Biomedical subjects

L Y Ho

Publications and source records attributed to L Y Ho.

At least 19 recordsLinked to original sources

PubMed2005

Incidence, risk factors of retinopathy of prematurity among very low birth weight infants in Singapore.

INTRODUCTION: To determine the incidence, risk factors and need for surgery for retinopathy of prematurity (ROP) among very-low-birth-weight (VLBW) infants. MATERIALS AND METHODS: This was a retrospective study of all VLBW infants managed by the department over 14 years, from 1988 to 2001. Preterm infants were examined according to the Royal College of Ophthalmologists' guidelines, and retinopathy was graded following the International Classification of ROP. All VLBW infants examined for ROP were included and data were retrieved retrospectively and analysed for maternal, medical, obstetric and neonatal risk factors using logistic regression. RESULTS: Of the 564 VLBW infants who fit the screening criteria, ROP was detected in 165 (29.2%) of VLBW infants; of whom 49% of infants had stage 1 disease, 24% were at stage 2, and 27% were at stage 3 or more. Among 45 infants with stage 3 disease or more, treatment was needed in 62.2% (28/45). No ROP was detected in infants greater than 33 weeks of gestation. Only 0.6 % (1/164) of infants greater than 30 weeks of gestational age (GA) needed surgery for ROP. Using birth weight (BW) criteria, stage 3 ROP was noted only in 1% (6/564) of infants with BW >1000 g. Of all ROP requiring surgery, 89% (25/28) of infants were <1000 g as compared to 11% (3/28) who were >1000 g infants. The median age of onset of ROP was 35 weeks (range, 31 to 41) corrected age. By univariate analysis for threshold ROP, preeclampsia, prenatal betamethasone exposure, gestational age, birth weight, 1-minute Apgar score, hyaline membrane disease (HMD), surfactant usage, hypotension, septicaemia, intraventricular haemorrhage duration of supplemental oxygen, ventilation and chronic lung disease were associated with ROP requiring surgery (i.e., threshold ROP, P <0.05). However, using multiple logistic regression analyses for ROP, maternal preeclampsia [odds ratio (OR), 2.52; confidence interval (CI), 1.32 to 4.7], birth weight (OR, 0.99; CI, 0.996 to 0.999), pulmonary haemorrhage (OR, 4.61; CI, 1.04 to 20.4), duration of ventilation (OR, 1.06; CI, 1.04 to 1.08) and duration of continuous positive airway pressure (CPAP) (OR, 1.02; CI, 1.01 to 1.04) were factors predictive of development of threshold ROP. CONCLUSION: The incidence of ROP among VLBW infants was 29.2%. ROP was strongly associated with smaller, more immature and sicker infants. The median age of onset of ROP was 35 weeks (range, 31 to 40 weeks) postmenstrual age. Infants <30 weeks of GA and/or infant with BW <1000 g are at considerable risk for threshold ROP. The main risk factors for development of threshold ROP by regression analysis are maternal preeclampsia, birth weight, and presence of pulmonary haemorrhage, duration of ventilation and continuous positive pressure ventilation. We suggest that both immaturity and compromised pulmonary function are both important aetiological factors in the development of ROP. Prevention of prematurity, control of preeclampsia, judicious use of ventilation and oxygen therapy are the only promising factors that may reduce the incidence and severity of ROP in this high-risk infant.

Gestational Age↗

PubMed2005

Universal newborn hearing screening in Singapore: the need, implementation and challenges.

With about 1 in 1000 born with severe to profound hearing loss and about 5 in 1000 with lesser degrees of loss, congenital deafness is the commonest major birth defect. It is the recommended standard that hearing loss in newborns be detected by 3 months of age and intervention implemented by 6 months of age. Delayed detection and intervention may affect speech, language and psychosocial development, resulting in poor academic achievements. Universal newborn hearing screening (UNHS) is the only effective way of detecting all babies with hearing loss, within the recommended time frame. A survey in Singapore revealed that traditional childhood hearing screening programmes resulted in late detection (mean age, 20.8 months; range, 0 to 86 months) and late intervention (mean age, 42.4 months; range, 1 to 120 months). Increasingly, UNHS is becoming standard medical care in developed countries. In Singapore, UNHS has been implemented in all hospitals with obstetric services. Although a screening rate of more than 99% has been achieved in public hospitals, private hospitals have a screening rate of only about 77%. Parents' awareness and acceptance of early detection is still lacking, and this needs to be addressed by appropriate public education. Support from obstetricians and paediatricians will significantly contribute towards this objective. Effective programme management is essential; this includes the use of data management systems, the maintenance of a team of experienced screeners, and efficient coordination between screening and diagnostic services. Early detection of childhood deafness, together with early and effective intervention, maximises the chances of successful integration into mainstream education and society.

Audiometry, Evoked Response↗

PubMed2003

The origin of the triploid in Paragonimus westermani on the basis of variable regions in the mitochondrial DNA.

