Left bundle branch pacing lead for sensing ventricular arrhythmias in implantable cardioverter-defibrillator: A pilot study (LBBP-ICD study)

BACKGROUND

Left bundle branch pacing (LBBP) has been suggested as an alternative modality for biventricular pacing in cardiac resynchronization therapy (CRT)-eligible patients. As it provides stable R-wave sensing, LBBP has been recently used to provide sensing of ventricular arrhythmia in patients receiving implantable cardioverter-defibrillator (ICD) with CRT.

OBJECTIVE

The aim of this study was to analyze the long-term safety and efficacy of the LBBP lead for appropriate detection of ventricular arrhythmia and delivery of antitachycardia pacing (ATP) in patients requiring defibrillator therapy with CRT.

METHODS

CRT-eligible patients who underwent successful LBBP-optimized ICD and LBBP-optimized CRT with defibrillator were enrolled. The LBBP lead was connected to the right ventricular-P/S port after capping the IS-1 connector plug of the DF-1-ICD lead. LBBP-optimized ICD or LBBP-optimized CRT with defibrillator was decided on the basis of correction of conduction system disease. Documented arrhythmic episodes and therapy delivered were analyzed.

RESULTS

Thirty patients were enrolled. The mean age was 59.7 ± 10.5 years. LBBP resulted in an increase in left ventricular ejection fraction from 29.9% ± 4.6% to 43.9% ± 11.2% (P < .0001). During a mean follow-up of 22.9 ± 12.5 months, 254 ventricular arrhythmic events were documented. Appropriate events (n = 225 [89%]) included nonsustained ventricular tachycardia (VT) (n = 212 episodes [94%]), VT (n = 8 [3.5%]), and ventricular fibrillation (n = 5 [2.5%]). ATP efficacy in terminating VT was 75%. Eleven percent of episodes (n = 29) were inappropriately detected because of T-wave oversensing. Inappropriate therapy (ATP) was delivered for 14 episodes (5.5%). Three patients (10%) had worsening of tricuspid regurgitation.

CONCLUSION

Sensing from the LBBP lead for arrhythmia detection is safe as ∼90% of the episodes were detected appropriately. Future studies with a dedicated LBBP-defibrillator lead along with algorithms to avoid oversensing can help in combining defibrillation with conduction system pacing.

Is left bundle branch pacing (LBBP) associated with better depolarization and repolarization kinetics than right ventricular mid septal pacing (RVSP)? - Comparison of frontal QRS -T angle in patients with LBBP, RVSP and normal ventricular conduction

AIMS

To assess the frontal QRS- T angle (f QRS- T angle) in patients with left bundle branch pacing (LBBP) as compared to right ventricular mid septal pacing (RVSP) implanted for symptomatic high degree atrioventricular (AV) block and to compare with control subjects with normal ventricular conduction (CSNVC) METHODS: A total of one-fifty subjects were chosen (50 patients with LBBP, 50 patients with RVSP and 50 CSNVC). The indication for pacemaker implantation was symptomatic high degree AV block. Baseline clinical and electrocardiogram (ECG) parameters like QRS duration (QRSD), QRS axis and f QRS-T angle and Ejection Fraction (EF) were assessed. f QRS-T angle was measured as the difference between the computerised mean frontal QRS and T wave axes in the limb leads. If the difference between the QRS axis and T-wave axis exceeds 180°, then the resultant QRS-T angle would be calculated as 360° minus the absolute angle to obtain a value between 0° and 180°. Baseline, immediate post procedural and 6 month follow up (f/u) ECGs and EF were chosen for the analysis.

