Displaying publications 21 - 40 of 441 in total

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  1. Hirayama K, Zaidi AS, Lokman Hakim S, Kimura A, Ong KJ, Kikuchi M, et al.
    Tissue Antigens, 1996 Dec;48(6):692-7.
    PMID: 9008312
    We have examined 56 unrelated individuals from Malaysian aborigines for their DNA polymorphism of the HLA-B gene by sequence specific oligonucleotide probe (SSO) method. Using the SSO hybridization, we found that one specific DNA allele with a B*1513 like pattern of epitope combination (ECB1513) was dominant among the Melayu Asli (Af = 41.9%) and the Senoi (Af = 24%). To determine the nucleotide sequences of ECB1513, a DNA fragment spanning from the beginning of exon 1 to the middle of exon 4 of the HLA-B gene was amplified by polymerase chain reaction (PCR) from two ECB1513 positive individuals, and the PCR products were cloned and sequenced. This sequencing analysis confirmed that ECB1513 was identical to HLA-B*1513 in exon 1, 2, 3, and 4. Amino acid sequence of this major allele, HLA-B*1513, in the aborigines especially around the peptide binding groove (B and F pockets), was compared with that of African B*5301 that had been suggested to confer resistance to malaria infection in Africa. The amino acid residues composing of the F pocket were completely identical in B*1513 and B*5301. These observations suggest that a common environmental factor, the malaria infection, might have independently enhanced the selection of functional change in the polymorphic portion of HLA-B gene in Africa and in South-East Asia.
    Matched MeSH terms: Polymorphism, Genetic
  2. Amin AM, Sheau Chin L, Mohamed Noor DA, Mostafa H, Abdul Kader MASK, Kah Hay Y, et al.
    Thromb Res, 2017 10;158:22-24.
    PMID: 28802144 DOI: 10.1016/j.thromres.2017.07.032
    Matched MeSH terms: Polymorphism, Genetic
  3. Teh LK, Hamzah S, Hashim H, Bannur Z, Zakaria ZA, Hasbullani Z, et al.
    Ther Drug Monit, 2013 Oct;35(5):624-30.
    PMID: 23942539 DOI: 10.1097/FTD.0b013e318290acd2
    Dihydropyrimidine dehydrogenase (DPD) is a pyrimidine catabolic enzyme involved in the initial and rate-limiting step of the catabolic pathway of toxic metabolites of 5-fluorouracil (5-FU). Several studies have reported that deficiency of DPD and polymorphisms of its gene are related to 5-FU toxicities and death. Association between serum concentration of 5-FU and its related toxicity has also been previously demonstrated. Hence, this study aims to understand the role of DPYD variants in serum level of 5-FU and the risk of developing toxicity to prevent adverse reactions and maximize therapy outcome for personalized medicine.
    Matched MeSH terms: Polymorphism, Genetic/genetics
  4. Yeap LL, Lim KS, Ng CC, Hui-Ping Khor A, Lo YL
    Ther Drug Monit, 2014 Feb;36(1):3-9.
    PMID: 24342894 DOI: 10.1097/FTD.0000000000000024
    The authors describe a case of a 37-year-old Malay lady with an unusually slow carbamazepine clearance, which may be related to genetic polymorphisms of drug metabolizing enzymes and transporters. When given a small daily dose of 200 mg immediate-release carbamazepine, this patient experienced drowsiness. Subsequently, she reduced her carbamazepine dose to 200 mg twice a week (on Mondays and Fridays), resulting in poor seizure control. At the same time, the patient was diagnosed with hyperthyroidism and was given carbimazole and propranolol. Hyperthyroidism and the concurrent use of these antihyperthyroid agents may have further slowed down the metabolism of carbamazepine. Therapeutic drug monitoring of carbamazepine was carried out, and a slow carbamazepine clearance of 1.45 L·h⁻¹ per 70 kg was observed. Genotyping of selected genetic variants in CYP3A4, CYP3A5, EPHX1, ABCB1, and ABCC2 revealed that she has CYP3A5*3/*3 and ABCB1 3435-CC genotypes. Both genotypes have been shown to be associated with higher adjusted mean serum carbamazepine concentration in Chinese and Korean patients with epilepsy. Physicians should be vigilant about the risk of adverse effects among patients with a slow carbamazepine clearance, especially in Malays. Simulations of carbamazepine dosing regimen based on the pharmacokinetic parameters of this patient were performed to allow individualization of drug therapy.
    Matched MeSH terms: Polymorphism, Genetic
  5. Latif MA, Rafii MY, Mazid MS, Ali ME, Ahmed F, Omar MY, et al.
    ScientificWorldJournal, 2012;2012:586831.
