Displaying publications 1 - 20 of 26 in total

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  1. Fulltext The co-existence of pure red cell aplasia and autoimmune haemolytic anaemia in a child with malignant lymphoma
    Ahmed SA, Hassan R
    Malays J Med Sci, 2005 Jul;12(2):56-9.
    PMID: 22605959 MyJurnal
    The association between pure red cell aplasia (PRCA) and autoimmune haemolytic anaemia (AIHA) has rarely been reported. PRCA represents an isolated process, characterized by normochromic, normocytic anaemia, reticulocytopenia and erythroid hypoplasia in the bone marrow, and may be attributable to infection with Parvo virus B19. AIHA is a condition in which peripheral red blood cell destruction is induced by the presence of autoantibodies. However, the co-existence of these conditions is very rare, since only few cases of PRCA and AIHA associated with malignant lymphoma (ML) were reported. A case of PRCA and AIHA was detected and described, for the first time in Malaysia, in a 10-year-old child suffering from non-Hodgkin lymphoma from the Department of Haematology, Universiti Sains Malaysia. Following the induction course of chemotherapy, the patient turned anaemic, with tendency for red cell clumping, reticulocytopenia and anisocytosis. AIHA was suspected in spite of the weak Coomb reaction obtained. The bone marrow aspirate revealed the presence of giant pronormoblasts, suggesting PRCA. Serological tests for Parvo virus and other viruses were negative.
  2. Transcription start site mapping and small RNA profiling of Leptospira biflexa serovar Patoc
    Cheah HL, Ahmed SA, Tang TH
    World J Microbiol Biotechnol, 2023 Feb 21;39(4):104.
    PMID: 36808011 DOI: 10.1007/s11274-023-03540-4
    Leptospirosis is an emerging zoonotic disease caused by bacterial species of the genus Leptospira. However, the regulatory mechanisms and pathways underlying the adaptation of pathogenic and non-pathogenic Leptospira spp. in different environmental conditions remain elusive. Leptospira biflexa is a non-pathogenic species of Leptospira that lives exclusively in a natural environment. It is an ideal model not only for exploring molecular mechanisms underlying the environmental survival of Leptospira species but also for identifying virulence factors unique to Leptospira's pathogenic species. In this study, we aim to establish the transcription start site (TSS) landscape and the small RNA (sRNA) profile of L. biflexa serovar Patoc grown to exponential and stationary phases via differential RNA-seq (dRNA-seq) and small RNA-seq (sRNA-seq) analyses, respectively. Our dRNA-seq analysis uncovered a total of 2726 TSSs, which are also used to identify other elements, e.g., promoter and untranslated regions (UTRs). Besides, our sRNA-seq analysis revealed a total of 603 sRNA candidates, comprising 16 promoter-associated sRNAs, 184 5'UTR-derived sRNAs, 230 true intergenic sRNAs, 136 5'UTR-antisense sRNAs, and 130 open reading frame (ORF)-antisense sRNAs. In summary, these findings reflect the transcriptional complexity of L. biflexa serovar Patoc under different growth conditions and help to facilitate our understanding of regulatory networks in L. biflexa. To the best of our knowledge, this is the first study reporting the TSS landscape of L. biflexa. The TSS and sRNA landscapes of L. biflexa can also be compared with its pathogenic counterparts, e.g., L. borgpetersenii and L. interrogans, to identify features contributing to their environmental survival and virulence.
  3. Fulltext Identification of hemoglobin AC heterozygote status in a Malay family: a decision between hemoglobin electrophoresis and high performance liquid chromotography
    Rosline H, Roshan TM, Ahmed SA, Ilunihayati I
    Southeast Asian J Trop Med Public Health, 2007 May;38(3):543-5.
    PMID: 17877232
    Thalassemia is a common public health problem among Malays. Hemoglobin C (Hb C) is a hemoglobin beta variant resulting from a single base mutation at the 6th position of the beta-globin gene leading to the substitution of glycine for glutamic acid. Hb C is commonly detected in West Africans and in African American but has not been reported in Malaysia. It can be falsely diagnosed as HbE trait in the Malaysian Thalassemia Screening Program which utilizes cellulose acetate hemoglobin electrophoresis. This is the first reported case of Hb AC heterozygote status in a Malay family, with unusual splenomegaly in one of the family members.
