304 research outputs found
Mind the Gap: Mentoring, Goal-setting and Self-Evaluation for International Graduate Students
The objective of this paper is to understand how peer mentoring and exercises to encourage goal-setting and self-evaluation can support first year international graduate students to engage in Canadian universities’ online learning environment during COVID-19. Surveys, students’ work, and instructors’ reflections were used to inform the current study. Preliinary findings show that during COVID-19, online peer mentoring and exercises to encourage goal-setting and self-evaluation have been able to support international students’ behavioural, cognitive and emotional engagement in Canadian academic learning to a certain degree. The findings also show that there is a need to use real-time communication tools to enhance the e-peer mentoring process for international students in an online course environment. Although the personal goal-setting exercises were new experiences for many of the international students, they proved to be valuable steps in their adaptation to Canadian graduate studies
Epstein-Barr virus Latent Membrane Protein LMP1 reduces p53 protein levels independent of the PI3K-Akt pathway
<p>Abstract</p> <p>Background</p> <p>Nasopharyngeal carcinoma (NPC) is an epithelial malignancy, which commonly occurs in Southern China, Taiwan, North Africa and Southeast Asia. Nasopharyngeal carcinoma is strongly associated with Epstein-Barr virus infection. The p53 tumour suppressor protein is rarely mutated in NPC suggesting that the inactivation of p53 pathway in NPC could be due to the presence of EBV proteins. The aim of this work was to determine the effects of EBV proteins namely LMP1 and LMP2A on the expression levels of p53 protein.</p> <p>Findings</p> <p>In this work we found that LMP1, but not LMP2A, decreased p53 protein levels. Overexpression of LMP1 resulted in increased ubiquitination of p53 suggesting that the decreased p53 protein levels by LMP1 was due to increased degradation of the protein. The reduction of p53 protein levels was independent of the PI3K-Akt pathway.</p> <p>Conclusions</p> <p>LMP1, but not LMP2A, reduced p53 protein levels through the increase in the polyubiquitination of p53 protein and was independent of the PI3K-Akt pathway.</p
A Storm in a "T" Cup
We revisit the process of transversification and agglomeration of particle
momenta that are often performed in analyses at hadron colliders, and show that
many of the existing mass-measurement variables proposed for hadron colliders
are far more closely related to each other than is widely appreciated, and
indeed can all be viewed as a common mass bound specialized for a variety of
purposes.Comment: 3 pages, 2 figures, presented by K.C. Kong at the 19th Particles and
Nuclei International Conference, PANIC 2011, MIT, Cambridge, MA (July 24-29,
2011
Pathogenic role of exosomes in Epstein-Barr Virus (EBV)-associated cancers
Exosomes are 40- to 100-nm membrane-bound small vesicles that carry a great variety of cellular
cargoes including proteins, DNA, messenger RNAs (mRNAs), and microRNAs (miRNAs). These nanovesicles are detected in various biological fluids such as serum, urine, saliva, and seminal fluids. Exosomes serve as key mediators in intercellular communication by facilitating the transfer and
exchange of cellular components from cells to cells. They contain various pathogenic factors whereby their adverse effects have been implicated in multiple viral infections and cancers. Interestingly, accumulating evidences showed that exosomes derived from tumour viruses or
oncoviruses, exacerbate virus-associated cancers by remodelling the tumour microenvironment. In this review, we summarize the contributing factors of Epstein-Barr virus (EBV) products-containing exosomes in viral pathogenesis and their potential implications in EBV-driven
malignancies. Understanding the biological role of these exosomes in the disease would undoubtedly boost the development of a more comprehensive strategy to combat EBV-associated cancers and to better predict the therapeutic outcomes. Furthermore, we also highlight the potentials and challenges of EBV products-containing exosomes being employed as diagnostic markers and therapeutic targets for EBV-related cancers. Since these aspects are rather
underexplored, we attempt to underline interesting areas that warrant further investigations in the future
Hepatitis B Virus and B-cell lymphoma: evidence, unmet need, clinical impact, and opportunities
