Original Article

Jamshidi N, Rostami M, Najarian S, Menhaj MB, Saadatnia M, Firooz S
Correspondence: Dr Mostafa Rostami, nima_jamshidi@yahoo.com

ABSTRACT
Introduction This paper deals with the dynamic modelling of human walking. The main focus of this research was to optimise the function of the orthosis in patients with neuropathic feet, based on the kinematics data from different categories of neuropathic patients.
Methods The patient’s body on the sagittal plane was modelled for calculating the torques generated in joints. The kinematics data required for mathematical modelling of the patients were obtained from the films of patients captured by high speed camera, and then the films were analysed through a motion analysis software. An inverse dynamic model was used for estimating the spring coefficient.
Results In our dynamic model, the role of muscles was substituted by adding a spring-damper between the shank and ankle that could compensate for their weakness by designing ankle-foot orthoses based on the kinematics data obtained from the patients. The torque generated in the ankle was varied by changing the spring constant. Therefore, it was possible to decrease the torque generated in muscles which could lead to the design of more comfortable and efficient orthoses.
Conclusion In this research, unlike previous research activities, instead of studying the abnormal gait or modelling the ankle-foot orthosis separately, the function of the ankle-foot orthosis on the abnormal gait has been quantitatively improved through a correction of the torque.

Keywords: ankle-foot orthosis, gait analysis, Guillan-Barré syndrome, steppage gait
Singapore Med J 2009; 50(4): 412-417

Vandevenne JE, Lincoln T, Butts Pauly K, Rinsky L, Lang PK
Correspondence: Dr Jan E Vandevenne, vdvennej@hotmail.com

ABSTRACT
Introduction This study aimed to describe the radiological aspects and procedural steps of magnetic resonance (MR) imaging-guided closed reduction for the treatment of developmental dysplasia of the hip (DDH).
Methods Infants were positioned on a custom-made hip spica table attached to a vertically open double doughnut-shaped MR imaging unit (GE Signa SP, 0.5T) affording access to one orthopaedic surgeon and one radiologist. Standard MR imaging sequences and rapid dynamic MR imaging sequences, including fast spin-echo, fast gradient-echo and a fluoroscopic echo-planar sequence, were available. Procedural steps were described and illustrated as a guide for the radiologist actively collaborating with the orthopaedic surgeon.
Results Five separate procedural steps were defined, describing the imaging action and the radiologist’s focus related to the clinical action. These procedural steps included patient positioning, static imaging to evaluate hip congruency and factors impeding reduction, dynamic stress testing and reducing the hip while using dynamic motion MR imaging sequences to visualise reduction or dislocation, cast application with intermittent imaging confirmation of the femoral head position, and postprocedural static imaging.
Conclusion The role of the radiologist was well-defined during each procedural step of the MR imaging-guided closed reduction focusing on the use of specific sequences and image interpretation. Knowledge of these procedural steps may be helpful for efficient collaboration with the orthopaedic surgeon and successful MR imaging-guided treatment of DDH.

Keywords: closed hip joint reduction, developmental dysplasia of the hip, hip dislocation, imaging-guided closed reduction, magnetic resonance imaging-guided procedure
Singapore Med J 2009; 50(4): 407-411

Eng CW, Wansaicheong G, Goh SKJ, Earnest A, Sum C
Correspondence: Dr Eng Chee Way, engcheeway@yahoo.com.sg

ABSTRACT
Introduction The aim of our study was to determine the accuracy of the D-dimer test in the exclusion of pulmonary embolism.
Methods In 2006, 446 patients at our hospital underwent computed tomography pulmonary angiogram (CTPA) for the exclusion of pulmonary embolism. We selected patients with a clinical suspicion of pulmonary embolism, and who underwent both a CTPA examination and a D-dimer test performed within a period of five days. Pregnant women, patients with an allergy to intravenous contrast and those who were on anticoagulant therapy were excluded. Based on our criteria, 219 cases were selected. D-dimer test was performed using an immunoturbidimetric assay. A cut-off value of 500 ng/ml was selected as the upper limit to exclude thrombosis.
Results There were 42 patients positive for pulmonary embolism on CTPA and all had elevated D-dimer values. There were 177 patients negative for pulmonary embolism on CTPA and 49 of them had normal D-dimer values. The sensitivity and specificity of the D-dimer test was 100.0 percent (95 percent confidence interval [CI] 91.6–100.0) and 27.7 percent (95 percent CI 21.2–34.9), respectively. The likelihood ratio for a positive test and negative test was 1.38 and 0, respectively.
Conclusion The D-dimer test is suitable for screening patients with a clinical suspicion of pulmonary embolism. The indiscriminate use of CTPA results in unnecessary testing and elevates healthcare costs. Clinicians are urged to give due consideration to a D-dimer test result prior to requesting a CTPA examination.

