Ferromagnetism and Charge Order from a Frozen Electron Configuration in Strained Epitaxial LaCoO_{3}

We report ordering of the cobalt electron configuration in ferromagnetic strained epitaxial LaCoO_{3}. Specifically, the presence of charge order is demonstrated from distinct features of the resonant cobalt contribution to superstructure reflections. Density functional theory calculations show that the observed order is consistent with the spin-state periodicity predicted to give rise to ferromagnetism in LaCoO_{3}. Through the modification of symmetry by strain, concurrent frozen charge and spin-state order are stabilized, giving rise to long-range magnetic order.

Predictors of failure to detect early hepatocellular carcinoma in patients with chronic hepatitis B who received regular surveillance

BACKGROUND

A proportion of chronic hepatitis B (CHB) patients are diagnosed with advanced hepatocellular carcinoma (HCC) despite regular surveillance.

AIMS

To determine predictors for HCC detection failure in CHB patients who underwent regular surveillance.

METHODS

CHB patients with well-preserved liver function, who underwent ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, were enrolled. Cox regression analysis was used to identify predictors for detection failure, defined as HCC initially diagnosed at Barcelona Clinic Liver Cancer (BCLC) stage B or C.

RESULTS

Of the 4590 CHB patients (mean age, 52.1 years; men, 61.6%), 169 patients were diagnosed with HCC (3.68%) and 35 (20.7%) HCC patients were initially diagnosed with HCC BCLC stage B or C. The cumulative incidence of HCC detection failure was 0.2% at year 1 and 1.3% at year 5. Multivariate analyses indicated that cirrhosis (hazard ratio [HR], 3.078; 95% CI, 1.389-6.821; P = 0.006), AFP levels ≥9 ng/mL (HR, 5.235; 95% CI, 2.307-11.957; P = 0.010), and diabetes mellitus (HR, 3.336; 95% CI, 1.341-8.296; P = 0.010) were independent predictors of HCC detection failure. Another model that incorporated liver stiffness (LS) values identified LS values ≥11.7 kPa (HR, 11.045; 95% CI, 2.066-59.037; P = 0.005) and AFP levels ≥9 ng/mL (HR, 4.802; 95% CI, 1.613-14.297; P = 0.005) as predictors of detection failure.

CONCLUSIONS

In CHB patients undergoing regular surveillance with ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, the HCC detection failure rate was not high (0.8% per person; 0.1% per test). However, careful attention should be paid in patients with advanced liver fibrosis (clinical cirrhosis or LS value >11.7 kPa), high AFP levels, or diabetes mellitus, who are prone to surveillance failure.

Abstract P2-02-18: Higher mutation burden and mutant allele fraction of circulating tumor DNA corresponds to worse progression free survival in metastatic breast cancer patients

Introduction: Genomic profiling of circulating tumor DNA (ctDNA) allows non-invasive monitoring of tumor genetic changes and molecular heterogeneity. In addition to actionable mutations, mutational landscape derived from ctDNA could provide a better representation of overall tumor burden and tumor heterogeneity, as well as potentially impact clinical outcomes. To evaluate this hypothesis, this study assessed the association of mutation burden and average mutant allele fraction (MAF) with tumor subtype, therapeutic response, and survival in patients with metastatic breast cancer.

Methods: Whole blood samples from patients with metastatic breast cancer were collected during clinic visits before start of a new therapy. Plasma-derived cell-free DNA underwent complete next-generation sequencing of 73 cancer-related genes with the Guardant360 test. Mutation burden was defined as the number of genes with mutations, and average MAF was calculated as the sum of the highest MAF for each mutated gene divided by the number of genes with mutations. Time to progression was measured from the date of new treatment initiation after circulating tumor DNA collection to the date of progression. Multivariate cox proportional hazard models assessed the association of mutation burden and average MAF with progression free survival (PFS), adjusted for age, receptor subtype (hormone receptor positive, HR+; human epidermal growth factor 2 positive, HER2+; triple negative breast cancer, TNBC), treatment subtype (chemotherapy vs. targeted therapy), and number of prior metastatic breast cancer therapies. A p value of 0.05 was considered statistically significant.

