Combined Endo Research Articles

Efficacy of Chlorhexidine Intracanal Medicament on Periodontal Healing in Concomitant Endodontic-Periodontal Disease with Communication: A Randomized Clinical Trial

Background: Chlorhexidine has been extensively used in various periodontal and endodontic infections. However its use in combined endo perio lesion has not been defined clearly. The aim of this study was to evaluate the efficacy and synergistic effect of chlorhexidine intra canal medicament with combination of comprehensive periodontal therapy in endodontic periodontal lesions. 
 Materials and Methods: The patients were randomly assigned group 1 and group 2. Both the groups were treated by phase 1 and phase 2 periodontal treatments while group 1patients received conventional root canal treatment and group 2 patients were treated by chlorhexidine intracanal medicament for 6 months. The primary outcome measures are probing pocket depth, relative attachment level and bleeding on probing. 
 Results: Both groups showed improvement on primary outcome measures. However, group 2 showed significant more reduction in probing pocket depth (PPD) and bleeding on probing (BOP) and gain in relative attachment level (RAL) after complete 6 months treatment with chlorhexidine. Postoperative measurements from group1 and group 2 showed reductions in mean PPD of 2.63±0.98 and 3.57±1.13 mm, mean BOP reduction of 76.78±31.41and 87.54±22.35 and mean RAL gains of 2.42±1.27 and 3.42±0.94 mm, respectively. 
 Conclusion: 2% CHX gel used as an intracanal medicament along with periodontal treatment demonstrated more favourable treatment response in terms of periodontal healing.

Combined endo- and epicardial pace-mapping to localize ventricular tachycardia isthmus in ischaemic and non-ischaemic cardiomyopathy.

A high-density pace-mapping can depict an abrupt transition in paced QRS morphology from a poor to excellent match, unmasking the critical component of ventricular tachycardia (VT) isthmus from the entrance to exit. We sought to assess pace-mapping at multiple sites within the endo- and epicardial scars to identify the VT isthmus in patients with ischaemic (ICM) and non-ischaemic cardiomyopathy (NICM). Colour-coded maps correlating to the percentage matches between 12-lead electrocardiograms during VT and pace-mapping [referred to as correlation score maps (CSMs)] were analysed. We studied 115 CSMs (80 endo- and 35 epicardial CSMs) in 37 patients (17 ICM, 20 NICM). The CSM with an abrupt change (AC) in pacemap score (AC-type) on the endocardium was more frequently observed in ICM than in NICM [11/39 (28%) vs. 1/41 (2%); P = 0.001]. Among 35 CSMs that were analysed by the combined endo- and epicardial mapping, 10 (29%) CSMs exhibited non-AC-type on the endocardium; however, AC-type was present on the opposite epicardium. Although 24 (69%) CSMs did not show AC-type on both the endocardium and epicardium, 16 of them had either an excellent (>90%) or poor (<0%) correlation score on either side, associated with isthmus exit or entrance, respectively. However, the remaining eight CSMs had neither excellent nor poor scores. The CSM may provide electrophysiological information to localize the endo- and epicardial VT isthmus. The absence of AC-type CSM on the endocardium, which is frequently observed in NICM, appears to indicate the sub-epicardial or intramural course of the critical isthmus.

Epicardial ablation of ventricular tachycardia in patients with structural heart disease: a single-centre experience over 12 years.

Epicardial ablation has risen to an essential part of the treatment of ventricular tachycardias (VTs). In this study, we report the efficacy, risks, and current trends of epicardial ablation in structural heart disease as reported in a tertiary single centre over a 12-year period. Two hundred and thirty-six patients referred for VT ablation underwent a successful epicardial access and were included in the analysis (89% non-ischaemic cardiomyopathy, 90% males, mean age 60 years, mean left ventricular ejection fraction 38.4%). After performing epicardial ablation the clinical VTs were eliminated in 87% of the patients and 71% of the cohort achieved freedom from VT during 22-month follow-up. Twelve patients (5%) suffered major procedure-related complications. Until the end of follow-up 47 (20%) patients died, 9 (4%) underwent a left ventricular assist device implantation and 10 (4%) patients received a heart transplantation. Antiarrhythmic drugs at baseline and during follow-up were independent predictors of VT recurrence. Atrial fibrillation, renal dysfunction, worse New York Heart Association class, and antiarrhythmic drugs at follow-up were associated with worse survival in our cohort. In this large tertiary single-centre experience, percutaneous epicardial access was feasible in the large majority of the cohort with acceptably low complications rates. A combined endo-/epicardial approach resulted in 87% acute and 71% long-term success. Further studies are needed to clarify the role of routine combined endo-/epicardial ablation in these complex cardiomyopathies.

