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Fulltext Review of forensically important entomological specimens in the period of 1972 - 2002

Lee HL, Krishnasamy M, Abdullah AG, Jeffery J

Trop Biomed, 2004 Dec;21(2):69-75.
PMID: 16493401

Forensic entomological specimens received by the Unit of Medical Entomology, IMR., from hospitals and the police in Malaysia in the last 3 decades (1972 - 2002) are reviewed. A total of 448 specimens were received. From these, 538 identifications were made with the following results: Eighteen species of cyclorrphaga flies were identified consisting of Chrysomya megacephala (Fabricius) 215 cases (47.99%), Ch. rufifacies (Masquart) 132 (29.46%), Ch. villeneuvi Patton 10 (2.23%), Ch. nigripes Aubertin 7 (1.56%), Ch. bezziana Villeneuve 4 (0.89%), Ch. pinguis (Walker) 1 (0.22%), Chrysomya sp. 47 (10.49%), Sarcophaga sp. 28 (6.25%), Lucilia sp. 21 (4.69%), Hermetia sp. 15 (3.35%), He. illucens (Linnaeus) 1 (0.22%), Hemipyrellia ligurriens (Wiedemann) 3 (0.67%), Hemipyrellia sp. 2 (0.45%), Ophyra spinigera 1 (0.22%), Ophyra sp. 6 (1.34%), Calliphora sp. 24 (5.36%), Synthesiomyia nudiseta (Wulp) 1 (0.22%) and Eristalis sp. 1 (0.22%). Other non - fly insect specimens are Pthirus pubis (Linnaeus) (Pubic louse) 2 (0.45%) and Coleoptera (Beetles) 1 (0.22%). Ch. megacephala and Ch. rufifacies were the commonest species found in cadavers from different ecological habitats. Sy. nudiseta is an uncommon species, thus far found only on cadavers from indoors. Sy. nudiseta is reported for the second time in Peninsular Malaysia. A total of 329 cases (73.44%) had a single fly infestation, 109 cases (24.33%) had double fly infestation and 10 cases (2.23%) had triple fly infestation. Five cases (1.12%) had eggs and 3 cases (0.67%) had larval stages that were not identifiable. No arthropods were retrieved from cadavers in 8 cases (1.79%). In conclusion, although large number of fly species were found on human cadavers, the predominant species are still those of Chrysomya.
Fulltext Adult and larval insecticide susceptibility status of Culex quinquefasciatus (Say) mosquitoes in Kuala Lumpur Malaysia

Nazni WA, Lee HL, Azahari AH

Trop Biomed, 2005 Jun;22(1):63-8.
PMID: 16880755 MyJurnal

The susceptibility of Culex quinquefasciatus to chemical insecticides in two field sites in Kuala Lumpur was evaluated using the WHO standard susceptibility test. Less then 7 days old female mosquitos, reared from wild caught females were exposed to discriminating dosages of insecticides at recommended exposure periods. The larval bioassay were conducted using the multiple concentrations and the LC50 value was determined. The results indicated that cyfluthrin is the most effective among all the insecticides tested with LT50 value of 29.95 min and 28.59 min, for the strain from Ampang Hill and Pantai Dalam, respectively. It was surprisingly to note that both these field strains showed 0% mortality when tested against malathion and DDT. The LC50 value indicated that both strains were highly resistant to malathion with resistance ratio of 17,988 folds and 14,053 folds, respectively. This concludes that resistance at larval stages is extremely high compared to adult stages.
Fulltext Rapid detection of chikungunya virus in laboratory infected Aedes aegypti by Reverse-Transcriptase- Polymerase Chain Reaction (RT-PCR)

Rohani A, Yulfi H, Zamree I, Lee HL

Trop Biomed, 2005 Dec;22(2):149-54.
PMID: 16883281 MyJurnal

A study of chikungunya virus was carried out to establish Reverse Transcriptase- Polymerase Chain Reaction (RT-PCR) as a rapid detection technique of the virus. The susceptibility of lab-colonized Aedes aegypti to chikungunya virus was also determined. Artificial membrane feeding technique was used to orally feed the mosquitoes with a human isolate of chikungunya virus. A total of 100 fully engorged female Ae. aegypti were obtained and maintained for 7 days. Seventy of them survived and then pooled at 10 individuals per pool. Total RNA was extracted from the samples and RT-PCR amplifications were carried out. Five out of 7 pools showed positive PCR band at 350-bp, indicating Ae. aegypti is a potential vector of chikungunya virus. The minimum infection rate (MIR) was 71% within these laboratory colonies. RT-PCR is a sensitive technique that is useful in detecting infected mosquitoes in epidemic areas. This technique can de used as a rapid detection method and provide an early virologic surveillance systems of chikungunya virus infected mosquitoes.
Fulltext Field bioefficacy of deltamethrin residual spraying against dengue vectors

