Browse publications by year: 2007

1. Gastro-oesophageal reflux disease in chronic laryngitis: prevalence and response to acid-suppressive therapy

   Qua CS, Wong CH, Gopala K, Goh KL

   Aliment Pharmacol Ther, 2007 Feb 1;25(3):287-95.

   PMID: 17269990

   Abstract

   Gastro-oesophageal reflux is thought to cause chronic laryngitis through laryngopharyngeal reflux. Response of laryngitis to treatment with acid-suppressive therapy supports this causal link.

   MeSH terms: Adult; Anti-Ulcer Agents/therapeutic use*; Female; Gastroesophageal Reflux/complications*; Humans; Laryngitis/etiology*; Male; Middle Aged; Prospective Studies; Cohort Studies; Proton Pumps/therapeutic use; 2-Pyridinylmethylsulfinylbenzimidazoles/therapeutic use*; Proton Pump Inhibitors*; Lansoprazole
2. Automated detection of obstructive apnea and hypopnea events from oxygen saturation signal

   Lee YK, Bister M, Blanchfield P, Salleh YM

   Conf Proc IEEE Eng Med Biol Soc, 2007 2 3;2006:321-4.

   PMID: 17271675

   Abstract

   Our objective is to automate the detection of apnea and hypopnea events in obstructive sleep apnea hypopnea (OSAH) syndrome based on analysis of arterial oxygen saturation signal alone. This is the first attempt where wavelet is used to detect OSAH events. Detection of OSAH events through wavelet depends on the fluctuations in the magnitude of the transformed coefficients, thus circumventing the problem of variability in the criteria on the magnitude and duration of the signal. Our work evaluates the performance of the wavelet transform to detect OSAH events against three conventional amplitude and duration algorithms. High performance in the detection of OSAH events can be achieved through the wavelet algorithm (score 96.55%, sensitivity 95.74% and specificity 97.02%) if the threshold on wavelet coefficients is individually tuned for each study. However, this is impossible in clinical practice. It is interesting to observe that the conventional methods based on amplitude and duration are able to attain a performance as close as this. The Nervus algorithm obtains the best result (score 96.66%, sensitivity 95.26% and specificity 97.46%) compared to the amplitude duration algorithm, the drop duration algorithm and the wavelet algorithm with global threshold, in descending order of performance.
3. Classification of mental tasks using fixed and adaptive autoregressive models of EEG signals

   Nai-Jen H, Palaniappan R

   Conf Proc IEEE Eng Med Biol Soc, 2007 2 3;2006:507-10.

   PMID: 17271724

   Abstract

   Classification of EEG signals extracted during mental tasks is a technique for designing brain computer interfaces (BCI). We classify EEG signals that were extracted during mental tasks using fixed autoregressive (FAR) and adaptive AR (AAR) models. Five different mental tasks from 4 subjects were used in the experimental study and combinations of 2 different mental tasks are studied for each subject. Four different feature extraction methods were used to extract features from these EEG signals: FAR coefficients computed with Burg's algorithm using 125 data points, without segmentation and with segmentation of 25 data points, AAR coefficients computed with least-mean-square (LMS) algorithm using 125 data points, without segmentation and with segmentation of 25 data points. Multilayer perception (MLP) neural network (NN) trained by the backpropagation (BP) algorithm is used to classify these features into the different categories representing the mental tasks. The best results for FAR was 92.70% while for AAR was only 81.80%. The results obtained here indicated that FAR using 125 data points without segmentation gave better classification performance as compared to AAR, with all other parameters constant.
4. Parametric differential approach for modeling the upper limb human vasculature

   Zahedi E, Alauddin Mohd Ali M

   Conf Proc IEEE Eng Med Biol Soc, 2007 2 3;2006:742-5.

   PMID: 17271784

   Abstract

   A parametric approach is proposed for the characterization of the upper vascular tree. The novelty of the approach resides in it being differential: the processed signals are the photoplethysmograms obtained non-invasively from the left and right indexes. The investigated model is an ARX (auto-regressive with exogenous input) where the order has been estimated utilizing standard techniques. The model coefficients show a relatively high degree of stability.
5. Establishment and characterization of Asian oral cancer cell lines as in vitro models to study a disease prevalent in Asia

   Hamid S, Lim KP, Zain RB, Ismail SM, Lau SH, Mustafa WM, et al.

