MyMedR

Dimethoate and atrazine retention from aqueous solution by nanofiltration membranes

Ahmad AL, Tan LS, Shukor SR

J Hazard Mater, 2008 Feb 28;151(1):71-7.

In order to produce sufficient food supply for the ever-increasing human population, pesticides usage is indispensable in the agriculture sector to control crop losses. However, the effect of pesticides on the environment is very complex as undesirable transfers occur continually among different environmental sections. This eventually leads to contamination of drinking water source especially for rivers located near active agriculture practices. This paper studied the application of nanofiltration membrane in the removal of dimethoate and atrazine in aqueous solution. Dimethoate was selected as the subject of study since it is being listed as one of the pesticides in guidelines for drinking water by World Health Organization. Nevertheless, data on effectiveness of dimethoate rejection using membranes has not been found so far. Meanwhile, atrazine is classified as one of the most commonly used pesticides in Malaysia. Separation was done using a small batch-type membrane separation cell with integrated magnetic stirrer while concentration of dimethoate and atrazine in aqueous solution was analyzed using high performance liquid chromatography (HPLC). Four nanofiltration membranes NF90, NF200, NF270 and DK were tested for their respective performance to separate dimethoate and atrazine. Of all four membranes, NF90 showed the best performance in retention of dimethoate and atrazine in water.

Fulltext Immunological profiles of immune restoration disease presenting as mycobacterial lymphadenitis and cryptococcal meningitis

Tan DB, Yong YK, Tan HY, Kamarulzaman A, Tan LH, Lim A, et al.

HIV Med, 2008 May;9(5):307-16.

PMID: 18400078 DOI: 10.1111/j.1468-1293.2008.00565.x

A proportion of HIV patients beginning antiretroviral therapy (ART) develop immune restoration disease (IRD). Immunological characteristics of IRD were investigated in a cohort of HIV patients beginning therapy in Kuala Lumpur, Malaysia.

The role of pH in nanofiltration of atrazine and dimethoate from aqueous solution

Ahmad AL, Tan LS, Abd Shukor SR

J Hazard Mater, 2008 Jun 15;154(1-3):633-8.

PMID: 18055106

This study examined the performance of nanofiltration membranes to retain atrazine and dimethoate in aqueous solution under different pH conditions. Four nanofiltration membranes, NF90, NF200, NF270 and DK are selected to be examined. The operating pressure, feed pesticide and stirring rate were kept constant at 6x10(5) Pa, 10 mg/L and 1000 rpm. It was found that increasing the solution's pH increased atrazine and dimethoate rejection but reduced the permeate flux performance for NF200, NF270 and DK. However, NF90 showed somewhat consistent performance in both rejection and permeate flux regardless of the solution's pH. NF90 maintained above 90% of atrazine rejection and approximately 80% of dimethoate rejection regardless of the changes in solution's pH. Thus, NF90 is deemed the more suitable nanofiltration membrane for atrazine and dimethoate retention from aqueous solution compared to NF200, NF270 and DK.

Fulltext Riding on the crest of electronic publishing wave

Kadri N, Tan L, Ng Kh

Biomed Imaging Interv J, 2009 Jan;5(1):e1.

PMID: 21611022 MyJurnal DOI: 10.2349/biij.5.1.e1

Acute retinal necrosis by cytomegalovirus in an immunocompetent adult: case report and review of the literature

Tajunisah I, Reddy SC, Tan LH

Int Ophthalmol, 2009 Apr;29(2):85-90.

PMID: 18026692

A rare case of acute retinal necrosis caused by cytomegalovirus in an immunocompetent adult, diagnosed by polymerase chain reaction of vitreous aspirate, with good visual outcome after intravitreal and intravenous ganciclovir and oral prednisolone therapy, is reported. A 50-year-old healthy lady presented with redness and diminution of vision in her right eye of 10 days duration. She had anterior chamber inflammation, marked vitritis, and anterior retinal necrosis in the right eye. Blood and other investigations did not reveal any infectious diseases and HIV testing was negative. The retinal lesions and panuveitis resolved with treatment. Two months later she developed retinal detachment which was treated successfully. The best-corrected vision was 6/12 in the right eye. Seven cases of cytomegalovirus ocular infection in immunocompetent healthy adults, reported in the literature, were reviewed. The different presentations of this disease and the importance of suspecting this causative agent are highlighted.

