Gita Krishnaswamy

Determinants of Anterior Chamber Depth: The Singapore Chinese Eye Study

PURPOSE Recent advances in anterior segment imaging have enabled the measurement of novel ocular biometric parameters, such as lens vault (LV), posterior corneal arc length (PCAL), and iris area. The aims of this study were to identify the determinants of anterior chamber depth (ACD) and to ascertain the relative importance of these determinants in Chinese persons in Singapore. DESIGN Population-based, cross-sectional study. PARTICIPANTS One thousand sixty Chinese participants recruited from the Singapore Chinese Eye Study. METHODS All subjects underwent AS optical coherence tomography (OCT; Carl Zeiss Meditec, Dublin, CA). Customized software (Zhongshan Angle Assessment Program, Guangzhou, China) was used to measure the AS-OCT parameters. Anterior chamber depth was determined using IOLMaster (Carl Zeiss Meditec). Univariate and multivariate regression analyses were performed to assess the association between ACD with ocular biometric and systemic parameters. A stepwise selection algorithm was used to identify sequentially the contribution of each independent variable. MAIN OUTCOME MEASURES Anterior chamber depth and ocular biometric parameters. RESULTS The mean age (±standard deviation) of participants was 56.9±8.57 years and 50.5% were men. The mean ACD was 3.24±0.35 mm. The strongest determinants of ACD were LV (R(2) = 0.582; P<0.001) and PCAL (partial R(2) = 0.186; P<0.001). For every 10-μm increase in LV and every 1-mm increase in PCAL, ACD changed by -0.008 mm (95% confidence interval [CI], -0.009 to -0.008 mm; P<0.001) and 0.525 mm (95% CI, 0.468-0.583 mm; P<0.001), respectively. The 8 most highly associated variables (including LV, PCAL, axial length, age, and iris area) explained 80.5% of the variability in ACD, but when excluding LV and PCAL, the other 6 variables explained only 3.7% of the variability in ACD. After controlling for LV and PCAL, axial length was a poor determinant of ACD (partial R(2) = 0.006), whereas lens thickness was not associated independently with ACD. CONCLUSIONS Lens vault and PCAL explained 76.8% of the variability in ACD. When information about LV and PCAL were available, axial length was a poor determinant of ACD, whereas lens thickness was not associated independently with ACD. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Depression and anxiety in Singaporean high-risk pregnancies - prevalence and screening

OBJECTIVE Data on psychiatric morbidity in high-risk pregnant Singaporean women are limited. This study aimed to establish the prevalence of antenatal depression and anxiety in high-risk pregnancies, compare the prevalence of antenatal depression in high-risk pregnancies vs. pregnancies of unspecified obstetric risk and examine the Edinburgh Postnatal Depression Scale (EPDS) and State Trait Anxiety Inventory (STAI) as screening tools for these disorders. METHOD Two hundred high-risk pregnant inpatients at a national public maternity hospital were included. Three psychometric assessment tools were used to evaluate all participants: the diagnostic Mini International Neuropsychiatric Interview and the screening EPDS and STAI. RESULTS Rates of major depression, minor depression, anxiety disorder (agoraphobia, generalized anxiety disorder, panic disorder), and comorbid depression and anxiety were 11%, 7%, 12.5% and 5%, respectively. Major depression was more prevalent in high-risk pregnancies than in the historical cohort of unspecified obstetric risk (11% versus 4.3%). EPDS (cutoff 8/9) screens well for depression and anxiety in high-risk pregnancies (area under the receiver operating characteristic curve=0.82-0.87). CONCLUSION Antenatal depression and anxiety are highly prevalent in a sample of high-risk pregnant Singaporean women. EPDS performs well in screening for depression and anxiety in high-risk pregnant women, with further psychiatric assessment recommended for women with score ≥ 9.

Postoperative steroid therapy for biliary atresia: Systematic review and meta-analysis

BACKGROUND/OBJECTIVES Adjuvant steroid therapy has become popular in the postoperative management of biliary atresia. However, the benefits of steroid therapy are still not clear. We performed a systematic review and meta-analysis to determine the effect of steroids on bile drainage posthepatoportoenterostomy. METHODS Studies published from 1968 to 2014 were searched from MEDLINE, EMBASE, Google scholar and Cochrane databases. A meta-analysis of randomized controlled trials (RCT) and observational studies comparing bile drainage between steroid and nonsteroid therapies posthepatoportoenterostomy was performed. RESULTS Seven studies (2 RCTs and 5 observational studies) were included, comprising 259 cases of nonsteroid and 228 cases of steroid therapies. There was no statistical improvement in jaundice clearance in the steroid group [pooled odds ratio (OR)=1.51; 95% confidence interval (CI) 0.95-2.41; P=0.08; I(2)=30%]. Among 7 studies, 4 studies applied similar moderate high-dose steroid regimens (prednisolone 4-5mg/kg/day for 1-2 weeks followed by weeks of tapering dosage). However, these moderate high-dose regimens demonstrated improved jaundice clearance at 6 months posthepatoportoenterostomy (pooled OR=1.59; 95% CI 1.03-2.45; P=0.04; I(2)=0%). A subgroup analysis also showed that the effect of those moderate high-dose steroids was more pronounced in infants operated on by 70 days of age (pooled OR=1.86; 95% CI 1.08-3.22; P=0.03; I(2)=0%). CONCLUSION Moderate high-dose steroid therapy improves jaundice clearance, especially for infants who undergo hepatoportoenterostomy by 70 days of age. However, more RCTs with longer follow-up are necessary to demonstrate the effect of steroids on the long-term outcomes of biliary atresia.

