Laboratory tests of low density astrophysical nuclear equations of state

Clustering in low density nuclear matter has been investigated using the NIMROD multidetector at Texas A&M University. Thermal coalescence modes were employed to extract densities, ρ, and temperatures, T, for evolving systems formed in collisions of 47A MeV (40)Ar+(112)Sn, (124)Sn and (64)Zn+(112)Sn, (124)Sn. The yields of d, t, (3)He, and (4)He have been determined at ρ=0.002 to 0.03 nucleons/fm(3) and T=5 to 11 MeV. The experimentally derived equilibrium constants for α particle production are compared with those predicted by a number of astrophysical equations of state. The data provide important new constraints on the model calculations.

MDM2 regulates MYCN mRNA stabilization and translation in human neuroblastoma cells

The MYCN gene has a critical role in determining the clinical behavior of neuroblastoma. Although it is known that genomic amplification occurs in high-risk subsets, it remains unclear how MYCN expression is regulated in the pathogenesis of neuroblastomas. Here, we report that MYCN expression was regulated by the oncoprotein MDM2 at the post-transcriptional level and was associated with neuroblastoma cell growth. Increasing MDM2 by ectopic overexpression in the cytoplasm enhanced both mRNA and protein expression of MYCN. Mechanistic studies found that the C-terminal RING domain of the MDM2 protein bound to the MYCN mRNA's AREs within the 3'UTR and increased MYCN 3'UTR-mediated mRNA stability and translation. Conversely, MDM2 silencing by specific siRNA rendered the MYCN mRNA unstable and reduced the abundance of the MYCN protein in MYCN-amplified neuroblastoma cell lines. Importantly, this MDM2 silencing resulted in a remarkable inhibition of neuroblastoma cell growth and induction of cell death through a p53-independent pathway. Our results indicate that MDM2 has a p53-independent role in the regulation of both MYCN mRNA stabilization and its translation, suggesting that MDM2-mediated MYCN expression is one mechanism associated with growth of MYCN-associated neuroblastoma and disease progression.

New precision limit on the strange vector form factors of the proton

The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624  GeV2 and beam energy E(b) = 3.48  GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.

Particle-yield modification in jetlike azimuthal dihadron correlations in Pb-Pb collisions at √s(NN)=2.76 TeV

The yield of charged particles associated with high-p(t) trigger particles (8<p(t)<15 GeV/c) is measured with the ALICE detector in Pb-Pb collisions at √s(NN)=2.76 TeV relative to proton-proton collisions at the same energy. The conditional per-trigger yields are extracted from the narrow jetlike correlation peaks in azimuthal dihadron correlations. In the 5% most central collisions, we observe that the yield of associated charged particles with transverse momenta p(t)>3 GeV/c on the away side drops to about 60% of that observed in pp collisions, while on the near side a moderate enhancement of 20%-30% is found.

Bioequivalence evaluation of 2 tablet formulations of entecavir in healthy chinese volunteers: a single-dose, randomized-sequence, open-label crossover study

A randomized, 2-way crossover study was conducted in healthy Chinese male volunteers to evaluate the bioequivalence of a new generic formulation of entecavir (CAS 142217-69-4) tablets (test) and the available branded formulation (reference) to meet the requirements for marketing the test product in China. Test and reference tablets were administered as a single dose on 2 treatment days separated by a 2-week washout period. Blood samples were collected for a period of 24 h following drug administration. Plasma concentration of entecavir was determined by a liquid chromatography-tandem mass spectrometry (LC/MS/MS) method. Pharmacokinetic parameters were calculated using a noncompartmental model. Bioequivalence was determined by calculating 90% CIs for the ratios of Cmax, AUC0-t and AUC0-∞ values for the test and reference products. Tolerability was assessed by monitoring vital signs, laboratory tests and interviews with the volunteers before administration and every 2 h during the study. The 90% CIs of entecavir for Cmax, AUC0-t and AUC0-∞ were 95.2-106.9%, 98.4-104.6% and 97.3-104.4%, respectively, which fell within the interval of 80-125%. No clinically important adverse effects were reported. These results suggested that the test formulation of entecavir tablets met the regulatory criterion for bioequivalence to the reference formulation.

J/ψ polarization in pp collisions at √s=7 TeV

The ALICE Collaboration has studied J/ψ production in pp collisions at √s=7 TeV at the LHC through its muon pair decay. The polar and azimuthal angle distributions of the decay muons were measured, and results on the J/ψ polarization parameters λ(θ) and λ(φ) were obtained. The study was performed in the kinematic region 2.5<y<4, 2<p(t)<8 GeV/c, in the helicity and Collins-Soper reference frames. In both frames, the polarization parameters are compatible with zero, within uncertainties.

