Reducing Salivary Toxicity with Adaptive Radiotherapy (ReSTART): A Randomized Controlled Trial Comparing Conventional IMRT to Adaptive IMRT in Head and Neck Squamous Cell Carcinomas

BACKGROUND

The utility of Adaptive Radiotherapy (ART) in Head and Neck Squamous Cell Carcinoma (HNSCC) remains to be ascertained. While multiple retrospective and single-arm prospective studies have demonstrated its efficacy in decreasing parotid doses and reducing xerostomia, adequate randomized evidence is lacking.

METHODS AND ANALYSIS

ReSTART (Reducing Salivary Toxicity with Adaptive Radiotherapy) is an ongoing phase III randomized trial of patients with previously untreated, locally advanced HNSCC of the oropharynx, larynx, and hypopharynx. Patients are randomized in a 1:1 ratio to the standard Intensity Modulated Radiotherapy (IMRT) arm {Planning Target Volume (PTV) margin 5 mm} vs. Adaptive Radiotherapy arm (standard IMRT with a PTV margin 3 mm, two planned adaptive planning at 10th and 20th fractions). The stratification factors include the primary site and nodal stage. The RT dose prescribed is 66Gy in 30 fractions for high-risk PTV and 54Gy in 30 fractions for low-risk PTV over six weeks, along with concurrent chemotherapy. The primary endpoint is to compare salivary toxicity between arms using salivary scintigraphy 12 months' post-radiation. To detect a 25% improvement in the primary endpoint at 12 months in the ART arm with a two-sided 5% alpha value and a power of 80% (and 10% attrition ratio), a sample size of 130 patients is required (65 patients in each arm). The secondary endpoints include acute and late toxicities, locoregional control, disease-free survival, overall survival, quality of life, and xerostomia scores between the two arms.

DISCUSSION

The ReSTART trial aims to answer an important question in Radiation Therapy for HNSCC, particularly in a resource-limited setting. The uniqueness of this trial, compared to other ongoing randomized trials, includes the PTV margins and the xerostomia assessment by scintigraphy at 12 months as the primary endpoint.

Biomedical waste plastic: bacteria, disinfection and recycling technologies-a comprehensive review

Plastic recycling reduces the wastage of potentially useful materials as well as the consumption of virgin materials, thereby lowering the energy consumption, air pollution by incineration, soil and water pollution by landfilling. Plastics used in the biomedical sector have played a significant role. Reducing the transmission of the virus while protecting the human life in particular the frontline workers. Enormous volumes of plastics in biomedical waste have been observed during the outbreak of the pandemic COVID-19. This has resulted from the extensive use of personal protective equipment such as masks, gloves, face shields, bottles, sanitizers, gowns, and other medical plastics which has created challenges to the existing waste management system in the developing countries. The current review focuses on the biomedical waste and its classification, disinfection, and recycling technology of different types of plastics waste generated in the sector and their corresponding approaches toward end-of-life option and value addition. This review provides a broader overview of the process to reduce the volume of plastics from biomedical waste directly entering the landfill while providing a knowledge step toward the conversion of "waste" to "wealth." An average of 25% of the recyclable plastics are present in biomedical waste. All the processes discussed in this article accounts for cleaner techniques and a sustainable approach to the treatment of biomedical waste.

Graphical abstract

Function Preservation With Brachytherapy: Reviving the Art. Improving Quality of Life With Brachytherapy for Urological Malignancies

Brachytherapy for localised prostate, muscle-invasive bladder and penile cancer is well established, providing high tumour dose delivery and minimising normal tissue doses compared with external beam techniques. In prostate cancer, the main impact on quality of life relates to diminished sexual function and irritative or obstructive urinary symptoms, which are seen up to 15 years after treatment. Significant changes in bowel function are rare. Compared with radical prostatectomy or external beam radiotherapy, irritative or obstructive urinary symptoms are more prominent, whereas incontinence is less than after radical prostatectomy and bowel changes are less than after external beam radiotherapy. For muscle-invasive bladder cancer, when compared with radical cystectomy, although no difference is seen for urinary symptoms or fatigue, role and social functioning scores are higher and there is better post-treatment sexual function in both men and women. Compared with surgical treatment for penile cancer, brachytherapy results in better erectile function scores than after glansectomy and partial penectomy and high quality of life scores, with good satisfaction ratings for cosmetic appearance.

P-795 Comparison of intra-ovarian platelet rich plasma versus autologous bone marrow derived stem cell instillation in women with diminished ovarian reserve for ovarian rejuvenation

Study question

To compare role of intra-ovarian platelet rich plasma (PRP) versus marrow derived stem cell (SC) instillation for improvement in ovarian reserve (AFC, AMH and FSH)

Summary answer

Both PRP and SC therapy improves the ovarian reserve however, response to PRP is superior to SC post intervention

What is known already

With increasing incidence of females with diminished ovarian reserve (DOR), posing a serious challenge in terms of limited treatment options for these couples. Clinicians are trying to find effective strategies besides oocyte donation or adoption Of late, novel ovarian rejuvenation approaches has been investigated which are currently available for research purposes only. Multiple studies are evaluating effect of intra-ovarian PRP or autologous SC instillation, the results are encouraging as they are showing improvement in ovarian reserve thus bringing a paradigm shift in treatment options. None of the published studies so far have compared PRP versus SC in DOR population.

Study design, size, duration

A prospective comparative study was conducted at Division of Reproductive Medicine of a tertiary care institute. 72 infertile females (20-39 years) with poor ovarian reserve (AMH <1.2 ng /ml; AFC<5) were enrolled in the study between January 2020 to December 2021. The two comparative groups underwent either intra-ovarian PRP instillation (n = 42) or autologous SC transplantation (n = 30).

Participants/materials, setting, methods

After the two groups were matched (PRP vs SC) for baseline characteristics (Age, AMH, AFC, FSH, Estradiol), 30 subjects in each group were compared for change in serum FSH/AMH/Estradiol levels, AFC, right and left ovarian volume at 1st month and 3rd month post intervention from the baseline. This was also compared between the two groups using Student t-test. The cost and procedural pain measured using Visual analog scale (VAS) were also compared between the groups.

Main results and the role of chance

After matching for baseline characteristics, significant ∼ 1.8/2 and ∼1.5/1.6 fold increase in AFC at 1st/3rd month post intervention (p<0.001) was observed after PRP instillation and SC transplantation respectively. This significant improvement was observed more in PRP group than SC group at 3rd month post intervention (7.07 vs 5.60, p=0.02), while no significant difference existed at 1st month of follow up. However, there was no significant improvement in serum FSH, AMH and Estradiol levels (p0.05) from the baseline at 1st and 3rd month post intervention in both the groups. Similarly, there was no significant difference between the two groups in serum FSH level (7.98 IU/ml vs 9.62 IU/ml, p=0.062; 8.26 IU/ml vs 9.50 IU/ml, p=0.15), AMH level (1.62 ng/ml vs 1.02 ng/ml, p=0.27; 1.35 ng/ml vs 0.95 ng/ml, p=0.24), Estradiol level (49.12 pg/ml vs 56.48 pg/ml p=0.443; 54.7 pg/ml vs 61.12 pg/ml, p=0.44), right ovarian volume (3.13 cm3 vs 2.49 cm3, p=0.06; 3.37 cm3 vs 2.74 cm3,p=0.063) and left ovarian volume (2.98 cm3 vs 2.47 cm3, p=0.102; 2.87 cm3 vs 2.34 cm3,p=0.103) at 1st and 3rd month post intervention respectively. PRP was more cost-effective and associated with less pain (32.5 mm vs 28.13 mm, p=0.02), and better patient compliance.