Keywords: computed tomography pulmonary angiogram, D-dimer, pulmonary angiogram, pulmonary embolism
Singapore Med J 2009; 50(4): 403-406

Kazerani H, Hajimoradi B, Amini A, Naseri MH, Moharamzad Y
Correspondence: Dr Yashar Moharamzad, yasharpop@hotmail.com

ABSTRACT
Introduction This study aimed to evaluate the response rate, clinical efficacy and onset of action of sublingual captopril in patients diagnosed with hypertensive urgency.
Methods In this cross-sectional study, 101 (67 female and 34 male) patients with a diagnosis of hypertensive urgency (systolic pressure greater than or equal to 180 mmHg and/or diastolic pressure greater than or equal to 110 mmHg, and no findings of target organ damage) were included. Sublingual captopril (25 mg) was administered and the blood pressure was measured during a follow-up period of 120 minutes.
Results After 60 minutes, an ideal decrease (25 percent of the initial blood pressure) was detected in 54 patients (53.5 percent). An additional 25 mg of sublingual captopril was administered to the remaining 47 patients (46.5 percent). Of these, 19 (18.8 percent) did not respond even to the second dose of sublingual captopril. These non-responders consisted of patients who were taking multidrug antihypertensive regimens before presentation due to hypertensive urgency. No serious side effect was recorded during the study period.
Conclusion Sublingual captopril can be used as an effective, easily applicable and safe treatment in the management of hypertensive urgency for 120 minutes for those who do not receive multidrug antihypertensive regimens.

Keywords: captopril, hypertension, hypertensive urgency, sublingual captopril
Singapore Med J 2009; 50(4): 400-402

Chogtu B, Singh NP, Chawla S, Gupta U
Correspondence: Dr Bharti Chogtu, bhartimagazine@gmail.com

ABSTRACT
Introduction Diabetes mellitus is a common disorder associated with a number of metabolic abnormalities such as insulin resistance, dyslipidaemia and high blood pressure. These abnormalities are recognised risk factors for cardiovascular diseases. Insulin-sensitising drugs exert an effect on these cardiovascular risk factors. The present study was done with the objective of elucidating the differences in glycaemic control, plasma lipid levels and blood pressure in diabetic patients who were prescribed glitazones in combination with sulphonylureas.
Methods Patients were randomly assigned to receive either pioglitazone or rosiglitazone in addition to glimepiride in an open-labelled study. Fasting and postprandial blood glucose levels, glycosylated haemoglobin, fasting lipid profile and blood pressure were recorded at baseline and at various intervals until the end of the study period at 12 weeks.
Results A total of 56 patients (28 in the pioglitazone group and 28 in the rosiglitazone group) completed the study. There was no significant difference in the baseline values of various parameters between the two treatment groups. The efficacy of the two treatment groups was similar in terms of the maintenance of blood glucose levels (fasting blood glucose, p-value is 0.10; postprandial blood glucose, p-value is 0.95; glycosylated haemoglobin, p-value is 0.30) and the effect on blood pressure (systolic blood pressure, p-value is 0.45; diastolic blood pressure, p-value is 0.95), while the pioglitazone group showed significantly better efficacy in improving the lipid profile compared to the rosiglitazone group (total cholesterol, p-value is 0.002; triglycerides, p-value is 0.002; low density lipoprotein, p-value is 0.005; and high density lipoprotein, p-value is 0.43).
Conclusion The two drugs showed a similar effect on blood glucose levels and blood pressure. However, the pioglitazone group was superior to the rosiglitazone group in improving the lipid profile.