   Int J Mol Med, 2007 Mar;19(3):453-60.

   PMID: 17273794

   Abstract

   We have established 3 cell lines ORL-48, -115 and -136 from surgically resected specimens obtained from untreated primary human oral squamous cell carcinomas of the oral cavity. The in vitro growth characteristics, epithelial origin, in vitro anchorage independency, human papilloma-virus (HPV) infection, microsatellite instability status, karyotype and the status of various cell cycle regulators and gatekeepers of these cell lines were investigated. All 3 cell lines grew as monolayers with doubling times ranging between 26.4 and 40.8 h and were immortal. Karyotyping confirmed that these cell lines were of human origin with multiple random losses and gains of entire chromosomes and regions of chromosomes. Immunohistochemistry staining of cytokeratins confirmed the epithelial origin of these cell lines, and the low degree of anchorage independency expressed by these cell lines suggests non-transformed phenotypes. Genetic analysis identified mutations in the p53 gene in all cell lines and hypermethylation of p16INK4a in ORL-48 and -136. Analysis of MDM2 and EGFR expression indicated MDM2 overexpression in ORL-48 and EGFR overexpression in ORL-136 in comparison to the protein levels in normal oral keratinocytes. Analysis of the BAT-26 polyadenine repeat sequence and MLH-1 and MSH-2 repair enzymes demonstrated that all 3 cell lines were microsatellite stable. The role of HPV in driving carcinogenesis in these tumours was negated by the absence of HPV. Finally, analysis of the tissues from which these cell lines were derived indicated that the cell lines were genetically representative of the tumours, and, therefore, are useful tools in the understanding of the molecular changes associated with oral cancers.

   MeSH terms: Aged; Asia/epidemiology; Base Sequence; Chromosomes, Human/genetics; DNA Mutational Analysis; Female; Humans; Karyotyping; Male; Middle Aged; Molecular Sequence Data; Mouth Neoplasms/epidemiology*; Mouth Neoplasms/pathology*; Mouth Neoplasms/virology; Receptor, Epidermal Growth Factor/metabolism; Repetitive Sequences, Nucleic Acid; Prevalence; Tumor Suppressor Protein p53/genetics; Cell Cycle Proteins/genetics; Papillomaviridae; Papillomavirus Infections/virology; Asian Continental Ancestry Group*; Proto-Oncogene Proteins c-mdm2/metabolism; Microsatellite Instability
6. Introducing external cephalic version in a Malaysian setting

   Yong SP

   Hong Kong Med J, 2007 Feb;13(1):40-5.

   PMID: 17277391

   Abstract

   To assess the outcome of external cephalic version for routine management of malpresenting foetuses at term.

   MeSH terms: Adult; Amniotic Fluid; Cesarean Section/statistics & numerical data; Female; Humans; Labor Presentation*; Malaysia; Parity; Pregnancy; Pregnancy Outcome; Prospective Studies; Version, Fetal*; Tocolytic Agents/administration & dosage; Tocolytic Agents/adverse effects; Patient Satisfaction
7. Human enterovirus 71 disease in Sarawak, Malaysia: a prospective clinical, virological, and molecular epidemiological study

   Ooi MH, Wong SC, Podin Y, Akin W, del Sel S, Mohan A, et al.

   Clin Infect Dis, 2007 Mar 01;44(5):646-56.

   PMID: 17278054

   Abstract

   BACKGROUND: Human enterovirus (HEV)-71 causes large outbreaks of hand-foot-and-mouth disease with central nervous system (CNS) complications, but the role of HEV-71 genogroups or dual infection with other viruses in causing severe disease is unclear.

   METHODS: We prospectively studied children with suspected HEV-71 (i.e., hand-foot-and-mouth disease, CNS disease, or both) over 3.5 years, using detailed virological investigation and genogroup analysis of all isolates.

