1,602 research outputs found

    Fluorescent In-Situ Hybridization is the Hand Mirror of Cytogenetics: A Rare Case of Near Tetraploidy in Pediatric Acute Lymphoblastic Leukemia

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    Identification of specific chromosomal changes has important prognostic and biological implications in childhood Acute Lymphoblastic Leukemia (ALL). ALL cases with 90 chromosomes are rare. Here, we report a case of near-tetraploidy in a 4 year old boy diagnosed with B-cell ALL, where the ploidy was identified by Fluorescent In- Situ Hybridization (FISH) and confirmed by Conventional Cytogenetics. Our aim was to enumerate multiple signals observed by FISH, and to confirm the same by cytogenetics. FISH on cytogenetically fixed air-dried slides was performed by using BCR/ABL and MLL probe .Two hundred cells were scored. BMA was cultured and G-banded metaphases were analyzed in accordance with ISCN 2013. The results of the FISH test showed more than two signals and cytogenetics revealed clones of near-tetraploidy with mn 90, karyotype: 90-92, 4nXXY,-Y,-10,-10,-13, +14, +17, along with normal clones. The tetraploidy condition compared to hyperdiploid ALL has a poorer prognosis and the rarity of these cases makes accounting on treatment decisions a supposition. Presently, the patient is on standard treatment for ALL (UK ALL regime A). The numerical abnormality detected by FISH was confirmed by cytogenetics, which facilitated in reporting the results of this case earlier than the defined turnaround time. Therefore author opines that FISH reports should also contain observed additional information along with positive or negative status of the requested test

    Shaping bursting by electrical coupling and noise

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    Gap-junctional coupling is an important way of communication between neurons and other excitable cells. Strong electrical coupling synchronizes activity across cell ensembles. Surprisingly, in the presence of noise synchronous oscillations generated by an electrically coupled network may differ qualitatively from the oscillations produced by uncoupled individual cells forming the network. A prominent example of such behavior is the synchronized bursting in islets of Langerhans formed by pancreatic \beta-cells, which in isolation are known to exhibit irregular spiking. At the heart of this intriguing phenomenon lies denoising, a remarkable ability of electrical coupling to diminish the effects of noise acting on individual cells. In this paper, we derive quantitative estimates characterizing denoising in electrically coupled networks of conductance-based models of square wave bursting cells. Our analysis reveals the interplay of the intrinsic properties of the individual cells and network topology and their respective contributions to this important effect. In particular, we show that networks on graphs with large algebraic connectivity or small total effective resistance are better equipped for implementing denoising. As a by-product of the analysis of denoising, we analytically estimate the rate with which trajectories converge to the synchronization subspace and the stability of the latter to random perturbations. These estimates reveal the role of the network topology in synchronization. The analysis is complemented by numerical simulations of electrically coupled conductance-based networks. Taken together, these results explain the mechanisms underlying synchronization and denoising in an important class of biological models

    Empirical validation of statistical parametric mapping for group imaging of fast neural activity using electrical impedance tomography

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    Electrical impedance tomography (EIT) allows for the reconstruction of internal conductivity from surface measurements. A change in conductivity occurs as ion channels open during neural activity, making EIT a potential tool for functional brain imaging. EIT images can have  >10 000 voxels, which means statistical analysis of such images presents a substantial multiple testing problem. One way to optimally correct for these issues and still maintain the flexibility of complicated experimental designs is to use random field theory. This parametric method estimates the distribution of peaks one would expect by chance in a smooth random field of a given size. Random field theory has been used in several other neuroimaging techniques but never validated for EIT images of fast neural activity, such validation can be achieved using non-parametric techniques. Both parametric and non-parametric techniques were used to analyze a set of 22 images collected from 8 rats. Significant group activations were detected using both techniques (corrected p  <  0.05). Both parametric and non-parametric analyses yielded similar results, although the latter was less conservative. These results demonstrate the first statistical analysis of such an image set and indicate that such an analysis is an approach for EIT images of neural activity

    Suitable thicknesses of base metal and interlayer, and evolution of phases for Ag/Sn/Ag transient liquid-phase joints used for power die attachment