Experimental determination of in-medium cluster binding energies and Mott points in nuclear matter

In-medium binding energies and Mott points for d, t, 3He and α clusters in low-density nuclear matter have been determined at specific combinations of temperature and density in low-density nuclear matter produced in collisions of 47A MeV 40Ar and 64Zn projectiles with 112Sn and 124Sn target nuclei. The experimentally derived values of the in-medium modified binding energies are in good agreement with recent theoretical predictions based upon the implementation of Pauli blocking effects in a quantum statistical approach.

Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4<Q{2}<2.7 GeV{2}

We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16<x<0.35 with 1.4<Q{2}<2.7  GeV{2}. The corresponding neutron A{LT} asymmetries were extracted from the measured {3}He asymmetries and proton over {3}He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g{1T}{q} and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π{-} production on {3}He and the neutron, while our π{+} asymmetries are consistent with zero.

Substituted zinc phthalocyanine as an antimicrobial photosensitizer for periodontitis treatment

In the last decades the worldwide rise in antibiotic resistance has intensified the development of new antimicrobial agents. Photodynamic antimicrobial chemotherapy (PACT) has been used successfully to inactivate bacteria. We herein report a new zinc phthalocyanine based photosensitizer conjugated with polylysine moiety ( ZnPc-PL ). This photosensitizer significantly inactivated Porphyromonas gingivalis, the primary pathogenic bacteria responsible for periodontitis. No obvious phototoxicity was found to either mammalian bone marrow stromal cells (BMSC) or human periodontal ligament cells (HPDLC), indicating the high selectivity of ZnPc -PL toward bacteria. Furthermore, we established an experimental periodontitis model on beagle dogs to test the antimicrobial efficacy in vivo. The amount of gingival crevicular fluid (GCF) and the activity of crevicular fluid aspartate aminotransferase (AST) were monitored and were found to reduce significantly in the ZnPc-PL treated group compared to the controls (laser only and no treatment). In addition, PACT with ZnPc -PL caused a reduction in the bacterial burden by 100-fold compared to controls. Taken together, these findings suggest ZnPc-PL is a promising antimicrobial photosensitizer for the treatment of periodontal diseases.

Genetic polymorphisms of VKORC1, CYP2C9, CYP4F2 in Bai, Tibetan Chinese

BACKGROUND

VKORC1, CYP2C9 and CYP4F2 are three critical genes associated with inter-individual variation of warfarin dose. Many dosing algorithms containing these gene polymorphisms and demographic characteristics have been set up for better use of warfarin. However, with distinct gene mutation frequencies among different ethnics, dosing algorithms differ greatly. For Chinese, related research just concentrate on Han Chinese, ignoring other Chinese ethnicities. This study aims to detect the popular polymorphisms in these three critical genes in Bai, Tibetan Chinese, to start the exploration of better use of warfarin in Chinese minorities.

METHODS

PCR-based methods were used to analyze VKORC1 3673G > A, CYP2C9*3, CYP4F2 rs2108622 C > T in Han, Bai and Tibetan Chinese.

RESULTS

The differences among the mutation frequencies of the studied genes in three ethnicities were not statistically significant. The frequency of A-allele of VKORC1 3673G > A was 92.8%, 90.2%, 90.8% in Bai, Tibetan, Han Chinese, respectively. The frequency of *3-allele in CYP2C9*3 was low in Bai (4.5%), Tibetan (2.8%) and Han Chinese (4.6%). Approximately one fourth of each ethnic had the mutant T-allele of CYP4F2 rs108622. However, Bai Chinese got statistically higher A-allele frequency of VKORC1 3673G > A than previously studied Han Chinese did.

CONCLUSIONS

Bai Chinese got significant higher A-allele frequency of VKORC1 3673G > A.

Amine-functionalized lanthanide-doped KGdF4 nanocrystals as potential optical/magnetic multimodal bioprobes

Amine-functionalized lanthanide-doped KGdF(4) nanocrystals, synthesized via a facile one-step solvothermal route by employing polyethylenimine as the surfactant and capping ligand, have been demonstrated to be sensitive time-resolved FRET bioprobes to detect a trace amount of biomolecules such as avidin at a concentration of 5.5 nM and to be potential T(1)-MRI contrast agents due to a large longitudinal relaxivity of Gd(3+) (5.86 S(-1)·mM(-1) per Gd ion and 3.99 × 10(5) S(-1)·mM(-1) per nanocrystal).

