Interpreting SVM for medical images using Quadtree

In this paper, we propose a quadtree based approach to capture the spatial information of medical images for explaining nonlinear SVM prediction. In medical image classification, interpretability becomes important to understand why the adopted model works. Explaining an SVM prediction is difficult due to implicit mapping done in kernel classification is uninformative about the position of data points in the feature space and the nature of the separating hyperplane in the original space. The proposed method finds ROIs which contain the discriminative regions behind the prediction. Localization of the discriminative region in small boxes can help in interpreting the prediction by SVM. Quadtree decomposition is applied recursively before applying SVMs on sub images and model identified ROIs are highlighted. Pictorial results of experiments on various medical image datasets prove the effectiveness of this approach. We validate the correctness of our method by applying occlusion methods.

Expression of MTNR1A, steroid (ERα, ERβ, and PR) receptor gene transcripts, and the concentration of melatonin and steroid hormones in the ovarian follicles of buffalo

High ambient temperature exhibits a retrograde effect on buffalo reproduction because of heat stress. Moreover, melatonin is known to regulate reproductive changes in seasonally reproductive animals by binding to high affinity, G protein-coupled receptors. The MTNR1A gene is a prime receptor, mediating the effect of melatonin at the neuroendocrine level to control seasonal reproduction. In sheep, the role of melatonin is well known; however, studies have not been conducted in buffalo to determine its effect during favorable and unfavorable breeding seasons. Therefore, the present study aimed to (1) determine the expression of MTNR1A, ERα, ERβ, and PR gene transcripts in the ovarian follicles of buffalo during the summer and winter seasons and (2) analyze melatonin, 17β-estradiol, and progesterone concentrations in the follicular fluid of buffalo during both seasons. Murrah buffalo ovaries were collected during both the summer (May-June) and winter (December-January) seasons. All visible ovarian follicles were allocated into one of three groups: (1) small (8-9.9 mm); (2) medium (10-11.9 mm); and (3) large (12-14 mm). Follicular fluid was aspirated from each group of follicles for hormone analyses. The granulosa cells were processed for RNA extraction. Furthermore, they were subjected to real-time quantitative PCR to analyze the expression (relative quantification) of MTNR1A, ERα, ERβ, and PR in each follicular group. The expression of MTNR1A gene transcript decreased with the increasing size of the follicle and intrafollicular melatonin concentration. Expression of ERα and PR remained unaffected by the season and was similar (P > 0.05) in all groups. Expression of ERβ was higher (P < 0.05) in summer than winter; nevertheless, small-sized follicles from the summer exhibited higher (P < 0.05) expressions than medium- and large-sized follicles. The overall intrafollicular melatonin concentration was positively correlated (P < 0.05) with 17β-estradiol and progesterone concentrations. In conclusion, the decreased expression of MTNR1A and increased concentration of intrafollicular melatonin with the increasing size of the follicle indicates a probable role in folliculogenesis and ovulation in buffalo.

P1409Effectiveness of atrial fibrillation ablation using a contact force stability module with contact force or non-contact force catheter

Funding Acknowledgements

This study was funded by Biosense Webster, Inc.

Background

Catheter ablation is a mainstream treatment option for atrial fibrillation (AF). Recently, contact force (CF) enabled ablation catheters and a stability module were developed to allow for real-time CF sensing and improvement of catheter-tissue stability, which is important for achieving an optimal clinical outcome.  We assessed the relative effectiveness of these new technologies, as well as the optimal CF stability parameters, in a real-world setting.

Purpose

To compare the clinical effectiveness of AF ablations performed with a CF catheter using location stability settings of 2.5 mm maximum distance for 12 s minimum (2.5/12) vs. a non-CF catheter with settings of 3 mm for 7 s (3/7).

Methods

Within 1/14–4/18, 176 de novo AF ablations using either a CF catheter with stability settings of 2.5/12 (n = 92, 5/16–4/18) or a non-CF catheter with stability settings of 3/7 (n = 84, 1/14–3/14) were performed by a single operator at a Canadian medical center. Patients routinely wore 48 hour Holter monitors every three months through the first year. The primary measures of effectiveness were Kaplan-Meier (KM) survival estimates of freedom from AF/atrial tachycardia (AT)/atrial flutter (AFL) recurrence after a 3-month blanking period and reablation.

