Centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV

The centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV is presented. The charged-particle density normalized per participating nucleon pair increases by about a factor of 2 from peripheral (70%-80%) to central (0%-5%) collisions. The centrality dependence is found to be similar to that observed at lower collision energies. The data are compared with models based on different mechanisms for particle production in nuclear collisions.

Elliptic flow of charged particles in Pb-Pb collisions at sqrt[S(NN)] = 2.76 TeV

We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at sqrt[S(NN)] =2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η|<0.8) and transverse momentum range 0.2<p t<5.0 GeV/c. The elliptic flow signal v₂, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 ± 0.002(stat) ± 0.003(syst) in the 40%-50% centrality class. The differential elliptic flow v₂ p t reaches a maximum of 0.2 near p t =3 GeV/c. Compared to RHIC Au-Au collisions at sqrt[S(NN)] 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.

Charged-particle multiplicity density at midrapidity in central Pb-Pb collisions at sqrt[S(NN)] = 2.76 TeV

The first measurement of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair √ S NN = 2.76 TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section, the pseudorapidity density of primary charged particles at midrapidity is 1584 ± 4(stat) ± 76(syst), which corresponds to 8.3 ± 0.4(syst) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at √ S NN = 2.76 TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.

Arrestin-1 expression level in rods: balancing functional performance and photoreceptor health

In rod photoreceptors, signaling persists as long as rhodopsin remains catalytically active. Phosphorylation by rhodopsin kinase followed by arrestin-1 binding completely deactivates rhodopsin. Timely termination prevents excessive signaling and ensures rapid recovery. Mouse rods express arrestin-1 and rhodopsin at ∼0.8:1 ratio, making arrestin-1 the second most abundant protein in the rod. The biological significance of wild type arrestin-1 expression level remains unclear. Here we investigated the effects of varying arrestin-1 expression on its intracellular distribution in dark-adapted photoreceptors, rod functional performance, recovery kinetics, and morphology. We found that rod outer segments isolated from dark-adapted animals expressing arrestin-1 at wild type or higher level contain much greater fraction of arrestin-1 than previously estimated, 15-25% of the total. The fraction of arrestin-1 residing in the outer segments (OS) in animals with low expression (4-12% of wild type) is much lower, 5-7% of the total. Only 4% of wild type arrestin-1 level in the outer segments was sufficient to maintain near-normal retinal morphology, whereas rapid recovery required at least ∼12%. Supra-physiological arrestin-1 expression improved light sensitivity and facilitated photoresponse recovery, but was detrimental for photoreceptor health, particularly in the peripheral retina. Thus, physiological level of arrestin-1 expression in rods reflects the balance between short-term functional performance of photoreceptors and their long-term health.

Preferences regarding genetic research results: comparing veterans and nonveterans responses

OBJECTIVE

Communicating genetic research results to participants presents ethical challenges. Our objectives were to examine participants' preferences in receiving future genetic research results and to compare preferences reported by veteran and nonveterans participants.

METHODS

Secondary analysis was performed on data collected in 2000-2004 from 1,575 consent forms signed by Mexican-American participants enrolled in 2 genetic family studies (GFS) in San Antonio: The Family Investigation of Nephropathy and Diabetes (FIND) and the Extended FIND (EFIND). The consent forms for these studies contained multiple-choice questions to examine participants' preferences about receiving their (1) clinical lab results and (2) future genetic research results. The FIND and EFIND databases had information on subjects' demographic characteristics and some selected clinical variables. We identified veterans using the Veterans Health Administration's (VHA's) centralized data repository. We compared veterans' and nonveterans' preferences using Student's t test for continuous variables and χ² test for discrete variables. A logistic regression analyzed subjects' preference for receiving their research results, controlling for other socio-demographic and clinical variables.

RESULTS

The sample included 275 (18%) veterans and 1,247 (82%) nonveterans. Our results indicated a strong desire among the majority of participants 1,445 (95%) in getting their clinical lab research results. Likewise, 93% expressed interest in being informed about their future genetic results. There was no significant difference in veterans' and nonveterans' preference to disclosure of the research results (χ² test; p > 0.05). Regression analysis showed no significant relationship (p = 0.449) between the outcome (receiving research results) and veterans' responses after controlling for demographics and educational levels.

