Original Article

Chua SK, Selvanesan S, Sivalingam B, Chem YK, Norizah I, Zuridah H, Kumarasamy V, Chua KB
Correspondence: Dr Chua Kaw Bing, chuakawbing@yahoo.com.sg

ABSTRACT
Introduction During an outbreak from December 2004 to March 2005, 138 isolates of dengue virus were prospectively obtained from acute-phase serum samples of 1,067 patients with the provisional clinical diagnosis of acute dengue illness admitted to the adult wards of Hospital Tengku Ampuan Rahimah, Klang, Malaysia. Of the 138 dengue virus isolates, 87, 11, 24 and 3 were typed as dengue serotypes 1, 2, 3 and 4, respectively, by a commercial dengue virus typing kit using monoclonal antibodies (Mab). 13 dengue virus isolates could not be assigned to any specific serotype by serotyping Mab and molecular typing using dengue-type specific molecular typing primer pairs. We report the associated clinical features and limited molecular genetics of this Mab-escape dengue virus variant.
Methods Limited molecular characterisation of the Mab-escape dengue virus variants with respect to a few concurrently isolated dengue serotype 1 virus was performed by reverse transcriptase polymerase chain reaction (RT-PCR), followed by nucleic acid sequencing of the 500-bp dengue virus partial genomic capsid-PreM fragment.
Results The aligned nucleic acid sequence of RT-PCR products showed that these Mab-escape variants were of identical nucleic acid sequence, and shared the highest sequence homology (99 percent) with dengue virus serotype 1 (GeneBank accession No. AB178040) isolated from a Japanese patient in 2004. Though these Mab-escape dengue virus variants were noted to replicate to a 2-log higher titre than the current circulating dengue virus serotype 1, there was no significant difference between these variants and the currently circulating dengue virus serotype 1 with respect to disease severity (dengue fever versus dengue haemorrhagic fever) and clinical features.
Conclusion There was no significant difference in the proportion of patients developing dengue haemorrhagic fever following acute infection by Mab-escape dengue virus 1 variant in comparison with infection by the conventional dengue virus 1. Similarly, there was no significant difference in the pattern of clinical presentations following acute infection by the two different strains of virus.

Keywords: dengue haemorrhagic fever, dengue virus, molecular typing, monoclonocal antibody-escape variant
Singapore Med J 2006; 47(11): 940-946

Siti-Noor AS, Wan-Maziah WM, Narazah MY, Quah BS
Correspondence: Dr Siti-Noor Ali Shibramulisi, sitinooralishibramulisi@yahoo.co.uk

ABSTRACT
Introduction To determine the prevalence of iron deficiency (ID) and iron deficiency anaemia (IDA) in Kelantanese pre-school children and to identify risk factors that best predict the presence of ID.
Methods Children (aged eight to 26 months) who attended eight primary health clinics in the district of Kota Bharu, Kelantan, Malaysia, from September to November 1999, were invited to participate in the study. Parents were interviewed for potential risk factors of ID and blood was taken for the analysis of haemoglobin (HB), mean corpuscular volume and serum ferritin (SF) level after obtaining a verbal consent. The possible risk factors for ID were compared between the iron deficient (SF less than 12 microgrammes per litre) and iron sufficient (SF greater than 12 microgrammes per litre) groups using multiple logistic regression.
Results Among 490 children, 319 (65.1 percent, 95 percent confidence interval [CI] 60.7- 69.2 percent) had anaemia (HB less than 11.0 g/dL). 191 children (38.9 percent, 95 percent CI 34.7-43.5 percent) had ID. 155 children (31.6 percent, 95 percent CI 27.6-36.0 percent) had IDA (HB less than 11.0 g/dL and SF less than 12 microgrammes per litre). Independent risk factors for ID were prolonged breast feeding for more than six months (p-value is 0.003, adjusted odds ratio [OR] 2.5, 95 percent CI 1.5-4.0) and failure to receive formula milk (p-value is 0.004, adjusted OR 1.6, 95 percent CI 1.2-2.0). Other dietary factors were not significantly associated with ID.
Conclusion The prevalence of ID and IDA among Kelantanese children is high, and is mainly attributed to prolonged breast feeding beyond six months of age and failure to introduce formula milk at later infancy.