Results

The CF group was 62.9 ± 10.0 years old, 57.6% male, and 66.3% paroxysmal (PAF). The non-CF group was 61.6 ± 9.9 years old, 63.1% male, and 76.2% PAF. Procedural complications consisted of a single vascular access complication in the non-CF group. The 12-month estimate of freedom from AF/AT/AFL recurrence was 79.4% in the CF group vs. 64.8% in the non-CF group (p = 0.058 for difference in survival over time). 12-month freedom from reablation was 90.4% in the CF group vs. 70.5% in the non-CF group (p = 0.002).

Conclusion

CF ablation with more stringent stability settings of 2.5/12 was more effective than non-CF ablation with stability settings of 3/7, likely attributable to the CF catheter enabling visualization of catheter-tissue contact and the stability module facilitating maintenance of CF stability during ablation.

Abstract Figure.

Effect of yoga practices on general mental ability in urban residential school children

Introduction Mental ability of children represents functioning of brain in different aspects of competency including verbal, mathematical, logical reasoning and spatial, which is of prime importance for academic performance. Objective The objective of this study was to assess the effect of yoga on general mental ability of urban residential school children. Methods Sixty-six urban school children aged 11-15 years were selected as participants. All the selected participants were staying in a residential school in Pune District. A stratified random sampling method was used to divide the students into experimental and control groups. There were 32 students in experimental group and 29 students in control group. Both experimental and control groups were assessed for general mental ability by using standard questionnaire at the baseline and at the end of 12 weeks of yoga training. The study participants of experimental group underwent yoga training for 12 weeks, for 1 h in the morning for a period of 12 weeks. The control group did not undergo any yoga training during this time period. Results The experimental group participants showed significant improvement in general mental ability as compared to control group. Conclusion The findings of this study indicate that yoga practices could improve general mental ability of urban residential school children.

Thermionic microwave gun for terahertz and synchrotron light sources

Conventional thermionic microwave and radio frequency (RF) guns can offer high average beam current, which is important for synchrotron light and terahertz (THz) radiation source facilities, as well as for industrial applications. For example, the Advanced Photon Source at Argonne National Laboratory is a national synchrotron-radiation light source research facility that utilizes thermionic RF guns. However, these existing thermionic guns are bulky, difficult to handle and install, easily detuned, very sensitive to thermal expansion, and due for a major upgrade and replacement. In this paper, we present the design of a new, more stable, and reliable gun with optimized electromagnetic performance, improved thermal engineering, and a more robust cathode mounting technique, which is a critical step to improve the performance of existing and future light sources, industrial accelerators, and electron beam-driven THz sources. We will also present a fabricated gun prototype and show results of high-power and beam tests.

In Vitro Antidiabetic Effect of Neohesperidin

Objective: The present study was performed to determine in vitro antidiabetic effect of neohesperidin. To evaluate inhibitory effect of neohesperidin on α-amylase and α-glucosidase diabetes causing enzyme. Methods and Materials: Invitro carbohydrate metabolizing enzyme based inhibitory methods were used to determine antidiabetic effect of neohesperidin. Alpha (α)-amylase inhibitory assay was performed using different sources i.e. wheat alpha (α)-amylase enzyme, salivary alpha (α)-amylase and fungal alpha (α)-amylase assay. Alpha (α)-glucosidase inhibitory assay was performed using alpha (α)-glucosidase (B. stearothermophil), alpha (α)-glucosidase rat intestine and alpha (α)-glucosidase from baker’s yeast. Sucrase inhibitory assay from rat small intestine. Result: Neohesperidin possess a potent anti-diabetic by significantly inhibiting alpha amylase activity. Conclusion: It was concluded that enzyme inhibitory activity of neohesperidin shown a significantly higher inhibitory activity on alpha-amylase in comparision to alpha-glucosidase & Sucrase enzymes. Keywords: Neohespiridin, acarbose, alpha-amylase, alpha-glucosidase

Measuring health and well-being with the help of the community

Issue

The Well North Programme is a multi-centre study focused on reducing inequalities in deprived communities through locally-led interventions and activities. As a locally driven project where the local stakeholders were involved in the programme of work, it was important to involve the community when deciding what to measure.