CONCLUSION

Participants believed they would prefer receiving their genetic research results. Veterans are similar to nonveterans in their preferences. Offering genetic research results to participants should be based on well defined and structured plans to enhance interpretation of genetic data.

Midrapidity antiproton-to-proton ratio in pp collisons at sqrt[s]=0.9 and 7 TeV measured by the ALICE experiment

The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at sqrt[s]=0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45<p_{t}<1.05  GeV/c and rapidity |y|<0.5. The ratio is measured to be R_{|y|<0.5}=0.957±0.006(stat)±0.014(syst) at 0.9 TeV and R_{|y|<0.5}=0.991±0.005(stat)±0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions.

Sphingosine-1-phosphate Signaling in Human Submandibular Cells

Sphingosine-1-phosphate (S1P) is a significant lipid messenger modulating many physiological responses. S1P plays a critical role in autoimmune disease and is suggested to be involved in Sjögren’s syndrome pathology. However, the mechanism of S1P signaling in salivary glands is unclear. Here we studied the effects of S1P on normal human submandibular gland cells. S1P increased levels of the intracellular Ca2+ concentration ([Ca2+]i), which was inhibited by pre-treatment with U73122 or 2-aminoethoxydiphenyl borate (2-APB). Pre-treated S1P did not inhibit subsequent carbachol-induced [Ca2+]i increase, which suggests that S1P and muscarinic signaling are independent of each other. S1P1, S1P2, and S1P3 receptors SphK1 and SphK2 were commonly expressed in human salivary gland cells. S1P, but not carbachol, induces the expression of interleukin-6 and Fas. Our results suggest that S1P triggers Ca2+ signaling and the apoptotic pathway in normal submandibular gland cells, which suggests in turn that S1P affects the progression of Sjögren’s syndrome.

Superconductivity in CuxBi2Se3 and its implications for pairing in the undoped topological insulator

Bi2Se3 is one of a handful of known topological insulators. Here we show that copper intercalation in the van der Waals gaps between the Bi2Se3 layers, yielding an electron concentration of approximately 2x10{20} cm{-3}, results in superconductivity at 3.8 K in CuxBi2Se3 for 0.12<or=x<or=0.15. This demonstrates that Cooper pairing is possible in Bi2Se3 at accessible temperatures, with implications for studying the physics of topological insulators and potential devices.

Triple Negative Breast Cancer Has a Worse Prognosis within 3 Years after Treatment Compared to Non-Triple Negative Breast Cancer

BackgroundTriple negative breast cancers (TNBC) become known as poor prognosis generally. Our purpose was to compare the clinical features and outcomes for TNBC with other subtypes of breast cancers in Korea.MethodsWe included 2,907 patients who diagnosed breast cancer and treated at Asan Medical Center from 2003 to 2005. Clinical and pathologic parameters, disease-free survival (DFS) and overall survival (OS) were compared between patients with TNBC and non-TNBC. All features were reviewed throughout medical records retrospectively.Results622 patients (21.4%) had TNBC. TNBC patients was associated with younger age, larger size, positive nodal involvement, overweight, family history, elevation of CaAg15-3, high tumor grade, positive p53 compared non-TNBC. The patients were followed for a median of 54 months (range 1-76 months). Relapse-free survival was 86.3% and 92.6% for TNBC and non-TNBC, respectively, with significant difference (P&lt;0.0001). Overall survival was also 88.9% and 96.1% for TNBC and non-TNBC (P&lt;0.0001). Compared with non-TNBC patients, TNBC had an increased likelihood of recurrence and death within 3 years after diagnosis but not thereafter. In non-TNBC, the recurrence risk and death risk seemed to be relatively constant. In univariate analysis for worse prognostic factors of TNBC associated with DFS and OS revealed that statistically significant in large tumor size, nodal status, CA15-3, Lymphovascular invasion. In multivariate analysis, nodal status was a prognostic factor for DFS (P=0.06, HR=2.28; 95% CI, 0.92-3.04) and OS (P&lt;0.0001, HR=5.22; 95% CI, 2.11-12.96) of TNBC. Lymphovascular invasion was only poor prognostic factor for DFS (P=0.026, HR=10.2, 95% CI, 1.31-76.8), not for OS.ConclusionsTNBC has a worse prognosis than non-TNBC patients, but this effect is limited within 3 years after diagnosis. The most competent prognostic factor of recurrence and death for TNBC is a nodal status. We plan that perform analysis for prognosis according to hormone receptor and HER-2 receptor status sooner.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4044.

