Impact of deep learning on radiologists and radiology residents in detecting breast cancer on CT: a cross-vendor test study

AIM

To investigate the effect of deep learning on the diagnostic performance of radiologists and radiology residents in detecting breast cancers on computed tomography (CT).

MATERIALS AND METHODS

In this retrospective study, patients undergoing contrast-enhanced chest CT between January 2010 and December 2020 using equipment from two vendors were included. Patients with confirmed breast cancer were categorised as the training (n=201) and validation (n=26) group and the testing group (n=30) using processed CT images from either vendor. The trained deep-learning model was applied to test group patients with (30 females; mean age = 59.2 ± 15.8 years) and without (19 males, 21 females; mean age = 64 ± 15.9 years) breast cancer. Image-based diagnostic performance of the deep-learning model was evaluated with the area under the receiver operating characteristic curve (AUC). Two radiologists and three radiology residents were asked to detect malignant lesions by recording a four-point diagnostic confidence score before and after referring to the result from the deep-learning model, and their diagnostic performance was evaluated using jackknife alternative free-response receiver operating characteristic analysis by calculating the figure of merit (FOM).

RESULTS

The AUCs of the trained deep-learning model on the validation and test data were 0.976 and 0.967, respectively. After referencing with the result of the deep learning model, the FOMs of readers significantly improved (reader 1/2/3/4/5: from 0.933/0.962/0.883/0.944/0.867 to 0.958/0.968/0.917/0.947/0.900; p=0.038).

CONCLUSION

Deep learning can help radiologists and radiology residents detect breast cancer on CT.

Enrichment in procoagulant microparticles in calcified human aortic valve – role in valvular endothelium alterations and enhanced thrombogenicity

Background

Aortic stenosis (AS) is characterized by endothelial dysfunction (ED), inflammatory cell infiltration, myofibroblastic and osteoblastic differentiation. Subclinical leaflet thrombosis was recently linked to higher rates of stroke and transient ischemic attack after transcatheter aortic valve implantation (TAVI). Procoagulant microparticles (MPs) are associated with ED, inflammation and clot formation. There is limited evidence regarding intra-valvular MPs content and their potential biological effects. This question is particularly relevant in TAVI in which the residing native valve could constitute a source of thrombotic activity enhancing leaflet thrombosis and valve dysfunction.

Purpose

Therefore, we hypothesized that MPs trapped within the native aortic valve contribute to valvular dysfunction including enhanced thrombogenicity.

Methods

Human valves were collected from patients undergoing surgical valve replacement for AS or aortic insufficiency (AI). Pro-thrombotic, pro-inflammatory, and ED markers were identified in the calcified vs non-calcified part of the valves by Western-blot. Calcium content was measured through colorimetric method. MPs were extracted from human pathological valves, and quantified through their prothrombinase activity. Primary cultures of porcine valvular endothelial cells (VEC) were treated with the MPs (10 nmol/L) or thrombin (1U/ml) for 24hrs. Phenotypic change was appreciated through gene expression pattern assessed by RT-qPCR. IL-8 secretion was measured by ELISA.

Results

The phenotype of the AS valve was characterized through increased expression of thrombogenic (tissue factor, thrombomodulin, PAI-1), adhesive (VCAM-1, ICAM-1) and inflammatory (COX-1, COX-2) molecules in the calcified part of the valve. Moreover, MPs content was increased in the calcified vs non-calcified part of the valve or AI valves. MPs levels was correlated with valvular calcium content (R=0.3862: p<0.001). Tissue factor was increased in MPs extracted from AS vs AI. The biological effect of MPs was tested on VEC in-vitro. Results showed dramatic increase in expression of inflammatory cytokines (CXCL10, CCL11, CXCL8, MCP1) adhesion molecules (VCAM-1, ICAM-1, SELP, SELE) and proangiogenic factors (VEGFR2, ANGPTL4) in VEC exposed to MPs (24h) from AS vs AI. Enhanced secretory phenotype was evidenced through IL-8 determination in the supernatant of VEC stimulated with MPs from AS valve.

Conclusion

Calcified aortic valve is a potent reservoir of MPs, acting as a pro-thrombogenic source per se and promoting a switch of VEC phenotype toward prothrombotic, proinflammatory and proangiogenic pattern. These data suggest that MPs released from the native valve constitute an important source of mediators involved in enhanced thrombogenicity and valvular remodeling.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): GERCA-Groupe Etudes Reali Commercia Avignon

Optimisation of Radiation Therapy in Bladder Preservation Therapy for Patients With Clinical Stage T2N0M0 Bladder Cancer

AIMS

A novel bladder preservation therapy, the OMC (Osaka Medical College) regimen, which combines radiation therapy with balloon-occluded arterial infusion of anticancer agents, is a treatment option for patients with muscle-invasive bladder cancer (MIBC). We retrospectively analysed the effects of changes in radiation dose and irradiation field on treatment efficacy and adverse events.The purpose of this study is to use the results of this study to help determine a course of radiation therapy for bladder preservation therapy of cT2N0M0 MIBC.

