bluuebunny/crossref_metadata_2025 huggingface dataset:
Windage sources in smooth-walled rotating disc systems
Authors: Coren D , Childs P R N , Long C A
Published: January 2009

This article presents experimental data and an associated correlation for the windage resulting from a disc rotating in air, characteristic of gas turbine engines and relevant to some electrical machine applications. A test rig has been developed that uses an electric motor to drive a smooth bladeless rotor inside an enclosed pressurized housing. The rig has the capability of reaching rotational and throughflow Reynolds numbers representative of a modern gas turbine. A moment coefficient has been used to allow a non-dimensional windage torque parameter to be calculated and an agreement with the relevant data in the literature has been found within 10 per cent. Infrared measurements have been performed that allow direct surface temperatures of the rotating disc to be obtained. Laser Doppler anemometry measurements have been made that allow velocities in the flow field of the rotor—stator cavity to be examined and tangential velocities corresponding to rotationally and radially dominated flow conditions are shown. The importance of the flow regime in relation to the resulting windage has been identified and in particular it is noted that windage is a function not only of the ratio of rotational and radial flow dominance as defined by the turbulence parameter, but also for a given value of the turbulence parameter, the magnitude of the rotationally induced and superimposed flows. The experiments extend the range of data available for windage in rotor—stator systems and have been used to produce a correlation suitable for applications operating up to the range of Reψ=107.
Dynamic stability analysis of a flexible cam mechanism using a one-degree-of-freedom model
Authors: Tounsi M , Hbaieb R , Chaari F , Fakhfakh T , Haddar M
Published: January 2009

This article presents an efficient and accurate stability analysis for a flexible cam mechanism based on the multiple scales method. A shaft-cam-follower mechanism is modelled by a one-degree-of freedom model. An equivalent stiffness of a lumped parameter system is developed. Instability regions are determined through a parametric study in order to avoid dangerous working velocities. The equation of motion of the system is resolved using the implicit Newmark algorithm and numerical results are presented in the case of stable and unstable regimes. The results show a concordance between instability regions and dynamic response. The cases of modi-fied trapezoidal and cycloidal cam-profiles are treated and a comparison of the results with an experimental study of the literature is made.
Experimental study on natural ventilation performance of a two-sided wind catcher
Authors: Montazeri H , Azizian R
Published: January 2009

Experimental wind tunnel and smoke visualization testing was conducted to investigate the performance of a two-sided wind catcher. This type of wind catcher is divided internally into two halves for the purposes of air supply and extract. In this study, the two-sided wind catcher model was constructed of two similar one-sided wind catcher models, which were attached back to back. These one-sided models are 1: 40 scale models of Kharmani's School wind catcher in the city of Yazd. Experimental investigations were carried out using an open-circuit wind tunnel, and both the induced volumetric airflow into the building and the pressure coefficients around all surfaces of the wind catcher model were measured at various wind angles. Additional experimental tests and computational fluid dynamics simulation of the wind catcher in the wind tunnel were also conducted in order to assess the accuracy of measurement procedures and the uncertainty of experimental results. To evaluate the stack effects on the natural ventilation performance of a two-sided wind catcher system, the results were compared to the corresponding results of a one-sided one. As a result of placing urban full-scale wind catchers in the boundary layer of atmospheric winds, the effect of this phenomenon was also examined experimentally. The experiments were performed when the wind catcher model with an adjoining house was placed in the wake of upstream objects, resembling neighbouring buildings. It was found that for an isolated two-sided wind catcher model, maximum efficiency is achieved at an air incident angle of 90°, and this can only be explained by the domination of a stack effect rather than dynamic pressure. At this air incident angle the wind catcher efficiency is ≈20 per cent more than the one at zero angle. The results show that the approaching air incident angles, the presence of an object upstream of the structure, and the blowing of atmospheric wind, influence phenomena such as pressure coefficients, induced airflow rate, and the airflow pattern of the two-sided wind catcher. The results show the potential of the two-sided wind catcher as a passive device for providing natural ventilation in buildings.
The linear form of a group II intron catalyzes efficient autocatalytic reverse splicing, establishing a potential for mobility
Authors: Roitzsch Michael , Pyle Anna Marie
Published: January 2009

Self-splicing group II introns catalyze their own excision from pre-RNAs, thereby joining the flanking exons. The introns can be released in a lariat or linear form. Lariat introns have been shown to reverse the splicing reaction; in contrast, linear introns are generally believed to perform no or only poor reverse splicing. Here, we show that a linear group II intron derived from ai5γ can reverse the second step of splicing with unexpectedly high efficiency and precision. Moreover, the linear intron generates dramatically more reverse-splicing product than its lariat equivalent. The finding that linear group II introns can readily undergo the critical first step of mobility by catalyzing efficient reverse splicing into complementary target molecules demonstrates their innate potential for mobility and transposition and raises the possibility that reverse splicing by linear group II introns may have played a significant role in certain forms of intron mobility and lateral gene transfer during evolution.
Evaluating Value-at-Risk Models with Desk-Level Data
Authors: Berkowitz Jeremy , Christoffersen Peter , Pelletier Denis
Published: January 2009

We present new evidence on disaggregated profit and loss (P/L) and value-at-risk (VaR) forecasts obtained from a large international commercial bank. Our data set includes the actual daily P/L generated by four separate business lines within the bank. All four business lines are involved in securities trading and each is observed daily for a period of at least two years. Given this unique data set, we provide an integrated, unifying framework for assessing the accuracy of VaR forecasts. We use a comprehensive Monte Carlo study to assess which of these many tests have the best finite-sample size and power properties. Our desk-level data set provides importance guidance for choosing realistic P/L-generating processes in the Monte Carlo comparison of the various tests. The conditional autoregressive value-at-risk test of Engle and Manganelli (2004) performs best overall, but duration-based tests also perform well in many cases.

