Foam fractionation of globular proteins

Foam fractionation of bovine serum albumin (BSA) was studied as a model system for potato wastewater. The effects of feed concentration, superficial gas velocity, feed flow rate, bubble size, pH, and ionic strength on the enrichment and recovery of BSA were investigated in a single-stage continuous foam fractionation column. Enrichments ranged from 1.5 to 6.0 and recoveries from 5 to 85%. The feed concentrations were varied from 0.01 to 0.2 wt %, and enrichments were found to increase with lower feed concentrations. Enrichments also increased with lower superficial gas velocities and larger bubble sizes. At sufficiently low feed flow rates, enrichment was found to increase with an increase in the flow rate, eventually becoming insensitive to the feed flow rate at higher values. The pH was varied from 3.5 to 7.0 and ionic strength from 0.001M to 0.2M. The effects of pH and ionic strength were found to be coupled with bubble size. A minimum bubble size was found at pH 4.8, the isoelectric point of BSA, resulting in a minimum in the enrichment. Bubble size, and thus enrichment, was found to increase as the ionic strength decreased from 0.2M to 0.01M. Previous models(1,2) for the hydrodynamics of foam column were extended for a singlestage continuous foam fractionation column for the prediction of enrichment and recovery. The model assumed adsorption equilibrium, infinite surface viscosity, and bubbles of the same size. Though coalescence was formally accounted for in the model by considering bubble size as a function of foam height, calculations for the experimental runs were performed only for the case of no coalescence. Quantitative predictions of enrichment and recovery could not be made with a single representative bubble size because of the broad inlet bubble size distribution as well as broadening of the distribution as a result of coalescence. The experimental enrichments were higher and recoveries were lower than the model predictions, the discrepancy being more pronounced at lower feed concentrations because of increased coalescence. The higher enrichments are due to the predominant effect of internal reflux as a result of coalescence whereas the lower recoveries are a result of detrimental effects of broadening bubble size distributions.     

Ventricular Dyssynchrony Patterns in Left Bundle Branch Block,With and Without Heart Failure

Background

Assessment of ventricular dyssynchrony in patients with heart failure is used for selecting candidates for cardiac resynchronization therapy (CRT). The patterns of regional distribution of dyssynchrony in a population with LBBB with and without heart failure have not been well delineated. This aspect forms the object of the study.

Methods

Tissue Doppler Imaging (TDI) data of consecutive patients with heart failure and LBBB (Group A) was compared with those with LBBB and normal LV function (Group B). All patients had standard 2D-echocardigraphic examination and TDI. Tissue velocity curves obtained by placing sample volumes in opposing basal and mid segments of septal, lateral, inferior, anterior and posterior walls were analyzed. Inter ventricular dyssynchrony (IVD) was assessed by the difference between aortic and pulmonary pre ejection intervals. LV dyssynchrony (LVD) was assessed by the difference in times to peak velocity. A delay of ≥ 40 msec was considered significant for presence of IVD and LVD.

Results

There were 103 patients in Group A and 25 in Group B. The mean QRS duration and PR intervals respectively were 146 ± 25 vs. 152±20 msec and 182± 47 vs. 165±36 msec. (p=NS) LVEF in the 2 groups were (32 ± 6 % vs. 61± 11%; p< 0.01). Prevalence of dyssynchrony in the HF group compared to Group B was 72% vs. 16%, (P< 0.01). Lateral wall dyssynchrony in the 2 groups was 37% vs. 0% (p< 0.01) while septal dyssynchrony was 16% vs. 16% (p- NS).

Conclusions

72% of heart failure patients with LBBB have documented dyssynchrony on TDI, which has a heterogeneous regional distribution. Dyssynchrony may be seen in LBBB and normal hearts but it is does not involve the lateral wall. Septal dyssynchrony in heart failure patients may not have the same significance as lateral wall delay.     

Use of a novel pacing mode to achieve biventricular pacing in a patient with recurrent atrial lead dislodgement after CRT-D implantation

Cardiac resynchronization therapy device (CRT-P and CRT-D) implantation has increased tremendously with increasing operator experience, eligible patients and expansion of indications. Refinements in devices and algorithms now aid physicians to improve biventricular pacing and optimize CRT. We report a case in which an interesting device program was used to achieve biventricular pacing after repeated dislodgement of the atrial lead in a patient implanted with CRT-D.     

