MyMedR

Displaying all 10 publications

Abstract:

Sort:

Fulltext Differential effects of minified and magnified mirror visual feedback on the underlying misperception of hand size

Perera AT, Tan JT, Mu PS, Newport R

Atten Percept Psychophys, 2021 Jul;83(5):2281-2290.
PMID: 33754299 DOI: 10.3758/s13414-021-02262-9

Perception of the size of body parts, for instance the hand, has been shown to be distorted in healthy participants, with over- and underestimations of width and length, respectively. Illusory manipulations of body shape and size have highlighted the flexibility of the body representation and have also been found to update immediate perceptions of body size and surrounding objects. Here, we examined whether underlying misperceptions of hand width and length can be modified through exposure to illusory changes in hand size using a mirror visual feedback (MVF) paradigm. While questionnaire responses indicated subjective susceptibility to both magnified and minified manipulations, objective hand size estimates only showed significant differences following exposure to minifying mirrors. These variations might reflect differences in the way that stored representations are accessed or updated in response to size manipulations. Secondly, the findings further reinforce differences between subjective and objective outcomes of illusions on subsequent body perception.
Fulltext Paraquat poisoning: experience in Hospital Taiping (year 2008 - october 2011)

Tan JT, Letchuman Ramanathan G, Choy MP, Leela R, Lim BK

Med J Malaysia, 2013 Oct;68(5):384-8.
PMID: 24632866 MyJurnal

INTRODUCTION: Paraquat is a quaternary nitrogen herbicide which is highly toxic to human. Death is usually from respiratory failure and may occur within days up to a month after exposure. It is easily available and commonly abused to commit suicide.

METHODOLOGY: This is a retrospective study describing the demographic characteristics, clinical features and outcomes of paraquat poisoning cases admitted to Hospital Taiping from 1st January 2008 to 30th October 2011. Medical records of 79 patients were reviewed.

RESULT: Majority were of the Indian ethnicity (72.2%) followed by Chinese (13.9%) and Malay (10.1%). Majority was male (73.4%) and between 20 to 29 years old (34.2%). The median age of the patients was 30 years old. The mean length of stay was 6.2 days. Most exposures were intentional (69.6%) and presented to the hospital early at less than 6 hours after exposure (72.2%). Patients with positive urine paraquat result had significantly higher mortality rate compared to patients with negative results (47.4% vs 15.2% respectively). We found that neither hemofiltration nor immunosuppressive therapies help to improve survival.

CONCLUSION: The non-survivor characteristics of patients with paraquat poisoning are intentional exposure, delay from exposure to hospital admission, urine paraquat positivity and manifestation of respiratory failure. The demographic characteristics, reasons for exposure and mortality rate are similar to previous reports. Urine paraquat may be used to assess severity of the exposure as well as prognosis. Hemofiltration and immunosuppression therapy do not improve patients' survival and paraquat remains a lethal killer.
Fulltext Comparison of PCR-based genotyping methods for hepatitis B virus

Lim CK, Tan JT, Ravichandran A, Chan YC, Ton SH

Malays J Pathol, 2007 Dec;29(2):79-90.
PMID: 19108399 MyJurnal

Hepatitis B virus (HBV) is classified into eight genotypes (A to H). In this study, three genotyping methods were compared for their sensitivity and accuracy, namely PCR-RFLP on the S region, PCR-RFLP on the pre-S region and nested PCR with type specific primers. Sixty HBV samples from infected sera were genotyped. The nested PCR with type specific primers was found to be the most sensitive and produced substantial numbers of co-infections by genotypes B and C. The sensitivities for both PCR-RFLP methods were lower and did not reveal co-infections. Generally, the three methods produced consistent genotyping results in samples infected by single genotypes but for co-infections by genotypes B and C, the two PCR-RFLP methods yielded only single genotypic results. For the cases of single genotypic infections, genotypes ascertained by sequencing were in concordance across all three methods. However, when co-infections occurred, PCR analysis on clones revealed only single genotypic infections.
ACQUIRED HAEMOPHILIA A