This paper was accepted by John Birge, focused issue editor.
Killer facts, politics and other influences: what evidence triggered early childhood intervention policies in Australia?
Authors: Bowen Shelley , Zwi Anthony B. , Sainsbury Peter , Whitehead Margaret
Published: January 2009

Understanding the ‘evidence’ for policy is complicated. This article examines the relationship between evidence and policies on early childhood interventions in two states of Australia, revealing powerful insights into what constitutes the evidence for policy and the importance of ‘killer facts’ to decision makers. The nature of evidence in the policy environment is broad and complex, going well beyond research to incorporate policy context and processes. These findings reinforce an evidence-informed approach to health policy making and the need for researchers to develop a more sophisticated understanding of the policy context.
Increasing capacity for knowledge translation: understanding how some researchers engage policy makers
Authors: Kothari Anita , MacLean Lynne , Edwards Nancy
Published: January 2009

The potential for research to influence policy, and for researchers to influence policy actors, is significant. The purpose of this qualitative study was to explore the experiences of health services researchers engaging in (or not able to engage in) policy-relevant research. Semi-structured telephone interviews were completed with 23 experienced researchers. The results paint a complex and dynamic picture of the policy environment and the relationship between government officials and academic researchers. Elements of this complexity included diverse understandings of the nature of policy and how research relates to policy; dealing with multiple stakeholders in the policy-making process; and identifying strategies to manage the different cultures of government and academia.
Engaging policy makers in action on socially determined health inequities: developing evidence-informed cameos
Authors: Priest Naomi , Waters Elizabeth , Valentine Nicole , Armstrong Rebecca , Friel Sharon , Prasad Amit , Solar Orielle
Published: January 2009

This article describes an innovative knowledge translation project involving researchers and key stakeholders commissioned by the World Health Organization (WHO) for the Commission on Social Determinants of Health (CSDH). The project aimed to develop ‘cameo’ reports of evidence-based policies and interventions addressing social determinants of health, intended for use by leaders and advocates, as well as policy and programme decision makers, to advance global action. The iterative process of developing the framework and content of the cameos, in the context of a limited evidence base, is described, and a number of issues related to the integration of multiple sources of evidence for knowledge translation action are identified.
Knowledge exchange strategies for interventions and policy in public health
Authors: Kouri Denise
Published: January 2009

Promoting the use of research-based knowledge in public health becomes more complex when public health includes interventions on health determinants. This article examines strategies for knowledge synthesis, translation and exchange (KSTE) in the context of public health in Canada, making reference to the work of the recently established National Collaborating Centres for Public Health (NCCs). NCCs simultaneously pursue KSTE and study how KSTE strategies meet different needs. Because NCCs are focused on interventions and policies, they must address the relationship between knowledge and policy, and how amenable it is to change. KSTE can seek to respond to and inform an existing policy agenda, but it can also seek to shape, frame and change that agenda. The two paths might call for different approaches, and for expanding the boundaries of KSTE in health.
Using evidence to inform policy in a non-governmental public body
Authors: Nocon Andrew
Published: January 2009

This article explores the use of evidence to inform policy within a UK public sector body. It examines the way policy makers define the kind of evidence they need, how they go about getting it and what they do with it once they have got it. It also considers the role of specialist research managers within that process, and the differences and relationship between research and other evidence. The article highlights the need for clear planning with regard to the skills needed to ensure the gathering of relevant and high-quality evidence, and for an interactive role in which specialist researchers can make a more substantial contribution to policy development.
Comparison of Immunoassays for the Selective Measurement of Human High–Molecular Weight Adiponectin
Authors: Liu Dan , Schuster Tibor , Baumann Marcus , Roos Marcel , Sollinger Daniel , Lutz Jens , Heemann Uwe , von Eynatten Maximilian
Published: January 2009

Background: Adiponectin is an adipocyte-derived hormone circulating in different multimer complexes. The high–molecular-weight (HMW) complex is likely the active form of this protein and has been recognized as a risk marker for type 2 diabetes and coronary artery disease (CAD). Because quantification of HMW adiponectin by Western blot analysis is time-consuming, novel ELISAs have been developed to simplify measurements in clinical research. However, these enzyme immunoassays have not been cross-validated in larger patient groups. We evaluated 2 individual ELISA systems by comparison to Western blotting for measurement of the distribution of HMW adiponectin in healthy individuals and patients with CAD and type 2 diabetes.

Methods: We measured HMW adiponectin in 204 individuals (83 CAD patients, 81 type 2 diabetes patients, and 40 healthy controls). Correlations, range of agreement, and imprecision of HMW concentrations obtained using 2 commercial ELISAs (#1, ALPCO Diagnostics; #2, Millipore) were evaluated by comparison with quantitative Western blotting.

Result: Adiponectin results of the ELISAs were significantly correlated with those obtained by Western blotting (both r > 0.75, P < 0.001). Deming regression and Bland-Altman analyses indicated high agreement among the 3 immunoassays. The median difference between HMW adiponectin concentrations measured by ELISA and by Western blot was +0.4 mg/L for ELISA #1 and −0.4 mg/L for ELISA #2 with 95% of value differences <3 mg/L.

