Displaying publications 21 - 40 of 441 in total

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  1. Yap CK, Chong CM, Tan SG
    Environ Monit Assess, 2011 Mar;174(1-4):389-400.
    PMID: 20437264 DOI: 10.1007/s10661-010-1464-x
    It has been widely reported that allozyme frequency variation is a potential indicator of heavy metal-induced impacts in aquatic populations. In the present study, wild populations of horseshoe crab (Carcinoscorpius rotundicauda) were collected from contaminated and uncontaminated sites of Peninsular Malaysia. By adopting horizontal starch gel electrophoresis, seven enzyme systems were used to study allozyme polymorphisms. Nine polymorphic loci were observed in C. rotundicauda. The relationships of allozyme variations with the concentrations of Cd, Cu, Ni, and Zn in sediments and in muscle tissues of horseshoe crabs were determined. Based on genetic distance, the lower mean value of Nei's D (0.017) indicated that both of the contaminated populations of Kg. Pasir Puteh and Kuala Juru were very closely related when compared to the relatively uncontaminated Pantai Lido population. Higher heterozygosities were shown by the contaminated populations when compared to the uncontaminated population. Different allelic frequencies could be observed for the aldolase (ALD; E.C. 2.7.5.1) locus between the contaminated and uncontaminated populations of C. rotundicauda. The dendrogram of genetic relationships of the three populations of C. rotundicauda showed the same clustering pattern as the dendrograms are based on heavy metals in the sediments and in the horseshoe crabs' abdominal muscles. From the F statistics, the present study showed that the three populations of horseshoe crabs were considered to have undergone moderate genetic differentiation with a mean F (ST) value of 0.092 .The current results suggest that allozyme polymorphism in horseshoe crabs is a potential biomonitoring tool for metal contamination, although further validation is required.
    Matched MeSH terms: Polymorphism, Genetic*
  2. Prasankok P, Ota H, Toda M, Panha S
    Zoolog Sci, 2007 Feb;24(2):189-97.
    PMID: 17409732
    We examined allozyme variation in two camaenid tree snails, Amphidromus atricallosus and A. inversus, across two principal regions of Thailand and from Singapore, plus for A. inversus, one site in peninsular Malaysia. Using horizontal starch gel electrophoresis, 13 allozyme loci (11 polymorphic) were screened for A. atricallosus and 18 (5 polymorphic) for A. inversus. Heterozygosity was higher in A. atricallosus (Hexp=0.018-0.201, mean=0.085) than in A. inversus (Hexp=0-0.023, mean= 0.002). Genetic heterogeneity among samples was higher in A. inversus (Fst=0.965) than in A. atricallosus (Fst=0.781). Within A. atricallosus, populations were more differentiated in southern Thailand (Fst=0.551) than in eastern Thailand (Fst=0.144). The high Fst and low Hexp in populations of A. inversus suggest that this species is likely to have experienced a series of strong bottlenecks, perhaps occurring chiefly on offshore continental-shelf islands. The low Fst values of A. atricallosus in eastern Thailand suggest frequent gene flows among populations in this region. The southern and eastern samples of A. atricallosus exhibited fixed allele differences at four loci and great genetic distance (Nei's D=0.485-0.946), suggesting that these two samples may actually represent, or else be evolving into, separate species.
    Matched MeSH terms: Polymorphism, Genetic
  3. Li Z, Cui L, Zhao H, Du J, Gopinath SCB, Lakshmipriya T, et al.
    Dev Neurosci, 2021;43(1):53-62.
    PMID: 33849012 DOI: 10.1159/000515197
    OBJECTIVE: Brain-derived neurotrophic factor (BDNF) dysregulation is widely related with various psychiatric and neurological disorders, including schizophrenia, depression, Rett syndrome, and addiction, and the available evidence suggests that BDNF is also highly correlated with Parkinson's and Alzheimer's diseases.

    METHODS: The BDNF target sequence was detected on a capture probe attached on aluminum microcomb electrodes on the silicon wafer surface. A capture-target-reporter sandwich-type assay was performed to enhance the detection of the BDNF target.

    RESULTS: The limit of detection was noticed to be 100 aM. Input of a reporter sequence at concentrations >10 aM improved the detection of the target sequence by enhancing changes in the generated currents. Control experiments with noncomplementary and single- and triple-mismatches of target and reporter sequences did not elicit changes in current levels, indicating the selective detection of the BDNF gene sequence.

    CONCLUSION: The above detection strategy will be useful for the detection and quantification of BDNF, thereby aiding in the provision of suitable treatments for BDNF-related disorders.