Inappropriate sinus tachycardia: a review.

Inappropriate sinus tachycardia (IST) has been defined as a resting heart rate of >100 beats per minute and an average 24-hour heart rate >90 bpm with distressing symptoms resulting from the persistent tachycardia. IST is prevalent in 1% of the middle-aged population, mostly females. Rarely can elderly patients also present with IST. Possible mechanisms of IST include intrinsic sinus node abnormality, beta-adrenergic receptor stimulating autoantibody, beta-adrenergic receptor supersensitivity, muscarinic receptor autoantibody, or hyposensitivity, impaired baroreflex control, depressed efferent parasympathetic/vagal function, nociceptive stimulation, central autonomic overactivity, aberrant neurohumoral modulation, etc. Symptoms associated with IST are palpitations, chest pain, fatigue, shortness of breath, presyncope, and syncope. Despite these distressing symptoms, IST has not been associated with tachycardia-associated cardiomyopathy or increased major cardiovascular events. Various treatment options for patients with IST are ivabradine, beta-adrenergic blockers, calcium channel blockers, psychiatric evaluation, and exercise training. Although, endocardial radiofrequency ablation targeting the sinus node has been used as a treatment modality for otherwise treatment-refractory IST, the results have been dismal. The other modalities used for refractory IST treatment are endocardial modification of the sinus node using radiofrequency energy, combined endo and epicardial ablation of the sinus node, thoracoscopic epicardial ablation of the sinus node, sinus node sparing thoracoscopic and endocardial hybrid ablation. The goal of this review is to provide the readership with the pathophysiological basis of IST and its management options.

Combination of cryothermy with radiofrequency energy sources during hybrid atrial fibrillation ablation- impact on lesion quality and outcomes

Abstract Background Whereas pulmonary vein isolation lays the groundwork of endocardial atrial fibrillation (AF) ablation, it leaves patients undertreated. Additional substrate modification of the left atrium is often required, but lesion gaps and non-transmurality limit restoration of sinus rhythm. Moreover, some low voltage areas and conduction abnormalities are located exclusively on the epicardial aspect, and endocardial ablation alone does not address these issues. Our hybrid endo-/epicardial ablation strategy overcomes all these shortcomings. Purpose To test if the combination of epicardial cryo and radiofrequency (RF) ablation (dual) further improves the quality of ablation lines, and if the combined endo-/epicardial ablation can treat intractable cases of AF. Methods Twenty-six patients (13 paroxysmal, 13 long-persistent; 20 patients with 1–5 prior endocardial AF ablations) first underwent epicardial, total thoracoscopic beating heart ablation (TTA). Lesion sets included bilateral PVI, left atrial appendage closure, as well as superior (roof) and inferior (floor) interpulmonary vein lines. Roof and floor lines were alternatingly ablated by dual energy or RF only. Three months post TTA, endocardial mapping with optional gap closure completed this two-stage hybrid concept. Results Intraoperatively, 24 of 40 (60%) previous left or right endocardial PVIs were found incomplete. Apart from two post-TTA pacemaker insertions and one mini-thoracotomy for bleeding, respectively, no major morbidity was observed during follow up. The full protocol of the hybrid concept was applied in 24 patients. Forty-five of 47 (96%) epicardial PVIs were found gap-less during endocardial mapping, and the remaining 2 PVIs were readily re-ablated. In contrast, only 32 of 46 (70%) roof and floor lines were complete, and endocardial touch up was required in one of three patients. Of note, dual energy lines were more likely to be complete than RF only lines (17 of 22, 77%, vs. 15 of 24, 62%; p NS). Among 19 patients with continuous monitoring, only 4 (21%) had any AF burden including two patients within blanking period and before endocardial gap closure. The remaining 7 patients without continuous monitoring never experienced any symptoms related to recurrent AF, and serial Holter EKG were without pathology. Conclusions Hybrid ablation and dual energy provides a strong armamentarium for extra-pulmonary venous triggers of AF. Linear ablation lines were more likely to be gap-less and transmural, if dual energy sources were used. Dual energy TTA is highly efficient to restore sinus rhythm in patients with prior failed endocardial AF ablation. However, one of three patients will require endocardial gap closure to realize the full benefit of our two-stage hybrid concept. Further study will evaluate if dual energy lines outside the box can improve outcome in these challenging cases of intractable AF. Funding Acknowledgement Type of funding source: None