Keywords: anaemia, iron deficiency, iron deficiency anaemia, pre-school children
Singapore Med J 2006; 47(11): 935-939

Chan CH, Chan EY, Ng DK, Chow PY, Kwok KL
Correspondence: Dr Daniel K Ng, dkkng@ha.org.hk

ABSTRACT
Introduction Paediatric risk of mortality and paediatric index of mortality (PIM) are the commonly-used mortality prediction models (MPM) in children admitted to paediatric intensive care unit (PICU). The current study was undertaken to develop a better MPM using artificial neural network, a domain of artificial intelligence.
Methods The purpose of this retrospective case series was to compare an artificial neural network (ANN) model and PIM with the observed mortality in a cohort of patients admitted to a five-bed PICU in a Hong Kong non-teaching general hospital. The patients were under the age of 17 years and admitted to our PICU from April 2001 to December 2004. Data were collected from each patient admitted to our PICU. All data were randomly allocated to either the training or validation set. The data from the training set were used to construct a series of ANN models. The data from the validation set were used to validate the ANN and PIM models. The accuracy of ANN models and PIM was assessed by area under the receiver operator characteristics (ROC) curve and calibration.
Results All data were randomly allocated to either the training (n=274) or validation set (n=273). Three ANN models were developed using the data from the training set, namely ANN8 (trained with variables required for PIM), ANN9 (trained with variables required for PIM and pre-ICU intubation) and ANN23 (trained with variables required for ANN9 and 14 principal ICU diagnoses). Three ANN models and PIM were used to predict mortality in the validation set. We found that PIM and ANN9 had a high ROC curve (PIM: 0.808, 95 percent confidence interval 0.552 to 1.000, ANN9: 0.957, 95 percent confidence interval 0.915 to 1.000), whereas ANN8 and ANN23 gave a suboptimal area under the ROC curve. ANN8 required only five variables for the calculation of risk, compared with eight for PIM.
Conclusion The current study demonstrated the process of predictive mortality risk model development using ANN. Further multicentre studies are required to produce a representative ANN-based mortality prediction model for use in different PICUs.

Keywords: artificial neural network, intensive care unit, mortality prediction models, paediatric intensive care unit, predictive mortality risk model
Singapore Med J 2006; 47(11): 928-934

Lo HY, Leong CSL
Correspondence: Dr Lo Hong Yee, lohongyee@yahoo.com

ABSTRACT
Introduction There were anecdotal reports of an increase in the admissions of parenteral Subutex abusers to our hospital over the past five months. This case study aimed to analyse the surgical complications related to parenteral Subutex abuse and describe the demographics of this group of patients.
Methods We reviewed all admissions to our hospital between July and November 2005. Only parenteral Subutex abusers were included in this case study.
Results A total of 53 parenteral Subutex abusers were admitted during this period. 31 had surgical complications, while 22 presented with medical ones. Of the surgical patients, 12 had cellulitis and thrombophlebitis, six developed abscesses of the limbs, ten were patients with ischaemia and gangrene of the digits and limbs, one had septic arthritis, one had necrotising fasciitis, and one had a pseudoaneurysm of the femoral artery. There were no reported mortalities. Only nine patients needed surgical interventions. Most of the patients are young with a mean age of 34.2 years. There was a male predominance of 92.4 percent (49 out of 53). Malays are more frequently affected (72 percent, n=38), followed by Indians (15 percent, n=8), and Chinese (13 percent, n=7).
Conclusion Parenteral Subutex abuse is a rising concern in Singapore. Many patients present to the surgical and orthopaedic departments for limb and vascular complications. Surgery has a limited role in their management, and most are treated conservatively and expectantly. The solution to this emerging trend requires inter-hospital and ministerial collaboration.

Keywords: buprenorphine, drug abuse, opiate dependence, parenteral injection complications, substance abuse complications, Subutex
Singapore Med J 2006; 47(11): 924-927

Noor Zairul M, Khairul Faizi A
Correspondence:  Dr Noor Zairul Muhamad, drnzm71@yahoo.com

