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THE IMPORTANCE OF SEXUAL HEALTH DISCUSSIONS: DIFFERENCES IN HETEROSEXUAL MEN’S AND
WOMEN’S SEXUAL HEALTH COMMUNICATION WITH CLOSE FRIENDSDonna James, Matthew Mutchler Luis Juarez.
California State University Dominguez Hills, Carson, CA.
Although it is evident that discussing sexual health issues may lead to safer sex behaviors, there is limited insight about the differences between how heterosexual men and women discuss sexual health issues with friends. Our study was based on quantitative data collected through questionnaire surveys of college students regarding their level of sexual communication with their closest friend. We used a convenience sample made up of 250 participants, 60% of which were female and 40% were male. The race/ethnicity of the participant sample was 45.2% Hispanic, 36.4% African American, 11.6% White, 6% Asian-Pacific Islander, 2.8% Native American, and 1.6% other. The age range of participants was 18-21 = 30.8%, 22-25 = 32.8%, 26-30 = 18.4%, 31-40 = 7.6%, 41-50 = 6.8%, 51-60 = 3.2%, and 61 or older = 0.4%. Our analyses of the data demonstrated that women were more likely to discuss several aspects of
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BIO/AGR/ENV LIFE SCIENCES
BIOCHEMISTRY/BIOPHYSICSBallroom C - 122
BIOCOMPATIBILITY STUDIES OF PRECIOUS METAL NANOPARTICLES EVALUATED BY IN VITRO
CYTOTOXICITY ASSAYS USING LIVER AND BREAST CANCER CELL LINESM. Esther Salinas, Jason Parsons.
University of Texas-Pan American, Edinburg, TX.
Silver, gold, and palladium nanoparticles (NPs) are nanotechnological products studied for the treatment of cancer and targeted drug delivery. In the present study, gold, palladium, and silver NPs were synthesized by chemically reducing potassium tetrachloroaurate (III) hydrate, potassium tetrabromoaurate (III) dihydrate, potassium tetrachloropalladate (II), and silver nitrate. The synthesis of the NPs was performed using either trisodium citrate or sodium borohydride. The sodium borohydride-synthesized nanomaterials were stabilized using cetyltrimethylammonium bromide (CTAB). NPs were tested in vitro for toxicity assessment in cellular environments.
Hepa-1c1c7 from mouse hepatoma, HepG2 from human hepatocellular carcinoma, and MCF7 from human adenocarcinoma were treated with stabilized NPs and nonstabilized NPs over a range of doses (10 to 160 μM). The toxicity of the NPs was evaluated by measuring changes in cellular morphology via TEM imaging and metabolic activity via MTT cytotoxicity assay. Our data suggests that the cytotoxicity of NPs changes with nanoparticles’ synthesis methods with the 2 stabilizing agents and cell type. Results of these studies will be presented.
Ballroom C - 66 MF3:ND3+ (M=LA,GD,Y) NANOPARTICLES FOR OPTICAL AND MAGNETIC IMAGING L. Chris Mimun1, G. Ajithkumar1, Brian Yust1, Madhab Pokhrel1, Zakary Elliott1, Francisco Pedraza III1, Ashish Dhanale1, Ai-Ling Lin2, Liang Tang1 Dhiraj Sardar1.
University of Texas at San Antonio, San Antonio, TX, 2Barshop Institute of Cellular & Structural Biology, University of 1 Texas Health Science Center, San Antonio, TX.
Near infrared light (NIR)-based detection and therapy is well known in the biomedical industry. In this project, we are proposing the development of infrared-based magnetic nanoparticles (NP) for various biophotonics applications such as optical imaging that uses the low attenuation of biological tissues within the NIR window of interest and magnetic resonance imaging (MRI), that uses the magnetic properties of Gd. Halides such as MF3 (M=La, Gd, and
Y) were doped with an infrared-active rare earth ion, Nd3+. Synthesis conditions have been optimized for obtaining the brightest phosphor with a size of 50 nm. Characterizations of the NPs were done to explore the excitation and emission properties, crystal structure, TEM images, and magnetization properties. Toxicity studies of the synthesized NPs were also carried out to determine the viability and cytotoxicity at different concentrations. Since bioimaging is one of the key features of using these infrared-based magnetic nanoparticles, confocal images of cells have been obtained where the NPs were incubated with cells for 24 hrs. Our future goal is to use the properly optimized phosphors for real-time imaging using an IR camera as well as MRI T1 studies in the future. [This research was partially funded by NIGMS MBRS-RISE GM060655 and by the National Science Foundation Partnerships for Graduate Poster Research and Education in Materials (NSF-PREM) grant N0-DMR-0934218.] Ballroom C – 22
SYNTHESIS AND CHARACTERIZATION OF A THIOL-BASED HDAC INHIBITOR
DePaul University, Chicago, IL.
