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.

[Use of microsatellites in zygosity diagnosis of twins]

OBJECTIVE

To diagnose zygosity of twins by microsatellite polymorphism.

METHODS

One hundred and eighty-four samples, including 69 pairs of twins with the same gender and 6 pairs of twins with different gender were recruited. Seventeen sib pairs were also collected for controls. Nine highly polymorphic microsatellite loci were amplified by polymerase chain reaction (PCR) using fluorescence-labeled primers and the products were sized by automated fragment analysis after electrophoresis and laser detection. Zygosity was diagnosed by comparing the concordance of the genotype of the 9 markers.

RESULTS

Sixty-three pairs of monozygotic (MZ) and 12 pairs of dizygotic (DZ) twins were assigned their zygosity by comparison of polymorphism of 9 microsatellite loci. Within each of the 63 monozygotic (MZ) pairs there was complete concordance. However, within each of the 12 dizygotic pairs and other 17 sib pairs, discordant loci were found. With five or six markers, the probability that any twin pair was MZ if all markers were concordant was 99% or 99.6%, respectively. With all the nine markers, the probability that any twin pair was MZ if all markers were concordant was 99.95%.

CONCLUSION

The technology of gene scan and genotyping provides a rapid and reliable approach to zygosity detection.

Cyclin A-dependent phosphorylation of the ETS-related protein, MEF, restricts its activity to the G1 phase of the cell cycle

MEF, a recently identified member of the E74 family of ETS-related transcription factors, is a strong transcriptional activator of cytokine gene expression. Using a green fluorescent protein gene reporter plasmid regulated by an MEF-responsive promoter, we determined that the transcriptional activity of MEF is largely restricted to the G1 phase of the cell cycle. MEF-dependent transcription was suppressed by the expression of cyclin A but not by cyclin D or cyclin E. This effect was due to the kinase activity generated by cyclin A expression, as co-expression of the cyclin-dependent kinase inhibitors p21 or p27, or a dominant negative form of CDK2 (DNK2), abrogated the reduction of MEF transcriptional activity by cyclin A. Cyclin A-CDK2 phosphorylated MEF protein in vitro more efficiently than cyclin D-CDK4 or cyclin E-CDK2, and phosphorylation of MEF by cyclin A-CDK2 reduced its ability to bind DNA. We determined one site of phosphorylation by cyclin A-CDK2 at the C terminus of MEF, using mass-spectrometry; mutation of three serine or threonine residues in this region significantly reduced phosphorylation of MEF by cyclin A and reduced cyclin A-mediated suppression of its transactivating activity. These amino acid substitutions also reduced the restriction of MEF activity to G1. Phosphorylation of MEF by the cyclin A-CDK2 complex controls its transcriptional activity during the cell cycle, establishing a novel link between the ETS family of proteins and the cell cycle machinery.

[Study on anticonvulsive effect of rhizoma pinelliae]

Anticonvulsive effect of water-soluble extract of rhizoma Pinelliae was studied. The result showed that the extract of rhizoma Pinelliae could remarkably inhibit the convulsion induced by strychnine and obviously reduce mortality rate in mice. But the extract could be destroyed easily by heat.

Optimal ECG trigger point in electron-beam CT studies: three methods for minimizing motion artifacts

RATIONALE AND OBJECTIVES

The authors hypothesized that electrocardiographic triggering near end systole could minimize motion artifacts in electron-beam computed tomography (CT) of the coronary artery.

MATERIALS AND METHODS

The study included 2,660 patients who underwent coronary artery calcium scanning with electron-beam CT. Trigger times were as follows: end of T wave, 120 to 25 msec before end of T wave, 25-50 msec after end of T wave, 40%, 45%, 50%, 55%, 60%, 70%, 75%, 80%, 90%, and 100% of R-R interval. The authors divided each group into seven subgroups according to heart rate. The percentages of cases with motion artifact in the right coronary artery were computed. Optimal trigger times were defined for each group, as well as for scan acquisitions of 250 and 200 msec.