The role of ischemia in necrotizing enterocolitis

AIM The role of ischemia in the pathogenesis of necrotizing enterocolitis (NEC) remains unclear. We used immunohistochemical markers of hypoxia to identify presence/absence of ischemia in NEC and spontaneous intestinal perforation (SIP) with clinical correlation. METHODS Immunohistochemical staining was performed on 24 NEC and 13 SIP intestinal resection specimens using 2 hypoxia markers, hypoxia inducible factor 1α (HIF-1α) and glucose transporter 1 (GLUT1) and inflammatory markers, leukocyte common antigen (LCA) and myeloperoxidase. Ischemic score (0-6) from the sum of the HIF-1α and GLUT1 staining intensity grades was devised (positive ≥3). Inflammation was graded from the sum of LCA and myeloperoxidase grading. Relevant clinical information was obtained from hospital case records. RESULTS Fourteen NEC specimens had positive ischemic score (4.6±1.2). The remaining 10 NEC (ischemic score 0.7±0.8) and all 13 SIP samples (ischemic score 0.5±0.5) were ischemic-negative. The ischemic-positive cases had classic NEC with multiple areas of bowel necrosis; were associated with later onset, enteral feeding and pneumatosis. In contrast, all ischemic-negative NEC were short-segment NEC with perforation. Their clinical profile was similar to the SIP cases with younger gestational age at birth, early onset, association with ibuprofen/indomethacin usage but not with feeding and pneumatosis. Ischemic scores are correlated with inflammation scores in mucosa but not submucosa. CONCLUSIONS Ischemia as assessed with immunohistochemical markers HIF-1α and GLUT1, has a primary role in pathogenesis of classic NEC only, not in SIP or short-segment NEC with perforation. Better categorization of the different types of NEC can direct appropriate prevention and treatment strategies.

Prognostic Factors Relating to the Outcome of Endodontic Microsurgery

INTRODUCTION The aim of this retrospective study was to evaluate the outcome of endodontic microsurgery and to examine prognostic factors related to healing. METHODS The clinical records of all patients who had undergone endodontic microsurgery from 1997-2003 at the National Dental Centre of Singapore were examined. Teeth with a recall period of 1-2 years were selected. All surgical procedures, except for flap raising and suturing, were performed under a surgical operating microscope. Root-end cavities prepared with ultrasonic tips were filled with Intermediate Restorative Material (Caulk, Milford, DE) or mineral trioxide aggregate. Teeth were evaluated for clinical signs and symptoms after surgery. Preoperative and postoperative radiographs were evaluated independently by 2 endodontists. RESULTS Of 243 root-end surgeries performed, 93 were eligible for the study. Outcomes were categorized as healed, healing, or persistent disease; 78.5% of teeth were assessed to be healed or healing, and 21.5% had persistent disease. The percentages of healed and healing teeth for anterior and posterior root-end surgeries were 76.5% and 80.4%, respectively, with no significant difference in the procedures (P = .8). Ordinal logistic regression showed a higher likelihood of healing in females compared with males (P = .001) and maxillary anterior teeth compared with mandibular anterior teeth (P = .03). Preoperative probing depths of ≤3 mm were significantly associated with healing (P = .05). CONCLUSIONS The use of modern endodontic surgical techniques resulted in 78.5% healed and healing teeth with a recall period of 1-2 years. Prognostic factors affecting successful healing include sex, tooth type, and preoperative probing depths.

