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Prevalence and determinants of excessive daytime sleepiness in an Asian multi-ethnic population

Ng TP, Tan WC

Sleep Med, 2005 Nov;6(6):523-9.
PMID: 16271696

BACKGROUND AND PURPOSE: To investigate the prevalence and determinants of daytime sleepiness in an Asian multi-ethnic population. Cross-sectional survey based on a questionnaire in multi-ethnic Asian adult population of Singapore (2.4 million).
PATIENTS AND METHODS: Measured frequency of excessive daytime sleepiness (EDS), socio-demographic status, sleep duration, perceived sleep insufficiency, frequent awakenings, difficulty falling asleep, snoring, breathing pauses, GHQ-12, shift work, solvent exposure at work, substance use, medications, and chronic diseases in random sample of 2,298 adults, aged 20-74 years, representing Chinese, Malays and Indians.
RESULTS: Among the respondents, 10.8% reported usually feeling sleepy in the daytime, and 9.0% were classified as having EDS. Marked ethnic difference was observed, with higher rates of EDS in Malays and Chinese, compared to Indians. Increased risk of EDS was associated with perceived sleep insufficiency; snoring and breathing pauses; shift work and solvent exposure at work; psychiatric morbidity and chronic diseases, particularly chronic rhinitis; and medications with sedating effects.
CONCLUSIONS: Daytime sleepiness is associated with a multiplicity of highly prevalent risk factors in the community, including sleep behavior, breathing-, work- and medically related factors. Significant ethnic differences, which were not explained by these factors, were observed between Chinese, Malays and Indians.
Predominance of amoeboid forms of Blastocystis hominis in isolates from symptomatic patients

Tan TC, Suresh KG

Parasitol Res, 2006 Feb;98(3):189-93.
PMID: 16323025

Blastocystis hominis is one of the most common human parasites that inhabit the intestinal tract. Conflicting reports continue to exist regarding the existence and the functional role of the amoeboid forms in the life cycle of the parasite. The present study investigates the presence of these forms in 20 isolates obtained from ten symptomatic and asymptomatic patients respectively. A total of 10,000 parasite cells per ml from each isolate were inoculated into three culture tubes each containing 3 ml of Jones' medium supplemented with 10% horse serum, incubated at 37 degrees C. The contents were examined daily for 10 days. Irregular and polymorphic amoeboid forms with multiple extended pseudopodia were observed in all isolates from symptomatic patients, while none of the isolates from asymptomatic patients showed the presence of the amoeboid forms. The amoeboid forms were initially noted on day 2 and the percentages increased from 2% to 28%, with peak percentages from day 3 to day 6. Transmission electron microscopy revealed two types of amoeboid forms; one containing a large central vacuole completely filled with tiny electron-dense granules, and the other which revealed multiple small vacuoles within the central body. The cytoplasm contained strands of electron-dense granules resembling rough endoplasmatic reticulum, which is suggestive of active protein synthesis. The surface coat of the amoeboid form surrounding the parasite showed uneven thickness. Acridine orange stained the central body yellow and the periphery orange, indicating activity at the level of nucleic acids. The amoeboid form could either be an indicator of pathogenicity of B. hominis, or the form likely to contribute to pathogenicity and be responsible for the symptoms seen in patients.
Ulcerative colitis in a multiracial Asian country: racial differences and clinical presentation among Malaysian patients

