Classification of the HCN isomerization reaction dynamics in Ar buffer gas via machine learning

The effect of the presence of Ar on the isomerization reaction HCN ⇄ CNH is investigated via machine learning. After the potential energy surface function is developed based on the CCSD(T)/aug-cc-pVQZ level ab initio calculations, classical trajectory simulations are performed. Subsequently, with the aim of extracting insights into the reaction dynamics, the obtained reactivity, that is, whether the reaction occurs or not under a given initial condition, is learned as a function of the initial positions and momenta of all the atoms in the system. The prediction accuracy of the trained model is greater than 95%, indicating that machine learning captures the features of the phase space that affect reactivity. Machine learning models are shown to successfully reproduce reactivity boundaries without any prior knowledge of classical reaction dynamics theory. Subsequent analyses reveal that the Ar atom affects the reaction by displacing the effective saddle point. When the Ar atom is positioned close to the N atom (resp. the C atom), the saddle point shifts to the CNH (HCN) region, which disfavors the forward (backward) reaction. The results imply that analyses aided by machine learning are promising tools for enhancing the understanding of reaction dynamics.

CDK actively contributes to establishment of the stationary phase state in fission yeast

Upon exhaustion of essential environmental nutrients, unicellular organisms cease cell division and enter stationary phase, a metabolically repressed state essential for cell survival in stressful environments. In yeast, cell size is reduced by cell division before entry into stationary phase; thus cyclin-dependent kinase (CDK) must actively contribute to stationary phase establishment. However, the contribution of CDK to stationary phase remains largely uncharacterized. Here, we examine the role of CDK in the establishment of stationary phase in fission yeast. We show that in stationary phase, nuclear and chromosomal volumes and the nucleus-to-cell volume ratio are reduced, and sister chromatid separation and chromosome fluctuation are repressed. Furthermore, CDK accumulates in the nucleolus. Most of these changes are induced by glucose depletion. Reduction in CDK activity before and upon stationary phase entry alleviates the changes and shortens the survival time of stationary phase cells, while CDK inhibition represses nucleolar CDK accumulation and glucose depletion-induced nuclear volume reduction. These results demonstrate that CDK actively regulates stationary phase, both before and upon stationary phase entry.

Prevalence and distribution of non-pulmonary vein atrial fibrillation triggers in real-world clinical settings

Background

Epidemiology of non-pulmonary vein (PV) triggers of atrial fibrillation (AF) is not fully known.

Purpose

This study aimed to clarify the prevalence and distribution of non-PV triggers in real-world clinical settings of AF catheter ablation.

Methods

One-thousand and twenty patients undergoing AF ablations were retrospectively analyzed (mean age 65 years old, 702 males (69%), 506 paroxysmal and 514 non-paroxysmal). Induction and observation of AF triggers were attempted using intravenous isoproterenol/adenosine triphosphate and repeated direct current cardioversion during AF in each session. Documentable non-PV AF triggers were characterized in the studied population. Premature atrial contractions that did not initiate AF were excluded.

Results

A hundred and twenty-six non-PV triggers were documented in 108 patients (10.6%). Non-PV trigger was documented in 6.3% of 1st session cases, whereas 30.9% of recurrent cases undergoing multiple sessions (p<0.0001). Left atrial (LA) posterior wall was the most prevalent site (N=34), followed by 30 intra-atrial septum (IAS), 29 superior vena cava (SVC), 13 crista terminalis, 7 right atrial (RA) free wall, 6 LA anterior wall, 3 coronary sinus (CS), 3 left atrial appendage, and 1 persistent left superior vena cava (LSVC). We classified those non-PV triggers into 4 groups; 43 LA, 33 thoracic veins (SVC, CS and LSVC), 30 IAS and 20 RA. Thoracic vein/RA origins were more prevalently detected in paroxysmal AF cases (57%) compared to non-paroxysmal AF (28%) (p<0.01). Conversely, LA origin was more prevalently detected in non-paroxysmal AF cases (48%) compared to paroxysmal AF (20%) (p<0.01).

Conclusions

Prevalence of non-PV trigger in cases undergoing multiple sessions is extremely high, suggesting a particular importance of non-PV trigger targeting in patients with recurrent AF undergoing 2nd or 3rd ablation sessions. Progressive nature of AF with newly generated AF triggers should be under consideration. Distributions of non-PV triggers are largely different between paroxysmal and non-paroxysmal AF. These findings may help ablation strategy regarding non-PV trigger targeting in practice.

Funding Acknowledgement

Type of funding sources: None.