Koh EJ, Tan JT, Amalina Manan NN, Hor KY, Teh ZY, Chin ML

J Ayub Med Coll Abbottabad, 2023;35(4):690-692.
PMID: 38406963

Acquired haemophilia A (AHA) is a rare disease believed to be caused by spontaneous inhibition of clotting Factor VIII by autoantibodies. This is in contrast to the more common congenital haemophilias which are largely due to an absolute deficiency in coagulation factors. It has a prevalence of approximately one per million per year. However, this figure may be underestimated because there are many undocumented cases due to a lack of recognition. Patients who develop this disease may present with catastrophic bleeding despite having no previous bleeding history. In this study, we report a case of acquired Haemophilia A presenting with spontaneous unprovoked bruising and discuss the approach to diagnosis and how to alert the clinician to suspect this potentially rare but devastating disease.
Correlations of HBV genotypes, mutations affecting HBeAg expression and HBeAg/ anti-HBe status in HBV carriers

Lim CK, Tan JT, Khoo JB, Ravichandran A, Low HM, Chan YC, et al.

Int J Med Sci, 2006;3(1):14-20.
PMID: 16421626

This study was carried out to determine the effects of hepatitis B virus genotypes, core promoter mutations (A1762G1764-->T1762A1764) as well as precore stop codon mutations (TGG-->TAG) on HBeAg expression and HBeAg/ anti-HBe status. Study was also performed on the effects of codon 15 variants (C1858/ T1858) on the predisposition of precore stop codon mutations (TGG-->TAG). A total of 77 sera samples were analyzed. Fifty one samples were successfully genotyped of which the predominant genotype was genotype B (29/ 51, 56.9 %), followed by genotype C (16/ 51, 31.4 %). Co-infections by genotypes B and C were observed in four samples (7.8 %). To a lesser degree, genotypes D and E (2.0 % each) were also observed. For core promoter mutations, the prevalence was 68.8 % (53/ 77) for A1762G1764 wild-type and 14.3 % (11/ 77) for T1762A1764 mutant while 9.1 % (7/ 77) was co-infected by both strains. The prevalence of codon 15 variants was found to be 42.9 % (33/ 77) for T1858 variant and 16.9 % (13/ 77) for C1858 variant. No TAG mutation was found. In our study, no associations were found between genotypes (B and C) and core promoter mutations as well as codon 15 variants. Also no correlation was observed between HBeAg/ anti-HBe status with genotypes (B and C) and core promoter mutations.
Fulltext Impact of timely BCR-ABL1 monitoring before allogeneic stem cell transplantation among patients with BCR-ABL1-positive B-acute lymphoblastic leukemia

Chong SL, Asnawi AWA, Leong TS, Tan JT, Law KB, Hon SL, et al.

Blood Res, 2021 Sep 30;56(3):175-183.
PMID: 34462403 DOI: 10.5045/br.2021.2021045

Background: With the emergence of tyrosine kinase inhibitors and the incorporation of stringent measurable residual disease (MRD) monitoring, risk stratification for BCR-ABL1-positive acute lymphoblastic leukemia (ALL) patients has changed significantly. However, whether this monitoring can replace conventional risk factors in determining whether patients need allogeneic stem cell transplantation is still unclear. This study aimed to determine the impact of BCR-ABL1 monitoring on the outcome of patients with BCR-ABL1-positive ALL after allogeneic stem cell transplantation.
Methods: We retrospectively analyzed the survival outcome of patients with BCR-ABL1-positive ALL based on the quantification of BCR-ABL1 at 3 timepoints: the end of induction (timepoint 1), post-consolidation week 16 (timepoint 2), and the end of treatment for patients who were either transplant-eligible or non-transplant eligible (timepoint 3).
Results: From 2006 to 2018, a total of 96 patients newly diagnosed with BCR-ABL1-positive ALL were treated with chemotherapy and tyrosine kinase inhibitors. Thirty-eight (41.3%) patients achieved complete remission, and 33 patients underwent allogeneic stem cell transplantation. Our data showed that pre-transplant MRD monitoring by real-time quantitative polymerase chain reaction had the highest correlation with survival in patients with BCR-ABL1-positive ALL, especially for those who underwent allogeneic stem cell transplantation.
Conclusion: Patients without MRD pre-transplantation had superior survival compared with those who had MRD, and they had excellent long-term outcomes after allogeneic stem cell transplantation.
Fulltext Polymorphisms at newly identified lipid-associated loci are associated with blood lipids and cardiovascular disease in an Asian Malay population

Tai ES, Sim XL, Ong TH, Wong TY, Saw SM, Aung T, et al.