Tan YM, Goh KL

World J Gastroenterol, 2005 Oct 07;11(37):5859-62.
PMID: 16270398

AIM: Inflammatory bowel disease appears to be uncommon among Asians. This study was conducted to determine the prevalence of ulcerative colitis (UC) in Malaysian patients and to establish the spectrum of the disease seen in Malaysian patients. Three major Asian races: Malay, Chinese, and Indian co-exist in Malaysia and we sought to determine if there were any racial differences in the prevalence and presentation of disease. Racial differences for several other gastrointestinal diseases have previously been observed and found to be extremely interesting.
METHODS: Data were obtained retrospectively from a review of the medical records of in- and out-patients with a diagnosis of UC at the University Hospital, Kuala Lumpur between 1985 and 1998.
RESULTS: There were 45 confirmed cases of UC of which 3 were foreigners, who were excluded from analysis. Thirty new cases of UC were diagnosed during the study period. Their mean age at presentation was 33.0+/-10.0 years. The highest prevalence of UC was 17.9/100 000 hospital admissions in the Indians, followed by 11.2/100 000 hospital admissions in the Chinese. The lowest prevalence was 3.7/100 000 hospital admissions in the Malays. The prevalence of UC was significantly higher in the Indians and the Chinese when compared with the Malays with an OR of 4.89 (CI = 2.02-12.24; chi2 = 15.45, P<0.001) and 3.06 (CI = 1.24-7.78; chi2 = 6.30; P = 0.012) respectively. The extent of colonic disease was similar in the Malay and Indian patients. In contrast, distal or left-sided colitis predominated in the Chinese with an OR of 8.17 (95%CI = 1.31-64.87; chi2 = 5.53, P = 0.02). Extraintestinal manifestations were uncommon (11.9%).
CONCLUSION: UC is an uncommon disease in Malaysia, but racial differences exist. The Indians had the highest prevalence of UC with the Chinese demonstrating the least extensive disease.
Contemporary approaches to hyperemesis during pregnancy

Tan PC, Omar SZ

Curr Opin Obstet Gynecol, 2011 Apr;23(2):87-93.
PMID: 21297474 DOI: 10.1097/GCO.0b013e328342d208

PURPOSE OF REVIEW: Nausea and vomiting of pregnancy (NVP) affects 90% of pregnant women and its impact is often underappreciated. Hyperemesis gravidarum, the most severe end of the spectrum, affects 0.5-2% of pregnancies. The pathogenesis of this condition remains obscure and its management has largely been empirical. This review aims to provide an update on advances in pregnancy hyperemesis focusing on papers published within the past 2 years.
RECENT FINDINGS: The cause of hyperemesis is continuing to be elaborated. Recent data attest to the effectiveness of the oral doxylamine-pyridoxine in NVP. Follow-up data of children exposed in early pregnancy to doxylamine-pyridoxine for NVP are reassuring. Evidence is increasing for ginger as an effective herbal remedy for NVP. Metoclopramide is effective in NVP and hyperemesis gravidarum, with a good balance of efficacy and tolerability. A recent large-scale study on first trimester exposure to metoclopramide is reassuring of its safety. Evidence is emerging for the treatment of acid reflux to ameliorate NVP. The role of corticosteroids for hyperemesis gravidarum remains controversial. Transpyloric feeding may be warranted for persistent weight loss, despite optimal antiemetic therapy.
SUMMARY: Women with significant NVP should be identified so that they can be safely and effectively treated.
Magnetic nanoparticle (Fe3O4) impregnated onto tea waste for the removal of nickel(II) from aqueous solution

Panneerselvam P, Morad N, Tan KA

J Hazard Mater, 2011 Feb 15;186(1):160-8.
PMID: 21146294 DOI: 10.1016/j.jhazmat.2010.10.102

