Probing ultrafast spin-relaxation and precession dynamics in a cuprate Mott insulator with seven-femtosecond optical pulses

A charge excitation in a two-dimensional Mott insulator is strongly coupled with the surrounding spins, which is observed as magnetic-polaron formations of doped carriers and a magnon sideband in the Mott-gap transition spectrum. However, the dynamics related to the spin sector are difficult to measure. Here, we show that pump-probe reflection spectroscopy with seven-femtosecond laser pulses can detect the optically induced spin dynamics in Nd2CuO4, a typical cuprate Mott insulator. The bleaching signal at the Mott-gap transition is enhanced at ~18 fs. This time constant is attributable to the spin-relaxation time during magnetic-polaron formation, which is characterized by the exchange interaction. More importantly, ultrafast coherent oscillations appear in the time evolution of the reflectivity changes, and their frequencies (1400-2700 cm-1) are equal to the probe energy measured from the Mott-gap transition peak. These oscillations can be interpreted as the interference between charge excitations with two magnons originating from charge-spin coupling.

Rare variants in RNF213, a susceptibility gene for moyamoya disease, are found in patients with pulmonary hypertension and aggravate hypoxia-induced pulmonary hypertension in mice

Ring finger 213 (RNF213) is a susceptibility gene for moyamoya disease (MMD), a progressive cerebrovascular disease. Recent studies suggest that RNF213 plays an important role not only in MMD, but also in extracranial vascular diseases, such as pulmonary hypertension (PH). In this study, we undertook genetic screening of RNF213 in patients with PH and performed functional analysis of an RNF213 variant using mouse models. Direct sequencing of the exons in the C-terminal region of RNF213, where MMD-associated mutations are highly clustered, and of the entire coding exons of BMPR2 and CAV1, the causative genes for PH, was performed in 27 Japanese patients with PH. Two MMD-associated rare variants (p.R4810K and p.A4399T) in RNF213 were identified in two patients, three BMPR2 mutations (p.Q92H, p.L198Rfs*4, and p.S930X) were found in three patients, whereas no CAV1 mutations were identified. To test the effect of the RNF213 variants on PH, vascular endothelial cell (EC)-specific Rnf213 mutant transgenic mice were exposed to hypoxia. Overexpression of the EC-specific Rnf213 mutant, but neither Rnf213 ablation nor EC-specific wild-type Rnf213 overexpression, aggravated the hypoxia-induced PH phenotype (high right ventricular pressure, right ventricular hypertrophy, and muscularization of pulmonary vessels). Under hypoxia, electron microscopy showed unique EC detachment in pulmonary vessels, and western blots demonstrated a significant reduction in caveolin-1 (encoded by CAV1), a key molecule involved in EC functions, in lungs of EC-specific Rnf213 mutant transgenic mice, suggestive of EC dysfunction. RNF213 appears to be a genetic risk factor for PH and could play a role in systemic vasculopathy.

Shorter duration of antibiotic treatment for acute bacteraemic cholangitis with successful biliary drainage: a retrospective cohort study

OBJECTIVES

To assess the effectiveness of short duration antimicrobial therapy for acute cholangitis with bacteraemia.

METHODS

We conducted a retrospective cohort study of patients with acute bacteraemic cholangitis with successful biliary duct drainage at a single centre in Japan. We compared short-course antimicrobial therapy (SCT, ≤7 days) and long-course therapy (LCT, ≥8 days), with a primary outcome of 30-day mortality. We constructed logistic regression models for mortality and a composite outcome, including mortality, recurrence, recrudescence, new bacteraemia, liver abscess or other complications related to cholangitis. We also developed a propensity score for SCT with inverse probability weighting for both the primary outcome and the composite outcome.

RESULTS

We identified 263 patients in our cohort; 86 (32.7%) patients received SCT and the remaining 177 (67.3%) received LCT. The median durations of SCT and LCT were 6 days (range 2-7 days) and 12 days (range 8-46 days), respectively. The 30-day mortalities of SCT and LCT were 4.7% (4/85) and 5.7% (10/176), respectively (p 1.00). Logistic regression analysis showed that the odds ratio of SCT for 30-day mortality and the composite outcome were 1.07 (95% CI 0.25-4.52, p 0.93) and 1.08 (95% CI 0.48-2.45, p 0.85), respectively. Propensity score analyses for both 30-day mortality and the composite outcome did not demonstrate a difference between SCT and LCT (p 0.65 and p 0.95, respectively).

