671 research outputs found
Detecting DNA methylation for cancer diagnostics and prognostics
No full textDNA methylation is an epigenetic process that has roles in many normal cellular processes and dysregulation of which can result in diseases such as cancer. The most well studied form of mammalian DNA methylation is the addition of a methyl group to the number 5 carbon of cytosine in CpG dinucleotides. Gene regulatory elements, such as gene promoters and enhancers associated with dense CpGs, are sensitive to DNA methylation silencing. Multiple studies have shown that promoter methylation profiling of cancer genes may be useful as biomarkers of cancer. DNA methylation information has the potential to provide information on a patient's cancer subtype, treatment response and prognosis. Current DNA methylation detection techniques can be broadly grouped into sodium bisulfite, restriction enzyme and methylated DNA enrichment based techniques. However, techniques for detection DNA methylation have largely been tailored to research purposes and may not be well suited for routine clinical use. In this chapter, some of these common DNA methylation detection methods are reviewed for their suitability in diagnostics. Also discussed are ways how some of these techniques may be or have been adapted for clinical and point-of-care applications. Emerging techniques that have evolved from classical research methods are also introduced
Circulating tumor DNA and liquid biopsy: opportunities, challenges, and recent advances in detection technologies.
No full textCell-free DNA (cfDNA) refers to short fragments of acellular nucleic acids detectable in almost all body fluids, including blood, and is involved in various physiological and pathological phenomena such as immunity, coagulation, aging, and cancer. In cancer patients, a fraction of hematogenous cfDNA originates from tumors, termed circulating tumor DNA (ctDNA), and may carry the same mutations and genetic alterations as those of a primary tumor. Thus, ctDNA potentially provides an opportunity for noninvasive assessment of cancer. Recent advances in ctDNA analysis methods will potentially lead to the development of a liquid biopsy tool for the diagnosis, prognosis, therapy response monitoring, and tracking the rise of new mutant sub-clones in cancer patients. Over the past few decades, cancer-specific mutations in ctDNA have been detected using a variety of untargeted methods such as digital karyotyping, personalized analysis of rearranged ends (PARE), whole-genome sequencing of ctDNA, and targeted approaches such as conventional and digital PCR-based methods and deep sequencing-based technologies. More recently, several chip-based electrochemical sensors have been developed for the analysis of ctDNA in patient samples. This paper aims to comprehensively review the diagnostic, prognostic, and predictive potential of ctDNA as a minimally invasive liquid biopsy for cancer patients. We also present an overview of current advances in the analytical sensitivity and accuracy of ctDNA analysis methods as well as biological and technical challenges, which need to be resolved for the integration of ctDNA analysis into routine clinical practice
An amplification-free electrochemical detection of exosomal miRNA-21 in serum samples
No full textRecent evidence suggests that small non-coding RNAs or microRNA (miRNA)s encapsulated in exosomes represent an important mechanism of communication between the cells. Exosomal miRNAs play an important role in oncogenesis via stimulating cell to cell communication and facilitating metastasis in cancers. Despite progressive advances, current methods for exosomal miRNA detection most rely on labor intensive sequencing approaches which are often prone to amplification bias and require costly and bulky equipment. Herein, we report an electrochemical approach for detection of cancer-derived exosomal miRNAs in human serum samples by selectively isolating the target miRNA using magnetic beads pre-functionalized with capture probes and then directly absorbing the targets onto the gold electrode surface. The level of adsorbed miRNA is detected electrochemically in the presence of the [Fe(CN)6]4-/3- redox system. This method enabled an excellent detection sensitivity of 1.0 pM with a relative standard deviation (%RSD) of <5.5% in cancer cells and serum samples (n = 8) collected from patients with colorectal adenocarcinoma. We believe that our approach could be useful for the quantification of exosomal miRNA in clinical samples.Griffith Sciences, School of Natural SciencesNo Full Tex