    Matched MeSH terms: Polymorphism, Genetic
  4. 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*
  5. Naing C, Htet NH, Basavaraj AK, Nalliah S
    J Diabetes Metab Disord, 2018 Dec;17(2):333-343.
    PMID: 30918869 DOI: 10.1007/s40200-018-0349-3
    Background: This study aimed to synthesize evidence on the association between IL-10 gene (-819 C/T, -1082 A/G, -592 A/C) polymorphisms and the risk of developing diabetic nephropathy.

    Methods: A systematic literature search was done in health-related electronic databases. The search was limited to studies published in English until September 2017. We also checked the references of retrieved articles and relevant reviews for any additional studies. The methodological quality of the studies included in this review was assessed using the 'Scales for Quality Assessment'. The I2 test was used to quantify between-study heterogeneity. A value of I2 > 50% indicated substantial heterogeneity. For the pooled analysis, summary odds ratio (OR) and its 95% confidence interval (CI) in random effect model were used.

    Results: Eight case-control studies (1192 cases with diabetic nephropathy and 2399 controls) met the inclusion criteria. Three groups of people namely Africans, Asians and Caucasians were included in this review. There were significant protective effects of SNP -819 C/T in overall population (OR 0.32, 95% CI 0.26-0.4) and - 1082 A/G SNP in the Asian population (OR 0.64, 95% CI 0.47-0.86) on diabetic nephropathy in the recessive model. There was no significant effect of -592 A/C on diabetic nephropathy.

    Conclusion: The findings suggest the protective effects of -1082A/G and -819G/A polymorphisms on the risk of developing diabetic nephropathy in type 2 diabetes mellitus, especially in the Asian population. Well- designed, prospective studies with sufficient number of participants are recommended to substantiate these findings.

