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Nessle CN, Ghosal S, Mathews C, Taylor D, Myers J, Raj A, Panigrahi A. Weak correlation of bleeding scores to platelet electron microscopy: A retrospective chart review of pediatric patients with delta-storage pool disorder. Pediatr Blood Cancer 2019; 66:e27505. [PMID: 30345617 DOI: 10.1002/pbc.27505] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/11/2018] [Accepted: 09/24/2018] [Indexed: 11/06/2022]
Abstract
BACKGROUND Delta granule storage pool deficiency (δ-SPD) is a rare platelet disorder in which a deficiency of platelet granules leads to poor aggregation, resulting in varying clinical bleeding phenotypes. Children with δ-SPD have variable laboratory results, making the proper diagnosis and evaluation controversial. OBJECTIVES To describe the demographic and laboratory trends of this population and to assess the value of electron microscopy in diagnostic evaluation and its correlation to bleeding symptoms. METHODS We performed a retrospective review of 109 pediatric patients diagnosed with δ-SPD. We collected demographic information and bleeding scores using a validated bleeding assessment tool. A descriptive and exploratory analysis was performed. RESULTS The majority of patients were female, with an average age at diagnosis of 11.61 years. Females were diagnosed at a significantly older age presenting most often with menorrhagia, while males presented most commonly with epistaxis. The majority showed normal lumiaggregometry, the mean platelet electron microscopy (PEM) value was 2.37, and the mean bleeding score was 6. Bleeding assessment tool and PEM had a significantly weak correlation. CONCLUSIONS Patients with more dense granules per platelet had higher bleeding scores than those with fewer dense granules per platelet. The current body of evidence does not favor the use of PEM in routine clinical practice, and results are difficult to interpret. In patients with severe mucocutaneous bleeding symptoms and normal platelet aggregation studies, consideration should be given to an alternative diagnosis and further evaluation is warranted.
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Hazra S, Jayaprakash KS, Pandian K, Raj A, Mitra SK, Sen AK. Non-inertial lift induced migration for label-free sorting of cells in a co-flowing aqueous two-phase system. Analyst 2019; 144:2574-2583. [DOI: 10.1039/c8an02267d] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We present a novel label-free passive microfluidic technique for isolation of cancer cells (EpCAM+ and CD45−) from peripheral blood mononuclear cells (PBMCs) (CD45+ and EpCAM−) in aqueous two-phase system (ATPS).
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Sharon L, Baliga S, Biranthabail D, Shah J, Shenoy S, Raj A. Fluorescent In Situ Hybridization: A Rapid diagnostic test for the detection and speciation of Mycobacterial infection. Int J Infect Dis 2018. [DOI: 10.1016/j.ijid.2018.04.4207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Raj A, Sen AK. Entry and passage behavior of biological cells in a constricted compliant microchannel. RSC Adv 2018; 8:20884-20893. [PMID: 35542327 PMCID: PMC9080859 DOI: 10.1039/c8ra02763c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/28/2018] [Indexed: 11/30/2022] Open
Abstract
We report an experimental and theoretical investigation of the entry and passage behaviour of biological cells (HeLa and MDA-MB-231) in a constricted compliant microchannel. Entry of a cell into a micro-constriction takes place in three successive regimes: protrusion and contact (cell protrudes its leading edge and makes a contact with the channel wall), squeeze (cell deforms to enter into the constriction) and release (cell starts moving forward). While the protrusion and contact regime is insensitive to the flexibility of the channel, the squeeze zone is significantly smaller in the case of a more compliant channel. Similarly, in the release zone, the acceleration of the cells into the microconstriction is higher in the case of a more compliant channel. The results showed that for a fixed size ratio ρ and E c, the extension ratio λ decreases and transit velocity U c increases with increase in the compliance parameter f p. The variation in the cell velocity is governed by force due to the cell stiffness F s as well as that due to the viscous dampening F d, explained using the Kelvin-Voigt viscoelastic model. The entry time t e = m(ρ) k 1 (1 + f p) k 2 (E c) k 3 and induced hydrodynamic resistance of a cell ΔR c/R = k(ρ) a (1 + k f f p) b (k E E c) c were correlated with cell size ratio ρ, Young's modulus E c and compliance parameter f p, which showed that both entry time t e and the induced hydrodynamic resistance ΔR c are most sensitive to the change in the compliance parameter f p. This study provides understanding of the passage of cells in compliant micro-confinements that can have significant impact on mechanophenotyping of single cells.
