Impact of right ventricular reserve on exercise capacity and quality of life in patients with left ventricular assist device

Background

Right heart failure following left ventricular assist device (LVAD) implantation is a major complication which significantly impairs functional capacity and quality of life (QoL). Right ventricular (RV) reserve function may limit exercise capacity and QoL in LVAD patients; however, most patients show normal RV haemodynamics at rest.

Purpose

The aim of this study was to investigate whether RV reserve assessed by the changes of RV function during exercise is correlated with exercise capacity and QoL in patients with LVAD.

Methods

We prospectively examined 20 consecutive LVAD patients who were admitted to our university hospital between June 2020 and November 2021 after excluding those who were unable to perform exercise (n=8). All patients underwent invasive exercise right heart catheterisation with simultaneous echocardiography in the supine position. RV stroke work index (RVSWI) was calculated as 0.0136 × stroke volume index × (mean pulmonary artery pressure [mPAP] − right atrial pressure [RAP]) at rest and during exercise. Exercise capacity and QoL were assessed by 6-minute walk distance (6MWD) and peak oxygen consumption (VO2) in cardiopulmonary exercise testing, and the EuroQol visual analogue scale (EQ-VAS), respectively. The patients were divided into two groups according to the median ΔRVSWI (RVSWI change from rest to peak exercise) of 1.45 (interquartile range [IQR] −0.31 to 8.25) g/m2.

Results

Patients were predominantly male (75%) and the median age was 47 (IQR 38–60) years. Patients with lower ΔRVSWI had significantly higher change on RAP (P=0.019), but significantly lower change on mPAP (P<0.001) compared to those with higher ΔRVSWI. There were no significant differences in age, gender, primary aetiology of heart failure, type of LVAD devices, or echocardiographic parameters including tricuspid annular plane systolic excursion, and RVSWI at rest between the groups. ΔRVSWI during exercise were positively correlated with 6MWD (R=0.69, P<0.01) and peak VO2 (R=0.66, P<0.01) (Figure A). In addition, ΔRVSWI during exercise were positively correlated with the EQ-VAS (R=0.48, P=0.031). On the other hand, there was no significant correlation between RVSWI at rest and 6MWD (R=−0.11, P=0.63) and peak VO2 (R=0.13, P=0.95), and the EQ-VAS (R=0.11, P=0.61). During a median follow-up period of 312 (IQR 176–369) days, adverse events occurred in 3 patients (15%), including 1 death and 2 hospitalisations for major bleeding and right heart failure. Kaplan-Meier analysis revealed that the adverse events more frequently occurred in patients with lower ΔRVSWI compared to those with higher ΔRVSWI (Figure B).

Conclusions

ΔRVSWI was positively correlated with 6MWD, peak VO2 and EQ-VAS irrespective of RV function at rest. Our findings suggest that the assessment of RV reserve function using ΔRVSWI would be useful for risk stratification in patients with LVAD.

Funding Acknowledgement

Type of funding sources: None.

Validation of the HFA-PEFF and the H2FPEF scores for the diagnosis of heart failure with preserved ejection fraction in Japanese patients:a report from the Japanese multicentre registry

Background

The standard diagnosis of heart failure (HF) with preserved ejection fraction (HFpEF) is based on the following: 1) symptoms of HF, 2) preserved left ventricular (LV) ejection fraction (LVEF, >50%), and 3) presence of LV diastolic dysfunction confirmed by echocardiography or cardiac catheterisation. However, there are limits to the diagnostic accuracy of individual parameters, and what cut-off values should be applied and how they should be combined remain unclear. Diagnostic algorithms for HFpEF such as the HFA-PEFF algorithm and the H2FPEF score have been proposed; however, previous validation studies were conducted in stable chronic HF and did not include an invasive haemodynamic assessment. Thus, the diagnostic accuracy for HFpEF lacked robustness. Moreover, information on their applicability in the Asian population is limited.

Purpose

The aim of this study was to investigate these scores' diagnostic validity for HFpEF in Japanese patients recently hospitalised due to acute decompensated HF.

Methods

We examined patients with HFpEF recently hospitalised with acute decompensated HF whose HFA-PEFF and H2FPEF scores could be calculated at discharge from a nationwide HFpEF-specific multicentre registry (HFpEF group) and control patients who underwent echocardiography to investigate the cause of dyspnoea in our hospital (Non-HFpEF group). We calculated the HFA-PEFF and the H2FPEF scores among the studied population. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were computed to compare the diagnostic accuracy of these scores.

Results

The studied population included 372 consecutive patients (194 HFpEF group and 178 Non-HFpEF group; HFpEF prevalence, 52%). The HFA-PEFF score classified 155 (42%) of all patients into the high likelihood category (5–6 points) and only 19 (5%) into the low likelihood category (0–1 point). A high HFA-PEFF score could diagnose HFpEF with a high specificity of 84% and a positive predictive value (PPV) of 82%, and a low HFA-PEFF score could rule out HFpEF with a high sensitivity of 99% and a negative predictive value (NPV) of 89%. The H2FPEF score classified 86 (23%) of all patients into the high likelihood category (6–9 points) and 84 (23%) into the low likelihood category (0–1 point). HFpEF could be diagnosed with a high H2FPEF score (specificity, 97%; PPV, 94%) or ruled out with a low H2FPEF score (sensitivity, 97%; NPV, 93%). The diagnostic accuracy for the HFA-PEFF and H2FPEF scores was 0.82 (95% confidence interval [CI] 0.78–0.86) and 0.89 (95% CI 0.86–0.93), respectively, by the AUC of the ROC curve (P=0.004) (Figure 1A). In the HFA-PEFF sub-scores, the functional score showed little diagnostic value, while the morphological and biomarker scores showed moderate diagnostic value (Figure 1B).