  4. Evaluation of serological transfusion-transmitted viral diseases and mutliplex nucleic acid testing in malaysian blood donors
    Yaseen SG, Ahmed SA, Johan MF, Kiron R, Daher AM
    Transfus Apher Sci, 2013 Dec;49(3):647-51.
    PMID: 23890575 DOI: 10.1016/j.transci.2013.07.003
    Transmission of infectious diseases is a recognized complication of blood transfusion and blood products. Nucleic acid testing (NAT) may contribute to improved efficiency of blood screening and thereby increase the safety margin for transfused blood.
  5. Rapid detection of Mycobacterium tuberculosis in clinical samples by multiplex polymerase chain reaction (mPCR)
    Tang TH, Ahmed SA, Musa M, Zainuddin ZF
    World J Microbiol Biotechnol, 2013 Dec;29(12):2389-95.
    PMID: 23807412 DOI: 10.1007/s11274-013-1407-0
    Although the multi-copy and specific element IS6110 provides a good target for the detection of Mycobacterium tuberculosis complex by PCR techniques, the emergence of IS6110-negative strains suggested that false negative may occur if IS6110 alone is used as the target for detection. In this report, a multiplex polymerase chain reaction (mPCR) system was developed using primers derived from the insertion sequence IS6110 and an IS-like elements designated as B9 (GenBank accession no. U78639.1) to overcome the problem of detecting negative or low copy IS6110 containing strains of M. tuberculosis. The mPCR was evaluated using 346 clinical samples which included 283 sputum, 19 bronchial wash, 18 pleural fluid, 9 urine, 7 CSF, 6 pus, and 4 gastric lavage samples. Our results showed that the sensitivity (93.1 %) and specificity (89.6 %) of the mPCR system exceeds that of the conventional method of microscopy and culture. The mPCR assay provides an efficient strategy to detect and identify M. tuberculosis from clinical samples and enables prompt diagnosis when rapid identification of infecting mycobacteria is necessary.
  6. Fulltext Formulation of nanoemulsion carriers containing Pennyroyal (Mentha pulegium) and Gijavash (Froriepia subpinnata) essential oils for enriching Doogh (Iranian dairy drink)
    Habibvand M, Yousefi M, Ahmed SA, Hassanzadeh H
    IET Nanobiotechnol, 2023 Apr;17(2):80-90.
    PMID: 36478175 DOI: 10.1049/nbt2.12106
    Today, the increasing use of chemical preservatives in foods is considered one of the main problems in food industries. This study aimed to produce the pasteurised Doogh (Iranian yogurt drink) containing a nanoemulsion of essential oil (EO) with appropriate quality. A factorial test based on a completely randomised design with two treatments in three levels, including EO type (pennyroyal, Gijavash, and their equal combination) and a control sample was applied to assess the physicochemical and sensory properties of Doogh. The highest negative zeta potential and antioxidant activity percentage were observed in the sample containing the nanoemulsion of pennyroyal and enriched with a combination of two essential oils. The microbial evaluation results indicated that the total microorganism count was minimised in the Doogh containing the nanoemulsion of Gijavash. The nanoemulsions of pennyroyal and Gijavash can be added into Doogh formulation to produce a new product with maximum sensory acceptability.
  7. Response rate of Malaysian blood donors with reactive screening test to transfusion medicine unit calls
    Roshan TM, Rosline H, Ahmed SA, Rapiaah M, Khattak MN
    Southeast Asian J Trop Med Public Health, 2009 Nov;40(6):1315-21.
