lennard–Jones potentials to mimic the high pressures and temperatures reached during the detonation of carbon-rich explosives. We found that these extreme thermodynamic conditions do not affect substantially the topologies of the clusters formed in the process. However, our estimation of the growth rates under pressure are in much better agreement with the values estimated experimentally than our vacuum simulations. The formation of sp3 carbon was negligible both in vacuum and under pressure which suggests that larger simulation times and cluster sizes are needed to allow the nucleation of nanodiamonds.
Anomalous growth of Ni3Si2 in bulk Ni/Si interdiffusion
Authors: Borivent D. , Billia B. , Paret J.
Published: July 2008

In the case of reactive interdiffusion of a binary system, growth interfaces between phases generally adopt plane front morphology. However, a few cases exist, as in the binary diffusion couples Ni–Si, Mo–Si, and Fe–Al, for which an intermediate phase may grow with an irregular needlelike morphology. We present an analysis of the Ni3Si2 formation by reactive interdiffusion in the Ni–Si system, characterizing the needles and their growth by optical and scanning electron microscopy, x-ray diffraction, and microtomography. The observations are consistent with a diffusion-controlled mechanism with preferred direction of very fast diffusion, from which it follows that the Ni3Si2 needle morphology is due to an anisotropic diffusion mechanism.
An experimental and theoretical investigation of a magnetically confined dc plasma discharge
Authors: Rondanini Maurizio , Cavallotti Carlo , Ricci Daria , Chrastina Daniel , Isella Giovanni , Moiseev Tamara , von Känel Hans
Published: July 2008

A magnetically confined dc plasma discharge sustained by a thermionic source was investigated using a combined experimental and theoretical approach. The discharge originates in an arc plasma source and is expanded in a cylindrical chamber, where it is stabilized by an annular anode. The plasma expansion is contained by an axial magnetic field generated by coils positioned at the top and the bottom of the reactor. The plasma reactor design allows control of the energy of ions impinging on the substrate and thus a high electron density of about 1017 m−3 at 1 Pa can be reached. The plasma is studied using a model composed of the Poisson and of the charged species continuity equations, solved in the flow and temperature fields determined by solving the Navier–Stokes and Fourier equations. The model equations are integrated using the finite element method in a two-dimensional axial symmetric domain. Ionization rates are either assumed constant or determined by solving the Boltzmann transport equation in the local electric field with the Monte Carlo (MC) method. Electron and ion transport parameters are determined by accounting for magnetic confinement through a simplified solution of the ion and electron momentum conservation equations, which yielded parameters in good agreement with those determined with the MC simulations. Calculated electron densities and plasma potentials were satisfactorily compared to those measured using a Langmuir probe. The model demonstrates that the intensity of the magnetic field greatly influences the electron density, so that a decrease by a factor of 2 in its intensity corresponds to a decrease by almost an order of magnitude of the electron and ion concentrations.
Effect of electrode polarity on wire explosion in vacuum
Authors: Rousskikh A. G. , Pil’tikhina D , Baksht R. B. , Beilis I. I. , Chaikovsky S. A.
Published: July 2008

This paper presents experimental results on electrical explosions of thin tungsten wires at wire currents of 0.04–0.4 kA and current rise times of several tens of nanoseconds. The experiment was performed for both negative and positive polarity of the high-voltage electrode. In addition to conventional current and voltage measurements, the current to a grounded cylindrical collector placed between the exploded wire and the return conductor was measured. The collector current was observed only for a 6 μm wire exploded with the high-voltage electrode being at a negative potential. In all other test modes (a 6 μm wire exploded with electrode positive polarity, 6 μm wire exploded with electrodes enclosed in ceramic tubes, 30 μm wires exploded with electrode negative and positive polarities) no collector current was detected. A model of the discharge initiation during a wire explosion (WE) in vacuum has been proposed which is based on the supposition that a surface discharge develops over the electrodes. The presence of plasma-emitted electrons at the cathode surface makes it possible to interpret the experimental results on WEs at different electrode polarities reported both in this paper and in previous publications.
Submicron mapping of silicon-on-insulator strain distributions induced by stressed liner structures
Authors: Murray Conal E. , Saenger K. L. , Kalenci O. , Polvino S. M. , Noyan I. C. , Lai B. , Cai Z.
Published: July 2008