Nearly a billion people worldwide are infected with the hepatitis B Virus (HBV) and about a third of them have chronic infection. HBV is an important cause of morbidity and mortality, including acute and chronic hepatitis and hepatocellular carcinoma (HCC). Screening and control of primary HBV infection through vaccination represent a major advance in global public health, but large sections of the world population, in both developed and underdeveloped countries, remain unscreened and unvaccinated. In addition to being a global cause of liver disease, an important role of HBV in lymphoma has also emerged. First, the high risk of HBV reactivation in previously infected patients receiving chemo-immunotherapy necessitates the systematic evaluation of HBV serological status in all non-Hodgkin's lymphoma (NHL) cases and preemptive antiviral therapy for those who may have chronic or occult HBV infection. Second, HBV has been shown to infect lymphocytes, namely B-cells, and has been associated with a higher risk of developing B-cell lymphoma, most clearly in countries where HBV is endemic. While the risk of HBV reactivation with chemoimmunotherapy in NHL is well known, the role and the impact of HBV as a global lymphoma risk factor and potential oncogenic driver in B-cells are very poorly understood. Here, we review the clinical and scientific evidence supporting an association between HBV and B-cell lymphoma, with a particular focus on diffuse large B-cell lymphoma (DLBCL) and provide an overview of the estimated impact of HBV infection on the biology and clinical course of DLBCL. We also discuss ways to gain a better insight into the unmet need posed by HBV in lymphoma and whether assessing immune responses to HBV, measuring viral loads, and detecting the presence of HBV-encoded proteins in tumor tissue could be integrated into the molecular and clinical risk stratification of patients with DLBCL
Intra- and Inter-specific variation of four Acetess species (Crustacea: Decapoda: Sergestidae) sampled along the West Coast of Peninsular Malaysia
The intra- and inter-specific variation of Acetes shrimps were evaluated based on samples collected from in-shore catches and off-shore trawling around the west coast of Peninsular Malaysia. Species captured were identified as Acetes indicus, A. serrulatus, A. japonicus and A. sibogae. A region of the mitochondrial cytochrome c oxidase subunit I (COI) gene comprising 552 base pairs (bp) was amplified from 159 Acetes specimens. The sequence alignment analysis generated phylogenetic trees which depicted the four major clades that were consistent with the species identified morphologically. These four species varied considerably for haplotype and nucleotide diversity, with A. indicus and A. serrulatus showing different demographic histories. Furthermore, the observation of two clades in the A. indicus and A. sibogae lineages, with relatively high levels of intraspecific divergence, suggests that cryptic diversity is possibly present in these two taxa. This study has contributed to the knowledge of the distribution patterns and molecular phylogenetics of four Acetes spp. in the Straits of Malacca
Exosomes in Human Immunodeficiency Virus Type I Pathogenesis: Threat or Opportunity?
Nanometre-sized vesicles, also known as exosomes, are derived from endosomes of diverse cell types and present in multiple
biological fluids. Depending on their cellular origins, the membrane-bound exosomes packed a variety of functional proteins
and RNA species. These microvesicles are secreted into the extracellular space to facilitate intercellular communication. Collective
findings demonstrated that exosomes fromHIV-infected subjects sharemany commonalities withHuman ImmunodeficiencyVirus
Type I (HIV-1) particles in terms of proteomics and lipid profiles. These observations postulated that HIV-resembled exosomes
may contribute to HIV pathogenesis. Interestingly, recent reports illustrated that exosomes from body fluids could inhibit HIV
infection, which then bring up a new paradigm for HIV/AIDS therapy. Accumulative findings suggested that the cellular origin of
exosomes may define their effects towards HIV-1. This review summarizes the two distinctive roles of exosomes in regulating HIV
pathogenesis. We also highlighted several additional factors that govern the exosomal functions. Deeper understanding on how
exosomes promote or abate HIV infection can significantly contribute to the development of new and potent antiviral therapeutic
strategy and vaccine designs
