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  1. Current techniques in reprogramming cell potency
    Romli F, Alitheen NB, Hamid M, Ismail R, Abd Rahman NM
    J Cell Biochem, 2013 Jun;114(6):1230-7.
    PMID: 23239017 DOI: 10.1002/jcb.24477
    The first successful attempt to reprogram somatic cell into embryonic-like stem cell was achieved on 2006. Since then, it had sparked a race against time to bring this wonderful invention from bench to bedside but it is not easily achieved due to severe problems in term of epigenetic and genomic. With each problem arise, new technique and protocol will be constructed to try to overcome it. This review addresses the various techniques made available to create iPSC with problems hogging down the technique.
    Matched MeSH terms: Retroviridae/genetics; Lentivirus/genetics
  2. Fulltext Chromosomal abnormalities and reproductive outcome in Malaysian couples with miscarriages
    Pal S, Ma SO, Norhasimah M, Suhaida MA, Siti Mariam I, Ankathil R, et al.
    Singapore Med J, 2009 Oct;50(10):1008-12.
    PMID: 19907893
    This study was done to determine the prevalence of chromosomal abnormalities and the subsequent reproductive outcome in couples who had two or more miscarriages.
    Matched MeSH terms: Abortion, Spontaneous/genetics*; Chromosome Disorders/genetics
  3. Fulltext MECP2 mutations in Malaysian Rett syndrome patients
    Fong CB, Thong MK, Sam CK, Mohamed Noor MN, Ariffin R
    Singapore Med J, 2009 May;50(5):529-33.
    PMID: 19495527
    Rett syndrome (RS) is a severe neurodevelopmental disorder characterised by normal neurological development followed by progressive developmental regression. The X-linked dominant inheritance of RS has been mapped to the gene that encodes the methyl-CpG-binding protein-2 (MECP2) at Xq28. In the present study, denaturing high-performance liquid chromatography (DHPLC) was used to detect mutations in the MECP2 gene in 20 Malaysian RS patients.
    Matched MeSH terms: Rett Syndrome/genetics*; Methyl-CpG-Binding Protein 2/genetics*
  4. Fulltext Mutation analysis of the BRCA1 gene in Malaysian breast cancer patients
    Balraj P, Khoo AS, Volpi L, Tan JA, Nair S, Abdullah H
    Singapore Med J, 2002 Apr;43(4):194-7.
    PMID: 12188064
    Thirty patients with early onset breast cancer or familial breast cancer from Malaysia were analysed for germline mutation in the early onset breast cancer I gene (BRCA1). Direct sequencing of the entire coding region of BRCA1 identified a frameshift mutation, c.5447-5448insC (insC5447) (codon 1776 of exon 21) in a patient aged 32 of the Malay ethnic origin, who had no family history of breast and/or ovarian cancer. Eight polymorphisms (2201C > T, 2430T > C, P871L, E1038G, K1183R, 4427T > C, S1613G and IVS8-57delT) were identified in the samples tested.
    Matched MeSH terms: Breast Neoplasms/genetics*; Mutation/genetics*
  5. Fulltext Validation of a multiplex RT-PCR assay for screening significant oncogene fusion transcripts in children with acute lymphoblastic leukaemia
    Ariffin H, Chen SP, Wong HL, Yeoh A
    Singapore Med J, 2003 Oct;44(10):517-20.
    PMID: 15024455
    In childhood acute lymphoblastic leukaemia (ALL), cytogenetics play an important role in diagnosis, allocation of treatment and prognosis. Conventional cytogenetic analysis, involving mainly karyotyping in our experience, has not been successful in a large proportion of cases due to inadequate metaphase spreads and poor chromosome morphology. Our aim is to develop a highly sensitive and specific method to screen simultaneously for the four most frequent fusion transcripts resulting from specific chromosomal translocations, namely, both the CML- and ALLtype BCR-ABL transcripts of t(9;22), E2A-PBX1 transcript of t(1;19), the MLL-AF4 transcript of t(4;11) and TEL-AML1 (also termed ETV6-CBFA2) of the cryptic t(12;21). A multiplex reverse transcription polymerase chain reaction protocol (RT-PCR) was developed and tested out on archival bone marrow samples and leukaemia cell lines. In all samples with a known translocation detected by cytogenetic techniques, the same translocation was identified by the multiplex-PCR assay. Multiplex RT-PCR assay is an effective, sensitive, accurate and cost-effective diagnostic tool which can improve our ability to accurately and rapidly risk-stratify patients with childhood ALL.
