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Search Results: 1 - 10 of 596 matches for " Tun-Linn Thein "
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Utilities and Limitations of the World Health Organization 2009 Warning Signs for Adult Dengue Severity
Tun-Linn Thein equal contributor ,Victor C. Gan equal contributor,David C. Lye,Chee-Fu Yung,Yee-Sin Leo
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002023
Abstract: Background In 2009, the World Health Organization (WHO) proposed seven warning signs (WS) as criteria for hospitalization and predictors of severe dengue (SD). We assessed their performance for predicting dengue hemorrhagic fever (DHF) and SD in adult dengue. Method DHF, WS and SD were defined according to the WHO 1997 and 2009 dengue guidelines. We analyzed the prevalence, sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of WS before DHF and SD onset. Results Of 1507 cases, median age was 35 years (5th–95th percentile, 17–60), illness duration on admission 4 days (5th–95th percentile, 2–6) and length of hospitalization 5 days (5th–95th percentile, 3–7). DHF occurred in 298 (19.5%) and SD in 248 (16.5%). Of these, WS occurred before DHF in 124 and SD in 65 at median of two days before DHF or SD. Three commonest warning signs were lethargy, abdominal pain/tenderness and mucosal bleeding. No single WS alone or combined had Sn >64% in predicting severe disease. Specificity was >90% for both DHF and SD with persistent vomiting, hepatomegaly, hematocrit rise and rapid platelet drop, clinical fluid accumulation, and any 3 or 4 WS. Any one of seven WS had 96% Sn but only 18% Sp for SD. Conclusions No WS was highly sensitive in predicting subsequent DHF or SD in our confirmed adult dengue cohort. Persistent vomiting, hepatomegaly, hematocrit rise and rapid platelet drop, and clinical fluid accumulation, as well as any 3 or 4 WS were highly specific for DHF or SD.
Risk Factors for Fatality among Confirmed Adult Dengue Inpatients in Singapore: A Matched Case-Control Study
Tun-Linn Thein, Yee-Sin Leo, Dale A. Fisher, Jenny G. Low, Helen M. L. Oh, Victor C. Gan, Joshua G. X. Wong, David C. Lye
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0081060
Abstract: Objectives To identify demographic, clinical and laboratory risk factors for death due to dengue fever in adult patients in Singapore. Methods Multi-center retrospective study of hospitalized adult patients with confirmed dengue fever in Singapore between 1 January 2004 and 31 December 2008. Non-fatal controls were selected by matching age and year of infection with fatal cases. World Health Organization 1997, 2009 criteria were applied to define dengue hemorrhagic fever (DHF), warning signs and severe dengue. Statistical significance was assessed by conditional logistic regression modeling. Results Significantly more fatal cases than matched controls had pre-existing co-morbid conditions, and presented with abdominal pain/tenderness. Median pulse rates were significantly higher while myalgia was significantly less frequent in cases. . Fatal cases also had higher leucocyte counts, platelet counts, serum sodium, potassium, urea, creatine and bilirubin levels on admission compared to controls. There was no statistical significant difference between the prevalence of DHF and hematocrit level among cases and controls. Multivariate analysis showed myalgia and leucocyte count at presentation were independent predictors of fatality (adjusted odds ratios 0.09 and 2.94 respectively). None of the controls was admitted to intensive care unit (ICU) or given blood transfusion, while 71.4% and 28.6% of fatal cases received ICU admission and blood transfusion. Conclusions Absence of myalgia and leucocytosis on admission were independently associated with fatality in our matched case-control study. Fatalities were also commonly associated with co-morbidities and clinicians should be alarmed if dengue patients fulfilled severe dengue case definition on admission.