The removal of Ni(II) from aqueous solution by magnetic nanoparticles prepared and impregnated onto tea waste (Fe(3)O(4)-TW) from agriculture biomass was investigated. Magnetic nanoparticles (Fe(3)O(4)) were prepared by chemical precipitation of a Fe(2+) and Fe(3+) salts from aqueous solution by ammonia solution. These magnetic nanoparticles of the adsorbent Fe(3)O(4) were characterized by surface area (BET), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infrared Spectroscopy (FT-IR). The effects of various parameters, such as contact time, pH, concentration, adsorbent dosage and temperature were studied. The kinetics followed is first order in nature, and the value of rate constant was found to be 1.90×10(-2) min(-1) at 100 mg L(-1) and 303 K. Removal efficiency decreases from 99 to 87% by increasing the concentration of Ni(II) in solution from 50 to 100 mg L(-1). It was found that the adsorption of Ni(II) increases by increasing temperature from 303 to 323 K and the process is endothermic in nature. The adsorption isotherm data were fitted to Langmuir and Freundlich equation, and the Langmuir adsorption capacity, Q°, was found to be (38.3)mgg(-1). The results also revealed that nanoparticle impregnated onto tea waste from agriculture biomass, can be an attractive option for metal removal from industrial effluent.
Rectal gland of Bactrocera papayae: ultrastructure, anatomy, and sequestration of autofluorescent compounds upon methyl eugenol consumption by the male fruit fly

Khoo CC, Tan KH

Microsc Res Tech, 2005 Aug 1;67(5):219-26.
PMID: 16170821 DOI: 10.1002/jemt.20199

Sexually mature males of Bactrocera papayae are strongly attracted to and consume methyl eugenol (ME). Upon consumption, ME is biotransformed to two phenylpropanoids, 2-allyl-4,5-dimethoxyphenol (DMP) and (E)-coniferyl alcohol (CF), that are transported in the hemolymph, sequestered and stored in the rectal glands, and subsequently released as sex and aggregation pheromones during courtship. To date, very little work on the ultrastructure and anatomy of the rectal gland has been done, and the accumulation of phenylpropanoids in the rectal glands of males has not been observed visually. Our objectives are to describe the anatomy and fine structures of the rectal glands of males and females and to observe the accumulation of autofluorescent compounds in the rectal glands of males. The rectal glands of males and females have four rectal papillae with each papilla attached to a rectal pad. The rectal pads protrude from the rectal gland as the only surfaces of the gland that are not surrounded by muscles. The rectal papillae of ME-fed males had oil droplets and autofluorescent compounds that were absent from those of ME-deprived males. The autofluorescent compounds accumulated in the rectal sac, which is an evagination that is not found in rectal glands of females. The accumulation of these compounds increased with time and reached maximum at a day post-ME feeding and decreased thereafter. This trend is similar to the accumulation pattern of phenylpropanoids, CF and DMP in the rectal gland.
Evidence of natural hybridization between two sympatric sibling species of Bactrocera dorsalis complex based on pheromone analysis

Wee SL, Tan KH

J Chem Ecol, 2005 Apr;31(4):845-58.
PMID: 16124255 DOI: 10.1007/s10886-005-3548-6

Bactrocera carambolae and B. papayae are major fruit fly pests and sympatric sibling species of the B. dorsalis complex. They possess distinct differences in male pheromonal components. In the 1990's, wild Bactrocera fruit flies with morphological traits intermediate between those of B. carambolae and B. papayae were often captured in traps baited with methyl eugenol (ME). Chemical analyses of rectal glands of ME-fed males revealed that the laboratory Fl, F2, and backcross hybrids possessed ME-derived sex pheromonal components ranging from that typical of B. papayae to that of B. carambolae without any specific trend, which included a combination of pheromonal components from both parental species within an individual hybrid. ME-fed hybrids without any ME-derived pheromonal components were also detected. Further chemical analysis of rectal glands from wild Bactrocera males, after ME feeding in the laboratory, showed a combination of pheromonal components similar to that found in the ME-fed, laboratory-bred hybrids. These findings present circumstantial evidence for the occurrence of a natural hybrid of the two Bactrocera species.
Fluoride exposure from ingested toothpaste in 4-5-year-old Malaysian children

Siew Tan B, Razak IA

Community Dent Oral Epidemiol, 2005 Oct;33(5):317-25.
PMID: 16128790

The aim of this study was to assess (by direct determination) the fluoride (F) exposure from ingested toothpaste among 4-5-year-old Malaysian children.
Clinicopathologic and immunohistochemical differences in complete and partial hydatidiform moles in a multiracial Malaysian population