Fulltext Isolation of Mycoplasma hyosynoviae from pneumonic lung of swine

Dahlia H, Tan LJ, Zarrahimah Z, Maria J

Trop Biomed, 2009 Dec;26(3):341-5.

PMID: 20237449 MyJurnal

The isolation of Mycoplasma hyosynoviae from a piglet with severe pneumonia is described. This is the first report of M. hyosynoviae isolation in the country. The lung sample where the isolation was made was severely consolidated, suppurative and pleurisy. The pathogenicity of the M. hyosynoviae isolated has yet to be determined.

WITHDRAWN: Preliminary investigation on Mycoplasma maculosum isolated from chickens

Mohd-Zain Z, Tan LJ

Res Vet Sci, 2010 Nov 09.

PMID: 21067786

This article has been withdrawn at the request of the authors. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Fulltext Unusual manifestation of cutaneous toxoplasmosis in a HIV-positive patient

Fong MY, Wong KT, Rohela M, Tan LH, Adeeba K, Lee YY, et al.

Trop Biomed, 2010 Dec;27(3):447-50.

PMID: 21399585 MyJurnal

We report a case of unusual cutaneous toxoplasmosis manifestation in a HIV-positive patient. He presented with hard and painful nodular lesions on the arms, hands and chest. Serology tests for anti-Toxoplasma antibody were negative. However, histopathologic examination of the lesion revealed foci of macrophages containing crescent-shaped organisms resembling the zoites of the protozoan parasite Toxoplasma gondii. Ultrastructure examination under electron microscopy and PCR confirmed the organism as T. gondii.

Fulltext Awareness of eye complications and prevalence of retinopathy in the first visit to eye clinic among type 2 diabetic patients

Tajunisah I, Wong P, Tan L, Rokiah P, Reddy S

Int J Ophthalmol, 2011;4(5):519-24.

PMID: 22553714 DOI: 10.3980/j.issn.2222-3959.2011.05.12

AIM: To assess the awareness of eye complications and the prevalence of retinopathy, in the first visit to eye clinic, among type 2 diabetic patients attending a tertiary medical centre in Kuala Lumpur, Malaysia.
METHODS: An investigator-administered questionnaire was given to 137 patients with diabetes undergoing first time eye screening in the eye clinic. This was followed by a detailed fundus examination by a senior ophthalmologist to assess for presence of retinopathy.
RESULTS: Almost 86% of respondents were aware of diabetic eye complications, especially in patients who had achieved tertiary educational level (96.3%). The majority of the patients (78.8%) were referred by their physicians and only 20.4% came on their own initiative. Many of the patients (43.8%) did not know how frequent they should go for an eye check-up and 72.3% did not know what treatments were available. Lack of understanding on diabetic eye diseases (68.6%) was the main barrier for most patients for not coming for eye screening earlier. Despite a high level of awareness, only 21.9% had recorded HbA1c level of <6.5% while 31.4% were under the erroneous assumption of having a good blood sugar control. A total of 29.2% had diabetic retinopathy in their first visit eye testing.
CONCLUSION: In the present study, 29.2% of type 2 diabetic patients had retinopathy in their first time eye testing. Although the awareness of diabetic eye complications was high among first time eye screening patients, the appropriate eye care-seeking behavior was comparatively less and should be rectified to prevent the rise of this sight threatening eye disease.
KEYWORDS: awa-reness; diabetic retinopathy; eye complications; eye screening
Study site: Eye clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia

Fulltext Penicilliosis in lupus patients presenting with unresolved fever: a report of 2 cases and literature review

Chong YB, Tan LP, Robinson S, Lim SK, Ng KP, Keng TC, et al.

Trop Biomed, 2012 Jun;29(2):270-6.