    PMID: 20578467
    Blood donors with reactive screening test results are requested to come in for counseling by letter and telephone call. It has been noticed many donors responded to neither the letters nor the telephone calls. We evaluated 589 cases with reactive screening test results (208 positive for hepatitis C, 209 for hepatitis B, 85 for VDRL and 87 for HIV). In the hepatitis C positive group 61 donors (29.3%) did not respond and 4.7% missed their follow-up appointment. Similarly low response rates were noted with the HBV (58.9%) and VDRL (67.1%) positive groups. Among HIV positive donors 46.0% failed to respond to multiple calls. We conclude that blood donors in Malaysia have a poor response to calls from the blood transfusion unit. A review of the effectiveness of the current deferral system and an increased public knowledge of transmissible infectious diseases may encourage blood donors to have a better response rate.
  8. Blood pre-donation deferrals--a teaching hospital experience
    Rabeya Y, Rapiaah M, Rosline H, Ahmed SA, Zaidah WA, Roshan TM
    Southeast Asian J Trop Med Public Health, 2008 May;39(3):571-4.
    PMID: 18564700
    Blood donor selection contributes to the safety of both the donor and the recipient. The objective of this study was to identify the number and causes of blood pre-donation deferrals at the Hospital Universiti Sains Malaysia (HUSM). A retrospective study was carried out to retrieve data regarding deferred blood donors at the HUSM in the year 2006. A total of 4,138 blood donors donated blood at the Transfusion Medicine Unit, of whom 231 were deferred or rejected as donors. The percentage of deferred donors was 5.6%. The main reason for deferral was a low hemoglobin (40.7%), with females constituting the majority of those deferred. This was followed by high blood pressure (29.4%) and male donors were predominant in this group. Medical illness caused 15.6% of donor deferrals. The majority of deferred donors were regular donors (64.1%). We recommend setting new hemoglobin criteria for donor deferral according to the reference range obtained for the particular population. Most of the other deferrals were preventable by proper health care education and awareness.
  9. Trends in hepatitis B virus infection among blood donors in Kelantan, Malaysia: a retrospective study
    Yousuf R, Rapiaah M, Ahmed SA, Rosline H, Salam A, Selamah S, et al.
    Southeast Asian J Trop Med Public Health, 2007 Nov;38(6):1070-4.
    PMID: 18613548
    The objective of this study was to determine the prevalence and trends in hepatitis B infection among blood donors attending the Transfusion Medicine Unit at the Hospital Universiti Sains Malaysia, Kelantan, Malaysia. A retrospective study was carried out by reviewing the results of HBsAg among blood donors for the years 2000 to 2004. During this period, 44,658 blood donors were studied. We noted that there was a significant difference in the prevalence of hepatitis B infection between regular and first time donors. There was also a decreasing trend noticed in both study groups. The mean prevalence was significantly different between first time (1.83%) and regular donors (0.45%) (p < 0.005). There is a need to improve public awareness programs to lower the incidence of hepatitis B infection in the general population and consequently first time blood donors. Future studies are also required to determine the trends and outcomes of these programs.
  10. Fulltext Testing for hepatitis B virus core antigen and e antigen may confer additional safety of donors' blood negative for heptitis B virus surface antigen
    Al-Joudi FS, Arif MB, Mohamed ZB, Ishak I, Ahmed SA
    Asian J Transfus Sci, 2014 Jan;8(1):63-4.
    PMID: 24678181 DOI: 10.4103/0973-6247.126700
  11. Fulltext Thrombotic thrombocytopenic purpura: three peripartum cases and diagnostic challenges
    Ab Rahman WS, Abdullah WZ, Mustaffa R, Ahmed SA, Hassan MN, Husin A
    Clin Med Insights Case Rep, 2013;6:141-6.
    PMID: 24093001 DOI: 10.4137/CCRep.S12122
    Thrombotic thrombocytopenic purpura (TTP) is a medical emergency characterized by occlusive microangiopathy due to intravascular platelet aggregation. This event results in damage to the red blood cells (RBCs) known as microangiopathic hemolytic anemia (MAHA). Schistocytes are circulating fragments of damaged RBCs that have different morphological features including keratocytes, helmet cells, and spherocytes. It is critical to report even a small number of these abnormal RBCs in the peripheral blood and to be alert for the possible diagnosis of TTP, especially in unexplained anemia and thrombocytopenia. The application of pentad criteria in the diagnosis has been reviewed, and the challenges still remained on the hematologic evidence of this disorder. In the 3 cases discussed here, the red cell morphological diagnosis gave an impact on TTP diagnosis, but overdiagnosis might be encountered in obstetrical patients due to nonspecific diagnostic criteria.