Can We Skip Sentinel Lymph Node Biopsy in Patients Who Have Microinvasive Breast Cancer?

Background: Sentinel lymph node(SLN) biopsy in patients with ductal carcinoma in situ(DCIS) was controversial. We may skip SLN biopsy when we performed conserving operation with small sized DCIS. But sometimes we can find DCIS with micro-invasive breast cancer (MIC) after operation. Should another operation be performed? We determined the incidence of positive axillary lymph node (ALNs) in patients with MIC, and the predictive factors of ALNs metastasis in these patients. Methods: Between July 1989 and January 2008, 9046 patients had operations performed on invasive breast cancers at Asan Medical Center. From July1989 to February 2003, ALND was performed to surgically stage the axilla. Since May 2003, SNB has been routinely performed for all cases. Patients who were treated with neoadjuvant chemotherapy and those who had no identifiable ALNs at surgery were excluded from the study. We retrospectively checked clinical and pathologic variables including diagnosis, patient demographics, size of DCIS, grade, multi-focal lesion, hormone receptor status, lymphatic invasion status etc. Results: 265 patients were identified with microinvasive (pathologic stage T1mic) breast cancer. Among these patients, 12 patients didn't have ALN study. 2 patients had bilateral MIC. The research was conducted on the remaining 255 cases. There were 13 cases of ALN metastases identified in this group of patients(5%). Young age (p=0.006), multifocal lesion (p=0.040) and lymphatic invasion (p&lt;0.0001) were predictive factors for ALN metastases. There was no incidence of metastatic ALNs among the old age (≥50) patients of this group. Conclusion: As the incidence of ALN metastases in MIC patients is very small, particularly in those who had no lymphatic invasion, single lesion and among old age patients. So we think conservative treatment is one of the available options for these patients. However, due to the size of the subject group in this study, it needs to be validated through extensive prospective research.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1019.

Prognostic significance of serum vascular endothelial growth factor per platelet count in gastric cancer patients

e22031

Background: Recent studies have shown that VEGF expression not in tissues but in serum sample is correlated with tumor vascularity, and high serum VEGF levels could predict poor prognosis in cancer patients. However there are limited data regarding the clinical and prognostic significance of serum VEGF levels per platelet count in advanced gastric cancer. In this study, we conducted a study to evaluate the prognostic implication of serum VEGF per platelet count in patients with advanced gastric cancer. Methods: 111 patients with histologically confirmed gastric cancer, 10 patients with early gastric cancer were included and control serum samples were acquired from 10 healthy volunteers. The levels of VEGF were measured using human VEGF quantitative enzyme-linked immunosorbent assay (ELISA). Survival curves were calculated using the Kaplan-Meier method and survival comparisons were made by the log rank test in metastatic gastric cancer. The Cox proportional hazards regression model was utilized for multivariate analyses after univariate analysis defined relevant prognostic variables. Results: A trend toward a significant positive correlation between serum VEGF and platelet counts was observed in patients of AGC (r = 0.477, P = 0.000) and there was a significant correlation between serum VEGF levels and differentiation of tumor (p = 0.014), stage (p = 0.036). The overall survival (log rank, p =0.0432) and the progression free survival (median 4.5 vs. 8.9 months; log rank, p =0.0116) were significantly shorter in patients with high VEGF per platelet count (≥1.626 pg/106). In the multivarivate analysis, performance status (P=0.025), the presence of peritoneal carcinomatosis (P=0.006), serum VEGF per platelet (P=0.005) were found to be significantly associated with poor progression free survival. Conclusions: This study demonstrated that serum VEGF per platelet count are correlated with poor overall survival and progression free survival in patients with advanced gastric cancer. Therefore measurement of serum VEGF per platelet might be useful markers for predicting disease progression and prognosis of advanced gastric cancer.