    Matched MeSH terms: Polymorphism, Genetic
  6. Tan, Soon Guan
    MyJurnal
    In various biological studies, for example those in population genetics, conservation biology, forensic science, gene mapping, breed, strain and population characterization and identification, marker assisted selection and the identification of cryptic species complexes, codominant genetic markers play important roles. The information that can be gained from them are far superior than those from dominant markers like random amplified polymorphic DNA (RAPD), amplified fragment length polymorphisms (AFLP), direct amplification of length polymorphisms (DALP) and randomly amplified microsatellites (RAM) or inter simple sequence repeats (ISSR).
    Matched MeSH terms: Polymorphism, Genetic
  7. Zilfalil BA, Hoh BP, Nizam MZ, Liza-Sharmini AT, Teh LK, Ismail R
    J Clin Pharm Ther, 2006 Dec;31(6):637-40.
    PMID: 17176369
    Seventeen single nucleotide polymorphisms (SNPs) have been identified so far, within the beta-2 receptor (beta(2) AR) gene. The presence of so many SNPs within the beta(2) AR gene causes a problem, for those studying beta(2) AR pharmacogenetics, in relation to which SNPs to choose. Most of the work has focused on the three common SNPs within the coding block (alleles 16, 27 and 164) and the techniques developed have been for these three functionally important alleles.
    Matched MeSH terms: Polymorphism, Genetic*
  8. Karon A, Ula K
    J Biol Regul Homeost Agents, 2021 1 20;35(1 Suppl. 1):19-26.
    PMID: 33463140
    Matched MeSH terms: Polymorphism, Genetic
  9. Tan EL, Peh SC, Sam CK
    J Med Virol, 2003 Feb;69(2):251-7.
    PMID: 12683415
    Nasopharyngeal carcinoma, a malignancy associated closely with Epstein-Barr virus (EBV), is prevalent among Chinese of Southern China origin. Epidemiological studies indicate a high prevalence of EBV in Asia with viral isolates having typical characteristics of the putative viral oncogene, latent membrane protein 1 (LMP-1), such as the loss of the Xho1 restriction site in Exon 1 and the 30-bp deletion in Exon 3. The EBV LMP-1 gene from throat washings of 120 nasopharyngeal carcinoma patients and 14 healthy individuals were analyzed. Similar analyses were also carried out on 30 and 12 postnasal space biopsies from nasopharyngeal carcinoma patients and healthy individuals, respectively. The 30-bp deletion was detected in 20% of nasopharyngeal carcinoma throat washes and in 100% of nasopharyngeal carcinoma postnasal space biopsies. Interestingly, 16% of the nasopharyngeal carcinoma biopsies possessed both the deleted and the undeleted variants, suggestive of dual infections. The notion of dual infections in nasopharyngeal carcinoma was further supported by the coexistence of both "F" and "f" (BamH1F region) EBV variants in 11% of the nasopharyngeal carcinoma biopsies. All of the throat washes and biopsies from the healthy controls showed the undeleted variant. The loss of the Xho1 restriction site was found with higher frequency both in throat washes and biopsies from patients with nasopharyngeal carcinoma. The discrepancy in the frequency of the 30-bp deletion between throat washes (20%) and postnasal space biopsies (100%) was an indication that this deletion is specific for viral isolates from primary tumour sites.
    Matched MeSH terms: Polymorphism, Genetic*
  10. Norazah A, Rasinah WZ, Zaili Z, Aminuddin A, Ramelah M
    Malays J Pathol, 2009 Jun;31(1):29-34.
    PMID: 19694311 MyJurnal
    This study was conducted to determine whether there was any genetic heterogeneity among Helicobacter pylori strains isolated from the antrum and corpus of the same individual in a Malaysian population and to determine the presence of heterogeneous susceptibility of the isolates by comparing PCR-RAPD and antibiotic profiles. Forty-four H. pylori isolates cultured from the antrum and corpus of 22 patients were analyzed. Antibiotic susceptibility testing was carried out by minimum inhibitory concentration determination, using E-Test method strips. PCR-RAPD was carried out on all the strains and the profiles generated were analysed for cluster analysis. Twenty-nine different PCR-RAPD profiles were observed in the 44 isolates. Fifteen pairs of the isolates from the same patients had the same PCR-RAPD patterns while in 7 pairs, the profiles were different. The strains were clustered into 2 separate clusters at a low coefficient of similarity, where most of the strains were in cluster 1. The degree of similarity was very low among most of the isolates. Most of the patients (16 of 22) were infected with strains that have the same antibiotic susceptibility profiles. Out of these, only 10 pairs shared the same PCR-RAPD and antibiotic profiles. Five pairs of isolates with similar PCR-RAPD profiles differed in their antibiotic profiles due to metronidazole resistance in one of the sites. A large degree of genetic heterogeneity was observed among H. pylori strains circulating among Malaysian patients. An individual patient can be infected with multiple strains and the strains can be antibiotic resistant.
    Matched MeSH terms: Polymorphism, Genetic
  11. Vasudevan R, Ismail P, Jaafar N, Mohamad N, Etemad E, Wan Aliaa W, et al.
    Balkan J. Med. Genet., 2014 Jun;17(1):37-40.
    PMID: 25741213 DOI: 10.2478/bjmg-2014-0023