CONCLUSIONS

SCT with a median duration of 6 days did not have worse outcomes than LCT with a median duration of 12 days. Shortening the duration of antimicrobial therapy may be a reasonable option when treating acute bacteraemic cholangitis following successful biliary drainage.

Abstract P3-13-06: Tailored neoadjuvant endocrine and chemo-endocrine therapy for postmenopausal patients with estrogen receptor-positive human epidermal growth factor receptor 2-negative primary breast cancer

Aims We investigated the efficacy and safety of initial neoadjuvant endocrine therapy with exemestane (EXE) alone followed by subsequent tailored treatment with EXE alone for responders or EXE plus oral metronomic cyclophosphamide (CPA) for non-responders.

Methods In this multicenter open-label phase II study, we enrolled postmenopausal patients with primary invasive estrogen receptor (ER)-positive, HER2-negative, stage I–IIIA (T1c–T3 N0–2 M0) breast cancer and Ki67 index ≤ 30%. Patients first received EXE 25mg/day for 12 weeks. Based on clinical response and change in Ki67 index in response to the initial therapy, patients who achieved complete response (CR), partial response (PR) with Ki67 index ≤5% after treatment, or stable disease (SD) with Ki67 index ≤5% both before and after treatment were defined as responders. Non-responders were defined as patients with PR and Ki67 index >5% after treatment, or SD and Ki67 index >5% before or after treatment. For the subsequent 24 weeks, responders continued the EXE monotherapy (continued EXE group), whereas non-responders switched to combination therapy with EXE plus CPA 50mg/day (EXE+CPA group). The primary endpoint was clinical response (CR and PR) at weeks 24 and 36.

Results A total of 59 patients (median age 69 years, range 53–86 years) were enrolled between January 2011 and July 2015. After exclusion of 3 (2 with progressive disease, 1 with an adverse event, AE) who discontinued treatment in the initial 12-week EXE monotherapy period, 56 remained enrolled to receive subsequent treatment. After 8–12 weeks of the initial EXE monotherapy, 14 patients were classified as responders (9 with PR and Ki67 index ≤5% after treatment; 5 with SD and Ki67 index ≤5% before and after treatment), whereas 42 were classified as non-responders (3 with PR and Ki67 index >5% after treatment; 39 with SD and Ki67 index >5% before or after treatment). Clinical response rates at weeks 24 and 36 were 85% (12/14, 95%CI 57.2–98.2%) and 76% (10/13, 95%CI 46.2–95.0%), respectively, in the continued EXE group, and 56% (23/41, 95%CI 39.7–71.5%) and 76% (30/39, 95%CI 60.7–88.9%), respectively, in the EXE+CPA group. At week 36, no significant difference was found in median Ki67 index between the continued EXE and EXE+CPA groups (3.5% and 4.0%, respectively). The proportion of patients with preoperative endocrine prognostic index (PEPI) 0 was also similar between the continued EXE and EXE+CPA groups (21.4% and 23.8%, respectively). The breast-conserving surgery rate was 71.4% and 69.0%, respectively. Grade 3 AEs were elevated liver enzymes (1 patient) in the continued EXE group, and gastritis, hypertriglyceridemia, and bone mineral density loss (1 patient each) in the EXE+CPA group.

Conclusion Switching from EXE monotherapy to EXE+CPA combination therapy based on clinical response and biological response (change in Ki67 index) to initial therapy improved subsequent clinical response in non-responders. Favorable clinical response to EXE alone was maintained in responders. Tailored neoadjuvant endocrine and chemo-endocrine therapy was shown to be effective in postmenopausal ER-positive breast cancer patients. (JBCRG-11CPA; UMIN000004751)

Citation Format: Masuda N, Sato N, Morimoto T, Ueno T, Kanbayashi C, Kaneko K, Yasojima H, Saji S, Sasano H, Morita S, Ohno S, Toi M. Tailored neoadjuvant endocrine and chemo-endocrine therapy for postmenopausal patients with estrogen receptor-positive human epidermal growth factor receptor 2-negative primary breast cancer [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 P3-13-06.

Abstract P6-11-17: Nanoparticle albumin-bound paclitaxel-induced peripheral neuropathy in patients receiving neoadjuvant or adjuvant chemotherapy for breast cancer

A brief background discussion.