Conclusions: Selective measurement of HMW adiponectin by ELISA is feasible; however, individual differences among immunoassays must be considered. The evaluated ELISAs exhibit analytical characteristics that allow their use as equivalent for Western blot analysis in larger clinical and epidemiological groups.
High-Sensitivity Chemiluminescence Immunoassays for Detection of Growth Hormone Doping in Sports
Authors: Bidlingmaier Martin , Suhr Jennifer , Ernst Andrea , Wu Zida , Keller Alexandra , Strasburger Christian J , Bergmann Andreas
Published: January 2009

Background: Recombinant human growth hormone (rhGH) is abused in sports, but adequate routine doping tests are lacking. Analysis of serum hGH isoform composition has been shown to be effective in detecting rhGH doping. We developed and validated selective immunoassays for isoform analysis with potential utility for screening and confirmation in doping tests.

Methods: Monoclonal antibodies with preference for pituitary hGH (phGH) or rhGH were used to establish 2 pairs of sandwich-type chemiluminescence assays with differential recognition of rhGH (recA and recB) and phGH (pitA and pitB). We analyzed specimens from volunteers before and after administration of rhGH and calculated ratios between the respective rec- and pit-assay results.

Results: Functional sensitivities were <0.05 μg/L, with intra- and interassay imprecision ≤8.4% and ≤13.7%, respectively. In 2 independent cohorts of healthy subjects, rec/pit ratios (median range) were 0.84 (0.09–1.32)/0.81 (0.27–1.21) (recA/pitA) and 0.68 (0.08–1.20)/0.80 (0.25–1.36) (recB/pitB), with no sex difference. In 20 recreational athletes, ratios (median SD) increased after a single injection of rhGH, reaching 350% (73%) (recA/pitA) and 400% (93%) (recB/pitB) of baseline ratios. At a moderate dose (0.033 mg/kg), mean recA/pitA and recB/pitB ratios remained significantly increased for 18 h (men) and 26 h (women). After high-dose rhGH (0.083 mg/kg), mean rec/pit ratios remained increased for 32 h (recA/pitA) and 34 h (recB/pitB) in men and were still increased after 36 h in women.

Conclusions: Using sensitive chemiluminescence assays with preferential recognition of phGH or rhGH, detection of a single injection of rhGH was possible for up to 36 h.
Reducing Routine Ionized Calcium Measurement
Authors: Baird Geoffrey S , Rainey Petrie M , Wener Mark , Chandler Wayne
Published: January 2009

Background: Ionized calcium (iCa) is measured frequently in hospitalized patients, and hypocalcemia is frequently found, seemingly supporting the practice.

Methods: We retrieved the results of 58 040 iCa tests and records of intravenous (IV) and oral calcium supplementation from laboratory and hospital information systems and evaluated them for frequency of testing, frequency of hypocalcemia, and effects of calcium supplementation.

Results: Serial and daily iCa testing was common and responsible for a substantial fraction of all iCa tests ordered. Half of all patients tested had iCa values below the reference interval. IV, but not oral, calcium therapy increased mean iCa concentrations, but the effect of calcium administration was small compared with the spontaneous increase in iCa that occurred in similar patients who received no calcium treatment. A retrospective analysis suggested that a low total calcium (tCa) concentration (<2.00 mmol/L, <8 mg/dL) could identify most patients with low iCa (<1.0 mmol/L). Introduction of a reflexive strategy reduced iCa testing by 72%–76% and reduced IV calcium gluconate therapy by 45%–81%.

Conclusions: Testing for iCa and IV calcium supplementation were significantly reduced with a reflexive calcium testing strategy that provided iCa testing only to patients with low tCa. Adverse clinical outcomes possibly associated with hypocalcemia did not increase.
Prime Time for Enzymatic Creatinine Methods in Pediatrics
Authors: Cobbaert Christa M , Baadenhuijsen Henk , Weykamp Cas W
Published: January 2009

Background: The literature regarding the nonspecificity of applications of the Jaffe (alkaline picrate) reaction for creatinine is generally outdated. We conducted a specificity study to update the nonspecificity information for current Jaffe and enzymatic creatinine assays.

Methods: Two serum pools with creatinine concentrations within the pediatric reference interval were spiked with albumin, IgG, unconjugated bilirubin, adult hemoglobin (Hb A), and fetal hemoglobin (Hb F) to produce 1 unspiked and 5 spiked samples per pool. The 35 laboratories participating in the survey used a total of 14 method–analyzer combinations. Measurements were performed in triplicate in a single run in accordance with manufacturer instructions. Absolute differences in creatinine concentration between spiked and unspiked samples were calculated per laboratory. Mixed ANOVA was used to quantify the interferent-related CV component for the Jaffe and enzymatic methods.

Results: The interference by bilirubin and Hb A on serum creatinine measurements was <10% for most of the Jaffe and enzymatic methods. Obvious interference was observed among the Jaffe methods in samples spiked with Hb F, albumin, and IgG, but not among the enzymatic methods. The within-laboratory interferent-related CVs for the Jaffe method–analyzer combinations ranged from 8.0%–27% at a creatinine concentration of 40.4 μmol/L (0.46 mg/dL) and from 5.4%–15% at 73.4 μmol/L (0.83 mg/dL). Enzymatic methods had within-laboratory interferent-related CVs of <4% at both concentrations.

