Septal Venous Channel Perforation during Left Bundle Branch Area Pacing: A Prospective Study.

OBJECTIVES: To characterize the diagnosis, frequency, and procedural implications of septal venous channel perforation during left bundle branch area pacing (LBBAP). METHODS: All consecutive patients undergoing LBBAP over an 8-month period were prospectively studied. During lead placement, obligatory septal contrast injection was performed twice, at initiation (implant entry zone) and completion (fixation zone). An intuitive fluoroscopic schema using orthogonal views (LAO/RAO) and familiar landmarks is described. Using this, we resolved zonal distribution (I-VI) of lead position on the ventricular septum and its angulation (post-fixation angle θ). Subjects with/without septal venous channel perforation were compared. RESULTS: Sixty-one-patients [Male 57.3%, Median Age (IQR) 69.5(62.5-74.5) years] were enrolled. Septal venous channel perforation was observed in 8 (13.1%) patients [Male 28.5%, Median Age (IQR) 64(50-75) years]. They had higher frequency of, i) right-sided-implant (25% vs. 1.9%, p = 0.04), ii) fixation in zone III at the mid-superior septum (75% vs 28.3%, p = 0.04), iii) steeper angle of fixation- median θ (IQR) [19(10-30)° vs. 5(4-19)°, p = 0.01), and iv) longer median penetrated-lead-length (IQR) [13(10-14.8) vs. 10(8.5-12.5)mm, p = 0.03]. Coronary sinus drainage of contrast was noted in 5 (62.5%) patients. Abnormal impedance drops during implantation (12.5% vs. 5.7%, p = NS) were not significantly different. CONCLUSION: When evaluated systematically, septal venous channel perforation may be encountered commonly after LBBAP. The fiducial reference framework described using fluoroscopic imaging identified salient associated findings. This may be addressed with lead repositioning to a more inferior location and are not associated with adverse consequence acutely or in early follow-up.

P-type ATPase zinc transporter Rv3270 of Mycobacterium tuberculosis enhances multi-drug efflux activity.

Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis, in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis. Overexpression of Rv3270 increased the tolerance of host cells to norfloxacin, ofloxacin, sparfloxacin, ampicillin, oxacillin, amikacin and isoniazid. A significantly lower accumulation of norfloxacin, ethidium bromide, bocillin FL and levofloxacin in cells harbouring Rv3270 as compared to host cells indicated its role in enhancing efflux activity. Although over-expression of Rv3270 did not alter the susceptibility levels of levofloxacin, rifampicin and apramycin, the presence of a sub-inhibitory concentration of Zn2+ resulted in low-level tolerance towards these drugs. Of note, the expression of Rv3270 enhanced the biofilm-forming ability of the host cells strengthening its role in antimicrobial resistance. Therefore, the study indicated that the over-expression of Rv3270 enhances the drug efflux activity of the micro-organism where zinc might facilitate drug-metal cross-resistance for some antibiotics.

A case of exaggerated exuberance: Iatrogenic atrioventricular block/intra-Hisian Wenckebach during conduction system pacing.

Isolated sinus node dysfunction with its pursuant long-term risk for atrioventricular (AV) conduction disease poses a unique dilemma for proponents of CSP due to paucity of imprimatur guidelines. In such scenarios, the risk and prognosis of iatrogenic AV block is not well elucidated but is a valid concern. We report a case where CSP was complicated by iatrogenic AV block and peculiarly the rare phenomenon of intra-Hisian Wenckebach.

An unusual site of ablation for a ventricular tachycardia.

Scar-related ventricular tachycardia (VT) ablation involves localizing the critical isthmuses by overdrive pacing maneuvers and three-dimensional activation mapping. Implantable prosthetic devices have been known to complicate this by covering sites of potential isthmuses. We herein present a sentinel report of scar-VT ablation with a protected isthmus localized over an endothelialized post-myocardial infarction ventricular septal defect occluder device.

Silencing ANGPTL8 reduces mouse preadipocyte differentiation and insulin signaling.