    PMID: 22593700 DOI: 10.1100/2012/586831
    Direct amplified length polymorphism (DALP) combines the advantages of a high-resolution fingerprint method and also characterizing the genetic polymorphisms. This molecular method was also found to be useful in brown planthopper, Nilaparvata lugens species complex for the analysis of genetic polymorphisms. A total of 11 populations of Nilaparvata spp. were collected from 6 locations from Malaysia. Two sympatric populations of brown planthopper, N. lugens, one from rice and the other from a weed grass (Leersia hexandra), were collected from each of five locations. N. bakeri was used as an out group. Three oligonucleotide primer pairs, DALP231/DALPR'5, DALP234/DALPR'5, and DALP235/DALPR'5 were applied in this study. The unweighted pair group method with arithmetic mean (UPGMA) dendrogram based on genetic distances for the 11 populations of Nilaparvata spp. revealed that populations belonging to the same species and the same host type clustered together irrespective of their geographical localities of capture. The populations of N. lugens formed into two distinct clusters, one was insects with high esterase activities usually captured from rice and the other was with low esterase activities usually captured from L. hexandra. N. bakeri, an out group, was the most isolated group. Analyses of principal components, molecular variance, and robustness also supported greatly to the findings of cluster analysis.
    Matched MeSH terms: Polymorphism, Genetic
  6. Chan SL, Suo C, Lee SC, Goh BC, Chia KS, Teo YY
    Pharmacogenomics J, 2012 Aug;12(4):312-8.
    PMID: 21383771 DOI: 10.1038/tpj.2011.7
    Genetic markers displaying highly significant statistical associations with complex phenotypes may not necessarily possess sufficient clinical validity to be useful. Understanding the contribution of these markers beyond readily available clinical biomarkers is particularly important in pharmacogenetics. We demonstrate the utility of genetic testing using the example of warfarin in a multi-ethnic setting comprising of three Asian populations that are broadly representative of the genetic diversity for half of the population in the world, especially as distinct interethnic differences in warfarin dose requirements have been previously established. We confirmed the roles of three well-established loci (CYP2C9, VKORC1 and CYP4F2) in explaining warfarin dosage variation in the three Asian populations. In addition, we assessed the relationship between ethnicity and the genotypes of these loci, observing strong correlations at VKORC1 and CYP4F2. Subsequently, we established the additional utility of these genetic factors in predicting warfarin dose beyond ethnicity and clinical biomarkers through performing a series of systematic cross-validation analyses of the relative predictive accuracies of various fixed-dose regimen, clinical and genetic models. Through a pharmacogenetics model for warfarin, we show the importance of genetic testing beyond readily available clinical biomarkers in predicting dose requirements, confirming the role of genetic profiling in personalized medicine.
    Matched MeSH terms: Polymorphism, Genetic
  7. Hor SY, Lee SC, Wong CI, Lim YW, Lim RC, Wang LZ, et al.
    Pharmacogenomics J, 2008 Apr;8(2):139-46.
    PMID: 17876342
    Previously studied candidate genes have failed to account for inter-individual variability of docetaxel and doxorubicin disposition and effects. We genotyped the transcriptional regulators of CYP3A and ABCB1 in 101 breast cancer patients from 3 Asian ethnic groups, that is, Chinese, Malays and Indians, in correlation with the pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin. While there was no ethnic difference in docetaxel and doxorubicin pharmacokinetics, ethnic difference in docetaxel- (ANOVA, P=0.001) and doxorubicin-induced (ANOVA, P=0.003) leukocyte suppression was observed, with Chinese and Indians experiencing greater degree of docetaxel-induced myelosuppression than Malays (Bonferroni, P=0.002, P=0.042), and Chinese experiencing greater degree of doxorubicin-induced myelosuppression than Malays and Indians (post hoc Bonferroni, P=0.024 and 0.025). Genotyping revealed both PXR and CAR to be well conserved; only a PXR 5'-untranslated region polymorphism (-24381A>C) and a silent CAR variant (Pro180Pro) were found at allele frequencies of 26 and 53%, respectively. Two non-synonymous variants were identified in HNF4alpha (Met49Val and Thr130Ile) at allele frequencies of 55 and 1%, respectively, with the Met49Val variant associated with slower neutrophil recovery in docetaxel-treated patients (ANOVA, P=0.046). Interactions were observed between HNF4alpha Met49Val and CAR Pro180Pro, with patients who were wild type for both variants experiencing least docetaxel-induced neutropenia (ANOVA, P=0.030). No other significant genotypic associations with pharmacokinetics or pharmacodynamics of either drug were found. The PXR-24381A>C variants were significantly more common in Indians compared to Chinese or Malays (32/18/21%, P=0.035) Inter-individual and inter-ethnic variations of docetaxel and doxorubicin pharmacokinetics or pharmacodynamics exist, but genotypic variability of the transcriptional regulators PAR, CAR and HNF4alpha cannot account for this variability.