Conclusions: Albumin, IgG, and Hb F interfered with Jaffe creatinine assays, leading to inaccuracies in estimated glomerular filtration rates that are clinically important, especially in children and neonates. Because protein error and Hb F interference do not occur with any of the enzymatic methods tested, we conclude that enzymatic creatinine methods are preferred for evaluation of kidney function in pediatric cases.
Automated Determination of Serum α1-Antitrypsin by Antitryptic Activity Measurement
Authors: Roche Denis , Mesner Alexandra , Al Nakib Malik , Leonard Frederic , Beaune Philippe
Published: January 2009

Background: α1-Antitrypsin (A1AT) deficiency is currently detectable by protein immunoassay, phenotyping, and genotyping of the S and Z mutations, but no fully automated method for standard biochemical analyzers is yet available. Here, we present a method that measures the antitryptic activity in serum. This method is rapid, automated, and allows the easy evaluation of a large cohort of patients.

Methods: Our automated assay involves determining serum antitryptic capacity on the Olympus AU 400 autoanalyzer by using trypsin and succinylated gelatin as substrate in the presence of trinitrobenzene sulfonic acid. The results are expressed as a percentage of inhibition of the reaction of trypsin with succinylated gelatin. After we performed analytical validation studies and reference-interval determination based on serum samples from 120 healthy persons, we tested the assay on deidentified samples from 120 patients with various pathologies (primarily pulmonary) of unexplained origin and normal A1AT concentrations and phenotypes.

Results: The analysis rate was up to 120 samples per hour. Intraassay CVs ranged from 3.1%–16.2%, and interassay CV was 7.5%. The reference population showed mean (SD) 58.4 (6.7)% inhibition. The detection limit was 9.5% inhibition. The 120 studied patients displayed significantly lower mean activity than 120 healthy individuals (P < 0.0001).

Conclusion: This assay is stable, reliable, and easily automated by use of open-system analyzers, allowing for the rapid evaluation of patients. After further validation on a larger randomized cohort, this new approach should function as a useful method to explore A1AT deficiency, especially in large-scale studies.
Apolipoprotein B and Cardiovascular Disease Risk: Position Statement from the AACC Lipoproteins and Vascular Diseases Division Working Group on Best Practices
Authors: Contois John H , McConnell Joseph P , Sethi Amar A , Csako Gyorgy , Devaraj Sridevi , Hoefner Daniel M , Warnick G Russell
Published: January 2009

Background: Low-density lipoprotein cholesterol (LDL-C) has been the cornerstone measurement for assessing cardiovascular risk for nearly 20 years.

Content: Recent data demonstrate that apolipoprotein B (apo B) is a better measure of circulating LDL particle number (LDL-P) concentration and is a more reliable indicator of risk than LDL-C, and there is growing support for the idea that addition of apo B measurement to the routine lipid panel for assessing and monitoring patients at risk for cardiovascular disease (CVD) would enhance patient management. In this report, we review the studies of apo B and LDL-P reported to date, discuss potential advantages of their measurement over that of LDL-C, and present information related to standardization.

Conclusions: In line with recently adopted Canadian guidelines, the addition of apo B represents a logical next step to National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII) and other guidelines in the US. Considering that it has taken years to educate physicians and patients regarding the use of LDL-C, changing perceptions and practices will not be easy. Thus, it appears prudent to consider using apo B along with LDL-C to assess LDL-related risk for an interim period until the superiority of apo B is generally recognized.
Evaluation of the VITROS 5,1 FS analyzer in a large clinical laboratory: comparison of methods using different specimens and chemistry systems / Evaluation des Systems VITROS 5,1 FS in einem großen klinischen Laboratorium: Methodenvergleiche mit verschiedenen Probenmaterialien und Systemen
Authors: Aufenanger Johannes , Sonntag Oswald
Published: January 2009

The clinical chemical analysis system Vitros 5,1 FS (Ortho Clinical Diagnostics, Neckargemünd, Germany) combines on one platform multilayer film technology with a newly developed technology based on conventional wet chemistry. We report the first extensive evaluation of this novel analyzer, establishing precision data, accuracy, and linearity of MicroSlide technology analytes and analytes using the newly developed MicroTip technology. For comparison, measurements with the analysis systems Beckman-Coulter DXC800 and Immage or Siemens Healthcare Diagnostics Dimension Xpand, and plasma, serum, urine and cerebrospinal fluid (CSF) samples as well as blood from routine operations were employed, respectively. For within-run imprecision, coefficients of variation between 0.2% and 5.5% were calculated. Coefficients of variation for quality control materials from day-to-day ranged from 0.6% to 7.1%. In all examined analytes, except hemoglobin A1c, calculated inaccuracies were within the acceptable ranges of the national directives for quality assurance (RiliBÄK, directives issued by the German Medical Association). Method comparison demonstrated good agreement between MicroSlide assays and wet chemistry methods with correlation coefficients ranging from 0.872 to 0.998. For the MicroTip assays, the calculated correlation coefficients ranged from 0.968 to 0.994. In conclusion, the Vitros 5,1 FS analyzer is a reliable analysis system which can be easily integrated into clinical chemical routine and which can also be applied for analysis of CSF, urine, and blood samples.
Therapiemonitoring der Multiplen Sklerose / Therapy monitoring of multiple sclerosis
Authors: Deisenhammer Florian
Published: January 2009

Die Therapie der Multiplen Sklerose (MS) hat sich in den letzten Jahren um eine beträchtliche Zahl an verschiedenen Medikamenten erweitert, welche sich durch verschiedene Wirkmechanismen unterscheiden. Der Haupteffekt dieser medikamentösen Therapien liegt in der Reduktion der klinischen Schubrate, welche im Schnitt unter einer Attacke pro Jahr liegt und damit ein relativ seltenes Ereignis darstellt. Somit ist die Bewertung des Therapieerfolges aufgrund der rein klinischen Beobachtung schwierig und ein laborgestütztes Therapiemonitoring wäre hilfreich und ist in manchen Fällen auch möglich. Die Mehrzahl der Medikamente ist auch mit laborchemischen Nebenwirkungen behaftet, weshalb auch diesbezügliche Verlaufskontrollen mitunter notwendig sind.