ANGPTL8, expressed mainly in the liver and adipose tissue, regulates the activity of lipoprotein lipase (LPL) present in the extracellular space and triglyceride (TG) metabolism through its interaction with ANGPTL3 and ANGPTL4. Whether intracellular ANGPTL8 can also exert effects in tissues where it is expressed is uncertain. ANGPTL8 expression was low in preadipocytes and much increased during differentiation. To better understand the role of intracellular ANGPTL8 in adipocytes and assess whether it may play a role in adipocyte differentiation, we knocked down its expression in normal mouse subcutaneous preadipocytes. ANGPTL8 knockdown reduced adipocyte differentiation, cellular TG accumulation and also isoproterenol-stimulated lipolysis at day 7 of differentiation. RNA-Seq analysis of ANGPTL8 siRNA or control siRNA transfected SC preadipocytes on days 0, 2, 4 and 7 of differentiation showed that ANGPTL8 knockdown impeded the early (day 2) expression of adipogenic and insulin signaling genes, PPARγ, as well as genes related to extracellular matrix and NF-κB signaling. Insulin mediated Akt phosphorylation was reduced at an early stage during adipocyte differentiation. This study based on normal primary cells shows that ANGPTL8 has intracellular actions in addition to effects in the extracellular space, like modulating LPL activity. Preadipocyte ANGPTL8 expression modulates their differentiation possibly via changes in insulin signaling gene expression.

Open window mapping for redo accessory pathway ablation in Ebstein anomaly.

Accessory pathway ablation in Ebstein anomaly can be significantly more challenging than in structurally normal hearts. An alternative to the conventional approach to mapping APs is to detect points with a high-density mapping catheter based on an automated detection algorithm using open window mapping. It detects the sharpest signal at each point with high-density mapping rather than relying on the origin of the local electrogram to localize the pathway and determine a site for successful ablation. We herein report the first case in literature of a redo-accessory pathway ablation in Ebstein anomaly using this technique.

Relevant parameters for laser surgery of soft tissue.

In recent years, the laser has become an important tool in hospitals. Laser surgery in particular has many advantages. However, there is still a lack of the understanding of the influence of the relevant parameters for laser surgery. In order to fill this gap, the parameters pulse frequency, use of an exhaustion system, air cooling, laser power, laser scan speed, laser line energy and waiting time between cuts were analysed by ANOVA using inter-animal variation as a benchmark. The quality of the cuts was quantized by a previously published scoring system. A total of 1710 cuts were performed with a [Formula: see text] laser. Of the parameters investigated, laser power and scan speed have the strongest influence. Only the right combination of these two parameters allows good results. Other effects, such as the use of pulsed or continuous wave (CW) laser operation, or air cooling, show a small or negligible influence. By modulating only the laser power and scan speed, an almost perfect cut can be achieved with a [Formula: see text] laser, regardless of the external cooling used or the laser pulse duration or repetition rate from CW to nanosecond pulses.

Budd-Chiari syndrome in children: Radiological intervention and role of shear wave elastography in monitoring response.

OBJECTIVES: Radiological intervention (RI) is the preferred treatment in children with Budd-Chiari syndrome (BCS). We studied the comparative long-term outcome of BCS children, with and without RI and utility of liver and splenic stiffness measurement (LSM, SSM) by 2-dimensional shear wave elastography (2D-SWE) in assessing response. METHODS: Sixty children (40 boys, median age 10.5 [6.5-15.25] years) with BCS (29 newly diagnosed, 31 follow-up) were evaluated. LSM and SSM by 2D-SWE and vascular patency were monitored pre- and postprocedure (≥ 6 months postprocedure) in those undergoing RI. Medical therapy without anticoagulation and monitoring was done in subjects without RI. The RI and no-RI groups were compared. RESULTS: Ascites (54,90%), hepatomegaly (56,93%) and prominent abdominal-veins (42,70%), were the commonest features. The majority (46,78%) had isolated hepatic vein block. 44 (73%) cases underwent RI, while 16 (27%) were managed conservatively. Both groups were similar at baseline. Post-RI subjects showed significant improvement in clinical findings, liver functions and portal hypertension. LSM [33 (32-34.5) to 19.2 (18-20.67) kPa] and SSM [54.5 (52.3-57.6) to 28.9 (27.6-30.25) kPa] showed a significant decline from baseline value over a follow-up of 12 (6-13) months. Gradual reduction occurred in the LSM and SSM over 1-5 years, with near-normal LSM [10.2 (9.2-11.5) kPa] and SSM [22.3 (20.5-24.3) kPa] values in patients (n-16) with > 5 years follow-up. Patients without RI showed worsening in LSM and SSM. Hepatopulmonary syndrome and hepatocellular carcinoma developed in 4 (8%) and 1 (1.7%) cases respectively. CONCLUSION: RI leads to clinical recovery and reduction with near normalization of LSM and SSM over long-term follow-up in children with BCS. 2D-SWE is a promising tool to monitor outcomes.