    Matched MeSH terms: Polymorphism, Genetic
  8. Tan PO, Mustaffa N, Tan SS, Lee YY
    J R Coll Physicians Edinb, 2020 Sep;50(3):256-261.
    PMID: 32936098 DOI: 10.4997/JRCPE.2020.308
    Globally, the prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing rapidly and constitutes a significant healthcare burden due to associated complications including hepatic (cirrhosis and hepatocellular cancer) and non-hepatic (cardiovascular deaths) disorders. It is closely linked to insulin resistance and metabolic syndrome but moderate alcohol consumption frequently coexists. Recently, genetic polymorphisms were implicated in the development of non-obese NAFLD. Apart from liver biopsy, in order to assess for steatosis, fibrosis and non-alcoholic steatohepatitis (NASH), advances in non-invasive serum tests and elastography have provided similarly accurate, more accessible and safer alternatives for risk stratification. As for treatment in 2020, weight loss and lifestyle modification remain the central strategy. Unfortunately, no pharmacological agents have been approved thus far, but there are a number of potential therapies in the pipeline for fibrosis and NASH. Treatment of underlying metabolic disorders is important. While the term NAFLD was coined in the 1980s, more recent understanding may support a change in nomenclature highlighting its strong metabolic roots.
    Matched MeSH terms: Polymorphism, Genetic
  9. Tan SC
    J Gene Med, 2018 04;20(4):e3010.
    PMID: 29424105 DOI: 10.1002/jgm.3010
    Colorectal cancer is a leading form of cancer in both males and females. Early detection of individuals at risk of colorectal cancer allows proper treatment and management of the disease to be implemented, which can potentially reduce the burden of colorectal cancer incidence, morbidity and mortality. In recent years, the role of genetic susceptibility factors in mediating predisposition to colorectal cancer has become more and more apparent. Identification of high-frequency, low-penetrance genetic polymorphisms associated with the cancer has therefore emerged as an important approach which can potentially aid prediction of colorectal cancer risk. However, the overwhelming amount of genetic epidemiology data generated over the past decades has made it difficult for one to assimilate the information and determine the exact genetic polymorphisms that can potentially be used as biomarkers for colorectal cancer. This review comprehensively consolidates, based primarily on results from meta-analyses, the recent progresses in the search of colorectal cancer-associated genetic polymorphisms, and discusses the possible mechanisms involved.
    Matched MeSH terms: Polymorphism, Genetic
  10. Poh R, Tan JA, Deva JP, Poo D, Yong Y, Arjunan S
    West Indian Med J, 2012 Sep;61(6):569-73.
    PMID: 23441349
    To determine the activity of paraoxonase 1 (PON1) in keratoconus in a Malaysian population in comparison with non-keratoconic subjects.
    Matched MeSH terms: Polymorphism, Genetic
  11. Jayapalan JJ, Muniandy S, Chan SP
    PMID: 19058590
    Discrepancies in angiotensin-1 converting enzyme (ACE) allele genetic susceptibility with disease etiology have been attributed to ethnic differences. We investigated ACE gene polymorphism of the multiethnic Malaysian population by utilizing nested polymerase chain reaction. Allelic frequency of 0.65 and 0.35 for I and D allele, respectively in the pooled population was comparable with other Asian populations. A significant association was found between the Malaysian ethnic groups and ACE I/D genotype. The II genotype was found at higher frequency among the Malays but a greater frequency of DD genotype among Indians.
    Matched MeSH terms: Polymorphism, Genetic
  12. Poh R, Muniandy S
    PMID: 17539292
    The role of high-density lipoprotein associated paraoxonase (PON) 1 in protection against oxidative stress associated with the development of complications in diabetes mellitus has been reported. Variations in the PON1 gene, 55LM and 192QR have been described in different populations. These variations are known to be risk factors for heart disease, especially the L and R alleles. We have investigated the prevalence of both polymorphisms in the Malaysian population comprising the three major ethnic groups: Malay, Chinese and Indian, using polymerase chain reaction followed by restriction endonuclease digestion. The results show the pooled frequencies of L and R alleles were 0.91 and 0.54, respectively, similar to those in the Asian region. The frequency of the M allele was higher in Indians (p < 0.05), whereas the R allele was higher in both the Chinese and Malays compared to Indians (p < 0.05), indicating ethnic group-dependent genetic differences. The most common genotypic combination was LL/QR, followed by LL/RR. The genotype frequencies for the total Malaysian population showed a significant departure from Hardy-Weinberg equilibrium for the 55LM (p = 0.013) but not the 192QR (p = 0.056) polymorphisms. A strong linkage disequilibrium between L/55 and R/192 alleles was also observed. In the Malaysian population as a whole, Malays and Chinese showed a higher frequency of the R allele which is a risk factor for cardiovascular diseases.