Antibacterial Action of Curcumin against Staphylococcus aureus: A Brief Review
Curcumin, the major constituent of Curcuma longa L. (Zingiberaceae family) or turmeric, commonly used for cooking in Asian
cuisine, is known to possess a broad range of pharmacological properties at relatively nontoxic doses. Curcumin is found to be
effective against Staphylococcus aureus (S. aureus). As demonstrated by in vitro experiment, curcumin exerts even more potent
effects when used in combination with various other antibacterial agents. Hence, curcumin which is a natural product derived
fromplant is believed to have profoundmedicinal benefits and could be potentially developed into a naturally derived antibiotic in
the future. However, there are several noteworthy challenges in the development of curcumin as a medicine. S. aureus infections,
particularly those caused by themultidrug-resistant strains, have emerged as a global health issue and urgent action is needed.This
review focuses on the antibacterial activities of curcumin against both methicillin-sensitive S. aureus (MSSA) and methicillinresistant
S. aureus (MRSA). We also attempt to highlight the potential challenges in the effort of developing curcumin into a
therapeutic antibacterial agent
Potential Role of Oxidative Stress-Induced Apoptosis in Mediating Chromosomal Rearrangements in Nasopharyngeal Carcinoma
Abstract
Background
Genetic aberrations have been identified in nasopharyngeal carcinoma (NPC), however, the underlying mechanism remains elusive. There are increasing evidences that the apoptotic nuclease caspase-activated deoxyribonuclease (CAD) is one of the players leading to translocation in leukemia. Oxidative stress, which has been strongly implicated in carcinogenesis, is a potent apoptotic inducer. Most of the NPC etiological factors are known to induce oxidative stress. Although apoptosis is a cell death process, cells possess the potential to survive apoptosis upon DNA repair. Eventually, the surviving cells may carry rearranged chromosomes. We hypothesized that oxidative stress-induced apoptosis may cause chromosomal breaks mediated by CAD. Upon erroneous DNA repair, cells that survive apoptosis may harbor chromosomal rearrangements contributing to NPC pathogenesis. This study focused on the AF9 gene at 9p22, a common deletion region in NPC. We aimed to propose a possible model for molecular mechanism underlying the chromosomal rearrangements in NPC.
Results
In the present study, we showed that hydrogen peroxide (H2O2) induced apoptosis in
NPC (HK1) and normal nasopharyngeal epithelial (NP69) cells, as evaluated by flow cytometric analyses. Activity of caspases 3/7 was detected in H2O2-treated cells. This activity was inhibited by caspase inhibitor (CI). By nested Inverse Polymerase Chain Reaction (IPCR), we demonstrated that oxidative stress-induced apoptosis in HK1 and NP69 cells resulted in cleavages within the breakpoint cluster region (BCR) of the AF9 gene. The gene cleavage frequency detected in the H2O2-treated cells was found to be significantly higher than untreated control. We further found that treatment with CI, which indirectly inhibits CAD, significantly reduced the chromosomal breaks in H2O2-cotreated cells. Intriguingly, a few breakpoints were mapped within the AF9 region that was previously reported to translocate with the mixed lineage leukemia (MLL) gene in acute lymphoblastic leukemia (ALL) patient.
Conclusions
In conclusion, our findings suggested that oxidative stress-induced apoptosis could be one of the mechanisms underlying the chromosomal rearrangements in NPC. CAD may play an important role in chromosomal cleavages mediated by oxidative stress-induced apoptosis. A potential model for oxidative stress-induced apoptosis mediating chromosomal rearrangements in NPC is proposed
Expression Trend of Selected Ribosomal Protein Genes in Nasopharyngeal Carcinoma
Ribosomal proteins are traditionally associated with protein biosynthesis until recent studies that implicated their extraribosomal functions in human diseases and cancers. Our previous studies using GeneFishingTM DEG method and microarray revealed underexpression
of three ribosomal protein genes, RPS26, RPS27, and RPL32 in cancer of the nasopharynx. Herein, we investigated the expression pattern and nucleotide sequence integrity of these genes in nasopharyngeal carcinoma to further delineate their involvement in tumourigenesis. The
relationship of expression level with clinicopathologic factors was also statistically studied
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