Conclusions

The H2FPEF score may be more useful than the HFA-PEFF score in diagnosing HFpEF in Japanese patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS KAKENHI) Figure 1

Applicability of the AHA/ACC/HRS guideline for implantable cardioverter defibrillator implantation in Japanese patients with cardiac sarcoidosis

Background

Sarcoidosis is a systemic granulomatous disease that affects multiple organs. Cardiac involvement is a key determinant of poor clinical outcomes in the patients with sarcoidosis, as it causes congestive heart failure, conduction abnormalities, ventricular tachycardia and fibrillation (VT/VF), and sudden cardiac death (SCD). Although implantable cardioverter defibrillators (ICDs) are used to prevent SCD from VT/VF in patients with cardiac sarcoidosis (CS), the generalizability of the AHA/ACC/HRS guidelines for the Japanese CS patients remains unclear.

Purpose

We aimed to assess, among Japanese patients with CS, the ICD recommendations from the 2017 AHA/ACC/HRS Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death.

Methods

We examined 188 consecutive patients with CS in two tertiary hospitals between 1979 and 2020. The primary outcome was defined as a composite outcome involving SCD or ventricular arrhythmic events. Ventricular arrhythmic events were defined as either emergency treatment for VF or sustained VT, which included appropriate ICD therapy.

Results

During a median follow-up period of 5.68 (IQR: 4.87–6.70) years, the primary outcome occurred in 44 patients (23%), which included 6 cases of SCD and 38 cases of VT/VF. ICD implant was indicated based on left ventricular ejection fraction (LVEF) of ≤35% (class I recommendation) in 62 patients, with an annualized event rate of 3.93%. A LVEF of >35% with a need for a permanent pacemaker (class IIa recommendation) was observed for 53 patients, with an annualized event rate of 2.54%. A LVEF of >35% with late gadolinium enhancement (LGE) during cardiovascular magnetic resonance (class IIa recommendation) was observed for 62 patients, with an annualized event rate of 2.38% (Figure A). Kaplan-Meier analyses revealed that patients with a class I recommendation for ICD implantation had a significant higher incidence of the primary outcome, compared to patients with a class IIa recommendation and patients with no indication for ICD implantation (P=0.03). However, there were no significant differences in the incidence of the primary outcome between patients with a LVEF of >35% and a need for a permanent pacemaker and patients with a class I recommendation (P=0.08) or patients with a LVEF of ≤35% (P=0.31). Moreover, there was no significant difference in the incidence of the primary outcome between patients with a LVEF of >35% and LGE on cardiovascular magnetic resonance and patients with a class I recommendation (P=0.054) or patients with a LVEF of ≤35% (P=0.22) (Figure B).

Conclusions

The American guideline recommendations for ICD implantation might be applicable to Japanese patients with CS. Implantation of an ICD may need to be considered in these patients if they require a permanent pacemaker or have LGE, regardless of LVEF.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science

Association of high serum soluble interleukin 2 receptor levels with risk of adverse events in patients with cardiac sarcoidosis

Background

Sarcoidosis is a systemic granulomatous disease that affects multiple organs. Among these, the presence of cardiac involvement is recognised as a determinant of worse clinical outcomes. Soluble interleukin 2 receptor (sIL-2R) is a potentially useful biomarker in the diagnosis and evaluation of disease severity in patients with sarcoidosis. However, it remains to be seen whether sIL-2R is associated with the severity and activity of disease in patients with cardiac sarcoidosis (CS).

Purpose

The aims of this study were to investigate whether sIL-2R was associated with clinical outcomes and to clarify the relationship between sIL-2R levels and disease activity evaluated by 18F-fluorideoxyglucose in positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with CS.

Methods

We examined 101 consecutive patients with CS who were admitted to our University HospitalbetweenMay 2003 and February 2020. Patients who had no data of serum sIL-2R levels before initiation of immunosuppressive therapy (n=18) were excluded. Ultimately, 83 patients were examined in this study. The primary outcome was a composite of advanced atrioventricular block (AVB), ventricular tachycardia or ventricular fibrillation (VT/VF), heart failure hospitalisation, and all-cause death. Inflammatory activity in the myocardium and lymph nodes were assessed by18F-FDG PET/CT. We used a published program to analyse the cardiac metabolic activity (CMA), and total lymph node glycolysis (TLyG), which are quantitative measures of FDG volume-intensity.

Results

During a median follow-up period of 2.96 (interquartile range 2.24–4.27) years, the primary outcome occurred in 24 patients (29%), including 1 advanced AVB, 13 VT/VF, 5 hospitalisations for heart failure, and 5 all-cause deaths. Kaplan-Meier analyses showed that the primary outcome occurred more frequently in patients with higher sIL-2R levels (>538 U/mL, the median) than in those with lower sIL-2R levels (Figure). A multivariable Cox regression analysis revealed that a higher sIL-2R level was independently associated with an increased subsequent risk of adverse events (hazard ratio 3.71, 95% confidence interval 1.63–8.44, p=0.002), even after adjustments for age, plasma B-type natriuretic peptide, estimated glomerular filtration rate, left ventricular ejection fraction, and late gadolinium enhancement, which are known to be strong determinants of worse clinical outcomes in patients with CS (Table). Furthermore, sIL-2R levels were significantly correlated with TLyG, the inflammatory activity in lymph nodes (r=0.346, p=0.003) but not with CMA, the inflammatory activity in myocardium (r=0.131, p=0.27).

Conclusions

Increased sIL-2R is associated with worse long-term clinical outcomes accompanied by increased systemic inflammatory activity in CS patients. These findings suggest the importance of assessing sIL-2R as a surrogate marker for further risk stratification in these patients.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Japan Society for the Promotion of Science

Breast cancer surgery in patients with schizophrenia: short-term outcomes from a nationwide cohort

BACKGROUND

Although patients with schizophrenia have a higher risk of developing breast cancer than the general population, studies that have investigated postoperative complications after breast cancer surgery in patients with schizophrenia are scarce. This study examined associations between schizophrenia and short-term outcomes following breast cancer surgery.

