Difference in Radiosensitivity Depending on the Presence and Absence of EGFR Mutations: Clinical and In Vitro Analyses

PURPOSE/OBJECTIVE(S)

For stage IV non-small cell lung cancer (NSCLC), the treatment drug is selected based on the gene mutation status. However, the dose or field of radiation therapy is not change based on the genetic status. We evaluated both clinical and in vitro data, showing that the presence or absence of epidermal growth factor receptor (EGFR) mutations affects radiosensitivity in patients with brain metastases (BM) from NSCLC.

MATERIALS/METHODS

Patients with BM from NSCLC who received whole brain radiotherapy (WBRT) were enrolled in this study. Patient characteristics are shown in the Table. EGFR mutations were observed in 13 (31.0%) patients. The prescribed dose was 30 Gy in 10 fractions (85.7%). The A549, VMRC-LCD, NCI-H1975, and HCC4006 cell lines were used for the in vitro study. EGFR mutation was negative in A549 and VMRC-LCD and positive in NCI-H1975 (exon21) and HCC4006 (exon19). After irradiation of these cell lines with 0, 2, 4, and 8 Gy, a colony formation assay was performed. DNA double-strand breaks (DSBs) were assessed 30 min and 24 h after 4 Gy irradiation using γH2AX.

RESULTS

The median follow-up period was 4 months (range, 1-35). Intracranial recurrence was observed in 14 (33.3%) patients during the follow-up period. Thirty-nine (92.9%) patients died during the follow-up period. Patients with EGFR mutation-positive tumors had significantly better intracranial control rates than those with EGFR mutation-negative tumors (p = 0.0213). A similar tendency was observed in the analysis conducted, except for the cases in which tyrosine kinase inhibitor (TKI) was administered after WBRT. In the EGFR mutation-positive group, no significant difference was observed between patients who received TKI after WBRT and those who did not (p = 0.527). In the colony formation assay, EGFR mutation-positive cell lines showed a significantly lower number of colonies formed after irradiation with 2 and 4 Gy than mutation-negative cell lines (p = 0.00018 and 0.0000291, respectively). EGFR mutation-positive cell lines had significantly more DNA-DSBs remaining 24 h after irradiation than mutation-negative cell lines (p = 0.0000000312).

CONCLUSION

Our data suggest that patients with EGFR mutation-positive NSCLC are more radiosensitive than those with negative EGFR mutations.

Deep-Inspiration Breath-Hold Stereotactic Body Radiation Therapy by Combining Spirometer-Guided Breath-Hold and a Real-Time Tumor Tracking System: A Novel Approach

PURPOSE/OBJECTIVE(S)

There are several methods used against respiratory motion (RM). Expiratory breath-hold (BH) is considered more stable and reproducible than inspiratory BH; therefore, BH with spirometry is often used for expiration. The real-time tumor tracking radiotherapy (RTRT) system is a highly effective method for reducing the margin of RM. This system ambushes and irradiates tumors during the expiratory phase when tumors move slowly. Although these methods usually involve expiration, it is advantageous to expand the lungs with inspiration to reduce the risk of adverse events. Here, we developed a new approach of performing stereotactic body radiation therapy (SBRT) under deep-inspiration BH (DIBH) by combining these two methods.

MATERIALS/METHODS

Lung tumors with respiratory motion ≥ 1 cm were included. Three or four fiducial markers were placed near the tumor via bronchoscopy. DIBH CT (CT-IN) was performed under the guidance of spirometer. The PTV was obtained by adding a 5-mm margin to the GTV delineated on CT-IN. The prescribed dose was 42 Gy in four fractions for the D95 of the PTV. An error of 2.0 mm around the planned position of the fiducial marker on CT-IN was permitted along each orthogonal axis as a gating box. In preparation for cases in which the reproducibility of DIBH is low and treatment cannot be performed, light expiration BH CT (CT-EX) was also performed, and a radiotherapy plan was prepared for the conventional RTRT system so that it could be switched at any time. Lung volumes and doses (mean dose, V20 Gy, V10 Gy, and V5 Gy) on CT-EX and CT-IN were compared.

RESULTS

Five patients underwent SBRT with DIBH, and all completed the planned irradiation course. The median treatment time per fraction was 27.86 min (range, 25.5-40.6). Four tumors were located in the left lower lobe and one in the right lower lobe. The median volume of PTV was 12.4 (range, 5.2-26.2) mL. The lung volumes and doses on CT-EX and CT-IN are shown in the Table. The lung volume on CT-IN was 1.6 times larger than that on CT-EX. The PTV-to-lung ratio on CT-IN was significantly lower than that on CT-EX. V20 Gy and V10 Gy on CT-IN were significantly lower than those on CT-EX.

CONCLUSION

SBRT with DIBH was achieved by combining the spirometer and RTRT system. This can help to eliminate concerns about reproducibility and high-speed tumor movement during inspiration, which are weaknesses of spirometer-guided breath-hold and the RTRT system, respectively, while ensuring the accuracy of the RTRT system. DIBH SBRT is a promising method that can reduce lung dose.

Masticatory Behavior Change with a Wearable Chewing Counter: A Randomized Controlled Trial

Because a relationship has been reported between masticatory behavior, obesity, and postprandial blood glucose, it is recommended to chew well and take a longer time to eat. The purpose of this study was to examine the possibility of changing masticatory behavior using a small ear-hung wearable chewing counter, which can monitor masticatory behavior without disturbing daily meals. In total, 235 healthy volunteers participated in a 4-wk randomized controlled trial and were divided into 3 groups. All participants were instructed about the importance of mastication at the first visit. During the intervention, group B used the chewing counter without an algorithm during each meal (notification of the number of chews after meal), and group C used the chewing counter with a masticatory behavior change algorithm (setting a target value and displaying the number of chews in real time). Group A was set as the control group. The number of chews and the meal time when consuming 1 rice ball (100 g) were measured before and after the intervention using the chewing counter, and the rate of change in these values was evaluated. Participants also provided a subjective evaluation of their changes in masticatory behavior. The number of chews and the meal time of 1 rice ball increased significantly in groups B and C compared with before the intervention, and the rate of change was significantly higher in group C than in group A and group B. In addition, the subjective evaluation of the change in the number of chews was highest in group C. Self-monitoring of masticatory behavior by providing a target value and the degree of achievement for the number of chews using a wearable chewing counter with a behavioral change algorithm could promote effective change in masticatory behavior and lead to an increased number of chews. (Trial ID: UMIN000034476).