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Perego M, Maurer M, Wang JX, Shaffer S, Müller AC, Parapatics K, Li L, Hristova D, Shin S, Keeney F, Liu S, Xu X, Raj A, Jensen JK, Bennett KL, Wagner SN, Somasundaram R, Herlyn M. A slow-cycling subpopulation of melanoma cells with highly invasive properties. Oncogene 2018; 37:302-312. [PMID: 28925403 PMCID: PMC5799768 DOI: 10.1038/onc.2017.341] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/02/2017] [Accepted: 08/12/2017] [Indexed: 12/16/2022]
Abstract
Melanoma is a heterogeneous tumor with different subpopulations showing different proliferation rates. Slow-cycling cells were previously identified in melanoma, but not fully biologically characterized. Using the label-retention method, we identified a subpopulation of slow-cycling cells, defined as label-retaining cells (LRC), with strong invasive properties. We demonstrate through live imaging that LRC are leaving the primary tumor mass at a very early stage and disseminate to peripheral organs. Through global proteome analyses, we identified the secreted protein SerpinE2/protease nexin-1 as causative for the highly invasive potential of LRC in melanomas.
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Raj A, Shah P, Agrawal N. Sedentary behavior and altered metabolic activity by AgNPs ingestion in Drosophila melanogaster. Sci Rep 2017; 7:15617. [PMID: 29142316 PMCID: PMC5688153 DOI: 10.1038/s41598-017-15645-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/30/2017] [Indexed: 11/09/2022] Open
Abstract
Among several nanoparticles, silver nanoparticles (AgNPs) are extensively used in a wide variety of consumer products due to its unique antimicrobial property. However, dosage effect of AgNPs on behavior and metabolic activity in an in vivo condition is not well studied. Therefore, to elucidate the impact of AgNPs on behavior and metabolism, systematic and detailed dosages study of AgNPs was performed by rearing Drosophila melanogaster on food without and with AgNPs. We found that dietary intake of AgNPs at early larval stage leads to behavioral abnormalities such as poor crawling and climbing ability of larvae and adults respectively. Interestingly, intake of higher dosage of AgNPs at larval stage significantly altered metabolic activity that includes lipid, carbohydrate and protein levels in adult flies. Further, detailed analysis revealed that AgNPs causes remarkable reduction in the number of lipid droplets (LDs) which are lipid storage organelles in Drosophila. We also observed an increased production of reactive oxygen species (ROS) in AgNPs ingested larval tissues. These results strongly imply that higher dosage of AgNPs ingestion from early larval stage of Drosophila is inimical and thereby draws concern towards the usage of AgNPs in consumer goods.
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Raj A, Dixit M, Doble M, Sen AK. A combined experimental and theoretical approach towards mechanophenotyping of biological cells using a constricted microchannel. LAB ON A CHIP 2017; 17:3704-3716. [PMID: 28983550 DOI: 10.1039/c7lc00599g] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We report a combined experimental and theoretical technique that enables the characterization of various mechanical properties of biological cells. The cells were infused into a microfluidic device that comprises multiple parallel micro-constrictions to eliminate device clogging and facilitate characterization of cells of different sizes and types on a single device. The extension ratio λ and transit velocity Uc of the cells were measured using high-speed and high-resolution imaging which were then used in a theoretical model to predict the Young's modulus Ec = f(λ, Uc) of the cells. The predicted Young's modulus Ec values for three different cell lines (182 ± 34.74 Pa for MDA MB 231, 360 ± 75 Pa for MCF 10A and, 763 ± 93 Pa for HeLa) compare well with those reported in the literature from micropipette measurements and atomic force microscopy measurement within 10% and 15%, respectively. Also, the Young's modulus of MDA-MB-231 cells treated with 50 μM 4-hyrdroxyacetophenone (for localization of myosin II) for 30 min was found out to be 260 ± 52 Pa. The entry time te of cells into the micro-constrictions was predicted using the model and validated using experimentally measured data. The entry and transit behaviors of cells in the micro-constriction including cell deformation (extension ratio λ) and velocity Uc were experimentally measured and used to predict various cell properties such as the Young's modulus, cytoplasmic viscosity and induced hydrodynamic resistance of different types of cells. The proposed combined experimental and theoretical approach leads to a new paradigm for mechanophenotyping of biological cells.