METHODS

Patients who underwent surgery for stage 0-III breast cancer between July 2010 and March 2017 were identified from a Japanese nationwide inpatient database. Multivariable analyses were conducted to compare postoperative complications and hospitalization costs between patients with schizophrenia and those without any psychiatric disorder. Three sensitivity analyses were performed: a 1 : 4 matched-pair cohort analysis with matching for age, institution, and fiscal year at admission; analyses excluding patients with schizophrenia who were not taking antipsychotic medication; and analyses excluding patients with schizophrenia who were admitted to hospital involuntarily.

RESULTS

The study included 3660 patients with schizophrenia and 350 860 without any psychiatric disorder. Patients with schizophrenia had a higher in-hospital morbidity (odds ratio (OR) 1.37, 95 per cent c.i. 1.21 to 1.55), with more postoperative bleeding (OR 1.34, 1.05 to 1.71) surgical-site infections (OR 1.22, 1.04 to 1.43), and sepsis (OR 1.20, 1.03 to 1.41). The total cost of hospitalization (coefficient €743, 95 per cent c.i. 680 to 806) was higher than that for patients without any psychiatric disorder. All sensitivity analyses showed similar results to the main analyses.

CONCLUSION

Although causal inferences remain premature, multivariable regression analyses showed that schizophrenia was associated with greater in-hospital morbidity and higher total cost of hospitalization after breast cancer surgery than in the general population.

Rectal cancer lateral lymph nodes: multicentre study of the impact of obturator and internal iliac nodes on oncological outcomes

BACKGROUND

In patients with rectal cancer, enlarged lateral lymph nodes (LLNs) result in increased lateral local recurrence (LLR) and lower cancer-specific survival (CSS) rates, which can be improved with (chemo)radiotherapy ((C)RT) and LLN dissection (LLND). This study investigated whether different LLN locations affect oncological outcomes.

METHODS

Patients with low cT3-4 rectal cancer without synchronous distant metastases were included in this multicentre retrospective cohort study. All MRI was re-evaluated, with special attention to LLN involvement and response.

RESULTS

More advanced cT and cN category were associated with the occurrence of enlarged obturator nodes. Multivariable analyses showed that a node in the internal iliac compartment with a short-axis (SA) size of at least 7 mm on baseline MRI and over 4 mm after (C)RT was predictive of LLR, compared with a post-(C)RT SA of 4 mm or less (hazard ratio (HR) 5.74, 95 per cent c.i. 2.98 to 11.05 vs HR 1.40, 0.19 to 10.20; P < 0.001). Obturator LLNs with a SA larger than 6 mm after (C)RT were associated with a higher 5-year distant metastasis rate and lowered CSS in patients who did not undergo LLND. The survival difference was not present after LLND. Multivariable analyses found that only cT category (HR 2.22, 1.07 to 4.64; P = 0.033) and margin involvement (HR 2.95, 1.18 to 7.37; P = 0.021) independently predicted the development of metastatic disease.

CONCLUSION

Internal iliac LLN enlargement is associated with an increased LLR rate, whereas obturator nodes are associated with more advanced disease with increased distant metastasis and reduced CSS rates. LLND improves local control in persistent internal iliac nodes, and might have a role in controlling systemic spread in persistent obturator nodes.Members of the Lateral Node Study Consortium are co-authors of this study and are listed under the heading Collaborators.

Long-term prognostic significance of dispersion of ventricular repolarization in patients with cardiac sarcoidosis

Background

Although the presence of cardiac involvement is recognised as a determinant of worse clinical outcomes in sarcoidosis patients, the determinants of adverse outcomes in patients with cardiac sarcoidosis (CS) have not been well understood. T-peak to T-end interval (TpTe) on the surface electrocardiogram (ECG) was proposed as a marker of dispersion of ventricular repolarisation. Prolonged TpTe to QT interval ratio (TpTe/QT) represents a period of potential vulnerability to reentrant ventricular arrhythmias. Notably, prolonged TpTe/QT has been associated with increased risk of mortality in hypertrophic cardiomyopathy, congenital long-QT syndrome, and Brugada syndrome. However, its prognostic implication in patients with CS is unclear.

Purpose

We sought to investigate whether TpTe/QT was associated with long-term clinical outcomes in patients with CS.

Methods

A total of 108 consecutive CS patients between August 1986 and March 2019 in two academic hospitals who had ECG data before initiation of immunosuppressive therapy were examined. We excluded patients who received pacemaker (n=15) or cardiac resynchronization therapy (n=3) at the time of ECG. Ultimately, 90 CS patients were included in this study. All standard 12-lead ECGs were recorded at 25 mm/s with an amplification of 10 mm/mV. TpTe was measured from the peak of T wave to the end of T wave which defined as the intersection of the tangent to the down slope of the T wave and the isoelectric line. Lead V5 was selected for the analyses. If V5 is not suitable for analyses, V4 was selected. The primary outcome was the composite of advanced atrioventricular block (AVB), ventricular tachycardia or ventricular fibrillation (VT/VF), heart failure hospitalisation and all-cause death.

Results

During a median follow-up period of 4.70 (interquartile range [IQR] 2.06–7.23) years, adverse events occurred in 21 patients (23.3%), including 2 advanced AVB, 12 VT/VF, 4 heart failure hospitalisation and 3 all-cause death. Events group had higher TpTe/QT compared to no events group (0.231 [IQR 0.193–0.261] vs. 0.282 [IQR 0.263–0.304] P&lt;0.001). Kaplan-Meier analyses revealed that the primary outcome, especially VT/VF or sudden cardiac death more frequently occurred in patients with higher TpTe/QT (≥0.242, the median) compared to those with lower TpTe/QT (Figure 1). Multivariable Cox regression analysis showed that higher TpTe/QT was independently associated with increased subsequent risk of adverse events (hazard ratio 1.09, 95% confidence interval [CI] 1.02–1.17, P=0.014) even after adjustment for age, sex and left ventricular ejection fraction. Furthermore, the optimal cut-off value of TpTe/QT for the discriminatory of primary outcome was 0.257, and c-index was 0.77 (95% CI 0.64–0.89).