Rozilawati H, Lee HL, Mohd Masri S, Mohd Noor I, Rosman S

Trop Biomed, 2005 Dec;22(2):143-8.
PMID: 16883280 MyJurnal

Field bioefficacy of residual-sprayed deltamethrin against Aedes vectors was evaluated in an urban residential area in Kuala Lumpur. The trial area consisted of single storey wood-brick houses and a block of flat. The houses were treated with outdoor residual spraying while the flat was used as an untreated control. Initial pre-survey using ovitrap surveillance indicated high Aedes population in the area. Deltamethrin WG was sprayed at a dosage of 25mg/m2 using a compression sprayer. The effectiveness of deltamethrin was determined by wall bioassay and ovitrap surveillance. The residual activity of 25mg/m2 deltamethrin was still effective for 6 weeks after treatment, based on biweekly bioassay results. Bioassay also indicated that both Aedes aegypti and Aedes albopictus were more susceptible on the wooden surfaces than on brick. Aedes aegypti was more susceptible than Ae. albopictus against deltamethrin. Residual spraying of deltamethrin was not very effective against Aedes in this study since the Aedes population in the study area did not reduce as indicated by the total number of larvae collected using the ovitrap (Wilcoxon Sign Test, p> 0.05). Further studies are required to improve the effectiveness of residual spraying against Aedes vectors.
Prevalence of elevated body mass index condition and its associated demographic variables among adults in urban areas in Johor, Malaysia

Rozita Z, Lim MT, Lee HS

Med J Malaysia, 2019 04;74(2):145-150.
PMID: 31079126

INTRODUCTION: The prevalence of overweight and obesity is increasing at an alarming rate. It is a major factor for many other metabolic disorders. This study aimed to determine the prevalence of increase body mass index (BMI) and obesity and their associated demographic characteristics among adults in an urban area.
METHODS: A retrospective study was conducted where data was extracted from the Health Status Screening Form (BSSK) at health clinics in Johor Bahru. Using the World Health Organization (WHO), criteria for obesity, BMI≥30.0 kg/m2 was specified as obese and combination of both BMI ranges for overweight (25.0-30.0kg/m2) and obesity (≥30.0kg/m2) as elevated BMI.
RESULTS: The overall prevalence of elevated BMI and obesity was 54.6% and 20.1% respectively. Men had a higher prevalence of elevated BMI (57.4%) with odds of 1.28 higher (95%CI: 1.04-1.58). High prevalence of elevated BMI and obesity were seen among the Indians (elevated BMI - 60.2%, obesity - 19.4%) followed by Malays (elevated BMI -57.8%, obesity - 23.1%) and Chinese showed the lowest (elevated BMI - 39.0%, obesity - 8.8%). The odds of elevated BMI and obesity were lower among younger adults as compared to older adults (≥30 years old).
CONCLUSION: Using WHO criteria, about one in two adults had elevated BMI while one in five were obese. Elevated BMI and obesity disparities were evident in age and ethnicity, but sex differences were encountered in elevated BMI group.
Hemorrhagic fever with renal syndrome: report of a case in Malaysia

Lim TW, Mangalam S, Lee HW

J Infect Dis, 1987 Dec;156(6):1035-6.
PMID: 2890691
Thermal application of Bacillus thuringiensis serovar israelensis for dengue vector control

Seleena P, Lee HL, Chiang YF

J Vector Ecol, 2001 Jun;26(1):110-3.
PMID: 11469179
Compatibility of Bacillus thuringiensis serovar israelensis and chemical insecticides for the control of Aedes mosquitoes