PMID: 22735849 MyJurnal

Penicilliosis is a rare occurrence among non human immunodeficiency virus (HIV) infected patients. We report here two cases of Penicillium marneffei infection in patients with systemic lupus erythematosus (SLE). Both patients had a recent flare of lupus and were on immunosuppressive drugs when they presented with prolonged fever without an obvious foci of infection, unresponsive to broad-spectrum antibiotics. They were leucopaenic upon admission, with rapid deterioration during the course of the illness. Diagnosis of penicilliosis via fungal isolation from blood culture was delayed resulting in the late initiation of antifungal agents. While both patients ultimately recovered, the delay in diagnosis led to a prolonged hospital stay with increased morbidity. Clinicians should be aware of this uncommon but emerging fungal pathogen in SLE patients and maintain a high index of suspicion in diagnosing this potentially fatal but treatable disease.

Quantification of diffusion tensor imaging in normal white matter maturation of early childhood using an automated processing pipeline

Loh KB, Ramli N, Tan LK, Roziah M, Rahmat K, Ariffin H

Eur Radiol, 2012 Jul;22(7):1413-26.

PMID: 22434420 DOI: 10.1007/s00330-012-2396-3

OBJECTIVES: The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas.

METHODS: Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction.

RESULTS: DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued.

CONCLUSION: DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data.

KEY POINTS: Diffusion tensor imaging outperforms conventional MRI in depicting white matter maturation. • DTI will become an important clinical tool for diagnosing paediatric neurological diseases. • DTI appears especially helpful for developmental abnormalities, tumours and white matter disease. • An automated processing pipeline assists quantitative analysis of high throughput DTI data.

Pneumocystis jirovecii pneumonia 13 years post renal transplant following a recurrent cytomegalovirus infection

Muhammad Iqbal AH, Lim SK, Ng KP, Tan LP, Chong YB, Keng TC

Transpl Infect Dis, 2012 Aug;14(4):E23-6.

PMID: 22551151 DOI: 10.1111/j.1399-3062.2012.00738.x

Pneumocystis jirovecii (formerly Pneumocystis carinii) pneumonia (PCP) is a rare but serious infection that usually occurs within a year after solid organ transplantation. PCP may occur after 1 year post transplantation, but the rate is reported to be very low. Studies have shown an association between cytomegalovirus (CMV) infection in solid organ transplant patients and an increased risk of opportunistic infection. This increased risk is thought to be a result of the immunomodulatory effects of the CMV infection. We present a case of PCP infection occurring 13 years after a renal transplantation. This occurred following a recurrent CMV infection while the patient was on low-dose immunosuppressants.

HLA variants rs9271366 and rs9275328 are associated with systemic lupus erythematosus susceptibility in Malays and Chinese

Chai HC, Phipps ME, Othman I, Tan LP, Chua KH

Lupus, 2013 Feb;22(2):198-204.

PMID: 23257407 DOI: 10.1177/0961203312470183

BACKGROUND: Human leukocyte antigen (HLA) antigens and genes have long been reported associated with systemic lupus erythematosus (SLE) susceptibility in many populations. With the advance in technologies such as genome-wide association studies, many newly discovered SLE-associated single-nucleotide polymorphisms (SNPs) have been reported in recent years. These include HLA-DRB1/HLA-DQA1 rs9271366 and HLA-DQB1/HLA-DQA2 rs9275328. Our aim was to investigate these SNPs in a Malaysian SLE cohort.
MATERIALS AND METHODS: SNPs rs9271366 and rs9275328 were screened across 790 Malaysian citizens from three ethnic groups (360 patients and 430 healthy volunteers) by Taqman SNP genotyping assays. Allele and genotyping frequencies, Hardy-Weinberg equilibrium, Fisher's exact test and odds ratio were calculated for each SNP and ethnic group. Linkage disequilibrium and interaction between the two SNPs were also evaluated.
RESULTS: The minor allele G and its homozygous genotype GG of HLA-DRB1/HLA-DQA1 rs9271366 significantly increased the SLE susceptibility in Malaysian patients, including those of Malay and Chinese ethnicity (odds ratio (OR) > 1, p

Fulltext Pilomatrixoma of left shoulder in an elderly female: a case report

Tan L, Ooi C, Chua H, Zulkiflee O

Malays Orthop J, 2013 Jul;7(2):48-50.