Linkage analysis of three families with arrythmogenic right ventricular cardiomyopathy in India

BACKGROUND:

Arrythmogenic Right Ventricular Cardiomyopathy (ARVC) is a primary myocardial disorder morphologically characterized by subtle to severe replacement of the right ventricular myocardium by fatty and fibrous tissue. ARVC is known to be highly prevalent in European population with recent reports implicating it to be a major cause of sudden death in young individuals even from American and Asian population.

AIM:

To implicate or exclude TMEM43 (ARVC-5), DSP(ARVC-8) genes and the yet to be identified gene at ARVC-6 locus in the pathogenesis in three families affected with ARVC from India.

MATERIALS AND METHODS:

Three families comprising of 42 affected/unaffected members were included in the study. Three microsatellite markers, D3S3613 (ARVC5) D10S1664 (ARVC6), D6S309 (ARVC8) were genotyped by PCR-based native PAGE. Two-point Linkage analysis was performed using LINKAGE program version 5.2

RESULTS AND DISCUSSION:

LOD scores from linkage analysis for the microsatellite marker D10S1664 (ARVC-6) in families KS and REV have shown positive value hinting the involvement of this locus in the etiology of ARVC, while linkage analysis in the SB family ruled out involvement of DSP, TMEM43 and ARVC-6, as negative LOD scores were obtained with all three loci. Therefore, linkage analysis carried out in the present study indicates that ARVC-6 (cumulative LOD score is equal to plus 1.203376 at θ is equal to 0.05) could be the locus harboring the mutated gene in two out of three families.     

Consensus statement for implantation and follow-up of cardiac implantable electronic devices in India

Cardiac implantable electronic device (CIED) procedures are being done by many operators/centers and it is projected that this therapy will remarkably increase in India in the coming years. This document by IHRS, aims at guiding the Indian medical community in the appropriate use and method of implantation with emphasis on implanter training and center preparedness to deliver a safe and effective therapy to patients with cardiac rhythm disorders and heart failure.     

Kinetics of adsorption of globular proteins at an air-water interface.

Adsorption of globular proteins at an air-water interface from an infinite stagnant medium was modeled as one-dimensional diffusion in a potential field. The interaction potential experienced by an adsorbing molecule consisted of contributions from electrostatic interactions, work done against the surface pressure to clear area at the interface in order to anchor the adsorbed segments, and the change in the free energy due to exposure of penetrated surface hydrophobic functional groups to air. The assumption of irreversible adsorption is employed in the present analysis. The energy barrier to adsorption, present at sufficiently large surface pressures, was found to be higher for smaller surface hydrophobicities, larger surface pressures, larger size molecules, and oblate orientation of an ellipsoidal molecule. Consequently, more adsorption occurred at larger surface hydrophobicities, smaller size molecules, and for prolate orientation of ellipsoidal molecules. The subphase concentration has been shown to be zero at short times, increasing with time at larger times, and eventually becoming close to the bulk concentration as a result of increasing energy barrier to adsorption. The predicted evolution of surface concentration with time for adsorption of lysozyme at an air-water interface agreed well with the experimental data of Graham and Phillips (1979a).     

A low prevalence of MYH7/MYBPC3 mutations among Familial Hypertrophic Cardiomyopathy patients in India

Familial Hypertrophic Cardiomyopathy (FHC) is an autosomal dominant disorder affecting the cardiac muscle and exhibits varied clinical symptoms because of genetic heterogeneity. Several disease causing genes have been identified and most code for sarcomere proteins. In the current study, we have carried out clinical and molecular analysis of FHC patients from India. FHC was detected using echocardiography and by analysis of clinical symptoms and family history. Disease causing mutations in the β-cardiac myosin heavy chain (MYH7) and Myosin binding protein C3 (MYBPC3) genes were identified using Polymerase Chain Reaction-Deoxyribose Nucleic Acid (PCR-DNA) sequencing. Of the 55 patient samples screened, mutations were detected in only nineteen in the two genes; MYBPC3 mutations were identified in 12 patients while MYH7 mutations were identified in five, two patients exhibited double heterozygosity. All four MYH7 mutations were missense mutations, whereas only 3/9 MYPBC3 mutations were missense mutations. Four novel mutations in MYBPC3 viz. c.456delC, c.2128G>A (p.E710K), c.3641G>A (p.W1214X), and c.3656T>C (p.L1219P) and one in MYH7 viz. c.965C>T (p.S322F) were identified. A majority of missense mutations affected conserved amino acid residues and were predicted to alter the structure of the corresponding mutant proteins. The study has revealed a greater frequency of occurrence of MYBPC3 mutations when compared to MYH7 mutations.