Results: The study population consisted of 158 women with metastatic breast cancer (108 HR+, 14 HER2+, 19 TNBC) with a median age of 59 years and a median of 2 prior metastatic breast cancer therapies. Median follow up time was 4.0 months, and median PFS was 15.7 months. Mutation burden was greater in triple negative compared to hormone receptor positive breast cancer (7.5 vs. 4.8, p = 0.02) but no different in patients with > 2 prior metastatic therapies vs. not (5.1 vs. 4.7, p = 0.60) and age >45 vs. not (5.0 vs. 3.9; p = 0.26). In univariate models, high mutation burden (> median of 2) and high MAF (> median of 1.4) were significantly associated with worse PFS (Table). These results were similar in effect size and significance when adjusted for age, receptor subtype, treatment subtype, and number of prior metastatic breast cancer therapies. Impact of mutation burden on response to specific therapies will be presented at the meeting.

VariableHazard Ratio95% Confidence Intervalp valueHigh mutation burden1.991.12-3.540.02High mutant allele fraction1.881.06-3.330.03

Conclusions: Higher ctDNA mutation burden and average MAF is associated with worse progression free survival and possibly reflects a more treatment refractory phenotype. Whether immunotherapy, alone or in combination, could influence the clinical outcomes in metastatic breast cancer patients with high ctDNA mutation burden is unclear and warrants additional research.

Citation Format: Keenan T, Juric D, Niemierko A, Spring L, Park H, Malvarosa G, Beeler M, Moy B, Ellisen L, Isakoff S, Bardia A. Higher mutation burden and mutant allele fraction of circulating tumor DNA corresponds to worse progression free survival in metastatic breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-02-18.

Abstract PD1-13: Somatic BRCA mutation detection by circulating tumor DNA analysis in patients with metastatic breast cancer: Incidence and association with tumor genotyping results, germline BRCA mutation status, and clinical outcomes

Introduction:

BRCA mutations may impact patient outcomes, as well as chemotherapy response in patients with breast cancer (BC). While germline BRCA mutations have been well-studied, the incidence and clinical impact of somatic BRCA mutations have not been well-described. We evaluated the presence of BRCA mutations, and the association between somatic BRCA mutations with clinical outcomes in patients with metastatic breast cancer (MBC).

Methods:

We identified patients with MBC who underwent ctDNA testing by Guardant360 at our institution before the start of a new therapy. From this subset of patients, we subsequently identified those patients with circulating tumor DNA (ctDNA) BRCA 1 or 2 mutations. We conducted a retrospective review of medical and pathology records to identify tumor subtype, germline BRCA testing results, and tissue genotyping results based on institutional Snapshot-NGS genotyping assay. In addition, we conducted a multivariate analysis to evaluate the hazard ratio (HR) for the association between ctDNA BRCA mutation and progression free survival (PFS) adjusting for age, number of prior therapies, and type of therapy.

Results

Among patients with MBC (N = 178), 27 (15.2%) had BRCA alterations detected by ctDNA analysis. Among patients with ctDNA BRCA alterations, the median age at metastatic diagnosis was 53; 16/24 (66.6%) had hormone receptor (HR)+/HER2- BC, 5/24 (20.8%) had triple negative (TN) BC, 2/24 (8.3%) had HR-/HER2+ BC, and 1/24 (4.2%) had HR+/HER2+ BC. Of patients with ctDNA BRCA mutations, only a minority (16.7%) had BRCA alterations detected by genotyping of archival tumor, and only 1 (3.7%) had a germline BRCA mutation (BRCA 1). In multivariate analysis, patients with BRCA mutant tumors, had similar median PFS as compared to non-BRCA mutant breast cancer (HR: 1.17; p = 0.58). Overall survival analysis and impact of BRCA mutations on response to therapy, particularly DNA damaging agents, will be presented at the meeting.

Conclusions:

BRCA mutations by ctDNA are detectable in a significant proportion of MBC patients. Most BRCA mutations detected by ctDNA were not identified by genotyping of archival tissue, and were not associated with germline BRCA mutations, suggesting that somatic BRCA mutations may be detected by sensitive blood-based genotyping assays in patients who are not known BRCA carriers. The therapeutic impact of DNA damaging agents and PARP inhibitors in MBC patients with somatic BRCA alterations is not known and warrants additional research.

Citation Format: Vidula N, Isakoff SJ, Niemierko A, Malvarosa G, Park H, Abraham E, Spring L, Peppercorn J, Moy B, Ellisen LW, Juric D, Bardia A. Somatic BRCA mutation detection by circulating tumor DNA analysis in patients with metastatic breast cancer: Incidence and association with tumor genotyping results, germline BRCA mutation status, and clinical outcomes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD1-13.