MATERIALS AND METHODS

We examined 352 patients with clinical stage T2N0M0 (cT2N0M0) MIBC classified into the following groups based on the irradiation method: group A, the whole pelvis (50 Gy/25 fractions) + local bladder (10 Gy/5 fractions); group B, the small pelvis (50 Gy/25 fractions) + local bladder (10 Gy/5 fractions); group C, the whole pelvis (40 Gy/20 fractions) + local bladder (10 Gy/5 fractions).

RESULTS

The complete response rate, 3-year overall survival and progression-free survival rates in group A were 92.9%, 94.9% and 82.1%, respectively; in group B were 87.2%, 86.7% and 76.7%, respectively; and in group C were 95.2%, 92.6% and 71.1%, respectively. No significant differences between the groups were noted. The incidence of ≥grade 3 urinary tract and gastrointestinal toxicities were not significantly different among the groups (group A: 7.8%, 1.7%; B, 11.1%, 0%; C, 7.1%, 1.8%, respectively). The 3-year progression-free rates of the common iliac lymph node (CILN) region in patients who received whole-pelvis and small-pelvis irradiation were 99.0 and 89.0% (P < 0.01), respectively, with the latter group having significantly high lymph node recurrence in the CILN region.

CONCLUSIONS

Our findings showed that the optimal radiation therapy for patients with cT2N0M0 MIBC undergoing the OMC regimen is whole-pelvis irradiation including the CILN region, with a total dose of 50 Gy/25 fractions.

Primary hemostatic disorders drive early and late major bleedings of patients with atrial fibrillation after transcatheter aortic valve replacement

Introduction

Patients with atrial fibrillation (AF) are likely to have multiple co-morbidities and receive anticoagulants after TAVR, which lead to a poor prognosis including bleeding events. Closure time adenosine diphosphate (CT-ADP) is a primary hemostasis point-of-care test used as a surrogate marker of high molecular weight (HMW) multimers defect of Von Willebrand factor (VWF). Our prior studies suggest that prolongation of CT-ADP (&gt;180 seconds) after TAVR is a major determinant of early and late major/life-threatening bleeding complications (MLBCs).

Purpose

To evaluate the impact of post-procedural CT-ADP &gt;180sec on bleeding events in AF patients.

Methods

We included 878 patients from our prospective TAVR registry between 2010 and 2019. Bleeding complications were assessed according to the VARC-2 (Valve Academic Research Consortium-2) criteria. Major adverse cardiac and cerebrovascular events (MACCE) was defined as a composite of all-cause death, myocardial infarction, stroke, and heart failure hospitalization within 1-year after TAVR. Ongoing primary haemostasis disorder was defined by post-procedure CT-ADP &gt;180sec. Primary endpoint was the occurrence of MLBCs during the first year and the second endpoint was 1-year MACCE.

Results

Patients with AF had a higher incidence of all-cause mortality (15% vs. 8%, p=0.002), MACCE (29% vs. 20%, p=0.002), and MLBCs (20% vs. 12%, p=0.001) within 1-year compared to non-AF patients. When the cohort was split into 4 subgroups according to AF and CT-ADP &gt;180sec, patients with AF and CT-ADP &gt;180sec had the highest risk of MLBCs (log-rank test; p&lt;0.001) (Figure). Multivariate Cox regression analysis confirmed that the patients with AF and CT-ADP &gt;180sec had 4.6-fold higher risk of MLBCs within 1 year compared to non-AF patients with CT-ADP ≤180sec (hazard ratio: 4.60; 95% confidence interval: 2.18 - 9.68; p&lt;0.001).

Conclusion

Among TAVR patients, AF with post-procedural CT-ADP &gt;180 sec was identified as a strong independent predictor of MLBCs at 1-year follow-up. Our study suggest that persistent primary haemostasis disorders contribute to a higher risk of bleeding events particularly in AF patients and may be considered for a tailored and risk-adjusted antithrombotic therapy after TAVR.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Dr Matsushita received a grant from Edwards Lifesciences.

Protective effects of dapagliflozin on vascular remodeling in the carotid artery following balloon injury – potential role of angiotensin and purinergic signaling

Introduction

Sodium-glucose co-transporter 2 (SGLT2) inhibitors have been shown to reduce the risk of cardiovascular events independently of glycemic control. The possibility that SGLT2 inhibitors improve endothelial regeneration and vascular restenosis is unknown.

Purpose

To examine whether dapagliflozin, a selective SGLT2 inhibitor, could prevent neointima thickening induced by balloon injury and, if so, to determine the underlying mechanisms. The effect of dapagliflozin was compared to that of losartan, an angiotensin type 1 receptor (AT1R) antagonist.

Methods

Saline, dapagliflozin (1.5 mg/kg/day), or losartan (30 mg/kg/day) were administered orally for 5 weeks to male Wistar rats. Balloon injury of the left carotid artery was performed 1 week after starting the treatment and sacrificed 4 weeks later. Vascular reactivity was assessed on left (injured) and right (healthy) carotid artery rings. The extent of neointima was assessed by histomorphometric analysis, changes of target factors by immunofluorescence, RT-qPCR and histochemistry.