J Lipid Res, 2009 Mar;50(3):514-520.
PMID: 18987386 DOI: 10.1194/jlr.M800456-JLR200

We conducted a cross-sectional study of Malay participants aged 40-80 years (n = 2,932) to examine the associations between polymorphisms at newly identified, lipid-associated loci with blood lipid levels and prevalent cardiovascular disease (CVD) in a Malay population in Asia. A polymorphism adjacent to the TRIB1 locus (rs17321515) was associated with elevated total cholesterol and LDL-cholesterol (LDL-C) after adjustment for age and sex (both P values <0.007) and with increased risk of coronary heart disease and CVD [odds ratio (OR) 1.23, 95% confidence interval (95% CI) 1.03-1.46; and OR 1.2, 95% CI 1.02-1.42, respectively] under an additive model of inheritance. In addition, using recessive models of inheritance, polymorphisms on chromosome 19 adjacent to the CILP2 and PBX4 loci (rs16996148) and on chromosome 1 at the GALNT2 locus (rs4846914) were associated with elevated HDL-C (P = 0.005) and lower LDL-C (P = 0.048), respectively. Although novel, the former is consistent with the association between this polymorphism and lower blood triglycerides observed in the initial studies conducted in populations of European ancestry. Neither showed statistically significant association with CVD. These observations should form the basis of further investigation to identify the causative polymorphisms at this locus, and also to understand the mechanistic roles that this protein may play in lipoprotein metabolism in Asians and other populations.
Polymorphisms identified through genome-wide association studies and their associations with type 2 diabetes in Chinese, Malays, and Asian-Indians in Singapore

Tan JT, Ng DP, Nurbaya S, Ye S, Lim XL, Leong H, et al.

J Clin Endocrinol Metab, 2010 Jan;95(1):390-7.
PMID: 19892838 DOI: 10.1210/jc.2009-0688

CONTEXT:
Novel type 2 diabetes mellitus (T2DM) susceptibility loci, identified through genome-wide association studies (GWAS), have been replicated in many European and Japanese populations. However, the association in other East Asian populations is less well characterized.

OBJECTIVE:
To examine the effects of SNPs in CDKAL1, CDKN2A/B, IGF2BP2, HHEX, SLC30A8, PKN2, LOC387761, and KCNQ1 on risk of T2DM in Chinese, Malays, and Asian-Indians in Singapore.

DESIGN:
We genotyped these candidate single-nucleotide polymorphisms (SNPs) in subjects from three major ethnic groups in Asia, namely, the Chinese (2196 controls and 1541 cases), Malays (2257 controls and 1076 cases), and Asian-Indians (364 controls and 246 cases). We also performed a metaanalysis of our results with published studies in East Asians.

RESULTS:
In Chinese, SNPs in CDKAL1 [odds ratio (OR) = 1.19; P = 2 x 10(-4)], HHEX (OR = 1.15; P = 0.013), and KCNQ1 (OR = 1.21; P = 3 x 10(-4)) were significantly associated with T2DM. Among Malays, SNPs in CDKN2A/B (OR = 1.22; P = 3.7 x 10(-4)), HHEX (OR = 1.12; P = 0.044), SLC30A8 (OR = 1.12; P = 0.037), and KCNQ1 (OR = 1.19-1.25; P = 0.003-2.5 x 10(-4)) showed significant association with T2DM. The combined analysis of the three ethnic groups revealed significant associations between SNPs in CDKAL1 (OR = 1.13; P = 3 x 10(-4)), CDKN2A/B (OR = 1.16; P = 9 x 10(-5)), HHEX (OR = 1.14; P = 6 x 10(-4)), and KCNQ1 (OR = 1.16-1.20; P = 3 x 10(-4) to 3 x 10(-6)) with T2DM. SLC30A8 (OR = 1.06; P = 0.039) showed association only after adjustment for gender and body mass index. Metaanalysis with data from other East Asian populations showed similar effect sizes to those observed in populations of European ancestry.

