bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Vitamin D Status in a Representative Sample of Youth From Québec, Canada
Authors: Mark Sean , Gray-Donald Katherine , Delvin Edgard E , O'Loughlin Jennifer , Paradis Gilles , Levy Emile , Lambert Marie 
Published: June 2008

AbstractBackground: Adequate vitamin D status is important for bone growth and mineralization and has been implicated in the regulation of autoimmunity, metabolic function, and cancer prevention. There are no reports of population-based studies on the vitamin D status of Canadian youth, a population with mandatory fortification of foods.Methods: We measured plasma 25-hydroxyvitamin D [25(OH)D], the best indicator of vitamin D status, in a school-based cross-sectional sample of representative French Canadian youth (n = 1753) ages 9, 13, and 16 years living in Québec (latitude: 45°–48°N). Blood samples were collected from January to May 1999. We defined 25(OH)D deficiency as ≤27.5 nmol/L, hypovitaminosis as ≤37.5 nmol/L, and optimal as &gt;75.0 nmol/L.Results: More than 93% of youth in each age and sex group had suboptimal 25(OH)D concentrations. The prevalence of 25(OH)D deficiency increased with age in both sexes (P &lt; 0.0001). It was 2%, 3%, and 13% in 9-, 13-, and 16-year-old boys and 2%, 8%, and 10% in 9-, 13-, and 16-year-old girls. Girls with higher body mass index and girls from households with lower income had lower 25(OH)D concentrations. These effects were not observed in boys.Conclusions: Inadequate vitamin D status is a potentially serious public health problem among children and adolescents in Québec. Youth living at high latitudes in countries with and without mandatory fortification of vitamin D are likely at heightened risk of 25(OH)D deficiency. These results call for renewed efforts to ensure adequate vitamin D intake among growing children and adolescents.
The Myelopoietic Supportive Capacity of Mesenchymal Stromal Cells Is Uncoupled from Multipotency and Is Influenced by Lineage Determination and Interference with Glycosylation
Authors: Morad Vered , Pevsner-Fischer Meirav , Barnees Sivan , Samokovlisky Albena , Rousso-Noori Liat , Rosenfeld Rakefet , Zipori Dov 
Published: June 2008

Abstract
Cultured bone marrow stromal cells create an in vitro milieu supportive of long-term hemopoiesis and serve as a source for multipotent mesenchymal progenitor cells defined by their ability to differentiate into a variety of mesodermal derivatives. This study aims to examine whether the capacity to support myelopoiesis is coupled with the multipotency. Our results show that the myelopoietic supportive ability of stromal cells, whether from the bone marrow or from embryo origin, is not linked with multipotency; cell populations that possess multipotent capacity may or may not support myelopoiesis, whereas others, lacking multipotency, may possess full myelopoietic supportive ability. However, upon differentiation, the ability of multipotent mesenchymal progenitors to support myelopoiesis is varied. Osteogenic differentiation did not affect myelopoietic supportive capacity, whereas adipogenesis resulted in reduced ability to support the maintenance of myeloid progenitor cells. These differences were accompanied by a divergence in glycosylation patterns, as measured by binding to lectin microarrays; osteogenic differentiation was associated with an increased level of antennarity of N-linked glycans, whereas adipogenic differentiation caused a decrease in antennarity. Inhibition of glycosylation prior to seeding the stroma with bone marrow cells resulted in reduced capacity of the stromal cells to support the formation of cobblestone areas. Our data show that myelopoietic support is unrelated to the multipotent phenotype of cultured mesenchymal progenitors but is dependent on the choice of differentiation pathway and upon correct glycosylation of the stromal cells.
Disclosure of potential conflicts of interest is found at the end of this article.
Direct-Current Electrical Field Guides Neuronal Stem/Progenitor Cell Migration
Authors: Li Lei , El-Hayek Youssef H. , Liu Baosong , Chen Yonghong , Gomez Everlyne , Wu Xiaohua , Ning Ke , Li Lijun , Chang Ning , Zhang Liang , Wang Zhengguo , Hu Xiang , Wan Qi 
Published: June 2008

