Displaying publications 41 - 59 of 59 in total

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  1. Chua YA, Abdullah WZ, Yusof Z, Gan SH
    Turk J Med Sci, 2015;45(4):913-8.
    PMID: 26422867
    BACKGROUND/AIM: VKORC1 and CYP2C9 genetic polymorphisms may not accurately predict warfarin dose requirements. We evaluated an existing warfarin dosing algorithm developed for Malaysian patients that was based only on VKORC1 and CYP2C9 genes.

    MATERIALS AND METHODS: Five Malay patients receiving warfarin maintenance therapy were investigated for their CYP2C9*2, CYP2C9*3, and VKORC1-1639G>A genotypes and their vitamin K-dependent (VKD) clotting factor activities. The records of their daily warfarin doses and international normalized ratio (INR) 2 years prior to and after the measurement of VKD clotting factors activities were acquired. The mean warfarin doses were compared with predicted warfarin doses calculated from a genotypic-based dosing model developed for Asians.

    RESULTS: A patient with the VKORC1-1639 GA genotype, who was supposed to have higher dose requirements, had a lower mean warfarin dose similar to those having the VKORC1-1639 AA genotype. This discrepancy may be due to the coadministration of celecoxib, which has the potential to decrease warfarins metabolism. Not all patients' predicted mean warfarin doses based on a previously developed dosing algorithm for Asians were similar to the actual mean warfarin dose, with the worst predicted dose being 54.34% higher than the required warfarin dose.

    CONCLUSION: Multiple clinical factors can significantly change the actual required dose from the predicted dose from time to time. The additions of other dynamic variables, especially INR, VKD clotting factors, and concomitant drug use, into the dosing model are important in order to improve its accuracy.