Relationship between Wearing a Lead Apron and Work-related Musculoskeletal Disorders: A Questionnaire Survey of Japanese Radiological Technologists

The purpose of this study was to conduct a self-reported questionnaire survey of work-related musculoskeletal disorders (WMSDs) among Japanese radiological technologists (RTs) and to report on the relationship between wearing a lead apron and WMSDs. Between February and April of 2021, RTs in Okayama Prefecture, Japan, were surveyed by mail and through a website. Information on individual characteristics, physical factors at work, and the presence of WMSDs were collected. All participants were also asked whether they frequently wore lead aprons. A multiple logistic regression analysis was used to assess the relationship between wearing a lead apron and WMSDs. The model was adjusted for age, sex, body mass index (BMI), and working hours. Of the 123 participants, 67 (54.5%) had WMSDs. Multiple logistic regression analysis revealed that WMSDs were significantly associated with wearing a lead apron. Compared to the "Never wear" group, the odds ratios for the "Always/Frequently wear" and "Sometimes/Rarely wear" groups were 7.87 (95% confidence interval [CI]=1.28-48.46; p=0.026) and 7.80 (95% CI=1.43-42.44; p=0.017), respectively. Our analysis suggests that wearing a lead apron is associated with WMSDs, and thus design modifications in lead aprons may improve the occupational health management of RTs.

Direct visualization of the three-dimensional shape of skyrmion strings in a noncentrosymmetric magnet

Magnetic skyrmions are topologically stable swirling spin textures that appear as particle-like objects in two-dimensional (2D) systems. Here, utilizing scalar magnetic X-ray tomography under applied magnetic fields, we report the direct visualization of the three-dimensional (3D) shape of individual skyrmion strings in the room-temperature skyrmion-hosting non-centrosymmetric compound Mn_1.4Pt_0.9Pd_0.1Sn. Through the tomographic reconstruction of the 3D distribution of the [001] magnetization component on the basis of transmission images taken at various angles, we identify a skyrmion string running through the entire thickness of the sample, as well as various defect structures, such as the interrupted and Y-shaped strings. The observed point defect may represent the Bloch point serving as an emergent magnetic monopole, as proposed theoretically. Our tomographic approach with a tunable magnetic field paves the way for direct visualization of the structural dynamics of individual skyrmion strings in 3D space, which will contribute to a better understanding of the creation, annihilation and transfer of these topological objects.

Hyperacute postprocedural high platelet reactivity: a novel predictor for in-hospital adverse events in acute coronary syndrome with prasugrel loading

Introduction

Postprocedural High platelet reactivity (HPR) seems to associate long term adverse cardiovascular events, mainly intrastent thrombosis. However, the relationship between hyper-acute postprocedural HPR with prasugrel loading and clinical outcomes in acute coronary syndrome (ACS) is still unclear. Moreover, factors contributing HPR in ACS with prasugrel loading are also unknown.

Purpose

This study aimed to assess the impact of hyper-acute postprocedural HPR with prasugrel loading on clinical outcomes in ACS during hospitalization, as well as to define appropriate cut-off values and identify contributing factors of HPR.

Methods

We performed a single-centre, retrospective observational study that enrolled 207 patients who underwent emergent PCI for ACS with prasugrel loading. The P2Y12reaction unit (PRU) value was measured immediately after PCI with the VerifyNow System. The primary endpoint was major adverse cardiac events (MACE, defined as the composite of death, myocardial infarction, stroke, heart failure, ventricular arrhythmia needing defibrillation).

Results

Mean patient age (standard deviation) was 70.5 (±13.0) years, 78.7% were male, and average time from prasugrel intake to PRU calculation was 98.3 (±49.1) min. During a mean hospital stay of 15.9 (±9.3) days, there were 34 in-hospital MACE (16.4%) and 10 deaths (4.8%). Thrombosis events, didn't stand out and mechanical complications, such as cardiac rupture and cardiac tamponade occupies most of cardiovascular death which occurred before 10 days on admission. PRU was significantly higher in MACE group than Non-MACE group (279±65 vs 227±72, p<0.001 respectively). The ROC curve analysis of PRU for discriminating significant in-hospital MACE showed the cut off value of 293 (sensitivity:52.9%, specificity:83.2% [AUC=0.709, p<0.0001]). 47patients (29.4%) were thus categorized as HPR (PRU>293) immediately after emergent PCI. Kaplan-Meyer curve showed MACE events occurred in HPR group than non-HPR group (38.2% vs 10.0%, p<0.001). Multiple cox analysis demonstrated that HPR was independent predictors of MACE in patients with ACS underwent PCI (OR 5.416, 95% CI 2.157–13.598, p<0.0001). Multiple logistic regression model showed female sex, low haemoglobin value, and large mean platelet volume were independent predictors of HPR.

Conclusion

PRU was significantly higher in MACE group, and appropriate cut-off value of HPR in this study was 293. HPR was independent predictor of MACE during hospitalization, however thrombosis event was not significant. Evidence of clinical impact with postprocedural HPR within 120 minutes after prasugrel loading is scarce. This study shows post-procedural HPR, even without sufficient time after prasugrel intake, can be a useful predictive marker of adverse events during hospitalization.

Funding Acknowledgement

Type of funding sources: None. PRU between Non-MACE and MACE groupKaplan-Meyer curve

Cardio-ankle vascular index is useful screening method to detect obstructive coronary artery disease in asymptomatic diabetes patients with subclinical atherosclerosis

Background

Patients with diabetes mellitus are at very high risk for obstructive coronary artery disease; however, invasive coronary angiography is not allowed to apply in all patients. Cardio-ankle vascular index (CAVI), a marker of arterial stiffness has been reported to reflect atherosclerotic burden.

Purpose

To assess the diagnostic performance of CAVI vs. coronary calcium score for detecting obstructive coronary artery disease determined by Coronary CT angiography (CCTA) in asymptomatic diabetes patients.

Methods

During May 2015 to December 2019, 816 patients with diabetes mellitus were evaluated. First, intima-media thickness of carotid artery was measured in all subjects. Then, patients with intima-media thickness over 11mm underwent CAVI. Finally, 209 patients who have one or more cardiovascular risk factors other than diabetes mellitus were enrolled (68±11 years, 68% men). Patients were excluded if they had a disorder of the kidney, a prior history of coronary artery revascularization, atrial fibrillation, LV ejection fraction <50%, ABI <0.9 or allergy to contrast. Diagnostic performance of CAVI was evaluated with coronary stenosis >50% by CCTA.