    Matched MeSH terms: Polymorphism, Genetic*
  13. Mohd Yusoff N, Shirakawa T, Nishiyama K, Choo KE, Isa MN, Matsuo M
    PMID: 15906717
    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked red blood cell enzymopathy common in malaria endemic areas. Individuals affected by this disease show a wide variety of clinical signs of acute hemolytic anemia. Mutations of the G6PD gene in the Malay population with G6PD deficiency in Kelantan, a state in North East Malaysia were studied. Ninety-three individuals with G6PD deficiency were subjected to mutation analysis of the G6PD gene using polymerase chain reaction based techniques of multiplex PCR. Of the ninety-three DNA samples studied, molecular defects were identified in 80 cases (86%). Variants were heterogeneous - 28.7% were found to have a G to A nucleotide change at nucleotide 871 of the G6PD gene (G871A), corresponding to G6PD Viangchan. The other major mutations were G6PD Mediterranean, G6PD Vanua Lava, G6PD Coimbra, G6PD Kaiping, G6PD Orissa, G6PD Mahidol, G6PD Canton and G6PD Chatham. These results showed that there are heterogeneous mutations of the G6PD gene associated with G6PD deficiency and that G6PD Viangchan and G6PD Mediterranean account for the main variants in G6PD deficiency among the Malay population in Malaysia.
    Matched MeSH terms: Polymorphism, Genetic
  14. Ishak R, Khim LC
    PMID: 9280004
    A study was initiated to amplify by polymerase chain reaction (PCR), a short factor VIII gene fragment containing the Bcl I restriction site from hemophilia patients using published primer sequences. Preliminary findings indicated that the resulting fragment is 142 bp long. This fragment, when digested with Bcl I restriction enzyme produced two fragments, 99 bp and 43 bp in length. Polymorphism in the Bcl I region can be used to detect carrier state in the family members of the hemophiliacs.
    Matched MeSH terms: Polymorphism, Genetic/genetics*
  15. Yong HS, Chan KL, Dhaliwal SS, Cheong WH, Mak JW, Chiang GL
    PMID: 6108615
    Matched MeSH terms: Polymorphism, Genetic*
  16. Hii JL, Chew M, Vun YS, Nasir M, Chang MS
    PMID: 3238482
    Two separate observations from recent electrophoretic studies of the systematics and population genetics of laboratory-reared populations which had a long history of colonization in various laboratories, were found to be inconsistent with the present study which used wild-caught populations from East Malaysia. Reanalysis of the two data sets generally indicated a low amount of genetic variation in laboratory colonies. The latter is characterized by higher frequency of monomorphic loci, low average heterozygosity values and, in one extreme case, no variability at two loci. However, natural populations of An. balabacensis and An. leucosphyrus showed more protein variability by the use of polyacrylamide gel electrophoresis. Since laboratory-maintained mosquitoes are genetically and phenotypically different from those in the field, results of laboratory studies on the systematics and population genetics of Anopheles species complexes may be biased.
    Matched MeSH terms: Polymorphism, Genetic*
  17. Norliza C, Norni A, Anandjit S, Mohd Fazli MI
    Med J Malaysia, 2014 Aug;69 Suppl A:55-8.
    PMID: 25417952 MyJurnal
    This is a review of research done in the area of substance abuse in Malaysia. There were 109 articles related to substance abuse found in a search through a database dedicated to indexing all original data relevant to medicine published in Malaysia between the years 2000-2013. Only 39 articles were reviewed, and case series, case report, reviews and reports were excluded. Research reviewed include the epidemiology of substance abuse, genetics, treatment and its relation to health behaviour, and health management. Studies have shown that more males than females use drugs. There was also a high prevalence of blood-bourne virus diseases and sexually transmitted diseases among drug users. Two studies showed some genetic polymorphism (Cyp 3a4 gene and FAAH Pro129Thr) among heroin and amphetamine users respectively that may contribute to drug dependence. Study on pharmacological treatment for substance abuse were limited to methadone and it was shown to improve the quality of life of heroin dependant patients. Alternative treatments such as acupunture and spiritual approach play a role in the management of substance abuse. Data also showed that treatment centres for substance abuse are lacking facilities for screening, assessment and treatment for medical illness related to substance use, e.g. Hepatitis C and tuberculosis. Studies on the effectiveness of current drug rehabilitation centres were inconclusive.