    The aim of this study was to determine the association of the c.894G>T; p.Glu298Asp polymorphism and the variable number tandem repeat (VNTR) polymorphism of the endothelial nitric oxide synthase (eNOS) gene and c.181C>T polymorphism of the bradykinin type 2 receptor gene (B2R) in Malaysian end-stage renal disease (ESRD) subjects. A total of 150 ESRD patients were recruited from the National Kidney Foundation's (NKF)dialysis centers in Malaysia and compared with 150 normal healthy individuals. Genomic DNA was extracted from buccal cells of all the subjects. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was carried out to amplify the products and the restricted fragments were separated by agarose gel electrophoresis. Statistical analyses were carried out using software where a level of p <0.05 was considered to be statistically significant. The genotypic and allelic frequencies of the B2R gene (c.181C>T, 4b/a) and eNOS gene (c.894G>T) polymorphisms were not statistically significant (p >0.05) when compared to the control subjects. The B2R and eNOS gene polymorphisms may not be considered as genetic susceptibility markers for Malaysian ESRD subjects.
    Matched MeSH terms: Polymorphism, Genetic
  12. Chua CY, Lee PC, Lau TY
    J Genet, 2017 Sep;96(4):653-663.
    PMID: 28947714
    The apical membrane antigen-1 (AMA-1) of Plasmodium spp. is a merozoite surface antigen that is essential for the recognition and invasion of erythrocytes. Polymorphisms occurring in this surface antigen will cause major obstacles in developing effective malaria vaccines based on AMA-1. The objective of this study was to characterize ama1 gene in Plasmodium knowlesi isolates from Sabah. DNA was extracted from blood samples collected from Keningau, Kota Kinabalu and Kudat. The Pkama1 gene was amplified using nested PCR and subjected to bidirectional sequencing. Analysis of DNA sequence revealed that most of the nucleotide polymorphisms were synonymous and concentrated in domain I of PkAMA-1. Forteen haplotypes were identified based on amino acid variations and haplotype K5 was the most common haplotype. dN/dS ratios implied that purifying selection was prevalent in Pkama1 gene. Fu and Li's D and F values further provided evidence of negative selection acting on domain II of Pkama1. Lownucleotide diversitywas also detected for the Pkama1 sequences,which is similar to reports on Pkama1 from Peninsular Malaysia and Sarawak. The presence of purifying selection and low nucleotide diversity indicated that domain II of Pkama1 can be used as a target for vaccine development.
    Matched MeSH terms: Polymorphism, Genetic*
  13. Ramachandran V, Ismail P, Stanslas J, Shamsudin N
    PMID: 19243623 DOI: 10.1186/1475-2840-8-11
    The renin-angiotensin aldosterone system (RAAS) plays an important role in regulating the blood pressure and the genetic polymorphisms of RAAS genes has been extensively studied in relation to the cardiovascular diseases in various populations with conflicting results. The aim of this study was to determine the association of five genetic polymorphisms (A6G and A20C of angiotensinogen (AGT), MboI of renin, Gly460Trp of aldosterone synthase and Lys173Arg of adducin) of RAAS genes in Malaysian essential hypertensive and type 2 diabetic subjects.
    Matched MeSH terms: Polymorphism, Genetic/genetics*
  14. Ashkani S, Rafii MY, Sariah M, Siti Nor Akmar A, Rusli I, Abdul Rahim H, et al.
    Genet. Mol. Res., 2011 Jul 06;10(3):1345-55.
    PMID: 21751161 DOI: 10.4238/vol10-3gmr1331
    Among 120 simple sequence repeat (SSR) markers, 23 polymorphic markers were used to identify the segregation ratio in 320 individuals of an F(2) rice population derived from Pongsu Seribu 2, a resistant variety, and Mahsuri, a susceptible rice cultivar. For phenotypic study, the most virulent blast (Magnaporthe oryzae) pathotype, P7.2, was used in screening of F(2) population in order to understand the inheritance of blast resistance as well as linkage with SSR markers. Only 11 markers showed a good fit to the expected segregation ratio (1:2:1) for the single gene model (d.f. = 1.0, P < 0.05) in chi-square (χ(2)) analyses. In the phenotypic data analysis, the F(2) population segregated in a 3:1 (R:S) ratio for resistant and susceptible plants, respectively. Therefore, resistance to blast pathotype P7.2 in Pongsu Seribu 2 is most likely controlled by a single nuclear gene. The plants from F(2) lines that showed resistance to blast pathotype P7.2 were linked to six alleles of SSR markers, RM168 (116 bp), RM8225 (221 bp), RM1233 (175 bp), RM6836 (240 bp), RM5961 (129 bp), and RM413 (79 bp). These diagnostic markers could be used in marker assisted selection programs to develop a durable blast resistant variety.
    Matched MeSH terms: Polymorphism, Genetic
  15. NurWaliyuddin HZ, Norazmi MN, Edinur HA, Chambers GK, Panneerchelvam S, Zafarina Z
    PLoS One, 2015;10(11):e0141536.
    PMID: 26565719 DOI: 10.1371/journal.pone.0141536