    Matched MeSH terms: Oncogene Proteins, Fusion/genetics*; Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
  6. Fulltext DNA fingerprinting of methicillin-resistant Staphylococcus aureus by pulsed-field gel electrophoresis (PFGE): comparison of strains from 2 Malaysian hospitals
    Norazah A, Liew SM, Kamel AG, Koh YT, Lim VK
    Singapore Med J, 2001 Jan;42(1):15-9.
    PMID: 11361232
    To determine and compare the pulsed-field gel electrophoresis (PFGE) patterns of endemic MRSA strains in 2 major Malaysian hospitals and to compare the PFGE patterns with antibiotypes of the strains studied.
    Matched MeSH terms: Staphylococcus aureus/genetics*; Methicillin Resistance/genetics*
  7. Fulltext The rs9340799 polymorphism of the estrogen receptor alpha (ESR1) gene and its association with breast cancer susceptibility
    Tan SC, Low TY, Mohamad Hanif EA, Sharzehan MAK, Kord-Varkaneh H, Islam MA
    Sci Rep, 2021 Sep 20;11(1):18619.
    PMID: 34545128 DOI: 10.1038/s41598-021-97935-8
    The ESR1 rs9340799 polymorphism has been frequently investigated with regard to its association with breast cancer (BC) susceptibility, but the findings have been inconclusive. In this work, we aimed to address the inconsistencies in study findings by performing a systematic review and meta-analysis. Eligible studies were identified from the Web of Science, PubMed, Scopus, China National Knowledge Infrastructure, VIP and Wanfang databases based on the predefined inclusion and exclusion criteria. The pooled odds ratio (OR) was then calculated under five genetic models: homozygous (GG vs. AA), heterozygous (AG vs. AA), dominant (AG + GG vs. AA), recessive (GG vs. AA + AG) and allele (G vs. A). Combined results from 23 studies involving 34,721 subjects indicated a lack of significant association between the polymorphism and BC susceptibility (homozygous model, OR = 1.045, 95% CI 0.887-1.231, P = 0.601; heterozygous model, OR = 0.941, 95% CI 0.861-1.030, P = 0.186; dominant model, OR = 0.957, 95% CI 0.875-1.045, P = 0.327; recessive model, OR = 1.053, 95% CI 0.908-1.222, P = 0.495; allele model, OR = 0.987, 95% CI 0.919-1.059, P = 0.709). Subgroup analyses by ethnicity, menopausal status and study quality also revealed no statistically significant association (P > 0.05). In conclusion, our results showed that the ESR1 rs9340799 polymorphism was not associated with BC susceptibility, suggesting its limited potential as a genetic marker for BC.
    Matched MeSH terms: Breast Neoplasms/genetics*; Estrogen Receptor alpha/genetics*
  8. Fulltext A guide in lentiviral vector production for hard-to-transfect cells, using cardiac-derived c-kit expressing cells as a model system
    Kalidasan V, Ng WH, Ishola OA, Ravichantar N, Tan JJ, Das KT
    Sci Rep, 2021 Sep 28;11(1):19265.
    PMID: 34584147 DOI: 10.1038/s41598-021-98657-7
    Gene therapy revolves around modifying genetic makeup by inserting foreign nucleic acids into targeted cells via gene delivery methods to treat a particular disease. While the genes targeted play a key role in gene therapy, the gene delivery system used is also of utmost importance as it determines the success of gene therapy. As primary cells and stem cells are often the target cells for gene therapy in clinical trials, the delivery system would need to be robust, and viral-based entries such as lentiviral vectors work best at transporting the transgene into the cells. However, even within lentiviral vectors, several parameters can affect the functionality of the delivery system. Using cardiac-derived c-kit expressing cells (CCs) as a model system, this study aims to optimize lentiviral production by investigating various experimental factors such as the generation of the lentiviral system, concentration method, and type of selection marker. Our findings showed that the 2nd generation system with pCMV-dR8.2 dvpr as the packaging plasmid produced a 7.3-fold higher yield of lentiviral production compared to psPAX2. Concentrating the virus with ultracentrifuge produced a higher viral titer at greater than 5 × 105 infectious unit values/ml (IFU/ml). And lastly, the minimum inhibitory concentration (MIC) of puromycin selection marker was 10 μg/mL and 7 μg/mL for HEK293T and CCs, demonstrating the suitability of antibiotic selection for all cell types. This encouraging data can be extrapolated and applied to other difficult-to-transfect cells, such as different types of stem cells or primary cells.