Nanoparticle albumin-bound paclitaxel (nab-PTX) has been developed under the concept of improved drug delivery. nab-PTX has been shown to significantly increase progression-free survival compared with solvent-based paclitaxel (PTX) in metastatic breast cancer. However, the long-term outcomes of nab-PTX induced peripheral neuropathy (nPIPN) have not yet been fully elucidated.

Trial design: observational cohort study (UMIN20852)

Primary objective: The long-term outcome of nPIPN

Secondary objectives

(1)The validity of the Neuropathic Pain Screening Questionnaire (Japan–Q, Ishikawa et al. Pain Research 2016 )

(2) To evaluate the effect of frozen gloves and elastic stockings for nPIPN

nPIPN was assessed by the Japan-Q (J-Q) and Common Toxicity Criteria for Adverse Events ver 4.0 (CTC). The J-Q is an assessment tool for patient-reported pain severity, which consists of seven items, each rated on a five-point scale 0-4; grade 0 (no symptoms) to grade 4 (verysevere symptoms). Pricking pain, electric shock pain, burn like pain, tingling pain with numbness, allodynia, reduced or hyper sensitivity and hand-foot syndrome. Assessment was performed every day during chemotherapy, six months and one year after completion of nab-PTX therapy. Total of 28 points for each day and 588 points for each cycle, higher point correlates with severity. Frozen gloves during administration of nab-PTX and/or elastic stockings were optionally used.

Statistical methods

Kruskal Wallis test was used and p<0.05 was considered as significant.

RESULTS:

Between May 2013, and April 2016, 105 patients were enrolled from 7 hospitals. In 73 patients (69.5%) nab-PTX was administered as primary and in 32 patients (30.5%) as adjuvant therapy. Forty three (41.0%) patients received nab-PTX as first line and 62 (59.0%) received after anthracycline contained regimen. Trastuzumab was administered as combination therapy with nab-PTX for Her2 positive patients. Both frozen gloves and stockings were used in 21 patients (20.0%) and frozen gloves only were used in 21 patients (20.0%) according to patient preference.

One hundred patients (95.2%) completed four courses, and overall relative dose intensity was 91.4%.

During chemotherapy, J-Q scores go elevated from day 1 to day 5 and gradually declined throughout the rest of the cycle. Without using frozen gloves, there was a significant increase according to courses (1st: 45.0 ± 5.7, 2nd: 76.7 ± 8.6, 3rd: 94.3 ± 11.8, 4th: 95.4 ± 11.8). Using frozen gloves, there was a significant increase from 1st course to 2nd, but no further increase was observed(1st: 37.4 ± 8.1, 2nd: 61.9 ± 12.4, 3rd: 62.9 ± 10.4, 4th: 55.3 ± 10.6). After six month and one year, the scores were significantly lower compared with the last day of the fourth cycle (4.28 ± 0.50, 2.53 ± 0.25, 2.85 ± 0.39, respectively). CTC, grade 2 or more sensory disturbance was observed in 57.9% after four cycles, but improved to 9.5% and 5.4% after six month and one year respectively.

CONCLUSIONS:

Patient-reported nPIPN was significantly getting worse without frozen gloves during chemotherapy, however be largely reversible within 1 year of PST or adjuvant treatment. The J-Q findings support that nab-PTX treatment is tolerable.

Citation Format: Yoshidome K, Morimoto T, Matsunami N, Tsunashima R, Tsukamoto F, Ryo T, Nishida Y, Shimo T, Anno K, Shimada M, Udo M, Kagawa M, Morishima H, Oda N. Nanoparticle albumin-bound paclitaxel-induced peripheral neuropathy in patients receiving neoadjuvant or adjuvant chemotherapy for breast cancer [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 P6-11-17.

Abstract 91: Moyamoya Disease Susceptibility Gene, RNF213 p.R4810K Variant, is a Common Risk Factor for Atherothrombotic Brain Infarction in a Japanese Population

Background and Purpose: RNF213 has been identified as a susceptibility gene for moyamoya disease. The p.R4810K variant is found in about 80% of East Asian patients with moyamoya disease, and 20 - 25% of those with proximal intracranial arterial stenosis. In this study, we examined the association of RNF213 p.R4810K variant with non-cardioembolic stroke in a Japanese population.