Hayati AR, Tan GC

Int J Gynecol Pathol, 2005 Jul;24(3):277-85.
PMID: 15968205
Fulltext Appropriateness of colonoscopy in a university hospital

Tan YM, Goh KL

Med J Malaysia, 2004 Mar;59(1):34-8.
PMID: 15535333 MyJurnal

An open access endoscopy system allows for the direct scheduling of endoscopies by non-gastroenterologist physicians without prior gastroenterology consultation. The aim of our study was to examine our practice of open access endoscopy by evaluating the appropriateness of referrals for colonoscopy and to determine whether there were differences depending on the specialty of the referring clinician. The indication for colonoscopy was assessed in 499 consecutive outpatients referred for colonoscopy at University Hospital, Kuala Lumpur over a 12-month period. The American Society of Gastrointestinal Endoscopy (ASGE) guidelines were used to determine the appropriateness of referrals. 80.6% of colonoscopies requested by the gastroenterologist were performed for accepted indications compared to 50.6% of referrals by the primary care physician (p<0.001) and 67.0% of referrals by the surgeon (p=0.006). The rate of colonoscopies generally not indicated was 2.1% for the gastroenterologist, 25.0% for the internist (p=0.002) and 7.5% for the surgeon (p=0.04). The rate of indications not listed in the ASGE guidelines was significantly lower for requests made by gastroenterologists (17.3%) than those requested by primary care physicians (44.2%; p<0.001). Patients who have had prior consultation with the gastroenterologist were significantly more likely to undergo colonoscopy for appropriate indications than among patients who were referred through an open access system. The rate of inappropriate indications for colonoscopy was also significantly lower when the gastroenterologist made the referral. A substantial proportion of colonoscopies (25.4%) was performed for indications not listed in the ASGE guidelines.
Isolation of palm oil-utilising, polyhydroxyalkanoate (PHA)-producing bacteria by an enrichment technique

Alias Z, Tan IK

Bioresour Technol, 2005 Jul;96(11):1229-34.
PMID: 15734309

In early attempts to isolate palm oil-utilising bacteria from palm oil mill effluent (POME), diluted liquid samples of POME were spread on agar containing POME as primary nutrient. 45 purified colonies were screened for intracellular lipids by staining with Sudan Black B. Of these, 10 isolates were positively stained. The latter were grown in a nitrogen-limiting medium with palm olein (a triglyceride) or saponified palm olein (salts of fatty acids) as carbon source. None of the isolates grew in the palm olein medium but all grew well in the saponified palm olein medium. Of the latter however, only one isolate was positively stained with Nile Blue A, indicating the presence of PHA. This method did not successfully generate bacterial isolates which could metabolise palm olein to produce PHA. An enrichment technique was therefore developed whereby a selective medium was designed. The latter comprised minerals and palm olein (1% w/v) as sole carbon source to which POME (2.5% v/v) was added as the source of bacteria. The culture was incubated with shaking at 30 degrees C for 4 weeks. Out of seven isolates obtained from the selective medium, two isolates, FLP1 and FLP2, could utilise palm olein for growth and production of the homopolyester, poly(3-hydroxybutyrate). FLP1 is gram-negative and is identified (BIOLOG) to have 80% similarity to Burkholderia cepacia. When grown with propionate or valerate, FLP1 produced a copolyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate).
p53 alterations in sequential biopsies of Asian follicular lymphoma: a study of immunohistochemical staining pattern and gene mutations by PCR-SSCP in paraffin-embedded tissues