Challenges in Dengue Fever in the Elderly: Atypical Presentation and Risk of Severe Dengue and Hospita-Acquired Infection
Emily K. Rowe ,Yee-Sin Leo,Joshua G. X. Wong,Tun-Linn Thein,Victor C. Gan,Linda K. Lee,David C. Lye
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0002777
Abstract: Background/methods To better understand dengue fever in the elderly, we compared clinical features, World Health Organization (WHO) dengue classification and outcomes between adult (<60) and elderly (≥60) dengue patients. We explored the impact of co-morbidity and hospital-acquired infection (HAI) on clinical outcomes in the elderly. All patients managed at the Communicable Disease Centre, Singapore, between 2005 and 2008 with positive dengue polymerase chain reaction (PCR) or who fulfilled WHO 1997 or 2009 probable dengue criteria with positive dengue IgM were included. Results Of the 6989 cases, 295 (4.4%) were elderly. PCR was positive in 29%. The elderly suffered more severe disease with more dengue haemorrhagic fever (DHF) (29.2% vs. 21.4%) and severe dengue (SD) (20.3% vs. 14.6%) (p<0.05). Classic dengue symptoms were more common in the adult group. The elderly were less likely to fulfill WHO 1997 (93.6% vs. 96.4%) (p = 0.014), but not WHO 2009 probable dengue (75.3% vs. 71.5%). Time to dengue diagnosis was similar. There was no significant difference in the frequency of warning signs between the two groups, but the elderly were more likely to have hepatomegaly (p = 0.006) and malaise/lethargy (p = 0.033) while the adults had significantly more mucosal bleeding (p<0.001). Intensive care admission occurred in 15 and death in three, with no age difference. Notably, the elderly stayed in hospital longer (median 5 vs. 4 days), and suffered more pneumonia (3.8% vs. 0.7%) and urinary infection (1.9% vs. 0.3%) (p = 0.003). Predictors of excess length of stay were age (adjusted odds ratio [aOR] 2.01, 95% confidence interval [CI] 1.37–2.88), critical illness (aOR 5.13, 95%CI 2.59–9.75), HAI (aOR 12.06, 95%CI 7.39–19.9), Charlson score (aOR 6.9, 95%CI 2.02–22.56) and severe dengue (DHF/dengue shock syndrome/SD) (aOR 2.24, 95%CI 1.83–2.74). Conclusion Elderly dengue patients present atypically and are at higher risk of DHF, SD and HAI. Aside from dengue severity, age, co-morbidity and HAI were associated with longer hospital stay.
Predictive Value of Proteinuria in Adult Dengue Severity
Farhad F. Vasanwala equal contributor,Tun-Linn Thein equal contributor,Yee-Sin Leo ,Victor C. Gan,Ying Hao,Linda K. Lee,David C. Lye
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0002712
Abstract: Background Dengue is an important viral infection with different presentations. Predicting disease severity is important in triaging patients requiring hospital care. We aim to study the value of proteinuria in predicting the development of dengue hemorrhagic fever (DHF), utility of urine dipstick test as a rapid prognostic tool. Methodology and principal findings Adult patients with undifferentiated fever (n = 293) were prospectively enrolled at the Infectious Disease Research Clinic at Tan Tock Seng Hospital, Singapore from January to August 2012. Dengue infection was confirmed in 168 (57%) by dengue RT-PCR or NS1 antigen detection. Dengue cases had median fever duration of 6 days at enrolment. DHF was diagnosed in 34 cases according to the WHO 1997 guideline. Dengue fever (DF) patients were predominantly younger and were mostly seen in the outpatient setting with higher platelet level. Compared to DF, DHF cases had significantly higher peak urine protein creatinine ratio (UPCR) during clinical course (26 vs. 40 mg/mmol; p<0.001). We obtained a UPCR cut-off value of 29 mg/mmol based on maximum AUC in ROC curves of peak UPCR for DF versus DHF, corresponding to 76% sensitivity and 60% specificity. Multivariate analysis with other readily available clinical and laboratory variables increased the AUC to 0.91 with 92% sensitivity and 80% specificity. Neither urine dipstick at initial presentation nor peak urine dipstick value during the entire illness was able to discriminate between DF and DHF. Conclusions Proteinuria measured by a laboratory-based UPCR test may be sensitive and specific in prognosticating adult dengue patients.
