Biomedical subjects

Daniel Wang

Publications and source records attributed to Daniel Wang.

8 recordsLinked to original sources

PubMed2006

WormBase: new content and better access.

WormBase (http://wormbase.org), a model organism database for Caenorhabditis elegans and other related nematodes, continues to evolve and expand. Over the past year WormBase has added new data on C.elegans, including data on classical genetics, cell biology and functional genomics; expanded the annotation of closely related nematodes with a new genome browser for Caenorhabditis remanei; and deployed new hardware for stronger performance. Several existing datasets including phenotype descriptions and RNAi experiments have seen a large increase in new content. New datasets such as the C.remanei draft assembly and annotations, the Vancouver Fosmid library and TEC-RED 5' end sites are now available as well. Access to and searching WormBase has become more dependable and flexible via multiple mirror sites and indexing through Google.

Animals↗

PubMed2006

Co-expression of estrogen receptor-alpha and targets of estrogen receptor action in proliferating monkey mammary epithelial cells.

INTRODUCTION: Failure to detect co-expression of estrogen receptor-alpha (ERalpha) and proliferation 'markers' such as Ki67 in human mammary epithelium led to the view that estrogen acts indirectly to stimulate mammary epithelial proliferation. The mitotic index was so low in prior studies, however, that transient co-expression of ERalpha and Ki67 during the cell cycle could have been below detection limits. METHODS: Immunohistochemistry was used on mammary tissue sections from estrogen treated rhesus monkeys to investigate co-expression of ERalpha and the proliferation antigen Ki67. Using the same methods, we investigated the cell localization of proteins involved in estrogen-induced proliferation, including cyclin D1, stromal cell-derived factor (SDF)-1, and MYC. RESULTS: ERalpha was co-expressed with the proliferation marker Ki67 as well as with SDF-1, MYC and cyclin D1 in mammary epithelial cells from estrogen-treated monkeys. CONCLUSION: ERalpha is expressed in proliferating mammary epithelial cells together with the estrogen-induced proteins MYC, cyclin D1 and SDF-1, consistent with a direct mitogenic action by estrogen in primate mammary epithelium.

Animals↗

PubMed2006

WormBase: better software, richer content.

WormBase (http://wormbase.org), the public database for genomics and biology of Caenorhabditis elegans, has been restructured for stronger performance and expanded for richer biological content. Performance was improved by accelerating the loading of central data pages such as the omnibus Gene page, by rationalizing internal data structures and software for greater portability, and by making the Genome Browser highly customizable in how it views and exports genomic subsequences. Arbitrarily complex, user-specified queries are now possible through Textpresso (for all available literature) and through WormMart (for most genomic data). Biological content was enriched by reconciling all available cDNA and expressed sequence tag data with gene predictions, clarifying single nucleotide polymorphism and RNAi sites, and summarizing known functions for most genes studied in this organism.

Animals↗

PubMed2006

High-avidity antitumor T-cell generation by toll receptor 8-primed, myeloid- derived dendritic cells is mediated by IL-12 production.

BACKGROUND: High-level production of heterodimeric p70 interleukin (IL)-12 by myeloid-derived dendritic cells (DCs) requires 2 signals: interferon gamma (IFN-gamma) and a maturation signal provided by CD40 ligation (CD40L) or lipopolysaccharide (LPS). METHODS: In the current study we demonstrate that signaling through toll-like receptor (TLR) 8, but not TLR3, TLR2, or TLR4, provides a priming signal to myeloid-derived DC for high IL-12 p70 heterodimer production. RESULTS: All the TLR agonists induced maturation of DC as evidenced by increased expression of CD83, CD80, and CD86. Both IFN-gamma and TLR7/8 agonist R848 increased expression of TLR8 in immature monocyte-derived DCs. The combination of TLR7/8 agonist R848 and maturation signals LPS or CD40L induced high-level expression of IL-12p35 and p40 similar to that induced by IFN-gamma plus LPS. In contrast, receptor agonists specific for TLR7 did not prime for IL-12 production. The p70 IL-12 produced by the TLR8-primed DC polarized CD4+ T for Th1 cytokine production and induced CD8+ T cells, displaying high functional avidity with enhanced tumor cell recognition. CONCLUSIONS: The data suggest that toll 8 receptor agonists are useful for inducing type-1 polarized DCs for vaccine design in treating cancer and infectious disease.

Antigens, CD↗

PubMed2005

Determination of volatile organic compounds in different microenvironments by multibed adsorption and short-path thermal desorption followed by gas chromatographic-mass spectrometric analysis.

