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Fulltext Symptoms indicating imminent breakage of a femoral interlocking nail: a case report

Pan K, Chan W

Malays Orthop J, 2013 Nov;7(3):21-3.
PMID: 25674303 MyJurnal DOI: 10.5704/MOJ.1311.003

Fractures of the femoral shaft treated with interlocking nails will ultimately result in breakage of the nail if the bone does not unite. Further management requires removal of the broken nail which may be a difficult process for the distal segment. If we can identify the symptoms just before the nail breaks, an exchange nailing becomes much easier. We present a patient with fibromatosis who underwent repeated surgery as well as radiotherapy at the age of 16. Six years later, she had a pathological fracture of the upper third of the femur for which an interlocking nail was inserted. The femur did not unite and the nail subsequently broke. Over a period of 12 years, three nails broke and had to be replaced. Two to 3 months before each breakage, the patient experienced the same set of symptoms for each episode. Knowing that her fracture was not going to heal will now alert us to do an exchange nailing before the nail broke again. It is well known that where there is evidence of non-union, pre-emptive treatment is necessary before implant failure.
KEY WORDS: Femur nonunion, interlocking nail, symptoms before breakage of nail.
Initial symptoms and delayed diagnosis of osteosarcoma around the knee joint

Pan KL, Chan WH, Chia YY

J Orthop Surg (Hong Kong), 2010 Apr;18(1):55-7.
PMID: 20427835

To identify initial symptoms of osteosarcoma around the knee joint.
Fulltext Single-Bone Forearm Salvage Procedure for a Child with Acquired Radial Clubhand in a Resource Limited Centre: A Case Report

Sahdi H, Chan WH, Dollah NB, Entri A

Malays Orthop J, 2018 Nov;12(3):43-46.
PMID: 30555646 MyJurnal DOI: 10.5704/MOJ.1811.011

Acquired radial clubhand deformity can be a consequence of large bone gap left by premature extensive radius osteomyelitis sequestrectomy. Single-bone forearm reconstruction is a salvage procedure when other motion-preserving techniques are not feasible. Here we present a child who developed radial clubhand deformity after an untimely sequestrectomy of radius diaphysis. In view of limited microsurgical expertise in our centre, single-bone forearm procedure was done utilising simple Kirshner wires to achieve radio-ulnar fusion. The procedure resulted in pain-free stable wrist, restoration of hand function and improved cosmesis.
Enhancing infectious disease prediction model selection with multi-objective optimization: an empirical study

Xu D, Chan WH, Haron H

PeerJ Comput Sci, 2024;10:e2217.
PMID: 39145229 DOI: 10.7717/peerj-cs.2217

As the pandemic continues to pose challenges to global public health, developing effective predictive models has become an urgent research topic. This study aims to explore the application of multi-objective optimization methods in selecting infectious disease prediction models and evaluate their impact on improving prediction accuracy, generalizability, and computational efficiency. In this study, the NSGA-II algorithm was used to compare models selected by multi-objective optimization with those selected by traditional single-objective optimization. The results indicate that decision tree (DT) and extreme gradient boosting regressor (XGBoost) models selected through multi-objective optimization methods outperform those selected by other methods in terms of accuracy, generalizability, and computational efficiency. Compared to the ridge regression model selected through single-objective optimization methods, the decision tree (DT) and XGBoost models demonstrate significantly lower root mean square error (RMSE) on real datasets. This finding highlights the potential advantages of multi-objective optimization in balancing multiple evaluation metrics. However, this study's limitations suggest future research directions, including algorithm improvements, expanded evaluation metrics, and the use of more diverse datasets. The conclusions of this study emphasize the theoretical and practical significance of multi-objective optimization methods in public health decision support systems, indicating their wide-ranging potential applications in selecting predictive models.
Fulltext Large volume osteosarcomas of the femur treated with total femoral replacement

Pan K, Chan W, Shanmugam P, Ong G, Kamaruddin F, Tan S

Malays Orthop J, 2014 Mar;8(1):32-6.
PMID: 25347294 MyJurnal DOI: 10.5704/MOJ.1403.015

