69 research outputs found
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Succesful Radiofrequency Ablation of Atrial Tachycardia Arising From Within the Coronary Venous Sinus
Focal atrial tachycardia (AT) though a relatively uncommon cause of supraventricular
tachycardia is difficult to control with antiarrythmic drugs. With the advent of radiofrequency
ablation (RFA), this form of tachycardia can be treated with high long-term success [1]. These
foci tend to cluster at specific anatomic locations. In the right atrium, these foci occur along the
crista terminalis, the tricuspid annulus, the ostium of the coronary sinus and the perinodal region.
In the left atrium, foci occur predominantly at the pulmonary vein ostia and less commonly at
the mitral annulus, the left atrial appendage, and the left side of interatrial septum [2-6].
We report the electrophysiological characteristics and ablation procedure of a focal atrial
tachycardia which was arising from deep within the coronary sinus
Thermal effects on electron-phonon interaction in silicon nanostructures
Raman spectra from silicon nanostructures, recorded using excitation laser
power density of 1.0 kW/cm^2, is employed here to reveal the dominance of
thermal effects at temperatures higher than the room temperature. Room
temperature Raman spectrum shows only phonon confinement and Fano effects.
Raman spectra recorded at higher temperatures show increase in FWHM and
decrease in asymmetry ratio with respect to its room temperature counterpart.
Experimental Raman scattering data are analyzed successfully using theoretical
Raman line-shape generated by incorporating the temperature dependence of
phonon dispersion relation. Experimental and theoretical temperature dependent
Raman spectra are in good agreement. Although quantum confinement and Fano
effects persists, heating effects start dominating at higher temperatures than
room tempaerature.Comment: 9 Pages, 3 Figures and 1 Tabl
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High fat diet modifies the association of lipoprotein lipase gene polymorphism with high density lipoprotein cholesterol in an Asian Indian population
Background
Single nucleotide polymorphisms (SNPs) in lipoprotein lipase gene (LPL) have been shown to influence metabolism related to lipid phenotypes. Dietary factors have been shown to modify the association between LPL SNPs and lipids; however, to date, there are no studies in South Asians. Hence, we tested for the association of four common LPL SNPs with plasma lipids and examined the interactions between the SNPs and dietary factors on lipids in 1,845 Asian Indians.
Methods
The analysis was performed in 788 Type 2 diabetes cases and 1,057 controls randomly chosen from the cross-sectional Chennai Urban Rural Epidemiological Study. Serum triacylglycerol (TAG), serum total cholesterol, and high-density lipoprotein cholesterol (HDL-C) were measured using a Hitachi-912 autoanalyzer (Roche Diagnostics GmbH, Mannheim, Germany). Dietary intake was assessed using a semi-quantitative food frequency questionnaire. The SNPs (rs1121923, rs328, rs4922115 and rs285) were genotyped by polymerase chain reaction followed by restriction enzyme digestion and 20% of samples were sequenced to validate the genotypes obtained. Statistical Package for Social Sciences for Windows version 22.0 (SPSS, Chicago, IL) was used for statistical analysis.
Results
After correction for multiple testing and adjusting for potential confounders, SNPs rs328 and rs285 showed association with HDL-C (P = 0.0004) and serum TAG (P = 1×10−5), respectively. The interaction between SNP rs1121923 and fat intake (energy %) on HDL-C (P = 0.003) was also significant, where, among those who consumed a high fat diet (28.4 ± 2.5%), the T allele carriers (TT + XT) had significantly higher HDL-C concentrations (P = 0.0002) and 30% reduced risk of low HDL-C levels compared to the CC homozygotes. None of the interactions on other lipid traits were statistically significant.
Conclusion
Our findings suggest that individuals carrying T allele of the SNP rs1121923 have increased HDL-C levels when consuming a high fat diet compared to CC homozygotes. Our finding warrants confirmation in prospective studies and randomized controlled trials
E2F5 status significantly improves malignancy diagnosis of epithelial ovarian cancer
<p>Abstract</p> <p>Background</p> <p>Ovarian epithelial cancer (OEC) usually presents in the later stages of the disease. Factors, especially those associated with cell-cycle genes, affecting the genesis and tumour progression for ovarian cancer are largely unknown. We hypothesized that over-expressed transcription factors (TFs), as well as those that are driving the expression of the OEC over-expressed genes, could be the key for OEC genesis and potentially useful tissue and serum markers for malignancy associated with OEC.</p> <p>Methods</p> <p>Using a combination of computational (selection of candidate TF markers and malignancy prediction) and experimental approaches (tissue microarray and western blotting on patient samples) we identified and evaluated E2F5 transcription factor involved in cell proliferation, as a promising candidate regulatory target in early stage disease. Our hypothesis was supported by our tissue array experiments that showed E2F5 expression only in OEC samples but not in normal and benign tissues, and by significantly positively biased expression in serum samples done using western blotting studies.</p> <p>Results</p> <p>Analysis of clinical cases shows that of the E2F5 status is characteristic for a different population group than one covered by CA125, a conventional OEC biomarker. E2F5 used in different combinations with CA125 for distinguishing malignant cyst from benign cyst shows that the presence of CA125 or E2F5 increases sensitivity of OEC detection to 97.9% (an increase from 87.5% if only CA125 is used) and, more importantly, the presence of both CA125 and E2F5 increases specificity of OEC to 72.5% (an increase from 55% if only CA125 is used). This significantly improved accuracy suggests possibility of an improved diagnostics of OEC. Furthermore, detection of malignancy status in 86 cases (38 benign, 48 early and late OEC) shows that the use of E2F5 status in combination with other clinical characteristics allows for an improved detection of malignant cases with sensitivity, specificity, F-measure and accuracy of 97.92%, 97.37%, 97.92% and 97.67%, respectively.</p> <p>Conclusions</p> <p>Overall, our findings, in addition to opening a realistic possibility for improved OEC diagnosis, provide an indirect evidence that a cell-cycle regulatory protein E2F5 might play a significant role in OEC pathogenesis.</p