ABSTRACT
Introduction The purpose of this study is to assess whether the newly-developed VBM (Medizintechnik GmbH, Sulz, Germany) laryngeal tube (LT) is able to provide adequate ventilation and oxygenation to patients with an unstable neck and require airway management. The haemodynamic responses to insertion between the two devices were also studied. We compared the LT to the laryngeal mask airway (LMA) as an alternative airway management tool in adult patients with unstable neck and who underwent intubation with manual in-line neck stabilisation.
Methods A randomised single-blinded prospective study was conducted involving a total of 40 American Society of Anesthesiology I and II pre-medicated patients who were divided into two groups, LT or LMA, for airway management during elective surgery. There were 20 patients for each group. After pre-oxygenation, anaesthesia was induced using intravenous (i.v.) fentanyl and i.v. propofol. The neuromuscular blockade was produced with either i.v. vecuronium or i.v. atracurium. The LT or LMA was inserted after neuromuscular blockade was confirmed using a peripheral nerve stimulator (train-of-four 1). A size 3, 4 or 5 LT or a size 3 or 4 LMA was inserted while the patient's head and neck were being stabilised by an assistant who held the sides of the neck and the mastoid processes (manual in-line stabilisation). If it was not possible to ventilate the lungs, or if end-tidal carbon dioxide and/or chest movement did not indicate a patent airway, the LT or LMA was removed. After three failed attempts, the study was terminated and the airway was secured in the most suitable manner determined by the anaesthetist. After successful placement of LT or LMA, anaesthesia was maintained with 66 percent nitrous oxide in oxygen and 2 minimum alveolar concentration sevoflurane. All patients received standard anaesthesia monitoring. The ease of insertion, the number of attempts needed to successfully secure the airway, episodes of desaturation (less than 95 percent) and end-tidal carbon dioxide at various time intervals were studied. The haemodynamic parameters such as systolic blood pressure, diastolic blood pressure, mean arterial pressure and heart rate at different time intervals were also studied.
Results The study showed a statistically significant difference in time required for successful insertion between the groups; time required for LT was 24.8 +/- 7.7 seconds and LMA was 36.1 +/- 17.3 seconds (p-value equals 0.01). Both groups had no statistical differences (p-value is greater than 0.05) in number of attempts needed to achieve a patent airway, and the successful insertion rate was 100 percent for both groups. There were also no statistical differences in the haemodynamic response to insertion and the end-tidal carbon dioxide in this study.
Conclusion We conclude that, under anaesthesia, the LT was a valuable and better alternative to LMA for ventilation and airway management when the patient's head and neck are stabilised by the manual in-line method.

Keywords: airway management, anaesthetic equipment, cardiovascular system, difficult intubation, laryngeal mask, laryngeal tube
Singapore Med J 2006; 47(10): 892-896

Tan HH, Wong ML, Chan RKW
Correspondence:  Dr Tan Hiok Hee, hhtan@nsc.gov.sg

ABSTRACT
Introduction This study was conducted to determine the disease patterns of sexually transmitted infections (STI) in older men, as well as to gather information on their knowledge, attitudes, beliefs and sexual practices.
Methods A prospective study was carried out from January to June 2005 in men aged 50 years or older who attended the Department of STI Control clinic.
Results There were 104 men enrolled. The majority (92.3 percent) were Chinese, and 62.5 percent were aged between 50 and 59 years, 25.9 percent between 60 and 69 years, and 11.5 percent aged 70 years or older. The patients were predominantly heterosexual, and had fairly low levels of education--85.6 percent of the patients had received primary or secondary school level of education. Majority (79.8 percent) of the men had been sexually active in the preceding six months, and 37.3 percent had paid sex during that time. 29.8 percent of men reported having taken drugs such as sildenafil (Viagra, Pfizer, New York, NY, USA) or similar drugs such as vardenafil (Levitra, Bayer, Wuppertal, Germany) or tadalafil (Cialis, Eli Lilly, Indianapolis, IN, USA). 56.7 percent of the men had active infections, with non-gonococcal urethritis (15.4 percent), genital warts (12.5 percent) and gonorrhoea (10.6 percent) being the commonest. Generally, condom usage was accepted as an effective way to prevent transmission of STI. However, many of the men surveyed felt that condom usage reduced their sexual pleasure, and 38.5 percent felt that condoms were inconvenient. There were also areas of human immunodeficiency virus (HIV) knowledge that were lacking. Most patients listed the media as their main source of knowledge about STI and HIV.
Conclusion Older males attending the clinic remain at significant risk of STI and targeted educational efforts are warranted.

Keywords: condom, epidemiology, genital warts, gonorrhoea, non-gonococcal urethritis, sexually transmitted diseases
Singapore Med J 2006; 47(10): 886-891

Chong SA, Vaingankar JA, Chan YH, Jauhar N, Kwok V, Soo SC, Tan L, Verma S
Correspondence: Dr Siow-Ann Chong, siow_ann_chong@imh.com.sg

ABSTRACT
Introduction This study evaluated the quality of care in an early psychosis intervention programme (EPIP), as compared to standard treatment received by patients prior to the inception of the programme.
Methods The medical records of 50 patients with first-episode psychosis (FEP) who received psychiatric treatment in the calendar year of 2000, i.e. prior to the implementation of EPIP, and 87 FEP patients who were accepted in the EPIP, were reviewed for a period of one year. These patients were aged between 18 and 40 years. Each medical record was reviewed for a list of process indicators, which were identified from the published literature and other treatment guidelines, and covered different domains.
Results None of the pre-EPIP patients met all the 13 process indicators, whereas 48 percent of EPIP patients met all the indicators (p-value is less than 0.001). Using the default rate as a proxy of outcome, we found that 19 percent of EPIP patients had defaulted at the end of one year, whereas the default rate was 52 percent for the pre-EPIP patients (p-value is less than 0.001).
Conclusion It is possible to improve the quality of care in patients with FEP through the use of treatment guidelines, regular monitoring of symptoms and side effects, and periodic audits.