Methods: We analyzed 383 consecutive patients with acute non-cardioembolic stroke, who were admitted to the National Cerebral and Cardiovascular Center from June 2012 to May 2017 and participated in NCVC Biobank, and 1011 healthy local Japanese controls. Patients diagnosed with moyamoya disease were excluded. Written informed consent was obtained from all study participants. Odds ratios (OR) and 95% confidence intervals (CI) were adjusted for age, sex, and conventional risk factors for stroke.

Results: The RNF213 p.R4810K variant was found in 5.2% of acute non-cardioembolic stroke patients and in 2.1% of healthy controls (adjusted OR 3.9, 95% CI 1.6 - 9.3, p=0.003). The mean age of stroke onset was lower in patients with the RNF213 p.R4810K variant than those without the variant (58.1±15.5 years vs. 69.1±13.2 years, p<0.001). Among stroke subtypes, only atherothrombotic brain infarction (ATBI) was significantly associated with this variant (adjusted OR 11.5, 95% CI 3.4 - 36.2, p<0.001, see also Table 1). When stratified by sex, these associations were more evident in women (Men: adjusted OR for ATBI 1.9, 95% CI 0.3 - 10.2, p=0.47; Women: adjusted OR for ATBI 58.0, 95% CI 10.3 - 327.3, p<0.001, see also Table 1).

Conclusion: The RNF213 p.R4810K variant is a genetic risk factor for non-cardioembolic stroke in Japan, especially for atherothrombotic brain infarction in women.

Abstract WP116: The Prevalence of RNF213 p.R4810K Variant is High in Juvenile–Onset Stroke Patients With Intracranial Arterial Stenosis

Background and purpose: RNF213 is a susceptibility gene for moyamoya disease (MMD) and over 90% of Japanese patients with MMD have the RNF213 p.R4810K variant. Recent studies have reported that 20 - 25% of East Asian patients with intracranial arterial stenosis also have the p.R4810K variant, while only about 2% of healthy Japanese population have the variant. In this study, we examined the prevalence of this variant in patients with juvenile-onset ischemic stroke.

Methods: This single-center cross-sectional study was completed at the National Cerebral and Cardiovascular Center, Osaka, Japan. We analyzed 70 Japanese patients who suffered ischemic stroke or TIA with intracranial arterial stenosis before their 60 th birthday. Patients with cardioembolic stroke or definite/probable MMD were excluded.

Results: The RNF213 p.R4810K variant was found in 24.2% of juvenile-onset stroke patients with intracranial arterial stenosis. This variant was found more often in women than in men (38% vs. 16%, OR 3.3, 95% CI 1.1-10.2, p=0.045). The variant was identified in 35% of the patients with stenosis in the M1 segment of the middle cerebral artery or the A1 segment of the anterior cerebral artery (OR 25.0, 95% CI 1.4-437.8, p<0.01), but in only one patient with intracranial posterior circulation stenosis (Table 1). When restricted to patients with multiple M1 or A1 stenoses, the variant prevalence increased to 56%. Conventional risk factors for stroke, such as smoking, hypertension, diabetes mellitus, dyslipidemia, and family history did not differ between patients with and without the variant.

Conclusion: The RNF213 p.R4810K variant is common for juvenile-onset ischemic stroke with M1 or A1 stenosis.

Mott transition by an impulsive dielectric breakdown

The transition of a Mott insulator to metal, the Mott transition, can occur via carrier doping by elemental substitution, and by photoirradiation, as observed in transition-metal compounds and in organic materials. Here, we show that the application of a strong electric field can induce a Mott transition by a new pathway, namely through impulsive dielectric breakdown. Irradiation of a terahertz electric-field pulse on an ET-based compound, κ-(ET) ₂Cu[N(CN) ₂]Br (ET:bis(ethylenedithio)tetrathiafulvalene), collapses the original Mott gap of ∼30 meV with a ∼0.1 ps time constant after doublon-holon pair productions by quantum tunnelling processes, as indicated by the nonlinear increase of Drude-like low-energy spectral weights. Additionally, we demonstrate metallization using this method is faster than that by a femtosecond laser-pulse irradiation and that the transition dynamics are more electronic and coherent. Thus, strong terahertz-pulse irradiation is an effective approach to achieve a purely electronic Mott transition, enhancing the understanding of its quantum nature.