Catheter ablation of persistent atrial fibrillation with heart failure improves hemodynamic status without deteriorating renal function in the elderly

Background/Introduction

Atrial fibrillation (AF) and heart failure (HF) frequently coexist in the elderly people, leading to worse clinical outcomes. HF with preserved ejection fraction (HFpEF) is the most common form of HF in the elderly, particularly in women, associated with AF. Ablation of AF in younger patients with HF with reduced EF (HFrEF) has become an established treatment option. However, clinical impact of ablation for persistent AF accompanying with HF in the elderly remains unclear.

Purpose

This study aimed to evaluate the effect of catheter ablation of persistent AF with heart failure in the elderly.

Methods

Consecutive 70 patients who underwent catheter ablation of persistent AF accompanying with HF (NYHA class> II, mean LVEF 51.7%) in our institution were retrospectively analyzed with regards to their 1-year clinical outcomes, HF markers such as BNP, renal function and transthoracic echocardiographic findings. Patients were dichotomized by age of 75-year-old (31 elderly vs 39 younger subjects) and separately analyzed.

Results

Mean age of the studied population was 70.5 year-old; 79.6±3.8 in the elderly group and 63.2±8.5 in the younger group. The elderly patients were more frequently females (45% vs 21%). Longstanding persistent AF was observed in 32% in the elderly and 28% in the younger group. Circumferential pulmonary vein isolation (PVI) was performed in all patients, with additional ablations of liner lesions and/or non-PV foci as needed. PVI alone was observed in 54.8% in the elderly and 41% in the younger group. There were no serious complications associated with the procedure. During 1 year after ablation, recurrence of AF was observed in 15 patients [6/31 (19%) in the elderly, 9/39 (23%) in the younger]. Readmission due to HF was observed in only 1 patient in the elderly and 2 patients in the younger group (3% vs. 5%, respectively). Cardiovascular events were observed in 3 patients [2/31 (6%) in the elderly, 1/39 (3%) in the younger], but there was no death. The BNP level as well as the NYHA class significantly decreased at 1-year follow-up compared to baseline in the both groups (Figure A and B). There was no change in serum creatinine level in the both groups (Figure C). The left atrial dimension and the LA volume index decreased at 1-year follow-up in the both groups (Figure D and E). The LVEF improved only in the younger group (Figure F).

Conclusions

Ablation of persistent AF in the elderly with HF (mostly with preserved EF) was associated with hemodynamic and functional improvements without deteriorating renal function in a mid-term, which was mostly comparable to the results in the younger.

Funding Acknowledgement

Type of funding sources: None.

Aggressive combined pharmacotherapy for heart failure reduces new onset atrial fibrillation

Backgrounds

Heart failure (HF) is a risk factor for new onset atrial fibrillation (AF), and the new onset AF is associated with a worse prognosis in HF patients. It has been reported that renin-angiotensin system inhibitor (RASi), β-blocker and mineral-corticoid receptor antagonist (MRA) prevent the new onset AF in HF patients. However, the effect of combined pharmacotherapy including angiotensin receptor neprilysin inhibitor (ARNI) and sodium glucose co-transporter 2 inhibitor (SGLT2i) on AF is unknown. We investigated the impact of contemporary regimen of combined pharmacotherapy for HF (RASi/ARNI+β-blocker+MRA+SGLT2i) on new onset AF.

Methods and results

We retrospectively studied rEF and mrEF patients without AF admitted to our hospital due to decompensated HF between 2015 and 2021 (n=366). Long-term (The mean follow-up was 635±421 days) incidence of new onset AF was investigated with regard to medical therapies. Patients were divided into 2 groups; patients with ≤2 HF drugs (n=181) and patients with ≥3 HF drugs (n=185). Patients with ≤2 HF drugs group were older (77.3 vs 67.0 years old, P<0.001), had a poorer renal function (Cre: 1.66 vs 1.09 mg/dl, P<0.001), and had a higher rate of ischemic heart disease (52 vs 38%, P=0.009), whereas left ventricular systolic function was better (EF: 31.9 vs 27.3%, P<0.001). There were 19 (10.5%) new onsets AF in the ≤2 HF drugs group, whereas only 7 (3.8%) had new onsets AF in the ≥3 HF drugs group (HR 0.36, 95% CI 0.15–0.85, P=0.01). All-cause death and hospitalization for HF were fewer in the ≥3 HF drugs group. A multivariate analysis revealed that ≥3 HF drugs use was an independent negative predictor of new onset AF (HR 0.37, 95% CI 0.15–0.93, P=0.03). Even after a propensity score matching of the clinical variables, the incidence of new onset AF was consistently fewer in the ≥3 HF drugs group (HR 0.36, 95% CI 0.13–0.99, P=0.04). Finally, patients with new onset AF had a higher rate of hospitalization for HF in the studied population (HR 9.68, 95% CI 5.67–16.5, P<0.01).