Patients with extensive malignancies involving the femur often require total femoral replacement when their limbs can be salvaged. Reported series are small and involve heterogeneity of tumours. We present nine patients with osteosarcomas of the femur treated at our institution between 2003 and 2010 with a mean follow-up of 27 (6 to 56) months. Their ages ranged from 9 to 17 (mean 14 years). They had large volume tumours (mean 911 cm3) and presented late with a mean of 5.5 months from the onset of symptoms to definitive treatment. All patients underwent resection and total femur replacement. Six patients have died and two are alive with good function at the time of this report. One was lost to follow-up. These patients require a high level of treatment care and have a guarded prognosis.
Fulltext Non-bacterial chronic recurrent osteomyelitis of the clavicle

Pan K, Chan W, Ong G, Zulqarnaen M, Norlida D

Malays Orthop J, 2012 Mar;6(1):57-60.
PMID: 25279046 MyJurnal DOI: 10.5704/MOJ.1203.005

This report details the case of a 12-year-old girl with a painful, progressive swelling of the medial portion of the clavicle with no history of trauma or other constitutional symptoms. All laboratory investigations were normal except for an elevated erythrocyte sedimentation rate (ESR). Initial plain radiographs showed a destructive lesion with magnetic resonance imaging showing features of malignancy. Biopsies revealed osteomyelitis, but with negative bacterial cultures and no evidence of malignancy. Treatment with antibiotics did not result in a favourable response. Over time, the swelling increased in size with episodic exacerbations of pain. Follow-up radiographs showed sclerosis and hyperostosis. After five years, this was recognized as non-bacterial chronic recurrent osteomyelitis of the clavicle.
Fulltext Intraosseous synovial sarcoma of the proximal femur: Case report

Zulkarnaen M, Pan K, Shanmugam P, Ibrahim Z, Chan W

Malays Orthop J, 2012 Mar;6(1):49-52.
PMID: 25279044 MyJurnal DOI: 10.5704/MOJ.1203.003

ABSTRACT: Synovial sarcoma is primarily a soft tissue malignancy that most often affects adolescents and young adults. It very rarely presents as a primary bone tumour and has only been reported in nine other cases to date. We report a case of primary synovial sarcoma arising from the proximal femur in a 57-year-old man.
KEY WORDS: Synovial sarcoma, primary bone tumour.
Extraskeletal myxoid chondrosarcoma of the thigh in a child: a case report

Ibrahim ZA, Chan WH, Wong SL, Ong EJ, Narihan MZ

J Orthop Surg (Hong Kong), 2014 Dec;22(3):423-6.
PMID: 25550031

Extraskeletal myxoid chondrosarcoma (EMC) is aggressive in children. The condition in children differs to that in adults and to skeletal myxoid chondrosarcoma. We report on a 9-year-old girl with EMC in her left thigh. She underwent above-knee amputation. Five months later, a small mass was noted at the right lower lobe of the lung. The patient underwent one course of ifosfamide, carboplatin, and etoposide chemotherapy, followed by resection of the mass and 8 more courses of chemotherapy. At the 2-year follow-up, she was in remission radiologically.
Fulltext A review of feature extraction software for microarray gene expression data

Tan CS, Ting WS, Mohamad MS, Chan WH, Deris S, Shah ZA

Biomed Res Int, 2014;2014:213656.
PMID: 25250315 DOI: 10.1155/2014/213656

When gene expression data are too large to be processed, they are transformed into a reduced representation set of genes. Transforming large-scale gene expression data into a set of genes is called feature extraction. If the genes extracted are carefully chosen, this gene set can extract the relevant information from the large-scale gene expression data, allowing further analysis by using this reduced representation instead of the full size data. In this paper, we review numerous software applications that can be used for feature extraction. The software reviewed is mainly for Principal Component Analysis (PCA), Independent Component Analysis (ICA), Partial Least Squares (PLS), and Local Linear Embedding (LLE). A summary and sources of the software are provided in the last section for each feature extraction method.
Fulltext Limb salvage in osteosarcoma using autoclaved tumor-bearing bone

Pan KL, Chan WH, Ong GB, Premsenthil S, Zulkarnaen M, Norlida D, et al.