    Matched MeSH terms: Genetic Vectors/genetics*; Lentivirus/genetics*
  9. Fulltext Evaluation of two short tandem repeat multiplex systems for post-haematopoietic stem cell transplantation chimerism analysis
    Ariffin H, Daud SS, Mohamed Z, Ibrahim K, Lee TF, Chong LA
    Singapore Med J, 2007 Apr;48(4):333-7.
    PMID: 17384881
    The follow-up of chimerism status after allogeneic haematopoietic stem cell transplantation (HSCT) is essential to predict successful engraftment to assess the development of graft-versus-host disease, graft rejection and disease relapse. Analysis of short tandem repeats (STR) via polymerase chain reaction is frequently used for chimerism determination. However, most commercially-available kits have been designed for forensic purposes and may not be optimal for chimerism analysis. The present study aims to identify suitable STR markers for patient-donor pairs of predominantly Malay and Chinese ethnicity using two commercially-available forensic kits.
    Matched MeSH terms: Transplantation Chimera/genetics*; Asian Continental Ancestry Group/genetics
  10. Gene frequencies of human platelet alloantigens in Kelantan, Malaysia
    Bhaskar S, Abdullah JM, Yusoff NM, Prasad A
    Singapore Med J, 2007 Jun;48(6):598-9.
    PMID: 17538770
    Matched MeSH terms: Antigens, Human Platelet/genetics*; Oceanic Ancestry Group/genetics
  11. Fulltext Rapid detection and serotyping of dengue virus by multiplex RT-PCR and real-time SYBR green RT-PCR
    Yong YK, Thayan R, Chong HT, Tan CT, Sekaran SD
    Singapore Med J, 2007 Jul;48(7):662-8.
    PMID: 17609830
    Dengue fever and dengue haemorrhagic fever currently rank highly among the newly-emerging infectious diseases, and are considered to be the most important arboviral disease worldwide. The definitive diagnosis is culture analysis, but practical considerations limit its use. Also, the period for viral detection is limited. Within a day or two after fever subsides, rising levels of antibodies interfere with viral cultures. An alternative to this quandary is the use of viral RNA detection assays. In our laboratory, a reverse transcriptase polymerase chain reaction (RT-PCR) assay was developed using a set of degenerate primers.
    Matched MeSH terms: Dengue/genetics; Dengue Virus/genetics*
  12. Fulltext A Malay boy with the Cornelia de Lange syndrome: clinical and molecular findings
    Bhuiyan ZA, Zilfalil BA, Hennekam RC
    Singapore Med J, 2006 Aug;47(8):724-7.
    PMID: 16865217
    The Cornelia de Lange syndrome is a multiple congenital anomaly syndrome characterised by dysmorphic facial features, hirsutism, severe growth and developmental delays, and malformed upper limbs. The prevalence is estimated to be one per 10,000. Recently, several independent groups proved that Cornelia de Lange syndrome is caused by mutations in the NIPBL gene, the human homologue of the Drosophila Nipped-B gene. Here, we present the first clinical case report of a Malay child, a 9-year-old boy with the Cornelia de Lange syndrome. We also report the molecular investigation of the NIPBL gene in this patient.
    Matched MeSH terms: Abnormalities, Multiple/genetics; De Lange Syndrome/genetics
  13. Fulltext Chinese in west Malaysia: the geography of beta thalassaemia mutations
    George-Kodiseri E, Yang KG, Kutlar F, Wilson JB, Kutlar A, Stoming TA, et al.
    Singapore Med J, 1990 Aug;31(4):374-7.
    PMID: 2255937
    The overseas Chinese in West Malaysia are almost exclusively from the south-eastern provinces of China-Kwangtung, Fukien, and Kwangsi. To institute a comprehensive thalassaemia control programme for this region we have characterised the beta thalassaemia mutations in 16 Chinese patients from West Malaysia: 4 beta thalassaemia mutations were seen: a) an A----G substitution in the TATA box [-28 base pairs (bp)], an A----T substitution in codon 17 [17 A----T], c) a 4 base pairs - TCTT deletion in codon 41-42 [frameshift mutation (FSC 41-42)], and d) a C----T substitution at the second intervening sequence (IVS 11) position 654. Similar mutations have been described in patients from the south-eastern provinces of China. The delineation of the specific mutations present will enable effective prenatal diagnosis for beta thalassaemia of ethnic Chinese in West Malaysia to be instituted.