Strain distributions within a silicon-on-insulator (SOI) layer induced by overlying compressively stressed Si3N4 features were measured using x-ray microbeam diffraction. A comparison of analytical and numerical mechanical models of the depth-averaged strain distributions to the measured strain profiles in the SOI layer indicated a blanket film stress of −2.5 GPa in the Si3N4 features. A two-dimensional boundary element model, implemented to analyze thin film/substrate systems, reproduced the observed strain distributions better than an edge-force formulation due to the incorporation of loading along the Si3N4/Si interface.
Ultrahigh current-carrying capability in clean MgB2 films
Authors: Zhuang C. G. , Meng S. , Zhang C. Y. , Feng Q. R. , Gan Z. Z. , Yang H. , Jia Y. , Wen H. H. , Xi X. X.
Published: July 2008

We have studied the current-carrying capability of high quality epitaxial MgB2 films synthesized using the hybrid physical-chemical vapor deposition technique by both transport measurement in nanobridge constrictions and magnetization measurement. An extremely high self-field critical current density Jc(0)>108A∕cm2, approaching the theoretical depairing current of MgB2, was observed on a 150nm bridge, indicating an excellent current-carrying capability in these films. The magnetization measurement also showed very high Jc.
Flexible top gate pentacene thin film transistor with embedded source-drain electrode
Authors: Kim Tae-il , Son Sang Jun , Seo Soon-min
Published: July 2008

Top gate pentacene thin film transistor operating at low voltage was established on flexible poly(ethylene terephthalate) substrate by multilayer transfer fabrication. Source and drain electrodes were embedded in a flexible substrate. Thin polymer film and metal oxide layer prepared from metal electrode by oxygen plasma treatment were used as dielectrics. Top gate organic thin film transistor was achieved by transferring pentacene/poly(vinyl phenol)/Al2O3∕Al layers onto flexible electrodes embedded substrate. Simple approaches for fabricating low voltage operating device were developed and these approaches could pave the simple way to realize flexible devices.
Creation of nanopatterns by local protonation of P4VP via dip pen nanolithography
Authors: Maedler C. , Chada S. , Cui X. , Taylor M. , Yan M. , La Rosa A.
Published: July 2008

The elastic mechanical response of a poly(4-vinylpyridine) film is exploited to create nanostructures under ambient conditions via dip pen nanolithography. Using a pH 4 phosphate buffer solution as the “ink,” a series of experimental results indicates that the nanometer-sized structures are due to local swelling of the film’s pyridyl groups upon their protonation with the hydronium ions delivered by the tip. Control over the structures’ height is gained by properly selecting the writing velocities or the dwell time, respectively.
Legendre polynomial modeling of composite bulk acoustic wave resonators
Authors: Raherison A. , Ratolojanahary F. E. , Lefebvre J. E. , Elmaimouni L.
Published: July 2008

The Legendre polynomial method has been extended to the modeling of bulk acoustic wave (BAW) resonators. Modifications have been made to the formulation in order to account for large differences in the physical properties of adjoining layers and to take into account the electric source. A unique formalism has been obtained which allows for both harmonic and modal analyses. Resonance and antiresonance frequencies, electric input impedance, electromechanical coupling coefficients, and quality factors have been obtained for an aluminum/zinc oxide/aluminum (Al∕ZnO∕Al) BAW resonator. The results are in excellent agreement with analytical results.
Structural and dynamical properties of a core-softened fluid in a supercritical region
Authors: Egorov S. A.
Published: July 2008

We present a theoretical study of the structural, thermodynamic, and transport properties of a supercritical fluid comprising particles interacting via isotropic attractive core-softened potential. The shear viscosity and self-diffusion coefficient are computed on the basis of the mode-coupling theory, with required structural input obtained from the thermodynamically self-consistent integral equation theory. We also consider dilute solutes in a core-softened fluid and use the anisotropic integral equation theory to obtain the solute-solute potential of mean force, which yields the second virial coefficient. We analyze its dependence on the solvent density and solute-solvent interaction strength.
Ordered clusters and free volume in a Zr–Ni metallic glass
Authors: Liu X. J. , Chen G. L. , Hui X. , Liu T. , Lu Z. P.
Published: July 2008

The atomic arrangement of a model metallic glass Zr2Ni was studied by extended x-ray absorption fine structure and x-ray scattering experiments combined with reverse Monte Carlo simulation imposed an additional potential constraint. By an approach to calculating the free volume (FV) on atomic level, we have found a connection between the coordination number and FV, and then revealed that the atomic structure of Zr2Ni metallic glass is essentially an association of the ordered clusters and FV. The ordered clusters about 1.5nm consist of a densely packed core (i.e., icosahedral or fcc-type packing) and the surrounding loosely packed clusters with large FV.