Keywords: process indicators, psychosis, quality of care, treatment guidelines
Singapore Med J 2006; 47(10): 882-885

BaHammam A, Bin Saeed A, Al-Faris E, Shaikh S
Correspondence: Dr Ahmed BaHammam, ashammam2@yahoo.com

ABSTRACT
Introduction This study was conducted to estimate sleep duration in Saudi elementary school children, sleep habits and practices that may affect it, and compare our results to published data in other societies.
Methods Parents of elementary school children were surveyed regarding their children's bedtime, rise time, sleep duration at night and daytime nap duration during weekdays and weekends. A questionnaire inquiring about demographical data, specific sleep problems and habits, and home environment was completed by the parents.
Results The study comprised 511 (50.5 percent) boys and 501 (49.5 percent) girls. During weekdays, bedtime for the whole group was 21.3 +/- 1.8 hours, rise time was 5.9 +/- 0.5 hours, total sleep time (TST) was 8.4 +/- 1.1 hours, and TST and nap was 9.98 +/- 1.3 hours. Multivariate analysis revealed that TST was affected by regularity of bedtime, mother's level of education, daytime naps, and the habits of watching television (TV) and playing computer games after 20.00 hours.
Conclusion Nighttime sleep duration is shorter in Saudi school children compared to published data. Several factors appeared to affect sleep duration, including mother's educational level, daytime naps and watching TV at night.

Keywords: children, elementary school, primary school, sleep, sleep duration
Singapore Med J 2006; 47(10): 875-881

Lee LK, Chen PCY, Lee KK, Kaur J
Correspondence: Dr Lee Lai Kah, laikah_lee@imu.edu.my

ABSTRACT
Introduction The onset of menstruation is part of the maturation process. However, variability in menstrual cycle characteristics and menstrual disorders are common. The purpose of this study was to determine the menstrual characteristics of adolescent females and factors associated with it.
Methods This is a cross-sectional descriptive study carried out on 2,411 secondary school adolescent females in Negeri Sembilan, Malaysia. Data were collected using a self-administered structured questionnaire on menstruation in Bahasa Malaysia.
Results Abnormal cycle length (menstrual cycle longer than 35 days or cycle length between 14 to 20 days or irregular pattern) was common and affected 37.2 percent of subjects. The majority (74.6 percent) experienced premenstrual syndrome and 69.4 percent had dysmenorrhoea. About 18 percent reported excessive menstrual loss (use two pads at a time to prevent blood from soaking through or confirmed by doctor to be anaemic due to heavy menstrual flow). Only 11.1 percent of schoolgirls seeked medical consultation for their menstrual disorders. Mothers remained the most important source of information (80 percent). Menstrual disorders were significantly more common in female adolescents who smoke and have suicidal behaviours (p-value is less than 0.05).
Conclusion Menstrual problems among adolescent female are common. They are influenced by certain modifiable factors.

Keywords: adolescents, dysmenorrhoea, female adolescents, menstruation, premenstrual syndrome
Singapore Med J 2006; 47(10): 869-874

Balasubramaniyan V, Nalini N
Correspondence:  Dr. Namasivayam Nalini, nalininam@yahoo.com

ABSTRACT
Introduction This study aimed to assess the leptin dependent changes on adenosine triphosphatase (ATPase) activities of the central nervous system during chronic ethanol supplementation.
Methods The mice were divided into four groups. Group 1 consisted of control animals that received isocaloric glucose, Group 2 animals received isocaloric glucose plus exogenous mouse recombinant leptin (230 microgrammes/kilogramme body weight intraperitoneally) every alternate day, Group 3 were alcohol-fed mice (6.32 grammes/kilogramme body weight orally), and Group 4 were alcohol-fed mice that received leptin (230 microgrammes/kilogramme body weight intraperitoneally) every alternate day. The experiment was terminated after giving the mice leptin injections for 15 days.
Results Ethanol feeding for a total period of 45 days (p-value is less than 0.05) significantly elevated the brain lipid hydroperoxide levels and total ATPases, sodium, potassium-ATPase and magnesium-ATPase activities but significantly decreased the calcium-ATPase activity. Leptin injections to ethanol-fed animals further elevated the levels of lipid hydroperoxides, total ATPases, sodium, potassium-ATPase and magnesium-ATPase, while calcium-ATPase activity was reduced significantly.
Conclusion Leptin plays an important role in the pathogenesis of ethanol-induced neurotoxicity by enhancing brain lipid peroxidation and regulating brain ATPase activities in mice. Thus, hyperleptinaemia-induced oxidative stress and enhanced ATPase activities may be important pathogenic factors in brain toxicity.

Keywords: adenosine triphosphatase, brain, ethanol, leptin, lipid peroxidation, mice, neurotoxicity
Singapore Med J 2006; 47(10): 864-868