Conclusions

Higher TpTe/QT was associated with worse long-term clinical outcomes in patients with CS. Our findings indicate the importance of assessing TpTe/QT for risk stratification in patients with CS.

Figure 1

Funding Acknowledgement

Type of funding source: None

P5366Eicosapentaenoic acid therapy is associated with decreased coronary plaque instability assessed using optical frequency domain imaging

Background

The relationship between eicosapentaenoic acid (EPA) therapy and coronary plaque stability assessed by optical frequency domain imaging (OFDI) has not been thoroughly described.

Hypothesis

EPA therapy is associated with decreased plaque instability in patients undergoing percutaneous coronary intervention (PCI) using OFDI.

Methods

Data on coronary artery plaques from 121 patients presenting with acute coronary syndrome or stable angina who consecutively underwent PCI between October 2015 and July 2018 were retrospectively analyzed. Of these patients, 109 were untreated (no-EPA group), whereas 12 were treated with EPA (EPA group). Each plaque's morphological characteristics were analyzed using OFDI.

Results

We used 1:4 propensity score matching for patients who received or did not receive EPA therapy before PCI. Baseline characteristics were balanced between both groups (age, sex, body mass index, diabetes mellitus, hypertension, dyslipidemia, chronic kidney disease, smoking, previous PCI or coronary artery bypass grafting, previous myocardial infarction, prior statin use, acute coronary syndrome, hemoglobin A1c level, low-density lipoprotein cholesterol concentration, triglyceride concentration, and high-density lipoprotein cholesterol concentration). The EPA group had significantly lower mean lipid index (818±806 vs. 1,574±891) and macrophage grade (13.5±5.9 vs. 19.3±7.4) but higher mean minimum fibrous cap thickness (109.2±55.7 vs. 81.6±36.4 μm) than the no-EPA group (P=0.010, 0.019, and 0.040, respectively). Multiple logistic regression analyses showed that prior EPA use was independently associated with lower lipid index and macrophage grade (P=0.043 and 0.024, respectively).

Conclusion

This OFDI analysis suggests that EPA therapy is associated with decreased plaque instability in patients undergoing PCI.

Acknowledgement/Funding

None

Prognostic impact of residual lateral lymph node metastasis after neoadjuvant (chemo)radiotherapy in patients with advanced low rectal cancer

Background

There is a lack of large studies focusing on the prognostic significance of lateral lymph node (LLN) metastasis following LLN dissection (LLND) in rectal cancer. The aim of this study was to evaluate the prognostic impact of LLN metastases on survival of patients with advanced low rectal cancer.

Methods

Consecutive patients with locally advanced, but not metastatic, extraperitoneal rectal cancer treated with neoadjuvant (chemo)radiotherapy plus total mesorectal excision between 2004 and 2015 were included in the study. LLND was performed when pretreatment imaging documented enlarged LLNs (7 mm or greater in size). Localization of nodal metastases and long‐term outcomes were analysed. Kaplan–Meier analysis was used to compare the survival of patients with ypN0 disease with that of patients with mesorectal ypN+/LLN− status and patients with positive LLNs. The Cox proportional hazards model was used to evaluate predictors of disease‐free survival (DFS) and local recurrence.

Results

A total of 613 patients were included in the study; LLND was performed in 212 patients (34·6 per cent) and 57 (9·3 per cent) had LLN metastasis. Patients with LLN metastasis had improved DFS and local recurrence cumulative incidence rates compared with patients with mesorectal ypN2+/LLN− disease (DFS: P = 0·014; local recurrence: P = 0·006). Although the DFS rate of patients with LLN metastasis was worse than that of patients with ypN0 disease (P < 0·001), the cumulative incidence of local recurrence was similar (P = 0·491). In multivariable analysis, residual LLN metastasis was not an independent predictor of worse DFS or local recurrence.

Conclusion

LLN metastasis is not an independent predictor of local recurrence or survival. Survival of patients presenting with LLN metastasis after (chemo)radiotherapy was intermediate between that of patients with ypN0 status and those with mesorectal ypN2 positivity.

IMAGING URANIUM DISTRIBUTION ON RAT KIDNEY SECTIONS THROUGH DETECTION OF ALPHA TRACKS USING CR-39 PLASTIC NUCLEAR TRACK DETECTOR

Uranium is renowned as a global contaminant, and attracts major concern with regards to the health risks involved because its nephrotoxicity. This paper discusses the development of a simple method to identify accumulated regions or localized sites of uranium within kidneys using the CR-39 plastic nuclear track detector. To demonstrate the proposed method, renal cryo-sections (5 μm-t) from Wistar male rats, subcutaneously administered with uranyl acetate (2 mg/kg), were prepared on day one after administration. Concerned sections were subsequently placed on CR-39, stored for 1.25 years, and then etched in a 7 M NaOH solution at 70°C for 3 h. α-tracks were then detected in the form of etch pits, corresponding to uranium, and also the tissue shape and structure were transferred as a roughness on the surface of CR-39. As observed, the proposed method served to facilitate simultaneous detection and identification of localized regions of uranium accumulation within kidneys.