RESULTS

Patients who underwent LBBP had significantly shorter paced QRSD than patients who had undergone RVSP (112 ± 12 ms vs 146 ± 13 ms; 95 % confidence interval (CI): 43, -31; p<0.001). There was no significant difference in the QRSD before and after LBBP. The QRSD before and after pacing in RVSP was 111 ± 27 ms and 146 ± 13 ms; 95 % CI: 43, -28; p < 0.001. The QRSD in control patients with NVC was 82.94 ± 9.59 ms. RVSP was associated with wider f QRS-T angle when compared with LBBP (103 ± 53° vs 82 ± 43°; 95 % CI: 39, -1.0; p = 0.037). The baseline and immediate post procedure f QRS-T angle in LBBP was 70 ± 48° and 82 ± 43°; 95 % CI: 31, 5.3; p = 0.2. At 6 months f/u, the f QRS-T angle was 61 ± 43°; 95 % CI: 8.5, 35; p=0.002. The baseline and immediate post procedure f QRS-T angle in RVSP was 67 ± 51° and 103 ± 53°; 95 % CI: 54, -17; p < 0.001. At 6 months f/u, the f QRS-T angle in RVSP group was 87 ± 58°; 95 % CI: 2.6, 29; p = 0.020. The f QRS T angle in control patients with NVC was 24 ± 16°. When subgroup analysis was done the difference in the f QRS-T angle was significant between RVSP and LBBP groups only in patients who had wide QRS escape. The mean LVEF at 6-month follow-up in LBBP vs RVSP was 61 ± 3.7 % vs 57.1 ± 7.8 %; 95 % CI:1.48, 6.32, p = 0.002. In the RVSP group, three patients developed pacing induced cardiomyopathy (PIC) whereas no patients in the LBBP group developed PIC at 6-month follow-up; p=0.021. One patient with PIC had deterioration of functional status with new onset HF symptoms. The patient symptoms improved with medical therapy and needed no hospitalisation. The patient declined further interventions including upgradation to CRT or LBB pacing. No deaths or ventricular arrhythmias were observed during the study period.

CONCLUSION

LBBP is associated with narrower f QRS-T angle as compared to RVSP both at post implant period and at 6 month f/u period. These findings might be due to the more physiological depolarization and repolarization kinetics associated with LBBP. RVSP was associated with 6 % incidence of PIC. Hence wide f QRS-T angle might be a predictor of PIC.

Systematic review and meta-analysis of early aortic valve replacement versus conservative therapy in patients with asymptomatic aortic valve stenosis with preserved left ventricle systolic function

BACKGROUND

A quarter of patients with severe aortic stenosis (AS) were asymptomatic, and only a third of them survived at the end of 4 years. Only a select subset of these patients was recommended for aortic valve replacement (AVR) by the current American College of Cardiology/American Heart Association guidelines. We intended to study the effect of early AVR (eAVR) in this subset of asymptomatic patients with preserved left ventricle function.

METHODS AND RESULTS

We searched PubMed and Embase for randomised and observational studies comparing the effect of eAVR versus conservative therapy in patients with severe, asymptomatic AS and normal left ventricular function. The primary outcome was all-cause mortality. The secondary outcomes were composite major adverse cardiac events (MACE) (study defined), myocardial infarction (MI), stroke, cardiac death, sudden death, the development of symptoms, heart failure hospitalisations and major bleeding. We used GRADEPro to assess the certainty of the evidence. In the randomised controlled trial (RCT) only analysis, we found no significant difference in all-cause mortality between the early aortic intervention group versus the conservative arm (CA) (incidence rate ratio, IRR (CI): 0.5 (0.2 to 1.1), I2=31%, p=0.09). However, in the overall cohort, we found mortality benefit for eAVR over CA (IRR (CI): 0.4 (0.3 to 0.7), I2=84%, p<0.01). There were significantly lower MACE, cardiac death, sudden death, development of symptoms and heart failure hospitalisations in the eAVR group. We noticed no difference in MI, stroke and major bleeding.

CONCLUSION

We conclude that there is no reduction in all-cause mortality in the eAVR arm in patients with asymptomatic AS with preserved ejection fraction. However, eAVR reduces heart failure related hospitalisations and death or heart failure hospitalisations.

