Spectroscopic observation of nitrogen anions N(-) in solid matrices

Analysis of old and recent experiments on thermoluminescence of cryocrystals and nanoclusters of N2, Ne, Ar, and Kr containing stabilized nitrogen atoms, suggests that the so-called γ-line may correspond to the bound-bound transition (1)D-(3)P of nitrogen anions N(-) formed in solids by the association of delocalized electrons and metastable nitrogen atoms N((2)D). The recent observations of the γ-line were accompanied by simultaneous luminescence of metastable nitrogen N((2)D) atoms and exoelectron emission. The fine structure of the γ-line at 793 nm has been experimentally observed and investigated for the first time.

Assessing vascular effects of adding bevacizumab to neoadjuvant chemotherapy in osteosarcoma using DCE-MRI

BACKGROUND

The purpose of this study was to assess the impact of bevacizumab alone and in combination with cytotoxic therapy on tumour vasculature in osteosarcoma (OS) using DCE-MRI.

METHODS

Six DCE-MRI and three (18)F-FDG PET examinations were scheduled in 42 subjects with newly diagnosed OS to monitor the response to antiangiogenic therapy alone and in combination with cytotoxic therapy before definitive surgery (week 10). Serial DCE-MRI parameters (K(trans), v(p), and v(e)) were examined for correlation with FDG-PET (SUV(max)) and association with drug exposure, and evaluated with clinical outcome.

RESULTS

K(trans) (P=0.041) and v(p) (P=0.001) significantly dropped from baseline at 24 h after the first dose of bevacizumab alone, but returned to baseline by 72 h. Greater exposure to bevacizumab was correlated with larger decreases in v(p) at day 5 (P=0.04) and week 10 (P=0.02). A lower K(trans) at week 10 was associated with greater percent necrosis (P=0.024) and longer event-free survival (P=0.034).

CONCLUSIONS

This is the first study to demonstrate significant changes of the plasma volume fraction and vascular leakage in OS with bevacizumab alone. The combination of demonstrated associations between drug exposure and imaging metrics, and imaging metrics and patient survival during neoadjuvant therapy, provides a compelling rationale for larger studies using DCE-MRI to assess vascular effects of therapy in OS.

Dynamic nuclear polarization of high-density atomic hydrogen in solid mixtures of molecular hydrogen isotopes

We report on magnetic resonance studies of high-density atomic hydrogen and deuterium in solid hydrogen matrices at temperatures below 1 K. Average concentrations of H atoms ≈3×10(19)  cm(-3) are obtained in chemical tunneling reactions of isotope exchange with D atoms. The products of these reactions are closely located pairs of H atoms near D2 molecules with strong exchange interactions. We discovered a dynamic nuclear polarization effect on H atoms created by pumping the center of the H electron spin resonance spectrum, similar to the Overhauser effect in metals. Our results indicate that H atoms may be arranged inside molecular matrices at separations equivalent to local concentrations of 2.6×10(21)  cm(-3). This opens up a way to build a metallic state of atomic hydrogen at zero pressure.

Experimental setup for investigation of nanoclusters at cryogenic temperatures by electron spin resonance and optical spectroscopies

We present the design and performance of an experimental setup for simultaneous electron spin resonance (ESR) and optical studies of nanoclusters with stabilized free radicals at cryogenic temperatures. A gas mixture of impurities and helium after passing through a RF discharge for dissociation of molecules is directed onto the surface of superfluid helium to form the nanoclusters of impurities. A specially designed ESR cavity operated in the TE011 mode allows optical access to the sample. The cavity is incorporated into a homemade insert which is placed inside a variable temperature insert of a Janis (4)He cryostat. The temperature range for sample investigation is 1.25-300 K. A Bruker EPR 300E and Andor 500i optical spectrograph incorporated with a Newton EMCCD camera are used for ESR and optical registration, respectively. The current experimental system makes it possible to study the ESR and optical spectra of impurity-helium condensates simultaneously. The setup allows a broad range of research at low temperatures including optically detected magnetic resonance, studies of chemical processes of the active species produced by photolysis in solid matrices, and investigations of nanoclusters produced by laser ablation in superfluid helium.