P3-08-03: Exercise Increases Soluble Vascular Endothelial Growth Factor Receptor-1 (sFlt-1) in the Circulation of Adult Women

Background: Physical inactivity increases the risk of several different cancers, including breast cancer. Soluble fms-like tyrosine kinase-1 (sFlt-1) is an extra-cellular Ig-like domain of the VEGF receptor-1 that is released into the extracellular space and circulation where it inhibits the activities of VEGF. Over-expression of sFlt-1 has been shown to inhibit ovarian tumor growth in gene therapy experiments. The present study tests the hypothesis that exercise can increase sFlt-1 in the circulation of adult women.

Material and Methods: 63 African American and Caucasian adult woman volunteers aged 18–44 were enrolled into a prospective exercise study. All the participants walked on a treadmill for 30 minutes at a moderate intensity (40-60% heart rate reserve), and oxygen consumption (VO2) was quantified by utilizing a metabolic cart. Blood samples were collected before and immediately after exercise. The exercise test was conducted between the first and seventh day of the participant's menstrual cycle. The plasma concentrations of sFlt-1, unbound VEGF, and endostatin were measured using ELISA kits from R and D Systems.

Results: Plasma levels of sFlt-1 were 67.8±3.7 pg/ml immediately after exercise (30 minutes), significantly higher than basal levels of 54.5±3.3 pg/ml before exercise (P&lt;0.01; n=63). The % increase in sFlt-1 levels before and after exercise in adult women was 54%. There was no significant difference in the % increase of sFlt-1 levels between African American and Caucasian groups (P=0.5334). There was no significant difference in plasma levels of endostatin before (92.4±4.4 ng/ml) and immediately after (93.8±4.4 ng/ml; P=0.8216) exercise. The basal plasma levels of unbound VEGF (21.5±4.3 pg/ml) ware similar to the plasma levels of VEGF (22.5±4.6 pg/ml; P=0.8652) immediately after exercise.

Discussion: We previously reported that plasma levels of sFlt-1 significantly increased 30 minutes after exercise in adult men, in which plasma levels of unbound-VEGF significantly decreased and plasma levels of endostatin significantly increased 2 hours after exercise. Until now, there has been no data on whether exercise increases plasma sFlt-1 levels in women. Our study is the first to show that exercise in adult women significantly increases plasma levels of sFlt-1. VEGF pathways have both autocrine and paracrine effects for promoting breast cancer progression. Previous studies have demonstrated that sFlt-1 inhibits the activities of VEGF and suppresses ovarian tumor growth in mice. Exercise-induced plasma levels of sFlt-1 could be an important clinical biomarker to explore the mechanisms of exercise training in reducing breast cancer progression. The sFtl-1 is produced in the microvascular and macrovascular endothelial cells that exist throughout the skeletal muscle tissues. It is therefore plausible that release of sFlt-1 from the skeletal muscles into the circulation might be due to exercise-dependent reductions in oxygen tension in the skeletal muscle. In future studies, we will determine whether sFlt-1 can be released directly from the exercised muscle.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-08-03.

P5-13-17: Multigene Signature Assays in Patients with Early-Stage Breast Cancer (ESBC) Receiving Neoadjuvant Chemotherapy: An NCI-Funded Systematic Review and Evidence Summary of Predictive Performance

Background: A comprehensive literature search and evidence synthesis of multigene signatures predictive of response to systemic chemotherapy in patients with breast cancer was initiated as a part of an NCI-funded program on Comparative Effectiveness Research.

Methods: Validation studies were sought of multigene signatures for prediction of chemotherapy response (favorable vs unfavorable) in ESBC patient cohorts different from those used for signature development. Pooled estimates [±95% CI] of assay performance for predicting clinical outcome included sensitivity, specificity, likelihood ratio, predictive value (PV) and predictive odds ratio (POR) utilizing mixed effects models based on the method of Mantel-Haenszel. Exploratory metaregression analyses on log (POR) were also performed. Studies were classified by validation type including cell lines to patients, independent internal sample, random split sample, or external validation. Evidence for publication bias was assessed by Egger's regression intercept and Begg and Mazumdar's rank correction. Results: Dual-blind review of abstracts identified 33 studies of neoadjuvant chemotherapy response of which 29 stratified treatment response by signature classifier category. Classifier development was based on tumor response prediction in 20 studies, prognosis in 5, and molecular classification in 4. The Table shows assay performance measures overall and by study validation type. Assay performance based on the POR was positively associated with overall study quality (P=.015) and journal impact factor (P=.020). However, strong evidence for publication bias was observed based on both regression intercept (P&lt;.001) and rank correlation (P=.005). No significant differences in assay performance were noted for assays originally developed for response prediction (POR=5.3), prognosis (POR=6.6) or molecular classification (P=6.9) (P=.770).

