153 research outputs found
Short-Term Reduction in Energy Availability Does Not Impair Exercise-Induced Gains in Bone Formation Rate
Reduced energy availability (EA, defined as total energy intake minus exercise energy expenditure) can induce significant bone loss in humans and in rodents, but this effect may vary with exercise status. Purpose: This study focused on the effects of graded reductions in EA achieved with and without exercise on mid-shaft tibia cortical bone. We hypothesized that markers of bone formation would be reduced with 4 weeks of decreased EA, but these reductions would be mitigated in exercising animals. Methods: After 8 weeks of acclimation to AIN-93M purified diet, 5 mo-old virgin female Sprague-Dawley rats (n=72) were randomized in to sedentary (SED) and exercise (EX) groups, each of which was divided into 3 energy status groups: -12% EA/g body mass (-12EA) and -25% EA/g body mass (-25EA) vs. ad lib-fed controls. EX rats were restricted on diet intake slightly less than SED to account for the energy cost (+10%/day) of treadmill running (80-90 min/d, 4 d/wk, ~60% VO2max); custom versions of AIN-93M were used to assure restriction of only kcal (other nutrients at 100%). Calcein injections 9 and 2 days prior to euthanasia labeled mineralizing surfaces for histomorphometric analyses 2 mm proximal to the tibio-fibular junction for mineralizing surface (%MS/BS), mineral apposition rate (MAR), and bone formation rate (BFR) on periosteal and endocortical surfaces. Results: After 4 weeks, only -25EA SED lost body mass (-11%); virtually all of this was fat mass. Periosteal BFR was 2 to 4 fold higher in EX rats vs. SED animals within each energy status group. The impact of EX on endocortical BFR was even greater (~5-fold increase) for all groups except in the -25 EA cohorts (-25 EA EX BFR ~ equal to -25EA SED BFR). Increases in BFR with EX were achieved by increases in both %MS/BS and MAR on both cortical surfaces. Conclusions: These data suggest that short-term graded reductions in EA do not inhibit BFR in SED animals nor the robust stimulation of BFR by moderately vigorous exercise training. The one exception observed was a suppression of the EX induced gain in endocortical BFR with the more stringent level of reduced EA. Whether this lack of effect of EA on BFR gains with EX persists with more chronic reductions in EA has yet to be determined. Funded by the Department of Defense #WSIXWH-06-1-047
Charge-transfer dynamics at the dye-semiconductor interface of photocathodes for solar energy applications
This article describes a comparison between the photophysical properties of two charge-transfer dyes adsorbed onto NiO via two different binding moieties. Transient spectroscopy measurements suggest that the structure of the anchoring group affects both the rate of charge recombination between the dye and NiO surface and the rate of dye regeneration by an iodide/triiodide redox couple. This is consistent with the performance of the dyes in p-type dye sensitised solar cells. A key finding was that the recombination rate differed in presence of the redox couple. This has important implications on the study of electron transfer at dye|semiconductor interfaces for solar energy applications
Cervical Screening and General Physical Examination Behaviors of Women Exposed In Utero to Diethylstilbestrol
Objective. To estimate whether women exposed in utero to diethylstilbestrol (DES) report receiving more cervical and general physical examinations compared to unexposed women.
Materials and Methods. 1994 Diethylstilbestrol Adenosis cohort data are used to assess the degree of recommended compliance of cervical screenings found in 3,140 DES-exposed and 826 unexposed women. Participants were enrolled at 4 sites: Houston, Boston, Rochester, and Los Angeles. Logistic regression modeling was used to analyze mailed questionnaire data, which included reported frequency over the preceding 5 years (1990-1994) of Papanicolaou smears and general physical examinations.
Results. Diethylstilbestrol-exposed women exceeded the recommended frequency of Papanicolaou smear screenings [adjusted odds ratio (aOR) = 2.15, 95% CI (confidence interval) = 1.60-2.88] compared to the unexposed. This association held among those without a history of cervical intraepithelial neoplasia (aOR = 1.88, 95% CI = 1.35-2.62). Diethylstilbestrol-exposed women exceeded annual recommendations for physical examinations (aOR = 2.27, 95% CI = 1.16-4.43) among women without a history of chronic disease when compared to unexposed women.