Experimental cell for molecular beam deposition and magnetic resonance studies of matrix isolated radicals at temperatures below 1 K

We present the design and performance of an experimental cell constructed for matrix isolation studies of H and D atoms in solid H2/D2 films, which are created by molecular beam deposition at temperatures below 1 K. The sample cell allows sensitive weighing of the films by a quartz microbalance (QM) and their studies by magnetic resonance techniques in a strong magnetic field of 4.6 T. We are able to regulate the deposition rate in the range from 0.01 to 10 molecular layers/s, and measure the thickness with ≈0.2 monolayer resolution. The upper QM electrode serves as a mirror for a 128 GHz Fabry-Perot resonator connected to an electron spin resonance (ESR) spectrometer. H and D atoms were created by RF discharge in situ in the sample cell, and characterized by ESR and electron-nuclear double resonance. From the magnetic resonance measurements we conclude that the films are smooth and provide homogeneous trapping conditions for embedded atoms. The current sample cell design also makes it possible to calibrate the ESR signal and estimate the average and local concentrations of H and D radicals in the film.

Luminescence of oxygen atoms stimulated by metastable helium at cryogenic temperatures

We present investigations of the afterglow of oxygen-helium gas mixtures at cryogenic temperatures. The cooling of a helium jet containing trace amounts of oxygen after passing through a radio frequency discharge zone led to the observation of strong emissions from atomic oxygen. The effect results from the increasing efficiency of energy transfer from metastable helium atoms and molecules to oxygen impurities in the cold dense helium vapor. This effect might find an application for the detection of small quantities of the impurities in helium gas.

P4-07-03: Identification of Triple-Negative Primary Breast Cancer Xenograft Models with High Numbers of Circulating and Disseminated Tumor Cells

Background: Primary breast cancer xenografts, in which tumors are grown directly from patients and which maintain their original genotype and phenotype, have the potential to facilitate the study of tumor biology and progression. These models can also be instrumental in the discovery of novel therapeutic targets especially for the triple-negative (ER-, PR- and HER2−negative, TN) breast cancer. TN breast cancer is associated with high numbers of circulating and disseminated tumor cells (CTCs and DTCs), which predict poor outcome in patients and may play a role in tumor progression. However, isolation and detection of human CTCs and DTCs in these xenograft models have been challenging even with EpCAM-based enrichment methods. The goal of this study was to determine if CTCs and DTCs could be identified using human pan-CK staining in a panel of triple-negative primary breast cancer xenograft lines, which could then be employed to study the biology of these cells and to test novel therapies.

Methods: We screened 13 stable primary transplantable xenograft lines (1-6 mice per line), established by directly transplanting ethnically diverse triple-negative tumor samples into the epithelium-free mammary fat pads of SCID/Beige mice, for the presence of CTCs and DTCs. The triple-negative status was maintained in these xenograft lines over serial passages. To detect CTCs, peripheral blood mononuclear cells (PBMCs) were isolated from the blood collected from the inferior vena cava either by Ficoll gradient or RBC lysis, with a typical yield of 500,000 PBMCs in 500 μl of blood. Subsequently, PBMCs were immunostained for the presence of CTCs, which were defined as the cells positive for cytoplasmic human pan-cytokeratin staining and nuclear (DAPI/hematoxylin) counter stain. We also flushed the femurs and tibias of 7 xenograft lines to harvest bone marrow cells (BMCs) for the detection of DTCs using the same staining procedure. A xenograft line was considered positive for CTCs or DTCs if they were detected in at least 25% of mice. The presence of lung metastases was assessed in all the xenograft lines by histological examination.

Results: We detected CTCs (range: 1–128/20,000 PBMCs) in 6 out of 13 xenograft lines (46%) and DTCs (range: 1–21/20,000 BMCs) in 5 out of 7 (71%) lines. Interestingly, 4 of the 5 DTC-positive lines also had detectable CTCs. High numbers of CTCs (>20/20,000 PBMCs) were found in 3 xenograft lines, one of which also had high numbers of DTCs (>20/20,000 BMCs). No human pan-CK+ cells were detected in PBMCs and/or BMCs from 5 control mice without tumors. Among 13 xenograft lines, lung metastases were found in 5 lines (38%), of which 3 had detectable CTCs or DTCs. Of the 3 xenograft lines containing high CTCs and/or DTCs, 2 had lung metastases.