Limitations, reasons for caution

This was a comparative study and the participants were not randomized but were matched for the baseline characteristics. Also due to impact of Covid-19 causing intermittent pause in nonessential facilities like IVF services, a smaller sample size could be enrolled and also clinical outcomes could not be evaluated

Wider implications of the findings

This study, although comparative, for the first time highlights the beneficial role of PRP over SC, thus can establish superiority of PRP as minimally invasive, economical, patient friendly and a recommended therapy for ovarian rejuvenation and folliculogenesis, providing the DOR females an opportunity to produce their own offspring.

Trial registration number

CTRI/2020/01/022726

P94 LOWER RATE OF MAJOR BLEEDING IN HIGH–RISK PATIENTS UNDERGOING LEFT ATRIAL APPENDAGE OCCLUSION: A PROPENSITY MATCHED COMPARISON WITH DIRECT ORAL ANTICOAGULATION

Background

Stroke prophylaxis in very high risk (CHA2DS2–VASc ≥ 5) patients with atrial fibrillation (AF) is one of the major challenges faced by physicians. Specifically, initiating direct oral anticoagulants (DOACs) in these patients poses a therapeutic conundrum due to the concomitant high risk of bleeding. Left atrial appendage occlusion (LAAO) might be a potential alternative for thromboembolic (TE) prevention; however, there are no studies comparing these two strategies in very high–risk patients.

Objective

To evaluate the efficacy of LAAO versus DOACs in AF patients at very high TE risk.

Methods

Data were extracted from two prospective databases including 1053 Watchman and 1328 DOAC patients. Watchman patients with a CHA2DS2–VASc ≥ 5 accounted for 26.3% (n = 277). In order to attenuate the imbalance in covariates, a 1:1 propensity score matching technique was used (co–variates: age, sex, CHA2DS2–VASc and HAS–BLED scores). This method resulted in 554 matched patients (277 patients per group; mean age: 79±7y; 57.4% F; CHA2DS2–VASc: 5.8±0.9). The primary endpoint was a composite of cardiovascular (CV) death, TE events (Stroke/TIA/peripheral embolism) and clinically significant bleeding. The annual TE and major bleeding risks were estimated based on the CHA2DS2–VASc score and compared with the annualized observed risk.

Results

After a mean follow–up of 26±7 months, total events were 55 (9.4 event rates per 100 patient–years) in LAAO group vs. 78 (14.9 event rates per 100 patient–years) in DOAC group. DOACs had a significantly higher risk of the primary endpoint (hazard ratio [HR]: 1.30; 95% confidence interval [CI]: 1.08 to 1.56; p = 0.03). TE events (HR: 1.15; 95% CI: 0.84 to 1.57; p = 0.63) and CV death (HR: 1.13; 95% CI: 0.84 to 1.54; p = 0.63) did not differ between groups. Major bleeding events were significantly lower in LAAO patients (HR: 0.75; 95% CI: 0.51 to 0.82; p = 0.04). The unadjusted estimated risk of TE events was 12.3% with LAAO and 12.4% with DOACs. The annualized incidence of TE was 3.2% with LAAO and 4.1% with DOACs, which led to a risk reduction of 74% and 67%, respectively.

Conclusion

In a large cohort of AF patients at very high TE risk (CHA2DS2–VASc ≥ 5), LAAO showed similar stroke prevention but a significantly lower risk of major bleeding than DOACs during a > 2year follow–up.

C32 TRANSCATHETER LEAK OCCLUSION WITH ENDOVASCULAR COILS FOLLOWING LEFT ATRIAL APPENDAGE CLOSURE: PROCEDURAL SUCCESS AND OUTCOMES BEFORE AND AFTER LEAK CLOSURE

Background

Whether residual peri–device leaks after left atrial appendage occlusion (LAAO) portend a higher risk of thromboembolism (TE), it is still a matter of debate.

Objectives

We report the TE risk in patients with incomplete LAA closure before and after leak closure with endovascular coils.

Methods

One hundred twenty–four Watchman patients with a significant (≥3mm) leak (mean age: 74 ± 9 years; 66.9% males; CHA2DS2–VASc: 4.4 ± 1.7; HAS–BLED: 3.1 ± 1) underwent LAA leak coiling. The expected annual TE risk was estimated based on the patients’ CHA2DS2–VASc and compared with the annualized incidence observed before and after coiling (Fig.1B).

Results

The time between LAAO and leak coiling was 8±6 months [83 patients–year (PY)]; before leak closure, 6 (4.8%) patients had a TE event (annualized rate: 7.2%). Coil deployment was successful in all cases [median n. of coils deployed: 5 (IQR: 2–10)]. Procedure time was 79 ± 40 min; the mean volume of iodinated contrast medium used was 80 ± 43mL. The overall complication rate was 2.4% (1 pericardial tamponade, 2 pericardial effusion). Follow–up TEE after 61±14 days revealed complete LAA sealing or a negligible leak in 117 cases (94.4%); the remaining 7 patients had a moderate leak. During 14±6 months post–coiling (145 PY), 1 (0.8%) patient suffered from stroke. The incidence of TE events was significantly lower after leak closure than before coiling (0.8% vs 4.8%; log–rank p = 0.02; Fig.1A). The annualized TE rates were 7.2% before and 0.7% after leak closure (Fig. 1A). According to the expected rate estimated from the patients’ CHA2DS2–VASc (9.8%), LAAO with and without significant leaks yielded to a risk reduction of 26.5% and 92.9% (Fig. 1B).

Conclusions

Transcatheter leak occlusion via endovascular coils was safe. LAA closure led to a significant reduction in TE events.

P4 LEFT ATRIAL APPENDAGE ANATOMICAL CHANGES FOLLOWING RADIOFREQUENCY–BASED OSTIAL ISOLATION

Background

Left atrial appendage (LAA) electrical isolation (ei) may be achieved via radiofrequency (RF) energy applications at the level of the appendage ostium targeting the sites of earliest activation recorded by a mapping catheter. Notably, RF has long been used in vascular, orthopedic, and aesthetic surgery to promote thermal–induced collagen matrix contraction, fibrosis, and tissue retraction. LAA anatomical changes associated to RF–induced tissue retraction have never been reported.

Objective

To quantify the anatomical changes of the LAA ostium following RF–based LAAei.

Methods

Thirty–four consecutive patients requiring AF ablation with LAAei underwent transesophageal echocardiography (TEE) within 7 days before (baseline TEE) and >6 months after (follow–up TEE) ablation. The diameter of LAA orifice and landing zone were measured at 4 different views (0°, 45°, 90°, 135°). Measurements were performed by two independent reviewers blinded to the patient’s identity.

Results

Among 34 AF patients (68±7yrs, 73.5% males), the LAA morphology was classified as chicken wing in 15 (44%) patients, windsock in 10 (29%), cactus in 6 (18%), and cauliflower in 3 (9%). At baseline TEE, the mean maximum and mean minimum ostial diameters were 25±4mm and 22±4mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 26±4mm and 23±3mm, respectively. On average, LAAei was achieved after 16±7 minutes of RF at a power of 45–47W. Follow–up TEE was performed 257±148 days after LAAei. The median LAA contraction velocity was 0.1 m/s (IQR: 0.04–0.18) and was significantly impaired in all patients. At follow–up TEE, the mean maximum and mean minimum ostial diameters were 19±4mm and 17±3mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 20±4mm and 18±4mm, respectively. The mean relative reduction of the ostium and the landing zone were –24.4% and –22.5%, respectively. Box–Whisker plots of the maximum and minimum ostial diameters before and after LAAei are reported in Fig. 1.