Prevention and Treatment of Venous Thromboembolism with New Oral Anticoagulants: A Practical Update for Clinicians
Nay Min Tun,Thein Hlaing Oo
Thrombosis , 2013, DOI: 10.1155/2013/183616
Abstract:
Prevention and Treatment of Venous Thromboembolism with New Oral Anticoagulants: A Practical Update for Clinicians
Nay Min Tun,Thein Hlaing Oo
Thrombosis , 2013, DOI: 10.1155/2013/183616
Abstract: Traditional anticoagulants, such as warfarin and enoxaparin, have several limitations, including parenteral administration, need for laboratory monitoring, and ongoing dose adjustment, which may limit optimal patient care. Newer oral anticoagulants, such as direct thrombin inhibitors (e.g., dabigatran etexilate) and direct factor Xa inhibitors (e.g., rivaroxaban, apixaban, and edoxaban), have been developed to overcome these drawbacks, and thereby improve patient care. Several of these agents have been approved for use in the prevention and treatment of venous and/or systemic thromboembolism. The objective of this paper is to provide an overview of the available clinical trial data for these new oral anticoagulants in the prevention and treatment of venous thromboembolism and a practical update for clinicians. 1. Introduction Venous thromboembolism (VTE) comprises deep vein thrombosis (DVT) and pulmonary embolism (PE). Although the exact incidence of VTE is not known, it is estimated to affect 900,000 patients each year in the United States [1]. Approximately one-third of these cases are fatal pulmonary emboli, and the remaining two-thirds are nonfatal episodes of symptomatic DVT or PE [1]. VTE is the second most common cause of extended hospital stay and the third most common cause of in-hospital mortality [2]. Because it causes considerable morbidity and mortality, VTE places a substantial burden on healthcare resources [3, 4]. Without thromboprophylaxis, the incidence of hospital-acquired DVT based on objective diagnostic screening is 10–40% among medical or general surgical patients and 40–60% among patients who have undergone major orthopedic surgery such as total knee replacement (TKR), total hip replacement (THR), and hip fracture surgery [5]. Patients with cancer are at a greater risk of new or recurrent VTE than patients without cancer. VTE risk is 3- to 5-fold higher in cancer patients who are undergoing surgery and 6.5-fold higher in cancer patients receiving chemotherapy than in patients who do not have cancer [6, 7]. The efficacy of traditional anticoagulants in preventing VTE in patients undergoing major orthopedic surgery and in hospitalized acutely ill medical patients is well established [5, 8–11]. However, these agents have several limitations that may limit optimal patient care, such as their parenteral administration, need for laboratory monitoring, and ongoing dose adjustment (Table 1) [12–16]. Newer oral anticoagulants, such as direct thrombin inhibitors (e.g., dabigatran etexilate) and direct factor Xa inhibitors (e.g.,
250 MHz to 30 GHz, Unilateral Circuitmodel for Ingap/GaAs Hbt
Than Tun Thein;Choi Look Law;Kai Fu
PIER C , 2012, DOI: 10.2528/PIERC11101702
Abstract: A unilateral circuit model, which precisely predicts small signal response over a wide range of frequencies and bias points, is quantitatively analyzed and presented. The shortfall of current unilateral assumption and transformation technique is presented. A complete and explicit analysis is provided to develop a compact unilateral circuit model. The model is intended to predict input reflection, forward transmission and output reflection coefficients over wide range of frequencies. The technique is validated by transforming bilateral a small signal model of 3 x 3 μm x 40 μm, InGaP/GaAs HBT into its unilateral equivalent over the frequency range of 250 MHz to 30 GHz. The accuracy of the technique is corroborated at various bias conditions; collector current from 3 mA to 150 mA and collector-emitter voltage from 1 V to 5 V. Simulated results show very good agreement between small signal responses of transformed unilateral and bilateral circuit models.