Overcoming challenges in the management of arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) appears in most patients to be an inherited disease characterized by fibrofatty replacement of myocytes extending from the epicardium to the endocardium in the right ventricle. The disease process results in life‑threatening ventricular arrhythmias and ventricular dysfunction. In the absence of a gold‑standard diagnostic test and despite the progress in imaging techniques, ARVC is often misdiagnosed and earlier detection of the disease is challenging. Preprocedural identification and localization of the substrate can be determined from the analysis of surface electrocardiography and cardiac magnetic resonance imaging. Typically, perivalvular arrhythmogenic substrate, defined by electroanatomic mapping, is present and can be isolated to the epicardium. Ablation targets are further identified with activation, entrainment, and local electrogram abnormalities based on detailed electroanatomic mapping. Extensive combined endo / epicardial ablation performed in experienced centers is frequently required to prevent ventricular tachycardia (VT). Catheter ablation significantly reduces recurrences of VT, appropriate implantable cardioverter‑defibrillator shocks, and the use of antiarrhythmic drugs and cardiac transplant as a management strategy for refractory arrhythmias is rarely required. Progression of the disease is poorly understood and may require a distinct triggering mechanism. Biventricular involvement is more common than previously recognized. However, left ventricular involvement leading to significant terminal heart failure is fortunately uncommon and left ventricular tachycardias are also infrequent. Many questions remain regarding prevention and management of coexisting tricuspid valve regurgitation, atrial arrhythmias, and intracardiac thrombosis. Although data on genotype‑phenotype correlations is growing, long‑term follow‑up studies of families with ARVC are still lacking. Ongoing research will contribute to better understanding of this pathological condition.

Catheter Ablation of Ventricular Tachycardia in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: A Sequential Approach.

BackgroundIt has been suggested that endocardial and epicardial ablation of ventricular tachycardia (VT) improves outcome in arrhythmogenic right ventricular cardiomyopathy/dysplasia. We investigated our sequential approach for VT ablation in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia in a single center.Methods and ResultsWe included 47 patients (44±16 years) with definite (81%) or borderline (19%) arrhythmogenic right ventricular cardiomyopathy/dysplasia between 1998 and 2016. Our ablation strategy was to target the endocardial substrate. Epicardial ablation was performed in case of acute ablation failure or lack of an endocardial substrate. Single and multiple procedural 1‐ and 5‐year outcome data for the first occurrence of the study end points (sustained VT/ventricular fibrillation, heart transplant, and death after the index procedure, and sustained VT/ventricular fibrillation for multiple procedures) are reported. Eighty‐one radiofrequency ablation procedures were performed (mean 1.7 per patient, range 1–4). Forty‐five (56%) ablation procedures were performed via an endocardial, 11 (13%) via an epicardial, and 25 (31%) via a combined endo‐ and epicardial approach. Complete acute success was achieved in 65 (80%) procedures, and partial success in 13 (16%). After a median follow‐up of 50.8 (interquartile range, [18.6; 99.2]) months after the index procedure, 17 (36%) patients were free from the primary end point. After multiple procedures, freedom from sustained VT/ventricular fibrillation was 63% (95% CI, 52–75) at 1 year, and 45% (95% CI, 34–61) at 5 years, with 36% of patients receiving only endocardial radiofrequency ablation. A trend (log rank P=0.058) towards an improved outcome using a combined endo‐/epicardial approach was observed after multiple procedures.ConclusionEndocardial ablation can be effective in a considerable number of arrhythmogenic right ventricular cardiomyopathy/dysplasia patients with VT, potentially obviating the need for an epicardial approach.