Conclusion

RF led to a > 20% reduction of the diameters of the ostium and the landing zone. These changes may have important implications for a successful percutaneous occlusion procedure and justify a staged approach of isolation and occlusion.

COMPARATIVE STUDY OF CONCURRENT CHEMORADIATION USING PACLITAXEL IN TWO HISTOPATHOLOGICAL SUBTYPES (SQUAMOUS CELL CARCINOMA/ADENOCARCINOMA) OF UNRESECTABLE NON-SMALL CELL LUNG CANCER

Background. Lung cancer is still a global burden and with rising population and increasing life expectancy the incidence of lung cancer is still on the rise. Objective. To compare the treatment response and toxicity of weekly paclitaxel in locally advanced unresectable non-small cell lung cancer (NSCLC), when administered concurrently with external beam radiation to the chest in two different histopathological types – adenocarcinoma and squamous cell carcinoma. Methods. A prospective randomised control trial was conducted in 60 NSCLC patients who were divided into two arms; adenocarcinoma and squamous cell carcinoma arm. All patients were treated with chemoradiation with concurrent paclitaxel 60 mg/m2. Data were evaluated with SPSS version 21.0 for windows with p-value <0.05. Results. Haematological toxicity was the most common side effects evident from the third week of chemotherapy. At the end of 1 month of treatment, two (6.7%) patients had complete response in Arm A and one (3.3%) patient had complete response in Arm B. One (3.3%) patient had disease progression in Arm A and two patients progressed in Arm B. At 7 months post treatment three (10%) patients had complete response in both Arm A and Arm B. Four (13.3%) patients had disease progression in Arm A and ten (33.4%) patients progressed in Arm B. Conclusions. Paclitaxel can be used as an alternative chemotherapeutic agent to the standard cisplatin. However, further studies with larger sample size are required to confirm the findings.

Measurement of Differential Branching Fractions of Inclusive B→X_{u}ℓ^{+}ν_{ℓ} Decays

The first measurements of differential branching fractions of inclusive semileptonic B→X_{u}ℓ^{+}ν_{ℓ} decays are performed using the full Belle data set of 711  fb^{-1} of integrated luminosity at the ϒ(4S) resonance and for ℓ=e, μ. With the availability of these measurements, new avenues for future shape-function model-independent determinations of the Cabibbo-Kobayashi-Maskawa matrix element |V_{ub}| can be pursued to gain new insights in the existing tension with respect to exclusive determinations. The differential branching fractions are reported as a function of the lepton energy, the four-momentum-transfer squared, light-cone momenta, the hadronic mass, and the hadronic mass squared. They are obtained by subtracting the backgrounds from semileptonic B→X_{c}ℓ^{+}ν_{ℓ} decays and other processes, and corrected for resolution and acceptance effects.

Optimal ablation targets during second catheter ablation in patients with persistent AF

Introduction

Pulmonary vein isolation (PVI) is the cornerstone of ablative therapy in atrial fibrillation (AF). However, the one-year success rate after single ablation procedure is known to be up to 60%, necessitating repeat procedures in many.

Purpose

We evaluated the impact of different ablation strategies on procedural success at the second ablation in patients with persistent AF (PerAF).

Methods

Consecutive PerAF patients scheduled to undergo their second ablation were screened and only those that have received PVI plus isolation of left atrial posterior wall (PWI) and superior vena cava (SVC) at the first procedure (n=1390), were included in the analysis. At the second ablation, all reconnected structures were ablated. Additionally, based on operators' decision, non-PV triggers were targeted for ablation.

Patients were classified into two groups based on the ablation strategy: group 1: Re-isolation of reconnected PVs, PW, SVC and group 2: additional ablation of non-PV triggers (from inter-atrial septum, coronary sinus (CS), left atrial appendage (LAA) and crista terminalis). Arrhythmia-monitoring was performed quarterly for 1 year and biannually afterwards. Ablation success was assessed off-antiarrhythmic drugs (AAD).

Results

Of the 1390 patients included in the analysis, 698 were in group 1 and 692 were in group 2.

In group 1, reconnected PV, PW and SVC were re-isolated in 98 (14%), 311 (44.5%) and 173 (24.8%) respectively. In 131 (18.7%) patients, in the absence of any reconnection, CS was empirically isolated.

In group 2, PV, PW and SVC were re-isolated in 83 (12%), 270 (39%) and 113 (16.3%) patients respectively. Additionally, non-PV triggers were ablated in 505 (73%) and empirical isolation of LAA and CS in the absence of detectable triggers and PV reconnection was performed in 187 (27%).

At 2 years of follow-up, 425 (61%) and 602 (87%) from group 1 and 2 were arrhythmia-free off-AAD (p&lt;0.001).

Conclusion

Including non-PV triggers as targets for ablation at the repeat procedure was associated with significantly higher success rate in persistent AF.

Funding Acknowledgement

Type of funding sources: None.

Long-term outcome of endocardial-only versus combined endocardial-epicardial homogenization of the scar for treatment of ventricular tachycardia in patients with ischemic cardiomyopathy

Introduction

We investigated the ablation success of scar homogenization with combined (epicardial + endocardial) versus endocardial-only approach for ventricular tachycardia (VT) in patients with ischemic cardiomyopathy (ICM) at 5 years of follow-up.

Method

Consecutive ICM patients undergoing VT ablation at our center were classified into group 1: endocardial scar homogenization and group 2: endocardial +epicardial scar homogenization. Patients with previous open heart surgery were excluded.

All patients underwent bipolar substrate mapping with standard scar settings defined as normal tissue &gt;1.5 mV and severe scar &lt;0.5 mV. Non-inducibility of monomorphic VT was the procedural endpoint in both groups. Patients were followed up twice a year for 5 years with implantable device interrogations.

Results

A total of 361 (Group 1: 291 and group 2: 70) patients were included in the study (mean age: 67 years, male: 88.4%).

At 5 years, significantly higher number of patients from group 2 remained arrhythmia-free (figure 1). Of those patients, 87 (45%) and 51 (89%) from group 1 and 2 respectively were off-anti-arrhythmic drugs (AAD) (p&lt;0.001). After adjusting for age, gender, hypertension, diabetes, and obstructive sleep apnea, scar homogenization using endo-epicardial approach was associated with 51% less recurrence compared to the endocardial ablation strategy (Hazard Ratio: 0.49, 95% CI: 0.27–0.89, p: 0.02).

Conclusion

In this series of patients with ischemic cardiomyopathy and VT, endo-epicardial scar homogenization was associated with a lower need for AAD and a significantly lower recurrence rate at 5-years of follow-up compared to the endocardial ablation alone.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Linear increase in the number of non-pulmonary vein triggers from paroxysmal to persistent and long-standing persistent AF in patients undergoing repeat procedure after successful isolation of pulmona

Introduction

This study evaluated the prevalent triggers responsible for recurrence following successful PVI in different types of atrial fibrillation (AF).

Methods

Consecutive AF patients undergoing repeat catheter ablation with permanently isolated PV were included in the analysis. High-dose isoproterenol challenge (20- 30μg/min for 15–20min) was used to confirm PV reconnection and identify non-PV triggers.