Shaminie J, Peh SC, Tan J

Pathology, 2005 Feb;37(1):39-44.
PMID: 15875732

AIM: Tumour suppressor gene p53 is a common target in carcinogenesis, reported to be altered and functionally inactive in 70% of human cancers. Although p53 mutations are less commonly present in haematological malignancies when compared with other solid tumours, they have been reported in histological transformation of follicular lymphoma. We aimed to investigate the frequency of p53 gene alterations in paraffin-embedded tissue using commercially available PCR-SSCP, and to correlate the results with P53 protein expression by immunohistochemistry.
METHODS: Surgical samples from seven patients with a total of 17 sequential biopsies were retrieved for the study of p53 gene expression using immunohistochemical stain, and gene status by PCR-SSCP for exons 5-8. The tumours were graded according to the WHO classification criteria. P53 was distinctly over-expressed in five transformed higher grade biopsies, and all except one showed electrophoretic mobility shift in PCR-SSCP analysis. Sequencing analysis revealed single nucleotide substitutions in three of four of these high-grade transformed cases with band shift (75%), whereas some other studies reported a lower frequency of 25-30%, and mobility shift result was found to correlate with P53 expression. Lower grade tumours without P53 over-expression did not demonstrate band shift, and sequencing analysis did not reveal mutations.
CONCLUSIONS: We demonstrated the feasibility of adopting PCR-SSCP for screening of p53 mutations in archival tissue samples in this study, and there is a strong correlation of p53 gene over-expression and mutation events in high-grade transformed tumours.
Late-onset marrow aplasia due to imatinib in newly diagnosed chronic phase chronic myeloid leukaemia

Chng WJ, Tan LH

Leuk. Res., 2005 Jun;29(6):719-20.
PMID: 15863215
Male sex pheromonal components derived from methyl eugenol in the hemolymph of the fruit fly Bactrocera papayae

Hee AK, Tan KH

J Chem Ecol, 2004 Nov;30(11):2127-38.
PMID: 15672660 DOI: 10.1023/B:JOEC.0000048778.02561.70

Pharmacophagy of methyl eugenol (ME)--a highly potent male attractant, by Bactrocera papayae results in the hydroxylation of ME to sex pheromonal components, 2-ally-4,5-dimethoxyphenol (DMP) and (E)-coniferyl alcohol (CF). These compounds, which are also male attractants, are then sequestered and stored in the rectal gland prior to their release during courtship at dusk. Chemical analyses of the digestive tract (excluding the crop and rectal gland) showed the absence of the sex pheromonal components and their precursor, ME. However, B. papayae males were attracted to and fed on the ME-fed male hemolymph extracts but not on hemolymph extracts of ME-deprived males. After thin layer chromatography in a hexane:ethyl acetate solvent system, flies were attracted to and fed on the original point on the TLC plate where the hemolymph extract had been spotted, suggesting that the pheromone components were bound in polar complexes. Chemical analyses of the ME-fed male hemolymph and crop extracts revealed the presence of the sex pheromonal components. The presence of the ME-derived pheromonal components and the absence of ME in the hemolymph suggest that the hemolymph is involved in the transportation of sex pheromonal components from the crop to the rectal gland.
Cervical cancer screening in Malaysia: Are targeted interventions necessary?

Dunn RA, Tan AKG

Soc Sci Med, 2010 Sep;71(6):1089-93.
PMID: 20685019 DOI: 10.1016/j.socscimed.2010.06.016

This study examines the determinants of Papanicolaou Smear Test (PST) screening for cervical cancer among women in Malaysia. Attention is focused on the reasons different population subgroups give for non-screening. We find that Indian women are the least likely to have had a PST and also the least likely to know the reasons why one is screened. Malay women are less likely than Chinese women to have received a PST and are more likely to report embarrassment as the reason for not being tested. Urban women are less likely than rural women to have been tested and more likely to state lack of time as the reason. These results suggest targeted interventions may be necessary to increase screening rates in Malaysia.
Study name: Malaysia Non-Communicable Disease Surveillance-1 (MyNCDS-1) survey
The introduction, origin and life-history attributes of the non-native cichlid Etroplus suratensis in the coastal waters of Singapore