Sleep duration and growth outcomes across the first two years of life in the GUSTO study

BACKGROUND AND AIM Short sleep duration is thought to be a factor contributing to increased body mass index (BMI) in both school-age children and adults. Our aim was to determine whether sleep duration associates with growth outcomes during the first two years of life. STUDY DESIGN Participants included 899 children enrolled in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort study. Anthropometric data (weight and body length) and parental reports of sleep duration were collected at 3, 6, 9, 12, 18, and 24 months of age. A mixed-model analysis was used to evaluate the longitudinal association of BMI and body length with sleep duration. In subgroup analyses, effects of ethnicity (Chinese, Indian, and Malay) and short sleep at three months of age (≤12 h per day) were examined on subsequent growth measures. RESULTS In the overall cohort, sleep duration was significantly associated with body length (β = 0.028, 95% confidence interval [CI] 0.002-0.053, p = 0.033), but not BMI, after adjustment for potential confounding factors. Only in Malay children, shorter sleep was associated with a higher BMI (β = -0.042, 95% CI -0.071 to -0.012, p = 0.005) and shorter body length (β = 0.079, 95% CI 0.030-0.128, p = 0.002). In addition, shorter sleep was associated with a higher BMI and shorter body length in children who slept ≤12 h per day at three months of age. CONCLUSION The association between sleep duration and growth outcomes begins in infancy. The small but significant relationship between sleep and growth anthropometric measures in early life might be amplified in later childhood.

Impact of an Antimicrobial Stewardship Program on the Use of Carbapenems in a Tertiary Women's and Children's Hospital, Singapore

Antimicrobial stewardship programs (ASPs) promote the judicious use of antimicrobials by limiting inappropriate use. This article evaluates the impact of a prospective‐audit‐and‐feedback ASP implementation on the appropriate utilization of carbapenems in a tertiary pediatrics and obstetrics/gynecology hospital in Singapore (KKH) after the establishment of an ASP in July 2011.

A Retrospective Study of Temporomandibular Joint Internal Derangement Treated with Arthrocentesis and Arthroscopy

Introduction: Internal Derangement of the Temporomandibular Joint is an intra-articular condition in which there is a disruption in the normal relationship of the articular disc to the articular eminence and the condyle when the joint is at rest or in function. Patients may complain of pain and/or limitation of mouth opening. Treatment of internal derangement of temporomandibular joint includes arthrocentesis and arthroscopy. The aims of this retrospective study are to examine the efficacy of arthrocentesis and arthroscopy in the treatment of internal derangement of temporomandibular joint, specifically in relation to joint movement and pain. Methods: Twenty consecutive patients with internal derangement of temporomandibular joint seen in National Dental Centre of Singapore, from 2010 to 2011, were included in this study. Nine patients underwent arthrocentesis and 11 had arthroscopic lysis and lavage. The pre and postoperative pain score, in Visual Analogue Scale (0 to 10) and maximal inter-incisal opening were recorded to evaluate the effectiveness of both treatment modalities. The patients were reviewed one week and one month post-operation. The data obtained were statistically analysed. Results: Significant increase in postoperative mouth opening and reduction in pain were found in both groups of patients. In the arthrocentesis group, the mean increase in maximal inter-incisal opening was 13 ± 5mm and reduction of pain in VAS was 4.56 ± 1.74. For the arthroscopy group, the mean increase in maximal inter-incisal opening was 6.6mm ± 4.8mm and the reduction of pain was 2.5 ± 2.2. Duration of symptoms prior to treatment appeared to have influenced the treatment outcome of both treatments. Conclusion: Arthrocentesis and arthroscopy are effective in the treatment of internal derangement of temporomandibular joint. Factors that may influence treatment outcomes need to be investigated to provide more information on the predictability of arthrocentesis and arthroscopy.

Segmental mandibular bone reconstruction with a carbonate-substituted hydroxyapatite-coated modular endoprosthetic poly(ɛ-caprolactone) scaffold in Macaca fascicularis

A bio-degradable scaffold incorporating osteoinductive factors is one of the alternative methods for achieving the regeneration of a mandibular bone defect. The current pilot study addressed such a bone reconstruction in a non-human primate model, Macaca fascicularis monkeys, with an engineered poly(ɛ-caprolactone) (PCL) scaffold, provided with a carbonate-substituted hydroxyapatite coating. The scaffolds were implanted into unilaterally created mandibular segmental defects in 24 monkeys. Three experimental groups were formed: (1) scaffolds with rhBMP-2 (n = 8), (2) scaffolds with autologous mixed bone marrow cells (n = 8), and (3) empty scaffolds as a control group (n = 8). Evaluation was based on clinical observation as well as micro-CT, mechanical, and histological analyses. Despite a high infection rate, the overall results showed that the currently designed PCL scaffolds had insufficient load-bearing capability, and complete bone union was not achieved after 6 months of implantation. Nevertheless, the group of PCL scaffolds loaded with rhBMP-2 showed evidence of bone-regenerative potential, in contrast to PCL with autologous mixed bone marrow cells and the control group.

Patient Oriented Research: The Duke-NUS Medical Student Experience

The next generation of doctors will practice medicine in an era of evidence-based medicine, attended by an exponential increase in basic, translational, clinical and health-service-related research. By the start of their residency, today’s medical school graduates must have the ability to understand and apply medical research literature to patient care. Knowledge of the advances in clinical research designs, methods and analytic approaches will empower them to critically evaluate research publications and set a good foundation for participation in research throughout their careers.