In diesem Artikel werden die laborgestützten Möglichkeiten der Therapieüberwachung in Hinblick auf Wirksamkeit und Sicherheit der MS-Therapien besprochen.
Inadequacies of glucocorticoid replacement and improvements by physiological circadian therapy
Authors: Debono Miguel , Ross Richard J , Newell-Price John
Published: January 2009

Patients with adrenal insufficiency need lifelong glucocorticoid replacement, but many suffer from poor quality of life, and overall there is increased mortality. Moreover, it appears that use of glucocorticoids at the higher end of the replacement dose range is associated with increased risk for cardiovascular and metabolic bone disease. These data highlight some of the inadequacies of current regimes.

The cortisol production rate is estimated to be equivalent to 5.7–7.4 mg/m2per day, and a major difficulty for replacement regimes is the inability to match the distinct circadian rhythm of circulating cortisol levels, which are low at the time of sleep onset, rise between 0200 and 0400 h, peaking just after waking and then fall during the day. Another issue is that current dose equivalents of glucocorticoids used for replacement are based on anti-inflammatory potency, and few data exist as to doses needed for equivalent cardiovascular and bone effects. Weight-adjusted, thrice-daily dosing using hydrocortisone (HC) reduces glucocorticoid overexposure and represents the most refined regime for current oral therapy, but does not replicate the normal cortisol rhythm. Recently, proof-of-concept studies have shown that more physiological circadian glucocorticoid therapy using HC infusions and newly developed oral formulations of HC have the potential for better biochemical control in patients with adrenal insufficiency. Whether such physiological replacement will have an impact on the complications seen in patients with adrenal insufficiency will need to be analysed in future clinical trials.
Minimal oxidative load: a prerequisite for thyroid cell function
Authors: Poncin Sylvie , Colin Ides M , Gérard Anne-Catherine
Published: January 2009

In addition to reactive oxygen species (ROS) produced by mitochondria during aerobic respiration, thyrocytes are continuously producing H2O2, a key element for hormonogenesis. Because nothing is known about ROS implication in normal non-stimulated cells, we studied their possible involvement in thyrocytes incubated with a potent antioxidant, N-acetylcysteine (NAC). NAC, which blocked the production of intracellular ROS, also decreased dual oxidases, thyroperoxidase, pendrin, and thyroglobulin protein and/or gene expression. By contrast, Na+/I− symporter mRNA expression was unaffected. Among antioxidant systems, peroxiredoxin (PRDX) five expression was reduced by NAC, whereas peroxiredoxin three increased and catalase remained unchanged. In vivo, the expression of both dual oxidases and peroxiredoxin five proteins was also decreased by NAC. In conclusion, when intracellular ROS levels drop below a basal threshold, the expression of proteins involved in thyroid cell function is hampered. This suggests that keeping ROS at a minimal level is required for safeguarding thyrocyte function.
Adult mouse intrahepatic biliary epithelial cells induced in vitro to become insulin-producing cells
Authors: Nagaya Masaki , Katsuta Hitoshi , Kaneto Hideaki , Bonner-Weir Susan , Weir Gordon C
Published: January 2009

Transdifferentiation of cells from a patient's own liver into pancreatic β-cells could be useful for β-cell replacement. We hypothesized that intrahepatic biliary epithelial cells (IHBECs) could become a new source of insulin-producing cells. IHBECs isolated from adult mice were expanded using our novel culture method termed, collagen-embedded floating culture method (CEFCM). With CEFCM, IHBECs formed three-dimensional ductal cysts and rapidly expanded their number by about 15-fold within 2 weeks. Over 90% of cells were positive for cytokeratin 7 and 19. At day 14, IHBECs were transfected with adenoviral (Ad)- pancreas duodenum homeobox 1 (Pdx-1), NeuroD or Pdx-1/VP16. After 7 additional days in serum- and insulin-free differentiation medium (DM), cell phenotypes were determined by RT-PCR, immunostaining and ELISA for insulin. In DM control IHBECs started to express some endocrine progenitor genes (Neurog3, NeuroD, Nkx6.1, and Pdx-1) but lacked insulin gene (Ins) mRNA. Transduced expression of PDX-1, NEUROD or PDX-1/VP16 led to expression of not only INS but also GLUT2 and prohormone convertase 1 and 2. About 3% of 4000 cells counted in PDX-1/VP16 transduced cultures stained strongly for C-peptide suggesting that a subpopulation may have the capacity for differentiation. Transduced cells released insulin (Ad-PDX-1 0.08±0.05, Ad-NEUROD 0.33±0.09, Ad-PDX-1/VP16 0.37±0.14 ng/1×105 cells after 48 h in culture). IHBECs can be markedly expanded, and then with molecular manipulation a subpopulation of these cells can differentiate towards a β-cell phenotype. This approach may lead to a new source of β-cells that can be used for transplantation in diabetes.
Stability of Cytoplasmic Male Sterility in Maize under Different Environmental Conditions
Authors: Weider Christophe , Stamp Peter , Christov Nikolai , Hüsken Alexandra , Foueillassar Xavier , Camp Karl‐Heinz , Munsch Magali
Published: January 2009