Results

Dapagliflozin and losartan treatments reduced neointima thickening by 32% and 27%, respectively. Blunted contractile responses to phenylephrine and relaxations to acetylcholine and down-regulation of eNOS were observed in the injured artery. These effects were not modified by the dapagliflozin or the losartan treatments. RT-qPCR investigations indicated an increased in gene expression of inflammatory (IL-1beta, ITGAM, VCAM-1), oxidative (p47phox, p22phox) and fibrotic (TGF-beta1) markers and a decreased of eNOS in the injured carotid. However, these changes were not affected by the pharmacological treatments. By contrast, significant increased levels of AT1R angiotensin receptor and NTPDase1 (CD39) ectonucleotidase were observed in the restenotic carotid artery of the dapagliflozin group. Histochemical analysis evidenced important NTPDase1 activity in the neointima.

Conclusions

Dapagliflozin effectively reduced neointimal thickening. As the contribution of AT1R and P2Y2 ATP receptor in smooth muscle cell proliferation and neointima formation has been reported in the literature, the present data suggest that dapagliflozin prevents restenosis through interfering with angiotensin and/or extracellular nucleotides signaling. SGLT2 transporter represent potential new target for limiting vascular restenosis.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This work was supported by AstraZeneca

Venous thromboembolism in non-critically ill patients with COVID-19 infection

Background

Systemic coagulation activation and thrombotic complications are frequent among critically ill patients with COVID-19. Limited data are available in non-intensive care unit (ICU) patients.

Purpose

To determine the incidence, risk factors and prognosis of venous thromboembolism (VTE) in non-ICU COVID-19 patients.

Methods

We studied consecutive COVID-19 patients admitted to general ward at Strasbourg Hospital, France (25.02.2020–19.04.2020). The primary outcome was any VTE complication. The secondary outcome was the composite of death or transfer to ICU.

Results

Among the 289 patients included (62.2 ± 17.0 years, 59.2% male), VTE occurred in 49 (17.0%). Padua prediction score for VTE was similar between VTE and non-VTE patients. VTE imaging tests were performed in 100 (34.6%) patients and VTE diagnosed in median 7 (3–11) days after admission. On-admission, time from symptom onset to admission (OR 1.07, CI 95% [1.00–1.16], P = 0.045), Improve score (OR 1.37, [1.02–1.83], P = 0.032), leukocyte count (OR 1.16, [1.06–1.27], P = 0.001) and lack of thromboprophylaxis (OR 27.85, CI 95% [9.35–82.95], P < 0.001) were independent predictors of VTE. The incidence of the composite of death or ICU transfer was 31.0% and more frequent among patients with VTE (47.9% vs. 27.9%, P = 0.01). Fever (OR 5.37, CI 95% [1.44–19.97], P = 0.012), VTE (OR 3.44, CI 95% [1.63–7.25], P = 0.001), lymphopenia (OR 0.32, 95% CI [0.15–0.71]; P = 0.005) and extent of COVID-19 evaluated by chest CT severity (OR 1.56, 95% CI [1.12–2.16]; P = 0.007) were independently associated with in-hospital death or transfer to ICU (Table 1, Fig. 1).

Conclusions

The 17.0% incidence of VTE in non-ICU patients with COVID-19 was associated with worse outcomes. Given the high incidence of VTE in ward patients, there is an urgent need to investigate the optimal anticoagulation regimen.

P2Y12 inhibition by clopidogrel increases adverse clinical outcomes in patients undergoing transcatheter aortic valve replacement

Introduction

Current recommendations support short-term dual antiplatelet therapy (DAPT) for patients undergoing transcatheter aortic valve replacement (TAVR) despite no relevant study exploring the extent of platelet inhibition by clopidogrel.

Purpose

To assess whether P2Y12 inhibition by clopidogrel as evaluated by vasodilator-stimulated phosphoprotein flow cytometry test (VASP-FCT) impacts 1-year clinical outcomes in patients undergoing TAVR.

Methods

Patients were included in a prospective registry between February 2010 and May 2019. VASP-FCT was assessed 24h after the procedure. Responder to clopidogrel was defined by a platelet reactivity index ≤50%.

Results

Of 640 patients who underwent TAVR with preprocedural clopidogrel therapy, we enrolled 491 patients for whom VASP data were available. Responders were identified in 22% (n=110) of patients and low responders were 78% (n=381) of patients. Low body mass index, active cancer, and clopidogrel on admission were found to be independent predictors of responder. Mean transaortic pressure gradient was lower in the responder group at 1-month post-TAVR (9.9±4.4 mmHg vs. 11.2±5.8 mmHg, p=0.03) but was similar at 1-year (11.5±6.2 mmHg vs. 11.9±7.4 mmHg, p=0.74). By multivariate Cox regression analysis, patients responding to clopidogrel (hazard ratio [HR]: 2.19; 95% confidence interval [CI]: 1.04 to 3.64; p=0.04), prior PCI (HR: 2.12; 95% CI: 1.07 to 4.37; p=0.03), and mean transaortic pressure gradient at baseline (HR: 0.07; 95% CI: 0.01 to 0.70; p=0.02) were identified as independent predictors of 1-year adverse clinical outcomes, including all-cause death, myocardial infarction, stroke, and heart failure hospitalization.

Conclusions

Appropriate P2Y12 inhibition by clopidogrel is a major determinant of adverse clinical events after TAVR. In sum, the present data challenges the need of DAPT as a standard therapy during TAVR.