Keywords: blood pressure, diabetes mellitus, glimepiride, lipid profile, pioglitazone, rosiglitazone
Singapore Med J 2009; 50(4): 395-399

Termizy HM, Mafauzy M
Correspondence: Prof Mafauzy Mohamed, mafauzy@kb.usm.my

ABSTRACT
Introduction The increased prevalence of metabolic syndrome worldwide is closely related to the rising obesity epidemic. The objectives of the study were to determine the prevalence and identify the associated and prognostic factors that influence the risk of metabolic syndrome among obese patients attending the Obesity Clinic at Hospital Universiti Sains Malaysia.
Methods A study was conducted involving 102 obese persons who attended the Obesity Clinic from January 1 to December 31, 2005. Metabolic syndrome was defined according to the International Diabetes Federation criteria.
Results The overall prevalence of metabolic syndrome among obese patients was 40.2 percent. The prevalence was higher in females (43.7 percent) than in males (32.3 percent). The prevalence of metabolic syndrome was noted to increase with increasing body mass index class, from class 1 to class 2. However, the prevalence was lower in obesity class 3. The prevalence of metabolic comorbidities of raised blood pressure, reduced high density lipoprotein, high triglyceride and raised fasting blood glucose was 42, 40, 36 and 17 percent, respectively. A quarter of obese patients in this study had no other comorbidity. Based on logistic regression multivariable analysis, age was the only significant associated factor that influenced the risk of having metabolic syndrome.
Conclusion The prevalence of metabolic syndrome was high and the highest comorbidity was high blood pressure. Age was the only significant risk factor of having this syndrome.

Keywords: blood glucose, high density lipoprotein, metabolic syndrome, obesity, triglycerides
Singapore Med J 2009; 50(4): 390-394

Ng TH, How SH, Amran AR, Razali MR, Kuan YC
Correspondence: Dr Ng Teck Han, ngteckhan@hotmail.com

ABSTRACT
Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative bacillus. Melioidosis can affect many organs, including the prostate. However, prostatic abscess due to melioidosis is uncommon. We describe five cases of melioidosis with prostatic abscess. Four of five patients had diabetes mellitus and had more than one organ involvement. The diagnosis of prostatic abscess in our patients was only made with computed tomography of the abdomen and pelvis. None of our patients underwent surgical drainage and all remained well after treatment with antibiotics, except for one mortality secondary to severe septicaemia.

Keywords: Burkholderia pseudomallei, melioidosis, melioidotic prostatic abscess, prostatic abscess
Singapore Med J 2009; 50(4): 385-389

Boonsarngsuk V, Tansirichaiya K, Kiatboonsri S
Correspondence: Dr Viboon Boonsarngsuk, bss-vb@hotmail.com

ABSTRACT
Introduction This study aimed to determine the prevalence and risk factors of drug-resistant tuberculosis (TB), and to develop a diagnostic algorithm for newly-diagnosed TB patients.
Methods This is a retrospective medical chart review of 290 patients who were diagnosed with bacteriological-proven pulmonary TB between 2000 and 2006 in Ramathibodi Hospital, Thailand. Patient characteristics, radiological and microbiological findings, as well as a history of previous TB disease and treatment, were included in the analysis of predictive factors of drug resistance. Predictive scores were derived from statistically significant factors at the cut-off point of the receiver-operating curve that yielded the best area under the curve.
Results The resistance rate to each of these drugs among 290 patients was: isoniazid, 6.9 percent; rifampicin, 4.5 percent; either isoniazid or rifampicin, 9.0 percent; and multidrug resistance, 2.4 percent. Far advanced TB was an independent risk factor for isoniazid resistance. Rifampicin resistance was associated with recurrent TB within six months after the completion of treatment and prior incomplete TB treatment. A drug-resistant TB predictive score of either isoniazid or rifampicin resistance was developed based on the aforementioned factors. The cut-off score of greater than or equal to 3 yielded the least error of classification in differentiating patients with the resistant strain from those with the susceptible strain at a sensitivity of 57.7 percent, a specificity of 67.8 percent, a positive predictive value of 15 percent and a negative predictive value of 94.2 percent.
Conclusion Our study suggested a drug-resistant TB predictive score for the exclusion of either isoniazid or rifampicin resistance, and provides a decisional guide for the clinician on whether to send a patient’s respiratory specimen for sputum culture and drug susceptibility testing.