Circular mapping catheter (CMC) was used to map the site of origin of significant ectopic activity by comparing the activation sequence of the sinus beat with that of the ectopic beat. For the coronary sinus (CS), ablation catheter was positioned at the level of the mitral valve annulus, parallel to the one positioned in the CS. Left atrial appendage (LAA) firing was detected by placing the CMC in the left superior PV and thus recording far-field potentials from the LAA.

Results

This prospective study included 1850 AF patients undergoing repeat AF ablation (Table 1), of which 573 (31%) had received one and the remaining 1277 patients had received 2 earlier ablations. Permanent PVI was confirmed with isoproterenol challenge.

Table 1 shows the distribution of non-PV triggers. A linear increase in the number of non-PV triggers was observed from PAF to PerAF to LSPAF. Significantly higher number of LSPAF patients had detectable non-PV triggers compared to PerAF and PAF cases.

Conclusion

We observed a linear increase in the number of non-PV triggers in PAF to PerAF and LSPAF patients experiencing recurrence with successful isolation of PVs. As non-PV triggers are often not targeted by operators, this could be the underlying mechanism for more frequent recurrences in non-paroxysmal AF.

Funding Acknowledgement

Type of funding sources: None. Table 1

Benefits of early intervention with catheter ablation in patients with atrial fibrillation

Background

Radiofrequency catheter ablation, a widely recognized therapeutic option for atrial fibrillation (AF) has limited success rate as it is influenced by several factors including duration of AF.

Purpose

We evaluated the ablation success in AF patients intervened early versus late in the disease course.

Methods

Consecutive AF patients undergoing their first catheter ablation in 2015–16 at our center were included in the analysis. Patients were classified into two groups based on the time to ablation after AF diagnosis; 1) early: ≤12 months and 2) late: &gt;12 months.

All received PV isolation plus isolation of posterior wall and superior vena cava. Additionally, in non-paroxysmal AF cases, non-PV triggers were identified with isoproterenol-challenge and ablated. Patients were prospectively followed up for 3 years with regular rhythm monitoring.

Results

A total of 752 and 1248 patients were included in the “early” and “late” group respectively. Baseline characteristics of the study population is provided in Table 1 A. At 4 years of follow-up, overall success rate off-antiarrhythmic drugs was significantly higher in the “early” group (65.4% vs 57%, p&lt;0.001). After stratification by AF type, “early” group was still associated with significantly higher success rate compared to the “late” group (Table 1B).

Conclusion

In this large series with standardized ablation strategy, early intervention with catheter ablation was associated with higher success rate in all AF types.

Funding Acknowledgement

Type of funding sources: None. Table 1

Recovery of conduction following high power short duration approach in radiofrequency catheter ablation for atrial fibrillation: a single-center experience

Introduction

High-power short-duration (HPSD) ablation is currently being adopted by many as the preferred procedural technique in atrial fibrillation (AF). However, the optimal duration of energy delivery to successfully create a durable lesion is not clear yet.

Purpose

We evaluated the association of electrical reconnection with lesion-duration in HPSD ablation.

Methods

Consecutive AF patients undergoing repeat procedure after a prior HPSD ablation with or without isolation of left atrial appendage (LAA) and coronary sinus (CS) were included in this analysis. HPSD ablation was defined as ablation with maximum temperature setting at 420C and power delivery at 45 W for 10–15 sec (5 seconds in the CS area and posterior wall near the esophagus). In some patients a mechanical esophageal deviation tool was used to deflect the esophagus away from the ablation site.

Results

A total of 2249 AF patients (with LAA and CS isolation: 1451; without LAA and CS isolation: 798) receiving redo ablation after a prior HPSD procedure were included in the analysis. At the prior procedure with the HPSD approach, mean duration of ablation was significantly shorter in the area facing the esophagus compared to elsewhere (5.2±1.5 vs 12.5±1.7 seconds, p&lt;0.001). Application duration was reduced to &lt;10 sec to avoid overheating and steam pops in 1221 (84%) patients receiving LAA and CS isolation.

At the redo, recovery of conduction was noted in the CS (592, 40.8%), LAA (493, 34%), and PV and left atrial posterior wall (LAPW) (310, 13.8%). Of the 310 patients with LAPW reconnection, 91% (n=282) had the conduction recovered in the area facing the esophagus.

In 73 patients, esophageal displacement device was used during the prior HPSD ablation. Average duration of ablation lesions in LAPW among those 73 patients was 9.2±2 seconds. PV-LAPW reconnection was observed in 3/73 (4.1%) patients.

Conclusion

HPSD ablation with lesion duration of &lt;10 sec was associated with conduction recovery in the LAA, CS and the LAPW area facing esophagus.

Funding Acknowledgement

Type of funding sources: None.

P–796 Trial of Autologous Marrow derived Stem Cell Ovarian Transplantation (TAMSCOT) in young infertile women with diminished ovarian reserve for ovarian rejuvenation – HOPE still persists

Study question

Does autologous bone marrow derived stem cell (BMDSC) ovarian transplantation optimize ovarian reserve parameters in young infertile women with diminished ovarian reserve (DOR) ?

Summary answer

The autologous stem cell ovarian transplantation (ASCOT) improves AFC and AMH by facilitating the recruitment of existing dormant follicles in young women with DOR.

What is known already

Oocyte donation is the practical therapeutic option when patients with premature ovarian ageing desire pregnancy. It involves significant psychological burden in terms of not able to have their own biological child. ASCOT has opened new doors in poor responders and premature ovarian insufficiency through its beneficial effects on ovarian reserve and IVF outcomes. However recent studies have shown contradictory results in terms of its efficacy. No prior study has been contemplated in DOR group

Study design, size, duration

An open label non randomized controlled trial was conducted at Division of Reproductive Medicine in collaboration with stem cell facility at tertiary care institute. Forty two infertile women less than 35 years age with DOR (AFC&lt;5, AMH&lt;1.2ng/ml and /or high FSH&gt;8IU/l) were enrolled in the study during a period from January 2020 to December 2020. 20 women who did not opt for the intervention were treated as control group whereas 22 women received the intervention.

Participants/materials, setting, methods

Baseline hormonal profile ( Day 2 FSH, estradiol, AMH and AFC) was done in all patients. Women with abnormal uterine cavity, endometriosis, prior ovarian surgery, abnormal karyotype were excluded. Bone marrow aspiration followed by mesenchymal stem cells isolation was performed. The stem cells were transplanted in both the ovaries through transvaginal route on the same day. Follow up visits were planned at one and six months to assess ovarian reserve parameters.

Main results and the role of chance

The mean age, BMI and duration of infertility were comparable between the control and study group (29.5±3.34vs29.36±2.95years, 21.51±1.40vs21.87±1.93kg/m2, 6.9±1.94vs7. 04±3.67 years) . The positive response in terms of improved AMH and AFC was seen in 68% (15/22) patients. The mean number of stem cells injected in these women were 77.71±25.33 million. At first follow up, there was no significant difference between mean FSH, estradiol levels and mean right and left ovarian volume (9.23±3.95 vs 9.02±3.92mIU/l, 61.46±29.25 vs 68.12±62.52 pg/ml, 2.82±2.18 vs 2.44±1.25 cc, 2.02±1.54 vs 2.72±1.06 cc, p &lt; 0.05). There was significant increase in AMH and AFC values as compared to baseline (0.79±0.43 vs 1.26±0.82ng/ml, p = 0.03; 3.47±1.30 vs 6.40±2.23, p &lt; 0.001). At second follow up visit, the significant increase in ovarian reserve persisted for AMH and AFC (0.79±0.43 vs 1.22±0.76 ng/ml, p = 0.02; 3.47±1.30 vs 6.93±1.71,p&lt;0.001). There was no significant difference between serum FSH , Estradiol and ovarian volume. None of the patients developed any complication and the improvement in AFC and AMH persisted during 10 month follow up period.