BYSTANDER WI-38 CELLS MODULATE DNA DOUBLE-STRAND BREAK REPAIR IN MICROBEAM-TARGETED A549 CELLS THROUGH GAP JUNCTION INTERCELLULAR COMMUNICATION

Bi-directional signaling involved in radiation-induced bystander effect (RIBE) between irradiated carcinoma cells and their surrounding non-irradiated normal cells is relevant to radiation cancer therapy. Using the SPICE-NIRS microbeam, we delivered 500 protons to A549-GFP lung carcinoma cells, stably expressing H2B-GFP, which were co-cultured with normal WI-38 cells. The level of γ-H2AX, a marker for DNA double-strand breaks (DSB), was subsequently measured up to 24-h post-irradiation in both targeted and bystander cells. As a result, inhibition of gap junction intercellular communication (GJIC) attenuated DSB repair in targeted A549-GFP cells, and suppressed RIBE in bystander WI-38 cells but not in distant A549-GFP cells. This suggests that GJIC plays a two-way role through propagating DNA damage effect between carcinoma to normal cells and reversing the bystander signaling, also called 'rescue effect' from bystander cells to irradiated cells, to enhance the DSB repair in targeted cells.

DOSE-RATE AND CELL-KILLING SENSITIVITY OF HIGH-LINEAR ENERGY TRANSFER ION BEAM

It is believed that the dose-rate of radiation will have an influence on cell sensitivity. The dose-rate effects on cell survival can be expressed by the change of the β term in the linear quadratic model. The value at a high-dose-rate decreases below 60 Gy/h and reaches zero at 0.2 Gy/h or less for photons. However, the effect for a high-LET ion-beam is not well known. At HIMAC, cells were exposed to 70 keV/μm carbon-ion beams at different dose-rates between 0.5 and 600 Gy/h at room temperature. The β values for all survival curves show no significant differences among the dose-rates tested for HSG, V79 and CHO cells. Changing the ion-beam dose-rate had no effect on cell survival. This suggests that high-LET particle beams, such as galactic cosmic rays, may not exhibit a dose-rate effect on cell survival. Low-dose-rate radiation showed an effect similar to high-dose-rate radiation.

Randomized clinical trial of 24 versus 72 h antimicrobial prophylaxis in patients undergoing open total gastrectomy for gastric cancer

BACKGROUND

Open total gastrectomy carries a high risk of surgical-site infection (SSI). This study evaluated the non-inferiority of antimicrobial prophylaxis for 24 compared with 72 h after open total gastrectomy.

METHODS

An open-label, randomized, non-inferiority study was conducted at 57 institutions in Japan. Eligible patients were those who underwent open total gastrectomy for gastric cancer. Patients were assigned randomly to continued use of β-lactamase inhibitor for either 24 or 72 h after surgery. The primary endpoint was the incidence of SSI, with non-inferiority based on a margin of 9 percentage points and a 90 per cent c.i. The secondary endpoint was the incidence of remote infection.

RESULTS

A total of 464 patients (24 h prophylaxis, 228; 72 h prophylaxis, 236) were analysed. SSI occurred in 20 patients (8·8 per cent) in the 24-h prophylaxis group and 26 (11·0 per cent) in the 72-h group (absolute difference -2·2 (90 per cent c.i. -6·8 to 2·4) per cent; P < 0·001 for non-inferiority). However, the incidence of remote infection was significantly higher in the 24-h prophylaxis group.

CONCLUSION

Antimicrobial prophylaxis for 24 h after total gastrectomy is not inferior to 72 h prophylaxis for prevention of SSI. Shortened antimicrobial prophylaxis might increase the incidence of remote infection. Registration number: UMIN000001062 ( http://www.umin.ac.jp).

Spatial regularity of InAs-GaAs quantum dots: quantifying the dependence of lateral ordering on growth rate

The lateral ordering of arrays of self-assembled InAs-GaAs quantum dots (QDs) has been quantified as a function of growth rate, using the Hopkins-Skellam index (HSI). Coherent QD arrays have a spatial distribution which is neither random nor ordered, but intermediate. The lateral ordering improves as the growth rate is increased and can be explained by more spatially regular nucleation as the QD density increases. By contrast, large and irregular 3D islands are distributed randomly on the surface. This is consistent with a random selection of the mature QDs relaxing by dislocation nucleation at a later stage in the growth, independently of each QD’s surroundings. In addition we explore the statistical variability of the HSI as a function of the number N of spatial points analysed, and we recommend N > 10³ to reliably distinguish random from ordered arrays.

Randomized clinical trial of oral and intravenous versus intravenous antibiotic prophylaxis for laparoscopic colorectal resection

Background

The use of oral prophylactic antibiotics for the prevention of surgical-site infection (SSI) in patients undergoing laparoscopic surgery for colorectal cancer is controversial. The aim of this RCT was to evaluate whether intravenous perioperative antibiotics are inferior to combined preoperative oral and perioperative intravenous antibiotics in this setting.

Methods

Patients undergoing elective laparoscopic colorectal resection in a single cancer centre were assigned randomly to combined preoperative oral antibiotics (metronidazole and kanamycin) and perioperative intravenous antibiotics (cefmetazole) (oral/IV group) or to perioperative intravenous antibiotics (cefmetazole) alone (IV-only group). Patients were stratified for the analyses based on type of operation (colonic surgery, anterior resection or abdominoperineal resection), preoperative use of mechanical bowel preparation, preoperative chemoradiotherapy and the presence of diabetes mellitus. The primary endpoint was the overall rate of SSI. Secondary endpoints were the rates of incisional site infection, organ/space infection, anastomotic leakage, intra-abdominal abscess, adverse events and postoperative complications.

Results

Of 540 patients offered participation in the trial in 2013–2014, 515 agreed to take part and were randomized. Some 256 patients in the IV-only group and 255 in the oral/IV group completed the treatment per protocol. The overall rate of SSI was 7·8 per cent (20 of 256) in the IV-only group and 7·8 per cent (20 of 255) in the oral/IV group, confirming that perioperative administration of intravenous antibiotics alone was not inferior to the combined regimen (P = 0·017). There were no differences in rates of incisional site infection (5·5 versus 5·9 per cent respectively), organ/space infection (2·3 versus 2·0 per cent) or other secondary endpoints between the two groups.