PROSPERO REGISTRATION NUMBER

CRD42022306132.

Right sided approach for left bundle branch pacing using lumen-less lead: Technical considerations and follow-up outcome

INTRODUCTION

Left bundle branch pacing has gained significant momentum in the last few years. The procedure involves deploying the lead deep inside the interventricular septum through left subclavian vein. We aimed at analyzing the feasibility, efficacy and long-term outcome of left bundle branch pacing (LBBP) using lumen-less lead through the right subclavian vein.

METHODS

This was a retrospective-institutional, single center observational study done in consecutive patients who underwent LBBP using 3830 selectsecuretm lead. Left subclavian venous access was the primary strategy for lead implantation. Patients requiring right sided approach due to venous obstruction or persistent left superior-vena-cava (PLSVC) for LBBP were included in the study.

RESULTS

Right sided approach was successful in 16 out of 19 (84%) attempted patients. C315-His catheter was used in all patients without modifying its curvature. PLSVC (n = 7), left venous obstruction (n = 7), right sided device upgradation (n = 1) and left pocket infection (n = 1) were the reasons for right sided approach. Mean follow-up duration was 17 ± 12 months. LBBP resulted in reduction in QRS duration from 137.3 ± 37.8 ms to 122.3 ± 9.5 ms (p -.13) and increase in LV ejection fraction from 46.2 ± 16.3% to 54.4 ± 11.6% (p -.11). The mean fluoroscopy duration and radiation dose were significantly high in right sided approach (n = 16) as compared to left sided approach (n = 293). In patients requiring cardiac-resynchronization therapy (CRT), right sided LBBP resulted in reduction in QRS duration from 171.8 ± 18.5 to 125.5 ± 11.9 ms (p -.0001) and increase in LVEF from 29.1 ± 3.8 to 45.1 ± 11.9% (p -.005).

CONCLUSION

Right sided LBBP is feasible, safe and effective in patients requiring pacing for symptomatic bradyarrhythmia and CRT. Further development in dedicated tools for right-sided approach would help in reducing the fluoroscopy-duration and radiation-dose.

MAgnetic resonance imaging based DUal lead cardiac Resynchronization therapy: A prospectIve Left Bundle Branch Pacing Study (MADURAI LBBP study)

BACKGROUND

Cardiac resynchronization therapy(CRT) is a class-I indication for LVEF≤35%, and heart failure(HF). LBBB associated nonischemic-cardiomyopathy (LB-NICM) with minimal or no scar by cardiac-magnetic-resonance(CMR) imaging may be associated with excellent prognosis following CRT. Left-bundle-branch-pacing(LBBP) can achieve excellent resynchronization in LBBB patients.

OBJECTIVES

Aim of our study was to prospectively assess feasibility and efficacy of LBBP with or without a defibrillator in patients with LB-NICM and LVEF ≤35%, risk stratified by CMR.

METHODS

Pts with LB-NICM, LVEF≤35% and HF were prospectively enrolled from 2019 to 2022. If the scar burden<10% by CMR, LBBP only (Group-I) and if ≥10%, LBBP+ICD(Group-II) was performed. Primary endpoints-1.Echocardiographic-response(ER)- ΔLVEF ≥15% at 6 months; 2.Composite of time to death, HFH or sustained VT/VF. Secondary endpoints-1.Echocardiographic-hyper-response(EHR-LVEF≥50%orΔLVEF ≥20%) at 6 and 12 months; 2.Indication for ICD-upgradation(persistent LVEF<35% at 12 months or sustained VT/VF) RESULTS: 120 patients were enrolled. CMR showed <10% scar-burden in 109 patients(90.8%). 4 patients opted for LBBP+ICD and withdrew. LBBP optimized-dual-chamber-pacemaker(LOT-DDD-P) was done in 101 patients and LOT-CRT-P in 4 patients(Group-I,n=105). Scar-burden ≥10% in 11 pts who underwent LBBP+ICD(Group-II). During mean-follow-up 21±12 months, primary endpoint of ER observed in 80%(68/85 pts) in Group-I vs 27%(3/11 pts) in Group-II(p-0.0001). Primary composite-endpoint of death,HFH or VT/VF occurred in 3.8% in group-I vs 33.3% in Group-II(p<0.0001). Secondary endpoint of EHR(LVEF≥50%) observed in 39.5%vs0%, 61.2%vs9.1% and 80%vs33.3% at 3, 6 and 12 months in group-I and group-II respectively.