Results

CAVI, Agatston score, and intima-media thickness of carotid artery were 9.2±1.3, 396±621 and 2.0±0.7mm, respectively. CAVI was significantly correlated with age (r=0.530, p<0.001), coronary artery calcification (r=0.182, p=0.008), and intima-media thickness of carotid artery (r=0.195, p=0.005). Among them, 108 patients (48%) had coronary stenosis. CAVI, Agatston score and intima-media thickness of carotid artery in patients with coronary stenosis were higher than that without coronary stenosis, respectively (9.8±1.1 vs 8.5±1.0, p<0.001, 526±676 vs. 255±525, p=0.001, 2.2±0.7 vs. 1.8±0.6, p<0.001). The ROC curve analysis of CAVI for discriminating coronary stenosis showed that the sensitivity 75.0% and specificity 77.2% at the cut off value of 9.23 (AUC=0.812, p<0.001). Contrastingly, diagnostic performance of coronary calcium score and intima-media thickness of carotid artery were less than CAVI (sensitivity: 91.7%, specificity: 56.4%, AUC=0.753, p<0.05 vs. CAVI, sensitivity: 68.5%, specificity: 59.4%, AUC=0.663, p<0.05 vs. CAVI). Multivariate logistic analysis demonstrated that CAVI was significantly associated with coronary stenosis (OR=4.133, p<0.001) after adjustment of conventional risk factors, although coronary calcium score was not correlated with coronary stenosis.

Conclusion

CAVI could be informative to select patients having obstructive coronary artery disease in asymptomatic diabetes patients with thick intima-media thickness.

Funding Acknowledgement

Type of funding sources: None.

Impact of high platelet reactivity on left ventricular remodeling in patients with acute coronary syndrome

Background/Introduction

Previous studies demonstrated that high platelet reactivity (HPR) predicts future cardiovascular death and coronary events in patients undergoing percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). However, few studies have focused on the impact of HPR on left ventricular remodeling (LVR) and each echocardiographic parameter.

Purpose

The purpose of this study was to investigate the impact of HPR in ACS patients on LVR and changes in echocardiographic volume indexes and LV ejection fraction.

Methods

This is a retrospective cohort study of prospectively collected data in a single center that enrolled patients who underwent emergency PCI for ACS including STEMI and NSTEMI with prasugrel loading. The primary outcome of the study was LVR associated with HPR. Secondary endpoints were changes in indexed LVESV, LVEDV, LVEF, E/e' and LAVI between baseline and follow-up. The P2Y12 reaction unit (PRU) value in response to prasugrel was assessed by the VerifyNow P2Y12 assay. Blood samples were collected once per procedure immediately after PCI. LVR index was calculated as the relative change in LVEDV observed at follow-up compared with baseline. LVR was defined as a relative increase in LVEDV ≥20%, measured at follow-up visit compared with the baseline value before discharge.

Results

A total of 196 ACS patients who underwent emergency PCI between January 2016 and July 2020 were enrolled in the study. The mean age of the study population was 69.9 years, and 76.0% were male. On echocardiography at follow up visit of mean duration of 7.0±4.0 months, LVR was found in 38 patients (19.4%). The optimal cutoff for PRU associated with increased LVR assessed by receiver-operating characteristic curve analysis was 245.5 (AUC: 0.656; 95% CI: 0.564 to 0.749; p=0.003). On the basis of this cutoff, HPR was found in 82 patients (42.1%) and the prevalence of LVR was significantly higher in the HPR group compared to the non-HPR group (30.5% vs. 11.4%; p=0.001). Multiple Cox regression analysis showed that HPR was an independent predictor of LVR (OR 4.22, 95% CI 1.83–9.71, p=0.001). In addition, Δ% EDV and Δ% ESV increased in the HPR group, and decreased in the non-HPR group with significant differences (5.8±32.6% vs. −8.0±26.2% in Δ% EDV; p=0.002, 2.0±37.5% vs. −13.3±33.0% in Δ% ESV; p=0.004, respectively). Δ%EF, Δ%E/e', Δ%LAVI were numerically improved in the non-HPR group compared with the HPR group, but this difference did not reach statistical significance.

Conclusion

In patients with ACS, HPR defined as PRU ≥246 immediately after emergency PCI was an independent predictor of LVR in the chronic phase.

Funding Acknowledgement

Type of funding sources: None. Predictors of the presence of LVRChanges (Δ%) of LVEDV and LVESV

Post-procedural high platelet reactivity with prasugrel loading predicts in-hospital adverse events in ACS patients

Background/Introduction

High platelet reactivity (HPR) is associated with adverse cardiovascular events, primarily intrastent thrombosis, after a percutaneous coronary intervention (PCI). However, the relationship between hyperacute postprocedural HPR with prasugrel loading and clinical outcomes in acute coronary syndrome (ACS) remains unclear. Moreover, factors contributing to HPR in ACS with prasugrel loading are also unknown.

Purpose

To assess the effects of post-procedural HPR with prasugrel loading on clinical outcomes in ACS during hospitalization, and to define the appropriate cut-off values and identify factors contributing to HPR.

Methods

A single-center, retrospective observational study that enrolled 154 patients who underwent emergent PCI for ACS with prasugrel loading was performed. The P2Y12 reaction unit (PRU) value was measured immediately after PCI using the VerifyNowR system. The primary end-point was major adverse cardiac events (MACE, defined as the composite of death, myocardial infarction, stroke, heart failure, ventricular arrhythmia needing defibrillation).

Results

The mean patient age (standard deviation) was 70.7 (±12.5) years, 76.6% were men, and the average time from the prasugrel intake to PRU calculation was 103.2 (±48.5) min. During the mean hospital stay of 15.6 (±8.5) days, 24 in-hospital MACE (15.5%) and 8 deaths (5.2%) occurred. Thrombosis events, including myocardial infarction recurrence, did not occur (only one case of spontaneous coronary artery dissection was considered as myocardial infarction recurrence). PRU was significantly higher in the MACE group than that in Non-MACE group (287±55 and 232±64, respectively, p<0.001). The ROC curve analysis of PRU for discriminating the significant in-hospital MACE showed the cut-off value of 293 (sensitivity: 62.5%, specificity: 83.1% [AUC=0.756, p<0.0001]). A total of 37 patients (24%) were thus categorized as HPR (PRU>293) immediately after the emergent PCI. Kaplan-Meier curve showing MACE events occurred in the HPR group than that in the non-HPR group (40.5% vs 7.6%, p<0.001). Multiple cox analysis demonstrated that HPR was independent predictors of MACE in patients with ACS who underwent PCI (OR 11.01, 95% CI 2.39–20.2, p<0.0001). Multiple logistic regression model showed old age, female sex, low systolic blood pressure, short prasugrel intake to measure time, and large acute gain were independent predictors of HPR.