Conclusion

Intravenous perioperative antimicrobial prophylaxis alone is not inferior to combined preoperative oral and intravenous perioperative prophylaxis with regard to SSI in patients with colorectal cancer undergoing elective laparoscopic resection. Registration number: UMIN000019339 (http://www.umin.ac.jp/ctr/).

Laparoscopic salvage lateral pelvic lymph node dissection for locally recurrent rectal cancer

AIM

The lateral pelvic lymph nodes are one of the major sites and sources of local recurrence (LR) after surgery for rectal cancer. Salvage lateral pelvic lymph node dissection (LPLD) is potentially curative, but the value of laparoscopic surgery in such cases is unknown. Our aim was to report the technical details of laparoscopic salvage LPLD for LR at these nodes after rectal cancer surgery.

METHOD

The study was based on nine patients who underwent laparoscopic salvage LPLD for LR at the lateral pelvic lymph nodes after surgery for rectal cancer. The safety and feasibility of this procedure were determined.

RESULTS

The median operation time was 381 min and the median estimated blood loss was 130 ml. There were no conversions. Adjacent structures removed en bloc were the pelvic plexus in four patients, the internal iliac artery in seven patients and the seminal vesicle in one patient. The median number of metastatic lymph nodes was 1 (range 1-11).

CONCLUSION

Our novel technique of laparoscopic salvage LPLD for LR at the lateral pelvic lymph nodes is safe and feasible.

Bystander effect between zebrafish embryos in vivo induced by high-dose X-rays

We employed embryos of the zebrafish, Danio rerio, for our studies on the in vivo bystander effect between embryos irradiated with high-dose X-rays and naive unirradiated embryos. The effects on the naive whole embryos were studied through quantification of apoptotic signals at 25 h post fertilization (hpf) through the terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay followed by counting the stained cells under a microscope. We report data showing that embryos at 5 hpf subjected to a 4-Gy X-ray irradiation could release a stress signal into the medium, which could induce a bystander effect in partnered naive embryos sharing the same medium. We further demonstrated that this bystander effect (induced through partnering) could be successfully suppressed through the addition of the nitric oxide (NO) scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) into the medium but not through the addition of the CO liberator tricarbonylchloro(glycinato)ruthenium(II) (CORM-3). This shows that NO was involved in the bystander response between zebrafish embryos induced through X-ray irradiation. We also report data showing that the bystander effect could be successfully induced in naive embryos by introducing them into the irradiated embryo conditioned medium (IECM) alone, i.e., without partnering with the irradiated embryos. The IECM was harvested from the medium that had conditioned the zebrafish embryos irradiated at 5 hpf with 4-Gy X-ray until the irradiated embryos developed into 29 hpf. NO released from the irradiated embryos was unlikely to be involved in the bystander effect induced through the IECM because of the short life of NO. We further revealed that this bystander effect (induced through IECM) was rapidly abolished through diluting the IECM by a factor of 2× or greater, which agreed with the proposal that the bystander effect was an on/off response with a threshold.

Zinc-substituted hydroxyapatite: a biomaterial with enhanced bioactivity and antibacterial properties

Hydroxyapatite (HA) is a synthetic biomaterial and has been found to promote new bone formation when implanted in a bone defect site. However, its use is often limited due to its slow osteointegration rate and low antibacterial activity, particularly where HA has to be used for long term biomedical applications. This work will describe the synthesis and detailed characterization of zinc-substituted HA (ZnHA) as an alternative biomaterial to HA. ZnHA containing 1.6 wt% Zn was synthesized via a co-precipitation reaction between calcium hydroxide, orthophosphoric acid and zinc nitrate hexahydrate. Single-phase ZnHA particles with a rod-like morphology measuring ~50 nm in length and ~15 nm in width, were obtained and characterized using transmission electron microscopy and X-ray diffraction. The substitution of Zn into HA resulted in a decrease in both the a- and c-axes of the unit cell parameters, thereby causing the HA crystal structure to alter. In vitro cell culture work showed that ZnHA possessed enhanced bioactivity since an increase in the growth of human adipose-derived mesenchymal stem cells along with the bone cell differentiation markers, were observed. In addition, antibacterial work demonstrated that ZnHA exhibited antimicrobial capability since there was a significant decrease in the number of viable Staphylococcus aureus bacteria after in contact with ZnHA.

Peierls mechanism of the metal-insulator transition in ferromagnetic hollandite K2Cr8O16

Synchrotron x-ray diffraction experiment shows that the metal-insulator transition occurring in a ferromagnetic state of a hollandite K(2)Cr(8)O(16) is accompanied by a structural distortion from the tetragonal I4/m to monoclinic P112(1)/a phase with a √2×√2×1 supercell. Detailed electronic structure calculations demonstrate that the metal-insulator transition is caused by a Peierls instability in the quasi-one-dimensional column structure made of four coupled Cr-O chains running in the c direction, leading to the formation of tetramers of Cr ions below the transition temperature. This provides a rare example of the Peierls transition of fully spin-polarized electron systems.