Endo-/Epicardial Catheter Ablation of Atrial Fibrillation

Until today, catheter interventional mapping and ablation of atrial fibrillation (AF) has been limited to the right and left atrial endocardium. We report feasibility, electrophysiological findings, and clinical outcome using a combined endo-/epicardial catheter approach for mapping and ablation of AF. Fifty-nine patients with permanence of pulmonary vein isolation and further symptomatic recurrences of paroxysmal AF, persistent AF, or atrial tachycardia underwent reablation using biatrial endo-/epicardial mapping and ablation. Identification of arrhythmia substrates and selection of ablation strategy were based on sinus rhythm voltage mapping. Using continuous monitoring and a 3-month blanking period, freedom from AF/atrial tachycardia ≥2 minutes was defined as primary end point. In all patients, endo-/epicardial mapping and ablation was feasible using standard technologies of catheter access, 3-dimensional mapping, and radiofrequency ablation. Epicardial mapping and ablation did not add procedural risks. Exclusively epicardial low voltage substrates were found in 14% of the patients. For the first time, novel epicardial conduction abnormalities located in the epicardial fiber network were described in human AF patients (19% of the cohort). Epicardial ablation was needed in 80% of the patients. Over 23±10 months of follow-up freedom from arrhythmia recurrences measured 73%. Catheter-based endo-/epicardial mapping and ablation of AF was feasible and safe. Epicardial mapping provided new insights into AF mechanisms. Epicardial ablation increased transmurality of ablation lesions. Clinical outcome in this cohort of complex AF patients was favorable, indicating potential further development of current AF treatment.

Myocardial wall thinning predicts transmural substrate in patients with scar-related ventricular tachycardia

Scar-related ventricular tachycardia (VT) arises from specific substrate according to etiology. The purpose of this study was to evaluate the relationship between wall thinning (WT) on multidetector computed tomography (MDCT) and local abnormal ventricular activity (LAVA) in patients with ischemic cardiomyopathy (ICM), postmyocarditis (PMC), and dilated cardiomyopathy (DCM). Forty-two patients (40 male, age 58 ± 13 years, 22 ICM, 11 PMC, 9 DCM) underwent MDCT before a combined endo-/epicardial VT ablation procedure. WT (<5 mm) and severe wall thinning (SWT) (<2 mm) area on MDCT were compared to the prevalence of endo-/epicardial LAVA during sinus rhythm. WT and SWT were found on MDCT in 36 (86%) and 20 (48%) with 42 ± 37 cm2 and 26 ± 24 cm2, respectively. SWT was frequently detected in ICM (ICM 77% vs PMC 27% vs DCM 0%, P <.001). LAVA were frequently observed on the endocardium in ICM and on the epicardium in PMC. Endo-/epicardial facing LAVA were frequently found within SWT areas (91% in <2 mm, 9% in 2-5 mm, and 0% in >5 mm, P < .001). In SWT areas, the presence of endocardial LAVA in ICM and epicardial LAVA in PMC predicted opposite facing LAVA with sensitivity and specificity of 78% and 48% and 79% and 98%, respectively. SWT predicted epicardial LAVA in ICM and endocardial LAVA in PMC with sensitivity and specificity of 89% and 100%, and 100% and 100%, respectively. SWT is frequently found in ICM and PMC but is not common in DCM. SWT predicts LAVA on the opposite side of the wall (epicardial in ICM and endocardial in PMC), indicating transmural VT substrate. MDCT is useful for identifying VT substrate and helpful for understanding the mechanisms of the location of VT substrate domain.