CONCLUSION

CMR guided CRT using LOT-DDD-P appears to be a safe and feasible approach in LB-NICM and has the potential to reduce healthcare cost.

Left bundle branch pacing-optimized implantable cardioverter-defibrillator (LOT-ICD) for cardiac resynchronization therapy: A pilot study

Left bundle branch pacing (LBBP) involves direct capture of left bundle fibers by placing the lead deep inside the interventricular septum. Several studies have shown the feasibility and efficacy of LBBP as an alternative modality for cardiac resynchronization therapy (CRT). This paper describes approach for providing cost effective CRT with defibrillator (CRT-D) by LBBP and dual chamber implantable cardioverter defibrillator (ICD) which we label as LBBP optimized ICD (LOT-ICD). LBBP was performed using C315 sheath and 3830 Selectsecure lead in all patients by premature ventricular complex guided approach. In patients with complete correction of conduction system disease, IS-1 connector plug of the IS-1/DF-1 lead was capped and 3830 lead connected to the dual chamber ICD pulse-generator at RV-P/S port. LOT-ICD provided stable R-wave sensing for arrhythmia monitoring and resulted in cost-effective resynchronization therapy at reduced fluoroscopy duration and radiation dose.

Trans-radial approach versus trans-femoral approach in patients with acute coronary syndrome undergoing percutaneous coronary intervention: An updated meta-analysis of randomized controlled trials

Introduction

Trans-radial approach (TRA) is recommended over trans-femoral approach (TFA) in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). We intended to study the effect of access on all-cause mortality.

Methods and results

We searched PubMed and EMBASE for randomized studies on patients with ACS undergoing PCI. The primary outcome was all-cause mortality at 30-days. The secondary outcomes included in-hospital mortality, major adverse cardiac or cerebrovascular event (MACE) as defined by the study, net adverse clinical event (NACE), non-fatal myocardial infarction, non-fatal stroke, stent thrombosis, study-defined major bleeding, and minor bleeding, vascular complications, hematoma, pseudoaneurysm, non-access site bleeding, need for transfusion, access site cross-over, contrast volume, procedure duration, and hospital stay duration. We studied 20,122 ACS patients, including 10,037 and 10,085 patients undergoing trans-radial and trans-femoral approaches, respectively. We found mortality benefit in patients with ACS for the trans-radial approach [(1.7% vs. 2.3%; RR: 0.75; 95% CI: 0.62–0.91; P = 0.004; I2 = 0%). Out of 10,465 patients with STEMI, 5,189 patients had TRA and 5,276 had TFA procedures. A similar benefit was observed in patients with STEMI alone [(2.3% vs. 3.3%; RR: 0.71; 95% CI: 0.56–0.90; P = 0.004; I2 = 0%). We observed reduced MACE, NACE, major bleeding, vascular complications, and pseudoaneurysms. No difference in re-infarction, stroke, and serious bleeding requiring blood transfusions were noted. We noticed a small decrease in contrast volume(ml) {mean difference (95% CI): −4.6 [−8.5 to −0.7]}, small but significantly increase in procedural time {mean difference (95% CI) 1.2 [0.1 to 2.3]}and fluoroscopy time {mean difference (95% CI) 0.8 [0.3 to1.4] min} in the trans-radial group.