A generalised porous medium approach to study thermo-fluid dynamics in human eyes
The present work describes the application of the generalised porous medium model to study heat and fluid flow in healthy and glaucomatous eyes of different subject specimens, considering the presence of ocular cavities and porous tissues. The 2D computational model, implemented into the open-source software OpenFOAM, has been verified against benchmark data for mixed convection in domains partially filled with a porous medium. The verified model has been employed to simulate the thermo-fluid dynamic phenomena occurring in the anterior section of four patient-specific human eyes, considering the presence of anterior chamber (AC), trabecular meshwork (TM), Schlemm’s canal (SC), and collector channels (CC). The computational domains of the eye are extracted from tomographic images. The dependence of TM porosity and permeability on intraocular pressure (IOP) has been analysed in detail, and the differences between healthy and glaucomatous eye conditions have been highlighted, proving that the different physiological conditions of patients have a significant influence on the thermo-fluid dynamic phenomena. The influence of different eye positions (supine and standing) on thermo-fluid dynamic variables has been also investigated: results are presented in terms of velocity, pressure, temperature, friction coefficient and local Nusselt number. The results clearly indicate that porosity and permeability of TM are two important parameters that affect eye pressure distribution
CFD simulation of fluid flow and heat transfer in high frequency pulse tube refrigerators
Genetic variation in exon 5 of troponin - I gene in hypertrophic cardiomyopathy cases
Background: Cardiomyopathies are a heterogeneous group of heart muscle
disorders and are classified as 1) Hypertrophic Cardiomyopathy (HCM) 2)
Dilated cardiomyopathy (DCM) 3) Restrictive cardiomyopathy (RCM) and 4)
Arrhythmogenic right ventricular dysplasia (ARVD) as per WHO
classification, of which HCM and DCM are common. HCM is a complex but
relatively common form of inherited heart muscle disease with
prevalence of 1 in 500 individuals and is commonly associated with
sarcomeric gene mutations. Cardiac muscle troponin I (TNNI-3) is one
such sarcomeric protein and is a subunit of the thin
filament-associated troponin-tropomyosin complex involved in calcium
regulation of skeletal and cardiac muscle contraction. Mutations in
this gene were found to be associated with a history of sudden cardiac
death in HCM patients. Aim: Therefore the present study aims to
identify for mutations associated with troponin I gene in a set of HCM
patients from Indian population. Materials and Methods: Mutational
analyses of 92 HCM cases were carried out following PCR based SSCP
analysis. Results: The study revealed band pattern variation in 3
cases from a group of 92 HCM patients. This band pattern variation, on
sequencing revealed base changes, one at nt 2560 with G>T
transversion in exon-5 region with a wobble and others at nt 2479 and
nt 2478 with G>C and C>G transversions in the intronic region
upstream of the exon 5 on sequencing. Further analysis showed that one
of the probands showed apical form of hypertrophy, two others showing
asymmetric septal hypertrophy. Two of these probands showed family
history of the condition. Conclusions: Hence, the study supports
earlier reports of involvement of TNNI-3 in the causation of apical and
asymmetrical forms of hypertrophy
Effect of parthenin on mitochondrial oxidative phosphorylation
The sesquiterpene lactone, 'parthenin' the toxic principle of the allergenic weed Parthenium hysterophorus, inhibited 'state 3' respiration and stimulated 'state 4' respiration in rat liver and kidney mitochondria as well as ATPase activity in the presence of ions. These properties indicate that the toxic action of parthenin may be related to its interference with oxidative phosphorylation
Nutritional evaluation of silage made from the toxic weed parthenium hysterophorus in animals
After ensilation, the toxic Compositae weed Parthenium hysterophorus was devoid of the toxic principle parthenin. Laboratory-scale ensilation indicated that no parthenin was detectable after 5 wk of anaerobic fermentation. For animal feeding studies, silage was made on a large scale from Parthenium mixed with maize or from Parthenium alone. Crossbred bull and buffalo bull calves were fed diets containing the silages, or control diet without silage, for 12 wk. The animals consumed both silages with relish, and body weight gains of silage-fed calves did not differ from those of the controls. The digestibilities of dry matter, fibre and nitrogen-free extract were greater with the control diet, but the biological value of proteins tended to be greater with the silage-containing diets. Haematological studies indicated no significant differences between experimental and control groups in selected parameters, except for a reduction in blood urea nitrogen in the animals fed silage. The possible causes for these biochemical alterations are discussed. Since the nutritive value of Parthenium silage compares favourably with the standard diet, and Parthenium seeds collected from the silage did not germinate, we suggest that ensilation can be used as an additional method in the containment and eradication of these plants, which grow wild in India
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