Conclusion

Aggressive combined pharmacotherapy for HF may be associated with fewer new onset AF in patients with HF.

Funding Acknowledgement

Type of funding sources: None.

Reduction of Pneumocystis jirovecii pneumonia and bloodstream infections by trimethoprim-sulfamethoxazole prophylaxis in patients with rheumatic diseases

Objective: Trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis against Pneumocystis jirovecii pneumonia (PJP) is routinely administered to patients with rheumatic diseases in Japan. The present study aimed to evaluate the effect of TMP/SMX prophylaxis on PJP and non-central line-associated bloodstream infections (BSIs) in patients receiving high-dose glucocorticoids for the treatment of rheumatic diseases.Method: This study enrolled patients who were admitted between 1 October 2003 and 31 March 2018 and began high-dose glucocorticoid therapy for rheumatic diseases during hospitalization. The observation period was 4 months from the commencement of high-dose glucocorticoid therapy. The effect of TMP/SMX prophylaxis on PJP and non-central line-associated BSI was analysed.Results: Of the 437 patients included in the study, 376 received TMP/SMX prophylaxis and 61 patients did not. During the observation period, TMP/SMX prophylaxis was discontinued in 76 patients (20.2%). Three PJP cases (0.7%) occurred. Among the 399 patients included in our analysis of non-central line-associated BSI, eight experienced non-central line-associated BSI (2.0%). Among the covariates, TMP/SMX prophylaxis was associated with reduced PJP and non-central line-associated BSI incidence [odds ratio (OR) 0, 95% confidence interval (CI) 0.00-0.38, and OR 0.08, 95% CI 0.01-0.42, respectively].Conclusion: Routine TMP/SMX prophylaxis reduced the incidence of both PJP and BSI in patients with rheumatic diseases undergoing high-dose glucocorticoid therapy.

Chiasmata and the kinetochore component Dam1 are crucial for elimination of erroneous chromosome attachments and centromere oscillation at meiosis I

Establishment of proper chromosome attachments to the spindle requires elimination of erroneous attachments, but the mechanism of this process is not fully understood. During meiosis I, sister chromatids attach to the same spindle pole (mono-oriented attachment), whereas homologous chromosomes attach to opposite poles (bi-oriented attachment), resulting in homologous chromosome segregation. Here, we show that chiasmata that link homologous chromosomes and kinetochore component Dam1 are crucial for elimination of erroneous attachments and oscillation of centromeres between the spindle poles at meiosis I in fission yeast. In chiasma-forming cells, Mad2 and Aurora B kinase, which provides time for attachment correction and destabilizes erroneous attachments, respectively, caused elimination of bi-oriented attachments of sister chromatids, whereas in chiasma-lacking cells, they caused elimination of mono-oriented attachments. In chiasma-forming cells, in addition, homologous centromere oscillation was coordinated. Furthermore, Dam1 contributed to attachment elimination in both chiasma-forming and chiasma-lacking cells, and drove centromere oscillation. These results demonstrate that chiasmata alter attachment correction patterns by enabling error correction factors to eliminate bi-oriented attachment of sister chromatids, and suggest that Dam1 induces elimination of erroneous attachments. The coincidental contribution of chiasmata and Dam1 to centromere oscillation also suggests a potential link between centromere oscillation and attachment elimination.

Presence of low voltage area predicts atrial tachyarrhythmia inducibility with atrial burst pacing after pulmonary vein isolation

Background

Induction of atrial fibrillation (AF)/atrial tachycardia (AT) by atrial burst pacing following ablation procedure may reflect the presence of residual substrates in the atria that maintain AF. However, the relation between the inducibility and left atrial low voltage area (LVA) has not been established.

Methods

Fifty-nine patients (65 years old, 43 males) with persistent AF who underwent pulmonary vein isolation (PVI)-based ablation were studied. All patients underwent left atrial voltage mapping during sinus rhythm and atrial burst pacing after PVI. Atrial burst pacing was performed with 30-beat at an amplitude of 10V from the ostium of the coronary sinus; increasing from 240 to 320 ppm in steps of 20 ppm or failure to 1:1 atrial capture. Inducibility was defined as AF/AT lasting more than 5 minutes following burst pacing. Left atrial LVA and other co-variates were analyzed with regard to burst pacing positivity.