Conclusion

TRA has significantly reduced 30-day all-cause mortality among patients undergoing PCI for ACS. TRA should be the preferred vascular access in patients with ACS.

Design, synthesis, cytotoxic, and anti-inflammatory activities of some novel analogues of aloe-emodin isolated from the rhizomes of Rheum emodi

In connection with our continuous efforts in the synthesis of derivatives from major compounds isolated from traditional medicinal plants, in the present study we have attempted to synthesize the furan-conjugated aloe-emodin derivatives (5a-j) using a three-component reaction. The synthesized derivatives were assessed for anticancer activity against five different cancer cell lines using the in vitro MTT assay and the results showed that most of the derivatives are potent against cancer cells comparing with the control. Compounds 5a and 5e showed excellent activity against all the cancer cells with less than 12.5 µM and arrested the cell cycle at the G0/G1 phase in both CAL27 and SCC9 cells. Compound 5e induces the early apoptosis in CAL27 cells and compounds 5a and 5e induce early and late apoptosis, respectively, in SCC9 cells. Moreover, compounds 5b, 5c, 5i, and 5j showed excellent anti-inflammatory activity in LPS-stimulated RAW 264.7 cells by inhibiting IL-6 production. The molecular docking studies revealed that compound 5e has strong interaction with the CLK kinase and protein kinase II through hydrogen binding Asp325 and Lys290.

Impact of plaque burden and composition on coronary slow flow in ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention: intravascular ultrasound and virtual histology analysis

AIM

Coronary slow flow (SF) is an important complication of percutaneous coronary intervention (PCI) associated with poor prognosis. The aim was to assess grey-scale intravascular ultrasound (IVUS) and virtual histology (VH-IVUS) characteristics of culprit lesion in ST-elevation myocardial infarction (STEMI).

METHODS

A total of 295 consecutive patients with STEMI underwent coronary angiogram and IVUS. Following PCI, patients divided into two groups; SF (thrombolysis in myocardial infarction [TIMI] flow  ≤ 2, n = 74) and normal flow (NF) (TIMI flow >2, n = 221). Coronary plaque burden and its composition in relation to SF were evaluated.

RESULTS

On grey-scale IVUS, the plaque area (12.3 mm² vs. 11.5 mm², p = .01), plaque volume (110.7 mm³ vs. 99.8 mm³, p < .001), lesion external elastic membrane (EEM) cross-sectional area (14.9 mm² vs. 14.0 mm², p = .011) and remodelling index (1.3 vs. 1.2, p = .043) were significantly higher in SF group. On VH-IVUS, absolute fibrous volume (48.1 mm³ vs. 41.5 mm³, p ≤ .001), fibrofatty volume (23.8 mm³ vs. 18.6 mm³, p = .015), necrotic core volume (8.3 mm³ vs. 5.5 mm³, p < .001), dense calcium volume (1.2 mm³ vs. 0.6 mm³, p = .003) and thin cap fibroatheroma either single (30.1% vs. 16.1%, p < .001) or multiple (9.6% vs. 1.8%, p < .001) were higher in SF arm. In multivariable analysis, absolute necrotic core volume (odds ratio  =  1.159; 95% CI 1.030-1.305, p = .015) was the only independent predictor of SF.

CONCLUSIONS

Higher necrotic core volume as detected by VH-IVUS may be a potential risk factor for the development of coronary SF phenomenon in patients with STEMI after PCI.

Arrhythmia in Children and Adolescents and Outcome of Radiofrequency Ablation for Tachyarrhythmias - A Single Center Experience Over 16 Years

OBJECTIVE

Radiofrequency (RF) ablation for tachycardia in children poses challenges in view of slender veins and delicate cardiac structures in close proximity.

METHODS

We reviewed hospital records for patients below 18 years,who underwent RF ablation from August, 2001 to February, 2017 at a single hospital.