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    Both real Si insulated gate bipolar transistors (IGBT) with conventional Ni\Ag metallization and a dummy Si die with thickened Ni\Ag metallization have been bonded on Ag foils electroplated with 2.7 m and 6.8 m thick Sn as an interlayer at 250ºC for 0 min, 40 min and 640 min. From microstructure characterization of the resulting joints, suitable thicknesses are suggested for the Ag base metal and the Sn interlayer for Ag/Sn/Ag transient liquid phase (TLP) joints used in power die attachment, and the diffusivities of Ag and Sn in the Ag phase are extracted. In combination with the kinetic constants of Ag3Sn growth and diffusivities of Ag and Sn in Ag reported in the literature, the extracted diffusivities of Ag and Sn in Ag phase are also used to simulate and predict the diffusion-controlled growth and evolution of phases in the Ag/Sn/Ag TLP joints during an extended bonding process and in service

    Visceral Leishmaniasis in Muzaffarpur District, Bihar, India from 1990 to 2008

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    BACKGROUND: Visceral Leishmaniasis (VL) is a vector-borne disease transmitted by Phlebotomus argentipes. To understand the VL seasonality, annual and monthly variations of VL incidence and its relationship to meteorological variables, the numbers of VL cases reported in Muzaffarpur district, Bihar, India from 1990 to 2008 were studied. METHODS: Annual VL incidence per 10,000 and the total number of annual VL cases reported at block Community Health Centres (CHC), Public Hospitals or Non-Governmental Organisations (NGO) and the number of VL cases per month from 2000 to 2008 as well as the monthly average of cases for 2000-08, 2000-04 and 2005-08 periods along with the monthly averages of temperature, rainfall and relative humidity were plotted. VL Standardised Incidence Ratios per block were computed for the periods of 1990-1993, 1994-1998, 1999-2004 and 2005-2008 and month wise from 2002 to 2008. A negative binomial regression model was used to evaluate the association between meteorological variables and the number of VL cases per month from 2000 to 2008. RESULTS: A total of 68,358 VL cases were reported in Muzaffarpur district from 1990 to 2008, ranging from 1,2481 in 1992 to 1,161 in 2001. The blocks with the highest number of cases shifted from East (1990-98) to West (1999-2008). Monthly averages of cases ranged from 149 to 309, highest peak in March-April and another one in July. Monthly VL incidence was associated positively to rainfall and negatively to relative humidity and the numbers of VL cases in the previous month. INTERPRETATION: The number of cases reported to the public health sector allowed the describing of the spatial distribution and temporal variations in the Muzaffarpur from 1990 to 2008. However, to assess the actual VL burden, as well as the efficacy of the control measures applied in the district, reporting from private practices and NGOs should be encouraged

    No association of TNFRSF1B variants with type 2 diabetes in Indians of Indo-European origin

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    <p>Abstract</p> <p>Background</p> <p>There has been no systematic evaluation of the association between genetic variants of type 2 receptor for TNFα (TNFR2) and type 2 diabetes, despite strong biological evidence for the role of this receptor in the pathogenesis of this complex disorder. In view of this, we performed a comprehensive association analysis of <it>TNFRSF1B </it>variants with type 2 diabetes in 4,200 Indo-European subjects from North India.</p> <p>Methods</p> <p>The initial phase evaluated association of seven SNPs viz. rs652625, rs496888, rs6697733, rs945439, rs235249, rs17883432 and rs17884213 with type 2 diabetes in 2,115 participants (1,073 type 2 diabetes patients and 1,042 control subjects). Further, we conducted replication analysis of three associated SNPs in 2,085 subjects (1,047 type 2 diabetes patients and 1,038 control subjects).</p> <p>Results</p> <p>We observed nominal association of rs945439, rs235249 and rs17884213 with type 2 diabetes (<it>P </it>< 0.05) in the initial phase. Haplotype CC of rs945439 and rs235249 conferred increased susceptibility for type 2 diabetes [OR = 1.19 (95%CI 1.03-1.37), <it>P </it>= 0.019/<it>P</it><sub>perm </sub>= 0.076] whereas, TG haplotype of rs235249 and rs17884213 provided protection against type 2 diabetes [OR = 0.83 (95%CI 0.72-0.95, <it>P </it>= 7.2 × 10<sup>-3</sup>/<it>P</it><sub>perm </sub>= 0.019]. We also observed suggestive association of rs496888 with plasma hsCRP levels [<it>P </it>= 0.042]. However, the association of rs945439, rs235249 and rs17884213 with type 2 diabetes was not replicated in the second study population. Meta-analysis of the two studies also failed to detect any association with type 2 diabetes.</p> <p>Conclusions</p> <p>Our two-stage association analysis suggests that <it>TNFRSF1B </it>variants are not the determinants of genetic risk of type 2 diabetes in North Indians.</p