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Raj A, Wang M, Liu C, Ali L, Karlsson NG, Claesson PM, Dėdinaitė A. Molecular synergy in biolubrication: The role of cartilage oligomeric matrix protein (COMP) in surface-structuring of lubricin. J Colloid Interface Sci 2017; 495:200-206. [DOI: 10.1016/j.jcis.2017.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 02/03/2017] [Accepted: 02/06/2017] [Indexed: 11/28/2022]
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Raj A, Shah P, Agrawal N. Dose-dependent effect of silver nanoparticles (AgNPs) on fertility and survival of Drosophila: An in-vivo study. PLoS One 2017; 12:e0178051. [PMID: 28542630 PMCID: PMC5443555 DOI: 10.1371/journal.pone.0178051] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 05/06/2017] [Indexed: 11/18/2022] Open
Abstract
Silver nanoparticles (AgNPs) containing consumer products have been proliferating in the market due to its unique antimicrobial property, however, lack of in-depth knowledge about their potential effect on human health in a longer run is of great concern. Therefore, we investigated dose-dependent in vivo effect of AgNPs using Drosophila as a model system. Drosophila, a genetically tractable organism with distinct developmental stages, short life cycle and significant homology with human serves as an ideal organism to study nanomaterial-mediated toxicity. Our studies suggest that ingestion of AgNPs in Drosophila during adult stage for short and long duration significantly affects egg laying capability along with impaired growth of ovary. Additionally, dietary intake of AgNPs from larval stage has more deleterious effects that result in reduced survival, longevity, ovary size and egg laying capability at a further lower dosage. Interestingly, the trans-generational effect of AgNPs was also observed without feeding progeny with AgNPs, thereby suggesting its impact from previous generation. Our results strongly imply that higher doses of AgNPs and its administration early during development is detrimental to the reproductive health and survival of Drosophila that follows in generations to come without feeding them to AgNPs.
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Raj A, Wang M, Zander T, Wieland DF, Liu X, An J, Garamus VM, Willumeit-Römer R, Fielden M, Claesson PM, Dėdinaitė A. Lubrication synergy: Mixture of hyaluronan and dipalmitoylphosphatidylcholine (DPPC) vesicles. J Colloid Interface Sci 2017; 488:225-233. [DOI: 10.1016/j.jcis.2016.10.091] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/28/2016] [Accepted: 10/31/2016] [Indexed: 10/20/2022]
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Reed E, Salazar M, Servin AE, Silverman JG, Rusch MLA, Zuniga ML, Raj A. Economic vulnerability and implications for adolescent pregnancy among girls at the US–Mexico border. Contraception 2016. [DOI: 10.1016/j.contraception.2016.07.144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Salazar M, West B, Raj A, Torreblanca M, Reed E. Contraceptive use and risk perceptions for STI and unintended pregnancy
among adolescent females in San Diego County at the US-Mexico Border. Ann Glob Health 2016. [DOI: 10.1016/j.aogh.2016.04.206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Zander T, Wieland DF, Raj A, Wang M, Nowak B, Krywka C, Dėdinaitė A, Claesson PM, Garamus VM, Schreyer A, Willumeit-Römer R. The influence of hyaluronan on the structure of a DPPC—bilayer under high pressures. Colloids Surf B Biointerfaces 2016; 142:230-238. [DOI: 10.1016/j.colsurfb.2016.02.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 02/05/2023]