Conclusion

PRU was significantly higher in the MACE group, with an appropriate cut-off value of HPR of 293 in this study. HPR was an independent predictor of MACE during hospitalization; however, thrombosis events were not significant. HPR predictors were old age, female sex, low systolic blood pressure, short prasugrel intake to measure time, and large acute gain. This study shows the post-procedural HPR with prasugrel loading in patients with ACS can be a useful predictive marker of adverse events during hospitalization.

Funding Acknowledgement

Type of funding source: None

Cardio-ankle vascular index as an arterial stiffness marker improves on cardiovascular events by adding to framingham risk score

Background

The cardio-ankle vascular index (CAVI) is a non-invasive measurement that evaluates arterial stiffness using the analysis of oscillometric waveform during cuff-Inflation. Several studies reported that CAVI is associated with cardiovascular risk factors, while the clinical prognostic value of CAVI as a surrogate marker of atherosclerosis has not been fully elucidated. Meanwhile, the Framingham risk score (FRS) is an established marker of cardiovascular outcomes.

Purpose

To investigate whether adding CAVI to Framingham risk score improves the prediction of cardiovascular events.

Methods

This prospective observational study included consecutive 422 patients with cardiovascular risk factors but without known coronary artery disease (69±8 years, 63% men). CAVI was measured by the oscillometric method with VaSera vascular screening system. Patients with atrial fibrillation, left ventricular ejection fraction <50%, both ABI<0.9, severe valvular diseases, or hemodialysis were excluded. Primacy outcomes were cardiovascular death, myocardial infarction, stroke, hospitalization for heart failure and revascularization.

Results

During a median follow-up of 3.1 years, cardiovascular events occurred in 12.8% (3.3%, 15.7%, and 19.1% in the low, intermediate and high-risk group of stratification by FRS, respectively). The ROC curve analysis for discriminating cardiovascular events showed that the AUC of CAVI added to Framingham risk score was the highest compared to Framingham risk score and CAVI alone (CAVI added to Framingham risk score: AUC 66.9, 95% CI 59.6–74.2, Framingham risk score alone: AUC 61.5, 95% CI 53.8–69.1, CAVI alone: AUC 62.3, 95% CI 54.1–70.6). The logistic regression analysis demonstrated that CAVI and Framingham risk score were independent predictors of cardiovascular events (CAVI: OR 1.381, 95% CI 1.164–1.597, p=0.004, Framingham risk score: OR 1.135, 95% CI 1.044–1.225, p=0.007). Next, when logistic regression analysis was performed simultaneously on Framingham risk factor and CAVI, CAVI was an independent predictor of cardiovascular events (OR 1.347, 95% CI 1.124–1.569, p=0.009). Furthermore, in the likelihood ratio test, CAVI added to Framingham risk score significantly improved the cardiovascular event prediction ability than Framingham risk factor alone. Next, when patients with intermediate risk (n=217) were divided into two groups based on CAVI of 9.0, the Kaplan-Meier estimate showed that events occurred more frequently in higher CAVI group (9.3% and 29.1%, log-rank, P=0.009) and the C-statistic was 0.662. Multiple Cox analysis showed that, in the intermediate risk group, CAVI was an independent predictor of primary outcomes (HR 1.387 per 1 index, 95% CI 1.081–1.779, p=0.010).

Conclusion

The measurement of CAVI could be a useful predictor for cardiovascular events. In addition, the combination of CAVI and Framingham risk score could improve the predictability compared to the Framingham risk score alone.

Funding Acknowledgement

Type of funding source: None

Development of assembled microchannel resonator as an alternative fabrication method of a microchannel resonator for mass sensing in flowing liquid

We propose an alternate fabrication technique of microchannel resonators based on an assembly method of three separate parts to form a microchannel resonator on a chip. The capability of the assembled microchannel resonator to detect mass is confirmed by injecting two liquids with different densities. The experimental and theoretical values of the resonator frequency shift are in agreement with each other, which confirms the consistency of the device. The noise level of the device is estimated from the Allan variance plot, so the minimum detectable mass of 230 fg after 16 s of operation is expected. By considering the time of the practical application of 1 ms, it is found that a detectable mass of around 8.51 pg is estimated, which is applicable for detecting flowing microparticles. The sub-pico to a few picogram levels of detection will be applicable for the mass analysis of flowing microparticles such as single cells and will be greatly beneficial for many fields such as chemistry, medicine, biology, and single-cell analysis.

0757 Increasing Number of Cases Who Had Both Hypersomnolence Disorders and Developmental Disorders With Orexin Measurements

Introduction

Recently, attention has been paid to the relationship between developmental disorders such as attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), and sleep disorders. We meet many developmental disorder patients who complaint hypersomnolence. Among these patients, cases with coexistence of central hypersomnia and developmental disorders, or developmental disorder alone were increased. Therefore, we first investigated patients with the complaint of hypersomnolence, who were also suspected developmental disorders. Furthermore, we have been measuring CSF orexin in 17 cases suspected of both disorders to investigate orexin levels of these patients.

Methods

86patients who complained of EDS with suspicion of developmental disorders had been examined. In order to diagnose hypersomnolence disorders, PSG and MSLT were performed. Psychological examinations were performed for diagnosing developmental disorders.We have been measuring for CSF orexin in 17 cases suspected both hypersomnolence and developmental disorders. We examined the onset of hypersomnolence and the clinical history of these ADHD or ASD cases for more details.

Results

In 86 examined cases, developmental disorders coexisted in 30 cases. Among 30 cases, ADHD were 18, ASD were 6 and both diagnosed were 6 cases. Among them, 20 cases diagnosed as having coexistence of hypersomnia (8: narcolepsy, 12: IHS) and developmental disorders (ADHD:12, ASD:4, ADHD/ASD:4). In 17 cases with orexin measurements, 10 cases coexisted ADHD and 4 cases coexisted ASD. Two cases diagnosed as both ADHD and ASD. In 10 ADHD cases, 3 cases had low orexin levels, and 7 cases had normal orexin levels. Other 7 ASD cases had normal orexin levels.