World J Surg Oncol, 2012;10:105.
PMID: 22681750 DOI: 10.1186/1477-7819-10-105

Tumor prostheses currently give the best short- and medium-term results for limb-salvage reconstruction procedures in the treatment of bone tumors. However, in developing countries, the cost of a tumor prosthesis is beyond the reach of much of the population. We report the use of autoclaved tumor-bearing bone in 10 patients, as an affordable alternative to the use of prostheses.
Identification of informative genes and pathways using an improved penalized support vector machine with a weighting scheme

Chan WH, Mohamad MS, Deris S, Zaki N, Kasim S, Omatu S, et al.

Comput Biol Med, 2016 10 01;77:102-15.
PMID: 27522238 DOI: 10.1016/j.compbiomed.2016.08.004

Incorporation of pathway knowledge into microarray analysis has brought better biological interpretation of the analysis outcome. However, most pathway data are manually curated without specific biological context. Non-informative genes could be included when the pathway data is used for analysis of context specific data like cancer microarray data. Therefore, efficient identification of informative genes is inevitable. Embedded methods like penalized classifiers have been used for microarray analysis due to their embedded gene selection. This paper proposes an improved penalized support vector machine with absolute t-test weighting scheme to identify informative genes and pathways. Experiments are done on four microarray data sets. The results are compared with previous methods using 10-fold cross validation in terms of accuracy, sensitivity, specificity and F-score. Our method shows consistent improvement over the previous methods and biological validation has been done to elucidate the relation of the selected genes and pathway with the phenotype under study.
Fulltext Alteration of foot temperature in diabetic neuropathy: is it another piece of puzzle?

Naicker AS, Roohi SA, Lee CS, Chan WH, Tay LS, Din XJ, et al.

Med J Malaysia, 2006 Feb;61 Suppl A:10-3.
PMID: 17042221

Poor glycaemic control and the duration of diabetes mellitus are known to accelerate development and progression of neuropathy. Diabetic co-morbidities: hypertension and hyperlipidaemia, have been postulated to associate with development of neuropathy. A diabetic foot with low temperature and frequent exposure to low temperature environment has recently been hypothesized to be at higher risk to develop early neuropathy. This cross-sectional study is undertaken to identify risk factors for diabetic neuropathy and the association between foot temperature and development of diabetic neuropathy by using simple clinical examination in the outpatient setting. From April 18, to April 30, 2005, universal sampling method was used to select 134 diabetic patients (type 1 or type 2 for >1 year) with peripheral neuropathy. Excluded are those with chronic alcoholism, drug-induced neuropathy, dietary history of vitamin B deficiency and family history of porphyria and hereditary sensorimotor neuropathy. The patient's duration of diabetes, glycaemic control status and the presence of co-morbids: hypertension and hyperlipidemia, were recorded. The temperature of the foot was measured by using thermo buddy. Of 134 patients representing Malaysian ethnic distribution with an equal number of males and females, 20.1% were in the age group of 61 to 65 years and, 85.1% and 67.9% belonged to lower socioeconomic and educational groups respectively. Associations between diabetic neuropathy and glycaemic control (p = 0.018) and duration of diabetes (p < 0.05) were significant. However, hypertension, hyperlipidaemia and low foot temperature were not significantly associated with development of diabetic neuropathy. Poor glycaemic control is significantly associated with diabetic neuropathy. Foot temperature alteration is merely an effect of autonomic neuropathy with a cold foot is attributed to co-existing peripheral arterial disease.