Cytoplasmic male sterility (CMS) is a maternally transmitted trait, whereby a plant is unable to produce viable pollen. Studies have revealed that this trait is a tool for enabling efficient and reliable coexistence between genetically modified (GM) and non‐GM cultivation by biocontainment of GM maize (Zea mays L.) pollen. Maize has three types of male‐sterile cytoplasm (T, S, and C), the fertility of which can be restored by nuclear rf genes or by interactions with the environment. Twenty‐two CMS versions of modern European maize hybrids were evaluated in 17 environments in Switzerland, France, and Bulgaria, with two or three sowing dates, in 2005 and 2006. Stable and unstable male sterility occurred in all three CMS types. T‐cytoplasm hybrids were the most stable, while S‐cytoplasm hybrids often showed partial restoration of fertility. C‐cytoplasm was similar to T‐cytoplasm with regard to maintaining male sterility. Climatic factors, especially air temperature, evapotranspiration, and water vapor, during the 10 d before anthesis as well as during anthesis, were correlated positively or negatively with the partial reversion to male fertility of CMS hybrids, indicating an interaction between genetic and climatic factors. This study illustrates that T‐ and C‐cytoplasm in particular open up viable prospects for containing transgenic pollen, especially for Bt‐maize.
FOXO1 Plays an Important Role in Enhanced Microvascular Cell Apoptosis and Microvascular Cell Loss in Type 1 and Type 2 Diabetic Rats
Authors: Behl Yugal , Krothapalli Padmaja , Desta Tesfahun , Roy Sayon , Graves Dana T.
Published: January 2009

OBJECTIVE

To investigate early events leading to microvascular cell loss in diabetic retinopathy.

RESEARCH DESIGN AND METHODS

FOXO1 was tested in vivo by DNA binding activity and by nuclear translocation in microvascular cells in retinal trypsin digests. In vivo studies were undertaken in STZ-induced diabetic rats and Zucker diabetic fatty rats using the tumor necrosis factor (TNF)-specific blocker, pegsunercept, or by inhibiting FOXO1 with RNAi. Microvascular cell apoptosis, formation of pericyte ghosts, and acellular capillaries were measured. Upstream and downstream effects of high-glucose–induced FOXO1 were tested on rat microvascular endothelial cells (RMECs) by small-interfering RNA (siRNA) in vitro.

RESULTS

DNA binding or nuclear translocation of FOXO1, which was reduced by TNF inhibition, was elevated in type 1 and type 2 diabetic retinas. Diabetes stimulated microvascular cell apoptosis; pericyte ghost and acellular capillary development was inhibited by FOXO1 siRNA. High glucose in vitro decreased FOXO1 phosphorylation and DNA binding activity and decreased Akt phosphorylation in RMECs. High-glucose–stimulated FOXO1 DNA binding activity was mediated through TNF-α and formation of reactive oxygen species (ROS), while inhibitors of TNF and ROS and FOXO1 siRNA reduced high-glucose–enhanced RMEC apoptosis. The caspase-3/7 activity and capacity of high glucose to increase mRNA levels of several genes that regulate RMEC activation and apoptosis were knocked down by FOXO1 siRNA.

CONCLUSIONS

FOXO1 plays an important role in rat retinal microvascular cell loss in type 1 and type 2 diabetic rats and can be linked to the effect of high glucose on FOXO1 activation.
BMI Changes During Childhood and Adolescence as Predictors of Amount of Adult Subcutaneous and Visceral Adipose Tissue in Men
Authors: Kindblom Jenny M. , Lorentzon Mattias , Hellqvist Åsa , Lönn Lars , Brandberg John , Nilsson Staffan , Norjavaara Ensio , Ohlsson Claes
Published: January 2009

OBJECTIVE

The amount of visceral adipose tissue is a risk factor for the metabolic syndrome. It is unclear how BMI changes during childhood and adolescence predict adult fat distribution. We hypothesized that there are critical periods during development for the prediction of adult subcutaneous and visceral fat mass by BMI changes during childhood and adolescence.

RESEARCH DESIGN AND METHODS

Detailed growth charts were retrieved for the men participating in the population-based Gothenburg Osteoporosis and Obesity Determinants (GOOD) Study (n = 612). Body composition was analyzed using dual-energy X-ray absorptiometry and adipose tissue areas using abdominal computed tomography at 18 to 20 years of age.

RESULTS

The main finding in the present study was that subjects with increases in BMI Z score of more than 1 SD during adolescence had, independent of prepubertal BMI, both larger subcutaneous (+138%; P < 0.001) and visceral adipose tissue areas (+91%; P < 0.001) than subjects with unchanged BMI Z-score. In contrast, subjects with increases in BMI Z score of more than 1 SD during late childhood had a larger amount of adult subcutaneous adipose tissue (+83%; P < 0.001) than subjects with unchanged BMI Z score but an unaffected amount of visceral adipose tissue. BMI changes during adolescence predict both visceral and subcutaneous adipose tissue of the abdomen, whereas BMI changes during late childhood predict only the subcutaneous adipose tissue.