  12. Fulltext Red cell phenotyping of blood from donors at the National blood center of Malaysia
    Musa RH, Ahmed SA, Hashim H, Ayob Y, Asidin NH, Choo PY, et al.
    Asian J Transfus Sci, 2012 Jan;6(1):3-9.
    PMID: 22623834 DOI: 10.4103/0973-6247.95042
    Human blood groups are polymorphic and inherited integral structures of the red cell membrane. More than 300 red cell antigens have been identified and further categorized into 30 major discrete systems. Their distribution varies in different communities and ethnic groups.
  13. Hematological reference values of healthy Malaysian population
    Roshan TM, Rosline H, Ahmed SA, Rapiaah M, Wan Zaidah A, Khattak MN
    Int J Lab Hematol, 2009 Oct;31(5):505-12.
    PMID: 18498389 DOI: 10.1111/j.1751-553X.2008.01068.x
    Health and disease can only be distinguished by accurate and reliable reference values of a particular laboratory test. It is now a proven fact that there is considerable variation in hematology reference intervals depending on the demographic and preanalytical variables. There are evidences that values provided by manufacturers do not have appropriate application for all populations. Moreover, reference ranges provided by different laboratory manuals and books also do not solve this problem. We are presenting here normal reference ranges of Malaysian population. These values were determined by using Sysmex XE-2100 and ACL 9000 hematology and coagulation analyzers. Results from this study showed that there were considerable differences in the reference values from manufacturers, western population or laboratory manuals compared with those from the local population.
  14. Bacterial regulatory RNAs: complexity, function, and putative drug targeting
    Cheah HL, Raabe CA, Lee LP, Rozhdestvensky TS, Citartan M, Ahmed SA, et al.
    Crit Rev Biochem Mol Biol, 2018 08;53(4):335-355.
    PMID: 29793351 DOI: 10.1080/10409238.2018.1473330
    Over the past decade, RNA-deep sequencing has uncovered copious non-protein coding RNAs (npcRNAs) in bacteria. Many of them are key players in the regulation of gene expression, taking part in various regulatory circuits, such as metabolic responses to different environmental stresses, virulence, antibiotic resistance, and host-pathogen interactions. This has contributed to the high adaptability of bacteria to changing or even hostile environments. Their mechanisms include the regulation of transcriptional termination, modulation of translation, and alteration of messenger RNA (mRNA) stability, as well as protein sequestration. Here, the mechanisms of gene expression by regulatory bacterial npcRNAs are comprehensively reviewed and supplemented with well-characterized examples. This class of molecules and their mechanisms of action might be useful targets for the development of novel antibiotics.
  15. Rapid detection of porcine DNA in processed food samples using a streamlined DNA extraction method combined with the SYBR Green real-time PCR assay
    Tan LL, Ahmed SA, Ng SK, Citartan M, Raabe CA, Rozhdestvensky TS, et al.
    Food Chem, 2020 Mar 30;309:125654.
    PMID: 31678669 DOI: 10.1016/j.foodchem.2019.125654
    A specialized DNA extraction method and a SYBR Green quantitative polymerase chain reaction (SyG-qPCR) assay were combined to generate a ready-to-use kit for rapid detection of porcine admixtures in processed meat products. Our qPCR assay utilized repetitive LINE-1 elements specific to the genome of Sus scrofa domesticus (pig) as a target and incorporated internal controls. We improved the genomic DNA extraction method, and reduced extraction times to the minimum. The method was validated for specificity, sensitivity (0.001% w/w) and robustness, and values were compared with those of a commercially available kit. We also tested our method using 121 processed food products and consistently detected amplification only in samples containing pork. Due to its efficiency and cost-effectiveness, our method represents a valuable new method for detecting food adulteration with pork that is superior to existing quality control approaches.