Conclusion

ADHD has a higher rate of central hypersomnia (12/18) compared with ASD and the rate of narcolepsy was also high (5/12). While patients in ASD was diagnosed as IHS (3/6), narcolepsy cases were not observed. It became clear that the majority of patients had developmental disorder or had a tendency for developmental disorder before the onset of hypersomnolence.Although it is possible that ADHD/ASD symptoms may be exacerbated by orexin dysfunctions, ADHD/ASD may not newly occur. There were cases with low orexin levels, but it seems that narcolepsy happened to coexist with developmental disorders.

Support

a

P4634Acute-phase high platelet reactivity with prasugrel loading is correlated with clinical outcomes during hospitalization in acute coronary syndrome

Background/Introduction

Although high platelet reactivity (HPR) seems to be associated with adverse cardiovascular events after percutaneous coronary intervention (PCI), the relationship between post-procedure HPR with prasugrel loading and clinical outcomes in acute coronary syndrome (ACS) is still unclear. Moreover, factors contributing to HPR in ACS with prasugrel loading are also unknown.

Purpose

This study aimed to assess the impact of post-procedure HPR with prasugrel loading on clinical outcomes in ACS during hospitalization, as well as to define appropriate cut-off values and identify factors contributing to HPR.

Methods

We performed a single-centre, retrospective observational study that enrolled 132 patients who underwent emergent PCI for ACS with prasugrel loading. The P2Y12 reaction unit (PRU) value was measured immediately after PCI with the VerifyNowR System. The primary endpoint was major adverse cardiac events (MACE, defined as the composite of death, myocardial infarction, stroke, heart failure, ventricular arrhythmia needing defibrillation).

Results

Mean patient age (standard deviation) was 70.7 (±12.5) years, 76% were male, and average time from prasugrel intake to PRU calculation was 101 (±48.8) min. During a mean hospital stay of 15.4 (±8.0) days, there were 22 (16%) MACE events and 6 (4%) deaths. The post-procedure PRU value was 241±66. HPR was significantly higher in MACE group than non-MACE group [287 (±55) vs 232 (±64), p<0.001]. The ROC curve analysis of PRU for discriminating significant in-hospital MACE showed a cut off value of 293 (sensitivity: 64%, specificity: 84% [AUC=0.764, p<0.0001]). Thus, 33 patients (25%) were found to have HPR (PRU>293) immediately after emergent PCI. Kaplan-Meier curve analysis showed MACE events occurred more frequently in the HPR group than in the non-HPR group (42% vs 8%, log rank p<0.001). Multiple Cox regression analysis showed that peak creatine phosphokinase >3,000 U/L and HPR were independent predictors of MACE in patients with ACS who underwent PCI (OR 4.96, 95% CI 1.86–13.26, p=0.001, and OR 7.52, 95% CI 2.73–20.7, p<0.0001, respectively). HPR was significantly correlated with age, female sex, and reference lumen short diameter (pre-dilation) used in PCI.

Conclusion

HPR was significantly associated with adverse event during hospitalization in ACS patients. Female patients with large culprit lesion diameter were more likely to have HPR. Appropriate cut-off value of HPR in this study was 293. HPR in early-phase of ACS with prasugrel loading is a useful predictor of adverse events during hospitalization.

Fungal Planet description sheets: 868-950

Novel species of fungi described in this study include those from various countries as follows: Australia, Chaetomella pseudocircinoseta and Coniella pseudodiospyri on Eucalyptus microcorys leaves, Cladophialophora eucalypti, Teratosphaeria dunnii and Vermiculariopsiella dunnii on Eucalyptus dunnii leaves, Cylindrium grande and Hypsotheca eucalyptorum on Eucalyptus grandis leaves, Elsinoe salignae on Eucalyptus saligna leaves, Marasmius lebeliae on litter of regenerating subtropical rainforest, Phialoseptomonium eucalypti (incl. Phialoseptomonium gen. nov.) on Eucalyptus grandis × camaldulensis leaves, Phlogicylindrium pawpawense on Eucalyptus tereticornis leaves, Phyllosticta longicauda as an endophyte from healthy Eustrephus latifolius leaves, Pseudosydowia eucalyptorum on Eucalyptus sp. leaves, Saitozyma wallum on Banksia aemula leaves, Teratosphaeria henryi on Corymbia henryi leaves. Brazil, Aspergillus bezerrae, Backusella azygospora, Mariannaea terricola and Talaromyces pernambucoensis from soil, Calonectria matogrossensis on Eucalyptus urophylla leaves, Calvatia brasiliensis on soil, Carcinomyces nordestinensis on Bromelia antiacantha leaves, Dendryphiella stromaticola on small branches of an unidentified plant, Nigrospora brasiliensis on Nopalea cochenillifera leaves, Penicillium alagoense as a leaf endophyte on a Miconia sp., Podosordaria nigrobrunnea on dung, Spegazzinia bromeliacearum as a leaf endophyte on Tilandsia catimbauensis, Xylobolus brasiliensis on decaying wood. Bulgaria, Kazachstania molopis from the gut of the beetle Molops piceus. Croatia, Mollisia endocrystallina from a fallen decorticated Picea abies tree trunk. Ecuador, Hygrocybe rodomaculata on soil. Hungary, Alfoldia vorosii (incl. Alfoldia gen. nov.) from Juniperus communis roots, Kiskunsagia ubrizsyi (incl. Kiskunsagia gen. nov.) from Fumana procumbens roots. India, Aureobasidium tremulum as laboratory contaminant, Leucosporidium himalayensis and Naganishia indica from windblown dust on glaciers. Italy, Neodevriesia cycadicola on Cycas sp. leaves, Pseudocercospora pseudomyrticola on Myrtus communis leaves, Ramularia pistaciae on Pistacia lentiscus leaves, Neognomoniopsis quercina (incl. Neognomoniopsis gen. nov.) on Quercus ilex leaves. Japan, Diaporthe fructicola on Passiflora edulis × P. edulis f. flavicarpa fruit, Entoloma nipponicum on leaf litter in a mixed Cryptomeria japonica and Acer spp. forest. Macedonia, Astraeus macedonicus on soil. Malaysia, Fusicladium eucalyptigenum on Eucalyptus sp. twigs, Neoacrodontiella eucalypti (incl. Neoacrodontiella gen. nov.) on Eucalyptus urophylla leaves. Mozambique, Meliola gorongosensis on dead Philenoptera violacea leaflets. Nepal, Coniochaeta dendrobiicola from Dendriobium lognicornu roots. New Zealand, Neodevriesia sexualis and Thozetella neonivea on Archontophoenix cunninghamiana leaves. Norway, Calophoma sandfjordenica from a piece of board on a rocky shoreline, Clavaria parvispora on soil, Didymella finnmarkica from a piece of Pinus sylvestris driftwood. Poland, Sugiyamaella trypani from soil. Portugal, Colletotrichum feijoicola from Acca sellowiana. Russia, Crepidotus tobolensis on Populus tremula debris, Entoloma ekaterinae, Entoloma erhardii and Suillus gastroflavus on soil, Nakazawaea ambrosiae from the galleries of Ips typographus under the bark of Picea abies. Slovenia, Pluteus ludwigii on twigs of broadleaved trees. South Africa, Anungitiomyces stellenboschiensis (incl. Anungitiomyces gen. nov.) and Niesslia stellenboschiana on Eucalyptus sp. leaves, Beltraniella pseudoportoricensis on Podocarpus falcatus leaf litter, Corynespora encephalarti on Encephalartos sp. leaves, Cytospora pavettae on Pavetta revoluta leaves, Helminthosporium erythrinicola on Erythrina humeana leaves, Helminthosporium syzygii on a Syzygium sp. bark canker, Libertasomyces aloeticus on Aloe sp. leaves, Penicillium lunae from Musa sp. fruit, Phyllosticta lauridiae on Lauridia tetragona leaves, Pseudotruncatella bolusanthi (incl. Pseudotruncatellaceae fam. nov.) and Dactylella bolusanthi on Bolusanthus speciosus leaves. Spain, Apenidiella foetida on submerged plant debris, Inocybe grammatoides on Quercus ilex subsp. ilex forest humus, Ossicaulis salomii on soil, Phialemonium guarroi from soil. Thailand, Pantospora chromolaenae on Chromolaena odorata leaves. Ukraine, Cadophora helianthi from Helianthus annuus stems. USA, Boletus pseudopinophilus on soil under slash pine, Botryotrichum foricae, Penicillium americanum and Penicillium minnesotense from air. Vietnam, Lycoperdon vietnamense on soil. Morphological and culture characteristics are supported by DNA barcodes.