RESULTS

The optimal trigger times were as follows for heart rates of less than 50, 51-60, 61-70, 71-80, 81-90, 91-100, and more than 100 beats per minute, respectively: for 100-msec scans, 359 (27% of the R-R interval), 228 (31%), 314 (34%), 304 (38%), 289 (41%), 283 (45%), and 274 msec (48%) after the R wave; for 250-msec scans, 840 (63%), 654 (60%), 240 (26%), 224 (28%), 219 (31%), 208 (33%), and 200 msec (35%) after the R wave; and for 200-msec scans, 722 (65%), 687 (63%), 249 (27%), 248 (31%), 244 (35%), 233 (37%), and 223 msec (39%) after the R wave.

CONCLUSION

The use of these new electrocardiographic triggers before end systole yielded the lowest percentage of motion artifacts (<3% across all heart rates), much lower than for conventional triggers (51% of cases with motion artifact for 80% trigger, P < .001).

Nuclear respiratory factors 1 and 2 are upregulated in hearts from copper-deficient rats

It is known that mitochondrial transcription factor A (mtTFA) plays a pivotal role in coordinating the expression of proteins in the nuclear and mitochondrial genomes as it pertains to mitochondrial biogenesis. Hearts from copper-deficient rats have elevated mtTFA levels compared to copper-adequate rats. This study evaluated whether two proteins that control activation of mtTFA by binding to its promotor, nuclear respiratory factors 1 (NRF-1) and 2 (NRF-2), are also upregulated prior to any upregulation of mtTFA. Long-Evans male rats were fed either copper-adequate or copper-deficient diets from weanling for periods of time up to 26 d. At d 26, mtTFA levels were elevated in the hearts from the copper-deficient rats, but not at earlier time points of 14, 18, and 22 d. However, NRF-1 and NRF-2 levels were increased at d 14 and 18, but not at the other two later time-points. These results revealed that the upregulation of mtTFA and mitochondrial biogenesis is preceded by upregulation of NRF-1 and NRF-2, which is consistent with the known molecular events controlling mitochondrial biogenesis in other systems.

Synthesis of solid-supported mirror-image sugars: a novel method for selecting receptors for cellular-surface carbohydrates

We introduced a novel method, through mirror-image phage display, for the identification of high-affinity D-peptides to target specific cell-surface carbohydrates. Both 3-deoxy-alpha-L-manno-2-octulosonic acid (L-KDO) and L-sialic acid and an L-sialo-disaccharide have been synthesized and attached to a solid support for selection of high-affinity peptide binders displayed on phages. Our initial studies in this effort produce single-chain Fab sequences and dodecapeptides that bind to sialic acid and KDO with nanomolar and high micromolar affinity.

Effect of electrocardiogram triggering on reproducibility of coronary artery calcium scoring

PURPOSE

To test the hypothesis that computed tomographic (CT) scanning during early rather than middle diastole can significantly reduce the interscan variability of coronary artery calcium (CAC) scores.

MATERIALS AND METHODS

Five hundred thirty-eight patients were initially enrolled; 282 of them were found to have CAC at electron-beam CT and underwent repeat scanning to measure interscan variability with different electrocardiogram (ECG) triggers. Eight patients were excluded owing to respiratory motion; thus, 274 asymptomatic patients were examined. Patients were randomly assigned to different ECG trigger interval groups: 40% (group 1), 50% (group 2), 60% (group 3), and 80% (group 4). Patients in whom more than one-third of sections had greater than 10% ECG trigger variability were classified in the untriggered group (group 5). Interscan variation was compared among all five groups.

RESULTS

Interscan variabilities in CAC groups 1-5 were 11.5%, 15.3%, 20.3%, 17.4%, and 33.1%, respectively, for total calcium area, and 15.0%, 23.3%, 25.6%, 24.0%, and 42.4%, respectively, for total calcium score. CAC score variability was reduced by 34%; and calcium area variability, by 38% in group 1, as compared with the reduced variabilities in group 4 (P <.01 for both measures). Breath holding was adequate in 812 cases, and ECG triggering was correct in 790 of cases.

CONCLUSION

Study results strongly support the use of an ECG trigger of 40% rather than 80% of the R-R interval in electron-beam CT calcium studies.