    Matched MeSH terms: Polymorphism, Genetic
  18. Rohana AG, Loh KC, Tin SK, Soh CH, Nazaimoon WM, Fong KY, et al.
    Med J Malaysia, 2011 Jun;66(2):133-7.
    PMID: 22106694
    HLA-DQA1, -DQB1, and -DRB1 gene polymorphism were analyzed to study type 1 DM susceptibility in Malay patients from Southeast Asia (Malaysia and Singapore). Patients showed significant increases in the occurrence of DQA1*0501 (50.7% vs. 20.4%; RR = 3.97; Pc < 0.01), DQB1*0201 (48% vs. 19.1%; RR = 3.86; Pc < 0.05), and DRB1*0301 (38.7 vs. 6.8%; RR = 8.36; 95% Pc < 0.05). Conversely, significant decreases were noted in the occurrence of DQA1*0601 (14.7% vs. 35.2%; RR = 0.33; Pc = 0.008) and DQB1*0601 (4% vs. 23.5%; RR = 0.16; Pc < 0.05) in type 1 DM patients. Using a logistic regression model, we derived a risk prediction model for type 1 DM in our indigenous Malay population based on the identified HLA genotypes. The RR for type 1 DM increases by a factor of 5.68 for every unit increase in the number of DRB1*0301 allele (P < 0.001), and decreases by a factor of 0.18 per unit increase in the number of DQB1*0601 allele (P < 0.001). After adjusting for these two HLA genotypes, DQA1*0501, DQB1*0201 and DQA1*0601 were not statistically significant as risk predictors. The lower incidence of type 1 DM in the Malay population may be contributed by the genotypic combinations of DR and DQ genes as well as the linkage disequilibria between susceptible and protective alleles.
    Matched MeSH terms: Polymorphism, Genetic/genetics*
  19. Hayati AR, Zainal AI, Tan GC, Ong LC, Khoo TB
    Med J Malaysia, 2008 Dec;63(5):379-83.
    PMID: 19803295 MyJurnal
    Major congenital malformations occur in about 3% of newborn. Several studies have suggested that homozygosity for the C677T methylenetetrahydrofolate reductase (MTHFR) variant is a potential risk factor for neural tube defects (NTDs). It has been hypothesized that the maternal folic acid supplementation prevents NTDs by partially correcting reduced MTHFR activity associated with the variant form of the enzyme. This association has not been found in some ethnic groups. In this study, we attempted to assess the association between NTDs and MTHFR C677T in Malaysian Malay population. Results show that MTHFR 677TT genotype was absent in both patient and control groups.
    Matched MeSH terms: Polymorphism, Genetic/genetics*
  20. Pramudji H, Demes CM, Dewi K, Tasmini T, Ahmad HS
    Med J Malaysia, 2019 Oct;74(5):400-404.
    PMID: 31649216
    BACKGROUND: Interleukin-6 (IL-6) and C-Reactive Protein (CRP) are mediators of inflammatory responses and increase in people who are obese . The increase of IL-6 and CRP levels is modified by polymorphism of -174 G>C IL-6 gene.

    AIM: The purpose of this study was to investigate the relationship between -174 G>C IL-6 polymorphism gene on the level of IL-6 and CRP in the population of western Indonesia obese who are obese.

    METHODS: In this study, we examined 178 subjects consisting of 89 who are obese with BMI> 25, and controls with BMI between 18.5 and 23. Fasting blood was taken from each subject for the examination of IL-6 and CRP levels by the ELISA method. Determination of genotype -174 G>C IL-6 gene was examined by Polymerase Chain reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) methods.

    RESULTS: The results of this study showed increased levels of IL-6 and CRP in the obese group compared to the controls. In the obese group, CC genotype had higher CRP and lower IL-6 levels than the GC and GG genotypes. The frequency of CC genotype in the obese group was 47.2% compared with 28.1% in controls and this genotype was considered a risk factor for obesity. Carriers of the C genotype as a dominant or a recessive model had greater risk of obesity.

    CONCLUSION: It was concluded that the polymorphism - 174G>C IL-6 gene is a risk factor for obesity and is associated with increased levels of IL-6 and CRP in an obese group of the Western Indonesian ethnic population.

    Matched MeSH terms: Polymorphism, Genetic
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