Doublon-holon pairing mechanism via exchange interaction in two-dimensional cuprate Mott insulators

Coupling of charge and spin degrees of freedom is a critical feature of correlated electron oxides, as represented by the spin-related mechanism of a Cooper pair under high-T _c superconductivity. A doublon-holon pair generated on an antiferromagnetic spin background is also predicted to attract each other via the spin-spin interaction J, similar to a Cooper pair, while its evidence is difficult to obtain experimentally. Here, we investigate such an excitonic effect by electroreflectance spectroscopy using terahertz electric field pulses in undoped cuprates: Nd₂CuO₄, Sr₂CuO₂Cl₂, and La₂CuO₄. Analyses of the spectral changes of reflectivity under electric fields reveal that the splitting of odd-parity and even-parity excitons, a measure of doublon-holon binding energy, increases with J. This trend is reproduced by t-J-type model calculations, providing strong evidence of the spin-related doublon-holon pairing. Agreement with the calculations supports the s-wave symmetry of the doublon-holon pair in contrast to the d-wave Cooper pair in doped cuprates.

Pressure-tuning the quantum spin Hamiltonian of the triangular lattice antiferromagnet Cs2CuCl4

Quantum triangular-lattice antiferromagnets are important prototype systems to investigate numerous phenomena of the geometrical frustration in condensed matter. Apart from highly unusual magnetic properties, they possess a rich phase diagram (ranging from an unfrustrated square lattice to a quantum spin liquid), yet to be confirmed experimentally. One major obstacle in this area of research is the lack of materials with appropriate (ideally tuned) magnetic parameters. Using Cs₂CuCl₄ as a model system, we demonstrate an alternative approach, where, instead of the chemical composition, the spin Hamiltonian is altered by hydrostatic pressure. The approach combines high-pressure electron spin resonance and r.f. susceptibility measurements, allowing us not only to quasi-continuously tune the exchange parameters, but also to accurately monitor them. Our experiments indicate a substantial increase of the exchange coupling ratio from 0.3 to 0.42 at a pressure of 1.8 GPa, revealing a number of emergent field-induced phases.

Theoretical studies of quantum magnetism typically assume idealised lattices with freely tunable parameters, which are difficult to realise experimentally. Zvyagin et al. perform challenging measurements at high pressures to tune and to accurately monitor the exchange parameters of a triangular lattice antiferromagnet.

Microwave oscillator using piezoelectric thin-film resonator aiming for ultraminiaturization of atomic clock

We developed a microwave oscillator and a micro electromechanical systems-based rubidium cell for the miniaturization of atomic clocks. A thin-film bulk acoustic resonator (FBAR) having a resonant frequency of the fundamental mode in the 3.5 GHz band was employed instead of a crystal resonator. It delivers a clock transition frequency of Rb atoms of 3.417 GHz without the need for a complicated frequency multiplication using a phase-locked loop. This topology considerably reduces the system scale and power consumption. For downsizing the atomic clock system toward the chip level as well as mass production, a microfabricated gas cell containing Rb and N₂ gases was also developed. These microcomponents were incorporated into an atomic clock test bench, resulting in a clock operation with a short-term frequency instability of 2.1 × 10^-11 at 1 s. To the best of our knowledge, this is the first report of a coherent population trapping clock operation using an FBAR-based microwave oscillator as well as a microfabricated gas cell.

Flexible and wavelength-independent optical transmission for laser pointing stabilization and assembly error compensation

A flexible light guide was developed for an ITER (International Thermonuclear Experimental Reactor) poloidal polarimeter which is a passive laser beam alignment and stabilization system for free-space propagation of a wide range of wavelengths. The advantages of using a flexible light guide are (1) to compensate the relative movement between the floor of a building and an optical table, (2) to negate assembly error of the optical transmission line, (3) to minimize the time required for assembly of the line and laser position alignment in a radiological environment, and (4) to transmit a wide wavelength range from visible to far-infrared. The authors fabricated a flexible light guide with an inner diameter of 120 mm and with a motion range of 10 cm. Pointing stability of the laser beam passing through the flexible light guide was less than 70 μrad when the support moved ±50 mm. A flexible light guide error of 70 μrad leads to a beam position displacement of 0.98 mm at a beam position steering mirror ITER poloidal polarimeter that is located 14 m from the flexible light guide. The achieved error is stable enough to guide the laser beam to its target in ITER.