P4-03-02: High Fat Diet-Induced Postmenopausal Obesity Promotes Tumor Angiogenesis and Breast Cancer Progression in Age-Relevant Ovariectomized Mice

Background: Obese postmenopausal women have 50% higher risk of breast cancer than non-obese women. The mechanisms of postmenopausal obesity-induced breast cancer are poorly understood due to lack of the established animal model that mimics postmenopausal obesity related to breast cancer progression.

Material and Methods: Using age-relevant C57BL/6 mice, this study determined whether postmenopausal obesity increases VEGF expression, tumor angiogenesis, and breast tumor growth. Ovariectomy (OVX) was performed in 12 sixty week-old female mice (life span is about 140 weeks), then followed by a low-fat (5%, LF, n=6) or a high-fat (60%, HF, n=6) diet for 12 weeks. In the 8th wk of the dietary program, 10^6 E0771 (mouse breast cancer) cells were injected in the left fourth mammary gland. Tumor size was monitored using dial calipers for 4 wk. Body weights were monitored weekly. At the end of the experiment, blood samples, visceral fat, and tumors were collected for measuring VEGF expression using ELISA and intratumoral microvessel density (IMD) using CD31 immunochemistry.

Results: Body weight was significantly increased in OVX/HF mice, compared to OVX/LF group (55.3±1.7 vs. 41.5±1.5 g; P&lt;0.01). There was a two-fold increase in the ratio of visceral fat/BW in OVX/HF mice, compared to those in OVX/LF group (0.062±0.005 vs. 0.032±0.003; P&lt;0.01). Postmenopausal obesity significantly increased breast tumor weight over the control (4.62±0.63 vs. 1.98±0.27 g; P&lt;0.01) and IMD (173±3.7 vs. 139±4.3 IM#/mm^2; P&lt;0.01). Tumor VEGF levels were higher in OVX/HF mice, compared to OVX/LF group (73.3±3.8 vs. 49.5±4.3 pg/mg protein; P&lt;0.01). Plasma VEGF levels (69±7.1 vs. 48±3.5 pg/ml) and visceral fat VEGF levels (424.4±39.5 vs. 208.5±22.4 pg/mg protein) were significantly increased in OVX/HF mice, compared to OVX/LF group, respectively (n=6; P&lt;0.01). Interestingly, adipose tissue primary culture showed that subcutaneous fat released more VEGF, compared to visceral fat (6.77±1.14 vs. 0.94±0.16 pg/mg tissue; n=6; P&lt;0.01). The abdominal subcutaneous fat expressed more VEGF proteins than visceral fat in OVX/HF mice (692±72 vs. 431±44 pg/mg protein; n=6; P&lt;0.01). There was a strong positive linear correlation between increased breast tumor weight and visceral fat weight in OVX mice (R2=0.7379; N=12; P&lt;0.01). However, there was no significant difference in heart, or kidney weight/body weight ratio between postmenopausal obesity (OVX/HF) mice and the control mice (OVX/LF).

Discussion: Our observations indicate that ovariectomy plus a high fat diet with the inoculation of E0771 (mouse ER+ breast cancer) cells in female wild type &gt;60 week old mice can mimic human obesity-induced postmenopausal breast cancer. The increased tumor angiogenesis in postmenopausal obese mice was correlated with increased breast tumor growth, adipose tissue mass, and adipokines such as VEGF. These findings support the hypothesis that postmenopausal obesity promotes tumor angiogenesis and breast cancer progression, possibly through increased adipose tissue mass and adipokines such as VEGF that could systemically and locally affect breast cancer progression.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-03-02.

P3-14-04: Assessment of Genomic Prognostic Signatures as Predictors of Response to Neoadjuvant Chemotherapy in Patients with Early Stage Breast Cancer

Background: Based on results from randomized clinical trials, adjuvant and neoadjuvant chemotherapy (NCT) strategies in early stage breast cancer patients (ESBC) achieve comparable long term results. Recently, a number of genomic signatures have been reported, distinguishing patients with low versus high risk of recurrence. While developed primarily as prognostic assays, these classifiers have also been proposed to be predictive of benefit from systemic chemotherapy. Neoadjuvant studies provide an opportunity to evaluate their predictive value for response to NCT.