Figure 1

Funding Acknowledgement

Type of funding source: None

Residual inflammation is a major determinant of myocardial recovery and cardiovascular outcome in takotsubo patients

Background

Recent insights have emphasized the importance of myocardial and systemic inflammation in Takotsubo Syndrome (TTS).

Objective

In a large registry of unselected patients, we sought to evaluate whether residual high inflammatory response (RHIR) could impact cardiovascular outcome after TTS.

Methods

Patients with TTS were retrospectively included between 2008 and 2018 in three general hospitals. 385 patients with TTS were split into three subgroups, according to tertiles of C-reactive protein (CRP) levels at discharge (CRP&lt;5.2 mg/l, CRP range 5.2 to 19 mg/l, and CRP&gt;19 mg/L). The primary endpoint was the impact of RHIR, defined as CRP&gt;19 mg/L at discharge, on cardiac death or hospitalization for heart failure.

Results

Follow-up was obtained in 382 patients (99%) after a median of 747 days. RHIR patients were more likely to have a history of cancer or a physical trigger. Left ventricular ejection fraction (LVEF) at admission and at discharge were comparable between groups. By contrast, RHIR was associated with lower LVEF at follow-up (61.7 vs. 60.7 vs. 57.9%; p=0.004) and increased cardiac late mortality (0% vs. 0% vs. 10%; p=0.001). By multivariate Cox regression analysis, RHIR was an independent predictor of cardiac death or hospitalization for heart failure (hazard ratio: 1.97; 95% confidence interval: 1.11 to 3.49; p=0.02).

Conclusions

RHIR was associated with impaired LVEF recovery and was evidenced as an independent factor of cardiovascular events. All together these findings underline RHIR patients as a high-risk subgroup, to target in future clinical trials with specific therapies to attenuate RHIR.

Main results

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): GERCA (Groupe pour l'Enseignement, la prévention et la Recherche Cardiovasculaire en Alsace)

Predictive impact of PVL assessments on clinical outcomes in patients undergoing TAVR

Introduction

Paravalvular leakage (PVL) following transcatheter aortic valve replacement (TAVR) is associated with greater mortality. In clinical practice, determining PVL severity after TAVR remains challenging and often requires multiparametric assessment.

Purpose

This study sought to evaluate the respective value of various modalities of PVL assessments, including transthoracic echocardiography (TTE), cine-angiography, aortic regurgitation index (ARI), and closure time with adenosine diphosphate (CT-ADP), in the prediction of adverse clinical outcomes.

Methods

We included 1044 patients from our prospective TAVR registry between February 2010 and May 2019. Major adverse cardiac and cerebrovascular events (MACCE) was defined as a composite of all-cause death, myocardial infarction, stroke, and heart failure hospitalization within 1-year. Established cutoff values of ARI (&lt;25) and CT-ADP (&gt;180 sec) were used to assess the presence of PVL after TAVR.

Results

Moderate to severe PVL occurred in 14.2% and 5.2% of patients as measured by TTE and angiography. The rate of patients with ARI &lt;25 and CT-ADP &gt;180 sec were 36.5% and 24.9%, respectively. Among the four modalities, PVL evaluated by angiography predicted poorer clinical outcomes (Log rank test; p=0.001), whereas TTE, ARI &lt;25, and CT-ADP &gt;180 sec were not associated with 1-year MACCE. By multivariate Cox regression analysis, moderate to severe PVL by angiography was an independent predictor of 1-year MACCE (hazard ratio: 1.96; 95% confidence interval: 1.22–3.00; p=0.007).

Conclusions

Paravalvular leakage measured by angiography was evidenced as the most meaningful modality in the prediction of adverse clinical outcomes. Future multicenter studies are warranted to ensure these findings in the current TAVR era.

Figure 1

Funding Acknowledgement

Type of funding source: None

Incomplete recovery of takotsubo cardiomyopathy is a major determinant of cardiovascular mortality

Introduction

Although there is an apparent rapid and spontaneous recovery of left ventricular ejection fraction (LVEF) in patients with takotsubo cardiomyopathy, recent studies have demonstrated the long-lasting functional impairment in those patients.

Purpose

We sought to evaluate the predictors of incomplete recovery in chronic phase and its impact on cardiovascular mortality after takotsubo cardiomyopathy.

Methods

Patients with takotsubo cardiomyopathy between 2008 and 2018 were retrospectively enrolled in three different institutions. Takotsubo cardiomyopathy was diagnosed according to the European Society of Cardiology Heart Failure Association criteria. After exclusion of in-hospital deaths, 407 patients were split into 2 subgroups according whether their LVEF were &gt;50% (recovery group; n=333), or ≤50% (incomplete recovery group; n=74) at follow-up. The primary endpoint was the impact of incomplete recovery on cardiovascular mortality.

Results

Patients with incomplete recovery were more likely to be male, to have dementia, pacemaker, and supraventricular arrhythmia. C-reactive protein (CRP) levels on admission, at peak, and at discharge were significantly higher in patients with incomplete recovery. By multivariate logistic regression analysis, lower EF at discharge (odds ratio [OR]: 0.91; 95% confidence interval [CI]: 0.88 to 0.95; p&lt;0.001) and higher CRP levels (OR: 5.56; 95% CI: 1.86 to 16.61; p&lt;0.001) were independent predictors of incomplete recovery at follow-up. The cumulative event-free survival rate according to cardiovascular death was significantly lower in the incomplete recovery group (p&lt;0.001; log-rank test).