Description

As part of the evaluation there was a need to produce a tool to capture health and wellbeing information that was relevant to the specific communities involved in the project. In order to do this, we established that we needed local people to define what they wanted to measure, and we would use evidence synthesis techniques to identify tools that could be used to measure it within the community.

Results

We formulated the Well North Star, a bespoke spider diagram designed to capture individual level data. The Star is a quantitative tool used to collect individual-level data at an individual, organisational and geographical level. Each arm of the star represents an important theme, selected for measurement by local people. Identified local stakeholders (including residents, voluntary sector, police and councillors) were invited to workshops in order to decide what issues were important locally. After group discussions and thematic analysis, up to seven issues were highlighted as the most important in the community. Two of the main issues highlighted within local communities were aspiration and access to local information. After extensive literature search, tools to measure these were insufficient (e.g. aspiration tools focused on aspiration to become famous) and so bespoke tools needed to be created.

Lessons

When conducting community driven research, it is important to involve representatives from the community in identifying issues that are important to them. There is a gap between what academics and researchers consider important in local communities and what the communities themselves consider important.

1207Pulsed Field Ablation: Acute and Chronic Safety and Lesion Efficacy

Introduction

Thermal ablation methods are the cornerstone of treatment for atrial fibrillation. However, they pose a risk to extra-cardiac structures and may result in inadequate efficacy. Nonthermal, pulsed-field ablation (PFA) delivery to cardiac tissues may create durable, efficacious lesions while avoiding collateral damage.

Purpose

The purpose of this preclinical GLP study was to assess acute and chronic electrical isolation combined with a pathology assessment of chronic lesion extent in response to PFA delivery to cardiac tissue, and to document any collateral damage.

Methods

Six pigs were treated with biphasic, bipolar PFA doses through a circular multi-electrode catheter. PFA was delivered at four locations at specified voltages: superior vena cava (SVC at 700V), right atrial appendage (RAA at 1500V), left atrial appendage (LAA at 1200V), and right pulmonary vein (RPV at 1500V). Phrenic nerve pacing thresholds and electrical block at SVC, RPV, and RAA sites were investigated acutely, and electrical block at the SVC sites chronically. Pigs were survived for 4 weeks. After euthanasia, necropsies and histopathological assessments documented the findings at the lesion sites and collateral tissues.

Results

Post PFA, entrance block was achieved in all SVC, RPV, and RAA sites. Histopathology showed characteristic replacement fibrosis of the myocardium at all ablation sites. The PFA lesions in the SVC and RPV were all continuously circumferential and histopathology did not detect any remaining myofiber conduits across the post-ablation fibrosis (consistent with the electrical assessments). PFA of the appendages caused wide-ranging fibrosis in the RAA, and limited fibrosis in the LAA. Histologically, the atrial fibrosis was almost exclusively transmural in both, with the RAA lesions overall diagnosed as circumferentially complete in all but one case. The right phrenic nerve (RPN) pacing thresholds were unchanged from baseline to the end of the procedure and were all <1.0V. The examined juxtaposed RPN segments exposed to PFA at the SVC and RPV sites were normal. None of the ablated targets was associated with stenosis, aneurysms, luminal thrombus or collateral damage on the abluminal side.

Continuous lesion sites

Conclusions

This limited preclinical study evaluated the acute and chronic safety and efficacy of PFA in multiple cardiac and vascular treatment sites. In this porcine model, PFA results in acute and chronic electrical isolation, confirmed by pathology data, for all of the RPV and SVC targets. Pathology findings of the RAA revealed the ability to achieve chronic transmural lesions in highly trabeculated cardiac tissue. No collateral damage was seen to the adjacent RPN.

Acknowledgement/Funding

Medtronic

P3753Does empagliflozin modulate the autonomic system among patients with type 2 diabetes and coronary artery disease? Insights from the Holter sub-study of the EMPA-Heart CardioLink-6 Randomised Trial

Introduction

The mechanism behind how empagliflozin, a sodium-glucose co-transporter 2 (SGLT2) inhibitor, reduces all-cause and cardiovascular mortality among patients with type 2 diabetes (T2DM) and coronary artery disease (CAD) is unknown. Autonomic tone, as reflected by changes in heart rate variability (HRV), is an established prognosticator in patients with CAD and/or heart failure.