   RESULTS: Seven hundred seventy-three children were recruited, 277 of whom were infected with HEV-71, including 28 who were coinfected with other viruses. Risk factors for CNS disease in HEV-71 included young age, fever, vomiting, mouth ulcers, breathlessness, cold limbs, and poor urine output. Genogroup analysis for the HEV-71-infected patients revealed that 168 were infected with genogroup B4, 68 with C1, and 41 with a newly emerged genogroup, B5. Children with HEV-71 genogroup B4 were less likely to have CNS complications than those with other genogroups (26 [15%] of 168 vs. 30 [28%] of 109; odds ratio [OR], 0.48; 95% confidence interval [CI], 0.26-0.91; P=.0223) and less likely to be part of a family cluster (12 [7%] of 168 vs. 29 [27%] of 109; OR, 0.21; 95% CI, 0.10-0.46; P

   MeSH terms: Central Nervous System Diseases/complications; Central Nervous System Diseases/epidemiology; Central Nervous System Diseases/virology; Child; Child, Preschool; Enterovirus/classification; Enterovirus/genetics*; Enterovirus/isolation & purification; Genotype; Hand, Foot and Mouth Disease/complications; Hand, Foot and Mouth Disease/epidemiology*; Hand, Foot and Mouth Disease/virology; Humans; Infant; Malaysia/epidemiology; Phylogeny; Prospective Studies; Risk Factors
8. IMP-4-producing Pseudomonas aeruginosa in a French patient repatriated from Malaysia: impact of early detection and control measures

   Bert F, Vanjak D, Leflon-Guibout V, Mrejen S, Delpierre S, Redondo A, et al.

   Clin Infect Dis, 2007 Mar 1;44(5):764-5.

   PMID: 17278079

   MeSH terms: Aged; Bacterial Proteins/genetics; Bacterial Proteins/metabolism*; beta-Lactamases/genetics; beta-Lactamases/metabolism*; Cross Infection/prevention & control*; Disease Outbreaks/prevention & control; France; Humans; Malaysia; Male; Pseudomonas aeruginosa/enzymology*; Pseudomonas aeruginosa/genetics; Pseudomonas aeruginosa/isolation & purification; Pseudomonas Infections/diagnosis; Pseudomonas Infections/microbiology; Pseudomonas Infections/prevention & control*; Travel
9. Analysis of water compartment in dengue patients

   Ibrahim F, Ooi KF, Ismail NA, Taib MN, Wan Abas WA

   Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:4130-3.

   PMID: 17281142

   Abstract

   This paper describes the water compartments in healthy subjects and dengue patients on the day of defervescence of fever using bioelectrical impedance analysis. A total of 223 healthy subjects (65 males and 158 females) and 210 dengue patients (119 males and 91 females) in Hospital Universiti Kebangsaan Malaysia (HUKM), were studied. The ages for healthy subjects vary between 14 and 60 years old with mean age of 26.05 years while the ages for the dengue patients vary between 12 and 83 years old with mean age of 30.14 years. The parameters of water compartments investigated were total body water (TBW), extracellular water (ECW) and intracellular water (ICW). There were significant difference between healthy subjects and dengue patients for both male (p<0.05) and female (p<0.001) beginning on fever day 0 till fever day 4. The mean TBW and ECW values of dengue patients obtained were found to be higher than the normal healthy subjects while the mean ICW was lower. The mean TBW and ICW for male were higher than female while the mean ECW for male was lower than female for healthy subjects and dengue patients.
10. Selection of a Subset of EEG Channels using PCA to classify Alcoholics and Non-alcoholics

    Ong KM, Thung KH, Wee CY, Paramesran R

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:4195-8.

    PMID: 17281159

    Abstract

    The Principal Component Analysis (PCA) is proposed as feature selection method in choosing a subset of channels for Visual Evoked Potentials (VEP). The selected channels are to preserve as much information present as compared to the full set of 61 channels as possible. The method is applied to classify two categories of subjects: alcoholics and non-alcoholics. The electroencephalogram (EEG) was recorded when the subjects were presented with single trial visual stimuli. The proposed method is successful in selecting the a subset of channels that contribute to high accuracy in the classification of alcoholics and non-alcoholics.
11. Coordinate systems integration for development of malaysian craniofacial database

    Rajion Z, Suwardhi D, Setan H, Chong A, Majid Z, Ahmad A, et al.

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:5112-5.