Study site: Pusat Perubatan Primer Bandar Tasik Selatan, Kuala Lumpur, Malaysia
Fulltext Enhanced Directed Random Walk for the Identification of Breast Cancer Prognostic Markers from Multiclass Expression Data

Nies HW, Mohamad MS, Zakaria Z, Chan WH, Remli MA, Nies YH

Entropy (Basel), 2021 Sep 20;23(9).
PMID: 34573857 DOI: 10.3390/e23091232

Artificial intelligence in healthcare can potentially identify the probability of contracting a particular disease more accurately. There are five common molecular subtypes of breast cancer: luminal A, luminal B, basal, ERBB2, and normal-like. Previous investigations showed that pathway-based microarray analysis could help in the identification of prognostic markers from gene expressions. For example, directed random walk (DRW) can infer a greater reproducibility power of the pathway activity between two classes of samples with a higher classification accuracy. However, most of the existing methods (including DRW) ignored the characteristics of different cancer subtypes and considered all of the pathways to contribute equally to the analysis. Therefore, an enhanced DRW (eDRW+) is proposed to identify breast cancer prognostic markers from multiclass expression data. An improved weight strategy using one-way ANOVA (F-test) and pathway selection based on the greatest reproducibility power is proposed in eDRW+. The experimental results show that the eDRW+ exceeds other methods in terms of AUC. Besides this, the eDRW+ identifies 294 gene markers and 45 pathway markers from the breast cancer datasets with better AUC. Therefore, the prognostic markers (pathway markers and gene markers) can identify drug targets and look for cancer subtypes with clinically distinct outcomes.
Fulltext The COVID-19 Pandemic Situation in Malaysia: Lessons Learned from the Perspective of Population Density

Aw SB, Teh BT, Ling GHT, Leng PC, Chan WH, Ahmad MH

Int J Environ Res Public Health, 2021 Jun 18;18(12).
PMID: 34207205 DOI: 10.3390/ijerph18126566

This paper attempts to ascertain the impacts of population density on the spread and severity of COVID-19 in Malaysia. Besides describing the spatio-temporal contagion risk of the virus, ultimately, it seeks to test the hypothesis that higher population density results in exacerbated COVID-19 virulence in the community. The population density of 143 districts in Malaysia, as per data from Malaysia's 2010 population census, was plotted against cumulative COVID-19 cases and infection rates of COVID-19 cases, which were obtained from Malaysia's Ministry of Health official website. The data of these three variables were collected between 19 January 2020 and 31 December 2020. Based on the observations, districts that have high population densities and are highly inter-connected with neighbouring districts, whether geographically, socio-economically, or infrastructurally, tend to experience spikes in COVID-19 cases within weeks of each other. Using a parametric approach of the Pearson correlation, population density was found to have a moderately strong relationship to cumulative COVID-19 cases (p-value of 0.000 and R2 of 0.415) and a weak relationship to COVID-19 infection rates (p-value of 0.005 and R2 of 0.047). Consequently, we provide several non-pharmaceutical lessons, including urban planning strategies, as passive containment measures that may better support disease interventions against future contagious diseases.
A Review of Gene Knockout Strategies for Microbial Cells

Tang PW, Chua PS, Chong SK, Mohamad MS, Choon YW, Deris S, et al.

Recent Pat Biotechnol, 2015;9(3):176-97.
PMID: 27185502

BACKGROUND: Predicting the effects of genetic modification is difficult due to the complexity of metabolic net- works. Various gene knockout strategies have been utilised to deactivate specific genes in order to determine the effects of these genes on the function of microbes. Deactivation of genes can lead to deletion of certain proteins and functions. Through these strategies, the associated function of a deleted gene can be identified from the metabolic networks.
METHODS: The main aim of this paper is to review the available techniques in gene knockout strategies for microbial cells. The review is done in terms of their methodology, recent applications in microbial cells. In addition, the advantages and disadvantages of the techniques are compared and discuss and the related patents are also listed as well.
RESULTS: Traditionally, gene knockout is done through wet lab (in vivo) techniques, which were conducted through laboratory experiments. However, these techniques are costly and time consuming. Hence, various dry lab (in silico) techniques, where are conducted using computational approaches, have been developed to surmount these problem.
CONCLUSION: The development of numerous techniques for gene knockout in microbial cells has brought many advancements in the study of gene functions. Based on the literatures, we found that the gene knockout strategies currently used are sensibly implemented with regard to their benefits.

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