RESULTS

Among 214 patients (134 males, age12.5 (4.6) years), there were 221 tachycardia substrates: accessory pathways in 85 patients (39%), AV nodal re-entrant tachycardia in 79 patients (36%), ventricular tachycardia in 28 patients (13%) and atrial tachycardia in 21 patients (9.6%).The overall success rate of RF ablation was 95% (204/214). Success rate in those younger than 6 years was similar to those in older age groups. There were no major complication.

CONCLUSIONS

RF ablation below 18 years of age has a high success rates and low complications.

Association of culprit lesion plaque characteristics with flow restoration post-fibrinolysis in ST-segment elevation myocardial infarction: an intravascular ultrasound-virtual histology study

Background

Not every patient achieves normal coronary flow following fibrinolysis in STEMI (ST-segment elevation myocardial infarction). The culprit lesion plaque characteristics play a prominent role in the coronary flow before and during percutaneous coronary intervention. The main purpose was to determine the culprit lesion plaque features by virtual histology-intravascular ultrasound (VH-IVUS) in patients with STEMI following fibrinolysis in relation to baseline coronary angiogram TIMI (thrombolysis in myocardial infarction) flow. Pre-intervention IVUS was undertaken in 61 patients with STEMI after successful fibrinolysis. After the coronary angiogram, they were separated into the TIMI1–2 flow group (n = 31) and TIMI 3 flow group (n = 30). Culprit lesion plaque composition was evaluated by VH-IVUS.

Results

On gray-scale IVUS, the lesion external elastic membrane cross-sectional area (EEM CSA) was significantly higher in the TIMI 1–2 groups as compared to the TIMI 3 group (15.71 ± 3.73 mm² vs 13.91 ± 2.94 mm², p = 0.041) with no significant difference in plaque burden (82.42% vs. 81.65%, p = 0.306) and plaque volume (108.3 mm³ vs. 94.3 mm³, p = 0.194). On VH-IVUS, at the minimal luminal area site (MLS), the fibrous area (5.83 mm² vs. 4.37 mm², p = 0.024), necrotic core (NC) area (0.95 mm² vs. 0.59 mm², p < 0.001), and NC percentage (11% vs. 7.1%, p = 0.024) were higher in the TIMI 1–2 groups in contrast to the TIMI 3 group. The absolute necrotic core (NC) volume (8.3 mm³ vs. 3.65 mm³, p < 0.001) and NC percentage (9.3% vs. 6.0%, p = 0.007) were significantly higher in the TIMI 1–2 groups as compared to the TIMI 3 group. Absolute dense calcium (DC) volume was higher in TIMI 1–2 groups with a trend towards significance (1.0 mm³ vs.0.75 mm³, p = 0.051). In multivariate analysis, absolute NC volume was the only independent predictor of TIMI 1–2 flow (odds ratio = 1.561; 95% CI 1.202–2.026, p = 0.001). Receiver operating characteristic curves showed absolute NC volume has best diagnostic accuracy (AUC = 0.816, p < 0.001) to predict TIMI 1–2 flow with an optimal cutoff value of 4.5 mm³ with sensitivity and specificity of 79% and 61%, respectively.

Conclusions

This study exemplifies that the necrotic core component of the culprit lesion plaque in STEMI is associated with the coronary flow after fibrinolysis. The absolute necrotic core volume is a key determinant of flow restoration post-fibrinolysis and aids in prognostication of less than TIMI 3 flow.

Comparison of Intravascular Ultrasound Virtual Histology Parameters in Diabetes versus Non-Diabetes with Acute Coronary Syndrome

INTRODUCTION

The progression and pattern of coronary atherosclerosis in diabetes mellitus (DM) is different from non-DM, leading to a higher rate of vascular complications in DM.

OBJECTIVE

This study aims to assess and compare the high-risk plaque characteristics in the culprit artery of DM and non-DM patients with acute coronary syndrome (ACS) using virtual histology intravascular ultrasound (VH-IVUS).