Conclusion: In summary, human pan-CK staining can effectively detect CTCs and DTCs in isolated PBMCs and BMCs of mice bearing triple-negative primary breast cancer xenografts. These xenograft lines with detectable CTCs and DTCs may represent a valuable preclinical model for detailed characterization of human CTCs and DTCs and for the discovery of new therapeutic targets for the triple-negative breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-07-03.

Antitumor effect of sFlt-1 gene therapy system mediated by Bifidobacterium Infantis on Lewis lung cancer in mice

Soluble fms-like tyrosine kinase receptor (sFlt-1) is a soluble form of extramembrane part of vascular endothelial growth factor receptor-1 (VEGFR-1) that has antitumor effects. Bifidobacterium Infantis is a kind of non-pathogenic and anaerobic bacteria that may have specific targeting property of hypoxic environment inside of solid tumors. The aim of this study was to construct Bifidobacterium Infantis-mediated sFlt-1 gene transferring system and investigate its antitumor effect on Lewis lung cancer (LLC) in mice. Our results demonstrated that the Bifidobacterium Infantis-mediated sFlt-1 gene transferring system was constructed successfully and the system could express sFlt-1 at the levels of gene and protein. This system could not only significantly inhibit growth of human umbilical vein endothelial cells induced by VEGF in vitro, but also inhibit the tumor growth and prolong survival time of LLC C57BL/6 mice safely. These data suggest that Bifidobacterium Infantis-mediated sFlt-1 gene transferring system presents a promising therapeutic approach for the treatment of cancer.

Dehydration and the dynamic dimensional changes within dentin and enamel

OBJECTIVES

The objectives of this study were to quantify the dimensional changes in dentin and enamel during dehydration, and to determine if there are differences between the responses of these tissues from young and old patients.

METHODS

Microscopic digital image correlation (DIC) was used to evaluate deformation of dentin and enamel as a function of water loss resulting from free convection in air. Dimensional changes within both tissues were quantified for two patient age groups (i.e. young 18< or =age< or =30 and old 50< or =age) and in two orthogonal directions (i.e. parallel and perpendicular to the prevailing structural feature (dentin tubules or enamel prisms)). The deformation histories were used to estimate effective dehydration coefficients that can be used in quantifying the strains induced by dehydration.

RESULTS

Both dentin and enamel underwent contraction with water loss, regardless of the patient age. There was no significant difference between responses of the two age groups or the two orthogonal directions. Over 1h of free convection, the average water loss in dentin was 6% and resulted in approximately 0.5% shrinkage. In the same time period the average water loss in the enamel was approximately 1% and resulted in 0.03% shrinkage. The estimated effective dehydration coefficients were -810microm/m/(% weight loss) and -50microm/m/(% weight loss) for dentin and enamel, respectively.

SIGNIFICANCE

The degree of deformation shrinkage resulting from dehydration is over a factor of magnitude larger in dentin than enamel.

Calculations of neutron and photon source terms and attenuation profiles for the generic design of the SPEAR3 storage ring shield

The FLUKA Monte Carlo particle generation and transport code was used to calculate shielding requirements for the 3 GeV, 500 mA SPEAR3 storage ring at the Stanford Synchrotron Radiation Laboratory. The photon and neutron dose equivalent source term data were simulated for a 3 GeV electron beam interacting with two typical target/shielding geometries in the ring. The targets simulated are a rectangular block of 0.7 cm thick copper and a 5 cm thick iron block, both tilted at 1 degree relative to the beam direction. Attenuation profiles for neutrons and photons in concrete and lead as a function of angle at different shield thicknesses were calculated. The first, second and equilibrium attenuation lengths of photons and neutrons in the shield materials are derived from the attenuation profiles. The source term data and the attenuation lengths were then used to evaluate the shielding requirements for the ratchet walls of all front-ends of the SPEAR3 storage ring.