CONCLUSIONS

The amount of visceral adipose tissue in young adult men was associated with BMI changes specifically during adolescence, whereas the amount of subcutaneous adipose tissue was associated with BMI changes during both late childhood and adolescence.
Common Variants of Hepatocyte Nuclear Factor 1β Are Associated With Type 2 Diabetes in a Chinese Population
Authors: Wang Congrong , Hu Cheng , Zhang Rong , Bao Yuqian , Ma Xiaojing , Lu Jingyi , Qin Wen , Shao Xinyu , Lu Junxi , Xu Jing , Lu Huijuan , Xiang Kunsan , Jia Weiping
Published: January 2009

OBJECTIVE

Hepatocyte nuclear factor 1β (HNF1β) is a transcription factor that is critical for pancreatic cell formation and glucose homeostasis. Previous studies have reported that common variants of HNF1β were associated with type 2 diabetes in Caucasians and West Africans. However, analysis in the subjects from the Botnia study and Malmö Preventive Project produced conflicting results, and the role for HNF1β in type 2 diabetes susceptibility remains unclear. We therefore investigated common variants across the HNF1β gene in a Chinese population.

RESEARCH DESIGN AND METHODS

Fifteen tagging single nucleotide polymorphisms (SNPs) were analyzed for association with type 2 diabetes in subjects with type 2 diabetes (n = 1,859) and normal glucose regulation (n = 1,785).

RESULTS

Consistent with the initial study, we observed evidence that the risk G allele of rs4430796 in intron 2 was significantly associated with type 2 diabetes (odds ratio 1.16 [95% CI 1.05–1.29], P = 0.0035, empirical P = 0.0475). Furthermore, the at-risk G allele was associated with earlier age at diagnosis in the type 2 diabetic subjects (P = 0.0228).

CONCLUSIONS

The result of this study provides evidence that variants in the HNF1β region contribute to susceptibility to type 2 diabetes in the Chinese population.
TCF7L2 Regulates Late Events in Insulin Secretion From Pancreatic Islet β-Cells
Authors: da Silva Xavier Gabriela , Loder Merewyn K. , McDonald Angela , Tarasov Andrei I. , Carzaniga Raffaella , Kronenberger Katrin , Barg Sebastian , Rutter Guy A.
Published: January 2009

OBJECTIVE

Polymorphisms in the human TCF7L2 gene are associated with reduced insulin secretion and an increased risk of type 2 diabetes. However, the mechanisms by which TCF7L2 affect insulin secretion are still unclear. We define the effects of TCF7L2 expression level on mature β-cell function and suggest a potential mechanism for its actions.

RESEARCH DESIGN AND METHODS

TCF7L2 expression in rodent islets and β-cell lines was altered using RNAi or adenoviral transduction. β-Cell gene profiles were measured by quantitative real-time PCR and the effects on intracellular signaling and exocytosis by live cell imaging, electron microscopy, and patch clamp electrophysiology.

RESULTS

Reducing TCF7L2 expression levels by RNAi decreased glucose- but not KCl-induced insulin secretion. The glucose-induced increments in both ATP/ADP ratio and cytosolic free Ca2+ concentration ([Ca2+]i) were increased compared with controls. Overexpression of TCF7L2 exerted minor inhibitory effects on glucose-regulated changes in [Ca2+]i and insulin release. Gene expression profiling in TCF7L2-silenced cells revealed increased levels of mRNA encoding syntaxin 1A but decreased Munc18–1 and ZnT8 mRNA. Whereas the number of morphologically docked vesicles was unchanged by TCF7L2 suppression, secretory granule movement increased and capacitance changes decreased, indicative of defective vesicle fusion.

CONCLUSION—TCF7L2 is involved in maintaining expression of β-cell genes regulating secretory granule fusion. Defective insulin exocytosis may thus underlie increased diabetes incidence in carriers of the at-risk TCF7L2 alleles.
Type 1 Diabetes in the BB Rat: A Polygenic Disease
Authors: Wallis Robert H. , Wang KeSheng , Marandi Leili , Hsieh Eugene , Ning Terri , Chao Gary Y.C. , Sarmiento Janice , Paterson Andrew D. , Poussier Philippe
Published: January 2009

OBJECTIVE

Two type 1 diabetes susceptibility genes have been identified in the spontaneously diabetic biobreeding diabetes-prone (BBDP) rat, the major histocompatibility complex (MHC) (RT1) class II u haplotype (Iddm1) and Gimap5 (Iddm2). The strong effects of these have impeded previous efforts to map additional loci. We tested the hypothesis that type 1 diabetes is a polygenic disease in the BBDP rat.

RESEARCH DESIGN AND METHODS

We performed the most comprehensive genome-wide linkage analysis for type 1 diabetes, age of disease onset (AOO), and insulitis subphenotypes in 574 F2 animals from a cross-intercross between BBDP and type 1 diabetes–resistant, double congenic ACI.BBDP-RT1u,Gimap5 (ACI.BB1u.lyp) rats, where both Iddm1 and Iddm2 were fixed as BBDP.