Results

AF/AT was induced by burst pacing in 23 patients (39%). Univariate analysis revealed that past history of stroke, CHADS2 score and presence of left atrial LVA were significantly associated with the inducibility of AF/AT. Multivariate analysis revealed that only the presence of LVA was associated with the inducibility (OR 1.5: per 10% increase; p=0.04). We focused on the relationship between the extent of LVA and burst positivity. AF/AT inducibility increased as low voltage area increased, and it was as high as 72.7% when low voltage area was more than 20% (P<0.05). Interestingly, induced arrhythmia type was AT rather than AF when low voltage area was more than 20%.

Conclusions

Presence of left atrial LVA is an independent predictor of atrial tachyarrhythmia inducibility after PVI in patients with persistent AF. A large amount of low voltage area is related to AT inducibility rather than AF.

Extent of LVA and burst positivity

Funding Acknowledgement

Type of funding source: None

Early follow-up visit at outpatient care after discharge improves 2-year heart failure readmission rate and long-term prognosis in patients with decompensated heart failure

Background/Introduction

It has been reported that heart failure (HF) readmission has not declined even with current cardiology practice in the last 10 years. It has been also reported that HF readmission tends to occur shortly after discharge. This may be due to overwork and excessive salt intake after discharge. In other words, it is conceivable that patient factors are largely attributable, which should be intervene for better clinical outcomes.

Purpose

We hypothesized and investigated whether an early follow-up visit at outpatient care within 2 weeks after discharge affects the re-admission rate and prognosis in patients with decompensated HF.

Methods

We retrospectively investigated consecutive 407 hospitalized patients due to decompensated HF. After exclusion of 99 patients with in-hospital death, transfer to another hospital and readmission within 2 weeks after discharge, consecutive 308 out of 407 patients were investigated. Two-year clinical outcomes after discharge were collected and analyzed. An early follow-up was defined as an outpatient care visit within 2 weeks after discharge with the adjustment of drugs and/or the lifestyle guidance, if necessary. A setting of early follow-up in each patient was according to a physician's discretion.

Results

One hundred-twenty eight patients underwent early follow-up visits and other 180 patients were without it. An univariate analysis showed that the early follow-up was significantly associated with a lower HF readmission rate during 2 years (17.1% in the early follow-up group, 34.4% in the control group, p≤0.001, OR=0.397, 95% CI=0.230–0.685, Figure) and a 2-year composite adverse outcome (all cause death and HF readmission; 18.7% vs. 40.5%, p<0.001, OR=0.332, 95% CI=0.196–0.563, Figure). To exclude possible relationships of other co-variable factors, we performed a multivariate analysis about the association with HF readmission rate and the 2-year composite adverse outcome (co-variate factors as follows are included; factors of which p-value was less than 0.1 and general confounding factors). The multivariate analysis showed that the early follow-up was independently associated with HF readmission during 2 years (p=0.002, OR=0.376, 95% CI=0.197–0.716) and the 2-year composite outcome (p<0.001, OR=0.343, 95% CI=0.182–0.648). Finally, we characterized the practical interventions at outpatient care after discharge. Lifestyle guidance was done in all patients. However, medication adjustments were done in only 36.7% patients. Interestingly, whether or not a medication adjustment was done at the early follow-up visit was not associated with the HF readmissions (p=0.781).

Conclusions

The present study suggests that an early follow-up approach after discharge in decompensated HF patients may improve the long-term prognosis. These results were not dependent on whether a medication adjustment was performed or not. An early follow-up may help improve patient factors of HF worsening.

Main results

Funding Acknowledgement

Type of funding source: None

P3764Morphological mechanisms of atrial functional mitral regurgitation in patients with atrial fibrillation

Background

Atrial functional mitral regurgitation (AFMR) occurs in patients with atrial fibrillation. However, morphological mechanisms of AFMR are poorly understood.

Purpose

The purpose of this study was to examine the morphological characteristics in patients with AFMR.

Methods

Among consecutive 795 patients undergoing initial radiofrequency catheter ablation (RFCA) at our hospital, twenty-five patients with persistent AF accompanied by AFMR (≥ moderate) before RFCA (AFMR group) were studied. Age-matched 25 patients with persistent AF without MR were defined as a control group.

Results

Left ventricular ejection fraction (LVEF) was lower and left atrium volume index was larger in the AFMR group (Table). Mitral valve annulus diameter and length of anterior mitral leaflet (AML) were similar between groups, whereas length of posterior mitral leaflet (PML) was significantly shorter in the AFMR group. Smaller tethering angle of AML (γ in the figure) and shorter tethering height were significantly associated with the occurrence of AFMR, which were different from morphology of functional mitral regurgitation in patients with dilated LV. Multiple regression analysis revealed that less tenting height (p<0.05) and LA dilatation toward the posterior (p<0.01) were significantly related to AFMR.