    Matched MeSH terms: Hemoglobin E/genetics; Immunogenetics; Thalassemia/genetics*
  14. Fulltext T-cell-replete haploidentical bone marrow transplantation for X-linked severe combined immunodeficiency
    Ariffin H, Chew KS, Jawin V, Thavagnanam S
    Singapore Med J, 2020 May;61(5):284-285.
    PMID: 30128577 DOI: 10.11622/smedj.2018101
    Matched MeSH terms: Interleukin Receptor Common gamma Subunit/genetics; X-Linked Combined Immunodeficiency Diseases/genetics
  15. Recent Developments and Challenges in Molecular-Targeted Therapy of Non-Small-Cell Lung Cancer
    Rohilla S, Singh M, Alzarea SI, Almalki WH, Al-Abbasi FA, Kazmi I, et al.
    J Environ Pathol Toxicol Oncol, 2023;42(1):27-50.
    PMID: 36734951 DOI: 10.1615/JEnvironPatholToxicolOncol.2022042983
    Treatment of lung cancer with conventional therapies, which include radiation, surgery, and chemotherapy results in multiple undesirable adverse or side effects. The major clinical challenge in developing new drug therapies for lung cancer is resistance, which involves mutations and disturbance in various signaling pathways. Molecular abnormalities related to epidermal growth factor receptor (EGFR), v-Raf murine sarcoma viral oncogene homolog B1 (B-RAF) Kirsten rat sarcoma virus (KRAS) mutations, translocation of the anaplastic lymphoma kinase (ALK) gene, mesenchymal-epithelial transition factor (MET) amplification have been studied to overcome the resistance and to develop new therapies for non-small cell lung cancer (NSCLC). But, inevitable development of resistance presents limits the clinical benefits of various new drugs. Here, we review current progress in the development of molecularly targeted therapies, concerning six clinical biomarkers: EGFR, ALK, MET, ROS-1, KRAS, and B-RAF for NSCLC treatment.
    Matched MeSH terms: Proto-Oncogene Proteins p21(ras)/genetics; ErbB Receptors/genetics
  16. Retarding breast tumor growth with nanoparticle-facilitated intravenous delivery of BRCA1 and BRCA2 tumor suppressor genes
    Ibnat N, Chowdhury EH
    Sci Rep, 2023 Jan 11;13(1):536.
    PMID: 36631481 DOI: 10.1038/s41598-022-25511-9
    Gene augmentation therapy entails replacement of the abnormal tumor suppressor genes in cancer cells. In this study, we performed gene augmentation for BRCA1/2 tumor suppressors in order to retard tumor development in breast cancer mouse model. We formulated inorganic carbonate apatite (CA) nanoparticles (NPs) to carry and deliver the purified BRCA1/2 gene- bearing plasmid DNA both in vitro and in vivo. The outcome of BRCA1/2 plasmid-loaded NPs delivery on cellular viability of three breast cancer cell lines such as MCF-7, MDA-MB-231 and 4T1 were evaluated by MTT assay. The result in MCF-7 cell line exhibited that transfection of BRCA 1/2 plasmids with CA NPs significantly reduced cancer cell growth in comparison to control group. Moreover, we noticed a likely pattern of cellular cytotoxicity in 4T1 murine cancer cell line. Following transfection with BRCA1 plasmid-loaded NPs, and Western blot analysis, a notable reduction in the phospho-MAPK protein of MAPK signaling pathway was detected, revealing reduced growth signal. Furthermore, in vivo study in 4T1 induced breast cancer mouse model showed that the tumor growth rate and final volume were decreased significantly in the mouse group treated intravenously with BRCA1 + NPs and BRCA2 + NPs formulations. Our results established that BRCA1/2 plasmids incorporated into CA NPs mitigated breast tumor growth, signifying their application in the therapy for breast cancer.
    Matched MeSH terms: BRCA1 Protein/genetics; BRCA2 Protein/genetics
  17. Fulltext Phosphorylation of interferon regulatory factor 9 (IRF9)
    Paul A, Ismail MN, Tang TH, Ng SK
    Mol Biol Rep, 2023 Apr;50(4):3909-3917.
    PMID: 36662450 DOI: 10.1007/s11033-023-08253-3
    BACKGROUND: IRF9 is a transcription factor that mediates the expression of interferon-stimulated genes (ISGs) through the Janus kinase-Signal transducer and activator of transcription (JAK-STAT) pathway. The JAK-STAT pathway is regulated through phosphorylation reactions, in which all components of the pathway are known to be phosphorylated except IRF9. The enigma surrounding IRF9 regulation by a phosphorylation event is intriguing. As IRF9 plays a major role in establishing an antiviral state in host cells, the topic of IRF9 regulation warrants deeper investigation.

