δ- and γ-tocotrienols induce classical ultrastructural apoptotic changes in human T lymphoblastic leukemic cells.

Tocotrienols are isomers of the vitamin E family, which have been reported to exert cytotoxic effects in various cancer cells. Although there have been some reports on the effects of tocotrienols in leukemic cells, ultrastructural evidence of tocotrienol-induced apoptotic cell death in leukemic cells is lacking. The present study investigated the effects of three isomers of tocotrienols (alpha, delta, and gamma) on a human T lymphoblastic leukemic cell line (CEM-SS). Cell viability assays showed that all three isomers had cytotoxic effects (p < 0.05) on CEM-SS cells with delta-tocotrienol being the most potent. Transmission electron microscopy showed that the cytotoxic effects by delta- and gamma-tocotrienols were through the induction of an apoptotic pathway as demonstrated by the classical ultrastructural apoptotic changes characterized by peripheral nuclear chromatin condensation and nuclear fragmentation. These findings were confirmed biochemically by the demonstration of phosphatidylserine externalization via flow cytometry analysis. This is the first study showing classical ultrastructural apoptotic changes induced by delta- and gamma-tocotrienols in human T lymphoblastic leukemic cells.

Leukaemic stem cells: drug resistance, metastasis and therapeutic implications.

Although there have been many new developments in the treatment of leukaemia with the use of new anti-leukaemic agents and stem cell transplantation, drug resistance and treatment failure remain a great challenge for the attending physician. Several studies have suggested that leukaemic stem cells (LSCs) play a pivotal role in chemoresistance and metastasis and the mechanisms by which these cells do so have also been elucidated. There is increasing evidence to show that there exists a large pool of therapeutic targets in LSCs and that the eradication of these cells is feasible with some promising results. This article gives an overview of different types of cancer stem cells (CSCs) derived from various types of leukaemia, the mechanisms by which LSCs contribute to drug resistance and metastasis and some recent advances in targeted therapy against LSCs.

Mesenchymal stem cells: angels or demons?

Mesenchymal stem cells (MSCs) have been used in cell-based therapy in various disease conditions such as graft-versus-host and heart diseases, osteogenesis imperfecta, and spinal cord injuries, and the results have been encouraging. However, as MSC therapy gains popularity among practitioners and researchers, there have been reports on the adverse effects of MSCs especially in the context of tumour modulation and malignant transformation. These cells have been found to enhance tumour growth and metastasis in some studies and have been related to anticancer-drug resistance in other instances. In addition, various studies have also reported spontaneous malignant transformation of MSCs. The mechanism of the modulatory behaviour and the tumorigenic potential of MSCs, warrant urgent exploration, and the use of MSCs in patients with cancer awaits further evaluation. However, if MSCs truly play a role in tumour modulation, they can also be potential targets of cancer treatment.

Inflammation in COVID-19: from pathogenesis to treatment.

The coronavirus disease 2019 (COVID-19) was declared a pandemic in March 2020 by the World Health Organization (WHO). To date, there were > 163 million confirmed cases of COVID-19 and the disease has claimed > 3.3 million lives globally. As with many other diseases, inflammation is a key feature of COVID-19. When inflammation is overwhelming, it may lead to unfavorable outcomes or even death. Scientists all over the world are working tirelessly in search of therapeutic strategies to suppress or modulate inflammation in COVID-19. This review gives an overview of the role of inflammation in COVID-19. It also critically examines the various treatment approaches that target the immune system and inflammation in COVID-19, as well as highlights the key findings in the numerous studies conducted thus far.

The SARS-CoV-2 Outbreak: an Epidemiological and Clinical Perspective.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak started with the detection of an increasing number of pneumonia cases of unknown origin in Wuhan, China, since December 2019. The disease caused by SAS-CoV-2 was subsequently named coronavirus disease 2019 (COVID-19). Currently, the ongoing COVID-19 pandemic poses a global health concern with more than 28.9 million confirmed cases, taking away the lives of more than 900,000 people worldwide. To prevent further spread of the disease, an understanding of the clinical characteristics and how the disease spread is essential, especially for an emerging disease like COVID-19. Individuals who are infected with SARS-CoV-2 show diverse clinical features, and the disease severity can range from asymptomatic to death. The disease has been shown to affect not just the respiratory system but also other systems of the body. This review will discuss the pulmonary and extra-pulmonary clinical manifestations of COVID-19 in general, as well as the clinical characteristics in different groups of patients such as children, the elderly, pregnant women, patients with comorbidities and those with a compromised immunity. It will also critically examine existing evidence from relevant studies and discuss the SARS-CoV-2 outbreak from an epidemiological perspective. With the easing of control measures in many countries after months of lockdown, it is important to revisit the lessons learnt from research, as the world enters a new normal with the coexistence of SARS-CoV-2.