Seleena P, Lee HL, Chiang YF

J Vector Ecol, 1999 Dec;24(2):216-23.
PMID: 10672551

The compatibility of the commercial aqueous Bacillus thuringiensis serovar israelensis (B.t.i.) formulation, Vectobac 12AS, with the chemical insecticides Actellic 50EC, Aqua Resigen, Resigen, and Fendona SC, for the simultaneous control of Aedes larvae and adults was studied by dispersing nine different formulations using a portable mist blower, in single story half-brick houses. The effectiveness of the treatment was evaluated by measuring the larval mortality, adult mortality, and droplet analysis at varying distances from the sprayer. Persistence of the larvicidal activity of the chemical insecticides and B.t.i was also determined by measuring the larval mortality in the test samples 7 days posttreatment. The sprayed particles in all the trials were 50-60 microns in size, indicating that the particles were those of mist spray. Test samples placed within 3 m from the sprayer gave the maximum larval and adult mortality. Chemical insecticides exhibited maximum larval mortality in the 1 h posttreatment test samples and it was comparable to the larvicidal activity of B.t.i. The larvicidal toxins of B.t.i were more stable and were able to affect sufficient larval mortality for 7 days posttreatment. The larvicidal activity of the mixtures, i.e., chemical insecticides with B.t.i, in the 1 h posttreatment test samples was not significantly different from the larvicidal activity of the chemical insecticides and it was comparable to the larvicidal activity of B.t.i alone. However, the larvicidal activity of the mixtures was significantly more than the chemical insecticides alone in the 7 days posttreatment test samples except for the Actellic 50EC and Vectobac 12AS mixture. In all the trials, with or without B.t.i, there was no significant difference in adult mortality, indicating that this B.t.i formulation, Vectobac 12AS, was not antagonistic to the adulticidal activity of the chemical insecticides. From this study, it can be concluded that chemical insecticides can be used effectively for both adult and larval control, but the chemical insecticides do not exhibit residual larvicidal activity. Hence, for an effective control of both Aedes larvae and adults, it is advisable to add B.t.i. to the chemical insecticides, as B.t.i is specifically larvicidal and is also able to effect extended residual larvicidal activity.
Preliminary field evaluation of the combined adulticidal, larvicidal, and wall residual activity of ULV-applied bifenthrin against mosquitoes

Lee HL, Khadri MS, Chiang YF

J Vector Ecol, 1997 Dec;22(2):146-9.
PMID: 9491365

The combined adulticidal, larvicidal, and wall residual activity of ULV-applied bifenthrin, a synthetic pyrethroid, was evaluated in houses in Kuala Lumpur, Malaysia, against larvae and adults of lab-bred Aedes aegypti and Culex quinquefasciatus. A portable ULV sprayer was used to disperse a ULV formulation of bifenthrin at a discharge rate of 45 ml/min. The results indicated that bifenthrin sprayed at this rate exhibited all the three activities against the test mosquitoes. Complete adult mortalities were achieved, while very high larvicidal activity was also effected, which persisted for seven days. Wall bioassay with adults of Ae aegypti also resulted in very high mortality, which also persisted for one week. The combined mosquitocidal activities of bifenthrin is considered more effective especially in the control of dengue vectors.
Fulltext Vacuum delivery at The Maternity Hospital Kuala Lumpur: a comparison of metal and silicone cups

Lee HY, Subramaniam N, Nordin MM

Singapore Med J, 1996 Feb;37(1):55-60.
PMID: 8783915

To compare the advantages and disadvantages of the New Bird metal cups and silicone cups in terms of maternal and foetal outcome. To study the adverse effects and factors associated with failed vacuum deliveries.
Fulltext Detection of Wolbachia from field collected Aedes albopictus Skuse in Malaysia

Noor Afizah A, Roziah A, Nazni WA, Lee HL

Indian J Med Res, 2015 Aug;142(2):205-10.
PMID: 26354218 DOI: 10.4103/0971-5916.164259

Wolbachia-based vector control strategies have been proposed as a mean to augment the existing measures for controlling dengue vector. Prior to utilizing Wolbachia in novel vector control strategies, it is crucial to understand the Wolbachia-mosquito interactions. Many studies have only focused on the prevalence of Wolbachia in female Aedes albopictus with lack of attention on Wolbachia infection on the male Ae. albopictus which also affects the effective expression of Wolbachia induced- cytoplasmic incompatibility (CI). In this study, field surveys were conducted to screen for the infection status of Wolbachia in female and male Ae. albopictus from various habitats including housing areas, islands and seashore.
Fulltext Mapping of mosquito breeding sites in malaria endemic areas in Pos Lenjang, Kuala Lipis, Pahang, Malaysia

Ahmad R, Ali WN, Nor ZM, Ismail Z, Hadi AA, Ibrahim MN, et al.