    METHODS: Initially, total lysates of 2fTGH and U2A cells (transfected with recombinant IRF9) were filter-selected and concentrated using phosphoprotein enrichment assay. The phosphoprotein state of IRF9 was further confirmed using Phos-tag™ assay. All protein expression was determined using Western blotting. Tandem mass spectrometry was conducted on immunoprecipitated IRF9 to identify the phosphorylated amino acids. Finally, site-directed mutagenesis was performed and the effects of mutated IRF9 on relevant ISGs (i.e., USP18 and Mx1) was evaluated using qPCR.

    RESULTS: IRF9 is phosphorylated at S252 and S253 under IFNβ-induced condition and R242 under non-induced condition. Site-directed mutagenesis of S252 and S253 to either alanine or aspartic acid has a modest effect on the upregulation of USP18 gene-a negative regulator of type I interferon (IFN) response-but not Mx1 gene.

    CONCLUSION: Our preliminary study shows that IRF9 is phosphorylated and possibly regulates USP18 gene expression. However, further in vivo studies are needed to determine the significance of IRF9 phosphorylation.

    Matched MeSH terms: STAT2 Transcription Factor/genetics; Interferon-Stimulated Gene Factor 3, gamma Subunit/genetics
  18. Prevalence and Distribution of Major β-Thalassemia Mutations and HbE/β-Thalassemia Variant in Nepalese Ethnic Groups
    Lama R, Yusof W, Shrestha TR, Hanafi S, Bhattarai M, Hassan R, et al.
    Hematol Oncol Stem Cell Ther, 2022 Mar 01;15(1):279-284.
    PMID: 33592169 DOI: 10.1016/j.hemonc.2021.01.004
    BACKGROUND: Beta-thalassemia is a genetic disorder that is inherited in an autosomal recessive pattern. This genetic disease leads to a defective beta-globin hemoglobin chain causing partial or complete beta-globin chain synthesis loss. Beta-thalassemia major patients need a continuous blood transfusion and iron chelation to maintain the normal homeostasis of red blood cells (RBCs) and other systems in the body. Patients also require treatment procedures that are costly and tedious, resulting in a serious health burden for developing nations such as Nepal.