METHODS

A total of 158 ACS patients were included, 63 of whom were known to have DM. IVUS analysis was done in the de novo target vessel and culprit lesion for which percutaneous coronary intervention was planned. Culprit lesions with a visual-estimate angiographic stenosis of <70% were excluded.

RESULTS

The mean age of patients was 52.4 ± 11.6 years. The study group comprised 82% men, 31% with hypertension, and 39.87% with DM. No significant difference was observed between the DM and non-DM groups in relation to quantitative IVUS parameters like lesion length, minimal lumen area, and plaque area. However, there was a significant difference in VH-IVUS parameters like higher necrotic core and dense calcium in the DM patients than in the non-DM patients (p < 0.01). The occurrence of VH-derived thin-cap fibroatheroma (VH-TCFA) in the culprit vessel was significantly higher in the DM group than in the non-DM group (25.3 vs. 5.2%; p < 0.01). Positive vessel-wall remodeling was noted in both groups without any significant difference (p = 0.74).

CONCLUSION

The DM patients had high-risk plaque composition features like a higher necrotic core, which is a marker of plaque vulnerability. Thus, aggressive medical therapy targeting vascular inflammation using high-dose statins would help in the stabilization of unstable plaque morphology and the reduction of major cardiovascular events.

Cardiac resynchronization therapy device implantation in a patient with persistent left superior vena cava without communicating innominate vein - should we proceed from the same side? - A dilemma revisited

Persistent left superior vena cava (PLSVC) is an uncommon congenital anomaly. We report a case of implantation of cardiac resynchronization therapy - pacemaker (CRT-P) device in a 38-year-old lady with idiopathic dilated cardiomyopathy. After left axillary vein puncture, we faced an unexpected entry of left subclavian to PLSVC draining into the coronary sinus (CS). The target posterolateral vein which had been identified before, seemed to have an acute angle at its entry into the CS. Hence, at this stage we were in a dilemma, whether to switch to the right side or to continue from the same side. We continued the procedure from the left side and completed it successfully after some manipulation and improvisation.

Enhanced antimicrobial, antioxidant and anticancer activity of Rhizophora apiculata: An experimental report

The present study is designed to evaluate the antimicrobial, antioxidant and anticancer activities of Rhizophora apiculata. Initially, the phenolic and flavonoid content was quantified in solvent extracts, and gallic acid and rutin were used as a control, respectively. Further, antimicrobial and minimal inhibitory activities of different solvent extracts were assessed against human clinical pathogenic bacteria, and the results showed that butanol and methanol extract has potential antimicrobial activity. FTIR analysis of solvent extracts showed the presence of phenolic compounds at 3409-3430 cm^-1 that actively involved in various applications including antioxidant and anticancer activities. The in vitro antioxidant activity of solvent extracts showed excellent antioxidant potential, about 84% of DPPH free-radical scavenging, 76% of hydrogen peroxide, 82% of hydroxyl radical scavenging, and 80% of reducing power. Two-way ANOVA analysis showed that the highly significant effect of antioxidant activity depends on the concentration of extracts. The DNA protection efficiency of extracts against oxidative damage was confirmed by DNA nicking assay using bacterial DNA. The methanol extract effectively inhibited the growth and induces the apoptosis through ROS generation and sensitizes the mitochondrial membrane potential of A549 lung cancer cells. Taken together, the results showed that the solvent extracts of R. apiculata could be potential antioxidant and anticancer agents.

Biogenic gold nanoparticles induce cell cycle arrest through oxidative stress and sensitize mitochondrial membranes in A549 lung cancer cells

Schematic representation of biogenic synthesized AuNPs have been proven to have excellent anticancer activity against A549 human lung cancer cells.