The MSMEG_1586 of M. smegmatis Is a Penicillin-Interactive Enzyme That Can Potentially Hydrolyse Aztreonam and Cephalosporins.

Mycobacteria are intrinsically resistant to beta-lactams as they possess several putative penicillin-interactive enzymes (PIEs), some of those are with dual-activity, namely DD-carboxypeptidase and beta-lactamase. Here, with help of molecular approaches, we elucidated the nature of one such putative PIE, MSMEG_1586, in Mycobacterium smegmatis. The in vivo expression of the membrane-bound form of MSMEG_1586 enhanced the beta-lactam resistance of a beta-lactamase deleted host E. coli strain (AM1OC), particularly for aztreonam (eight-fold) and cephalosporins (8-16 fold). To understand the reason for such elevation of resistance, soluble-form of MSMEG_1586 (sMSMEG_1586) was created by removing signal peptides and partially eliminating the amphipathic helix, and finally, expressed and purified. The purified sMSMEG_1586 was active and manifested a strong penicillin-binding affinity as shown by its ability to bind to fluorescent penicillin (Bocillin-FL). Interestingly, the steady-state kinetics apparently confirmed the hydrolytic ability of sMSMEG_1586 towards cefotaxime and aztreonam where hydrolysing aztreonam is a unique and rare behaviour among the beta-lactamases. However, sMSMEG_1586 was devoid of exerting DD-carboxypeptidase like activity. Finally, in silico analysis of MSMEG_1586 revealed a special folding that resembles class C beta-lactamase, except for the absence of a characteristic R2 loop. Overall, MSMEG_1586 could be categorized as a cephalosporinase with the ability to hydrolyse aztreonam.

Caveats related to conduction system pacing utilizing a proprietary deflectable mapping catheter with a stylet-driven lead.

BACKGROUND: Hitherto, lumen less leads (LLLs) were routinely utilized for conduction system pacing (CSP). We report the largest experience using stylet-driven leads (SDLs) with a deflectable mapping catheter for CSP. METHODS: Patients were prospectively and sequentially enrolled for CSP with SDL between June, 2021 and November, 2022 to (i) a novel deflectable mapping catheter (AgilisHisProTM, Abbott) (Group A) or (ii) a fixed curve sheath (Selectra3D, Biotronik) (Group B) in a 1:1 non-randomized fashion. The primary aim was to evaluate safety, feasibility, and efficacy of the CSP using SDL and deflectable mapping catheter (Group A) while reporting procedural success and intermediate-term follow-up. RESULTS: Seventy-nine patients (59.4%M, mean age 67.2+/-10.6 years) were allocated to either (i) Group A (n = 40) or (ii) Group B (n = 39). In Group A (n = 40, 50% M, mean age 67.2+/-9.5 years, follow-up 210.7 + 25.1days), His bundle pacing (HBP) was the default strategy with left bundle branch area pacing (LBBaP) for bailout. Procedural success with HBP was feasible in 17/40 (42.5%) patients with remaining 23/40 (57.5%) needing LBBaP bailout. After initial learning curve, a manual septal curve was introduced to successfully aid LBBaP in 6/23 (26.1%) cases. Procedural and follow-up parameters did not differ significantly in HBP vs. LBBaP. Head-to-head comparison was not performed between the groups owing to different default protocols (HBP-Group A, Discretionary-Group B). CONCLUSIONS: Use of SDL with single-curve deflectable mapping catheter was safe, feasible and yielded moderate procedural success with HBP and frequently needed a LBBaP bailout strategy. In approximately one-fourth of the latter, an out-of-plane manual septal curve was needed to optimize LBBaP.