    Matched MeSH terms: Vitamin K Epoxide Reductases/genetics*
  2. Chin KY, Ima-Nirwana S
    Nutrients, 2014 Apr 10;6(4):1424-41.
    PMID: 24727433 DOI: 10.3390/nu6041424
    Recent studies have found conflicting evidence on the role of α-tocopherol (αTF) on bone health. This nonsystematic review aimed to summarize the current evidence on the effects of αTF on bone health from cell culture, animal, and human studies in order to clarify the role of αTF on bone health. Our review found that αTF exerted beneficial, harmful or null effects on bone formation cells. Animal studies generally showed positive effects of αTF supplementation on bone in various models of osteoporosis. However, high-dose αTF was possibly detrimental to bone in normal animals. Human studies mostly demonstrated a positive relationship between αTF, as assessed using high performance liquid chromatography and/or dietary questionnaire, and bone health, as assessed using bone mineral density and/or fracture incidence. Three possible reasons high dosage of αTF can be detrimental to bone include its interference with Vitamin K function on bone, the blocking of the entry of other Vitamin E isomers beneficial to bone, and the role of αTF as a prooxidant. However, these adverse effects have not been shown in human studies. In conclusion, αTF may have a dual role in bone health, whereby in the appropriate doses it is beneficial but in high doses it may be harmful to bone.
    Matched MeSH terms: Vitamin K/pharmacology
  3. Lee LH, Zainal N, Azman AS, Eng SK, Ab Mutalib NS, Yin WF, et al.
    Int J Syst Evol Microbiol, 2014 Sep;64(Pt 9):3297-306.
    PMID: 24994773 DOI: 10.1099/ijs.0.065045-0
    Two novel actinobacteria, strains MUSC 135(T) and MUSC 137, were isolated from mangrove soil at Tanjung Lumpur, Malaysia. The 16S rRNA gene sequence similarity and DNA-DNA relatedness between strains MUSC 135(T) and MUSC 137 were 100 % and 83±3.2 %, confirming that these two strains should be classified in the same species. Strain MUSC 135(T) exhibited a broad-spectrum bacteriocin against the pathogens meticillin-resistant Staphylococcus aureus (MRSA) strain ATCC BAA-44, Salmonella typhi ATCC 19430(T) and Aeromonas hydrophila ATCC 7966(T). A polyphasic approach was used to study the taxonomy of MUSC 135(T), and it showed a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Streptomyces. The diamino acid of the cell-wall peptidoglycan was ll-diaminopimelic acid. The predominant menaquinones were MK-9(H6), MK-9(H4) and MK-9(H8). Polar lipids detected were a lipid, an aminolipid, a phospholipid, phosphatidylinositol, phosphatidylethanolamine and two glycolipids. The predominant cellular fatty acids (>10.0 %) were anteiso-C15 : 0 (20.8 %), iso-C16 : 0 (18.0 %), iso-C15 : 0 (12.2 %) and anteiso-C17 : 0 (11.6 %). The whole-cell sugars were ribose, glucose and mannose. These results suggested that MUSC 135(T) should be placed within the genus Streptomyces. Phylogenetic analysis based on the 16S rRNA gene sequence exhibited that the most closely related strains were Streptomyces cinereospinus NBRC 15397(T) (99.18 % similarity), Streptomyces mexicanus NBRC 100915(T) (99.17 %) and Streptomyces coeruleofuscus NBRC 12757(T) (98.97 %). DNA-DNA relatedness between MUSC 135(T) and closely related type strains ranged from 26.3±2.1 to 49.6±2.5 %. BOX-PCR fingerprint comparisons showed that MUSC 135(T) exhibited a unique DNA profile. The DNA G+C content determined was 70.7±0.3 mol%. Based on our polyphasic study of MUSC 135(T), the strain merits assignment to a novel species, for which the name Streptomyces pluripotens sp. nov. is proposed. The type strain is MUSC 135(T) ( = MCCC 1K00252(T) = DSM 42140(T)).
    Matched MeSH terms: Vitamin K 2/analogs & derivatives; Vitamin K 2/chemistry
  4. Chen X, Li QY, Li GD, Xu FJ, Jiang Y, Han L, et al.
    Antonie Van Leeuwenhoek, 2016 Sep;109(9):1177-83.
    PMID: 27260265 DOI: 10.1007/s10482-016-0718-1
    A novel aerobic, non-motile, Gram-positive, rod-shaped actinobacterium, designated YIM 100951(T), was isolated from the faeces of civets (Viverra zibetha) living in the National Nature Protect Region in Selangor, Malaysia. Strain YIM 100951(T) shows high similarities with Microbacterium barkeri DSM 20145(T) (97.6 %), Microbacterium oryzae MB10(T) (97.3 %), Microbacterium lemovicicum ViU22(T) (97.1 %) and Microbacterium indicum BBH6(T) (97.0 %) based on their 16S rRNA genes. However, phylogenetic analysis showed that strain YIM 100951(T) formed a clade with Microbacterium halotolerans YIM 70130(T) (96.7 %), Microbacterium populi 10-107-8(T) (96.7 %) and Microbacterium sediminis YLB-01(T) (96.9 %). DNA-DNA hybridization was carried out between strains YIM 100951(T) and M. barkeri DSM 20145(T), the result showed a value of 23.2 ± 4.5 %. In addition, some of the physiological, biochemical and chemotaxonomic characteristics of strain YIM 100951(T) are different from the closely related strains. Thus, we suggest that strain YIM 100951(T) represents a novel species of the genus Microbacterium, for which the name Microbacterium gilvum sp. nov. is proposed. The type strain is YIM 100951(T) (=DSM 26235(T) = CCTCC AB 2012971(T)).