    Intraoperative device closure of atrial septal defects in the Older Population

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    <p>Abstract</p> <p>Objective</p> <p>This study sought to prove the safety and feasibility of intraoperative device closure of atrial septal defect (ASD) with transthoracic minimal invasion in the older patients.</p> <p>Methods</p> <p>From January 2006 to December 2009, 47 patients aged 50 years or more and suffered from atrial septal defect were enrolled in our institution. Patients were divided into two groups, 27 of which in group I with intraoperative device closure and the other 20 in group II with surgical closure. In group I, the method involved a minimal intercostal incision, which was performed after full evaluation of the atrial septal defect by transthoracic echocardiography, and the insertion of the device through the delivery sheath to occlude the atrial septal defect.</p> <p>Results</p> <p>In group I, implantation was ultimately successful in all patients. The complete closure rate at 24 hours and 1 year were 81.5% and 100% respectively. In 6 of 27 patients, minor complications occurred: transient arrhythmia (n = 5) and blood transfusion (n = 3). In group II, all patients were closured successfully; almost all of them needed blood transfusion and suffered from various minor complications though. During a follow-up period of 1 to 5 years, no residual shunt, noticeable mitral regurgitation, significant arrhythmias, thrombosis, or device failure were found. In our comparative studies, group II had significantly longer ICU stay and hospital stay than group I (p < 0.05). The cost of group I was less than that of group II(p < 0.05).</p> <p>Conclusions</p> <p>Minimally invasive transthoracic device closure of the atrial septal defect at advanced age with a domestically made device without cardiopulmonary bypass is safe and feasible under transthoracic echocardiographic guidance. It was cost-savings, yielding better cosmetic results and leaving fewer traumas than surgical closure. Early and mid-term results are encouraging. However, it is necessary to evaluate the long-term results.</p

    Novel role of cPLA2α in membrane and actin dynamics

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    Actin-directed processes such as membrane ruffling and cell migration are regulated by specific signal transduction pathways that become activated by growth factor receptors. The same signaling pathways that lead to modifications in actin dynamics also activate cPLA2α. Moreover, arachidonic acid, the product of cPLA2α activity, is involved in regulation of actin dynamics. Therefore, it was investigated whether cPLA2α plays a role in actin dynamics, more specifically during growth factor-induced membrane ruffling and cell migration. Upon stimulation of ruffling and cell migration by growth factors, endogenous cPLA2α and its active phosphorylated form were shown to relocate at protrusions of the cell membrane involved in actin and membrane dynamics. Inhibition of cPLA2α activity with specific inhibitors blocked growth factor-induced membrane and actin dynamics, suggesting an important role for cPLA2α in these processes

    Accreting Millisecond X-Ray Pulsars

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    Accreting Millisecond X-Ray Pulsars (AMXPs) are astrophysical laboratories without parallel in the study of extreme physics. In this chapter we review the past fifteen years of discoveries in the field. We summarize the observations of the fifteen known AMXPs, with a particular emphasis on the multi-wavelength observations that have been carried out since the discovery of the first AMXP in 1998. We review accretion torque theory, the pulse formation process, and how AMXP observations have changed our view on the interaction of plasma and magnetic fields in strong gravity. We also explain how the AMXPs have deepened our understanding of the thermonuclear burst process, in particular the phenomenon of burst oscillations. We conclude with a discussion of the open problems that remain to be addressed in the future.Comment: Review to appear in "Timing neutron stars: pulsations, oscillations and explosions", T. Belloni, M. Mendez, C.M. Zhang Eds., ASSL, Springer; [revision with literature updated, several typos removed, 1 new AMXP added

    Theory of disk accretion onto supermassive black holes

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    Accretion onto supermassive black holes produces both the dramatic phenomena associated with active galactic nuclei and the underwhelming displays seen in the Galactic Center and most other nearby galaxies. I review selected aspects of the current theoretical understanding of black hole accretion, emphasizing the role of magnetohydrodynamic turbulence and gravitational instabilities in driving the actual accretion and the importance of the efficacy of cooling in determining the structure and observational appearance of the accretion flow. Ongoing investigations into the dynamics of the plunging region, the origin of variability in the accretion process, and the evolution of warped, twisted, or eccentric disks are summarized.Comment: Mostly introductory review, to appear in "Supermassive black holes in the distant Universe", ed. A.J. Barger, Kluwer Academic Publishers, in pres
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