Echocardiographic parameters AFMR (n=25) Control (n=25) P value Age, y 69±8 66±10 NS Male, n (%) 9 (36) 20 (80) P=0.001 LVEF,% 60±9 67±6 P=0.004 LAD, mm 44±5 41±7 NS LAVI, ml/m2 56±17 41±13 P<0.001 MV diameter, mm 3.9±0.4 3.8±0.5 NS α angle, ° 34±9 35±7 NS β angle, ° 48±9 50±8 NS γ angle, ° 32±5 37±5 P=0.0005 AML length, mm 3.0±0.5 3.0±0.5 NS PML length, mm 2.1±0.1 2.4±0.1 P=0.03 Tenting height, mm 1.5±0.1 1.8±0.1 P=0.02 D, mm 0.8±0.3 0.5±0.3 P=0.001 LVEF: left ventricular ejection fraction; LAD: left atrial diameter; LAVI: left atrial volume index; AML: anterior mitral leaflet; PML: posterior mitral leaftlet.

Conclusions

AFMR occurs in patients with unique morphological features, such as less tethering height and LA dilatation toward the posterior.

P1025Clinical predictors for the improvement of left ventricular ejection fraction and prognosis after catheter ablation of atrial fibrillation in patients with systolic dysfunction

Background

Catheter ablation (CA) of atrial fibrillation (AF) improves left ventricular ejection fraction (LVEF) and clinical outcomes in patients with left ventricular systolic dysfunction (LVSD). However, predictors of the improvement of LV function and clinical outcomes by CA were poorly understood.

Purpose

We examined the efficacy of CA in AF patients with LVSD and predictive factors associated with clinical outcomes.

Method

Among consecutive 795 patients undergone initial RFCA at our hospital, we studied 51 patients with LVSD (LVEF ≤50%). Improved LVEF more then 5% at 1-year after CA was classified as “responder” to CA. We analyzed clinical variables and echocardiographic parameters before and after the CAs.

Results

In the responder group, LVEF was significantly improved 1-year after catheter ablation compared with the non-responder group. (ΔLVEF 22±12% vs. −1±4%, p<0.001). The responder group was significantly younger, had more non-paroxysmal AF, smaller LV systolic diameter and lower plasma BNP level before CA (Table). Late gadolinium enhancement (LGE)-positive rate in cardiovascular magnetic resonance imaging (CMR) before CA was higher in the non-responder group than in the responder group (100% [6/6] vs. 38% [5/13], p<0.005). After CAs of AF, event-free survival from hospitalization for heart failure was significantly higher in the responder group (Figure) with less AF recurrence (27% vs. 47%, p=0.04) than in the non-responder group.

Baseline characteristics Responder (N=35) Non-Responder (N=16) P value Age, y 62±11 69±8 p<0.01 Male, n (%) 26 (74) 13 (76) NS Non-pAF 26 (74) 4 (24) p<0.01 LAD, mm 48±7 48±8 NS LAVI, ml/m2 54±17 58±20 NS LVDd, mm 54±7 58±10 NS LVDs, mm 43±7 48±10 p=0.05 EF, % 37±8 38±8 NS BNP (pg/ml) 278±225 684±848 p<0.05

Conclusion

Younger age, absence of LV dilatation, lower plasma BNP, or absence of LGE may well predict favorable clinical outcomes after CA in patients with LVSD.

Graft Immunocomplex Capture Fluorescence Analysis Can Detect Intragraft Anti-Major Histocompatibility Complex Antibodies in Mice Cardiac Transplant

BACKGROUND

Immunocomplex capture fluorescence analysis has recently been applied as a method for detection of intragraft donor-specific anti-major histocompatibility complex (MHC) antibodies (DSA) in humans. Although intragraft DSA in humans is an intense topic of investigation, there is no report to assess intragraft DSA in murine organ transplantation.

METHODS

A model of presensitized mouse cardiac transplantation by donor splenocytes was used. To capture mouse MHC, anti-MHC class I/II antibodies were immobilized on Luminex beads. The MHC/DSA complexes were captured by the Luminex beads followed by detection of phycoerythrin-conjugated antimouse IgG antibodies where DSA had already reacted with the allograft in vivo.