Quantum dot-based sensitive detection of disease specific exosome in serum
No full textTumor-derived exosomes have emerged as promising cancer biomarkers due to their unique composition and functions. Herein, we report a stripping voltammetric immunoassay for the electrochemical detection of disease-specific exosomes using quantum dots as signal amplifiers. The assay involves three subsequent steps where bulk exosome populations are initially magnetically captured on magnetic beads by a generic tetraspanin antibody (e.g., CD9 or CD63) followed by the identification of disease-specific exosomes using cancer-related. Here, we used CdSe quantum dot (CdSeQD) functionalised-biotinylated HER-2 and FAM134B antibodies as breast and colon cancer markers. After magnetic washing and purification steps, acid dissolution of CdSeQDs and subsequent anodic stripping voltammetric quantification of Cd2+ were carried out at the bare glassy carbon working electrode. This method enabled sensitive detection of 100 exosomes per μL with a relative standard deviation (%RSD) of <5.5% in cancer cell lines and a small cohort of serum samples (n = 9) collected from patients with colorectal adenocarcinoma. We believe that our approach could potentially represent an effective bioassay for the quantification of disease-specific exosomes in clinical samples.Griffith Sciences, School of Natural SciencesNo Full Tex
Pioneers of Library Movement in Pakistan
No full textThe paper aims to describe in brief the contribution of seven leaders of Pakistan librarianship, viz. K.B. Khalifa M. Asadullah, Prof. Dr. Abdul Moid, Dr. Abdus Subuh Qasimi, Muhammad Shafi, Fazal Elahi, Khawaja Nur Elahi and S. V. Hussain. The early library developments are given for better understanding of the role of these leaders
Alternating current electrohydrodynamics induced nanoshearing and fluid micromixing for specific capture of cancer cells
No full textwithin a few nanometers of an electrode surface. This force can be externally tuned via manipulating the applied ac-EHD field strength. The ability to manipulate ac-EHD induced forces and concomitant fluid micromixing can enhance fluid transport within the capture domain of the channel (e.g., transport of analytes and hence increase target-sensor interactions). This also provides a new capability to preferentially select strongly bound analytes over nonspecifically bound cells and molecules. To demonstrate the utility and versatility of nanoshearing phenomenon to specifically capture cancer cells, we present proof-of-concept data in lysed blood using two microfluidic devices containing a long array of asymmetric planar electrode pairs. Under the optimal experimental conditions, we achieved high capture efficiency (e.g., approximately 90%; %RSD=2, n=3) with a 10-fold reduction in nonspecific adsorption of non-target cells for the detection of whole cells expressing Human Epidermal Growth Factor Receptor 2 (HER2). We believe that our ac-EHD devices and the use of tuneable nanoshearing phenomenon may find relevance in a wide variety of biological and medical applications
Tuneable “Nano-Shearing”: a physical mechanism to displace nonspecific cell adhesion during rare cell detection
No full textWe report a tunable alternating current electro-hydrodynamic (ac-EHD) force which drives lateral fluid motion within a few nanometers of an electrode surface. Because the magnitude of this fluid shear force can be tuned externally (e.g., via the application of an ac electric field), it provides a new capability to physically displace weakly (nonspecifically) bound cellular analytes. To demonstrate the utility of the tunable nanoshearing phenomenon, we present data on purpose-built microfluidic devices that employ ac-EHD force to remove nonspecific adsorption of molecular and cellular species. Here, we show that an ac-EHD device containing asymmetric planar and microtip electrode pairs resulted in a 4-fold reduction in nonspecific adsorption of blood cells and also captured breast cancer cells in blood, with high efficiency (approximately 87%) and specificity. We therefore feel that this new capability of externally tuning and manipulating fluid flow could have wide applications as an innovative approach to enhance the specific capture of rare cells such as cancer cells in blood
RNA biomarkers: diagnostic and prognostic potentials and recent developments of electrochemical biosensors