A time-resolved fluorescent lanthanide (Eu)-GTP binding assay for chemokine receptors as targets in drug discovery.

Chemokines are a family of chemoattractant cytokines involved in leukocyte trafficking, activation, development, and hematopoeisis. Chemokines and their receptors have been implicated in several disease processes, particularly inflammatory and autoimmune disorders and cancer, and are therefore attractive targets for drug development. Chemokine receptors are members of the seven-transmembrane, G protein-coupled receptor (GPCR) family. As such they can be studied using GPCR assays such as ligand binding, G protein activation, and downstream signaling processes such as intracellular calcium flux. In this respect assessing GPCR activation by GTP binding is an important tool to study the early stage of signal transduction. Previously this has been done using the radiolabeled non-hydrolyzable GTP analogue [(35)S]GTPgammaS. In order to avoid the problems involved in working with radioactivity, a new non-radioactive version of the assay has been developed using a europium-labeled GTP analogue in which europium-GTP binding can be assayed using time-resolved fluorescence. We have adapted this assay for chemokine receptors. In this chapter, using the chemokine receptor CXCR4 as an example, we describe the steps for assay optimization. In addition we describe adaptation of this assay for the high-throughput screening of chemokine antagonists.

Role of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) in Cancer Prevention and Cancer Promotion.

The nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed by medical practitioners in many clinical conditions for the symptomatic treatment of pain and fever. Due to their anti-inflammatory properties, these drugs have been investigated for their anticancer effects in numerous studies. This is because chronic inflammation has long been linked to carcinogenesis. As such, anti-inflammatory drugs are believed to play a role in cancer treatment and prevention. In the past few decades, research has shown that NSAIDs may decrease the risk of certain types of cancer. However, there is also a growing body of research that proves the contrary. Furthermore, NSAIDs are well known for many side effects, including some life-threatening ones. This review will discuss the relationship between chronic inflammation and cancer, the role of NSAIDs in cancer prevention and cancer promotion, and some of the potentially lethal side effects of these drugs.

Disease-Modifying Effects of Long-Term and Continuous Use of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) in Spondyloarthritis.

Spondyloarthritis or spondyloarthropathy (SpA) is a group of related rheumatic disorders, which presents with axial and nonaxial features, affecting structures within the musculoskeletal system, as well as other bodily systems. Both pharmacological and nonpharmacological therapeutic options are available for SpA. For decades, nonsteroidal anti-inflammatory drugs (NSAIDs) have been used as the first-line drugs to treat the disease. Research has shown that other than pain relief, NSAIDs have disease-modifying effects in SpA. However, to achieve these effects, continuous and/or long-term NSAID use is usually required. This review will give an overview of SpA, discuss NSAIDs and their disease-modifying effects in SpA, and highlight some of the important adverse effects of long-term and continuous NSAID use, particularly those related to the gastrointestinal, renal, and cardiovascular systems.

Comparison of the potential multiple binding modes of bicyclam, monocylam, and noncyclam small-molecule CXC chemokine receptor 4 inhibitors.

CXC chemokine receptor (CXCR)4 is an HIV coreceptor and a chemokine receptor that plays an important role in several physiological and pathological processes, including hematopoiesis, leukocyte homing and trafficking, metastasis, and angiogenesis. This receptor belongs to the class A family of G protein-coupled receptors and is a validated target for the development of a new class of antiretroviral therapeutics. This study compares the interactions of three structurally diverse small-molecule CXCR4 inhibitors with the receptor and is the first report of the molecular interactions of the nonmacrocyclic CXCR4 inhibitor (S)-N'-(1H-benzimidazol-2-ylmethyl)-N'-(5,6,7,8-tetrahydroquinolin-8-yl)butene-1,4-diamine (AMD11070). Fourteen CXCR4 single-site mutants representing amino acid residues that span the entire putative ligand binding pocket were used in this study. These mutants were used in binding studies to examine how each single-site mutation affected the ability of the inhibitors to compete with (125)I-stromal-derived factor-1alpha binding. Our data suggest that these CXCR4 inhibitors bind to overlapping but not identical amino acid residues in the transmembrane regions of the receptor. In addition, our results identified amino acid residues that are involved in unique interactions with two of the CXCR4 inhibitors studied. These data suggest an extended binding pocket in the transmembrane regions close to the second extracellular loop of the receptor. Based on site-directed mutagenesis and molecular modeling, several potential binding modes were proposed for each inhibitor. These mechanistic studies might prove to be useful for the development of future generations of CXCR4 inhibitors with improved clinical pharmacology and safety profiles.