Conclusions

We demonstrate that incomplete recovery after takotsubo cardiomyopathy is characterized by a residual systemic inflammation and an increased cardiac mortality at follow-up. Altogether, our findings underline patients with persistent inflammation as a high-risk subgroup, to target in future clinical trials with specific therapies to attenuate inflammation.

Funding Acknowledgement

Type of funding source: None

Collaborative Biosynthesis of Maleimide- and Succinimide-Containing Natural Products by Fungal Polyketide Megasynthases

Fungal polyketide synthases (PKSs) can function collaboratively to synthesize natural products of significant structural diversity. Here we present a new mode of collaboration between a highly reducing PKS (HRPKS) and a PKS-nonribosomal peptide synthetase (PKS-NRPS) in the synthesis of oxaleimides from the Penicillium species. The HRPKS is recruited in the synthesis of an olefin-containing free amino acid, which is activated and incorporated by the adenylation domain of the PKS-NRPS. The precisely positioned olefin from the unnatural amino acid is proposed to facilitate a scaffold rearrangement of the PKS-NRPS product to forge the maleimide and succinimide cores of oxaleimides.

A laser-induced pulsed water jet for layer-selective submucosal dissection of the esophagus

Background and aims: Conventional water jet devices have been used for injecting fluid to lift up lesions during endoscopic submucosal dissection or endoscopic mucosal resection procedures. However, these devices cannot dissect the submucosal layer effectively. Here we aim to elucidate the dissection capability of a laser-induced pulsed water jet and to clarify the mechanism of dissection with layer selectivity. Materials (Subjects) and methods: Pulsed water jets were ejected from a stainless nozzle by accelerating saline using the energy of a pulsed holmium: yttrium-aluminum-garnet laser. The impact force (strength) of the jet was evaluated using a force meter. Injection of the pulsed jet into the submucosal layer was documented by high-speed imaging. The physical properties of the swine esophagus were evaluated by measuring the breaking strength. Submucosal dissection of the swine esophagus was performed and the resection bed was evaluated histologically. Results: Submucosal dissection of the esophagus was accomplished at an impact force of 1.11-1.47 N/pulse (laser energy: 1.1-1.5 J/pulse; standoff distance: 60 mm). Histological specimens showed clear dissection at the submucosal layer without thermal injury. The mean static breaking strength of the submucosa (0.11 ± 0.04 MPa) was significantly lower than that of the mucosa (1.32 ± 0.18 MPa), and propria muscle (1.45 ± 0.16 MPa). Conclusions: The pulsed water jet device showed potential for achieving selective submucosal dissection. It could achieve mucosal, submucosal, and muscle layer selectivity owing to the varied breaking strengths.

A potential pitfall of the modified 12 lead electrocardiogram (Mason-Likar modification) in catheter ablation of idiopathic ventricular arrhythmias originating from the outflow tract

AIMS

The Mason-Likar modified electrocardiogram (ML-ECG) can be interchanged with standard 12 lead ECG electrode positions (standard ECG) without affecting the diagnostic interpretation during sinus rhythm, but the morphological differences during ventricular arrhythmias have not been sufficiently evaluated. This study aimed to elucidate the morphological changes in the ML-ECG precordial leads.

METHODS AND RESULTS

In 53 consecutive patients with premature ventricular contractions predicted to originate from the outflow tract (OT-PVCs), the arrhythmias were analysed by those two ECG methods. The OT-PVC origin sites, which were predicted by currently published criteria with the respective ECG methods prior to catheter ablation, were compared with the successful ablation sites. Compared with the standard-ECG, S-waves in the ML-ECG became shallower in leads V1-4 (P < 0.05 in lead V1; P < 0.001 in leads V2-4), and pseudo-R-waves in lead V1 appeared in seven patients. The precordial leads transition zone shifted counter-clockwise in 18 patients in the ML-ECG. In leads I and aVL, the negative deflection amplitudes of the ML-ECG were greater than those of the standard ECG (P < 0.001), and polarity reversals in lead I appeared in 18 patients. The R-wave amplitudes in all ML-ECG inferior leads were greater than those in the standard-ECG leads (all for P < 0.001). Those changes had an effect on the diagnostic indexes for the localization, and the specificity of the criteria for the ML-ECG was poorer than that for the standard-ECG.

CONCLUSION

Great differences were found between those two ECG methods. Predicting OT-PVC origins by diagnostic criteria with the ML-ECG might result in a misdiagnosis and inefficient ablation.