    Matched MeSH terms: Vitamin K 2/metabolism
  5. Lee LH, Azman AS, Zainal N, Eng SK, Mutalib NA, Yin WF, et al.
    Int J Syst Evol Microbiol, 2014 Oct;64(Pt 10):3513-3519.
    PMID: 25056298 DOI: 10.1099/ijs.0.062414-0
    Strain MUSC 115(T) was isolated from mangrove soil of the Tanjung Lumpur river in the state of Pahang, Peninsular Malaysia. Cells of this strain stained Gram-positive and were non-spore-forming, short rods that formed yellowish-white colonies on different agar media. The taxonomy of strain MUSC 115(T) was studied by a polyphasic approach, and the organism showed a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Microbacterium. The cell-wall peptidoglycan was of type B2β, containing the amino acids ornithine, alanine, glycine, glutamic acid and homoserine. The muramic acid was of the N-glycolyl form. The predominant menaquinones detected were MK-12, MK-13 and MK-11. The polar lipids consisted of phosphatidylglycerol, phosphoglycolipid, diphosphatidylglycerol, two unidentified lipids, three unidentified phospholipids and four unidentified glycolipids. The major fatty acids of the cell membrane were anteiso-C15:0 and anteiso-C17:0. The whole-cell sugars detected were ribose, glucose, mannose and galactose. Based on the 16S rRNA gene sequence, strain MUSC 115(T) showed the highest sequence similarity to Microbacterium immunditiarum SK 18(T) (98.1%), M. ulmi XIL02(T) (97.8%) and M. arborescens DSM 20754(T) (97.5%) and lower sequence similarity to strains of other species of the genus Microbacterium. DNA-DNA hybridization experiments revealed a low level of DNA-DNA relatedness (less than 24%) between strain MUSC 115(T) and the type strains of closely related species. Furthermore, BOX-PCR fingerprint comparison also indicated that strain MUSC 115(T) represented a unique DNA profile. The DNA G+C content determined was 70.9 ± 0.7 mol%, which is lower than that of M. immunditiarum SK 18(T). Based on the combination of genotypic and phenotypic data, it is proposed that strain MUSC 115(T) represents a novel species of the genus Microbacterium, for which the name Microbacterium mangrovi sp. nov. is proposed. The type strain is MUSC 115(T) ( = MCCC 1K00251(T) = DSM 28240(T) = NBRC 110089(T)).
    Matched MeSH terms: Vitamin K 2/chemistry
  6. Chua YA, Abdullah WZ, Yusof Z, Gan SH
    Biomed Res Int, 2014;2014:316310.
    PMID: 24790995 DOI: 10.1155/2014/316310
    The vitamin K epoxide reductase complex 1 gene (VKORC1) is commonly assessed to predict warfarin sensitivity. In this study, a new nested allele-specific multiplex polymerase chain reaction (PCR) method that can simultaneously identify single nucleotide polymorphisms (SNPs) at VKORC1 381, 861, 5808, and 9041 for haplotype analysis was developed and validated. Extracted DNA was amplified in the first PCR DNA, which was optimized by investigating the effects of varying the primer concentrations, annealing temperature, magnesium chloride concentration, enzyme concentration, and the amount of DNA template. The amplification products produced from the first round of PCR were used as templates for a second PCR amplification in which both mutant and wild-type primers were added in separate PCR tubes, followed by optimization in a similar manner. The final PCR products were resolved by agarose gel electrophoresis and further analysed by using a VKORC1 genealogic tree to infer patient haplotypes. Fifty patients were identified to have H1H1, one had H1H2, one had H1H7, 31 had either H1H7 or H1H9, one had H1H9, eight had H7H7, and one had H8H9 haplotypes. This is the first method that is able to infer VKORC1 haplotypes using only conventional PCR methods.
    Matched MeSH terms: Vitamin K Epoxide Reductases/genetics*
  7. Choi EK, Lee YS, Chern AKC, Jiampo P, Chutinet A, Hanafy DA, et al.
    Open Heart, 2020 11;7(2).
    PMID: 33184127 DOI: 10.1136/openhrt-2020-001343
    BACKGROUND AND PURPOSE: Real-world data about treatment convenience and satisfaction in Asian non-valvular atrial fibrillation (NVAF) patients after switching from vitamin K antagonists (VKAs) to non-VKA oral anticoagulants were evaluated.