Can ventricular tachycardia non-inducibility after ablation predict reduced ventricular tachycardia recurrence and mortality in patients with non-ischemic cardiomyopathy? A meta-analysis of twenty-four observational studies

BackgroundAt present, the role of ventricular tachycardia (VT) non-inducibility after ablation in patients with non-ischemic cardiomyopathy (NICM) remains controversial. We conducted a meta-analysis of the published literature to assess whether VT non-inducibility after ablation could predict reduced VT recurrence and mortality in patients with NICM. MethodsPubMed, ScienceDirect, and the Cochrane library were searched for studies evaluating the effects of VT non-inducibility after catheter ablation on the long-term outcome in NICM patients with sustained VT. Results were analyzed using a fixed-effect model, and the data were pooled using RevMan 5.3 software. ResultsTwenty-four observational studies were identified (736 participants, mean follow-up time: 22months). NICM patients with VT inducibility after ablation had a higher risk of VT recurrence (odds ratio [OR]=5.83, 95% confidence interval [CI] 4.07–8.37; P<0.00001) and all-cause mortality (OR=3.55, 95% CI 1.62–7.78; P=0.002) compared with VT non-inducibility. Similarly in the subgroup analysis, patients with VT inducibility showed a higher risk of VT recurrence from non-ischemic dilated cardiomyopathy (OR=3.92, 95% CI 2.36–6.50; P<0.00001) and arrhythmogenic right ventricular dysplasia/cardiomyopathy (OR=5.37, 95% CI 2.20–13.10; P=0.0002). Additionally, meta-analysis also showed that combined endo–epicardial ablation significantly reduced the risk of VT recurrence compared with endocardial-only ablation (OR=2.02, 95% CI 1.19–3.44; P=0.009; mean follow-up time: 22months). ConclusionRecent evidence has shown that VT non-inducibility after ablation is a predictor for reduced VT recurrence and mortality compared with VT inducibility in NICM patients with sustained VT. In addition, endocardial plus adjuvant epicardial ablation provides better long-term arrhythmia-free survival than endocardial ablation alone.

Insights into Catheter Ablation of Ventricular Tachycardias in Arrhythmogenic Right Ventricular Cardiomyopathy / Dysplasia

Arrhythmogenic right ventricular cardiomyopathy/ dysplasia (ARVC/D), mostly affecting young/middle-aged individuals, poses a significant risk of malignant ventricular arrhythmias (VAs) and subsequent sudden cardiac death (SCD). Antiarrhythmic agents (AAA) provide insufficient arrhythmia suppression and prevention and can be proarrhythmic. Thus, the implantable cardioverters-defibrillator (ICD) is considered the first-line treatment, especially in patients with secondary prevention indication. Nevertheless, catheter ablation is an additional therapy to the ICD which has proved its efficacy in primary and secondary prevention of fatal arrhythmias and sudden cardiac death. The superiority of the combined endo- and epicardial VT ablation in this population is clear since the ARVC/D substrate has been shown to be mostly epicardial. Due to progressive nature of ARVC/D, ablation seems to be a useful tool for the patients who experience recurrent VT episodes or electrical storms.

Imaging and epicardial substrate ablation of ventricular tachycardia in patients late after myocarditis

We present clinical, electroanatomical mapping (EAM), imaging, and catheter ablation (CA) strategies in patients with myocarditis-related ventricular tachycardia (VT). Between January 2010 and July 2012, 26 consecutive patients underwent imaging-guided CA of myocarditis-related ventricular arrhythmias, 23 of 26 using a combined endo-epicardial approach. Segment per segment correspondence of late enhanced (LE) scar localization with EAM scar was assessed in all patients with available uni/bipolar maps (n = 19). Induced VTs were targeted prior to substrate modification. Late potentials (LPs) abolition constituted a procedural endpoint independently from VT inducibility. Clinical monomorphic VT was induced in 15 of 26 patients (57.7%) and was associated with epicardial LPs in 10 of 15, completely abolished in 7 of 10 patients. Of the 10 patients rendered non-inducible VTs were ablated epicardially in 7. Late potentials were also detected in 7 of 11 initially non-inducible patients and completely abolished in 4. After a median follow-up of 23 (15-31) months, 20 of 26 patients (76.9%) remained free from VT recurrence. Bipolar mapping revealed low-voltage scar (<1.5 mV) in 1 patient endocardially and in 14 of 19 epicardially. Unipolar mapping revealed low-voltage scar (<8 mV) in 12 of 19 patients endocardially and in 18 of 19 epicardially. Correspondence of LE scar localization with endocardial bipolar scar was 1%, with endocardial unipolar scar 23.7%, with epicardial bipolar scar 39.8%, and with epicardial unipolar scar 66.2%. Pre-procedural scar imaging and EAM findings support the necessity of an epicardial approach in patients with prior myocarditis. Epicardial unipolar mapping (<8 mV) is superior in scar identification and CA based on substrate modification is safe and effective in this setting.