No significant financial relationships to disclose.

Increased expression of p63 and survivin in cholesteatomas

CONCLUSION

This study showed increased expression of p63 and survivin in cholesteatoma. Our finding indicates a putative role of p63 and survivin in the development of certain cholesteatomas.

OBJECTIVES

Keratinocytes in cholesteatoma demonstrate uncoordinated hyperproliferation, migration, and invasion properties. p63 is a p53 homologue and a marker expressed in replicating keratinocytes. Survivin is an inhibitor of apoptosis protein that is abundantly expressed in most solid and hematologic malignancies. The purpose of this study was to investigate the differential expression of p63 and survivin in human middle ear cholesteatoma epithelium.

MATERIALS AND METHODS

The expression levels of p63 and survivin protein were examined by immunohistochemical analysis of 40 cholesteatomas and 5 skin tissues obtained from patients during ear surgery.

RESULTS

Expression of p63 protein was diffusely observed in entire samples of cholesteatoma, especially in acquired cholesteatoma, compared with the control group. Congenital cholesteatoma showed variable p63 reactivity in a basal cell-like pattern. Primary and recurrent cholesteatomas showed no significant difference in p63 expression. Survivin was detected in 31 of 40 cholesteatoma samples. Acquired cholesteatomas showed especially increased survivin expression compared with congenital cases. The expression of p63 was correlated with survivin expression.

The role of FDG-PET for preoperative evaluation of regional lymph node metastases in locally advanced breast cancer

Abstract #4021

Backgound: The aim of this study was to evaluate the role of FDG-PET in detecting regional lymph node metastases in locally advanced breast cancer.&#x2028; Methods: FDG-PET was performed in 114 women with locally advanced breast cancer. Among them, 7 were with primary tumor larger than 5cm, 18 were with inflammatory breast cancer, and 89 were with clinically palpable axillary lymph node metastases. FDG uptakes of axillary, internal mammary, and supraclavicular lymph node were correlated by comparing pathologic and radiographic findings.&#x2028; Results: The sensitivity, specificity, and positive predictive value of FDG-PET for detection of axillary lymph node metastases in 83 patients who did not receive neoadjuvant chemotherapy were 91%, 33.3 % and 94.7% respectively. Among the 83 patients, 4 were with false-negative and 6 were with false-positive. Those for detection of axillary lymph node metastases in 12 patients who received neoadjuvant chemotherapy were 55.6%, 100%, and 100% respectively, and 4 of them were with false-negative and no one was with false-positive results. The sensitivity and positive predictive value of combined assessment of clinical examination and ultrasound scan on axillary node metastases were 92.1% and 93.3% in 81 patients. Those of combined assessment of clinical examination, ultrasound scan, and PET were 100% and 95.7% in 69 patients. FDG uptake in internal mammary node was seen in 14 out of 114 patients (12.2%). The positive predictive value of FDG-PET for detection of internal mammary metastases in 9 patients with pathologic confirmation was 75%. 6 of them were with true-positive, 2 were with false-positive, and 1 was false-negative. Among the 6 true positive patients, 3 were not detected internal mammary metastases in ultrasound scan. FDG uptake in the supraclavicular node was seen in 22 out of 114 patients (19.2%). The positive predictive value of FDG-PET for detection of supraclavicular metastases in 12 patients with pathologic confirmation was 58.3%. 7 of them were with true –positive and 5 were with false-positive. 1 of 7 true-positive patients was not detected supraclavicular lymph node metastases in ultrasound scan.&#x2028; Conclusions: The sensitivity of FDG-PET for detection of axillary lymph node metastases was higher than that of FDG-PET for detection of internal mammary or supraclavicular lymph node. The addition of FDG-PET to standard work-up of locally advanced breast cancer patients could provide a more precise evaluation of regional lymph node metastases. Positive combined assessment of clinical examination, ultrasound scan and PET on axillary node metastases also could be an indication for full ALND without SNB.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4021.