    METHODS: In this non-interventional study involving 49 sites across five countries in Southeast Asia and South Korea, 379 stable NVAF patients who switched from VKA therapy to dabigatran during routine clinical practice were recruited and followed up for 6 months. Treatment convenience and satisfaction were evaluated using Perception on Anticoagulant Treatment Questionnaire-2 (PACT-Q2). Through post hoc analysis, factors associated with improved treatment convenience scores at visit 2 were described.

    RESULTS: Treatment convenience and satisfaction significantly improved after switching from VKAs to dabigatran at visit 2 and visit 3 (convenience: p<0.001 each vs baseline; satisfaction: p=0.0174 (visit 2), p=0.0004 (visit 3) compared with baseline). Factors predictive of higher (>80th percentile) response on treatment convenience were female sex, younger age (<75 years), higher baseline stroke risk, higher creatinine clearance and absence of concomitant hypertension, stroke or gastrointestinal diseases.

    CONCLUSION: Dabigatran was associated with a significant improvement in treatment convenience and satisfaction after switching from VKAs when used for stroke prevention in NVAF patients from Southeast Asia and South Korea.

    Matched MeSH terms: Vitamin K/antagonists & inhibitors*
  8. Lee YS, Oh YS, Choi EK, Chern AKC, Jiampo P, Chutinet A, et al.
    Open Heart, 2021 12;8(2).
    PMID: 34857666 DOI: 10.1136/openhrt-2021-001745
    PURPOSE: Dabigatran is a direct thrombin inhibitor approved for stroke prophylaxis in patients with non-valvular atrial fibrillation (NVAF). Real-world data about patient preference, satisfaction and convenience in patients in Asia are not available. The study aimed to explore the perception of patients with newly diagnosed NVAF regarding dabigatran versus vitamin K antagonists (VKAs), when used for stroke prevention.

    PATIENTS AND METHODS: This was a multinational, multicentre, non-interventional study involving 49 sites across 5 countries in South East Asia and South Korea where 934 patients newly diagnosed with NVAF were initiated on either dabigatran (N=591) or VKA (N=343). Data were collected at baseline and over two follow-up visits across 6 months. Treatment satisfaction and patient convenience were evaluated using the Perception on Anticoagulant Treatment Questionnaire-2 (PACT-Q2).

    RESULTS: The mean age of the patients was 65.9±10.4 years, and 64.2% were male. Mean CHA2DS2-VASc score was 2.4±1.5, and mean HAS-BLED score was 1.2±0.9. At baseline, patients initiated on dabigatran had higher stroke risk, bleeding risk, creatinine clearance and proportion of patients with concomitant illnesses compared with patients initiated on VKAs. Treatment convenience was perceived to be significantly better with dabigatran versus VKAs at visits 2 and 3 (p=0.0423 and 0.0287, respectively). Treatment satisfaction was significantly better with dabigatran compared with VKAs at visit 3 (p=0.0300).

    CONCLUSION: In this study, dabigatran is associated with better patient perception in terms of treatment convenience and satisfaction compared with VKAs when used for stroke prevention in newly diagnosed NVAF patients from South East Asia and South Korea.

    TRIAL REGISTRATION NUMBER: NCT02849509.

    PLAIN LANGUAGE SUMMARY: Patient satisfaction with dabigatran versus VKAs in South East Asia. Patients with atrial fibrillation are at high risk of stroke and require anticoagulants for stroke prevention. Two such anticoagulants are dabigatran and VKAs. We wanted to compare the extent of satisfaction and treatment convenience among newly diagnosed patients with atrial fibrillation from the South East Asian region when they were given either dabigatran or VKAs. Consenting patients filled out a standardised questionnaire called the PACT-Q2 over three visits after they were started on either dabigatran (591 patients) or VKAs (343 patients). We found that satisfaction and convenience were significantly higher when patients received dabigatran than when they received VKAs.