Observation of a Goos-Hänchen-like Phase Shift for Magnetostatic Spin Waves

In optics, a light beam experiences a spatial shift in the beam plane upon total internal reflection. This shift is usually referred to as the Goos-Hänchen shift. When dealing with plane waves, it manifests itself as a phase shift between an incoming and reflected wave that depends on the wave vector component along the interface. In the experiments presented here, plane spin waves are excited in a 60-nm-thick Permalloy film and propagate towards the edge of the film. By means of time-resolved scanning Kerr microscopy, we are able to directly detect a phase shift between the incoming and reflected wave. With the help of a numerical model, we show that this phase shift naturally occurs for spin waves in the dipolar regime.

Pre-treatment CD8+ tumour-infiltrating lymphocyte density predicts distant metastasis after definitive treatment in patients with stage III/IV hypopharyngeal squamous cell carcinoma

OBJECTIVES

Although inflammatory markers, such as the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and local immune markers have been shown to have prognostic utility, limited information is available regarding inflammatory and pre-existing tumour-infiltrating lymphocyte density and their association with prognosis in patients with hypopharyngeal squamous cell carcinoma. We investigated the prognostic ability of inflammatory markers and tumour-infiltrating lymphocyte density in stage III and stage IV hypopharyngeal squamous cell carcinoma patients receiving definitive treatment.

DESIGN

Retrospective cohort study.

SETTING

Kurume University Hospital.

PARTICIPANTS

Ninety-six stage III or stage IV hypopharyngeal squamous cell carcinoma patients treated at the Kurume University Hospital between 2000 and 2014.

MAIN OUTCOME MEASURES

Inflammatory markers and pre-treatment tumour-infiltrating lymphocyte density were examined from recorded haematologic data and immunohistochemical analysis.

RESULTS

Multivariate analyses showed that the CD8⁺ tumour-infiltrating lymphocyte density was an independent predictive factor for distant metastasis and overall survival, whereas inflammatory markers, including the neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio, were not correlated with distant metastasis or overall survival.

CONCLUSIONS

Higher pre-treatment CD8⁺ tumour-infiltrating lymphocyte density is a useful predictive biomarker for reduced distant metastasis and better prognosis.

Resolving the Lophiostoma bipolare complex: Generic delimitations within Lophiostomataceae

Lophiostoma bipolare was taxonomically revised based on the morphological observations and phylogenetic analyses of molecular data from nuclear rDNA SSU-ITS-LSU, TUB, tef1, and rpb2 genes. Twenty-nine strains were morphologically similar to Lo. bipolare. A total of 174 sequences were generated from the Lo. bipolare complex. Phylogenetic analyses based on TUB sequence revealed 11 distinct species within the Lo. bipolare complex. Morphological features of the ascospores and the anatomical structure of the ascomata from both field collections as well as axenic culture, which have been reported previously as variable features at intraspecific levels, were compared to evaluate the taxonomic reliability of these features. To clarify the generic position of the 11 species, phylogenetic analyses were done on SSU-ITS-LSU-tef1-rpb2 gene sequences. The Lo. bipolare complex shared phylogenetic relationships with Pseudolophiostoma and Vaginatispora, and formed an additional five distinct clades from other members of Lophiostomataceae. According to its phylogenetic position, Lo. bipolare sensu stricto was distantly related to Lophiostoma s. str., and formed an independent clade within Lophiostomataceae. Lophiostoma bipolare s. str. could be distinguished from the other lophiostomataceous genera by the clypeus around the ostiolar neck and by the thin and uniformly thick peridium. A novel genus described as Lentistoma was established to accommodate this species, and the epitypification of Lentistoma bipolare (basionym: Massarina bipolaris) was proposed. Other lineages of the Lo. bipolare complex could not be separated on the basis of the ascospore size and sheath variations, but were distinguished based on ascomatal features, such as the existence of the clypeus, brown hyphae surrounding the peridium, and the contexture of the peridium, which were stable indicators of generic boundaries in Lophiostomataceae. Four additional new genera with five new species were recognised based on these morphological differences: Crassiclypeus (C. aquaticus), Flabellascoma (F. cycadicola and F. minimum), Leptoparies (Lep. palmarum), and Pseudopaucispora (Pseudop. brunneospora). Three new species were added to Pseudolophiostoma (Pseudol. cornisporum, Pseudol. obtusisporum, and Pseudol. tropicum) and two new species were added to Vaginatispora (V. amygdali and V. scabrispora). The re-evaluation of the validity of several previously recognised genera resulted in the introduction of two new genera with new combinations for Lophiostoma pseudoarmatisporum as Parapaucispora pseudoarmatispora and Vaginatispora fuckelii as Neovaginatispora fuckelii.

Enhanced immunity in intradermal vaccination by novel hollow microneedles

BACKGROUND

The intradermal (ID) route for vaccination represents an effective alternative to subcutaneous (SC)/intramuscular administration to induce protective immunity. However, a critical issue associated with ID vaccination is the precise delivery of solution in the upper dermis, which ensures enhanced immunity.

METHODS

We fabricated a hollow microneedle unit made of poly-glycolic acid by injection molding and bonding, and created a dedicated prototype injector. To ensure ID delivery of solution, the injected site was macroscopically and microscopically examined. Serum immunoglobulin G antibody production was measured by enzyme immunoassay and compared in groups of rats following either ID delivery with microneedles or SC administration with a 27-G stainless needle of graded vaccine doses.

RESULTS

The unit used a tandem array of six microneedles, each with a side delivery hole, and a conduit inside for solution. Microneedles installed in the injector punctured the skin with the aid of a spring. Injection of solution formed a wheal due to ID distribution. Histologically, a wedge-shaped skin defect in the upper skin corresponded to each puncture site. Antibody titers following vaccinations on days 1 and 8 were significantly higher with ID injection than with SC delivery on day 15 and every 7 days thereafter until day 36 with mumps vaccination, and until day 36 with varicella vaccination.