Malar J, 2011;10:361.
PMID: 22166101 DOI: 10.1186/1475-2875-10-361

The application of the Geographic Information Systems (GIS) to the study of vector transmitted diseases considerably improves the management of the information obtained from the field survey and facilitates the study of the distribution patterns of the vector species.
Fulltext Phylogeographical pattern and evolutionary history of an important Peninsular Malaysian timber species, Neobalanocarpus heimii (Dipterocarpaceae)

Tnah LH, Lee SL, Ng KK, Lee CT, Bhassu S, Othman RY

J Hered, 2013 Jan-Feb;104(1):115-26.
PMID: 23132907 DOI: 10.1093/jhered/ess076

Tectonic movements, climatic oscillations, and marine transgressions during the Cenozoic have had a dramatic effect on the biota of the tropical rain forest. This study aims to reveal the phylogeography and evolutionary history of a Peninsular Malaysian endemic tropical timber species, Neobalanocarpus heimii (Dipterocarpaceae). A total of 32 natural populations of N. heimii, with 8 samples from each population were investigated. Fifteen haplotypes were identified from five noncoding chloroplast DNA (cpDNA) regions. Overall, two major genealogical cpDNA lineages of N. heimii were elucidated: a widespread southern and a northern region. The species is predicted to have survived in multiple refugia during climatic oscillations: the northwestern region (R1), the northeastern region (R2), and the southern region (R3). These putative glacial refugia exhibited higher levels of genetic diversity, population differentiation, and the presence of unique haplotypes. Recolonization of refugia R1 and R2 could have first expanded into the northern region and migrated both northeastwards and northwestwards. Meanwhile, recolonization of N. heimii throughout the southern region could have commenced from refugia R3 and migrated toward the northeast and northwest, respectively. The populations of Tersang, Pasir Raja, and Rotan Tunggal exhibited remarkably high haplotype diversity, which could have been the contact zones that have received an admixture of gene pools from the northerly and also southerly regions. As a whole, the populations of N. heimii derived from glacial refugia and contact zones should be considered in the conservation strategies in order to safeguard the long-term survival of the species.
Fulltext Stool patterns of Malaysian adults with functional constipation: association with diet and physical activity

Mazlyn MM, Nagarajah LH, Fatimah A, Norimah AK, Goh KL

Malays J Nutr, 2013 Apr;19(1):53-64.
PMID: 24800384 MyJurnal

Diet and lifestyle modification is commonly used in constipation management. As there is a dearth of studies on this topic in Malaysia, we aim to elucidate the relations between stool patterns, dietary intake and physical activity levels among adults with functional constipation.
Fulltext Conversion of lignocellulosic biomass to nanocellulose: structure and chemical process

Lee HV, Hamid SB, Zain SK

ScientificWorldJournal, 2014;2014:631013.
PMID: 25247208 DOI: 10.1155/2014/631013

Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.
Rapid identification of cyclic tetrapyrrolic photosensitisers for photodynamic therapy using on-line hyphenated LC-PDA-MS coupled with photo-cytotoxicity assay

Tan PJ, Appleton DR, Mustafa MR, Lee HB

Phytochem Anal, 2012 Jan-Feb;23(1):52-9.
PMID: 21692117 DOI: 10.1002/pca.1324

Photodynamic therapy is a treatment modality that involves site-directed generation of cytotoxic reactive oxygen species by light-activated photosensitisers.
Fulltext Care of severe head injury patients in the Sarawak General Hospital: intensive care unit versus general ward

Sim SK, Lim SL, Lee HK, Liew D, Wong A

Med J Malaysia, 2011 Jun;66(2):138-41.
PMID: 22106695 MyJurnal

Intensive care for severe head injury patients is very important in the prevention and treatment of secondary brain injury. However, in a resources constraint environment and limited availability of Intensive Care Unit (ICU) beds in the hospitals, not all severe head injury patients will receive ICU care. This prospective study is aimed to evaluate the outcome of severe head injured patients who received ICU and general ward care in Sarawak General Hospital (SGH) over a 6-month period. A total of thirty five severe head injury patients were admitted. Twenty three patients (65.7%) were ventilated in general ward whereas twelve patients (34.3%) were ventilated in ICU. Overall one month mortality in this study was 25.7%. Patients who received ICU care had a lower one month mortality than those who received general ward care (16.7% vs 30.4%), although it was not statistically different. Multivariate analysis revealed only GCS on admission (OR 0.731; 95% CI 0.460 to 0.877; P=0.042) as the independent predictive factor for one month mortality in this study.
Studies of phlebotomine sand fly (Diptera: Psychodidae) populations in limestone areas and caves of western Malaysia