    Matched MeSH terms: Vitamin K/antagonists & inhibitors*
  9. Aw YK, Ong KS, Lee LH, Cheow YL, Yule CM, Lee SM
    Front Microbiol, 2016;7:219.
    PMID: 26973605 DOI: 10.3389/fmicb.2016.00219
    Emergence of antimicrobial resistance coupled with the slowdown in discovery of new antimicrobial compounds points to serious consequences for human health. Therefore, scientists are looking for new antimicrobial compounds from unique and understudied ecosystems such as tropical peat swamp forests. Over the course of isolating antimicrobial producing bacteria from North Selangor tropical peat swamp forest, Malaysia, a Gram variable, rod shaped, endospore forming, facultative anaerobic novel strain MSt1(T) that exerts potent and broad spectrum antimicrobial activity was isolated. Phylogenetic analysis using 16S rRNA gene sequences showed that strain MSt1(T) belonged to the genus Paenibacillus with the highest similarity to Paenibacillus elgii SD17(T) (99.5%). Whole genome comparison between strain MSt1(T) with its closely related species using average nucleotide identity (ANI) revealed that similarity between strain MSt1(T) with P. elgii B69 (93.45%) and Paenibacillus ehimensis A2 (90.42%) was below the recommended threshold of 95%. Further analysis using in silico pairwise DDH also showed that similarity between strain MSt1(T) with P. elgii B69 (55.4%) and P. ehimensis A2 (43.7%) was below the recommended threshold of 70%. Strain MSt1(T) contained meso-diaminopilemic acid in the cell wall and MK-7 as the major menaquinone. The major fatty acids of strain MSt1(T) were anteiso-C15:0 (48.2%) and C16:0 (29.0%) whereas the polar lipid profile consisted of phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, one unknown lipid, two unknown glycolipids, and one unknown phospholipid. Total DNA G+C content of strain MSt1(T) was 51.5 mol%. The extract from strain MSt1(T) exerted strong antimicrobial activity against Escherichia coli ATCC 25922 (MIC = 1.5 μg/mL), MRSA ATCC 700699 (MIC = 25 μg/mL) and Candida albicans IMR (MIC = 12.5 μg/mL). Partially purified active fraction exerted a strong effect against E. coli ATCC 25922 resulting in cell rupture when viewed with SEM. Based on distinctive taxonomic differences between strain MSt1(T) when compared to its closely related type species, we propose that strain MSt1(T) represents a novel species within the genus of Paenibacillus, for which the name Paenibacillus tyrfis sp. nov. (= DSM 100708(T) = MCCC 1K01247(T)) is proposed.
    Matched MeSH terms: Vitamin K 2
  10. Ng ZY, Fang BZ, Li WJ, Tan GYA
    Int J Syst Evol Microbiol, 2019 Oct;69(10):3031-3040.
    PMID: 31310190 DOI: 10.1099/ijsem.0.003587
    Three novel actinobacterial strains, designated as TPS16T, TPS81 and TPS83, were isolated from a sample of marine sediment collected from Tioman Island, Malaysia. The strains formed abundant branched substrate mycelia without fragmentation along with production of blue spores and blue diffusible pigment on soybean meal agar. The strains could grow at pH ranging from pH 6 to 12 and in 0-8 % (w/v) NaCl. Cell-wall hydrolysis showed the presence of meso-diaminopimelic acid. The strains were closely related to Marinactinospora thermotolerans SCSIO 00652T (97.60 %) and Marinactinospora endophytica YIM 690053T (96.87 %) based on phylogenetic analysis of 16S rRNA gene sequences. Multilocus sequence analysis including gyrB, recA and rpoB genes further confirmed that strain TPS16T represented a distinct branch within the family Nocardiopsaceae. The predominant menaquinones were MK-11(H2), MK-10(H2), MK-11(H4) and MK-10(H4), while the major fatty acids were found to be iso-C16 : 0, anteiso-C17 : 0, iso-C15 : 0 and C18 : 1ω9c. Genome sequencing revealed genome sizes of approximately 6 Mb and G+C contents of 73.8 mol%. A new genus, Marinitenerispora gen. nov., is proposed within the family Nocardiopsaceae based on polyphasic data and the type species is Marinitenerispora sediminis gen. nov., sp. nov. The type strain is TPS16T (=DSM 46825T=TBRC 5138T).
    Matched MeSH terms: Vitamin K 2
  11. Kubas MA, Shabaruddin FH, Mazlan-Kepli W, Jagan N, Mohamed S, Mohamed Nazar NI, et al.
    J Pharm Bioallied Sci, 2020 Nov;12(Suppl 2):S781-S786.
    PMID: 33828378 DOI: 10.4103/jpbs.JPBS_381_19
    Introduction: Non-vitamin K antagonist oral anticoagulants (NOACs), such as dabigatran and rivaroxaban, are now available for stroke prevention in patients with atrial fibrillation (AF) and are often clinically preferred over vitamin K antagonists (VKAs), such as warfarin. Data describing adherence and persistence to NOACs in real-life clinical practice in Malaysia are scarce. This study aimed to assess adherence and persistence to NOACs in patients with AF in two tertiary-care referral centers: Hospital Kuala Lumpur (HKL) and Hospital Serdang (HSDG).

    Materials and Methods: This was a retrospective cohort study that included all patients with AF who were treated with NOACs (dabigatran or rivaroxaban) in HKL and HSDG. Data were obtained from medical records and pharmacy databases. Adherence was assessed using proportion of days covered (PDC) over a 1-year duration. High adherence was defined as PDC ≥80%. A gap of >60 days between two consecutive refills was used to define non-persistence.

    Result: There were 281 patients who met the inclusion criteria, with 54.1% (n = 152) male. There were 75.1% (n = 211) patients on dabigatran and others on rivaroxaban. Only 66.9% (n = 188) of patients achieved high adherence with PDC ≥80% and 69.8% (n = 196) were persistence with >60-day gap over 12 months. Adherence and persistence were both influenced by treatment center, whereas polypharmacy only influenced adherence.