    The aboriginal populations of Peninsular Malaysia, also known as Orang Asli (OA), comprise three major groups; Semang, Senoi and Proto-Malays. Here, we analyzed for the first time KIR gene polymorphisms for 167 OA individuals, including those from four smallest OA subgroups (Che Wong, Orang Kanaq, Lanoh and Kensiu) using polymerase chain reaction-sequence specific primer (PCR-SSP) analyses. The observed distribution of KIR profiles of OA is heterogenous; Haplotype B is the most frequent in the Semang subgroups (especially Batek) while Haplotype A is the most common type in the Senoi. The Semang subgroups were clustered together with the Africans, Indians, Papuans and Australian Aborigines in a principal component analysis (PCA) plot and shared many common genotypes (AB6, BB71, BB73 and BB159) observed in these other populations. Given that these populations also display high frequencies of Haplotype B, it is interesting to speculate that Haplotype B may be generally more frequent in ancient populations. In contrast, the two Senoi subgroups, Che Wong and Semai are displaced toward Southeast Asian and African populations in the PCA scatter plot, respectively. Orang Kanaq, the smallest and the most endangered of all OA subgroups, has lost some degree of genetic variation, as shown by their relatively high frequency of the AB2 genotype (0.73) and a total absence of KIR2DL2 and KIR2DS2 genes. Orang Kanaq tradition that strictly prohibits intermarriage with outsiders seems to have posed a serious threat to their survival. This present survey is a demonstration of the value of KIR polymorphisms in elucidating genetic relationships among human populations.
    Matched MeSH terms: Polymorphism, Genetic*
  16. 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
  17. Lian LH, Lau TP, Ching AS, Chua KH
    Genet. Mol. Res., 2012;11(2):863-71.
    PMID: 22576914 DOI: 10.4238/2012.April.10.2
    Systemic lupus erythematosus (SLE) is an autoimmune disease that causes systemic damage, involving auto-reactive antibodies and over-deposition of immune complexes. Susceptibility to SLE is believed to be multifactorial, and genetics is one of the proven etiological factors; it can affect SLE development, severity and prognosis. We investigated a possible association between the angiotensin-converting enzyme gene and susceptibility to SLE in the Malaysian population. PCR was employed for the determination of I/D dimorphism of this gene. The I allele was more frequent than the D allele in both the SLE patients (N = 170) and healthy controls (N = 190). However, there was no significant difference in the distribution of these two alleles between both groups studied (χ(2) = 0.284, P > 0.05). Interestingly, the DD homozygous genotype scored notably higher in the healthy control group (χ(2) = 7.568, P < 0.05), while the ID heterozygote was observed to be significantly associated with SLE (χ(2) = 11.143, P < 0.05). In conclusion, with respect to the Malaysian population, the DD genotype might play a protective role in the development of SLE while in contrast, those who carry the ID genotype might be at potential risk for onset of this disease.
    Matched MeSH terms: Polymorphism, Genetic*
  18. Say YH, Ling KH, Duraisamy G, Isaac S, Rosli R
    BMC Cardiovasc Disord, 2005;5(1):7.
    PMID: 15811183
    Essential hypertension is a major public health concern worldwide where its prevalence accounts for various cerebrovascular diseases. A common molecular variant of angiotensinogen (AGT), the precursor of potent vasoactive hormone angiotensin II, has been incriminated as a marker for genetic predisposition to essential hypertension in some ethnics. This case-control study was designed not only to determine the association of the AGT M235T gene variants with essential hypertension, but also its relationship to Plasma Renin Activity (PRA) in subjects attending the Health Clinic, Kuala Lumpur, Malaysia.
    Matched MeSH terms: Polymorphism, Genetic
  19. Saha N
    Hum. Hered., 1991;41(1):47-52.
    PMID: 2050382
    A total of 627 subjects comprising 455 Chinese, 127 Dravidian Indians and 45 Malays were investigated for serum Apo A-IV polymorphism. The frequency of Apo A-IV*2 was found to be significantly higher (p less than 0.001) in Indians (0.043) compared to that in the Chinese (0.010) and Malays (0.011). The frequency of A-IV*3 was found to be around 0.02 in all the ethnic groups. A low frequency of A-IV*4 (less than 0.01) was observed in the Chinese and Indians. The phenotypic distribution of Apo A-IV was at Hardy-Weinberg equilibrium in the three ethnic groups.
    Matched MeSH terms: Polymorphism, Genetic
  20. Choong ML, Koay ES, Khaw MC, Aw TC
    Hum. Hered., 1999 Jan;49(1):31-40.
    PMID: 9858855
    The allele frequencies for the apolipoprotein B (apo B) 5'-Ins/Del and 3'-VNTR polymorphisms varied significantly (p < 0.01) among Singaporeans of Chinese, Malay and Indian descent. We calculated the unbiased expected heterozygosities for the 5'-Ins/Del polymorphism as 0.3357, 0.1984 and 0.2418, and for the 3'-VNTR as 0.5980, 0.5260 and 0.6749, respectively, in the Chinese, Malays and Indians. Compared to heterozygosities reported for other populations, the Singaporeans differed from most Caucasians in having significantly lower values but were closely related to other non-Caucasians. Thirteen alleles, with a bimodal distribution, were observed at the 3'-VNTR polymorphic locus; the alleles occurring most frequently among the Chinese and Malays were of 35 or 53 repeats, and among the Indians, of 37 or 47 repeats. The Del allele was associated with elevated serum cholesterol (p = 0.023), LDL-cholesterol (LDL-C) (p = 0.001) in the Chinese, and apo B (p = 0.007) in the Indians. Likewise, the larger 3'-VNTR alleles (> 41 repeats) were associated with raised cholesterol (p = 0.018), LDL-C (p = 0.025), and triglyceride (p = 0.001) in the Chinese. The two polymorphisms were not in significant linkage disequilibrium (D = -0.0029, p = 0.494) in the three ethnic groups.
    Matched MeSH terms: Polymorphism, Genetic/genetics*
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