Interdisciplinary and inter-institutional differences in learning preferences among Malaysian medical and health sciences students.

INTRODUCTION: The learner-centred approach in medical and health sciences education makes the study of learning preferences relevant and important. This study aimed to investigate the interdisciplinary, inter-institutional, gender and racial differences in the preferred learning styles among Malaysian medical and health sciences students in three Malaysian universities, namely SEGi University (SEGi), University of Malaya (UM) and Universiti Tunku Abdul Rahman (UTAR). It also investigated the differences in the preferred learning styles of these students between high achievers and non-high achievers. METHODS: This cross-sectional study was carried out on medical and health sciences students from three Malaysian universities following the approval of the Research and Ethics Committee, SEGi University. Purposive sampling was used and the preferred learning styles were assessed using the VARK questionnaire. The questionnaire was validated prior to its use. Three disciplines (medicine, pharmacy and dentistry) were chosen based on their entry criteria and some similarities in their course structure. The three participating universities were Malaysian universities with a home-grown undergraduate entry medical program and students from a diverse cultural and socioeconomic background. The data were analysed using the Statistical Package for the Social Sciences (SPSS) software, version 22. VARK subscale scores were expressed as mean+standard deviation. Comparisons of the means were carried out using t-test or ANOVA. A p value of <0.05 was considered as statistically significant, and <0.001 as highly significant. RESULTS: Both statistically significant interdisciplinary and inter-institutional differences in learning preferences were observed. Out of the 337 students, a majority of the participants were unimodal learners (n=263, 78.04%). The most common type of learners was the reading/writing type (n=92, 27.30%) while the kinesthetic subscale (M=6.98, SD=2.85) had the highest mean score. Female students (M=6.86, SD=2.86) scored significantly higher than male students (M=6.08, SD=2.41; t(249), p=0.014) in the auditory subscale, whereas Chinese students (M=5.87, SD=2.65) scored significantly higher than Malay students (M=4.70, SD=2.87; p=0.04) in the visual subscale. However, the mean VARK subscale scores did not differ significantly between high achievers and non-high achievers (p>0.05). CONCLUSION: This study gives an insight into the learner characteristics of more than one medical school in Malaysia. Such multi-institutional studies are lacking in the published literature and this study gives a better representation of the current situation in the learning preferences among medical students in Malaysia.

Characterization of the molecular pharmacology of AMD3100: a specific antagonist of the G-protein coupled chemokine receptor, CXCR4.

The chemokine receptor CXCR4 is widely expressed on different cell types, is involved in leukocyte chemotaxis, and is a co-receptor for HIV. AMD3100 has been shown to be a CXCR4 receptor antagonist, and to block HIV infection of T-tropic, X4-using, virus in vitro and in vivo. AMD3100 is an effective mobilizer of hematopoietic stem cells and is being investigated in clinical trials in multiple myeloma and non-Hodgkins lymphoma patients. Using the CCRF-CEM T-cell line that constitutively expresses CXCR4 we confirmed that AMD3100 was an antagonist of SDF-1/CXCL12 ligand binding (IC50=651+/-37 nM). We have also shown that AMD3100 inhibits SDF-1 mediated GTP-binding (IC50=27+/-2.2 nM), SDF-1 mediated calcium flux (IC50=572+/-190 nM), and SDF-1 stimulated chemotaxis (IC50=51+/-17 nM). AMD3100 did not inhibit calcium flux against cells expressing CXCR3, CCR1, CCR2b, CCR4, CCR5 or CCR7 when stimulated with their cognate ligands, nor did it inhibit receptor binding of LTB4. AMD3100 did not, on its own, induce a calcium flux in the CCRF-CEM cells, which express multiple GPCRs including CXCR4, CCR4 and CCR7. Furthermore, AMD3100 neither stimulated GTP-binding, an assay for GPCR activation, in CEM cell membranes; nor chemotaxis of CCRF-CEM cells. These data therefore demonstrate that AMD3100 is a specific antagonist of CXCR4, is not cross-reactive with other chemokine receptors, and is not an agonist of CXCR4.