Combined endo and epicardial substrate ablation (scar dechanneling) in arrhythmogenic cardiomyopathy: a prospective multicenter study

Background: Ventricular tachycardia (VT) ablation in patients with arrhythmogenic cardiomyopathy (AC) has a high rate of recurrence. Recent studies suggest that a more extensive epicardial arrhythmogenic substrate could explain these results. We report the results of combined endocardial and epicardial susbtrate VT ablation (using the dechanneling technique) in patients with AC. Methods and results: Thirty-two consecutive patients with AC and VT (mean 14±8 VT episodes/patient) were included in 9 centers. Six patients (19%) had left-dominant AC. A high-density endo (372±152 sites mapped) and epicardial (523±299 sites) electroanatomical voltage map was obtained during sinus rhythm. Electrograms with delayed components (E-DCs) were tagged and classified as entrance or inner conducting channels (CCs) points, depending on the delayed component precocity. The procedural endpoint was the isolation of all identified CCs firstly, by discrete ablation at CC entrance, and the abolition of residual inducible VTs afterwards. The mean procedure and fluoroscopy time were 215±80 min and 18±7 min, respectively. Epicardial maps showed larger scars (94±81 cm2 vs. 18±22 cm2, p<0.01) and more E-DCs (68±56 vs. 13±16, p<0.01) in both right and left-dominant AC. Nine (28%) patients showed neither scar nor E-DCs at endocardium. A mean of 26±10 RF applications were required. Non-inducibility of the clinical VT and of any monomorphic VT was achieved in 100% and 93.5% of patients respectively. Iatrogenic pericardial effusion requiring pericardiocentesis occurred in one patient. During a median follow-up of 20 months (IQR 6-32 months), 5 (16%) patients suffered any VT episode. Three patients required a redo procedure. After redo procedures 91% of patients remained without VT recurrence. Conclusion: Arrhythmogenic substrate in AC is mainly epicardial. These findings support the use of a combined endo and epicardial substrate guided approach for the catheter ablation of VT in AC patients.

The Evolution of Minimally Invasive Colorectal Surgery Combined Endoscopic–Laparoscopic Approaches

Patients with benign colon polyps that are not amenable to endoscopic removal traditionally have undergone colon resection. Although endoscopic mucosal and submucosal dissection has been described for these polyps, the technique is not widely available and does not provide a solution for certain polyps. Polyp removal using combined endo–laparoscopic techniques may be an effective alternative in select patients.

Effect of global ischemia and reperfusion during ventricular fibrillation in myopathic human hearts

The effect of lack of global coronary perfusion on myocardial activation rate, wavebreak, and its temporal progression during human ventricular fibrillation (VF) is not known. We tested the hypothesis that global myocardial ischemia decreases activation rate and spatiotemporal organization during VF in myopathic human hearts, while increasing wavebreak, and that a short duration of reperfusion can restore these spatiotemporal changes to baseline levels. The electrograms were acquired during VF in a human Langendorff model using global mapping consisting of two 112-electrode arrays placed on the epicardium and endocardium simultaneously. We found that global myocardial ischemia results in slowing of the global activation rate (combined endo and epi), from 4.89+/-0.04 Hz. to 3.60+/-0.04 Hz. during the 200 s of global ischemia (no coronary flow) (P<0.01) in eight myopathic hearts. Two minutes of reperfusion contributed to reversal of the slowing with activation rate value increasing close to VF onset (4.72+/-0.04 Hz). In addition, during the period of ischemia, an activation rate gradient between the endocardium (3.76+/-0.06 Hz) and epicardium (3.45+/-0.06 Hz) was observed (P<0.01). There was a concomitant difference in wavebreak index (that provides a normalized parameterization of phase singularities) between the epicardium (11.29+/-2.7) and endocardium (3.25+/-2.7) during the 200 s of ischemia (P=0.02). The activation rate, gradient, and wavebreak changes were reversed by short duration (2 min) of reperfusion. Global myocardial ischemia of 3 min leads to complex spatiotemporal changes during VF in myopathic human hearts; these changes can be reversed by a short duration of reperfusion.