RESULTS

A total of 19% of these F2 animals developed type 1 diabetes, and eight type 1 diabetes susceptibility loci were mapped, six showing significant linkage (chromosomes 1, 3, 6 [two loci], 12, and 14) and two (chromosomes 2 and 17) suggestive linkage. The chromosomes 6, 12, and 14 intervals were also linked to the severity of islet infiltration by immunocytes, while those on chromosomes 1, 6 (two loci), 14, 17, and a type 1 diabetes–unlinked chromosome 8 interval showed significant linkage to the degree of islet atrophy. Four loci exhibited suggestive linkage to AOO on chromosomes 2 (two loci), 7, and 18 but were unlinked to type 1 diabetes. INS, PTPN22, IL2/IL21, C1QTNF6, and C12orf30, associated with human type 1 diabetes, are contained within the chromosomes 1, 2, 7, and 12 loci.

CONCLUSIONS

This study demonstrates that the BBDP diabetic syndrome is a complex, polygenic disease that may share additional susceptibility genes besides MHC class II with human type 1 diabetes.
Body height differentiation by season of birth: Girls from Cracow, Poland
Authors: Puch Elżbieta Alicja , Krenz-Niedbała Marta , Chrzanowska Maria
Published: January 2009

Published studies world wide demonstrate that measures of human development and health status vary depending on the month of birth but these patterns are not always consistent and sometimes even conflict. Direct factors related to the birth season that may significantly differentiate morphological and functional traits and mechanisms causing these relations have not been found so far. On the basis of cross-sectional material, gathered in the years 1983 and 2000 by the Department of Anthropology of the Academy of Physical Education in Cracow, two main hypotheses have been verified: (1) average body height differences by month of birth are statistically insignificant, (2) the magnitude of these differences does not change with time. Metric data of 4672 girls aged 5-18 years, born in 1965-1978 and 1982-1995, were used. The total sample was also subdivided into prepubertal (5-9 years) and adolescent (10-18 years) groups. The age of the individuals was calculated to the nearest day and the procedure of standardization on the interpolated values of regional norms was applied. A highly significant relationship between the birth month and average values of height was revealed in preadolescent girls. The results obtained for the entire material proved insignificant. The patterns of the month-of-birth effect on body height for girls born in 60./70. and 80./90. show high similarity, though the effect seems weaker in the latter sample. Winter proved to be the most favorable birth season for later body height.
Report on the D32 CCR5 variant in the Sudanese Shagia tribe
Authors: Kempińska-Podhorodecka Agnieszka , Knap Oktawian , Parczewski Miłosz , Bińczak-Kuleta Agnieszka , Parafiniuk Mirosław
Published: January 2009

The focus on small isolated populations provides important insights into the factors affecting the distribution of inheritable traits. Here, we present a report on the distribution of the CCR5 Δ32 mutation in the so far unstudied innate Sudanese population of Shagia people. The genetic material (buccal swabs) was collected from 125 individuals living in three African villages, Abu Haraz, Shibabit and El Higiena. The DNA was extracted, the polymorphic site PCR-amplified with a pair of specific primers flanking the Δ32 CCR5 mutation and reaction products electrophoretically separated in agarose gel. In the Abu Haraz and Shibabit villages, all investigated individuals were found to be homozygous for the wildtype of the receptor, while in El Higiena village one wt/D32 homozygote was identified with the remaining individuals homozygous for non-mutated CCR5. The frequency for the Δ32 CCR5 allele was 0,4%, with Δ32/wt genotype frequency of 0,8%. This is the first report on the presence of the Δ32 CCR5 allele not only in the genetically isolated Shagia tribe but also in the region of the Sudan.
Unemployment in the Polish countryside and its effect on the development and rate of maturation of rural girls
Authors: Olszewska Elżbieta , Łaska-Mierzejewska Teresa
Published: January 2009

The aim of this study is to assess the biological status of girls from landless rural families - daughters of working fathers, and those of unemployed fathers. The measures include age at menarche, body height and weight, and the body mass index (BMI). The study of rural girls was conducted in 2001; a total of 9599 girls aged 9-18 were examined. The material used in the present article only embraces girls from non-farming rural families (N = 4476). It was divided into daughters of working fathers (86.5%) and those of unemployed fathers (13.5%). Daughters of working fathers mature earlier than those of unemployed fathers. The difference in the age at menarche is 0.39 years and is statistically significant. The age at menarche of daughters of unemployed fathers approximates the menarchal age of daughters from farming families with many children (5 or more) in which both parents have elementary education. In groups similar in terms of the father's education and the number of children in the family, daughters of unemployed fathers display a later age at menarche and a lower body height and weight. These results support the statement that a father's lack of employment affects the biological status of his daughters.
A re-examination of a human femur found at the Blind River Site, East London, South Africa: Its age, morphology, and breakage pattern
Authors: Wang Qian , Tobias Phillip V. , Roberts David L. , Jacobs Zenobia
Published: January 2009

Modern human femoral features might have appeared in the early Middle Stone Age (156 ka to 20 ka) in South Africa, as demonstrated by the recent re-examination of a human femur fossil found at the Blind River Site, East London in the 1930s, if new dating results hold. Two optically stimulated luminescence dates from the relocated original Blind River shallow marine/estuarine deposits that contained the femur gave almost identical ages of ~120 ka, corresponding to the early part of the Last Interglacial (Oxygen Isotope Stage 5). Overall, the slender headless femur is of modern human form. The distal epiphysis bears some typical squatting features, including a newly recognized squatting facet on the anterior wall of the intercondylar fossa. With the typical V-shaped and oblique fracture pattern left by the missing head, the Blind River femur was most likely modified through human activity. But this style is not a cultural trait found in recent South African people. Further study is needed to place this specimen in its due context in the course of human evolution.