Histone deacetylase (HDAC) is an enzyme involved in histone modification resulting in changes in gene expression.
All NAD+-independent HDACs deacetylate lysine residues on histones and contain a catalytic zinc ion in their active sites. HDAC inhibitors are appealing anticancer agents because they hinder the formation of tumors, prevent cell proliferation, and induce terminal differentiation of tumor cells. However, they have been problematic for their off-target effects as well as poor bioavailability. Thiol-based HDAC inhibitors are potent, metabolically stable, small molecules
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that may be able to combat some of these issues. The thiol moiety of these inhibitors functions by coordinating zinc ions, preventing it from initiating catalysis. In this work, 7-mercapto-N-(4-phenyl-2-thiazolyl)hexanamide was synthesized, purified, and characterized. Its binding energetics with zinc were analyzed by isothermal titration calorimetry (ITC). Preliminary ITC data indicate complications due to sulfhydryl group oxidation in solution, which is mitigated by zinc chelation. Namely, we see much more oxidation occurring in control runs where the HDAC inhibitor is titrated into a buffer without zinc. Efforts are under way to select solution conditions that minimize oxidation, thus increasing the accuracy of resulting binding parameters. In summary, a novel HDAC inhibitor has been synthesized.
Through investigating binding energetics with zinc, information is obtained regarding the significance of metal chelation on HDAC inhibition, furthering the development of antitumor agents.
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ENGINEERING HIGH-AFFINITY HUMAN SINGLE-CHAIN T-CELL RECEPTORS AGAINST CANCER ANTIGENSSheena Smith1, Daniel Sommermeyer2, Thomas Schmitt3, Dolores Schendel4, Helga Bernhard5, Kurt Piepenbrink6, Brian Baker6, Thomas Blankenstein2, Wolfgang Uckert2, Philip Greenberg3, David Kranz1.
University of Illinois at Urbana-Champaign, Urbana, IL, 2Max-Delbrück-Center, Berlin, DE, 3University of Washington, 1 Seattle, WA, 4Institute for Molecular Immunology, Helmholtz Center, Munich, DE, 5Klinikum Darmstadt, Darmstadt, DE, 6Notre Dame University, South Bend, IN.
Single-chain T-cell receptors consisting of 2 linked variable regions (Valpha and Vbeta, referred to as scTv) provide a useful alternative engineering format to single-chain antibody fragments (scFv). Previously, we described the engineering of 2 high affinity human T-cell receptors (TCRs) in which the usage of the highly stable Valpha2 region, when properly paired with different Vbeta regions, allowed the TCR to be expressed on the surface of yeast as an scTv and correlated with the ability to express soluble scTv fragments in E. coli. In this study, a wild-type HLA-A2restricted TCR specific for melanoma antigen MART1/Melan-A, called INRI-T1, and a wild-type TCR specific for Wilm’s tumor antigen, called WT1 P22, which naturally use the highly stable Valpha2 region, were engineered for high affinity against their respective peptide antigens via yeast display and fluorescence-activated cell sorting. Alanine mutations of various CDR residues demonstrated the key role of particular residues in contacting the alpha helices of HLA-A2. In addition, we have generated a single TCR platform for yeast display-based engineering of designer TCRs with specificities for diverse peptide antigens. This approach would avoid the need to isolate T-cell clones against each peptide antigen and the subsequent characterization of the TCR genes and products.
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RARE-EARTH-DOPED, UPCONVERTING PARTICLES FOR BIO IMAGING APPLICATIONMadhab Pokhrel, Dhiraj Sardar, Ajith Kumar.
University of Texas at San Antonio, San Antonio, TX.