Endodontic Periodontic Lesions and Host Modulation – Case Series

Host modulation, includes inhibition of matrix metalloproteinases, blocking production of proinflammatory cytokines and inhibition of osteoclastic activity, has therapeutic value as adjunctive therapy in treating chronic periodontitis. This case series presented three patients with chief complaint of teeth mobility where endo perio involvement was diagnosed. The endo perio combined lesions generally shows the communication between pulp and periodontal tissues with the same origin of dental infection. Diagnosis in such cases is difficult and generally raising problem in the management. All of the cases were managed by non surgical endodontic therapy combined with host modulation. All local factors causing the lesion were removed. Clinical outcome after six and nine months were quite satisfactory. Combined endo perio cases are challenging to the dentists and involve multidisciplinary involvement. To manage such cases, dentists have to rely on the unconventional techniques. DOI: 10.14693/jdi.v22i1.378

Component analysis of the X-C-Y anomeric effect (X = O, S; Y = F, OMe, NHMe) by DFT molecular orbital calculations and natural bond orbital analysis

Six 2-Y-substituted oxacyclohexane and thiacyclohexane heterocycles (Y = F, OMe, NHMe) were examined using DFT molecular orbital calculations. Natural bond orbital (NBO) analysis of the total energy behaviour yielded the orbital-interaction factors contributing to the conformational equilibria. The dipole moments of the optimized systems were used to estimate the electrostatic contributions to the anomeric effect. The primary determinant of the X-C-Y anomeric effect was found to be the orbital interaction components associated with the combined endo- and exo-anomeric effects acting in concert in the axial conformers. Electrostatic interactions made a contribution to the observed conformer stabilization in all cases, but did not account for the relative magnitudes of the energy differences among conformers of homologous molecules. In the case of the methylamino substituent, accentuated steric interactions in the axial conformer precluded stabilization by the exo-anomeric interaction and consequently, the net endo/exo anomeric stabilization did not dominate the conformational equilibria.Key words: anomeric effect, component analysis, natural bond orbital analysis, electrostatic, steric, and orbital interaction effects.

Cathepsin B: an alternative protease for the generation of an aggrecan ‘metalloproteinase’ cleavage neoepitope

Previously, only matrix metalloproteinases were believed capable of cleaving the cartilage proteoglycan, aggrecan, between Asn341 and Phe342, to yield a small G1 fragment terminating in the residues VDIPEN. We show that the combined endo- and exopeptidase activities of the cysteine protease, cathepsin B, also generate this epitope, suggesting that it should no longer be considered as an exclusive marker of metalloproteinase activity.

Enzymatic Degradation of Single Crystals of Bacterial and Synthetic Poly(β-hydroxybutyrate)

Lamellar single crystals of both natural poly[(R)-β-hydroxybutyrate], PHB, and synthetic poly[(R,S)-β-hydroxybutyrate] of various tacticities were degraded using enzymes isolated from the fungus Aspergillus fumigatus and the bacterium Pseudomonas lemoignei. Degradation was monitored by both turbidimetric and titrimetric assays. Despite their highly ordered state, single crystals of bacterial PHB were observed to degrade completely; no decrease in molecular weight was observed in the partly degraded polymer. By contrast, the single crystals of synthetic PHB showed only partial degradation, with some decrease in molecular weight; faster and more substantial degradation was observed for the most isotactic material, whereas single crystals from a nearly atactic sample were essentially inert. These results differ from those found for PHB films, implying that tacticity response is linear when crystallinity effects have been normalized. The observed results are consistent with preferential degradation from the crystal edges rather than the chain folds of the lamellar surface and support the hypothesis of a combined endo−exo degradation mechanism for these two depolymerases.