Methods: A systematic review of gene expression profile studies in ESBC patients receiving chemotherapy was conducted. Medline search of original research articles of human studies published between January 2000 and February 2011 was based on key words and MeSH heading terms. Publications presenting outcomes for chemotherapy treated patients in groups stratified by multi-gene array signatures and utilizing a new independent cohort of patients compared to the original development cohort were selected. Information from eligible studies was extracted by dual abstraction. Reported results were synthesized into combined diagnostic odds ratio (DOR) using method of Mantel-Haenszel. This analysis is restricted to neoadjuvant studies investigating the association of genomic signature prognostic categories with objective tumor response to chemotherapy. Results: A total of 42 articles were eligible for data abstraction. Out of these, 6 publications evaluated response to NCT in good (low risk of recurrence) versus poor prognosis groups based on genomic prediction. Since two of the studies analyzed the same signature on a cohort with large overlap, only 5 studies were included in the final analysis, accounting for n=918 patients. Response consisted of pathologic complete response (pCR) in 3 studies, pCR or minimal residual disease (1 study), and clinical complete response (1 study). Prognostic genomic assays included Oncotype DX (1), MammaPrint (1), Genomic Grade Index (2) and PAM50 Risk of Relapse Score (1). Eight different chemotherapy regimens were utilized. The most common drugs were cyclophosphamide, anthracyclines, taxanes, and 5-fluorouracil. Across all genomic signatures, good prognosis patients, as defined by gene expression data, demonstrated consistently low rates of response to chemotherapy (median 3%, range 0–12%) compared to patients with less favorable prognosis (median 32%, range 19–43%). Odds ratio for response in poor versus good prognosis patients ranged from 3.9 to 21.7 with combined DOR= 6.6 (95% CI 3.9−11.3, P&lt;0.0001). No heterogeneity was determined across studies (P=0.4). The C-statistic estimating assay discriminatory ability was reported in 3 studies ranged from 0.72 to 0.78.

Conclusions: Across all genomic prognostic signatures reported, only a very small proportion of patients with signature predicted good prognosis achieved complete response to NCT. This suggests low sensitivity to chemotherapy among good prognosis patients, as determined by the prognostic genomic signatures. This further confirms the association between poor prognosis tumors and higher responsiveness to chemotherapy.

Funding: NCI: UC2CA14041-01

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-14-04.

A fluorescent fatty acid probe, DAUDA, selectively displaces two myristates bound in human serum albumin

11-(Dansylamino) undecanoic acid (DAUDA) is a dansyl-type fluorophore and has widely used as a probe to determine the binding site for human serum albumin (HSA). Here, we reported that structure of HSA-Myristate-DAUDA ternary complex and identified clearly the presence of two DAUDA molecules at fatty acid (FA) binding site 6 and 7 of HSA, thus showing these two sites are weak FA binding sites. This result also show that DAUDA is an appropriate probe for FA site 6 and 7 on HSA as previous studied, but not a good probe of FA binding site 1 that is likely bilirubin binding site on HSA.

Novel surface display system for heterogonous proteins on Lactobacillus plantarum

AIMS

To establish a novel cell surface display system that would enable the display of target proteins on Lactobacillus plantarum.

METHODS AND RESULTS

BlastP analysis of the amino acids sequence data revealed that the N-terminus of the putative muropeptidase MurO from L. plantarum contained two putative lysin motif (LysM) repeat regions, implying that the MurO was involved in bacterial cell wall binding. To investigate the potential of MurO for surface display, green fluorescent protein (GFP) was fused to MurO at its C-terminus and the resulting fusion protein was expressed in Escherichia coli. After being mixed with L. plantarum cells in vitro, GFP was successfully displayed on the surfaces of L. plantarum cells. Increases in the fluorescence intensities of chemically pretreated L. plantarum cells compared to those of nonpretreated cells suggested that the peptidoglycan was the binding ligand for MurO. SDS sensitivity assay showed that the GFP fluorescence intensity was reduced after being treated with SDS. To demonstrate the applicability of the MurO-mediated surface display system, β-galactosidase from Bifidobacterium bifidium, in place of GFP, was functionally displayed on the surface of L. plantarum cells via MurO.

CONCLUSIONS

The MurO was a novel anchor protein for constructing a surface display system for L. plantarum.

SIGNIFICANCE AND IMPACT OF STUDY

The success in surface display of GFP and β-galactosidase opened up the feasibility of employing the cell wall anchor of MurO for surface display in L. plantarum.