Shahar MK, Hassan AA, Lee HL, Salmah MR

Southeast Asian J. Trop. Med. Public Health, 2011 Jan;42(1):83-93.
PMID: 21323169

Phlebotomine sand flies were collected using CO2 baited CDC light trap in 2000 and 2001 in limestone areas and caves of western Malaysia. A total of 1,548 specimens were collected comprising 18 species from two genera: Phlebotomus (6 spp) and Sergentomyia (12 spp). Phlebotomus major major (38.9%) was the predominant species followed by Sergentomyia perturbans (20.1%), P. stantoni (15.3%) and others. Biting activity of the sand flies at the Gua Senyum caves, Gua Kota Gelanggi, Batu caves and Gua Kelam were observed using the bare leg landing catch (BLC) technique. Four Phlebotomus spp at Gua Senyum were found to bite humans with a unimodal biting peak (between 01:00 and 04:00 AM). At Gua Kota Gelanggi P. major major was observed to bite humans, but at Batu Caves and Gua Kelam no sand flies were observed to bite humans. Sergentomyia spp did not feed on humans even though high numbers were caught in light traps. The populations of phleobotomine sand flies fluctuated, with several peaks especially among P. major major which peaked in December and was low in February and August. Phlebotomus stantoni was abundant throughout 2001. Most species populations were weakly related to rainfall because they inhabited caves.
Efficacy of commercial household insecticide aerosol sprays against Aedes aegypti (Linn.) under simulated field conditions

Khadri MS, Kwok KL, Noor MI, Lee HL

Southeast Asian J. Trop. Med. Public Health, 2009 Nov;40(6):1226-34.
PMID: 20578457

A simulated field study on the efficacy of commercial household aerosol insecticides was conducted. The bioefficacy of three pyrethroid aerosols, designated as PA1, PA2 and PA3, was tested in cabins furnished to simulate bedroom conditions. Each aerosol product was tested against lab-bred Aedes aegypti mosquitoes based on the insecticide manufacturers' recommended dosages. Ten cages with mosquitoes were placed in the following locations: one cage in the middle of the room; two each on and underneath the bed; three each placed inside, behind and on top of the wardrobe; and four placed on and in the desk. With the desk, each cage was placed inside each of three drawers (totally closed, partially closed and opened). Prior to the experiments, the discharge rate of each aerosol can was determined. Ten to 20 lab-bred 2-5 day-old sugar-fed Ae. aegypti adult mosquitoes were placed inside the test cages. The aerosol was then discharged into the cabin at the recommended dosage. After 30 minutes, the mosquitoes were transferred into clean paper cups and their mortality recorded after 24 hours. All the aerosols induced complete or very high mortality in the caged Ae. aegypti females, except in the cages hidden completely inside the drawers and wardrobes. Insecticide droplet analysis indicated variable uniformity of the droplets was produced. The aerosol insecticides were effective against mosquitoes provided they were used in accordance with the manufacturers' recommendations.
The effect of extrinsic incubation temperature on development of dengue serotype 2 and 4 viruses in Aedes aegypti (L.)

Rohani A, Wong YC, Zamre I, Lee HL, Zurainee MN

Southeast Asian J. Trop. Med. Public Health, 2009 Sep;40(5):942-50.
PMID: 19842378

Dengue 2 and 4 viruses obtained from dengue-infected patients were maintained in a C6/36 Aedes albopictus Skuse cell line and used to infect adult female Aedes aegypti mosquitoes. Each serotype was mixed separately with fresh human erythrocytes and fed to adult female mosquitoes using an artificial membrane feeding technique. Fully engorged mosquitoes were selected and retained at 26 degrees C, 28 degrees C and 30 degrees C to observe dengue virus development in Aedes vectors. Virus detection was carried out by reverse-transcriptase polymerase chain reaction (RT-PCR). The virus was first detected on Day 9 at 26 degrees C and 28 degrees C and on Day 5 at 30 degrees C for both dengue 2 and 4. The study shows the incubation period of the viruses decreased when the extrinsic incubation temperature increases.

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