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Wieland DCF, Degen P, Zander T, Gayer S, Raj A, An J, Dėdinaitė A, Claesson P, Willumeit-Römer R. Structure of DPPC-hyaluronan interfacial layers - effects of molecular weight and ion composition. SOFT MATTER 2016; 12:729-740. [PMID: 26508354 DOI: 10.1039/c5sm01708d] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Hyaluronan and phospholipids play an important role in lubrication in articular joints and provide in combination with glycoproteins exceptionally low friction coefficients. We have investigated the structural organization of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) Langmuir layers at the solution-air interface at different length scales with respect to the adsorption of hyaluronan (HA). This allows us to assemble a comprehensive picture of the adsorption and the resulting structures, and how they are affected by the molecular weight of HA and the presence of calcium ions. Brewster angle microscopy and grazing incident diffraction were used to determine the lateral structure at the micro- and macro scale. The data reveals an influence of HA on both the macro and micro structure of the DPPC Langmuir layer, and that the strength of this effect increases with decreasing molecular weight of HA and in presence of calcium ions. Furthermore, from X-ray reflectivity measurements we conclude that HA adsorbs to the hydrophilic part of DPPC, but data also suggest that two types of interfacial structures are formed at the interface. We argue that hydrophobic forces and electrostatic interactions play important rules for the association between DPPC and HA. Surface pressure area isotherms were used to determine the influence of HA on the phase behavior of DPPC while electrophoretic mobility measurements were used to gain insight into the binding of calcium ions to DPPC vesicles and hyaluronan.
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Sajeesh P, Raj A, Doble M, Sen AK. Characterization and sorting of cells based on stiffness contrast in a microfluidic channel. RSC Adv 2016. [DOI: 10.1039/c6ra09099k] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
This paper reports the characterization and sorting of cells based on stiffness contrast. A microfluidic device with focusing and spacing control for stiffness based sorting of cells is designed, fabricated and demonstrated.
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Singh MP, Chandran C, Sarwa A, Kumar A, Gupta M, Raj A, Ratho RK. Outbreak of chickenpox in a Union Territory of North India. Indian J Med Microbiol 2015; 33:524-7. [DOI: 10.4103/0255-0857.167335] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Gautam V, Mewara A, Raj A, Gupta V, Singla N, Ray P. High prevalence of New Delhi metallo-β-lactamase in Acinetobacter calcoaceticus-A. baumannii complex at two tertiary care centres in north India. Indian J Med Microbiol 2015; 32:455-6. [PMID: 25297039 DOI: 10.4103/0255-0857.142231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Painkra VK, Jhariya MK, Raj A. Assessment of knowledge of medicinal plants and their use in tribal region of Jashpur district of Chhattisgarh, India. ACTA ACUST UNITED AC 2015. [DOI: 10.31018/jans.v7i1.628] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The present study was conducted to assess the knowledge of medicinal plants and their use in tribal region of Jashpur district of Chhattisgarh. Under the socio-economic profile, farmers of middle age (36-55 yrs) people showed the maximum percentage (78%) distribution and frequency, 50 per cent of respondents belonged to primary to middle school level of education and 63 per cent of respondents were having medium size of family (5 to 8 members). A total number of 50 medicinal plant species belonging to 29 families were recorded, in which Euphorbiaceae registered as the largest family with 4 plant species (8%). Shrub showed their maximum presence (34%) followed by tree (32%), herb (20%) and climber (14%). As per knowledge of respondents about medicinal plants Haldi and Bhui-neem is mostly use as medicinal purpose as 5.2% (n=40) followed by Harra, Munga, Karanj and Hadjod (3.9% each). This information through respondent (tribals) showed very diverse nature of medicinal flora, their usage in healing purpose with socioeconomic/ living standard upliftment. Therefore, it is needful aspect of conserving these biological resources for sustainable ecosystem.