RESULTS

Luminex beads were capable of detecting class I DSA in the cardiac allograft, though results for class II DSA were negative. Immunohistochemical investigation revealed that cardiac allografts had abundant MHC class I expression but only minor expression of MHC class II. Furthermore, MHC/class II DSA complexes were successfully detected in splenocytes and serum from a presensitized recipient.

CONCLUSIONS

These data suggested that graft immunocomplex capture fluorescence analysis can be also applied in murine cardiac transplantation. This novel application in mice would accelerate our comprehension of DSA through mechanistic studies.

Abstract P1-15-12: Axillary lymph node metastasis and HER2-receptor positivity significantly associate with recurrence and worse survival in breast cancer patients who achieved pathological complete response after neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy (NAC) has become a common practice in breast cancer care since it not only expands the opportunity for breast conservation surgery, but also allows in vivo assessment of individual cancer biology. Patients who achieved pathological complete response (pCR) after NAC are known to have significantly improved outcomes than those who did not. To date, there has been no large study of factors that associate with tumor recurrence after patients had pCR following NAC. To identify such factors, we examined a cohort of 394 patients.

METHODS

Patients diagnosed during 2007-16 with clinical stage I-III breast cancer who achieved pCR following NAC were identified from clinical records at four hospitals in urban Japan. Nearly 70% of patients received standard NAC regimen, which was a combination of anthracycline and taxane, with trastuzumab added as needed. pCR was defined as no pathological evidence of invasive cancer in the breast; residual ductal carcinoma in situ (DCIS) and residual axillary lymph node metastasis were included in this study. The median follow-up time was 63 months (range = 16-161 months). Outcomes were assessed by 5-year disease-free survival (DFS) and 5-year overall survival (OS).

RESULTS

Among the 394 patients with pCR, the breast cancer subtype was as follows: Luminal – 49 (12.4%), Luminal-HER2 – 97 (24.6%), HER2 – 117 (29.7%), and TNBC – 131 (33.2%). During follow up, 28 (7.1%) of the 394 patients had experienced tumor recurrence. In univariate Cox regression analysis, each of HER2-receptor status, pre-NAC tumor size, and pre-NAC axillary lymph node status were associated with recurrence. The hazard ratios, and their 95% confidence intervals (CI) and P values for these significant factors were as follows. HER2-receptor negative vs. positive: 2.5 (CI = 1.0-5.8; P = 0.036); cT1/2 vs. cT3/4: 2.2 (CI = 1.3-6.1; P = 0.008); cN0 vs. cN1-3: 9.5 (2.2-40.7; P = 0.002). However, age (&lt;50 vs. ≥50 y), residual DCIS, post-NAC axillary lymph node status, type of mastectomy (total vs. partial), and adjuvant radiation therapy were not associated with recurrence. Of the 28 patients with recurrence, site of first event was local for 8, and brain and visceral for 10 each. Seven of the 10 patients with brain metastasis were HER2-receptor positive. Eleven of the 28 patients with recurrence had deceased, with a median post-recurrence survival duration of 40 months (range = 2–94 months). Shorter survival was associated with HER2-receptor positivity (P = 0.003).

CONCLUSION

Axillary lymph node metastasis before rather than after NAC, and HER2-receptor positivity are associated with tumor recurrence in patients who achieved pCR in breast cancer. HER2-receptor positive patients had higher risk for brain metastasis and shorter survival. Given the extreme rarity of local recurrence after pCR, we cannot help but speculate that omitting surgical removal of pCR tissue may be permissible when pCR has been diagnosed accurately.

Citation Format: Asaoka M, Narui K, Suganuma N, Chishima T, Yamada A, Kawai S, Uenaka N, Sato E, Katsuta E, Kawaguchi T, Takabe K, Ishikawa T. Axillary lymph node metastasis and HER2-receptor positivity significantly associate with recurrence and worse survival in breast cancer patients who achieved pathological complete response after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-12.

Regression Analysis for Nucleation-Elongation Model of Supramolecular Assembly: How To Determine Nucleus Size

Nucleation-elongation is known to give satisfactory descriptions of many supramolecular polymerization systems in thermal equilibrium. Its key feature is the necessity to form a "nucleus" consisting of a certain number of monomer units before being able to grow into a longer polymer chain. The size of the nucleus has significant implications for the understanding of the supramolecular polymerization mechanism. Here we investigate how experiments can give information on the nucleus size by regression analysis of various types of measurements. The measurements of free monomer concentrations, diffusion coefficients, and calorimetric response as functions of concentration or temperature are considered. The nucleation-elongation model with a general value for the nucleus size is used to provide mathematical expressions for these experimental observables. Numerical experiments are performed where experimental errors are simulated by computer-generated random numbers, and it is investigated whether least-squares fitting analyses can give the correct values of the nucleus size in the presence of experimental errors. It is recommended that the calorimetric measurements such as differential scanning calorimetry (DSC) or isothermal titration calorimetry (ITC) be performed under various conditions to correctly determine the nucleus size experimentally.

