Biological Pacemakers – A Review

Slow heart rates, due to sinus node disease or atrioventricular conduction block, are a significant problem for many patients. Currently, these patients are treated with electronic pacemakers, which provide effective therapy, but are also associated with many problems. Use of biological pacemakers is an attractive solution to these problems. Approaches for the creation of such pacemakers include either the injection of cells that have pacemaker activity (cell-based approach) or modification of cells in the heart to induce pacemaker activity by delivering genes (gene-based approach). This article reviews the progress in the development of biological pacemakers

Liquid-Liquid Equilibrium of Poly(Ethylene Glycol) 6000 + Sodium Succinate + Water System at Different Temperatures

Phase diagrams and the compositions of coexisting phases of poly(ethylene glycol) (PEG) 6000 + sodium succinate + water system have been determined experimentally at 298.15, 308.15, and 318.15 K. The effects of temperature on the binodal curve and tie lines have been studied. The binodal curves were successfully fitted to a nonlinear equation relating the concentrations of PEG 6000 and sodium succinate, and the coefficients were estimated for the formentioned systems (low AARD, high R2, and low SD). Tie-line compositions were estimated and correlated using Othmer-Tobias and Bancroft equations, and the parameters were reported. The effect of temperature on the phase-forming ability has been studied by fitting the binodal data to a Setschenow-type equation for each temperature. The effective excluded volume (EEV) values were also calculated from the binodal data, and it was found out that the values increased with an increase in the temperature. Furthermore, the effect of MW of PEG on the phase diagram has been studied and verified

Parasystole in a Mahaim Accessory Pathway

AbstractAutomaticity has been described in Mahaim pathways, both spontaneously and during radiofrequency ablation. We describe an unusual case of automatic rhythm from a Mahaim pathway presenting as parasystole. The parasystolic beats were also found to initiate tachycardia, resulting in initial presentation with incessant tachycardia and tachycardia induced cardiomyopathy

Anticonvulsant effect of lercanidipine against pentylenetetrazole induced kindling in mice

Background: Emerging evidence has demonstrated the role of high-voltage -sensitive activated dihydropyridine (L-type, CaV1.x) channels in the development of epilepsy. Based on that we hypothesized that lercanidipine, a dihydropyridine calcium channel blocker, would protect against Pentylenetetrazole (PTZ) induced kindling in mice model of epilepsy.Methods: Kindling was induced in Swiss albino mice with PTZ in subconvulsive dose (30 mg/kg i.p.) thrice a week for nine weeks and the effect was scored using ‘4 point scoring system’. Rechallenging on the 3rd and 10th day with the same dose of PTZ was carried out after the last chronic dose.Results: The data of the present study demonstrated that pretreatment with lercanidipine (½ h before PTZ, in doses of 1 and 3 mg/kg i.p. daily) alone and in combination with diazepam (2mg/kg i.p.) had decreased the incidence and severity of seizure as well as prolonged the onset of kindling in a dose-dependent manner (p <0.05). On rechallenging, lercanidipine resulted in reduction of seizure score (p <0.05) and increased the seizure latency.Conclusions: The present study suggested that lercanidipine offered neuroprotection against PTZ induced kindling in mice

Ventricular Tachycardia in Repaired Double Chambered Right Ventricle - Identification of the Substrate and Successful Ablation

A 35 year old female presented with recurrent ventricular tachycardia 5 years after she had undergone surgical repair of double chambered right ventricle. Electroanatomical mapping showed a localised scar in the apex with double potentials and good pace map. Ablation here resulted in non-inducibility of ventricular tachycardia. We hypothesise that the scarring in the apex is the result of sustained pressure overload and becomes arrhythmogenic similar to the apical scar in patients with mid-ventricular hypertrophic cardiomyopathy

HLA-DR phenotypes and IgG, IgA and IgM antibody responses to Mycobacterium tuberculosis culture filtrate and 30 kDa antigens in pulmonary tuberculosis

The role of HLA-DR genetic make-up on the IgG, IgA and IgM antibody response to Mycobacterium tuberculosis culture filtrate and 30 kDa antigens was studied in pulmonary tuberculosis. The study was carried out in HLA-DR typed active pulmonary tuberculosis (ATB) patients (n = 37), inactive (cured) pulmonary tuberculosis (ITB) patients (n = 79) and normal healthy subjects (NHS; n = 46). In ATB and ITB (cured) patients, IgG antibody (optical density at 490 nm for 1 : 3200 dilution) as measured by enzyme-linked immunosorbent assay was the predominant one than IgA and IgM antibodies. Increased IgG antibody titre to culture filtrate (P = 0.03) and decreased titre to 30 kDa antigen were observed with HLA-DR1-positive ATB patients than non-DR1 (ATB) patients. Moreover, HLA-DR4- and HLA-DR6-positive ATB patients showed trends toward an increased IgG antibody response to 30 kDa antigen than HLA-DR4- and HLADR6- negative (ATB) patients respectively. Significantly increased IgA antibody to 30 kDa antigen was observed with HLA-DR1-positive ATB patients than non-DR1 patients (P = 0.03). The study suggests that multiple HLA-DR molecules may regulate the IgG and IgA antibody responses to various proteins of M. tuberculosis. Moreover, HLA-DR phenotypes and increased IgG and IgA antibody titres may be useful to differentiate M. tuberculosis-infected subjects from normal subjects and cured patients with the same HLA-DR phenotypes or genetic make-up