    PMID: 17281397

    Abstract

    This study presents a data registration method for craniofacial spatial data of different modalities. The data consists of three dimensional (3D) vector and raster data models. The data is stored in object relational database. The data capture devices are Laser scanner, CT (Computed Tomography) scan and CR (Close Range) Photogrammetry. The objective of the registration is to transform the data from various coordinate systems into a single 3-D Cartesian coordinate system. The standard error of the registration obtained from multimodal imaging devices using 3D affine transformation is in the ranged of 1-2 mm. This study is a step forward for storing the spatial craniofacial data in one reference system in database.
12. Noise removal of ECG S signals using Legendre moments

    Kwan BH, Ong KM, Paramesran R

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:5627-30.

    PMID: 17281532

    Abstract

    This paper proposes a method to remove the noise in the ECG (Electrocardiogram) signals using Legendre moments. Noise is removed in the reconstructed ECG signals when lower order Legendre moments are used. RMSE (Root Mean Square Error) is used as the distortion measure for the reconstructed ECG signals. With sampling rate of 256 Hz and number of moments used is 13% of the data in each interval, experimental results show that reconstruction of ECG signal using Legendre moments can produce a smoother signal without noise while maintaining signal quality that is acceptable to cardiologist.
13. A statistical comparison of digital X-Ray images for MTB patients

    Mohd Rijal O, Mohd Noor N, Shaban H, Lee Teng S

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:6418-21.

    PMID: 17281737

    Abstract

    A common practice in medical diagnosis and patient management is the comparison of two chest radiographs images. The difference between two digital images at two time points is a measure of the effect of treatment on the patient. Two measures of similarity, the ordinary regression coefficients, R(s)(2) and coefficients of determination for the Unreplicated linear functional relationship model (ULFR), R(f) (2), are used to compare images for the particular case of Mycobacterium Tuberculosis (MTB). Our results suggest that a series of R2 values indicates gradual declining trends with values falling within a band. New patients with a series of R2 values falling within this band may be consider as making a good or acceptable recovery.
14. 3D CT Imaging for Craniofacial Analysis Based on Anatomical Regions

    Wan Harun WA, Ahmad Rajion Z, Abdul Aziz I, Rani Samsudin A

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2006:817-20.

    PMID: 17282309

    Abstract

    The development of a craniofacial database is a multidisciplinary initiative that will provide an important reference for community, security, social and medical applications. A method of landmark identifications and measurements in 3d on craniofacial patients is described. anatomical regions such as mandible, orbits, zygoma and maxilla are located, created and stored as templates of 3D CAD files for subsequent analysis. Data from these images were tested for accuracy and repeatability by comparing with direct measurements using caliper and CMM. The landmark points are reproducible in CAD system for further analysis. it was found that the approach provides a fast, accurate and efficient method for landmarks identification of the craniofacial areas in database development.
15. Variable selection using genetic algorithm for analysis of near-infrared spectral data using partial least squares

    Siang Soh C, Meng Ong K, Raveendran P

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:1178-81.

    PMID: 17282402

    Abstract

    Genetic algorithm is used to perform variable selection to determine the ranges of wavelengths in NIR spectral data suitable to be used as predictors in multivariate calibration model via partial least squares. The NIR spectral data consists of three components of active substances, namely human serum albumin (HSA), γ-globulin and glucose. The wavelength selection is able to improve the calibration model by selecting the wavelengths that contains information or correlated with the concentration of substances, while others non-chosen wavelengths, which contribute no information or contain noises, are excluded from the calibration model.
16. Dual-channel photoplethysmography synchronization using a Barker sequence

    Zahedi E, M Ali M

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:1952-5.

    PMID: 17282604

    Abstract

    A Barker sequence is employed for the synchronization of two photoplethysmogram (PPG) channels. The correctness of this technique is demonstrated by recording a PPG signal, injecting a Barker sequence at the start of this trace and producing a delayed version of it. After preprocessing, cross-correlation techniques are utilized for accurate time alignment of the two traces. The algorithm can correct for any time misalignment as long as the synchronization sequence appears on both channels.
17. Image Cytometry Data From Breast Lesions Analyzed using Hybrid Networks

    Mat Sakim HA, Mat Isa NA, G Naguib R, Sherbet G

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:2059-62.