CONCLUSIONS

The microneedle unit presented here delivered solution intradermally without any difficulty and evoked antibody responses against viruses even with the reduced vaccine volume. Our findings confirm promising results of ID delivery as an immunogenic option to enhance vaccination efficacy.

Microscopic Investigation into the Electric Field Effect on Proximity-Induced Magnetism in Pt

Electric field effects on magnetism in metals have attracted widespread attention, but the microscopic mechanism is still controversial. We experimentally show the relevancy between the electric field effect on magnetism and on the electronic structure in Pt in a ferromagnetic state using element-specific measurements: x-ray magnetic circular dichroism (XMCD) and x-ray absorption spectroscopy (XAS). Electric fields are applied to the surface of ultrathin metallic Pt, in which a magnetic moment is induced by the ferromagnetic proximity effect resulting from a Co underlayer. XMCD and XAS measurements performed under the application of electric fields reveal that both the spin and orbital magnetic moments of Pt atoms are electrically modulated, which can be explained not only by the electric-field-induced shift of the Fermi level but also by the change in the orbital hybridizations.

The Immunological Impact of Chemotherapy on the Tumor Microenvironment of Oral Squamous Cell Carcinoma

　Anticancer drugs induce cell-cycle arrest and apoptosis not only in tumor cells, but also in immune cells. However, many preclinical and clinical findings show that some chemotherapeutic agents can improve the antitumor efficacy of immunotherapy. We immunohistochemically analyzed the degree of immune cell infiltration and the relevance of programmed cell death 1 ligand-1 (PD-L1) expression in surgically resected oral squamous cell carcinoma (OSCC) specimens from patients who had undergone pretreatment with certain chemotherapies and other patients without pretreatment. We divided the patients into the group of neoadjuvant chemotherapy (NAC) patients (n=8) and the nNAC (without NAC) patient group (n=10). We observed that NAC induced infiltrations of CD4, CD8 T cells and CD56 NK cells into the tumor microenvironment. Decreased numbers of Tregs and PD-1-positive cells were observed in the NAC group. No significant difference was observed in the degree of immune-cell infiltration between the patient groups except for CD56 NK cells in the stroma and PD-1 cells in cancer nests. Eighty percent of the nNAC specimens showed intermediate-to-strong PD-L1 protein expression, whereas 75% of the NAC specimens showed down-regulation of the PD-L1 protein, indicating the effectiveness of the chemotherapeutic treatment before surgery.

Development of Co-Culture System of Hepatocytes with Bone Marrow Cells for Expression and Maintenance of Hepatic Functions

In this study, a co-culture system of hepatocytes and bone marrow cells (BMCs) was developed and characterized for the expression and maintenance of ammonia metabolism and albumin secretion activities. A culture medium supplemented with epidermal growth factor, insulin, L-proline, hydrocortisone and 20 % (v/v) heat-inactivated fetal bovine serum was developed. In addition to adhesive bone marrow cells, the co-existence of non-adhesive bone marrow cells was effective in expressing liver-specific functions for at least 3 weeks. On the other hand, experiments with Transwell in which cultured cells were separated by a semi-permeable membrane, suggested that soluble factors secreted by BMCs are the key components in the functional enhancement of cells. Furthermore, direct contact between hepatocytes and BMCs enhanced the formation of spheroids and the expression of liver specific functions. These results indicate that this co-culture system is promising in, for example, bioartificial liver, regenerative medicine, and liver function simulator applications.

Digoxin Transport by Renal Proximal Tubule Cells is Enhanced by Adhesive Synthetic RGD Peptide

Introduction

The dialyzer apparatus has been widely used as an artificial kidney in medical treatment. However, side effects such as amyloidosis have occurred during long-term treatment. Therefore, we focused on developing a hybrid artificial kidney with a filtration and reabsorption apparatus, but it was found that cells spread extensively and it is difficult to maintain a uniform monolayer with a regular cell shape on a collagen-coated substrate. The purpose of this study was to improve cell adhesion, uniform stable monolayer formation and active transport function by immobilization of arginine-glycine-aspartic acid (RGD) on the culture substratum.

Materials and Methods

Polycarbonate semipermeable membranes were coated with collagen, fibronectin, laminin and synthetic polypeptide, including RGD (Pronectin F). Cell adhesion and digoxin transport were estimated using a renal proximal tubule cell line that overexpressed the P-glycoprotein gene.

Results and Discussion

Under initial and confluent conditions, immobilized cell density in Pronectin F-coated wells was higher than that under other conditions. Transepithelial electrical resistance and digoxin transport activity on Pronectin F-coated membranes were the highest of all conditions. This might have been caused by uniform cell morphology and high cell density.

Combined effects of electric toothbrushing and dentifrice on artificial stain removal: An in vitro study

Background

This in vitro study aimed to clarify the combined effect of electric toothbrushing and dentifrice on the removal of artificial stain.

Material and Methods

Twenty-five bovine incisors were cut at the cervix and the crown was embedded in auto-cured acrylic resin. Specimens were abraded using #240 SiC paper to obtain a flat enamel surface, and 20 specimens were treated with 10% citric acid / 3% ferric chloride solution followed by 1% tannic acid solution to produce surface staining. They were divided into four groups: 1) brushing with an electric toothbrush and whitening dentifrice (group S+B); 2) brushing with an electric toothbrush and fluoride dentifrice (group S+C); 3) brushing with an electric toothbrush and no dentifrice (group S); and 4) no brushing (control group). The remaining five specimens were used as a baseline. Color values (L*, a*, and b* were measured before brushing (0 min), and at 1 min, 5 min, 10 min, and 20 min using a microscopic area spectrophotometer. The color change (ΔE) was calculated by subtracting the baseline values from the final color values obtained at each time point. The data were statistically analyzed using two-way repeated-measures analysis of variance and Tukey’s honest significant difference test as a post hoc test (p<0.05).

Results

The L* values of groups S+B and S+C increased over time (p<0.05), but no significant differences were observed in group S and the control group at any of the time points (p>0.05). Groups S+B and S+C demonstrated greater ΔE values than group S.

Conclusions

The combination of electric toothbrushing and dentifrice removed the artificial stain more effectively than brushing without dentifrice. However, the stain removal was limited. The two dentifrices evaluated in this study exhibited similar stain removal effects.

Key words:Color change, stain removal, dentifrice, electric toothbrush, whitening effect.