Re-evaluation of the formalin-ether sedimentation method for the improvement of parasite egg recovery efficiency

The formalin-ether sedimentation (FES) method is considered as reliable method of fecal examination for the detection of parasites. In this study, we re-evaluated several aspects of FES such as (i) pretreatment of feces; (ii) filtration of fecal suspensions; (iii) test-tube material and (iv) substitution of ether by other organic solvents as to see an improvement in parasite egg recovery. The egg count was represented by the number of ova detected per 100 μg of sediment. Pre-treatment of feces with formalin (pH 7) increased egg detection rate remarkably compared with original FES method. Use of three layers of gauze dramatically reduced the sediment in the final product, and led to an increase in the number of ova detected. Use of polypropylene test tubes instead of glass test tubes also increased the number of egg detection. None of the organic solvents used to replace the ether produced better results. Based on these findings, we proposed a modified FES procedure. Further, we also compared the parasite positive rate and the number of ova recovered by using original FES and the modified FES procedures by examining 112 fecal samples collected from school children of parasite endemic area in Nepal. Feces collected from Nepal had many parasite ova, and these fecal samples barely displayed false-negative results even by method with low sensitivity. When the mean number of Hemenolepis nana, hookworm, T. trichiura, and A. lumbricoides ova recovered by original FES and the modified FES methods was compared, the values obtained by modified FES were superior (higher). This result suggested that the modified FES is effective and better for the recovery of parasite ova in areas of low-intensity parasitic infection.

Neonatal hypothyroidism and early undernutrition affect myelin and myelin precursor membranes in a different way

The lipid and protein composition as well as the activity of 2'3' cyclic nucleotide 3' phosphohydrolase (CNPH) and the distribution of individual proteins separated by SDS-PAGE were studied in myelin and in a fraction closely related to myelin or assumed to be a precursor membrane of mature myelin (fraction SN4) isolated from 20-day-old rats made hypothyroid at birth or submitted to early malnutrition. In both experimental conditions lipid and protein components were found to be reduced in myelin when data were expressed as mg/g fresh tissue, but the results were close to those obtained in normal controls when data were expressed as mg/mg total protein of each fraction. CNPH activity was normal in myelin but markedly reduced in fraction SN4. Although the results appear to suggest that both experimental conditions produce a reduction in the amount of myelin but no qualitative changes, the data obtained with SDS-PAGE show that the distribution of the various types of proteins present in this fraction and fraction SN4 was abnormal. Myelin and fraction SN4 isolated from malnourished animals displayed a protein profile which was quite similar to that found in fraction SN4 isolated from normal rats, indicating a delay in the process of myelin maturation. The changes in protein composition of myelin and fraction SN4 produced by neonatal hypothyroidism on the other hand differed clearly from those produced by early malnutrition; the ratio small basic protein: large basic protein (SBP:LBP) was found to be reduced in both membrane fractions in the former condition and the protein patterns of myelin and that of fraction SN4 were different, at variance with what was found in the case of malnourished animals. Our findings appear to suggest that the effects of early malnutrition and neonatal hypothyroidism upon myelin and myelin-related membranes are different, and that myelination is more affected in the latter condition.

Tooth bleaching increases dentinal protease activity

Hydrogen peroxide is an oxidative agent commonly used for dental bleaching procedures. The structural and biochemical responses of enamel, dentin, and pulp tissues to the in vivo bleaching of human (n = 20) premolars were investigated in this study. Atomic force microscopy (AFM) was used to observe enamel nanostructure. The chemical composition of enamel and dentin was analyzed by infrared spectroscopy (FTIR). The enzymatic activities of dental cathepsin B and matrix metalloproteinases (MMPs) were monitored with fluorogenic substrates. The amount of collagen in dentin was measured by emission of collagen autofluorescence with confocal fluorescence microscopy. The presence of Reactive Oxygen Species (ROS) in the pulp was evaluated with a fluorogenic 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) probe. Vital bleaching of teeth significantly altered all tested parameters: AFM images revealed a corrosion of surface enamel nanostructure; FTIR analysis showed a loss of carbonate and proteins from enamel and dentin, along with an increase in the proteolytic activity of cathepsin-B and MMPs; and there was a reduction in the autofluorescence of collagen and an increase in both cathepsin-B activity and ROS in pulp tissues. Together, these results indicate that 35% hydrogen peroxide used in clinical bleaching protocols dramatically alters the structural and biochemical properties of dental hard and soft pulp tissue.

Induction of apoptosis by a potent caffeic acid derivative, caffeic acid undecyl ester, is mediated by mitochondrial damage in NALM-6 human B cell leukemia cells

Caffeic acid esters have various biological activities, and we previously reported that undecyl caffeate (caffeic acid undecyl ester, CAUE), a new caffeic acid derivative, has strong pharmacological activity. The present study investigated the cytotoxicity of both CAUE and its parent compound, caffeic acid phenethyl ester (CAPE), and characterized the mechanisms by which they induce apoptosis in the human B cell leukemia cell line NALM-6. Treatment with CAUE reduced cell survival in NALM-6 cells but had no significant effect on the survival of normal lymphocytes. When assessing the 50% inhibitory concentration (IC(50)) for cytotoxicity, CAUE had 10-fold higher activity than CAPE in NALM-6 cells. CAUE treatment resulted in induction of apoptotic features in NALM-6 cells, including cleaved poly (ADP-ribose) polymerase and activated caspase-3. A caspase inhibitor completely blocked CAUE-induced apoptosis. CAUE treatment resulted in a concentration- and time-dependent decrease in both mitochondrial membrane potential and downregulation of Bcl-2 expression. Moreover, CAUE-induced apoptosis was enhanced in the Bcl-2 knockdown condition induced by small interfering RNA. These data suggest that CAUE-induced apoptosis was mediated via an apoptotic intrinsic pathway including mitochondrial damage and was caspase-dependent. These data also suggest that CAUE is a powerful anti-leukemic agent that acts via induction of apoptosis by mitochondrial damage and selective action in leukemia cells.

