A linear ablating system in the left and right atrium: feasibility, catheter performance and clinical results

IntroductionWe describe the use of a ablating system to compartmentalise and regionally isolate the atria in paroxysmal and persistent atrial fibrillation (AF).Methods40 patients were studied, 25 paroxysmal AF and 14 persistent AF. One patient enrolled was later found to be in left atrial flutter and was excluded. The Cardima Revelation® TX catheter system with Intellitemp® Radiofrequency (RF) energy control device and a Medtronic Atakar® RF generator were used to place wide area circumferential ablations to achieve conduction block into the left and right sided pulmonary veins. Roof lines and mitral isthmus lines were also performed. In patients with persistent AF and in repeat procedures, right atrial compartmentalisation was performed with an anterior superior vena cava (SVC) to inferior vena cava (IVC) line and a septal SVC to IVC line.ResultsAt 6 months, 18 of the 39 patients were asymptomatic, 10 had improved symptoms and 22 were in sinus rhythm. In the paroxysmal group, 11 were asymptomatic, 7 had improved symptoms and 16 (64%) were in sinus rhythm. In the persistent group, 7 were asymptomatic, 3 had improved symptoms and 6 (43%) were in sinus rhythm. The total group AF burden was 37.8 ± 5.4 hrs pre-procedure and 23.1 ± 5.1 hrs at 6 months post procedure. Mean temperature, impedance and power recorded at each pole demonstrated effective power delivery at all poles. No catheter charring was observed, complication rates were comparable to standard AF ablation technique.ConclusionLinear ablation in the left and right atria to mimic Cox’s Maze is feasible and safe using this ablating system.     

Syk associates with clathrin and mediates phosphatidylinositol 3-kinase activation during human rhinovirus internalization

Human rhinovirus (HRV) causes the common cold. The most common acute infection in humans, HRV is a leading cause of exacerbations of asthma and chronic obstruction pulmonary disease because of its ability to exacerbate airway inflammation by altering epithelial cell biology upon binding to its receptor, ICAM-1. ICAM-1 regulates not only viral entry and replication but also signaling pathways that lead to inflammatory mediator production. We recently demonstrated the Syk tyrosine kinase to be an important mediator of HRV-ICAM-1 signaling: Syk regulates replication-independent p38 MAPK activation and IL-8 expression. In leukocytes, Syk regulates receptor-mediated internalization via PI3K. Although PI3K has been shown to regulate HRV-induced IL-8 expression and clathrin-mediated endocytosis of HRV, the role of airway epithelial Syk in this signaling pathway is not known. We postulated that Syk regulates PI3K activation and HRV endocytosis in the airway epithelium. Using confocal microscopy and immunoprecipitation, we demonstrated recruitment of the normally cytosolic Syk to the plasma membrane upon HRV16-ICAM-1 binding, along with Syk-clathrin coassociation. Subsequent incubation at 37 degrees C to permit internalization revealed redistribution of Syk to punctate structures resembling endosomes and colocalization with HRV16. Internalized HRV was not detected in cells overexpressing the kinase inactive Syk(K396R) mutant, indicating that kinase activity was necessary for endocytosis. HRV-induced PI3K activation was dependent on Syk; Syk knockdown by small interfering RNA significantly decreased phosphorylation of the PI3K substrate Akt. Together, these data reveal Syk to be an important mediator of HRV endocytosis and HRV-induced PI3K activation.     

Inhibition of myoblast differentiation by Sfrp1 and Sfrp2

Secreted Frizzled-related proteins (Sfrps) are extracellular regulators of Wnt signalling and play important roles in developmental and oncogenic processes. They are known to be upregulated in regenerating muscle and in myoblast cultures but their function is unknown. Here, we show that the addition of recombinant Sfrp1 or Sfrp2 to C2C12 cell line cultures or to primary cultures of satellite cells results in the inhibition of myotube formation with no significant effect on the cell cycle or apoptosis. Even though at confluence, treated and untreated cultures are identical in appearance, analyses have shown that, for maximum effect, the cells have to be treated while they are proliferating. Furthermore, removal of Sfrp from the culture medium during differentiation restores normal myotube formation. We conclude that Sfrp1 and Sfrp2 act to prevent myoblasts from entering the terminal differentiation process. S. Descamps and J. Levin contributed equally to this work.     