Drug discontinuation after treatment with minimum maintenance dose of an antithyroid drug in Graves' disease: a retrospective study on effects of treatment duration with minimum maintenance dose on lasting remission

According to the guideline issued by the Japan Thyroid Association in 2006 for treatment of Graves' disease, discontinuing antithyroid drug (ATD) therapy is recommended when serum free thyroxine (FT4) and thyroid stimulating hormone (TSH) concentrations have been maintained within the reference range for a certain period after treatment with one ATD tablet every other day (minimum maintenance dose therapy, MMDT). In this retrospective study, the relationship between MMDT duration and remission rate was investigated. The participants were 107 consecutive patients with Graves' disease whose ATD therapy was stopped according to the guideline. Serum FT4, TSH, and TSH receptor antibody (TRAb) levels were measured when ATD was discontinued and every 3 months thereafter. The percentage of patients in remission was 86.9% at 6 months, 73.8% at 1 year, and 68.2% at 2 years after ATD discontinuation. The remission rate increased with MMDT duration, being significantly higher in patients with MMDT durations of 19 months or more than those with MMDT durations of 6 months or less. In patients with MMDT durations of 6 months or less, the remission rate was significantly lower in TRAb-positive patients than in TRAb-negative patients at the time of withdrawal of ATD; however, this was not observed in patients with MMDT durations of 7 months or more. These findings suggest that in patients who discontinue ATD after a certain MMDT duration, the remission rate increases as the MMDT duration increases, and ATD should not be discontinued in TRAb-positive patients with MMDT durations of 6 months or less.

Persistent high TRAb values during pregnancy predict increased risk of neonatal hyperthyroidism following radioiodine therapy for refractory hyperthyroidism

Serum levels of TSH receptor antibody (TRAb) often increase after radioiodine treatment for Graves' disease, and high-serum levels of maternal TRAb in late pregnancy indicate a risk of neonatal hyperthyroidism. The aim of this retrospective study is to investigate the characteristics of Graves' women who had a history of radioiodine treatment for intractable Graves' disease, and whose neonates suffered from hyperthyroidism. The subjects of this study were 45 patients with Graves' disease who became pregnant during the period from 1988 to 1998 after receiving radioiodine treatment at Ito Hospital. 25 of the 45 subjects had had a relapse of hyperthyroidism after surgical treatment for Graves' disease. 19 pregnancies were excluded because of artificial or spontaneous abortion. In the remaining 44 pregnancies of 35 patients, neonatal hyperthyroidism developed in 5 (11.3%) pregnancies of 4 patients. Serum levels of TRAb at delivery were higher in patients whose neonates suffered from hyperthyroidism (NH mother) than those of patients who delivered normal infants (N mother). Furthermore, serum levels of TRAb in NH mother did not change during pregnancy, although those of 4 patients of N mother, in which serum levels of TRAb before radioiodine treatment were as high as in NH mother, decreased significantly during pregnancy. In conclusion, women who delivered neonates with hyperthyroidism following radioiodine treatment seem to have very severe and intractable Graves' disease. Persistent high TRAb values during pregnancy observed in those patients may be a cause of neonatal hyperthyroidism.

[Pericardiocentesis and drainage]

Diagnosis and treatment of pericardial effusion need to be performed frequently by pericardiocentesis or surgical pericardiotomy. Large retention of the effusion is treated conventionally by percutaneous blind puncture, while possible injuries to the myocardium are avoided feasibly by ultrasonically-guided puncture even in case that the effusion remains moderately or unevenly inside the pericardial space. Along with the puncture, drainage tube introduced into the pericardial sac using coaxial method contributes to relieving coexistent pericardial or chronic exudation. The pericardium is also surgically approached traditionally via parasternal, subxiphoid, or lateral-thoracic route. Specimen of the pericardium is optionally sampled to promote analyzing the pathogenesis, and drainage tubes of larger diameter facilitate evacuating the purulent substance in the settings of infectious origins. The lateral thoracotomy is occasionally applied to the effusion around the posterior aspect of the heart, which is preferably replaced by less-invasive video-assisted procedure. Those several measures would facilitate the treatment for pericardial effusion.

Measuring thyroglobulin autoantibodies by sensitive assay is important for assessing the presence of thyroid autoimmunity in areas with high iodine intake

There is some debate over the clinical utility of measuring serum TgAb to assess the presence of thyroid autoimmunity. To clarify the relationship between TgAb levels and thyroid autoimmunity, a histological examination of thyroid tissue was carried out on unselected living individuals with detectable serum TgAb. 146 patients with a pathological diagnosis of follicular adenoma were selected as subjects. Focal lymphocytic infiltration (FLI) was defined as lymphocytic aggregates of more than 200 in number. A thyroid gland in which 0-1 FLI was observed in a few visual fields of low magnification (20 x 4) in thyroid tissue adjacent to a tumor was judged to be normal and a thyroid gland in which 2 or more FLI were observed was diagnosed as focal lymphocytic thyroiditis (FLT). Serum levels of TgAb and TPOAb were measured by radioimmunoassay. Out of the 146 patients, 18 had detectable serum TgAb and 16 had detectable serum TPOAb. All but one (i.e. 94%) of the 18 TgAb positive patients had FLT and 14 out of the 16 TPOAb positive patients had FLT. The sensitivity (17/32; 53.1%) and specificity (113/114; 99.1%) of TgAb for detecting FLT were higher than those (14/32; 43.7% and 112/114; 98.2%) of TPOAb, but the differences were not significant. In 9 patients who were TgAb positive (but TPOAb negative), 8 (88.9%) had FLT. These results throw doubt on the Laboratory medicine practice guidelines published in Thyroid 2003, in which measuring TgAb is not usually necessary for detecting autoimmune thyroid disease. At least measuring TgAb by sensitive assay is useful for assessing the presence of thyroid autoimmunity in Japan, an area with high iodine intakes.

Websites offer helpful information concerning consultation with headache specialists

Patients with severe primary headache may benefit from consultation with headache specialists, but doctor attendance rates in Japan are very low. More headache patients might consult headache specialists if these specialists were more widely recognized by the public. To determine what information prompted patients to seek consultation with a headache specialist, we questioned 256 primary headache patients about the source of the helpful information concerning consultation with headache specialists. From 191 patients, a total of 235 responses to the questionnaire were obtained. The most common response was ‘websites’ (33.2%), followed by ‘professionals’ (23.8%), ‘acquaintances’ (20.9%), ‘print media’ (6.8%) and ‘TV/radio’ (3.4%). Patients who indicated websites showed the most severe pain and highest impact of headache, and accounted for 52.4% of those with cluster headaches. Development of websites concerning headache specialists would seem likely to increase doctor attendance rates for patients with primary headache.