Transportation of de novo synthesized jasmonoyl isoleucine in tomato

In plants, jasmonic acid (JA) and its derivatives are thought to be involved in mobile forms of defense against biotic and abiotic stresses. In this study, the distal transport of JA-isoleucine (JA-Ile) that is synthesized de novo in response to leaf wounding in tomato (Solanum lycopersicum) plants was investigated. JA-[¹³C₆]Ile was recovered in distal untreated leaves after wounded leaves were treated with [¹³C₆]Ile. However, as [¹³C₆]Ile was also recovered in the distal untreated leaves, whether JA-Ile was synthesized in the wounded or in the untreated leaves was unclear. Hence, stem exudates were analyzed to obtain more detailed information. When [¹³C₆]Ile and [²H₆]JA were applied separately into the wounds on two different leaves, JA-[¹³C₆]Ile and [²H₆]JA-Ile were detected in the stem exudates but [²H₆]JA-[¹³C₆]Ile was not, indicating that JA was conjugated with Ile in the wounded leaf and that the resulting JA-Ile was then transported into systemic tissues. The [²H₃]JA-Ile that was applied exogenously to the wounded tissues reached distal untreated leaves within 10 min. Additionally, applying [²H₃]JA-Ile to the wounded leaves at concentrations of 10 and 60 nmol/two leaves induced the accumulation of PIN II, LAP A, and JAZ3 mRNA in the distal untreated leaves of the spr2 mutant S. lycopersicum plants. These results demonstrate the transportation of de novo synthesized JA-Ile and suggest that JA-Ile may be a mobile signal.

Phylogenetic groups and cephalosporin resistance genes of Escherichia coli from diseased food-producing animals in Japan

A total of 318 Escherichia coli isolates obtained from different food-producing animals affected with colibacillosis between 2001 and 2006 were subjected to phylogenetic analysis: 72 bovine isolates, 89 poultry isolates and 157 porcine isolates. Overall, the phylogenetic group A was predominant in isolates from cattle (36/72, 50%) and pigs (101/157, 64.3%) whereas groups A (44/89, 49.4%) and D (40/89, 44.9%) were predominant in isolates from poultry. In addition, group B2 was not found among diseased food-producing animals except for a poultry isolate. Thus, the phylogenetic group distribution of E. coli from diseased animals was different by animal species. Among the 318 isolates, cefazolin resistance (minimum inhibitory concentrations: ≥32 μg/ml) was found in six bovine isolates, 29 poultry isolates and three porcine isolates. Of them, 11 isolates (nine from poultry and two from cattle) produced extended spectrum β-lactamase (ESBL). The two bovine isolates produced bla_CTX-M-2, while the nine poultry isolates produced bla_CTX-M-25 (4), bla_SHV-2 (3), bla_CTX-M-15 (1) and bla_CTX-M-2 (1). Thus, our results showed that several types of ESBL were identified and three types of β-lactamase (SHV-2, CTX-M-25 and CTX-M-15) were observed for the first time in E. coli from diseased animals in Japan.

Glucagon-like peptide-1 receptor agonist ameliorates renal injury through its anti-inflammatory action without lowering blood glucose level in a rat model of type 1 diabetes

AIMS/HYPOTHESIS

Glucagon-like peptide-1 (GLP-1) has various extra-pancreatic actions, in addition to its enhancement of insulin secretion from pancreatic beta cells. The GLP-1 receptor is produced in kidney tissue. However, the direct effect of GLP-1 on diabetic nephropathy remains unclear. Here we demonstrate that a GLP-1 receptor agonist, exendin-4, exerts renoprotective effects through its anti-inflammatory action via the GLP-1 receptor without lowering blood glucose.

METHODS

We administered exendin-4 at 10 μg/kg body weight daily for 8 weeks to a streptozotocin-induced rat model of type 1 diabetes and evaluated their urinary albumin excretion, metabolic data, histology and morphometry. We also examined the direct effects of exendin-4 on glomerular endothelial cells and macrophages in vitro.

RESULTS

Exendin-4 ameliorated albuminuria, glomerular hyperfiltration, glomerular hypertrophy and mesangial matrix expansion in the diabetic rats without changing blood pressure or body weight. Exendin-4 also prevented macrophage infiltration, and decreased protein levels of intercellular adhesion molecule-1 (ICAM-1) and type IV collagen, as well as decreasing oxidative stress and nuclear factor-κB activation in kidney tissue. In addition, we found that the GLP-1 receptor was produced on monocytes/macrophages and glomerular endothelial cells. We demonstrated that in vitro exendin-4 acted directly on the GLP-1 receptor, and attenuated release of pro-inflammatory cytokines from macrophages and ICAM-1 production on glomerular endothelial cells.

CONCLUSIONS/INTERPRETATION

These results indicate that GLP-1 receptor agonists may prevent disease progression in the early stage of diabetic nephropathy through direct effects on the GLP-1 receptor in kidney tissue.