Reappraisal of classification of distal cholangiocarcinoma based on tumour depth

Background

In the eighth edition of the AJCC cancer staging classification, the T system for distal cholangiocarcinoma (DCC) has been revised from a layer-based to a depth-based approach. The aim of this study was to propose an optimal T classification using a measured depth in resectable DCC.

Methods

Patients who underwent pancreatoduodenectomy for DCC at 32 hospitals between 2001 and 2010 were included. The distance between the level of the naive bile duct and the deepest cancer cells was measured as depth of invasion (DOI). Invasive cancer foci were measured as invasive tumour thickness (ITT). Log rank χ2 scores were used to determine the cut-off points, and concordance index (C-index) to assess the survival discrimination of each T system.

Results

Among 404 patients, DOI was measurable in 182 (45·0 per cent) and ITT was measurable in all patients, with median values of 2·3 and 5·6 mm respectively. ITT showed a positive correlation with DOI (rs = 0·854, P &lt; 0·001), and the cut-off points for prognosis were 1, 5 and 10 mm. Median survival time was shorter with increased ITT: 12·4 years for ITT below 1 mm, 5·2 years for ITT at least 1 mm but less than 5 mm, 3·0 years for ITT at least 5 mm but less than 10 mm, and 1·5 years for ITT 10 mm or more (P &lt; 0·001). This classification exhibited more favourable prognostic discrimination than the T systems of the seventh and eighth editions of the AJCC (C-index 0·646, 0·622 and 0·624 respectively).

Conclusion

ITT is an accurate approach for depth assessment in DCC. The four-tier ITT classification with cut-off points of 1, 5 and 10 mm seems to be a better T system than those in the seventh and eighth editions of the AJCC classification.

Sphingomyelin Phosphodiesterase 3 Enhances Cytodifferentiation of Periodontal Ligament Cells

Sphingomyelin phosphodiesterase 3 ( Smpd3), which encodes neutral sphingomyelinase 2 (nSMase2), is a key molecule for skeletal development as well as for the cytodifferentiation of odontoblasts and alveolar bone. However, the effects of nSMase2 on the cytodifferentiation of periodontal ligament (PDL) cells are still unclear. In this study, the authors analyzed the effects of Smpd3 on the cytodifferentiation of human PDL (HPDL) cells. The authors found that Smpd3 increases the mRNA expression of calcification-related genes, such as alkaline phosphatase (ALPase), type I collagen, osteopontin, Osterix (Osx), and runt-related transcription factor (Runx)-2 in HPDL cells. In contrast, GW4869, an inhibitor of nSMase2, clearly decreased the mRNA expression of ALPase, type I collagen, and osteocalcin in HPDL cells, suggesting that Smpd3 enhances HPDL cytodifferentiation. Next, the authors used exome sequencing to evaluate the genetic variants of Smpd3 in a Japanese population with aggressive periodontitis (AgP). Among 44 unrelated subjects, the authors identified a single nucleotide polymorphism (SNP), rs145616324, in Smpd3 as a putative genetic variant for AgP among Japanese people. Moreover, Smpd3 harboring this SNP did not increase the sphingomyelinase activity or mRNA expression of ALPase, type I collagen, osteopontin, Osx, or Runx2, suggesting that this SNP inhibits Smpd3 such that it has no effect on the cytodifferentiation of HPDL cells. These data suggest that Smpd3 plays a crucial role in maintaining the homeostasis of PDL tissue.

Recovering hidden dynamical modes from the generalized Langevin equation

In studying large molecular systems, insights can better be extracted by selecting a limited number of physical quantities for analysis rather than treating every atomic coordinate in detail. Some information may, however, be lost by projecting the total system onto a small number of coordinates. For such problems, the generalized Langevin equation (GLE) is shown to provide a useful framework to examine the interaction between the observed variables and their environment. Starting with the GLE obtained from the time series of the observed quantity, we perform a transformation to introduce a set of variables that describe dynamical modes existing in the environment. The introduced variables are shown to effectively recover the essential information of the total system that appeared to be lost by the projection.

Early results of multicenter phase II trial of perioperative oxaliplatin and capecitabine without radiotherapy for high-risk rectal cancer: CORONA I study

BACKGROUNDS

Perioperative introduction of developed chemotherapy into the treatment strategy for locally advanced rectal cancer (LARC) may be a promising option. However, the most prevalent treatment for high-risk LARC remains preoperative chemoradiotherapy (CRT) in Western countries.