On the interface magnetism of thin oxidized Co films: orbital and spin moments

An x-ray magnetic circular dichroism study of a polycrystalline Co/CoO bilayer is presented. Using both the chemical specificity and surface sensitivity in the core level techniques, we find that uncompensated Co(2+) spin moments participate in the remanent ferromagnetic response of the bilayer that has oxygen nearest neighbors. These are likely located at the Co/CoO interface. As intermixing of magnetic species is not present in Co/CoO, it is concluded that the observed interface moments are due to interface roughness. Given their direction, these moments appear to not directly correlate to the exchange bias in these bilayers.

Glimepiride increases high-density lipoprotein cholesterol via increasing adiponectin levels in type 2 diabetes mellitus

The aims of the present study are to investigate the effect of glimepiride 1 mg/d on plasma adiponectin and to assess the contribution of adiponectin in changing high-density lipoprotein cholesterol (HDL-c) levels after glimepiride treatment. Forty patients with type 2 diabetes mellitus were included. Plasma adiponectin, fasting plasma glucose, insulin, hemoglobin A(1c), and cholesterol were measured at study entry and after 3 months of treatment with glimepiride. Both plasma adiponectin level (7.5 +/- 4.5 vs 8.3 +/- 4.5 microg/mL, P = .040) and HDL-c level increased significantly (50 +/- 11 vs 53 +/- 10 mg/dL, P = .041) in the all-subjects group. In the low-adiponectin group (initial plasma adiponectin level <6 microg/mL), both plasma adiponectin level (4.5 +/- 0.9 vs 5.9 +/- 2.0 microg/mL, P = .004) and HDL-c level increased significantly (44 +/- 8 vs 49 +/- 9 mg/dL, P = .011). There was no significant change in the high-adiponectin group (initial plasma adiponectin level >or=6 microg/mL). Change in plasma adiponectin level was an independent factor for change in HDL-c level after adjustment for other factors (beta = .574, P = .009, R(2) = 0.524, P = .036). In conclusion, glimepiride improved plasma adiponectin level, especially in the subjects with type 2 diabetes mellitus with low adiponectin level before treatment, and may directly contribute to improving HDL-c level.

Effects of pravastatin on serum osteoprotegerin levels in patients with hypercholesterolemia and type 2 diabetes

Osteoprotegerin is a secretory glycoprotein. Recent experimental findings have suggested that osteoprotegerin may protect against vascular calcification and/or atherosclerosis. In humans, osteoprotegerin levels are positively correlated with the presence and severity of coronary artery disease and the progression of atherosclerosis. However, it is unclear how osteoprotegerin levels are regulated. Statins are known to have beneficial pleiotropic effects against atherosclerosis beyond their lipid-lowering effects. In this study, we examined whether treatment with pravastatin can alter osteoprotegerin levels in patients with hypercholesterolemia and type 2 diabetes. Osteoprotegerin levels were significantly increased from 6.64 +/- 2.18 pmol/L at baseline to 7.08 +/- 2.29 pmol/L (P = .024) after 3-month treatment with pravastatin. These increases in osteoprotegerin levels remained after 6 months of treatment (7.05 +/- 2.22 pmol/L, P = .026). These findings suggest that pravastatin may exert its pleiotropic effects in part through alteration of osteoprotegerin levels.

[A new technique of aortic occlusion in patient with severe aortic calcification]

A 63-year-old woman with severe aortic valve insufficiency and bilateral subclavian artery occlusion underwent ascending aorta-to-biaxillary artery bypass and aortic valve replacement, simultaneously. Because of severe aortic calcification, a hand-made aortic occluder was utilized to prevent embolic stroke. We believe that the new technique of aortic occllusion might be very useful for patients with severe aortic calcification.

A novel goose-type lysozyme gene with chitinolytic activity from the moderately thermophilic bacterium Ralstonia sp. A-471: cloning, sequencing, and expression

In this study, we cloned the gene encoding goose-type (G-type) lysozyme with chitinase (Ra-ChiC) activity from Ralstonia sp. A-471 genomic DNA library. This is the first report of another type of chitinase after the previously reported chitinases ChiA (Ra-ChiA) and ChiB (Ra-ChiB) in the chitinase system of the moderately thermophilic bacterium, Ralstonia sp. A-471 and also the first such data in Ralstonia sp. G-type lysozyme gene. It consisted of 753 bp nucleotides, which encodes 251 amino acids including a putative signal peptide. This ORF was modular enzyme composed of a signal sequence, chitin-binding domain, linker, and catalytic domain. The catalytic domain of Ra-ChiC showed homologies to those of G-type lysozyme (glycoside hydrolases (GH) family 23, 16.8%) and lysozyme-like enzyme from Clostridium beijerincki (76.1%). Ra-ChiC had activities against ethylene glycol chitin, carboxyl methyl chitin, and soluble chitin but not against the cell wall of Micrococcus lysodeikticus. The enzyme produced alpha-anomer by hydrolyzing beta-1,4-glycosidic linkage of the substrate, indicating that the enzyme catalyzes the hydrolysis through an inverting mechanism. When N-acetylglucosamine hexasaccharide [(GlcNAc)6] was hydrolyzed by the enzyme, the second and third glycosidic linkage from the non-reducing end were split producing (GlcNAc)2 + (GlcNAc)4 and (GlcNAc)3 + (GlcNAc)3 of almost the same concentration in the early stage of the reaction. The G-type lysozyme hydrolyzed (GlcNAc)6 in an endo-splitting manner, which produced (GlcNAc)3 + (GlcNAc)3 predominating over that to (GlcNAc)2 + (GlcNAc)4. Thus, Ra-ChiC was found to be a novel enzyme in its structural and functional properties.