AbstractDirect-current electrical fields (EFs) promote nerve growth and axon regeneration. We report here that at physiological strengths, EFs guide the migration of neuronal stem/progenitor cells (NSPCs) toward the cathode. EF-directed NSPC migration requires activation of N-methyl-d-aspartate receptors (NMDARs), which leads to an increased physical association of Rho GTPase Rac1-associated signals to the membrane NMDARs and the intracellular actin cytoskeleton. Thus, this study identifies the EF as a directional guidance cue in controlling NSPC migration and reveals a role of the NMDAR/Rac1/actin signal transduction pathway in mediating EF-induced NSPC migration. These results suggest that as a safe physical approach in clinical application, EFs may be developed as a practical therapeutic strategy for brain repair by directing NSPC migration to the injured brain regions to replace cell loss.Disclosure of potential conflicts of interest is found at the end of this article.
EWS-FLI1 Causes Neuroepithelial Defects and Abrogates Emigration of Neural Crest Stem Cells
Authors: Coles Edward G. , Lawlor Elizabeth R. , Bronner-Fraser Marianne 
Published: June 2008

AbstractThe most frequently occurring chromosomal translocation that gives rise to the Ewing's sarcoma family of tumors (ESFT) is the chimeric fusion gene EWS-FLI1 that encodes an oncogenic protein composed of the N terminus of EWS and the C terminus of FLI1. Although the genetic basis of ESFT is fairly well understood, its putative cellular origin remains to be determined. Previous work has proposed that neural crest progenitor cells may be the causative cell type responsible for ESFT. However, surprisingly little is known about the expression pattern or role of either wild-type EWS or wild-type FLI1 in this cell population during early embryonic development. Using the developing chick embryo as a model system, we identified EWS expression in emigrating and migratory neural crest stem cells, whereas FLI1 transcripts were found to be absent in these populations and were restricted to developing endothelial cells. By ectopically expressing EWS-FLI1 or wild-type FLI1 in the developing embryo, we have been able to study the cellular transformations that ensue in the context of an in vivo model system. Our results reveal that misexpression of the chimeric EWS-FLI1 fusion gene, or wild-type FLI1, in the developing neural crest stem cell population leads to significant aberrations in neural crest development. An intriguing possibility is that misexpression of the EWS-FLI1 oncogene in neural crest-derived stem cells may be an initiating event in ESFT genesis.Disclosure of potential conflicts of interest is found at the end of this article.
Scalable Selection of Hepatocyte- and Hepatocyte Precursor-Like Cells from Culture of Differentiating Transgenically Modified Murine Embryonic Stem Cells
Authors: Drobinskaya Irina , Linn Thomas , Šarić Tomo , Bretzel Reinhard G. , Bohlen Heribert , Hescheler Jürgen , Kolossov Eugen 
Published: June 2008

Abstract
Potential therapeutic applications of embryonic stem cell (ESC)-derived hepatocytes are limited by their relatively low output in differentiating ESC cultures, as well as by the danger of contamination with tumorigenic undifferentiated ESCs. To address these problems, we developed transgenic murine ESC clones possessing bicistronic expression vector that contains the α-fetoprotein gene promoter driving a cassette for the enhanced green “live” fluorescent reporter protein (eGFP) and a puromycin resistance gene. Under established culture conditions these clones allowed for both monitoring of differentiation and for puromycin selection of hepatocyte-committed cells in a suspension mass culture of transgenic ESC aggregates (“embryoid bodies” [EBs]). When plated on fibronectin, the selected eGFP-positive cells formed colonies, in which intensely proliferating hepatocyte precursor-like cells gave rise to morphologically differentiated cells expressing α-1-antitrypsin, α-fetoprotein, and albumin. A number of cells synthesized glycogen and in some of the cells cytokeratin 18 microfilaments were detected. Major hepatocyte marker genes were expressed in the culture, along with the gene and protein expression of stem/progenitor markers, suggesting the features of both hepatocyte precursors and more advanced differentiated cells. When cultured in suspension, the EB-derived puromycin-selected cells formed spheroids capable of outgrowing on an adhesive substrate, resembling the behavior of fetal mouse hepatic progenitor cells. The established system based on the highly efficient selection/purification procedure could be suitable for scalable generation of ESC-derived hepatocyte- and hepatocyte precursor-like cells and offers a potential in vitro source of cells for transplantation therapy of liver diseases, tissue engineering, and drug and toxicology screening.
Disclosure of potential conflicts of interest is found at the end of this article.
Contributions of a Local Health Examination Survey to the Surveillance of Chronic and Infectious Diseases in New York City
Authors: Gwynn R. Charon , Garg Renu K. , Kerker Bonnie D. , Frieden Thomas R. , Thorpe Lorna E. 
Published: June 2008