Frequency Domain Dynamic Thermal Analysis in GaAs Hbt for Power Amplifier Applications
Than Tun Thein;Choi Look Law;Kai Fu
PIER , 2011, DOI: 10.2528/PIER11050301
Abstract: Dynamic temperature distributions in GaAs HBT are numerically analyzed in frequency domain as a function of power dissipation, frequency and space. Complete thermal characteristics, including frequency-dependent thermal impedance and phase lag behavior, are presented. The analysis is also extended for arbitrary periodic or aperiodic pulse heating operation to predict junction temperature of a Power Amplifier (PA) with non-constant envelope input signal. Dynamic junction temperatures of a single finger 2 μm x 20 μm GaAs HBT are predicted for square pulse envelope signal input with power levels varying with up to 10 dB above a nominal average level of 40 mW and with pulse widths ranging from 10 ns to 100 μs. With the input envelope signal amplitude of 10 dB above the average, the analytical results show that junction temperature rises from room temperature of 27C to 39C when heated by 10 ns pulse, increase to 36C by 100ns pulse, 105C by 1μs pulse and to 198C by 100 μs pulse. A novel setup is developed for nano-second pulsed measurements, and the analysis is validated through time domain on wafer pulsed measurements at three different power levels: 0 dB, 3 dB, and 6 dB above the average level. Results show that analytical results track well with measured junction temperature within the accuracy of ±5C over the entire measurement set.
Engineering Adaptive Digital Investigations using Forensics Requirements
Liliana Pasquale. Yijun Yu,Luca Cavallaro,Mazeiar Salehie,Thein Than Tun,Bashar Nuseibeh
Computer Science , 2014,
Abstract: A digital forensic investigation aims to collect and analyse the evidence necessary to demonstrate a potential hypothesis of a digital crime. Despite the availability of several digital forensics tools, investigators still approach each crime case from scratch, postulating potential hypotheses and analysing large volumes of data. This paper proposes to explicitly model forensic requirements in order to engineer software systems that are forensic-ready and guide the activities of a digital investigation. Forensic requirements relate some speculative hypotheses of a crime to the evidence that should be collected and analysed in a crime scene. In contrast to existing approaches, we propose to perform proactive activities to preserve important - potentially ephemeral - evidence, depending on the risk of a crime to take place. Once an investigation starts, the evidence collected proactively is analysed to assess if some of the speculative hypotheses of a crime hold and what further evidence is necessary to support them. For each hypothesis that is satisfied, a structured argument is generated to demonstrate how the evidence collected supports that hypothesis. Our evaluation results suggest that the approach provides correct investigative findings and reduces significantly the amount of evidence to be collected and the hypotheses to be analysed.
Implications of Discordance in World Health Organization 1997 and 2009 Dengue Classifications in Adult Dengue
Victor C. Gan, David C. Lye, Tun L. Thein, Frederico Dimatatac, Adriana S. Tan, Yee-Sin Leo
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060946
Abstract: Background Revised dengue guidelines were published by the World Health Organization (WHO) in 2009 addressing severe dengue cases not classified by dengue hemorrhagic fever (DHF) and shock syndrome (DSS). Methods and Principal Findings We conducted a retrospective cohort study to compare WHO 2009 and 1997 classifications using 1278 adult dengue cases confirmed by polymerase chain reaction assay from Singapore epidemics in 2004 and 2007 (predominantly serotype 1 and 2 respectively).DHF occurred in 14.3%, DSS 2.7% and severe dengue 16.0%. The two WHO dengue classifications were discordant in defining severe disease (p<0.001). Five DSS patients (15%) were classified as non-severe dengue without warning signs. Of severe dengue patients, 107 did not fulfil DHF criteria. Of these, 14.9% had self-resolving isolated elevated aminotransferases, 18.7% gastrointestinal bleeding without hemodynamic compromise and 56.1% plasma leakage with isolated tachycardia. We compared both guidelines against requirement for intensive care including the single death in this series: all six had severe dengue; only four had DHF as two lacked bleeding manifestations but had plasma leakage. Increasing length of hospitalization was noted among severe cases with both classifications but the trend was only statistically significant for WHO 2009. Length of hospitalization was significantly longer for severe plasma leakage compared with severe bleeding or organ impairment. Requirement for hospitalization increased using WHO 2009 from 17.0% to 51.3%. Conclusions While the WHO 2009 dengue classification is clinically useful, we propose retaining criteria for plasma leakage and hemodynamic compromise from WHO 1997, and refining definitions of severe bleeding and organ impairment to improve clinical relevance having found that differences in these accounted for the discordance between classifications. Findings from our retrospective study may be limited by the study site - a tertiary referral center in a hyperendemic country - and should be evaluated in a wider range of geographic settings.
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