    Conclusion: Overall adherence and persistence to NOACs were suboptimal and varied between treatment centers, potentially due to institution-specific administrative and clinical practice differences. Clinical care and outcomes can potentially be optimized by identifying factors affecting adherence and persistence and by implementing interventions to improving them.

    Matched MeSH terms: Vitamin K
  12. Neoh KK, Tang ASN, Looi I, Anita BM
    Case Rep Nephrol, 2020;2020:8828864.
    PMID: 33294240 DOI: 10.1155/2020/8828864
    We report a case of a 21-year-old man with underlying nephrotic syndrome (NS) secondary to minimal change disease, who developed an ischemic stroke with left hemiparesis. He received intravenous thrombolysis followed by a mechanical thrombectomy. After mechanical thrombectomy, he developed acute kidney injury which subsequently required haemodialysis. Further workup revealed that he had concomitant antiphospholipid syndrome (APS) and NS. He was started on vitamin K antagonist anticoagulant. This case report illustrates the importance of workup in identifying causes of ischemic stroke in a young patient.
    Matched MeSH terms: Vitamin K
  13. Raja, Lexshimi R.G., Oranye, N.O., Ho, S.E., Zuraida, J., Zulkifli, S.Z.
    MyJurnal
    The Use of Complementary and alternative medicine (CAM) is a common phenomenon among women with breast cancer in Malaysia. This study examines the prevalence, types, influencing factors and source of information regarding CAM among women with breast cancer, using a cross sectional research design. A purposive sampling was used to recruit 103 women with breast cancer who were attending follow up care at the Radiotherapy and Oncology unit of Universiti Kebangsaan Malaysia Medical Centre. Data was gathered through the use of self–administered questionnaires. Ninety one women identified themselves as CAM users while twelve were non users. Among the CAM users, 57(62.6%) were Malays, 27(29.7%) Chinese and 7(7.7%) Indians. The common types of CAM used were vitamins, nutritional supplements and traditional medicines (TM). CAM was used more frequently upon diagnosis (63.7%) and after completion of conventional treatment (97.8%). With regard to decision-making, most of the women (62.6%) did not make the decision to use CAM and were mostly influenced by their husband and mother (67%). Mother (71.4%), husband (67%), and relatives (56%) were the main sources of information and all values showed significant association with CAM use (p
    Matched MeSH terms: Vitamin K
  14. Sadu Singh BK, Narayanan SS, Khor BH, Sahathevan S, Abdul Gafor AH, Fiaccadori E, et al.
    Front Pharmacol, 2020;11:506.
    PMID: 32410990 DOI: 10.3389/fphar.2020.00506
    Lipid emulsions (LEs), an integral component in parenteral nutrition (PN) feeding, have shifted from the primary aim of delivering non-protein calories and essential fatty acids to defined therapeutic outcomes such as reducing inflammation, and improving metabolic and clinical outcomes. Use of LEs in PN for surgical and critically ill patients is particularly well established, and there is enough literature assigning therapeutic and adverse effects to specific LEs. This narrative review contrarily puts into perspective the fatty acid compositional (FAC) nature of LE formulations, and discusses clinical applications and outcomes according to the biological function and structural functionality of fatty acids and co-factors such as phytosterols, α-tocopherol, emulsifiers and vitamin K. In addition to soybean oil-based LEs, this review covers clinical studies using the alternate LEs that incorporates physical mixtures combining medium- and long-chain triglycerides or structured triglycerides or the unusual olive oil or fish oil. The Jaded score was applied to assess the quality of these studies, and we report outcomes categorized as per immuno-inflammatory, nutritional, clinical, and cellular level FAC changes. It appears that the FAC nature of LEs is the primary determinant of desired clinical outcomes, and we conclude that one type of LE alone cannot be uniformly applied to patient care.
    Matched MeSH terms: Vitamin K
  15. Ser HL, Zainal N, Palanisamy UD, Goh BH, Yin WF, Chan KG, et al.
    Antonie Van Leeuwenhoek, 2015 Jun;107(6):1369-78.
    PMID: 25863667 DOI: 10.1007/s10482-015-0431-5