Abstract P5-20-02: HER2 mutations detected by ctDNA in ER+/HER2- metastatic breast cancer patients: Incidence and impact on clinical outcomes

Background: While the human epidermal growth factor receptor 2 (HER2) gene has long been linked with the pathogenesis and prognosis of breast cancer, its significance has been recognized only when the receptor has been amplified. However, rare, but actionable, somatic mutations in HER2, without HER2 gene amplification, have been described in breast cancer based on molecular analysis of metastatic specimens (frequency ˜ 1%). Little is known about the incidence based on blood-based genotyping assays, as well as impact of HER2 mutations on clinical outcomes in patients with ER+/HER2- metastatic breast cancer (MBC).

Methods: We evaluated the presence of HER2 mutations based on routine tissue and blood-based genotyping assays, ordered by treating oncologists at our institution, for patients with estrogen receptor positive (ER+)/HER2 negative MBC. The tissue analysis was based on SNAPSHOT-NGS, an anchored multiplex polymerase chain reaction assay that detects single nucleotide variants (SNV) and insertions/deletions (indel), and the blood-based genotyping analysis was based on circulating tumor DNA (ctDNA) detection using the Guardant 360 panel, a next-generation sequencing (NGS) assay capable of detecting mutations with comparable sensitivity to SNAPSHOT. Patients with acquired HER2 mutations were identified, and multivariate analysis was performed to evaluate the hazard ratio (HR) for the association between HER2 mutations and progression free survival (PFS), adjusting for age and number of prior therapies.

Results: Among the ER+/HER2- MBC patients (N=118), 11% (N= 13) were found to have acquired HER2 mutation by ctDNA analysis, but no HER2 mutations were identified in any of patients based on tissue-based molecular analysis of archival specimens. Among patients with HER2 mutant, ER+/HER2- MBC, the median age at metastatic diagnosis was 57.34 (range 51.5-67.1) years, 7.7% had de-novo metastatic disease, and 30.8% had prior CDK 4/6 inhibitor therapy. In terms of outcomes, in the multivariate model, patients with HER2 mutant breast cancer had similar PFS when treated with endocrine and targeted therapy combination (HR = 0.24; p = 0.21), and trended towards worse PFS with chemotherapy (HR = 2.69; p = 0.06), as compared to non-HER2 mutant group, albeit duration of follow up was limited (median duration = 6.7 months). Of note, most of the detected HER2 mutations were activating or deleterious, but not all were clonal. Updated outcome data, including overall survival, will be presented at the meeting.

Conclusions: A much larger subset of patients with ER+/HER2- MBC have HER2 mutations detectable by ctDNA, but not by tissue, which highlights the need for blood-based biomarker monitoring for identification of actionable mutations, as well as the potential clinical utility in development of genotype driven trials for patients with HER2 mutant, ER+/HER2- MBC.

Citation Format: Medford A, Juric D, Niemierko A, Malvarosa G, Park H, Shellock M, Spring L, Moy B, Isakoff S, Ellisen L, Bardia A. HER2 mutations detected by ctDNA in ER+/HER2- metastatic breast cancer patients: Incidence and impact on clinical outcomes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-20-02.

Evolving affinity between Coulombic reversibility and hysteretic phase transformations in nano-structured silicon-based lithium-ion batteries

Nano-structured silicon is an attractive alternative anode material to conventional graphite in lithium-ion batteries. However, the anode designs with higher silicon concentrations remain to be commercialized despite recent remarkable progress. One of the most critical issues is the fundamental understanding of the lithium-silicon Coulombic efficiency. Particularly, this is the key to resolve subtle yet accumulatively significant alterations of Coulombic efficiency by various paths of lithium-silicon processes over cycles. Here, we provide quantitative and qualitative insight into how the irreversible behaviors are altered by the processes under amorphous volume changes and hysteretic amorphous-crystalline phase transformations. Repeated latter transformations over cycles, typically featured as a degradation factor, can govern the reversibility behaviors, improving the irreversibility and eventually minimizing cumulative irreversible lithium consumption. This is clearly different from repeated amorphous volume changes with different lithiation depths. The mechanism behind the correlations is elucidated by electrochemical and structural probing.