PMID: 25722828 MyJurnal DOI: 10.5704/MOJ.1307.005

We report a huge pilomatrixoma of the left shoulder in an elderly female, raising fear of malignancy. Magnetic Resonance Imaging delineated the swelling and wide surgical excision was performed. Post operative recovery was uneventful. Long term follow up is necessary in view of the possibility of recurrence and malignant transformation.

KEY WORDS: Pilomatrixoma, Pilomatricoma, Calcifying Epithelioma of Malherbe, Shoulder, Upper Limb, Elderly, Female.

Improved diagnostic accuracy in differentiating malignant and benign lesions using single-voxel proton MRS of the breast at 3 T MRI

Suppiah S, Rahmat K, Mohd-Shah MN, Azlan CA, Tan LK, Aziz YF, et al.

Clin Radiol, 2013 Sep;68(9):e502-10.

PMID: 23706826 DOI: 10.1016/j.crad.2013.04.002

To investigate the diagnostic accuracy of single-voxel proton magnetic resonance spectroscopy (SV (1)H MRS) by quantifying total choline-containing compounds (tCho) in differentiating malignant from benign lesions, and subsequently, to analyse the relationship of tCho levels in malignant breast lesions with their histopathological subtypes.

Glaucoma severity affects diffusion tensor imaging (DTI) parameters of the optic nerve and optic radiation

Sidek S, Ramli N, Rahmat K, Ramli NM, Abdulrahman F, Tan LK

Eur J Radiol, 2014 Aug;83(8):1437-41.

PMID: 24908588 DOI: 10.1016/j.ejrad.2014.05.014

To evaluate whether MR diffusion tensor imaging (DTI) of the optic nerve and optic radiation in glaucoma patients provides parameters to discriminate between mild and severe glaucoma and to determine whether DTI derived indices correlate with retinal nerve fibre layer (RNFL) thickness.

Fulltext Development of a controlled release of salicylic acid loaded stearic acid-oleic acid nanoparticles in cream for topical delivery

Woo JO, Misran M, Lee PF, Tan LP

ScientificWorldJournal, 2014;2014:205703.

PMID: 24578624 DOI: 10.1155/2014/205703

Lipid nanoparticles are colloidal carrier systems that have extensively been investigated for controlled drug delivery, cosmetic and pharmaceutical applications. In this work, a cost effective stearic acid-oleic acid nanoparticles (SONs) with high loading of salicylic acid, was prepared by melt emulsification method combined with ultrasonication technique. The physicochemical properties, thermal analysis and encapsulation efficiency of SONs were studied. TEM micrographs revealed that incorporation of oleic acid induces the formation of elongated spherical particles. This observation is in agreement with particle size analysis which also showed that the mean particle size of SONs varied with the amount of OA in the mixture but with no effect on their zeta potential values. Differential scanning calorimetry analysis showed that the SONs prepared in this method have lower crystallinity as compared to pure stearic acid. Different amount of oleic acid incorporated gave different degree of perturbation to the crystalline matrix of SONs and hence resulted in lower degrees of crystallinity, thereby improving their encapsulation efficiencies. The optimized SON was further incorporated in cream and its in vitro release study showed a gradual release for 24 hours, denoting the incorporation of salicylic acid in solid matrix of SON and prolonging the in vitro release.

Fulltext The Association Between Bullous Pemphigoid and Neurological Disorders in A Selected Malaysian Population

Kwan Z, Lai YN, Ch'ng CC, Tan AH, Tan LL, Robinson S, et al.

Med J Malaysia, 2015 Apr;70(2):81-5.

PMID: 26162382 MyJurnal

BACKGROUND: An association of bullous pemphigoid with neurological disorders has been reported. The objectives of this study were to review the clinical characteristics of patients with bullous pemphigoid and compare the association between bullous pemphigoid and various neurological disorders and comorbidities.

METHODS: This was a retrospective case-control study involving 43 patients with bullous pemphigoid and 43 age-, sex- and ethnicity-matched controls.