CD14-mediated induction of interleukin-8 and monocyte chemoattractant protein-1 by a heat-resistant constituent of Porphyromonas gingivalis in endothelial cells

Viable and inactivated Porphyromonas gingivalis dose-dependently induced interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) secretion in human umbilical vein endothelial cells (HUVECs). The inactivated P. gingivalis, in comparison with viable bacteria, tended to enhance the production of both chemokines more strongly. The production of MCP-1 protein began increasing immediately after stimulation by P. gingivalis, and there was a nearly linear increase from 0 to 8 h of incubation, whereas IL-8 production showed a linear increase between 4 and 12 h of incubation. The IL-8 and MCP-1 mRNA expressions in HUVECs as determined by reverse transcriptase-polymerase chain reaction (RT-PCR) or Quantikine mRNA colorimetric quantification kits were found to be enhanced by P. gingivalis. Furthermore, the time courses of IL-8 and MCP-1 mRNA expressions were in accordance with those of protein production. Addition of polymyxin B or boiling did not weaken the stimulatory effect of P. gingivalis, which inhibited the effect of Escherichia coli lipopolysaccharide (E. coli LPS) and tumour necrosis factor-alpha (TNF-alpha), respectively. In contrast, the induction of IL-8 and MCP-1 by P. gingivalis was significantly reduced by anti-CD14 antibody. Our results suggest that some heat-stable component of P. gingivalis, including LPS, may be responsible for the induction of IL-8 and MCP-1 in HUVECs by a CD14-dependent mechanism. These effects might be involved in the accumulation and activation of neutrophils and monocytes at an early stage of the periodontal pathogenesis.

Constraints on cosmological parameters from the analysis of the cosmic lens all sky survey radio-selected gravitational lens statistics

We derive constraints on cosmological parameters and the properties of the lensing galaxies from gravitational lens statistics based on the final Cosmic Lens All Sky Survey data. For a flat universe with a classical cosmological constant, we find that the present matter fraction of the critical density is Omega(m)=0.31(+0.27)(-0.14) (68%)+0.12-0.10 (syst). For a flat universe with a constant equation of state for dark energy w=p(x)(pressure)/rho(x)(energy density), we find w<-0.55(+0.18)(-0.11) (68%).

A heat-stable component of Bartonella henselae upregulates intercellular adhesion molecule-1 expression on vascular endothelial cells

Bartonella henselae upregulated the expression of intercellular adhesion molecule-1 (ICAM-1) on human umbilical vein endothelial cells (HUVECs). The induction level of ICAM-1 depended on the inoculation bacterial dose. ICAM-1 expression began increasing 4 h after infection and reached a sustained peak beginning at 12 h after B. henselae infection; this time course was similar to that of lipopolysaccharide (LPS) of Escherichia coli. The stimulatory effect was abolished when live B. henselae were separated from HUVECs by a filter membrane. The nonpiliated strain, which is unable to invade endothelial cells, induced ICAM-1 expression to the same extent as the piliated strain. Inactivation of B. henselae by ultraviolet (UV) irradiation, heat (56 degrees C, 30 min), or sonication did not alter its stimulatory activity. Polymyxin B, which strongly inhibited the effect of LPS, did not exert any influence on the stimulatory activity of B. henselae. Furthermore, the effect of sonicated B. henselae was not inhibited even by boiling, which was also the case with LPS. Our data suggest that some heat-stable component of B. henselae binds to the endothelial cell surface, inducing ICAM-1 expression. Though the participation of LPS could not be completely ruled out, we suppose that some unidentified heat-stable proteins, lipids, or polysaccharides may be the stimulatory factor(s). The ability of B. henselae to enhance the expression of adhesion molecules on endothelial cells may be an important mechanism in the pathogenesis of B. henselae infection.

Inducible activation of c-Myc in adult myocardium in vivo provokes cardiac myocyte hypertrophy and reactivation of DNA synthesis

c-Myc, a protooncogene, mediates both proliferative and cellular growth in many cell types. Although not expressed in the adult heart under normal physiological conditions, Myc expression is rapidly upregulated in response to hypertrophic stimuli. Although Myc is capable of sustaining hyperplastic growth in fetal myocytes, the effects of its re-expression in adult postmitotic myocardium and its role in mediating cardiac hypertrophy are unknown. To determine the effects of de novo Myc activity in adult postmitotic myocardium in vivo, we created a novel transgenic model in which Myc is expressed and inducibly activated specifically in cardiac myocytes. Activation of Myc in adult myocardium was sufficient to reproduce the characteristic changes in myocyte size, protein synthesis, and cardiac-specific gene expression seen in cardiac hypertrophy. Despite the increased cardiac mass, left ventricular function remained normal. Activation of Myc also provoked cell cycle reentry in postmitotic myocytes, which led to increased nuclei per myocyte and DNA content per nuclei.