    PMID: 17282632

    Abstract

    The treatment and therapy to be administered on breast cancer patients are dependent on the stage of the disease at time of diagnosis. It is therefore crucial to determine the stage at the earliest time possible. Tumor dissemination to axillary lymph nodes has been regarded as an indication of tumor aggression, thus the stage of the disease. Neural networks have been employed in many applications including breast cancer prognosis. The performance of the networks have often been quoted based on accuracy and mean squared error. In this paper, the performance of hybrid networks based on Multilayer Perceptron and Radial Basis Function networks to predict axillary lymph node involvement have been investigated. A measurement of how confident the networks are with respect to the results produced is also proposed. The input layer of the networks include four image cytometry features extracted from fine needle aspiration of breast lesions. The highest accuracy achieved by the hybrid networks was 69% only. However, most of the correctly predicted cases had a high confidence level.
18. Assessing Auditory Discrimination Skill of Malay Children Using Computer-based Method

    Ting H, Yunus J, Mohd Nordin MZ

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:2498-501.

    PMID: 17282745

    Abstract

    The purpose of this paper is to investigate the auditory discrimination skill of Malay children using computer-based method. Currently, most of the auditory discrimination assessments are conducted manually by Speech-Language Pathologist. These conventional tests are actually general tests of sound discrimination, which do not reflect the client's specific speech sound errors. Thus, we propose computer-based Malay auditory discrimination test to automate the whole process of assessment as well as to customize the test according to the specific speech error sounds of the client. The ability in discriminating voiced and unvoiced Malay speech sounds was studied for the Malay children aged between 7 and 10 years old. The study showed no major difficulty for the children in discriminating the Malay speech sounds except differentiating /g/-/k/ sounds. Averagely the children of 7 years old failed to discriminate /g/-/k/ sounds.
19. Discrimination between two lung diseases using chest radiographs

    Mohd Noor N, Mohd Rijal O, Shaban H, Ee Ling O

    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:3320-3.

    PMID: 17282956

    Abstract

    Economic considerations make the conventional chest radiograph (X-ray) film an important ingredient in the diagnostic process. An initial clinical investigation for patients with suspected lung ailments is the study of the chest X-rays. The problem of detection for diseases in their early stages are well known using X-ray. A technique involving wavelets coefficient as the feature vector and Andrew's Curve has been proposed for detection of Mycobacterium Tuberculosis (MTB). This paper presents new and important results whereby lung cancer (LC) may be detected and differentiated from MTB. A method to calculate misclassification probabilities is given.
20. Sequencing and analysis of chromosome 1 of Eimeria tenella reveals a unique segmental organization

    Ling KH, Rajandream MA, Rivailler P, Ivens A, Yap SJ, Madeira AM, et al.

    Genome Res, 2007 Mar;17(3):311-9.

    PMID: 17284678

    Abstract

    Eimeria tenella is an intracellular protozoan parasite that infects the intestinal tracts of domestic fowl and causes coccidiosis, a serious and sometimes lethal enteritis. Eimeria falls in the same phylum (Apicomplexa) as several human and animal parasites such as Cryptosporidium, Toxoplasma, and the malaria parasite, Plasmodium. Here we report the sequencing and analysis of the first chromosome of E. tenella, a chromosome believed to carry loci associated with drug resistance and known to differ between virulent and attenuated strains of the parasite. The chromosome--which appears to be representative of the genome--is gene-dense and rich in simple-sequence repeats, many of which appear to give rise to repetitive amino acid tracts in the predicted proteins. Most striking is the segmentation of the chromosome into repeat-rich regions peppered with transposon-like elements and telomere-like repeats, alternating with repeat-free regions. Predicted genes differ in character between the two types of segment, and the repeat-rich regions appear to be associated with strain-to-strain variation.

    MeSH terms: Animals; Base Sequence; Chromosome Mapping; Molecular Sequence Data; Polymorphism, Restriction Fragment Length; Eimeria tenella/genetics*; Genes, Protozoan/genetics*; Sequence Analysis, DNA; Minisatellite Repeats/genetics; Computational Biology; Chromosome Structures/genetics*