Photosynthetic Rate, Growth, and Yield of Mustard Plants Sprayed with 28-Homobrassinolide

Thirty-day-old plants of mustard (Brassica juncea L.) were sprayed with 10⁻¹⁰, 10⁻⁸, or 10⁻⁶ M aqueous solution of 28-homobrassinolide (HBR). The HBR-treated plants were healthier than those treated with water and yielded more. Maximum increase over control was found in 60-d-old, 10⁻⁸ M-HBR-treated plants in fresh and dry mass per plant, carbonic anhydrase (CA, E.C. 4.2.1.1) activity, and net photosynthetic rate (P _N), at harvest in number of pods per plant and seed yield per plant (the respective values were 25, 30, 34, 69, 24, and 29 %). A further increase in the concentration of HBR (10⁻⁶ M) did not make any additional impact on the growth and yield. Increased CA activity and P _N were correlated with growth and seed yield. This revised version was published online in August 2006 with corrections to the Cover Date.     

Nanovaccine: A novel approach in immunization

Despite great advances in the field of vaccination, there are still needs for novel and effective vaccines because still no effective vaccines have been produced for some diseases such as malaria, acquired immune deficiency syndrome (AIDS), and tuberculosis. Furthermore, many of the existing vaccines have disadvantages such as failure to stimulate completely the immune system, in vivo instability, high toxicity, the need for cold chain, and multiple administrations. Nanotechnology has been raised as a powerful tool for solving these problems in this regard. Generally, nanovaccines are a new generation of vaccines using nanoparticles (NPs) as carriers and/or adjuvants. Due to the similar scale (size) between the NPs and pathogens, the immune system can be stimulated well, resulting in triggered cellular and humoral immunity responses. Other benefits of the nanovaccines include their better stability in blood flow to increase the shelf life in blood, enhanced immune system stimulation, no need for booster doses, no need to maintain the cold chain, and ability to create active targeting. In addition, nanovaccines have raised the hope to treat diseases such as rheumatoid arthritis, AIDS, malaria, and chronic autoimmune, and so forth.     

On Computations for Thermal Radiation in MHD Channel Flow with Heat and Mass Transfer

This study examines the simultaneous effects of heat and mass transfer on the three-dimensional boundary layer flow of viscous fluid between two infinite parallel plates. Magnetohydrodynamic (MHD) and thermal radiation effects are present. The governing problems are first modeled and then solved by homotopy analysis method (HAM). Influence of several embedded parameters on the velocity, concentration and temperature fields are described.     

Thienopyrimidine-based P2Y12 platelet aggregation inhibitors

Herein we describe the design and synthesis of a novel series of potent thienopyrimidine P2Y₁₂ inhibitors and the negative impact protein binding has on the inhibition of platelet aggregation.     

Host stage preference and parasitism behaviour of Aenasius bambawalei an encyrtid parasitoid of Phenacoccus solenopsis

In Pakistan, the cotton mealybug, Phenacoccus solenopsis Tinsley (Sternorrhyncha (Homoptera): Pseudococcidae), is a serious pest of many cultivated plants. A parasitoid, Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae), is associated with P. solenopsis. In order to mass rear A. bambawalei for a biological control programme, it is important to investigate the parasitoid’s host stage preference and its parasitism behaviour for P. solenopsis in order to optimise production. The present study showed that under both choice and no-choice conditions, the parasitoid preferred third instar and pre-reproductive host stage mealybugs for parasitism. Parasitoid larva developing inside the host exhibited a greater longevity, shorter developmental period and longer body size in these preferred host stages. Our study also confirmed that A. bambawalei showed no attraction to male mealybugs and no host feeding on any host stage was recorded. The ability of the parasitoid to effectively discriminate between suitable and non-suitable stages means that it is feasible to rear it on a mixed population.