Linker-insertion mutagenesis of Pseudomonas aeruginosa outer membrane protein OprF.

The oprF gene, expressing Pseudomonas aeruginosa major outer membrane protein OprF, was subjected to semi-random linker mutagenesis by insertion of a 1.3 kb Hincll kanamycin-resistance fragment from plasmid pUC4KAPA into multiple blunt-ended restriction sites in the oprF gene. The kanamycin-resistance gene was then removed by Pstl digestion, which left a 12 nucleotide pair linker residue. Nine unique clones were identified that contained such linkers at different locations within the oprF gene and were permissive for the production of full-length OprF variants. In addition, one permissive site-directed insertion, one non-permissive insertion and one carboxy-terminal insertion leading to proteolytic truncation were also identified. These mutants were characterized by DNA sequencing and reactivity of the OprF variants with a bank of 10 OprF-specific monoclonal antibodies. Permissive clones produced OprF variants that were shown to be reactive with the majority of these monoclonal antibodies, except where the insertion was suspected of interrupting the epitope for the specific monoclonal antibody. In addition, these variants were shown to be 2-mercaptoethanol modifiable, to be resistant to trypsin cleavage in intact cells and partly cleaved to a high-molecular-weight core fragment in outer membranes and, where studied, to be accessible to indirect immunofluorescenee labelling in intact cells by monoclonal antibodies specific for surface epitopes. Based on these data, a revised structural model for OprF is proposed.

Role of stem cells in spondyloarthritis: Pathogenesis, treatment and complications.

Spondyloarthritis (SpA) is a family of interrelated inflammatory arthritis that includes ankylosing spondylitis (AS), psoriatic arthritis, reactive arthritis, arthritis related to inflammatory bowel disease and undifferentiated SpA. The classification, epidemiology, pathogenesis and treatment of SpA have been extensively reviewed in the published literature. Reviews on the use of stem cells in various autoimmune diseases in general are also common. However, a review on the role of stem cells in SpA is currently lacking. This review focuses on the involvement of stem cells in the pathogenesis of SpA and the application of different types of stem cells in the treatment of SpA. It also addresses some of the complications which may arise as a result of the use of stem cells in the treatment of SpA.

An unusual case of bilateral vestibulopathy, chronic subjective dizziness and spondyloarthropathy.

OBJECTIVE: Vertigo and dizziness are two common symptoms seen in everyday practice. However, in some cases, making a diagnosis can be challenging. This case report shows the relevance of a careful psychiatric history, which led to the diagnosis of chronic subjective dizziness associated with bilateral peripheral vestibulopathy. METHODS: A case of a 33-year-old lady with multiple episodes of vertigo attack after a minor head injury is reported. RESULTS: A comprehensive audiometric and vestibular evaluation reviewed bilateral peripheral vestibulopathy. The frequency of the vertigo attacks decreased after treatment with betahisdine, but the patient still experienced chronic dizziness. Interestingly, when she developed spondyloarthropathy (SpA) 2 years later, both the vertigo and dizziness disappeared. When the patient went into clinical remission for SpA, she once again felt the vertigo and dizziness. The symptoms were initially thought to be part of the autoimmune disease. However, a course of oral prednisolone was ineffective. She was later diagnosed with agoraphobia without panic attack and chronic subjective dizziness, and was successfully treated with a course of benzodiazepine. CONCLUSION: The case presented demonstrates the importance of a biopsychosocial approach to patient management as vertigo and dizziness are often accompanied by psychological problems that must not be overlooked.

Identification of enteric pathogens by heat shock protein 60 kDa (HSP60) gene sequences.

A highly specific and reproducible approach for the simultaneous detection of enteric pathogenic bacteria was developed using bacterial hsp60 gene and molecular biological tools. A single pair of universal primers was derived from the highly conserved sequence of hsp60 genes encompassing a 600-bp hypervariable region. PCR amplification followed by either dot blot hybridization or restriction enzyme digestion performed on 38 enteric bacteria indicated that this approach could differentiate not only different genera such as Campylobacter, Yersinia and Vibrio, but also species that are closely related genetically, such as between C. jejuni and C. coli, or between Salmonella and Shigella or Escherichia coli.