Objectives. We sought to evaluate the contribution of the New York City Health and Nutrition Examination Survey (NYC-HANES) to local public health surveillance. Methods. Examination-diagnosed estimates of key health conditions from the 2004 NYC-HANES were compared with the National Health and Nutrition Examination Survey (NHANES) 2003–2004 national estimates. Findings were also compared with self-reported estimates from the Community Health Survey (CHS), an annually conducted local telephone survey. Results. NYC-HANES estimated that among NYC adults, 25.6% had hypertension, 25.4% had hypercholesterolemia, 12.5% had diabetes, and 25.6% were obese. Compared with US adults, NYC residents had less hypertension and obesity but more herpes simplex 2 and environmental exposures (P < .05). Obesity was higher and hypertension was lower than CHS self-report estimates (P < .05). NYC-HANES and CHS self-reported diabetes estimates were similar (9.7% vs 8.7%). Conclusions. NYC-HANES and national estimates differed for key chronic, infectious, and environmental indicators, suggesting the need for local data. Examination surveys may provide more accurate information for underreported conditions than local telephone surveys. Community-level health and nutrition examination surveys complement existing data, providing critical information for targeting local interventions.
Identifying Heterogeneity Among Injection Drug Users: A Cluster Analysis Approach
Authors: Shaw Souradet Y. , Shah Lena , Jolly Ann M. , Wylie John L. 
Published: June 2008

Objectives. We used cluster analysis to subdivide a population of injection drug users and identify previously unknown behavioral heterogeneity within that population. Methods. We applied cluster analysis techniques to data collected in a cross-sectional survey of injection drug users in Winnipeg, Manitoba. The clustering variables we used were based on receptive syringe sharing, ethnicity, and types of drugs injected. Results. Seven clusters were identified for both male and female injection drug users. Some relationships previously revealed in our study setting, such as the known relationship between Talwin (pentazocine) and Ritalin (methylphenidate) use, injection in hotels, and hepatitis C virus prevalence, were confirmed through our cluster analysis approach. Also, relationships between drug use and infection risk not previously observed in our study setting were identified, an example being a cluster of female crystal methamphetamine users who exhibited high-risk behaviors but an absence or low prevalence of blood-borne pathogens. Conclusions. Cluster analysis was useful in both confirming relationships previously identified and identifying new ones relevant to public health research and interventions.
Childhood Socioeconomic Position, Gender, Adult Body Mass Index, and Incidence of Type 2 Diabetes Mellitus Over 34 Years in the Alameda County Study
Authors: Maty Siobhan C. , Lynch John W. , Raghunathan Trivellore E. , Kaplan George A. 
Published: June 2008

Objectives. We examined the association between childhood socioeconomic position and incidence of type 2 diabetes and the effects of gender and adult body mass index (BMI). Methods. We studied 5913 participants in the Alameda County Study from 1965 to 1999 who were diabetes free at baseline (1965). Cox proportional hazards models estimated diabetes risk associated with childhood socioeconomic position and combined childhood socioeconomic position–adult BMI categories in pooled and gender-stratified samples. Demographic confounders and potential pathway components (physical inactivity, smoking, alcohol consumption, hypertension, depression, health care access) were included as covariates. Results. Low childhood socioeconomic position was associated with excess diabetes risk, especially among women. Race and body composition accounted for some of this excess risk. The association between childhood socioeconomic position and diabetes incidence differed by adult BMI category in the pooled and women-only groups. Adjustment for race and behaviors attenuated the risk attributable to low childhood socioeconomic position among the obese group only. Conclusions. Childhood socioeconomic position was a robust predictor of incident diabetes, especially among women. A cumulative risk effect was observed for both childhood socioeconomic position and adult BMI, especially among women.
Maternal Nonstandard Work Schedules and Adolescent Overweight
Authors: Miller Daniel P. , Han Wen-Jui 
Published: June 2008