    A novel Streptomyces, strain MUSC 26(T), was isolated from mangrove soil at Tanjung Lumpur, Malaysia. The bacterium was observed to be Gram-positive and to form grayish yellow aerial and substrate mycelium on ISP 7 agar. A polyphasic approach was used to study the taxonomy of strain MUSC 26(T), which shows a range of phylogenetic and chemotaxonomic properties consistent with those of the members of the genus Streptomyces. The cell wall peptidoglycan was determined to contain LL-diaminopimelic acid. The predominant menaquinones were identified as MK-9 (H8) and MK-9(H6). The polar lipids detected were identified as diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylmethylethanolamine and hydroxyphosphatidylmethylethanolamine. The predominant cellular fatty acids (>10.0 %) were identified as anteiso-C15:0 (31.4 %), iso-C16:0 (16.3 %), iso-C15:0 (13.9 %) and anteiso-C17:0 (12.6 %). The cell wall sugars were found to be galactose, glucose, mannose, ribose and rhamnose. These results suggest that MUSC 26(T) should be placed within the genus Streptomyces. Phylogenetic analysis indicated that closely related strains include Streptomyces qinglanensis 172205(T) (96.5 % sequence similarity), S. sodiiphilus YIM 80305(T) (96.5 %) and S. rimosus subsp. rimosus ATCC 10970(T) (96.4 %). DNA-DNA relatedness values between MUSC 26(T) and closely related type strains ranged from 17.0 ± 2.2 to 33.2 ± 5.3 %. Comparison of BOX-PCR fingerprints indicated MUSC 26(T) presents a unique DNA profile. The DNA G+C content was determined to be 74.6 mol%. Based on this polyphasic study of MUSC 26(T), it is concluded that this strain represents a novel species, for which the name Streptomyces gilvigriseus sp. nov. is proposed. The type strain is MUSC 26(T) (=DSMZ 42173(T) = MCCC 1K00504(T)).
    Matched MeSH terms: Vitamin K 2/analysis
  16. Teh LK, Langmia IM, Fazleen Haslinda MH, Ngow HA, Roziah MJ, Harun R, et al.
    J Clin Pharm Ther, 2012 Apr;37(2):232-6.
    PMID: 21507031 DOI: 10.1111/j.1365-2710.2011.01262.x
    Testing for cytochrome P450-2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) variant alleles is recommended by the FDA for dosing of warfarin. However, dose prediction models derived from data obtained in one population may not be applicable to another. We therefore studied the impact of genetic polymorphisms of CYP2C9 and VKORC1 on warfarin dose requirement in Malaysia.
    Matched MeSH terms: Vitamin K Epoxide Reductases
  17. 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: Vitamin K Epoxide Reductases
  18. Lee SC, Ng SS, Oldenburg J, Chong PY, Rost S, Guo JY, et al.
    Clin. Pharmacol. Ther., 2006 Mar;79(3):197-205.
    PMID: 16513444
    Chinese and Malay subjects have been reported to require less maintenance warfarin than Indians that could not be accounted for by cytochrome P450 (CYP) 2C9 variants. Vitamin K epoxide reductase complex 1 (VKORC1) is the target enzyme of warfarin, and VKORC1 intronic variants and haplotypes have recently been shown to influence VKORC1 activity and warfarin requirements.
    Matched MeSH terms: Vitamin K Epoxide Reductases
  19. Gan GG, Phipps ME, Lee MM, Lu LS, Subramaniam RY, Bee PC, et al.
    Ann Hematol, 2011 Jun;90(6):635-41.
    PMID: 21110192 DOI: 10.1007/s00277-010-1119-6
    Within the Asian populations, Indian patients had been reported to require higher warfarin dose compared with the Chinese and Malay patients, and this could not entirely be explained by cytochrome P450 (CYP)2C9 gene variants. Genetic variants of vitamin K epoxide oxidase reductase complex subunit 1 (VKORC1) has been well established as one of key determinants in the different responses of warfarin amongst patients. Adult patients who attended an anticoagulation clinic with stable INR were recruited. VKORC1 and CYP2C9 genotype were sequenced, and clinical characteristics were assessed. A total of 91 Malays, 96 Chinese, and 46 Indian patients were recruited. The mean age was 55 years and 51.5% were males. The mean dose of warfarin for all patients was 3.7 mg, and the mean daily dose of warfarin was significantly higher in Indians compared with the Chinese and Malay patients, 4.9 versus 3.5 and 3.3 mg, respectively (p 
    Matched MeSH terms: Vitamin K Epoxide Reductases
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