Simultaneous Subtotal Pancreatectomy and Streptozotocin Injection for Diabetes Modeling in Cynomolgus Monkeys

BACKGROUND

In an experimental animal model of islet transplantation, stable induction of insulin-dependent diabetes mellitus (IDDM) and islet isolation from donor pancreas are essential. Total pancreatectomy for IDDM induction and islet procurement in nonhuman primates leads to unwanted loss of exocrine function and may lead to morbidities associated with IDDM.

METHODS

IDDM induction with streptozotocin (STZ) is associated with drug toxicity of STZ and necessitates the killing of another animal for islet procurement. In this study, we performed a subtotal pancreatectomy combined with reduced STZ injection to induce IDDM and procure islets in a nonhuman primate model.

RESULTS

Twelve cynomolgus monkeys received low-dose STZ injections (60 mg/kg) simultaneously with subtotal pancreatectomy. All monkeys recovered from the procedure without complications. IDDM was induced in the animals. 57,691 ± 16,050 islets were isolated from the resected pancreas and transplanted into other monkeys.

CONCLUSIONS

Simultaneous subtotal pancreatectomy and low-dose STZ injection represent an effective and safe method to create an animal model of insulin dependence diabetes, while at the same time providing sufficient amounts of fresh islet cells for allotransplantation without requiring killing of additional animals.

Evidence for Isospin Violation and Measurement of CP Asymmetries in B→K^{*}(892)γ

We report the first evidence for isospin violation in B→K^{*}γ and the first measurement of the difference of CP asymmetries between B^{+}→K^{*+}γ and B^{0}→K^{*0}γ. This analysis is based on the data sample containing 772×10^{6}BB[over ¯] pairs that was collected with the Belle detector at the KEKB energy-asymmetric e^{+}e^{-} collider. We find evidence for the isospin violation with a significance of 3.1σ, Δ_{0+}=[+6.2±1.5(stat)±0.6(syst)±1.2(f_{+-}/f_{00})]%, where the third uncertainty is due to the uncertainty on the fraction of B^{+}B^{-} to B^{0}B[over ¯]^{0} production in ϒ(4S) decays. The measured value is consistent with predictions of the standard model. The result for the difference of CP asymmetries is ΔA_{CP}=[+2.4±2.8(stat)±0.5(syst)]%, consistent with zero. The measured branching fractions and CP asymmetries for charged and neutral B meson decays are the most precise to date. We also calculate the ratio of branching fractions of B^{0}→K^{*0}γ to B_{s}^{0}→ϕγ.

Search for CP Violation and Measurement of the Branching Fraction in the Decay D^{0}→K_{S}^{0}K_{S}^{0}

We report a study of the decay D^{0}→K_{S}^{0}K_{S}^{0} using 921  fb^{-1} of data collected at or near the ϒ(4S) and ϒ(5S) resonances with the Belle detector at the KEKB asymmetric energy e^{+}e^{-} collider. The measured time-integrated CP asymmetry is A_{CP}(D^{0}→K_{S}^{0}K_{S}^{0})=(-0.02±1.53±0.02±0.17)%, and the branching fraction is B(D^{0}→K_{S}^{0}K_{S}^{0})=(1.321±0.023±0.036±0.044)×10^{-4}, where the first uncertainty is statistical, the second is systematic, and the third is due to the normalization mode (D^{0}→K_{S}^{0}π^{0}). These results are significantly more precise than previous measurements available for this mode. The A_{CP} measurement is consistent with the standard model expectation.

YH12852, a potent and highly selective 5-HT4 receptor agonist, significantly improves both upper and lower gastrointestinal motility in a guinea pig model of postoperative ileus

BACKGROUND

Postoperative ileus (POI) is a transient gastrointestinal (GI) dysmotility that commonly develops after abdominal surgery. YH12852, a novel, potent and highly selective 5-hydroxytryptamine 4 (5-HT₄ ) receptor agonist, has been shown to improve both upper and lower GI motility in various animal studies and may have applications for the treatment of POI. Here, we investigated the effects and mechanism of action of YH12852 in a guinea pig model of POI to explore its therapeutic potential.

METHODS

The guinea pig model of POI was created by laparotomy, evisceration, and gentle manipulation of the cecum for 60 seconds, followed by closure with sutures under anesthesia. Group 1 received an oral administration of vehicle or YH12852 (1, 3, 10 or 30 mg/kg) only, while POI Group 2 was intraperitoneally pretreated with vehicle or 5-HT₄ receptor antagonist GR113808 (10 mg/kg) prior to oral dosing of vehicle or YH12852 (3 or 10 mg/kg). Upper GI transit was evaluated by assessing the migration of a charcoal mixture in the small intestine, while lower GI transit was assessed via measurement of fecal pellet output (FPO).