ABC superfamily transporter Rv1273c of Mycobacterium tuberculosis acts as a multidrug efflux pump.

Efflux pump-mediated drug resistance in bacteria is a common occurrence effective for the general survival of the organism. The Mycobacterium tuberculosis genome has an abundance of adenosine triphosphate (ATP) dependent cassette transporter genes but only a handful of them are documented for their contribution to drug resistance. In this study, we inspected the potential of an ABC transporter Rv1273c from M. tuberculosis as a multidrug efflux pump and a contributor to intrinsic drug resistance. Expression of Rv1273c in Escherichia coli and M. smegmatis conferred tolerance to various structurally unrelated antibiotics. Lower accumulation of fluoroquinolones in intact E. coli and M. smegmatis cells expressing the transporter implied its active efflux activity. Energy-dependent efflux by Rv1273c was observed in real time using the lipophilic dye Nile Red. Expression of Rv1273c also resulted in an increase in biofilm formation by E. coli and M. smegmatis cells. Overall, the results indicate the possibility that Rv1273c might be a multidrug transporter with a wide substrate range and a probable contributor to biofilm formation.

Isolated unilateral pulmonary artery atresia with contralateral pulmonary artery branch stenosis: A "window" for intervention.

Adult presentation of unilateral pulmonary artery atresia in association with contralateral branch pulmonary stenosis is rare. We present the case of a quadragenarian, who manifested with right ventricular failure and hemoptysis. This report discusses the diagnostic workup and therapeutic options along with a brief overview of the concerned literature.

Guar-Based Injectable Hydrogel for Drug Delivery and In Vitro Bone Cell Growth.

Injectable hydrogels offer numerous advantages in various areas, which include tissue engineering and drug delivery because of their unique properties such as tunability, excellent carrier properties, and biocompatibility. These hydrogels can be administered with minimal invasiveness. In this study, we synthesized an injectable hydrogel by rehydrating lyophilized mixtures of guar adamantane (Guar-ADI) and poly-ß-cyclodextrin (p-ßCD) in a solution of phosphate-buffered saline (PBS) maintained at pH 7.4. The hydrogel was formed via host-guest interaction between modified guar (Guar-ADI), obtained by reacting guar gum with 1-adamantyl isocyanate (ADI) and p-ßCD. Comprehensive characterization of all synthesized materials, including the hydrogel, was performed using nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and rheology. The in vitro drug release study demonstrated the hydrogel's efficacy in controlled drug delivery, exemplified by the release of bovine serum albumin (BSA) and anastrozole, both of which followed first-order kinetics. Furthermore, the hydrogel displayed excellent biocompatibility and served as an ideal scaffold for promoting the growth of mouse osteoblastic MC3T3 cells as evidenced by the in vitro biocompatibility study.

Involvement of the non-active site Residues in the Catalytic Activity of NDM-4 Metallo beta-lactamase.

The rise of New Delhi metallo beta-lactamase (NDM) producing bacteria imposes a significant threat to the treatment of bacterial infections due to their broad spectrum against beta-lactams. The activity of metallo beta-lactamases is affected by active site residues as well as residues near the active site. Therefore, we aimed to identify the amino acid residues around the active site of NDM-4 which influence its function. To achieve that, seven substitution mutations (S191A, D192A, S213A, K216A, S217A, D223A and D225A) of NDM-4 were generated through site-directed mutagenesis. Out of these, expression of NDM-4_D192A and NDM-4_S217A in Escherichia coli cells increased the beta-lactam susceptibility as compared to NDM-4. Further, proteins were purified to assess the effect of substitution mutations on zinc content, in vitro catalytic efficiency, and stability of NDM-4. The catalytic efficiency was reduced for these mutants (D192A and S217A) towards beta-lactam substrates, while the thermal stability remained insubstantial as compared to NDM-4. However, the purified NDM-4_D192A exhibited altered zinc content. In silico studies reveal that these changes might be the outcomes of alterations in hydrogen bonding networks and substrate interactions. Taken together, we infer that the D192 and the S217 residues play a substantial role in the activity of NDM-4.