Purpose

To assess if empagliflozin treatment changes HRV in subjects with T2DM and CAD.

Methods

In the double-blind EMPA-Heart trial, 97 subjects with T2DM and CAD were randomised to empagliflozin 10 mg/day or placebo for 6 months and underwent 24-hour Holter monitoring at baseline and 6 months. Using automated algorithms, time and frequency HRV domain measures were obtained (standard deviation of NN intervals (SDNN); SD of the average NN intervals for each 5-minute segment (SDANN); root mean square of successive RR interval differences (rMSSD); % interval differences of successive NN intervals >50 ms (pNN50); ratio of low to high frequency (LF/HF)). Changes of these HRV parameters were calculated over 6 months. Between-group differences in HRV parameters were compared using ANCOVA.

Results

Complete Holter data (baseline and 6-month) were available for 68% (n=66) of the cohort. The average heart rate (HR) at baseline/6 months was 69.5±9.8 bpm/72.8±8.1 bpm and 76±10.4 bpm/76.5±10.6 in the placebo group and empagliflozin group, respectively. Both groups had similar changes in average HR over 6 months. Key Holter data are summarised in the table. SDNN and SDANN were higher in the placebo vs. empagliflozin group at 6 months; no significant difference was noted for all other measures.

Empagliflozin 10 mg/day (n=33) Placebo (n=33) Adjusted difference between Empagliflozin and Placebo (ANCOVA) Baseline, Mean (SD) 6-month, Mean (SD) Baseline, Mean (SD) 6-month, Mean (SD) Mean, (95% CI) P-value SDNN (ms) 100.49 (43.74) 98.05 (38.86) 109.35 (30.02) 125.08 (43.83) −18.55 (−34.28, −2.82) 0.022 SDANN (ms) 86.84 (39.34) 83.76 (35.53) 94.70 (28.52) 118.28 (77.41) −20.24 (−37.27, −3.21) 0.021 rMSSD (ms) 27.00 (11.84) 27.22 (13.48) 28.00 (11.58) 27.17 (9.38) −1.23 (−6.02, 3.55) 0.608 pNN50 (%) 7.81 (7.59) 8.32 (9.51) 8.26 (7.8) 6.93 (5.35) 0.51 (−2.61, 3.62) 0.746 LF/HF ratio 1.63 (0.52) 1.65 (0.51) 1.53 (0.43) 1.83 (0.82) −0.08 (−0.38, 0.22) 0.602

Conclusions

Among subjects with T2DM and CAD, changes in HRV over 6 months were similar in the empagliflozin and placebo arms suggesting that the mortality benefit conferred by empagliflozin is not associated with positive modulation of autonomic tone.

Acknowledgement/Funding

This trial was supported by an unrestricted investigator-initiated study grant from Boehringer Ingelheim.

Vitamins for Cancer Prevention and Treatment: An Insight

Over a few decades a strong interlink between oxidative damage and cancer has been investigated by various scientists across the world on the basis of epidemiological observations of the effects of fruits and vegetables used in the diet for cancer patients. Primarily, Vitamin C, Vitamin D and Vitamin E are reported to be involved in the amelioration of side effects which occur in chemotherapy and radiation therapy of lungs, stomach, prostate, colorectal, gastric head and neck cancers. The vitamins acting as antioxidant adjuvants are found to have apoptotic and antiangiogenesis potential as well as inhibitory effects against metastasis in cancer cells. This chapter explicitly discusses the key aspects concerned with the vitamins in relation to cancer prevention and treatment. It describes vitamins and their natural resources, role of vitamins in the body, and vitamins as prime ingredients in the diet and their effects on cancer biology with reference to recent research reports. Moreover, this paper also includes the emerging potential of pharmaceutical advances to enhance bioavailability of the vitamins to cancer patients with improved safety and efficacy. Clinicians and researchers must mull over the nutritional requirements of individual cancer patient so as to treat cancer and increase life expectancy.

Oxygen mediated highly efficient cobalt(ii) porphyrin-catalyzed reduction of functional chromones: experimental and computational studies

The highly efficient oxygen mediated reduction of functional chromones with sodium borohydride (NaBH₄) catalyzed by cobalt(ii) porphyrins afforded biologically active chroman-4-ols as the reduction products in 80–98% yields.