KEY RESULTS

YH12852 significantly accelerated upper and lower GI transit at the doses of 3, 10, and 30 mg/kg and reached its maximal effect at 10 mg/kg. These effects were significantly blocked by pretreatment of GR113808 10 mg/kg.

CONCLUSION AND INFERENCES

Oral administration of YH12852 significantly accelerates and restores delayed upper and lower GI transit in a guinea pig model of POI. This drug may serve as a useful candidate for the treatment of postoperative ileus.

The effects and mechanism of action of methane on ileal motor function

BACKGROUND

Methane has been associated with constipation-predominant irritable bowel syndrome, slowing intestinal transit time by augmenting contractile activity. However, the precise mechanism underlying this effect remains unclear. Therefore, we investigated the mechanisms underlying the effect of methane on contractile activity, and whether such effects are mediated by nerve impulses or muscular contraction.

METHODS

We connected guinea pig ileal muscle strips to a force/tension transducer and measured amplitudes of contraction in response to electrical field stimulation (EFS; 1, 2, 8, 16 Hz) following methane infusion in the presence of tetradotoxin (TTX), atropine, guanethidine, or GR 113808. We then performed calcium imaging using Oregon Green 488 BAPTA-1 AM in order to visualize changes in calcium fluorescence in response to EFS following methane infusion in the presence of TTX, atropine, or a high K⁺ solution.

KEY RESULTS

Methane significantly increased amplitudes of contraction (P<.05), while treatment with TTX abolished such contraction. Methane-induced increases in amplitude were inhibited when lower-frequency (1, 2 Hz) EFS was applied following atropine infusion (P<.05). Neither guanethidine nor GR 113808 significantly altered contraction amplitudes. Methane significantly increased calcium fluorescence, while this increase was attenuated following atropine infusion (P<.05). Although calcium fluorescence was increased by the high K⁺ solution under pretreatment with TTX, the intensity of fluorescence remained unchanged after methane infusion.

CONCLUSIONS AND INFERENCES

The actions of methane on the intestine are influenced by the cholinergic pathway of the enteric nervous system. Our findings support the classification of methane as a gasotransmitter.

aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay

We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. Details of the method, apparatus, detectors, data acquisition, and data reduction scheme are presented, along with a discussion of the important systematic effects.

Measurement of the Electron-Antineutrino Angular Correlation in Neutron β Decay

We report the first result for the electron-antineutrino angular correlation (a coefficient) in free neutron β decay from the aCORN experiment. aCORN uses a novel method in which the a coefficient is proportional to an asymmetry in proton time of flight for events where the β electron and recoil proton are detected in delayed coincidence. Data are presented from a 15 month run at the NIST Center for Neutron Research. We obtained a=-0.1090±0.0030(stat)±0.0028(sys), the most precise measurement of the neutron a coefficient reported to date.

Robotic colorectal surgery: previous laparoscopic colorectal experience is not essential

A background in minimally invasive colorectal surgery (MICS) has been thought to be essential prior to robotic-assisted colorectal surgery (RACS). Our aim was to determine whether MICS is essential prior to starting RACS training based on results from our initial experience with RACS. Two surgeons from our centre received robotic training through the European Academy of Robotic Colorectal Surgery (EARCS). One surgeon had no prior formal MICS training. We reviewed the first 30 consecutive robotic colorectal procedures from a prospectively maintained database between November 2014 and January 2016 at our institution. Fourteen patients were male. Median age was 64.5 years (range 36-82) and BMI was 27.5 (range 20-32.5). Twelve procedures (40%) were performed by the non-MICS-trained surgeon: ten high anterior resections (one conversion), one low anterior resection and one abdomino-perineal resection of rectum (APER). The MICS-trained surgeon performed nine high and four low anterior resections, one APER and in addition three right hemicolectomies and one abdominal suture rectopexy. There were no intra-operative complications and two patients required re-operation. Median post-operative stay was five days (range 1-26). There were two 30-day re-admissions. All oncological resections had clear margins and median node harvest was 18 (range 9-39). Our case series demonstrates that a background in MICS is not essential prior to starting RACS training. Not having prior MICS training should not discourage surgeons from considering applying for a robotic training programme. Safe and successful robotic colorectal services can be established after completing a formal structured robotic training programme.