Trivalent, rare-earth ions, especially erbium (Er3+) and ytterbium (Yb3+), codoped in Y2O2S nanoparticles, are known for their extraordinary spectroscopic properties. A thorough optical characterization, including the absolute upconversion quantum yield (QY) decay time measurement, is of critical importance in evaluating their potential for bioimaging.
In this paper, we will be presenting measured absolute upconversion QYs for Yb3+ and Er3+ doped in Y2O2S at 980 excitation at various power densities. Comparison of absolute QYs for different concentrations of Yb3+ and Er3+ doped in Y2O2S will be made for all the upconversion emissions with respect to the reported most efficient upconverting phosphor, NaYF4, doped with 20% Yb3+ and 2% Er3+. Furthermore, applications of these nanophosphors in bioimaging will be explored, depending on the measured absolute upconversion quantum yields and decay time. In addition, preliminary results on in vitro imaging using upconverting nanoparticles as a contrast agent will be reported.
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HYBRID INVERSE PROBLEMS AND MEDICAL IMAGINGCarlos Montalto, Plamen Stefanov.
Purdue University, West Lafayette, IN.
Couple-physics inverse problems or hybrid inverse problems are research areas that are interested in developing the mathematical framework for medical imaging modalities that combine the best imaging properties of different types of waves (e.g., optical waves, electrical waves, pressure waves, magnetic waves, and shear waves, etc).
In some applications of non-invasive medical imaging modalities (e.g., cancer detection), there is a need for high contrast and high resolution images; high-contrast contrast discriminates between healthy and non-healthy tissue whereas high resolution is important to detect anomalies at early stages. Some current methodologies (e.g, electrical
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impedance tomography, optical tomography, ultrasound, and magnetic resonance) focus only on a particular type of wave that can either recover high resolution or high contrast, but not both with the required accuracy. The aim of hybrid inverse problems is to couple the physics of each wave to benefit from the imaging advantages of each one.
Three examples of this physical coupling are 1) ultrasound modulated electrical impedance tomography (UMEIT),
2) magnetic resonance electrical impedance tomography (MREIT), and 3) ultrasound modulated optical tomography (UMOT). In this work, we develop a general approach to prove stability in recovering the conductivity for the nonlinear second step of this hybrid inverse problem. Our data are internal functionals that are reconstructed from boundary measurements in a first step of the process. We prove Holder conditional stability for the non-linear problem of recovering the internal conductivity from these internal measurements.
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CHARACTERIZATION OF OXYLIPIN SIGNATURE IN LIPID TRANSFER PROTEIN MUTANTS OF ARABIDOPSISTHALIANA Charmaine Fay Soco, Robert Luis Vellanoweth.
California State University, Los Angeles, Los Angeles, CA.
Lipid transfer proteins (LTPs) exist in many animal tissues as well as in some fungi and plants. In vitro, LTPs are known for extracellular transport of lipids such as phospholipids, cholesterol, and gangliosides. LTPs constitute a large gene family and are ubiquitous in higher plants which indicate diverse physiological functions. In plants, LTPs are subdivided into two families, both of which have the common characteristic of a hydrophobic cavity for binding lipids. LTPs are important in cellular signaling, antimicrobial activity, and survival in plants. Studies on Arabidopsis thaliana have shown expression of LTPs in siliques, possibly to mediate transfer of lipids and other metabolites from seeds to other plant organs. In our lab, an LTP gene knockdown mutant of Arabidopsis thaliana showed a prolonged reproductive stage compared to the wild type. This led us to hypothesize that LTPs shuttle signaling molecules from seeds to meristems, without an apparent perennial phenotype being observed in the mutant. Interestingly, oxygenated fatty acids, collectively known as oxylipins, are known to regulate plant cell death. Oxylipins are present in seeds of Arabidopsis thaliana. Our aim is to characterize oxylpin differences in wild-type and LTP mutant seeds of Arabidopsis thaliana through analytical methods. Liquid chromatography-mass spectrometry (LC/MS) will identify similarities and deviations in oxylipin signatures between the seed types. The result of this study will demonstrate any association between oxylipins as regulators of plant cell death and lipid transfer proteins as the mode of transport for those signaling molecules.
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INVESTIGATING THE ROLES OF EIF4F AND EIFISO4F IN ARABIDOPSIS THALIANANicola Cole, Karen Browning.
University of Texas at Austin, Austin, TX.