Conclusions. Most DES-exposed women are receiving cervical cancer screening at least at recommended intervals, but one third of the women are not receiving annual Papanicolaou smear examinations
Navigating to new frontiers in behavioral neuroscience: traditional neuropsychological tests predict human performance on a rodent-inspired radial-arm maze
We constructed an 11-arm, walk-through, human radial-arm maze (HRAM) as a translational instrument to compare existing methodology in the areas of rodent and human learning and memory research. The HRAM, utilized here, serves as an intermediary test between the classic rat radial-arm maze (RAM) and standard human neuropsychological and cognitive tests. We show that the HRAM is a useful instrument to examine working memory ability, explore the relationships between rodent and human memory and cognition models, and evaluate factors that contribute to human navigational ability. One-hundred-and-fifty-seven participants were tested on the HRAM, and scores were compared to performance on a standard cognitive battery focused on episodic memory, working memory capacity, and visuospatial ability. We found that errors on the HRAM increased as working memory demand became elevated, similar to the pattern typically seen in rodents, and that for this task, performance appears similar to Miller's classic description of a processing-inclusive human working memory capacity of 7 ± 2 items. Regression analysis revealed that measures of working memory capacity and visuospatial ability accounted for a large proportion of variance in HRAM scores, while measures of episodic memory and general intelligence did not serve as significant predictors of HRAM performance. We present the HRAM as a novel instrument for measuring navigational behavior in humans, as is traditionally done in basic science studies evaluating rodent learning and memory, thus providing a useful tool to help connect and translate between human and rodent models of cognitive functioning
Meta-analysis of genome-wide association studies of asthma in ethnically diverse North American populations.
Asthma is a common disease with a complex risk architecture including both genetic and environmental factors. We performed a meta-analysis of North American genome-wide association studies of asthma in 5,416 individuals with asthma (cases) including individuals of European American, African American or African Caribbean, and Latino ancestry, with replication in an additional 12,649 individuals from the same ethnic groups. We identified five susceptibility loci. Four were at previously reported loci on 17q21, near IL1RL1, TSLP and IL33, but we report for the first time, to our knowledge, that these loci are associated with asthma risk in three ethnic groups. In addition, we identified a new asthma susceptibility locus at PYHIN1, with the association being specific to individuals of African descent (P = 3.9 × 10(-9)). These results suggest that some asthma susceptibility loci are robust to differences in ancestry when sufficiently large samples sizes are investigated, and that ancestry-specific associations also contribute to the complex genetic architecture of asthma
Prospective comparison of switches in biomarker status between primary and recurrent breast cancer: the Breast Recurrence In Tissues Study (BRITS)
The Setpoint Study (ACTG A5217): Effect of Immediate Versus Deferred Antiretroviral Therapy on Virologic Set Point in Recently HIV-1–Infected Individuals
(See the editorial commentary by Tossonian and Conway, on pages 10–12.
Expression and Function of Ccbe1 in the Chick Early Cardiogenic Regions Are Required for Correct Heart Development
During the course of a differential screen to identify transcripts specific for chick heart/hemangioblast precursor cells, we have identified Ccbe1 (Collagen and calcium-binding EGF-like domain 1). While the importance of Ccbe1 for the development of the lymphatic system is now well demonstrated, its role in cardiac formation remained unknown. Here we show by whole-mount in situ hybridization analysis that cCcbe1 mRNA is initially detected in early cardiac progenitors of the two bilateral cardiogenic fields (HH4), and at later stages on the second heart field (HH9-18). Furthermore, cCcbe1 is expressed in multipotent and highly proliferative cardiac progenitors. We characterized the role of cCcbe1 during early cardiogenesis by performing functional studies. Upon morpholino-induced cCcbe1 knockdown, the chick embryos displayed heart malformations, which include aberrant fusion of the heart fields, leading to incomplete terminal differentiation of the cardiomyocytes. cCcbe1 overexpression also resulted in severe heart defects, including cardia bifida. Altogether, our data demonstrate that although cardiac progenitors cells are specified in cCcbe1 morphants, the migration and proliferation of cardiac precursors cells are impaired, suggesting that cCcbe1 is a key gene during early heart development.FCT [SFRH/BD/65628/2009, SFRH/BPD/86497/2012, SFRH/BPD/41081/2007]; F.C.T.B.I. fellowship [PTDC/SAU-BID/114902/ 2009]; FCT; Institute for Biotechnology Bioengineering (Centro Biomedicina Molecular e Celular (IBB/CBME), Laboratorio Associado (LA) in the frame of Project [PestOE/EQB/LA0023/2013]info:eu-repo/semantics/publishedVersio
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