Limitations, reasons for caution

The limitation of present study is small sample size and non randomization. However, time period for which positive effect lasts has not been documented in earlier studies. This study is currently being endeavored, and women with improved ovarian reserve are followed up for any spontaneous conception or following assisted reproduction.

Wider implications of the findings: The present study demonstrates beneficial role of stem cells in improving ovarian reserve parameters in women with DOR with no acquired cause. If supported by future randomized clinical studies, it could represent a paradigm shift for fertility treatment in these women providing an opportunity to have their own biological child.

Trial registration number

CTRI/2020/01/022726

P-796 Trial of Autologous Marrow derived Stem Cell Ovarian Transplantation (TAMSCOT) in young infertile women with diminished ovarian reserve for ovarian rejuvenation – HOPE still persists

Study question

Does autologous bone marrow derived stem cell (BMDSC) ovarian transplantation optimize ovarian reserve parameters in young infertile women with diminished ovarian reserve (DOR) ?

Summary answer

The autologous stem cell ovarian transplantation (ASCOT) improves AFC and AMH by facilitating the recruitment of existing dormant follicles in young women with DOR.

What is known already

Oocyte donation is the practical therapeutic option when patients with premature ovarian ageing desire pregnancy. It involves significant psychological burden in terms of not able to have their own biological child. ASCOT has opened new doors in poor responders and premature ovarian insufficiency through its beneficial effects on ovarian reserve and IVF outcomes. However recent studies have shown contradictory results in terms of its efficacy. No prior study has been contemplated in DOR group

Study design, size, duration

An open label non randomized controlled trial was conducted at Division of Reproductive Medicine in collaboration with stem cell facility at tertiary care institute. Forty two infertile women less than 35 years age with DOR (AFC&lt;5, AMH&lt;1.2ng/ml and /or high FSH&gt;8IU/l) were enrolled in the study during a period from January 2020 to December 2020. 20 women who did not opt for the intervention were treated as control group whereas 22 women received the intervention.

Participants/materials, setting, methods

Baseline hormonal profile ( Day 2 FSH, estradiol, AMH and AFC) was done in all patients. Women with abnormal uterine cavity, endometriosis, prior ovarian surgery, abnormal karyotype were excluded. Bone marrow aspiration followed by mesenchymal stem cells isolation was performed. The stem cells were transplanted in both the ovaries through transvaginal route on the same day. Follow up visits were planned at one and six months to assess ovarian reserve parameters.

Main results and the role of chance

The mean age, BMI and duration of infertility were comparable between the control and study group (29.5±3.34vs 29.36±2.95years, 21.51±1.40vs21.87±1.93kg/m2, 6.9±1.94vs7.04±3.67 years). The positive response in terms of improved AMH and AFC was seen in 68% (15/22) patients. The mean number of stem cells injected in these women were 77.71±25.33 million. At first follow up, there was no significant difference between mean FSH, estradiol levels and mean right and left ovarian volume (9.23±3.95 vs 9.02±3.92mIU/l, 61.46±29.25 vs 68.12±62.52 pg/ml, 2.82±2.18 vs 2.44±1.25 cc, 2.02±1.54 vs 2.72±1.06 cc, p &lt; 0.05). There was significant increase in AMH and AFC values as compared to baseline (0.79±0.43 vs 1.26±0.82ng/ml, p = 0.03; 3.47±1.30 vs 6.40±2.23, p &lt; 0.001). At second follow up visit, the significant increase in ovarian reserve persisted for AMH and AFC (0.79±0.43 vs 1.22±0.76 ng/ml, p = 0.02; 3.47±1.30 vs 6.93±1.71,p&lt;0.001). There was no significant difference between serum FSH, Estradiol and ovarian volume. None of the patients developed any complication and the improvement in AFC and AMH persisted during 10 month follow up period.

Limitations, reasons for caution

The limitation of present study is small sample size and non randomization. However, time period for which positive effect lasts has not been documented in earlier studies. This study is currently being endeavored, and women with improved ovarian reserve are followed up for any spontaneous conception or following assisted reproduction.

Wider implications of the findings

The present study demonstrates beneficial role of stem cells in improving ovarian reserve parameters in women with DOR with no acquired cause. If supported by future randomized clinical studies, it could represent a paradigm shift for fertility treatment in these women providing an opportunity to have their own biological child

Trial registration number

CTRI/2020/01/022726

Role of MR cisternography in the diagnosis of cerebrospinal fluid rhinorrhoea with diagnostic nasal endoscopy and surgical correlation

Objectives : To study the usefulness and accuracy of MR cisternography as noninvasive study in the diagnosis of cerebrospinal fluid (CSF) fistula with diagnostic sinonasal endoscopy and surgical correlation. Material and Methods: Twenty four patients with clinically suspected CSF rhinorrhoea were examined for CSF fistula with MR cisternography. The MR imaging technique included 3mm thin T2 weighted coronal and sagittal sections using Fast spin echo. In addition 1.5mm thin T2 weighted coronal sections were also obtained using CISS (Constructive Interference in Steady State) sequence. MR findings were correlated with diagnostic sinonasal endoscopy and surgical findings. Results : MR cisternography demonstrated the presence of fistula in 17 patients, absence of fistula in seven patients. Out of 17 patients with fistula, the diagnosis could be confirmed in 14 patients by diagnostic sinonasal endoscopy/surgery. Out of the seven patients without fistula, there was positive correlation in six patients when they were followed up clinically and by diagnostic nasal endoscopy. However in one patient, fistula was demonstrated on CT cisternography and was confirmed on sinonasal endoscopic surgery. The accuracy, sensitivity of MR cisternography was 96, 94% respectively. Conclusion : MR cisternography is a useful and accurate noninvasive study in localizing the site and extent of CSF fistula.

Tuning up the photovoltaic performances upon the utility of diketopyrrolopyrrole in PEO-based gel polymer electrolytes

The role of diketopyrrolopyrrole (DPP-H) as an additive on the ionic conductivity of poly(ethylene oxide) (PEO)-based gel polymer electrolytes (GPE) was studied for DSSC applications. The pure PEO/PC/KI/TPAI/I2 GPE was prepared with a mixture of propylene carbonate (PC) as a non-volatile plasticizer and iodide salts, such as potassium iodide (KI), tetrapropylammonium iodide (TPAI) and iodine (I2), together with PEO. The modified GPEs were prepared with different weight percentage (wt%) ratios (0.5%, 0.75%, 1% and 1.25%) of DPP-H using acetonitrile as a solvent. The polymer gel electrolytes were characterized by X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR), and the electrochemical properties were analyzed to relate the nature of the polymer and iodine ion conducting properties. The pure PEO/PC/TPAI/KI/I2 electrolyte exhibited an ionic conductivity value of 0.084 mS·cm-1 at room temperature. Upon the optimized addition of DPP-H (0.75 wt%), the ionic conductivity was found to be improved to a maximum value of 0.393 mS·cm-1, and the highest diffusion coefficient of 1.02 × 10-6 cm2 s-1 was observed. The optimized GPEs photovoltaic characterization studies showed higher power conversion efficiency (PCE) of 6.69% for DSSC under light illumination intensity of 100 mW cm-2. The same was compared with pure electrolyte, which delivered PCE of 4.39%. To gain an in-depth understanding of the interfacial resistance of the fabricated devices, the electron lifetime and transient photo response was analyzed. These above studies showed that prepared GPE could be an efficient alternative for traditional DSSCs with liquid electrolyte.