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Wang M, Zander T, Liu X, Liu C, Raj A, Florian Wieland D, Garamus VM, Willumeit-Römer R, Claesson PM, Dėdinaitė A. The effect of temperature on supported dipalmitoylphosphatidylcholine (DPPC) bilayers: Structure and lubrication performance. J Colloid Interface Sci 2015; 445:84-92. [DOI: 10.1016/j.jcis.2014.12.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/09/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
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Dasgupta A, Saggurti N, Donta B, Battala M, Ghule M, Nair S, Ritter J, Silverman J, Raj A. Intimate partner violence and condom versus other modern contraception
use among married women in rural India. Ann Glob Health 2015. [DOI: 10.1016/j.aogh.2015.02.1001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Kuceyeski AF, Vargas W, Dayan M, Monohan E, Blackwell C, Raj A, Fujimoto K, Gauthier SA. Modeling the relationship among gray matter atrophy, abnormalities in connecting white matter, and cognitive performance in early multiple sclerosis. AJNR Am J Neuroradiol 2014; 36:702-9. [PMID: 25414004 DOI: 10.3174/ajnr.a4165] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/02/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Quantitative assessment of clinical and pathologic consequences of white matter abnormalities in multiple sclerosis is critical in understanding the pathways of disease. This study aimed to test whether gray matter atrophy was related to abnormalities in connecting white matter and to identify patterns of imaging biomarker abnormalities that were related to patient processing speed. MATERIALS AND METHODS Image data and Symbol Digit Modalities Test scores were collected from a cohort of patients with early multiple sclerosis. The Network Modification Tool was used to estimate connectivity irregularities by projecting white matter abnormalities onto connecting gray matter regions. Partial least-squares regression quantified the relationship between imaging biomarkers and processing speed as measured by the Symbol Digit Modalities Test. RESULTS Atrophy in deep gray matter structures of the thalami and putamen had moderate and significant correlations with abnormalities in connecting white matter (r = 0.39-0.41, P < .05 corrected). The 2 models of processing speed, 1 for each of the WM imaging biomarkers, had goodness-of-fit (R(2)) values of 0.42 and 0.30. A measure of the impact of white matter lesions on the connectivity of occipital and parietal areas had significant nonzero regression coefficients. CONCLUSIONS We concluded that deep gray matter regions may be susceptible to inflammation and/or demyelination in white matter, possibly having a higher sensitivity to remote degeneration, and that lesions affecting visual processing pathways were related to processing speed. The Network Modification Tool may be used to quantify the impact of early white matter abnormalities on both connecting gray matter structures and processing speed.
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Arumugham R, Raj A, Nagarajan M, Vijilakshmi R. Survival Analysis of Breast Cancer Patients Treated at a Tertiary Care Centre in Southern India. Ann Oncol 2014. [DOI: 10.1093/annonc/mdu327.72] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Kiriazova T, Cheng DM, Coleman SM, Blokhina E, Krupitsky E, Lira MC, Bridden C, Raj A, Samet JH. Factors associated with study attrition among HIV-infected risky drinkers in St. Petersburg, Russia. HIV CLINICAL TRIALS 2014; 15:116-25. [PMID: 24947535 DOI: 10.1310/hct1503-116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Participant attrition in HIV longitudinal studies may introduce bias and diminish research quality. The identification of participant characteristics that are predictive of attrition might inform retention strategies. OBJECTIVE The study aimed to identify factors associated with attrition among HIV-infected Russian risky drinkers from the secondary HIV prevention HERMITAGE trial. We examined whether current injection drug use (IDU), binge drinking, depressive symptoms, HIV status nondisclosure, stigma, and lifetime history of incarceration were predictors of study attrition. We also explored effect modification due to gender. METHODS Complete loss to follow-up (LTFU), defined as no follow-up visits after baseline, was the primary outcome, and time to first missed visit was the secondary outcome. We used multiple logistic regression models for the primary analysis, and Cox proportional hazards models for the secondary analysis. RESULTS Of 660 participants, 101 (15.3%) did not return after baseline. No significant associations between independent variables and complete LTFU were observed. Current IDU and HIV status nondisclosure were significantly associated with time to first missed visit (adjusted hazard ratio [AHR], 1.39; 95% CI, 1.03-1.87; AHR, 1.38; 95% CI, 1.03-1.86, respectively). Gender stratified analyses suggested a larger impact of binge drinking among men and history of incarceration among women with time to first missed visit. CONCLUSIONS Although no factors were significantly associated with complete LTFU, current IDU and HIV status nondisclosure were significantly associated with time to first missed visit in HIV-infected Russian risky drinkers. An understanding of these predictors may inform retention efforts in longitudinal studies.