  16. Antiproliferative and cell cycle arrest potentials of 3-O-acetyl-11-keto-β-boswellic acid against MCF-7 cells in vitro
    Ahmed SA, Al-Shanon AF, Al-Saffar AZ, Tawang A, Al-Obaidi JR
    J Genet Eng Biotechnol, 2023 Jul 02;21(1):75.
    PMID: 37393563 DOI: 10.1186/s43141-023-00529-2
    INTRODUCTION: Cancer is a major issue in medical science with increasing death cases every year worldwide. Therefore, searching for alternatives and nonorthodox methods of treatments with high efficiency, selectivity and less toxicity is the main goal in fighting cancer. Acetyl-11-keto-β-boswellic acid (AKBA), is a derivative pentacyclic triterpenoid that exhibited various biological activities with potential anti-tumoral agents. In this research, AKBA was utilized to examine the potential cytotoxic activity against MCF-7 cells in vitro and monitor the cellular and morphological changes with a prospective impact on apoptosis induction.

    METHODS: The cytotoxic activity of AKBA was measured by 3(4,5dimethylthiazole- 2-yl)-2,5 diphyneltetrazolium bromide (MTT) assay. A dose-dependent inhibition in MCF-7 cell viability was detected. The clonogenicity of MCF-7 cells was significantly suppressed by AKBA increment in comparison with untreated cells.

    RESULT: Morphologically, exposure of MCF-7 cells to high AKBA concentrations caused changes in cell nuclear morphology which was indicated by increasing in nuclear size and cell permeability intensity. The mitochondrial membrane potential (ΔΨm) was reduced by increasing AKBA concentration with a significant release of cytochrome c. Acridine orange/ethidium bromide dual staining experiment confirmed that MCF-7 cells treated with AKBA (IC50 concentration) displayed a late stage of apoptosis indicated by intense and bright reddish colour.

    CONCLUSION: A significant increase in reactive oxygen species formation was observed. Caspase 8 and caspase 9 activities were estimated and AKBA activated the production of caspase 8 and caspase 9 in a dose-dependent pattern. Finally, the cell phase distribution analysis was conducted, and flow cytometric analysis showed that AKBA at 200 μg mL-1 significantly arrest MCF-7 cells at the G1 phase and triggered apoptosis.

  17. Fulltext Biocomputational Identification of sRNAs in Leptospira interrogans Serovar Lai
    Tan XY, Citartan M, Chinni SV, Ahmed SA, Tang TH
    Indian J Microbiol, 2023 Mar;63(1):33-41.
    PMID: 37188232 DOI: 10.1007/s12088-022-01050-9
    Regulatory small RNAs (sRNA) are RNA transcripts that are not translated into proteins but act as functional RNAs. Pathogenic Leptospira cause an epidemic spirochaetal zoonosis, Leptospirosis. It is speculated that Leptospiral sRNAs are involved in orchestrating their pathogenicity. In this study, biocomputational approach was adopted to identify Leptospiral sRNAs. In this study, two sRNA prediction programs, i.e., RNAz and nocoRNAc, were employed to screen the reference genome of Leptospira interrogans serovar Lai. Out of 126 predicted sRNAs, there are 96 cis-antisense sRNAs, 28 trans-encoded sRNAs and 2 sRNAs that partially overlap with protein-coding genes in a sense orientation. To determine whether these candidates are expressed in the pathogen, they were compared with the coverage files generated from our RNA-seq datasets. It was found out that 7 predicted sRNAs are expressed in mid-log phase, stationary phase, serum stress, temperature stress and iron stress while 2 sRNAs are expressed in mid-log phase, stationary phase, serum stress, and temperature stress. Besides, their expressions were also confirmed experimentally via RT-PCR. These experimentally validated candidates were also subjected to mRNA target prediction using TargetRNA2. Taken together, our study demonstrated that biocomputational strategy can serve as an alternative or as a complementary strategy to the laborious and expensive deep sequencing methods not only to uncover putative sRNAs but also to predict their targets in bacteria. In fact, this is the first study that integrates computational approach to predict putative sRNAs in L. interrogans serovar Lai.

    SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12088-022-01050-9.

  18. Fulltext Utilization of Small RNA Genes to Distinguish Vibrio cholerae Biotypes via Multiplex Polymerase Chain Reaction
    Ahmed SA, Raabe CA, Cheah HL, Hoe CH, Rozhdestvensky TS, Tang TH
    Am J Trop Med Hyg, 2019 Jun;100(6):1328-1334.
    PMID: 30963989 DOI: 10.4269/ajtmh.18-0525
    The diarrheal disease "cholera" is caused by Vibrio cholerae, and is primarily confined to endemic regions, mostly in Africa and Asia. It is punctuated by outbreaks and creates severe challenges to public health. The disease-causing strains are most-often members of serogroups O1 and O139. PCR-based methods allow rapid diagnosis of these pathogens, including the identification of their biotypes. However, this necessitates the selection of specific target sequences to differentiate even the closely related biotypes of V. cholerae. Oligonucleotides for selective amplification of small RNA (sRNA) genes that are specific to these V. cholerae subtypes were designed. The resulting multiplex PCR assay was validated using V. cholerae cultures (i.e., 19 V. cholerae and 22 non-V. cholerae isolates) and spiked stool samples. The validation using V. cholerae cultures and spiked stool suspensions revealed detection limits of 10-100 pg DNA per reaction and 1.5 cells/mL suspension, respectively. The multiplex PCR assay that targets sRNA genes for amplification enables the sensitive and specific detection, as well as the differentiation of V. cholerae-O1 classical, O1 El Tor, and O139 biotypes. Most importantly, the assay enables fast and cheaper diagnosis compared with classic culture-based methods.
  19. Fulltext Rapid diagnosis of leptospirosis by multiplex PCR
    Ahmed SA, Sandai DA, Musa S, Hoe CH, Riadzi M, Lau KL, et al.
    Malays J Med Sci, 2012 Jul;19(3):9-16.
    PMID: 23610544 MyJurnal
    Traditionally, the most common diagnostic approach used for diagnosing leptospirosis was the demonstration of immune-seroconversion in acute and convalescent patient serum samples. Recently, a variety of molecular techniques, including conventional and real-time polymerase chain reaction (PCR), have been developed for the specific detection of pathogenic bacteria from the genus Leptospira. PCR is a sensitive, specific, and rapid technique that has been successfully used to detect several microorganisms; including those of clinical significance.
  20. The prevalence of human cytomegalovirus seropositivity among blood donors at the Unit of Blood Transfusion Medicine, Hospital Universiti Sains Malaysia
    Ahmed SA, Al-Joudi FS, Zaidah AW, Roshan TM, Rapiaah M, Abdullah YM, et al.
    Southeast Asian J Trop Med Public Health, 2006 Mar;37(2):294-6.
    PMID: 17124989
    Human cytomegalovirus (HCMV) is a species-specific DNA virus of the Herpetoviridae family. After a primary infection, HCMV persists in a latent form most probably in bone marrow progenitor cells or in peripheral blood monocytes. The virus can reactivate to result in shedding of the virus leading to virus dissemination and new infections. Immunocompromized patients are the ones most vulnerable to serious diseases occasionally acquired in blood transfusions. In a human population, HCMV seropositivity increases steadily with age to become approximately 100% in adults. This study was performed to detect seropositivity among regular blood donors in The Hospital of the Universiti Sains Malaysia, in the state of Kelantan. Using an enzyme immunoassay, it was found that 97.6% of blood donors were HCMV-positive. HCMV is highly prevalent and may be endemic in Kelantan. Hence, long-term strategies are required for the reduction of disease dissemination, and to prevent the exposure of immunocompromized patients to the virus.
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