Keywords: drug-resistant tuberculosis, drug susceptibility testing, tuberculosis
Singapore Med J 2009; 50(4): 378-384

Hsien YC, Abdullah MS, Telesinghe PU, Ramasamy R
Correspondence: Prof Ranjan Ramasamy, ramasamy@im.ubd.edu.bn

ABSTRACT
Introduction Little or no information is available on the prevalence of nasopharyngeal carcinoma (NPC) among different ethnic groups in Brunei, or how useful plasma IgA antibodies are against viral capsid antigen (VCA) and early antigen (EA) in the diagnosis of NPC, even though they are routinely measured in patients suspected to have NPC.
Methods The National Cancer Registry at Raja Isteri Pengiran Anak Saleha (RIPAS) Hospital was used to identify NPC patients diagnosed between 2000 and 2006. Clinical data and antibody test results for 38 NPC patients and for nine patients suspected of NPC but later diagnosed as negative for NPC by biopsy (control group) were obtained from the Oncology and Histopathology Departments at RIPAS Hospital.
Results The annual incidence rates for NPC among the major ethnic groups in Brunei were determined and compared to data from Singapore and Peninsular Malaysia. The most significant finding was that the average annual incidence of NPC among Bruneian Chinese males (4.1 per 100,000 persons) was significantly lower than that for Chinese males from Singapore (15.9) and Peninsular Malaysia (19.6). IgA anti-VCA and IgA anti-EA were sensitive and specific to NPC in Brunei in accordance with studies elsewhere. The measurement of IgA antibodies against VCA by ELISA was the better serological test for NPC. However, many stage IV NPC cases did not possess IgA anti-VCA and IgA anti-EA.
Conclusion Determining the factors that are responsible for a lower incidence of NPC among Chinese males in Brunei Darussalam may be useful for formulating measures to reduce NPC incidence elsewhere. The possible tendency for the loss of IgA antibodies against VCA and EA in advanced stages of NPC needs to be established with a larger number of patients, and the causes elucidated, in order to better understand the disease process in NPC.

Keywords: cancer biomarkers, cancer epidemiology, Epstein-Barr virus antigens, IgA antibodies, nasopharyngeal carcinoma
Singapore Med J 2009; 50(4): 371-377

Chan A, Lim LLC, Tao M
Correspondence: Dr Alexandre Chan, phaac@nus.edu.sg

ABSTRACT
Introduction Recombinant erythropoietin-stimulating agents have been used to ameliorate the symptoms of anaemia in cancer patients. However, there have been concerns about an increased risk of thromboembolic events and mortality. This study reviews the usage of epoetin alfa in treating chemotherapy-induced anaemia at the National Cancer Centre Singapore (NCCS), as well as the prescribing and monitoring practices employed.
Methods Cancer patients who have received at least one dose of epoetin alfa at the NCCS between January 1, 2005 and October 15, 2007 were included in this study.
Results A total of 121 patients were identified and 91 patients were eligible for data collection. The majority of patients manifested breast cancer (30.8 percent) and ovarian cancer (15.4 percent). Over 90 percent of the patients were receiving either chemotherapy or radiotherapy when epoetin alfa was initiated. Epoetin alfa was initiated at a median haemoglobin level of 8.7 (range 7–14.3) g/dL. Approximately 41.8 percent of the patients had a positive response after the initiation of epoetin alfa. Baseline iron studies were performed in 12.1 percent of the patients. Blood pressure was uncontrolled, according to the Singapore Ministry of Health Hypertension guideline, in a substantial number of patients (32.6 percent) prior to the initiation epoetin alfa. There were no documented thromboembolic events.
Conclusion This study identified a broad range of practices in the utilisation of epoetin alfa at NCCS, which may explain the variable patient response to epoetin alfa. The results of this study will be used to improve the management of chemotherapy-induced anaemia at the institution.

Keywords: anaemia, cancer, epoetin alfa, erythropoietin-stimulating agent, recombinant erythropoietin-stimulating agent
Singapore Med J 2009; 50(4): 365-370