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Glodzik L, Kuceyeski A, Rusinek H, Tsui W, Mosconi L, Li Y, Osorio RS, Williams S, Randall C, Spector N, McHugh P, Murray J, Pirraglia E, Vallabhajosula S, Raj A, de Leon MJ. Reduced glucose uptake and Aβ in brain regions with hyperintensities in connected white matter. Neuroimage 2014; 100:684-691. [PMID: 24999038 DOI: 10.1016/j.neuroimage.2014.06.060] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 06/02/2014] [Accepted: 06/18/2014] [Indexed: 11/24/2022] Open
Abstract
Interstitial concentration of amyloid beta (Aß) is positively related to synaptic activity in animal experiments. In humans, Aß deposition in Alzheimer's disease overlaps with cortical regions highly active earlier in life. White matter lesions (WML) disrupt connections between gray matter (GM) regions which in turn changes their activation patterns. Here, we tested if WML are related to Aß accumulation (measured with PiB-PET) and glucose uptake (measured with FDG-PET) in connected GM. WML masks from 72 cognitively normal (age 61.7 ± 9.6 years, 71% women) individuals were obtained from T2-FLAIR. MRI and PET images were normalized into common space, segmented and parcellated into gray matter (GM) regions. The effects of WML on connected GM regions were assessed using the Change in Connectivity (ChaCo) score. Defined for each GM region, ChaCo is the percentage of WM tracts connecting to that region that pass through the WML mask. The regional relationship between ChaCo, glucose uptake and Aß was explored via linear regression. Subcortical regions of the bilateral caudate, putamen, calcarine, insula, thalamus and anterior cingulum had WM connections with the most lesions, followed by frontal, occipital, temporal, parietal and cerebellar regions. Regional analysis revealed that GM with more lesions in connecting WM and thus impaired connectivity had lower FDG-PET (r = 0.20, p<0.05 corrected) and lower PiB uptake (r = 0.28, p<0.05 corrected). Regional regression also revealed that both ChaCo (β = 0.045) and FDG-PET (β = 0.089) were significant predictors of PiB. In conclusion, brain regions with more lesions in connecting WM had lower glucose metabolism and lower Aß deposition.
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Weis B, Schmidt J, Maamar H, Raj A, Lin H, Tóth C, Riedmann K, Raddatz G, Seitz HK, Ho AD, Lyko F, Linhart HG. Inhibition of intestinal tumor formation by deletion of the DNA methyltransferase 3a. Oncogene 2014; 34:1822-30. [PMID: 24837369 DOI: 10.1038/onc.2014.114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 03/13/2014] [Accepted: 03/26/2014] [Indexed: 12/31/2022]
Abstract
Aberrant de novo methylation of DNA is considered an important mediator of tumorigenesis. To investigate the role of de novo DNA methyltransferase 3a (Dnmt3a) in intestinal tumor development, we analyzed the expression of Dnmt3a in murine colon crypts, murine colon adenomas and human colorectal cancer using RNA fluorescence in situ hybridization (FISH), quantitative PCR and immunostaining. Following conditional deletion of Dnmt3a in the colon of APC((Min/+)) mice, we analyzed tumor numbers, genotype of macroadenomas and laser dissected microadenomas, global and regional DNA methylation and gene expression. Our results showed increased Dnmt3a expression in colon adenomas of APC((Min/+)) mice and human colorectal cancer samples when compared with control tissue. Interestingly, in tumor tissue, RNA FISH analysis showed highest Dnmt3a expression in Lgr5-positive stem/progenitor cells. Deletion of Dnmt3a in APC((Min/+)) mice reduced colon tumor numbers by ~40%. Remaining adenomas and microadenomas almost exclusively contained the non-recombined Dnmt3a allele; no tumors composed of the inactivated Dnmt3a allele were detected. DNA methylation was reduced at the Oct4, Nanog, Tff2 and Cdkn1c promoters and expression of the tumor-suppressor genes Tff2 and Cdkn1c was increased. In conclusion, our results show that Dnmt3a is predominantly expressed in the stem/progenitor cell compartment of tumors and that deletion of Dnmt3a inhibits the earliest stages of intestinal tumor development.
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