Role of mesenchymal stem cells in leukaemia: Dr. Jekyll or Mr. Hyde?

Mesenchymal stem cells (MSCs) have captured the attention of researchers today due to their multipotent differentiation capacity. Also, they have been successfully applied clinically, in the treatment of various diseases of the heart and musculoskeletal systems, with encouraging results. Their supportive role in haematopoiesis and their anti-inflammatory and immunomodulatory properties have enhanced their contribution towards the improvement of engraftment and the treatment of graft-versus-host disease in patients receiving haematopoietic stem cell transplantation. However, there is a growing body of research that supports the involvement of MSCs in leukaemogenesis with several genetic and functional abnormalities having been detected in the MSCs of leukaemia patients. MSCs also exert leukaemia-enhancing effects and induce chemotherapy resistance in leukaemia cells. This paper addresses the key issues in the therapeutic value as well as the harmful effects of the MSCs in leukaemia with a sharp focus on the recent updates in the published literature.

Edible bird's nest: food or medicine?

Edible bird's nest (EBN) is derived from the saliva of certain types of swiftlets. It is consumed in many parts of the world for its nutritional and medicinal values. Although many claims have been made on the therapeutic and health-promoting effects of EBN, scientific documentations regarding these effects are very limited in published literature. It is not until recently that the biological effects of EBN are being investigated and evidence-based studies are being conducted. Several studies have found that EBN may enhance cell proliferation and differentiation and various beneficial effects have been reported in vitro as well as in vivo. While these studies point towards the potential use of EBN in the treatment or even prevention of several diseases, the mechanisms of action of EBN remain largely unknown and more explorations are needed. This review is one of the very few scientific reviews on EBN which focuses on recent evidence-based discoveries.

Tocotrienol research: past into present.

The vitamin E family consists of eight isomers known as alpha-, beta-, gamma-, and delta-tocopherols and alpha-, beta-, gamma-, and delta-tocotrienols. Numerous studies focused on the health benefits of these isomers have been performed since the discovery of vitamin E in 1922. Recent discoveries on the potential therapeutic applications of tocotrienols have revolutionized vitamin E research. Nevertheless, despite the abundance of literature, only 1% of vitamin E research has been conducted on tocotrienols. Many new advances suggest that the use of tocotrienols for health improvement or therapeutic purposes is promising. Although the mechanisms of action of tocotrienols in certain disease conditions have been explored, more detailed investigations into the fundamentals of the health-promoting effects of these molecules must be elucidated before they can be recommended for health improvement or for the treatment or prevention of disease. Furthermore, many of the studies on the effects of tocotrienols have been carried out using cell lines and animal models. The effects in humans must be well established before tocotrienols are used as therapeutic agents in various disease conditions, hence the need for more evidence-based human clinical trials.

The molecular pharmacology of AMD11070: an orally bioavailable CXCR4 HIV entry inhibitor.

In order to enter and infect human cells HIV must bind to CD4 in addition to either the CXCR4 or the CCR5 chemokine receptor. AMD11070 was the first orally available small molecule antagonist of CXCR4 to enter the clinic. Herein we report the molecular pharmacology of AMD11070 which is a potent inhibitor of X4 HIV-1 replication and the gp120/CXCR4 interaction. Using the CCRF-CEM T cell line that endogenously expresses CXCR4 we have demonstrated that AMD11070 is an antagonist of SDF-1α ligand binding (IC50 = 12.5 ± 1.3 nM), inhibits SDF-1 mediated calcium flux (IC50 = 9.0 ± 2.0 nM) and SDF-1α mediated activation of the CXCR4 receptor as measured by a Eu-GTP binding assay (IC50 =39.8 ± 2.5 nM) or a [(35)S]-GTPγS binding assay (IC50 =19.0 ± 4.1 nM), and inhibits SDF-1α stimulated chemotaxis (IC50 =19.0 ± 4.0 nM). AMD11070 does not inhibit calcium flux of cells expressing CXCR3, CCR1, CCR2b, CCR4, CCR5 or CCR7, or ligand binding to CXCR7 and BLT1, demonstrating selectivity for CXCR4. In addition AMD11070 is able to inhibit the SDF-1ß isoform interactions with CXCR4; and N-terminal truncated variants of CXCR4 with equal potency to wild type receptor. Further mechanistic studies indicate that AMD11070 is an allosteric inhibitor of CXCR4.