No full textRibonucleic acids (RNAs) are considered as effective and minimally invasive biomarkers for disease diagnosis and prognosis due to their critical role in the regulation of different cellular processes. Over the past several years, the rapid progress in RNA biomarker research has resulted in the development of a large number of high-performance RNA-detection methods. Most of these methods are based on molecular-biology techniques such as quantitative reverse transcription polymerase chain reaction (RT-qPCR), microarrays, and RNA sequencing. In recent years, considerable attention has also been dedicated to developing RNA biosensors, exploiting micro-and nanofabrication technologies, and various readout strategies, including electrochemical and optical transducers. Here, the recent developments of RNA biosensors are concisely reviewed with a special emphasis on electrochemical-detection approaches. The following points are also highlighted: i) all the types of clinically relevant RNAs (mRNAs, miRNAs, lncRNAs) and their diagnostic and prognostic potential in cancer are outlined, ii) major challenges associated with current techniques are identified, followed by a critical analysis of how these challenges have been addressed by different biosensing approaches, and iii) the current requirements that still need to be met for effective screening of RNA biomarkers in both research and clinical settings
Conversion of African Americans to Islam : a sociological analysis of the Nation of Islam and associated groups
No full text'Conversion of African Americans to Islam: A Sociological Analysis of the Nation of
Islam Associated groups' is an empirical study of the religious experience of people
who had/have distinctive features in terms of race, ethnicity and historical experience.
The purpose of this thesis is to demonstrate how African Americans' (AAs) conversion
experience in general, and the Nation of Islam associated groups' conversion in
particular, differ from the studies of recruitment and conversion in the sociology of
religion and New Religion Movements (NRMs). More specifically, their recruitment
and conversion experiences to Islam diverge from those who converted to mainstream
Islam. The study investigates how AAs' historical experience, soci-economic
difficulties and the racism they encountered shaped and influenced their religious
understanding.
Research methods involved participant observations, a survey questionnaire, interviews,
conversations, personal communications and correspondence. To collect ethnographic
data eleven months field research was conducted mainly in the Chicago area and on two
short visits to Detroit, and three years continued communications with Muslim officials
and academics in the area. During the field research and afterwards through personal
communication 181 survey questionnaire responses were received, and 23 Muslim
officials, academics and ordinary Muslims were interviewed through semi-structured,
unstructured interviews, conversation and correspondence.
The thesis begins with a brief history of Islam and Muslims in general and the African
American Muslims (AAMs) in particular. More emphasis is given on the historical
development of the Nation of Islam (NOl). Then in Chapter III, discussions of schisms
in the history of the NOT are examined from sociological perspectives of social and
religious movements. In Chapter IV I aimed to formulate my own perspective to
analyse and study the conversion experiences of AAMs to Islam. I used a multivariate
approach, considering selectively widely held conversion and recruitment theories in the
sociology of the religion. I consider in Chapter V the predisposing conditions for AAMs
that influence their decision-making to join in the NOT, for example, political and
nationalistic sentiments and socio-economic deprivations. In Chapter VI I have applied
different terms to describe their religious experiences, such as conversion, alteration and
reversion. I have analysed further their encounters with the NOT, the methods of
recruitment they used and their major motives for joining the NOT and converting to
Tslam. In the concluding chapters (Chapter VII VTTT) I describe the different responses
of AAMS to Islam following the death of Elijah Muhammad. It is found out that the
Islamic appeal has polarised. While Farakhan's NOT appeared to continue the tradition
and style of the old NOI with the emphasis on nationalistic and socio-economic factors,
Tmam W. D. Mohammed's community turned more to the religious and spiritual aspects
of Tslam. These different approaches led to a polarisation of the appeal of Tslam to
AAMS.
This thesis contributes to knowledge in four key areas; the sociology of religion and
religious movements, the sociology of social and nationalistic movements, religious and
Islamic studies
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