RESULTS: There was a statistically significant association between bullous pemphigoid and neurological disorders [Odds Ratio (OR) = 3.5, 95% Confidence Interval (CI) 1.3 to 9.2, p=0.011 and adjusted OR=3.5, 95% CI 1.2-10.3, p=0.026], in particular for dementia (p=0.002). Although stroke was more common among patients with bullous pemphigoid, this association was not statistically significant with OR of 1.9 (95% CI 0.7 to 5.2) and adjusted OR of 2.1 (95% CI 0.6 to 7.2). Similarly both ischaemic stroke (OR 1.5, 95% CI 0.5 to 4.2) and haemorrhagic stroke (OR 1.5, 95% CI 0.2 to 9.7) were more common. Other neurological disorders more common among patients with bullous pemphigoid were Parkinson's disease and epilepsy. Dyslipidaemia was significantly less common among patients with bullous pemphigoid (OR 0.4, 95% CI 0.1 to 0.9, p=0.033).

CONCLUSION: A combination of an inflammatory process, prothrombotic state and endothelial activation leads to an increased frequency of neurological disorders among patients with bullous pemphigoid. Thus, a holistic approach to patient care, including screening for dementia and control of comorbidities, should be practised as bullous pemphigoid affects more than just the skin.

Motion corrected LV quantification based on 3D modelling for improved functional assessment in cardiac MRI

Liew YM, McLaughlin RA, Chan BT, Abdul Aziz YF, Chee KH, Ung NM, et al.

Phys Med Biol, 2015 Apr 7;60(7):2715-33.

PMID: 25768708 DOI: 10.1088/0031-9155/60/7/2715

Cine MRI is a clinical reference standard for the quantitative assessment of cardiac function, but reproducibility is confounded by motion artefacts. We explore the feasibility of a motion corrected 3D left ventricle (LV) quantification method, incorporating multislice image registration into the 3D model reconstruction, to improve reproducibility of 3D LV functional quantification. Multi-breath-hold short-axis and radial long-axis images were acquired from 10 patients and 10 healthy subjects. The proposed framework reduced misalignment between slices to subpixel accuracy (2.88 to 1.21 mm), and improved interstudy reproducibility for 5 important clinical functional measures, i.e. end-diastolic volume, end-systolic volume, ejection fraction, myocardial mass and 3D-sphericity index, as reflected in a reduction in the sample size required to detect statistically significant cardiac changes: a reduction of 21-66%. Our investigation on the optimum registration parameters, including both cardiac time frames and number of long-axis (LA) slices, suggested that a single time frame is adequate for motion correction whereas integrating more LA slices can improve registration and model reconstruction accuracy for improved functional quantification especially on datasets with severe motion artefacts.

Bisulfite pretreatment changes the structure and properties of oil palm empty fruit bunch to improve enzymatic hydrolysis and bioethanol production

Tan L, Sun W, Li X, Zhao J, Qu Y, Choo YM, et al.

Biotechnol J, 2015 Jun;10(6):915-25.

PMID: 25866127 DOI: 10.1002/biot.201400733

Bisulfite pretreatment is a proven effective method for improving the enzymatic hydrolysis of empty fruit bunch (EFB) from oil palm for bioethanol production. In this study, we set out to determine the changes that occur in the structure and properties of EFB materials and fractions of hemicellulose and lignin during the bisulfite pretreatment process. The results showed that the crystallinity of cellulose in EFB increased after bisulfite pretreatment, whereas the EFB surface was damaged to various degrees. The orderly structure of EFB, which was maintained by hydrogen bonds, was destroyed by bisulfite pretreatment. Bisulfite pretreatment also hydrolyzed the glycosidic bonds of the xylan backbone of hemicellulose, thereby decreasing the molecular weight and shortening the xylan chains. The lignin fractions obtained from EFB and pretreated EFB were typically G-S lignin, and with low content of H units. Meanwhile, de-etherification occurred at the β-O-4 linkage, which was accompanied by polymerization and demethoxylation as a result of bisulfite pretreatment. The adsorption ability of cellulase differed for the various lignin fractions, and the water-soluble lignin fractions had higher adsorption capacity on cellulase than the milled wood lignin. In general, the changes in the structure and properties of EFB provided insight into the benefits of bisulfite pretreatment.

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