Ng TH, Tan HH

J Fish Biol, 2010 Jun;76(9):2238-60.
PMID: 20557661 DOI: 10.1111/j.1095-8649.2010.02642.x

Etroplus suratensis, a southern Asian cichlid, has established populations in Singapore. The fish, which was first collected in 1995, was probably introduced via the aquarium trade or through the Johor River in Malaysia. The growth, feeding and reproductive characteristics were found to follow its ecology in its native range in southern Asia, and its establishment in Singapore could be due to the similarity in environment and availability of food. Changes in intestinal length indicated diet shifts from a predominantly herbivorous to an omnivorous one as it matured. Stomach contents did not provide comparable evidence. Diet similarity to two other introduced cichlids may imply that interspecies resource competition exists. Closer monitoring is needed to determine its effects on the local environment.
Fulltext Infective endocarditis in pregnancy complicated by septic embolization to the cerebellum

Tan HJ, Rabani R, Noorfaizan S

Med J Malaysia, 2007 Aug;62(3):249-50.
PMID: 18246919 MyJurnal

This report describes a pregnant lady in early trimester that was admitted with fever and left loin pain and was initially treated as presumed pyelonephritis. Subsequently she was found to have infective endocarditis with vegetation on the mitral valve. The course of her illness was complicated by acute pulmonary edema and septic embolization to the cerebellum. A decompressive craniectomy and resection of the lateral lobe of cerebellum was performed. Although the presenting features and risk factors are well described, the atypical presentations of infective endocarditis in pregnancy remain a diagnostic challenge for the treating physician. This report highlights the importance of rapid detection of endocarditis in pregnancy and the treatment of systemic complications.
Fulltext Open septorhinoplasty: operative technique and grafts

Gendeh BS, Tan VE

Med J Malaysia, 2007 Mar;62(1):13-8.
PMID: 17682563 MyJurnal

In this case series, the senior author details his series of patients who had undergone open septorhinoplasty for functional and/or aesthetic purposes in the Otorhinolaryngology Department at the Hospital Universiti Kebangsaan Malaysia (HUKM), Kuala Lumpur between January 2003 and September 2005. There were 23 patients, consisting of 15 men and 8 women from different Malaysian ethnic groups. Discussion on open septorhinoplasty with regards to operative technique, grafts and implants is presented from an otorhinolaryngologist's point of view.
Evidence of plasmotomy in Blastocystis hominis

Tan TC, Suresh KG

Parasitol Res, 2007 Nov;101(6):1521-5.
PMID: 17701428

Blastocystis hominis has been regarded as an enigmatic parasite as many aspects of its basic biology remain uncertain. Many reproductive processes have been suggested for the organism; however, to date, only the binary fission has been proven. Plasmotomy is one of the modes of reproduction previously suggested to be seen in in vitro cultures. The present study provides trichrome and acridine orange staining evidence for the existence of nucleic acid suggestive of division of nucleus into multinucleate forms with the respective cytoplasm dividing giving rise to two or three progeny B. hominis. Transmission electron micrographs further confirmed that these daughter cells had respective surrounding surface coat, mitochondria, and vacuoles.
Biological properties of TW01 cells expressing latent membrane protein-1 gene of EBV-derived from nasopharyngeal carcinoma cells at different stages of malignancy

Tan EL, Sam CK

Exp Oncol, 2007 Sep;29(3):166-74.
PMID: 18004239

Epstein-Barr virus (EBV), a human gammaherpesvirus is intimately associated with nasopharyngeal carcinoma (NPC), with the incidence of the virus detected in malignant tissues being close to 100% in NPC endemic areas. The viral latent gene, latent membrane protein 1 (LMP1), has all the typical characteristics of an oncogene and extensive studies have shown beyond doubt its abilities in cellular transformation giving rise to malignant phenotypes. The present study compares the gene sequence and biological properties of LMP1 gene derived from two patients with different stages of NPC--one presented with dysplastic, pre-malignant lesion and the other with malignant lesion.

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