Objectives. We investigated whether nonstandard work schedules by mothers were associated with adolescent overweight. Methods. We conducted multiple regression analyses using a sample of mother–child pairs (n=2353) from the National Longitudinal Survey of Youth to examine the association between the number of years mothers worked at nonstandard schedules and adolescent overweight at age 13 or 14 years. Separate analyses were also conducted by family income and family type. Results. Child’s body mass index increased significantly if mothers worked either a few years or many years at nonstandard schedules. Risk of overweight was also significantly associated with 1 to 4 and 10 or more years of maternal nonstandard work schedules. In both cases, results were driven by those families with predicted incomes in the 2nd quartile (“near-poor”), with a few or many years of nonstandard work schedules also associated with increased risk of adolescent overweight in 2-parent families. Conclusions. Results indicate the importance of the overlooked association between maternal nonstandard work schedules and adolescent overweight at age 13 or 14 years. Nonstandard work schedules among near-poor families and in 2-parent families may disrupt the work–family balance, affecting adolescent overweight.
Alternatives to the Randomized Controlled Trial
Authors: West Stephen G. , Duan Naihua , Pequegnat Willo , Gaist Paul , Des Jarlais Don C. , Holtgrave David , Szapocznik José , Fishbein Martin , Rapkin Bruce , Clatts Michael , Mullen Patricia Dolan 
Published: June 2008

Public health researchers are addressing new research questions (e.g., effects of environmental tobacco smoke, Hurricane Katrina) for which the randomized controlled trial (RCT) may not be a feasible option. Drawing on the potential outcomes framework (Rubin Causal Model) and Campbellian perspectives, we consider alternative research designs that permit relatively strong causal inferences. In randomized encouragement designs, participants are randomly invited to participate in one of the treatment conditions, but are allowed to decide whether to receive treatment. In quantitative assignment designs, treatment is assigned on the basis of a quantitative measure (e.g., need, merit, risk). In observational studies, treatment assignment is unknown and presumed to be nonrandom. Major threats to the validity of each design and statistical strategies for mitigating those threats are presented.
A 6-Month Exercise Intervention Among Inactive and Overweight Favela-Residing Women in Brazil : The Caranguejo Exercise Trial
Authors: Alves João G. , Gale Catharine R. , Mutrie Nanette , Correia Jailson B. , Batty G. David 
Published: June 2008

Objectives. We examined the viability and efficacy of a known quantity of exercise in facilitating weight loss among previously sedentary or irregularly active overweight and obese adult women residing in a slum (favela) in Brazil. Methods. In this randomized controlled trial, 156 women were randomized to a control or intervention group (78 in each group). Exercise was supervised, consisting of three 50-minute aerobic sessions each week for 6 months. Results. Ninety-one percent (71) of the participants in the intervention group completed 6 months of the exercise program. At 6 months, women in the treatment group showed significant reduction in weight (mean = −1.69 kg; 95% confidence interval [CI] = −2.36,−1.03) and body mass index (mean = −0.63 kg/m2; 95% CI = −0.97, −0.30) compared with controls (P for both < .001). Conclusions. A moderately intense, structured exercise program resulted in modest weight loss in women when sustained for 6 months.
Effect of Hand Hygiene on Infectious Disease Risk in the Community Setting: A Meta-Analysis
Authors: Aiello Allison E. , Coulborn Rebecca M. , Perez Vanessa , Larson Elaine L. 
Published: June 2008

To quantify the effect of hand-hygiene interventions on rates of gastrointestinal and respiratory illnesses and to identify interventions that provide the greatest efficacy, we searched 4 electronic databases for hand-hygiene trials published from January 1960 through May 2007 and conducted meta-analyses to generate pooled rate ratios across interventions (N=30 studies). Improvements in hand hygiene resulted in reductions in gastrointestinal illness of 31% (95% confidence intervals [CI]=19%, 42%) and reductions in respiratory illness of 21% (95% CI=5%, 34%). The most beneficial intervention was hand-hygiene education with use of nonantibacterial soap. Use of antibacterial soap showed little added benefit compared with use of nonantibacterial soap. Hand hygiene is clearly effective against gastrointestinal and, to a lesser extent, respiratory infections. Studies examining hygiene practices during respiratory illness and interventions targeting aerosol transmission are needed.
Association of Park Size, Distance, and Features With Physical Activity in Neighborhood Parks
Authors: Kaczynski Andrew T. , Potwarka Luke R. , Saelens Brian E. 
Published: June 2008