CONCLUSIONS:
SNPs at T2DM susceptibility loci identified through GWAS in populations of European ancestry show similar effects in Asian populations. Failure to detect these effects across different populations may be due to issues of power owing to limited sample size, lower minor allele frequency, or differences in genetic effect sizes.
A randomized double blind control trial comparing filgrastim and pegfilgrastim in cyclophosphamide peripheral blood hematopoietic stem cell mobilization

Kuan JW, Su AT, Wong SP, Sim XY, Toh SG, Ong TC, et al.

Transfus Apher Sci, 2015 Oct;53(2):196-204.
PMID: 25910537 DOI: 10.1016/j.transci.2015.03.017

There are few randomized trials comparing filgrastim and pegfilgrastim in peripheral blood stem cell mobilization (PBSCM). None of the trials studied the effects of the timing of pegfilgrastim administration on the outcomes of mobilization. We conducted a randomized triple blind control trial comparing the outcomes of filgrastim 5 µg/kg daily from day 3 onwards, 'early' pegfilgrastim 6 mg on day 3 and 'delayed' pegfilgrastim 6 mg on day 7 in cyclophosphamide PBSCM in patients with no previous history of mobilization. Peripheral blood (PB) CD34+ cell count was checked on day 8 and day 11 onward. Apheresis was started when PB CD34+ ≥ 10/µl from day 11 onward. The primary outcome was the successful mobilization rate, defined as cumulative collection of ≥2 × 10(6)/kg CD34+ cells in three or less apheresis. The secondary outcomes were the day of neutrophil and platelet engraftment post transplantation. There were 156 patients randomized and 134 patients' data analyzed. Pegfilgrastim 6 mg day 7 produced highest percentage of successful mobilization, 34 out of 48 (70.8%) analyzed patients, followed by daily filgrastim, 28 out of 44 (63.6%) and day 3 pegfilgrastim, 20 out of 42 (47.6%) (p = 0.075). Pegfilgrastim day 7 and daily filgrastim reported 1.48 (p = 0.014) and 1.49 (p = 0.013) times higher successful mobilization rate respectively as compared to pegfilgrastim day 3 after adjusting for disease, gender and exposure to myelotoxic agent. Multiple myeloma patients were three times more likely to achieve successful mobilization as compared to acute leukemia or lymphoma patients. Pegfilgrastim avoided the overshoot of white cells compared to filgrastim. There was no difference in the duration of both white cells and platelet recovery post transplantation between the three interventional arms.
The epidemiology and clinical characteristics of myeloproliferative neoplasms in Malaysia

Yap YY, Law KB, Sathar J, Lau NS, Goh AS, Chew TK, et al.

Exp Hematol Oncol, 2018;7:31.
PMID: 30564475 DOI: 10.1186/s40164-018-0124-7

Background: The evolution of molecular studies in myeloproliferative neoplasms (MPN) has enlightened us the understanding of this complex disease consisting of polycythaemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The epidemiology is well described in the western world but not in Asian countries like Malaysia.
Materials and methods: This retrospective national registry of MPN was conducted from year 2009 to 2015 in Malaysia.
Results: A total of 1010 patients were registered over a period of 5 years. The mean age was 54 years with male predominance. The ethnic distribution revealed that Chinese had a relatively high weighted incidence proportion (43.2%), followed by Indian (23.8%), Malay (15.8%) and other ethnic groups (17.2%). The types of MPN reported were 40.4% of ET (n = 408), 38.1% of PV (n = 385), 9.2% of PMF (n = 93), 3.1% of hypereosinophilic syndrome (HES) (n = 31) and 7.9% of unclassifiable MPN (MPN-U) (n = 80). Splenomegaly was only palpable clinically in 32.2% of patients. The positive JAK2 V617F mutation was present in 644 patients with 46.6% in PV, 36.0% in ET, 9.0% in PMF, and 7.4% in MPN-U, and had significantly lower haemoglobin (p