Linear lesions in dermatology: a clinicoaetiopathological study

BACKGROUND

Linear lesions are fairly common in our daily practice. However, the appearance of these lesions can vary, thus complicating the diagnosis.

AIMS

To study the various clinical presentations, the demographic profile of patients and the clinicopathological correlations of dermatoses presenting with a linear distribution.

METHODS

We conducted an institution-based, cross-sectional, descriptive study of 281 consecutive patients with linear lesions attending dermatology clinics. MedCalc software (V11.6) was used for statistical analysis.

RESULTS

Patients were divided into eight groups: lesions along the lines of Blaschko (n = 136), lesions along blood vessels (n = 3), lesions along lymphatics (n = 3), Koebner phenomenon (n = 24), autoinoculation (n = 24), external factors (n = 45), infestations (n = 2) and 'other' (n = 44). The mean age at presentation was 24.50 ± 18.82 years and the male/female ratio was 1.32 : 1. The commonest symptom was itching/burning (56.94% of patients), while the commonest site was the arm (44.48%); followed by the leg (30.60%), trunk and abdomen (22.42%), head and neck (19.20%), and genitalia (0.35%). Apart from the common cases, there was a wide gamut of rare conditions (e.g. angiokeratoma circumscriptum naeviforme, porokeratotic eccrine ostial and dermal duct naevus, Blaschko-linear syringocystadenoma papilliferum, progressive cribriform and zosteriform hyperpigmentation, unilateral naevoid acanthosis nigricans, fixed drug eruption, discoid lupus erythematosus).

CONCLUSION

Linear lesions act as diagnostic clues to many dermatological conditions, therefore, the importance of meticulous examination in clinical dermatology cannot be overemphasized.

Evidence for X(3872)→J/ψπ^{+}π^{-} Produced in Single-Tag Two-Photon Interactions

We report the first evidence for X(3872) production in two-photon interactions by tagging either the electron or the positron in the final state, exploring the highly virtual photon region. The search is performed in e^{+}e^{-}→e^{+}e^{-}J/ψπ^{+}π^{-}, using 825  fb^{-1} of data collected by the Belle detector operated at the KEKB e^{+}e^{-} collider. We observe three X(3872) candidates, where the expected background is 0.11±0.10 events, with a significance of 3.2σ. We obtain an estimated value for Γ[over ˜]_{γγ}B(X(3872)→J/ψπ^{+}π^{-}) assuming the Q^{2} dependence predicted by a cc[over ¯] meson model, where -Q^{2} is the invariant mass squared of the virtual photon. No X(3915)→J/ψπ^{+}π^{-} candidates are found.

Surgical management of the odontogenic keratocyst: A 20-year experience

The objective of this study was to describe the authors' long-term experience with the management of odontogenic keratocysts (OKCs). All OKC cases treated at the study centre between 1999 and 2015, with a minimum of 5 years of follow-up by December 2019, were reviewed retrospectively. Operative procedures including decompression/marsupialization, enucleation (E), E+Carnoy's solution (CS), E+CS+peripheral ostectomy (PO), and resection were assessed for complete resolution, partial resolution, and recurrence rates. In the parakeratinized non-syndromic group, E+CS+PO resulted in the lowest recurrence rate among the minimally invasive procedures (4.3%), while enucleation resulted in the highest rate (60%). Regarding the other modalities, recurrence was 12.5% for decompression, 11.5% for marsupialization, 16.7% for E+CS, 26.7% for E+PO, and 0% for resection. In the syndromic group, marsupialization resulted in a significantly higher recurrence (23.1%), while E+CS+PO cases showed no recurrence. No recurrence was observed in the orthokeratinized group patients treated with marsupialization or with E+CS. Based on clinico-radiographic features and observed results, it is concluded that OKC, although having a high recurrence rate, is a benign lesion and responds well to conservative procedures in most cases. Radical procedures should be reserved for unresponsive lesions and those with extensive tissue destruction.

The transition to Xpert MTB/RIF ultra: diagnostic accuracy for pulmonary tuberculosis in Kampala, Uganda

BACKGROUND

The World Health Organization (WHO) has endorsed the next-generation Xpert MTB/RIF Ultra (Ultra) cartridge, and Uganda is currently transitioning from the older generation Xpert MTB/RIF (Xpert) cartridge to Ultra as the initial diagnostic test for pulmonary tuberculosis (TB). We assessed the diagnostic accuracy of Ultra for pulmonary TB among adults in Kampala, Uganda.

METHODS

We sampled adults referred for Xpert testing at two hospitals and a health center over a 12-month period. We enrolled adults with positive Xpert and a random 1:1 sample with negative Xpert results. Expectorated sputum was collected for Ultra, and for solid and liquid culture testing for Xpert-negative patients. We measured sensitivity and specificity of Ultra overall and by HIV status, prior history of TB, and hospitalization, in reference to Xpert and culture results. We also assessed how classification of results in the new "trace" category affects Ultra accuracy.

RESULTS

Among 698 participants included, 211 (30%) were HIV-positive and 336 (48%) had TB. The sensitivity of Ultra was 90.5% (95% CI 86.8-93.4) and specificity was 98.1% (95% CI 96.1-99.2). There were no significant differences in sensitivity and specificity by HIV status, prior history of TB or hospitalization. Xpert and Ultra results were concordant in 670 (96%) participants, with Ultra having a small reduction in specificity (difference 1.9, 95% CI 0.2 to 3.6, p=0.01). When "trace" results were considered positive for all patients, sensitivity increased by 2.1% (95% CI 0.3 to 3.9, p=0.01) without a significant reduction in specificity (- 0.8, 95% CI - 0.3 to 2.0, p=0.08).

CONCLUSIONS

After 1 year of implementation, Ultra had similar performance to Xpert. Considering "trace" results to be positive in all patients increased case detection without significant loss of specificity. Longitudinal studies are needed to compare the benefit of greater diagnoses to the cost of overtreatment.

Risk factors for progression of paroxysmal to persistent atrial fibrillation following successful PV isolation

Background

Progression from paroxysmal (PAF) to persistent atrial fibrillation (PerAF) following effective PV isolation (PVI) has important clinical implications, as it is relevant for subsequent management of the arrhythmia.

Objective

We evaluated risk factors responsible for progression of PAF to PerAF following successful PVI.

Methods

Consecutive AF patients that received their first catheter ablation as well as the first redo at our center were identified (n=1352). Patients were included in group 1 if the diagnosis was PAF at both first and redo procedure (PAF to PAF) and group 2 if PAF at index progressed to PerAF at redo. All patients received PVI plus isolation of LA posterior wall and SVC at the first procedure.

Results

A total of 822 patients remained as PAF at redo, whereas 530 (39%) progressed from PAF to PerAF. Clinical characteristics of the study population are presented in table 1. In multivariate analysis, BMI (OR 1.02, 1.01–1.04, p=0.04), hypertension (1.4, 1.08–1.8, p=0.01), heart failure (1.67, 1.03–2.69, p=0.03), LA size (2.75, 2.29–3.31, p&lt;0.001) were independent predictors of progression of PAF to PerAF. Data on serum-transthyretin level was available for 37 and 48 patients in group 1 and 2 respectively. It was &lt;18 mg/dL (normal) in 33 (68.7%) patients in group 2 vs 6 (16.2%) in group 1 (p&lt;0.001).