Antioxidant activity of 1-hydroxy-1-norresistomycin derived from Streptomyces variabilis KP149559 and evaluation of its toxicity against zebra fish Danio rerio

Extraction of bioactive compounds from marine actinomycetes and its antimicrobial activity.

Correction: Development of glycolipid biosurfactant for inducing apoptosis in HeLa cells

Correction for ‘Development of glycolipid biosurfactant for inducing apoptosis in HeLa cells’ by V. Ramalingam et al., RSC Adv., 2016, 6, 64087–64096.

Development of glycolipid biosurfactant for inducing apoptosis in HeLa cells

A novel glycolipid biosurfactant produced fromStaphylococcus aureuswas used to induce apoptosis in HeLa cells.

Effect of mercuric chloride on circulating hormones in adult albino rats

The effect of mercuric chloride at two different doses, 0.5 mg/kg body weight (low dose), 1 mg/kg body weight (high dose), for 30 days, was seen on the circulating hormones in the mature male albino rats. Testosterone level was markedly decreased in the low dose (P < 0.01) and high dose (P < 0.001) treated animals. The level of luteinizing hormone (LH) was also reduced in the low dose (P < 0.01) as well as in the high dose (P < 0.001) treated animals. However, follicle stimulating hormone (FSH) and prolactin (PRL) levels were found to be decreased only in the high dose (P < 0. 05) treated animals and no change was observed in the low dose treated animals. The changes in the hormone levels caused by the mercuric chloride treatment suggest the dysfunction of pituitary-testicular axis.

Effect of mercuric chloride on membrane-bound enzymes in rat testis

AIM

To study the effect of mercuric chloride on the membrane-bound enzymes.

METHODS

The effect of mercuric chloride at two different doses, 1 mg/kg (low dose) and 2 mg/kg (high dose), orally for 30 days, was observed on the membrane-bound enzymes in the testis of adult albino rats.

RESULTS

Mercuric chloride significantly decreased the body weight and testis weight in the high dose group (P< 0.05), but not in the low dose group. The activities of 5'nucleotidase and adenosine triphosphatases were markedly decreased (P< 0.01) in the testis of both groups. Alkaline phosphatase and ggr-glutamyl transferase activities were significantly increased (P< 0.01) in both groups. However, the effect was more pronounced in the high than in the low dose groups.

CONCLUSION

The dose dependent effect of mercuric chloride on these enzymes may affect the membrane characteristics and thereby the fertility of the animal.

Preliminary crystallographic studies of the ligand-binding domain of the thyroid hormone receptor complexed with triiodothyronine

A truncated, recombinant form of the thyroid hormone receptor, including the hormone binding domain, has been co-crystallized with the hormone T3. The crystals are monoclinic, most likely space group P2, with two molecules per asymmetric unit and cell dimensions a = 63.6 A, b = 80.8 A, c = 100.9 A and beta = 92.1 degrees. The crystals diffract to only medium resolution and decay rapidly in the X-ray beam using laboratory sources. By contrast, high resolution, high-quality data are obtained using synchrotron radiation in conjunction with cryocrystallography.

Structure of a bacterial enzyme regulated by phosphorylation, isocitrate dehydrogenase

The structure of isocitrate dehydrogenase [threo-DS-isocitrate: NADP+ oxidoreductase (decarboxylating), EC 1.1.1.42] from Escherichia coli has been solved and refined at 2.5 A resolution and is topologically different from that of any other dehydrogenase. This enzyme, a dimer of identical 416-residue subunits, is inactivated by phosphorylation at Ser-113, which lies at the edge of an interdomain pocket that also contains many residues conserved between isocitrate dehydrogenase and isopropylmalate dehydrogenase. Isocitrate dehydrogenase contains an unusual clasp-like domain in which both polypeptide chains in the dimer interlock. Based on the structure of isocitrate dehydrogenase and conservation with isopropylmalate dehydrogenase, we suggest that the active site lies in an interdomain pocket close to the phosphorylation site.