Objectives. We studied whether park size, number of features in the park, and distance to a park from participants’ homes were related to a park being used for physical activity. Methods. We collected observational data on 28 specific features from 33 parks. Adult residents in surrounding areas (n=380) completed 7-day physical activity logs that included the location of their activities. We used logistic regression to examine the relative importance of park size, features, and distance to participants’ homes in predicting whether a park was used for physical activity, with control for perceived neighborhood safety and aesthetics. Results. Parks with more features were more likely to be used for physical activity; size and distance were not significant predictors. Park facilities were more important than were park amenities. Of the park facilities, trails had the strongest relationship with park use for physical activity. Conclusions. Specific park features may have significant implications for park-based physical activity. Future research should explore these factors in diverse neighborhoods and diverse parks among both younger and older populations.
Effects on the Dental Arch Form Using a Preadjusted Appliance with Premolar Extraction in Class I Crowding
Authors: Miyake Hironao , Ryu Tatsuo , Himuro Toshihiko 
Published: June 2008

Abstract
Objective: To determine the dental arch form effects of treatment with a preadjusted appliance (0.022″ slot) performed concomitantly with extraction of premolars in Class I crowding.
Materials and Methods: Twenty-six patients (20.17 ± 12.15 years) with Class I crowding who attained a favorable occlusion after treatment were divided into nonextraction and extraction groups. The three-dimensional coordinates of the FA point of each tooth were determined. The dental arch form was expressed as a quartic polynomial expression with log F value used to represent the dental arch form and calculated using the quadratic and quartic coefficients. Changes in the dental arch form before and after treatment were compared between the groups.
Results: In the extraction group, log F value was significantly higher after treatment, and the upper dental arch became more tapered. The U1-APo was significantly lower after treatment. No change was observed in U1-FH. The anterior teeth demonstrated posterior movement due to sliding mechanics, and torque was controlled. The anterior length of the dental arch became significantly longer after treatment for the maxilla and mandible in both groups. Results demonstrated that the upper dental arch might become tapered after treatment used concomitantly with premolar extraction, as a result of the increase in anterior length while maintaining intercanine width for dealing with crowding of the anterior teeth.
Conclusion: It is necessary to anticipate that the upper dental arch form will become tapered during extraction treatment for Class I crowding and to select an appropriate arch form.
Cephalometric Superimpositions
Authors: Gu Yan , McNamara James A. 
Published: June 2008

Abstract
Objective: To test the hypothesis that there is no difference between the information produced by superimposition of serial lateral headfilms on anatomical structures and that produced by superimposition on metallic implants according to the protocols of Björk.
Materials and Methods: Serial cephalograms of 10 untreated subjects who had tantalum implants placed in the maxilla and mandible during childhood were analyzed. Headfilms taken at six consecutive stages of cervical vertebral maturation (CS1-CS6) for six female and four male subjects were used. Tracings were superimposed according to the methods of superimpositions advocated by the American Board of Orthodontics (ABO). In addition, superimpositions along the inferior border of the mandible were performed. Finally, superimpositions of serial tracings on stable intraosseous implants were made to determine the actual growth and remodeling patterns of the maxilla and mandible.
Results: The ABO maxillary superimposition method underestimates the vertical displacement and overestimates the forward movement of maxillary landmarks. Superimposing on the internal cortical outline of the symphysis and the inferior alveolar nerve canals generally approximates the mandibular superimposition on implants, although the lower anterior border of the symphysis may be a preferable area of superimposition. Superimposition on the lower border of the mandible does not reflect accurately the actual pattern of growth and remodeling of the mandible.
Conclusions: When analyzing serial headfilms, erroneous information concerning patterns of bone growth and remodeling can be obtained if convenient, but biologically incorrect superimposition protocols are used. In addition, tooth movements measured can be distorted significantly depending on the method of superimposition.