Conclusion

In our patients, after successful PVI, progression of PAF to PerAF was mediated by independent risk factors such as high BMI, heart failure, hypertension, larger LA size and lower LVEF.

Funding Acknowledgement

Type of funding source: None

Extended Pulmonary Vein Isolation: is it sufficient to achieve long-term sinus rhythm in octogenarian women with atrial fibrillation?

Background

Atrial fibrillation (AF) is a disease of the elderly and women typically present with AF at an older age than men do. Moreover, they tend to experience more symptoms and post-ablation recurrences, have worse quality of life and increased risk of stroke and mortality.

Objective

We evaluated long-term efficacy of our standard ablation approach of extended pulmonary vein isolation (PVI) in octogenarian women undergoing their first AF ablation.

Methods

Consecutive female AF patients aged ≥80 years receiving their first catheter ablation at our center were included in the analysis. Our standard ablation approach at the first procedure includes PVI + empirical isolation of left atrial posterior wall (LAPW) and superior vena cava (SVC). Complete abolition of all potentials rather than decrease in amplitudes was the procedural end point. Patients were prospectively monitored at regular intervals for 3 years after the index procedure with event recorders, 12-lead ECG, cardiology evaluation at office visits and 7-day Holter monitoring.

Results

A total of 194 patients with mean age of 84.2±1.4 years were included in the analysis. Of the 194, 120 (61.8%) had non-paroxysmal AF. All received PVI+ isolation of LAPW and SVC. Acute procedural success was achieved in 100% of cases.

At 3 years of follow-up, 24 (12.4%) patients remained in sinus rhythm; 22 on- and 2 off-antiarrhythmic drugs (AAD). All of the 23 patients had paroxysmal AF as their initial diagnosis.

Of the 170 patients experiencing recurrence, 147 underwent repeat ablation. PV/PW/SVC reconnection was noted in only 6 (4.1%) patients at redo. Triggers originating from non-PV sites were targeted for ablation in all. At 1.5 years after the repeat procedure, 136 (92.5%) patients were in sinus rhythm; 131 off-AAD and 5 patients on-AAD.

Conclusion

Extended PVI including isolation of posterior wall and SVC was not sufficient to maintain long-term sinus rhythm in majority of octogenarian women, regardless of AF type. Moreover, non-PV triggers rather than PV reconnection was the major cause of recurrence in this subset of AF population.

Funding Acknowledgement

Type of funding source: None

Risk factors and effective ablation strategy in patients presenting with left atrial flutter with no previous ablation for atrial fibrillation

Background

A typical left atrial flutter (LAFL) may occur as a proarrhythmic complication of ablation for atrial fibrillation (AF).

Objective

We evaluated the risk factors and the best ablation strategy for LAFL in patients with no prior AF ablation.

Methods

Consecutive patients undergoing first catheter ablation for AFL with no prior procedure for AF were included in this prospective analysis. Based on the ablation strategy, patients were divided into, Group 1: PVI+ Flutter ablation (ablation of re-entry circuits) and Group 2: PVI+ Non-PV trigger ablation (targeting areas of focal activity as triggers). 3-D mapping of the LA was performed during tachycardia to identify the reentrant circuit.

PV isolation was performed in all patients. In group 1, ablation line was chosen to transect the area critical for the circuit (roof and mitral line). In group 2, ectopic beats arising from extra-PV foci detected by isoproterenol challenge were ablated. Off-drug success rate was assessed in all.

Results

A total of 92 and 90 patients were included in group 1 and 2 respectively. Baseline characteristics are provided in table 1. Pre-existent LA scar was detected in 91.3% and 90% of patients in group 1 and 2 respectively.

At 2 years of follow-up, 11/92 (12%) from group 1 and 60/90 (66.7%) from group 2 remained arrhythmia-free off-drugs (p&lt;0.001). In the multivariate analysis, PVI +flutter ablation was detected to be associated with significantly high risk of recurrence [HR: 3.92 (95% CI: 2.52–6.1, p&lt;0.001)]

Conclusion

In this series of patients presenting with LAFL with no earlier AF ablations, pre-existent left atrial scar was detected in majority of cases and PVI+ non-PV trigger ablation provided significantly better success rate than PVI+ flutter ablation.

Funding Acknowledgement

Type of funding source: None

History of household member with tuberculosis or related death in newly diagnosed patients in India

Among new smear-positive pulmonary tuberculosis (TB) patients aged ⩾15 years from marginalised populations in India, one in four had a history of a household member with TB and one in 10 had a TB-related death in the household. This contribution of household transmission to overall TB transmission provides evidence for a potential population-level benefit of TB preventive treatment for all household contacts (without active TB). Females with TB had a significantly higher household TB exposure than males. Targeted TB preventive treatment (if implemented in a phased manner) among female household contacts may be explored after considering other factors.

Effect of Temperature on Oxymyoglobin and Metmyoglobin Denaturation Properties

ObjectivesPremature browning is a condition where the interior of patty/steak will appears fully cooked before the temperature necessary to kill foodborne pathogens is reached. Previous research reported that approximately 50% of ground beef retailed in the US is susceptible to premature browning. Myoglobin form present in the interior of steak or patties determines the cooked color appearance. Although previous studies noted that myoglobin denaturation is primarily responsible for the cooked color appearance, limited knowledge is currently available about the effect of temperature on oxymyoglobin and metmyoglobin denaturation properties. The objective of the current study was to determine the effects of myoglobin forms on thermal stability using circular dichroism spectroscopy.Materials and MethodsOxymyoglobin and metmyoglobin solutions at pH 5.6 in 50 mM sodium phosphate buffer were incubated in a continuous heat increment water bath for 10 min. At specific temperature points (65, 71, 73, and 76°C), myoglobin denaturation was determined by changes in myoglobin concentration and by protein unfolding (fluorescence and absorbance) methods. The myoglobin thermal stability was also determined by circular dichroism spectroscopy. Changes in secondary protein structure were determined every 2°C from 52 to 92°C. The data were analyzed as completely randomized using the Mixed Procedure of SAS. A significance level of 0.05 was used to determine differences between means.ResultsOxymyoglobin had greater (p < 0.05) unfolding (as indicated by absorbance changes) than metmyoglobin at all temperatures. However, at 65, 71, and 73°C there were no differences (p > 0.05) in fluorescence intensities between myoglobin forms. Circular dichroism spectroscopy indicates that oxymyoglobin is more heat labile than metmyoglobin.ConclusionThe results indicate that oxymyoglobin had greater denaturation and unfolding than metmyoglobin. Use of appropriate myoglobin denaturation quantification technique will help characterize premature browning.