A multiphase assurance approach was developed for the accurate and precise determination of volatile organic compounds (VOCs) in different microenvironments. This approach includes (i) development of a method including adsorption of VOCs onto a multisorbent media followed by short-path thermal desorption (SPTD) pre-concentration and gas chromatography (GC) coupled to a mass spectrometry (MS) quantification, (ii) validation of the sampling and analytical method and (iii) validation of the data using a multidimensional procedure. Tenax TA and Carbopack B sorbent combinations were used to collect 102 individual VOCs ranging from C5 to C12. Method parameters including thermal desorption temperature, desorption time and cryofocusing temperature were optimized. The average recoveries and method detection limits (MDL) for the target analytes were in the range 80-100% and 0.01-0.14 ppbv, respectively. The method also showed good linearity (R2 > 0.99) and precision (<8%) values. Validation of the method was performed under real environmental conditions at a gas station, in an office and a residential household to examine the influence of variation in meteorological conditions such as temperature and relative humidity and a wide range of VOC concentrations. The sampling and analytical method resulted in successful determination of VOC in different microenvironments. Finally, validation of the data was performed by assessing fingerprint and time series plots and correlation matrices together with meteorological parameters such as mixing height, wind speed and temperature. The data validation procedure provided detection of both faulty data and air pollution episodes.

Adsorption↗

PubMed2005

Tau is hyperphosphorylated in the insulin-like growth factor-I null brain.

IGF action has been implicated in the promotion of oxidative stress and aging in invertebrate and murine models. However, some in vitro models suggest that IGF-I specifically prevents neuronal oxidative damage. To investigate whether IGF-I promotes or retards brain aging, we evaluated signs of oxidative stress and neuropathological aging in brains from 400-d-old Igf1-/- and wild-type (WT) mice. Lipofuscin pigment accumulation reflects oxidative stress and aging, but we found no difference in lipofuscin deposition in Igf1-/- and WT brains. Likewise, there was no apparent difference in accumulation of nitrotyrosine residues in Igf1-/- and WT brains, except for layer IV/V of the cerebral cortex, where these proteins were about 20% higher in the Igf1-/- brain (P = 0.03). We found no difference in the levels of oxidative stress-related enzymes, neuronal nitric oxide synthase, inducible nitric oxide synthase, and superoxide dismutase in Igf1-/- and WT brains. Tau is a microtubule-associated protein that causes the formation of neurofibrillary tangles and senile plaques as it becomes hyperphosphorylated in the aging brain. Tau phosphorylation was dramatically increased on two specific residues, Ser-396 and Ser-202, both glycogen synthase kinases target sites implicated in neurodegeneration. These observations indicate that IGF-I has a major role in regulating tau phosphorylation in the aging brain, whereas its role in promoting or preventing oxidative stress remains uncertain.

Aging↗

PubMed2005

A pilot controlled trial of topiramate for mania in children and adolescents with bipolar disorder.

OBJECTIVE: To assess the efficacy of topiramate monotherapy for acute mania in children and adolescents with bipolar disorder type I. METHOD: This double-blind, placebo-controlled study was discontinued early when adult mania trials with topiramate failed to show efficacy. Efficacy end points included the Young Mania Rating Scale (YMRS), Brief Psychiatric Rating Scale for Children, Children's Depression Rating Scale, Children's Global Assessment Scale, and Clinical Global Impressions-Improvement. RESULTS: Fifty-six children and adolescents (6-17 years) with a diagnosis of bipolar disorder type I received topiramate (n=29, 52%) or placebo (n=27, 48%). The only statistically significant differences in efficacy measures between treatment groups were the difference between slopes of the linear mean profiles of the YMRS (p=.003) using a post hoc repeated measures regression and the change in Brief Psychiatric Rating Scale for Children at day 28 (-14.9 versus-5.9, p=.048) using observed data. Adverse events with topiramate included decreased appetite, nausea, diarrhea, and paresthesia. CONCLUSIONS: Topiramate was well tolerated; however, the results are inconclusive because of premature termination resulting in a limited sample size. Adequately powered controlled trials are necessary to determine whether topiramate has efficacy in reducing symptoms of acute mania in children and adolescents.

Acute Disease↗

PubMedDate not supplied

Cutting on triangle mesh: local model-based haptic display for dental preparation surgery simulation.

A new method to realize stable and realistic cutting simulation using an impedance display haptic device and microcomputer is presented in this paper. Material removal or cutting simulation is a critical task in dental preparation surgery simulation. In this paper, a piecewise contact force model is proposed to approximately describe the cutting process. Challenging issues of minimizing the difference between the cutting simulation and haptic contact simulation are analyzed. The proposed contact-based simulation method is developed for a one-dimensional cutting task and can be expanded to three-dimensional cases. Local model-based multirate simulation cutting architecture is proposed and force control of the haptic device is decoupled from the cutting simulation loop, which can both ensure high fidelity of dynamical simulation as well as maintain stability of the haptic device. The cutting operation is realized using spherical and cylindrical shaped tools. An experiment based on the Phantom desktop proves that fidelity in one-dimensional cutting can be realized and stability in three-dimensional cutting can be ensured using the force-filtering method.

Computer Simulation↗