PATIENTS AND METHODS

A phase II trial was undertaken to evaluate safety and efficacy of perioperative XELOX without radiotherapy (RT) for patients with high-risk LARC. Patients received 4 cycles of XELOX before and after surgery, respectively. Primary endpoint was disease-free survival.

RESULTS

We enrolled 41 patients between June 2012 and April 2014. The completion rate of the preoperative XELOX was 90.3%. Twenty-nine patients (70.7%) could start postoperative XELOX, 15 of these patients (51.7%) completed 4 cycles. Allergic reaction to oxaliplatin was experienced by 5 patients (17.2%) during postoperative XELOX. One patient received additional RT after preoperative XELOX. Consequently, the remaining 40 patients underwent primary resection. Major complications occurred in 6 of 40 patients (15.0%). Pathological complete response (pCR) rate was 12.2%, and good tumor regression was exhibited in 31.7%. N down-staging (cN+ to ypN0) and T down-staging were detected in 56.7% and 52.5%, respectively. Clinical T4 tumor was a predictor of poor pathological response (p < 0.001).

CONCLUSIONS

We could show the favorable pCR rate after preoperative XELOX alone. However, the T and N down-staging rate was likely to be insufficient. When tumor regression is essential for curative resection, the use of preoperative CRT is likely to be recommended. For patients with massive LN metastasis, the additional Bev to NAC might be a promising option.

Nucleotide Sequence of the Gene for an Alkaline Endoglucanase from an AlkalophilicBacillusand Its Expression inEscherichia coliandBacillus subtilis

The gene for an alkaline endoglucanase from the alkalophilic Bacillus sp. KSM-64 was cloned into the HindIII site of pBR322 and expressed in Escherichia coli HB101. The nucleotide sequence of a 4.1-kb region of the HindIII insert had two open reading frames, ORF-1 and ORF-2. The protein deduced from ORF-1 was composed of 244 amino acids with an M(r) of 27,865. Subcloning analysis proved that the alkaline endoglucanase was encoded by ORF-2 (822 amino acids with an M(r) of 91,040). Upstream from ORF-2, there were three consensus like sequences of the sigma A-type promoter of Bacillus subtilis, a putative Shine-Dalgarno sequence (AGGAGGT), and a catabolite repression operator-like sequence (TGTAAGCGGTTAACC). The HindIII insert was subcloned into a shuttle vector, pHY300PLK, and the encoded alkaline endoglucanase gene was highly expressed both in E. coli and B. subtilis. One of the three promoter-like sequences in ORF-2 could be suitable for high levels of enzyme expression in both host organisms.

Reactivity boundaries for chemical reactions associated with higher-index and multiple saddles

Reactivity boundaries that divide the origin and destination of trajectories are of crucial importance to reveal the mechanism of reactions, which was recently found to exist robustly even at high energies for index 1 saddles [Phys. Rev. Lett. 105, 048304 (2010)]. Here we revisit the concept of the reactivity boundary and propose a more general definition that can involve a single reaction associated with a bottleneck composed of higher-index saddles and/or several saddle points with different indices, where the normal form theory, based on expansion around a single stationary point, does not work. We numerically demonstrate the reactivity boundary by using a reduced model system of the H(5)(+) cation where the proton exchange reaction takes place through a bottleneck composed of two index 2 saddle points and two index 1 saddle points. The cross section of the reactivity boundary in the reactant region of the phase space reveals which initial conditions are effective in making the reaction happen and thus sheds light on the reaction mechanism.

Numerical construction of estimators for single-molecule fluorescence measurements

A novel scheme to estimate the values of the underlying physical quantity and those of any functions of the quantity from measured observable(s) contaminated with stochastic noise is presented for any arbitrary probability distribution. The constructed estimators can either maximize the unbiasedness (i.e., minimize the amount of the deviation of the expectation value from the true value buried in the measurement) or minimize the risk (the average deviation from the true value) depending on the relative priority of unbiasedness and risk in the data analysis. The performance of the constructed estimators is demonstrated with computer simulations of Förster-type resonance energy transfer (FRET) measurements and also with FRET experimental data of the agonist-binding domain of the GluA2 subunit of AMPA receptors with agonists chloro- and iodo-willardiines and with adenylate kinase both in the apo form and with substrates AMP-PNP and AMP. It is shown that the estimators constructed by the present method can quantify faithfully not only the physical quantity to be monitored but also the functions of that quantity for a wide range of values.