Myoglobin Modeling to Study Species-Specific Differences in the Distance Between Heme Iron and Proximal and Distal Histidines

ObjectivesSpecies-specific differences in amino acid sequence influence myoglobin redox properties. Previous studies reported that the number and location of histidine residues can influence myoglobin redox stability. However, limited knowledge is currently available on the species-specific differences in the distances between the proximal (His 93) and distal (His 64) histidines and the heme iron in myoglobin. The objective of the current research was to utilize homology-based modeling to determine the distances between the proximal and distal histidines and the heme iron in the myoglobins from beef, pork, goat, bison, sheep, water-buffalo, venison, and emu.Materials and MethodsThe homology-based modeling was conducted using the Iterative Threading Assembly Refinement server (I-TASSER), which identifies the homologous structure models of myoglobins (beef, pork, goat, bison, sheep, water-buffalo, venison, and emu) from Protein Data Bank (PDB) using an algorithm named Local Meta-Threading-Server. The secondary structure of the target protein was predicted based on sequence information from the Protein Secondary Structure PREDiction algorithm. The lowest free energy conformations of the proteins were determined by SPICKER (a clustering approach to identify near-native protein folds). Refinement of the low free energy conformations were done by using Fragment Guided Molecular Dynamics simulations and ModRefiner. Prediction of the ligand-binding site of the target proteins were made by COACH algorithm. The distances between histidines (His 64 and His 93) and the iron in the heme group in the predicted structure of eight different species were determined using PyMOL, a computer software used for molecular visualization.ResultsThe homology-based modeling has shown that despite having 80% sequence similarity and conserved histidine residues (His 64 and His 93), the distance between the distal histidine (His 64) and heme iron varied between 4.3–5.5 Angstrom. Pork myoglobin has the shortest distance, and beef myoglobin has the longest distance. The distance between the proximal histidine (His 93) to the heme varied between 1.9 to 3 Angstrom; sheep myoglobin had the shortest and bison had the longest.ConclusionThe results suggest that in addition to the inherent differences in muscle biochemistry, variations in myoglobin structure also contributes to species-specific differences in meat color.

Simulation-Based Approach for Probing Rheology-Processing-Structure Relationships in Foam Blow Molding

The broad objective of this work was to demonstrate a modelling and simulation framework for foam blow molding using commercially available simulation software. The simulation framework would have to account for the initial morphology of the foam, the relationship between the morphology and the rheological and deformation characteristics of the foam at high temperatures and high strains that are typically encountered during blow molding, and correlate the strains developed during blow molding to the morphological aspects in the resulting blow molded part. These aspects are addressed in this paper using simulations of uniaxial tensile deformation of a virtual representative volume element of a foam microstructure (rendered in DIGIMAT-FE) to derive the nonlinear tensile response of the foam at high temperatures (using ABAQUS). The resulting simulated stress-strain curve is employed to parameterize a nonlinear rheological constitutive equation. These parameters are then employed for the homogenized representation of the foam in the blow molding simulation carried out in B-SIM, a commercially available simulation software for blow molding. The regions where the simulated parison has undergone primarily uniaxial elongation are then mapped back to the expected local foam morphology using the transfer functions derived from the RVE simulations. These steps result in a preliminary and simple demonstration of the simulation framework, and offer a template that can be detailed further with experimental rheological information on actual foamed parisons, and more detailed post-processing algorithms to correlate multiaxial elongations with microstructure.

P4761Impact of focal ablation versus isolation of the coronary sinus in patients undergoing repeat radiofrequency catheter ablation of persistent atrial fibrillation

Introduction

Non-pulmonary vein (PV) triggers originating from the coronary sinus (CS) are a common finding in atrial fibrillation (AF) patients. To date, no studies have investigated the clinical impact of focal ablation versus isolation of the CS in patients presenting triggers from this area.

Purpose

This study analyzed the effectiveness of two different approaches for CS ablation (total isolation vs focal ablation) in persistent AF patients undergoing repeat AF ablation.

Methods

Consecutive persistent AF patients undergoing repeat ablation were enrolled in this prospective analysis. All patients had triggers from the CS documented during high-dose isoproterenol. Pulmonary vein antrum isolation (PVAI) extended to the posterior wall (PW) plus superior vena cava (SVC) isolation was performed in all patients at first procedure. At repeat procedure, PV, PW, and SVC were re-isolated, if needed. Focal ablation or isolation of the CS was performed based on operator's choice either at first and/or repeat procedure, along with ablation of other non-PV triggers. Patients with triggers from left atrial appendage were excluded from the study.

Results

Overall, 628 consecutive patients (73.4% male, age 66.9±9.0 years) were enrolled. On the basis of the CS ablation strategy, patients were categorized into two groups: Group I received CS isolation (n=389) and Group II received CS focal ablation (n=239). Major clinical characteristics were not different between groups. PV reconnection was documented in 55 (14.1%) patients of Group I and 33 (13.8%) of Group II. The incidence of procedure-related complications was similar between the two groups (10 [2.6%] in Group I vs 6 [2.5%] in Group II; p=0.9). After a follow-up of 18±8 months, 276 (71%) patients in Group I and 115 (48%) in Group II remained arrhythmia-free (p<0.001, figure.1). After adjusting for age, gender and clinically relevant variables, CS isolation was associated with a significantly higher arrhythmia-free survival rate (HR: 0.47; 95% CI: 0.37–0.61, p-value<0.001).

Conclusions

In patients with documented triggers from the CS undergoing repeat ablation of persistent AF, isolation rather than focal ablation of the CS significantly increased freedom from atrial tachyarrhythmias in the long term.

Accuracy and incremental yield of urine Xpert MTB/RIF Ultra versus Determine TB-LAM for diagnosis of pulmonary tuberculosis

The performance of urine Xpert MTB/RIF Ultra (Xpert Ultra) for pulmonary TB diagnosis is unknown. HIV-positive and HIV-negative adults were enrolled at two health facilities in Kampala, Uganda. We compared the accuracy of urine Xpert Ultra and Determine TB-LAM in reference to sputum-based testing (positive Xpert MTB/RIF or culture), and assessed incremental yield. Urine Xpert Ultra had low sensitivity (17.2%, 95% CI 12.3-23.2) but high specificity (98.1%, 95% CI 94.4-99.6). Sensitivity reached 50.0% (95% CI 28.2-71.8) among HIV-positive patients with CD4 <100 cells/μL. Compared to Determine TB-LAM, urine Xpert Ultra was 9.4% (95% CI 3.8-14.9, P = 0.01) more sensitive, and 17.2% (95% CI 4.5-29.8, P = 0.01) more sensitive among HIV-positive patients. However, the incremental sensitivity of urine Xpert Ultra relative to sputum Xpert MTB/RIF was only 1% (95% CI -0.9 to 2.8). Urine Xpert Ultra could be an alternative for patients with advanced HIV infection unable to produce sputum.

Water vapor flux in tropical lowland rice

A field experiment was conducted at Indian Council of Agricultural Research-National Rice Research Institute, Cuttack, Odisha, India in the dry seasons of 2015 and 2016 to assess the water vapor flux (FH₂O) and its relationship with other climatic variables. The FH₂O and climatic variables were measured by an eddy covariance system and a micrometeorological observatory. Daily mean FH₂O during the dry seasons of 2015 and 2016 were 0.009-0.092 g m^-2 s^-1 and 0.014-0.101 g m^-2 s^-1, respectively. Seasonal average FH₂O was 14.6% higher in 2016 than that in 2015. Diurnal variation for FH₂O showed a bell-shaped curve with its peak at 13:30-14:00 Indian Standard Time (IST) in both the years. Carbon dioxide flux was found higher with rise in FH₂O. This relationship was stronger at higher vapor pressure deficit (VPD) (20 ≤ VPD ≤ 40 and VPD > 40 hPa). The FH₂O showed significant positive correlation with latent heat flux, net radiation flux, photosynthatically active radiation, air, water and soil temperatures, shortwave down and upwell radiations, maximum and minimum temperatures, evaporation, and relative humidity in both the years. Principal component analysis showed that FH₂O was very close to latent heat flux in both the years (Pearson correlation coefficient close to 1). The two-dimensional observation map of the principal component F1 and F2 showed the observations taken during the vegetative stage and panicle initiation stage, and flowering stage and maturity stage were closer to each other. It can be concluded that the most important climatic variables controlling the FH₂O were latent heat of vaporization, net radiation, air temperature, soil temperatures, and water temperature.