    METHODS: A total of 61 individuals clinically diagnosed to have thalassemia were genotyped with multiplex amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). Twenty-one major mutations were investigated using allele-specific primers grouped into six different panels.

    RESULTS: The most common mutations found (23%) were IVS 1-5 (G-C) and Cd 26 (G-A) (HbE), followed by 619 deletion, Cd 8/9 (+G), Cd 16 (-C), Cd 41/42 (-TTCT), IVS 1-1 (G-T), Cd 19 (A-G), and Cd 17 (A-T) at 20%, 12%, 8%, 6%, 4%, 3%, and 1%, respectively.

    CONCLUSION: The results of this study revealed that Nepal's mutational profile is comparable to that of its neighboring countries, such as India and Myanmar. This study also showed that thalassemia could be detected across 17 Nepal's ethnic groups, especially those whose ancestors originated from India and Central Asia.

    Matched MeSH terms: Ethnic Groups/genetics; beta-Globins/genetics
  19. Fulltext Clinical, immunological, molecular and therapeutic findings in monogenic immune dysregulation diseases: Middle East and North Africa registry
    Jamee M, Azizi G, Baris S, Karakoc-Aydiner E, Ozen A, Kiliç SŞ, et al.
    Clin Immunol, 2022 Nov;244:109131.
    PMID: 36179983 DOI: 10.1016/j.clim.2022.109131
    Monogenic immune dysregulation diseases (MIDD) are caused by defective immunotolerance. This study was designed to increase knowledge on the prevalence and spectrum of MIDDs, genetic patterns, and outcomes in Middle East and North Africa (MENA). MIDD patients from 11 MENA countries (Iran, Turkey, Kuwait, Oman, Algeria, Egypt, United Arab Emirates, Tunisia, Jordan, Qatar, and Azerbaijan) were retrospectively evaluated. 343 MIDD patients (58% males and 42% female) at a median (IQR) age of 101 (42-192) months were enrolled. The most common defective genes were LRBA (23.9%), LYST (8.2%), and RAB27A (7.9%). The most prevalent initial and overall manifestations were infections (32.2% and 75.1%), autoimmunity (18.6% and 41%), and organomegaly (13.3% and 53.8%), respectively. Treatments included immunoglobulin replacement therapy (53%), hematopoietic stem cell transplantation (HSCT) (14.3%), immunosuppressives (36.7%), and surgery (3.5%). Twenty-nine (59.2%) patients survived HSCT. Along with infectious complications, autoimmunity and organomegaly may be the initial or predominant manifestations of MIDD.
    Matched MeSH terms: Vesicular Transport Proteins/genetics; Adaptor Proteins, Signal Transducing/genetics
  20. Fulltext Colorimetric detection of SARS-CoV-2 by uracil-DNA glycosylase (UDG) reverse transcription loop-mediated isothermal amplification (RT-LAMP)
    Lai MY, Bukhari FDM, Zulkefli NZ, Ismail I, Mustapa NI, Soh TST, et al.
    Int J Infect Dis, 2022 Jul;120:132-134.
    PMID: 35472524 DOI: 10.1016/j.ijid.2022.04.036
    OBJECTIVES: Preventing reverse transcription loop-mediated isothermal amplification (RT-LAMP) carryover contamination could be solved by adding deoxyuridine triphosphate (dUTP) and uracil-DNA glycosylase (UDG) into the reaction master mix.

    METHODS: RNA was extracted from nasopharyngeal swab samples by a simple RNA extraction method.

    RESULTS: Testing of 77 samples demonstrated 91.2% sensitivity (95% confidence interval [CI]: 78-98.2%) and 100% specificity (95% confidence interval: 92-100%) using UDG RT-LAMP.

    CONCLUSION: This colorimetric UDG RT-LAMP is a simple-to-use, fast, and easy-to-interpret method, which could serve as an alternative for diagnosis of SARS-CoV-2 infection, especially in remote hospitals and laboratories with under-equipped medical facilities.

    Matched MeSH terms: RNA, Viral/genetics; Uracil-DNA Glycosidase/genetics
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