Distal transport of exogenously applied jasmonoyl-isoleucine with wounding stress

Determining the mobile signal used by plants to defend against biotic and abiotic stresses has proved elusive, but jasmonic acid (JA) and its derivatives appear to be involved. Using deuterium-labeled analogs, we investigated the distal transport of JA and jasmonoyl-isoleucine (JA-Ile) in response to leaf wounding in tobacco (Nicotiana tabacum) and tomato (Solanum lycopersicum) plants. We recovered [(2)H(2)-2]JA ([(2)H(2)]JA) and [(2)H(3)-12]JA-Ile ([(2)H(3)]JA-Ile) in distal leaves of N. tabacum and S. lycopersicum after treating wounded leaves with [(2)H(2)]JA or [(2)H(3)]JA-Ile. We found that JA-Ile had a greater mobility than JA, despite its lower polarity, and that application of exogenous JA-Ile to wounded leaves of N. tabacum led to a higher accumulation of JA and JA-Ile in distal leaves compared with wounded control plants. We also found that exudates from the stem of S. lycopersicum plants with damaged leaflets contained JA and JA-Ile at higher levels than in an undamaged plant, and a significant difference in the levels of JA-Ile was observed 30 min after wounding. Based on these results, it was found that JA-Ile is a transportable compound, which suggests that JA-Ile is a signaling cue involved in the resistance to biotic and abiotic stresses in plants.

Epidemiology of plasmid-mediated quinolone resistance in salmonella enterica serovar typhimurium isolates from food-producing animals in Japan

A total of 225 isolates of Salmonella enterica serovar Typhimurium from food-producing animals collected between 2003 and 2007 were examined for the prevalence of plasmid-mediated quinolone resistance (PMQR) determinants, namely qnrA, qnrB, qnrC, qnrD, qnrS, qepA and aac(6')Ib-cr, in Japan. Two isolates (0.8%) of S. Typhimurium DT104 from different dairy cows on a single farm in 2006 and 2007 were found to have qnrS1 on a plasmid of approximately 9.6-kbp. None of the S. Typhimurium isolates had qnrA, qnrB, qnrC, qnrD, qepA and acc(6')-Ib-cr. Currently in Japan, the prevalence of the PMQR genes among S. Typhimurium isolates from food animals may remain low or restricted. The PFGE profile of two S. Typhimurium DT104 isolates without qnrS1 on the farm in 2005 had an identical PFGE profile to those of two S. Typhimurium DT104 isolates with qnrS1. The PFGE analysis suggested that the already existing S. Typhimurium DT104 on the farm fortuitously acquired the qnrS1 plasmid.

Test Medium for the Growth of Nitrosomonas europaea

A mineral medium for studying the growth of Nitrosomonas europaea was developed and examined. The medium was defined in terms of chemical speciation by using chemical equilibrium computer models. The medium significantly increased the metabolic activity of the organisms compared with previously developed media, yielding a specific growth rate as high as 3.0 day (generation time, 5.5 h). The specific growth rate was enhanced by increasing the inoculum and was linearly correlated with the inoculum-to-total-culture volume ratio on a semilog scale. A reproducible growth rate for N. europaea was obtained with this medium under controlled experimental conditions.

A novel double mutation in FUS gene causing sporadic ALS

It has been shown that mutations in the Fused in Sarcoma gene (FUS) could explain up to 5% of cases with familial amyotrophic lateral sclerosis (ALS). Our mutation analysis of FUS in a Canadian ALS patient of Chinese origin revealed an unusual novel heterozygous double point mutation (R514S/E516V) confirming that exon 15 is a mutation hot-spot. The substitutions are in cis position to each other and affect highly conserved codons in the RGG-rich region of the FUS protein. The absence of clinical signs of ALS in the relatives of the affected carrier could indicate that this mutation is incompletely penetrant or de novo. The pathologic significance of the R514S/E516V mutation was confirmed by immunohistochemistry. FUS-positive cytoplasmic inclusions were noted in a moderate number in neurons and abundantly in glial cells in the motor cortex and the brainstem. Of interest, a significant number of neuronal and glial FUS-positive inclusions were found in the tegmentum of the brainstem. Importantly, some neurons with inclusions showed retention of the normal nuclear FUS immunostaining.

Stimulation of neuronal neurite outgrowth using functionalized carbon nanotubes

Low concentrations (0.11-1.7 microg ml(-1)) of functionalized carbon nanotubes (CNTs), which are multi-walled CNTs modified by amino groups, when added with nerve growth factor (NGF), promoted outgrowth of neuronal neurites in dorsal root ganglion (DRG) neurons and rat pheochromocytoma cell line PC12h cells in culture media. The quantity of active extracellular signal-regulated kinase (ERK) was higher after the addition of both 0.85 microg ml(-1) CNTs and NGF than that with NGF alone. CNTs increased the number of cells with neurite outgrowth in DRG neurons and PC12h cells after the inhibition of the ERK signaling pathway using a mitogen-activated protein kinase (MAPK)/ERK kinase (MEK) inhibitor. Active ERK proteins were detected in MEK inhibitor-treated neurons after the addition of CNTs to the culture medium. These results demonstrate that CNTs may stimulate neurite outgrowth by activation of the ERK signaling pathway. Thus, CNTs are biocompatible and are promising candidates for biological applications and devices.