Triploid, parthenogenetic forms of the lungfluke, Paragonimus westermani, occur in Japan, Korea and China. The origin(s) of triploidy has been debated over the years. Sequences of two regions in the mitochondrial DNA, i.e. partial lrRNA (16S), and a portion of the non-coding region, were obtained from natural populations of P. westermani. All triploid individuals (Japan, Korea, China) and a single tetraploid individual (China) had identical sequences in the 16S region studied. Some sequence variation was observed among diploids, with those from Taiwan being distinct from the remainder. Both neighbour joining and parsimony trees using the 16S region placed diploid individuals from southwestern Japan close to the triploids and the tetraploid. The fragment amplified from the mitochondrial non-coding region showed dimorphism. One form (type A) consisted of 239 bp comprising two identical tracts of 70 bp separated by a tract of 93 bp. The second form (Type B) consisted of only a single 70 bp tract. All diploid individuals from Taiwan, China and Korea possessed type A, while those from Japan were polymorphic; individuals from Oita and Hyogo had type B, those from Chiba had type A, but both types were found in Mie. On the other hand, all of the triploid individuals and two tetraploid individuals possessed type B. Both the form present in the non-coding region and the 16S sequence suggest an affinity between a south-eastern group of diploid populations in Japan and the triploid form. A possible mechanism responsible for the origin of the triploid is discussed.

Animals↗

PubMed2003

Perinatal care at the threshold of viability--from principles to practice.

The threatened birth of an extremely-low-birth-weight (ELBW) and gestational age infant presents complex medical, social and ethical issues for the family and the health professionals. Improved survival may be accompanied by increased risks of chronic medical problems and neurodevelopmental disabilities. It is difficult to define "how small is too small" and to decide "how much is too much" in providing optimal management of the mother and infant when delivery takes place at the threshold of viability. An individualised prognostic strategy appears to be the most appropriate approach. Through a process of communication and value exploration between the well-meaning parents and well-intentioned physicians, the goal is to reach a consensual decision that respects parental authority and promotes physician beneficence, with the best interests of the infant placed in the centre of the analysis.

Decision Making↗

PubMed2003

General practitioners' knowledge on childhood developmental and behavioural disorders.

INTRODUCTION: Childhood developmental and behavioural disorders are increasingly being recognised, with high demands for earlier diagnosis and intervention. In Singapore, referrals to the Child Development Unit, KK Women's and Children's Hospital, originate mainly from primary health care practitioners, who therefore should have adequate baseline knowledge of normal development as well as common developmental and behavioural disorders. METHODOLOGY: A pilot study, using a questionnaire survey, was conducted, with the aim of assessing existing knowledge in childhood developmental and behavioural paediatrics amongst a cohort of general practitioners (GPs) in Singapore. True/False questions on normal development as well as developmental disorders such as autistic spectrum disorder (ASD), attention deficit/hyperactivity disorder (ADHD) and learning disability, were structured. These disorders were selected because of their relatively higher prevalence. RESULTS: A total of 48 GPs were surveyed, representing 2% of non-specialists practising in the private sector. The median total score (T-score) was 9 (range 6 to 13) of a possible 14. Only just over a-third of the group achieved the pass rate (defined arbitrarily as 75%) for T-score, with two-thirds replying correctly to all questions on normal development. Scores for factual ASD/ADHD questions were also not ideal, with some myths being believed as truths. CONCLUSION: The scores reflect knowledge and educational deficits in developmental paediatric medicine amongst the study cohort. Expected to provide holistic care and counselling, these GPs are currently insufficiently equipped with the necessary knowledge and skills to support families of special-needs children. Education and training programmes in this aspect of paediatric medicine are clearly needed, through the organisation of CME lectures and incorporation of various developmental topics into the training curriculum. This will enable early identification and diagnosis of childhood developmental and behavioural disorders, which will in turn allow greater optimisation of potential and functionality in these special-needs children.

Adult↗

PubMed2002

Bronchopulmonary dysplasia and chronic lung disease of infancy: strategies for prevention and management.

Remarkable advances in the treatment of neonatal respiratory disorders, such as antenatal glucocorticoid therapy, surfactant replacement therapy and alternative modes of ventilation, have reduced neonatal mortality and acute respiratory morbidity. However, bronchopulmonary dysplasia and chronic lung disease of infancy remain a substantial complication, especially among the most immature infants. The pathogenesis of chronic lung disease is complex and multifactorial. Prevention and treatment will require a comprehensive multiprong approach with specific interventions and practices focused on different levels of the pathways leading to chronic lung changes. Future improvements in care will require a better understanding of lung development and lung repair mechanisms. However, the ultimate and most effective approach should be a relentless pursuit for measures to prevent premature births.

Bronchopulmonary Dysplasia↗

PubMed2002

Two-year outcome of normal-birth-weight infants admitted to a Singapore neonatal intensive care unit.

INTRODUCTION: To describe the characteristics, the immediate and short-term outcome and predictors of mortality in normal-birth-weight (NBW) infants admitted to a tertiary neonatal intensive care unit (NICU) in Singapore. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 137 consecutive NBW infants admitted to the NICU of the Singapore General Hospital from January 1991 to December 1992. Data on the diagnoses, clinical presentation of illness, intervention received, complications and outcome as well as follow-up patterns for the first 2 years of life, were collected and analysed. RESULTS: NBW NICU infants comprised 1.8% of births in our hospital and 40.8% of all NICU admissions. The main reasons for NICU admissions were respiratory disorders (61.3%), congenital anomalies (15.3%) and asphyxia neonatorum (11.7%). Respiratory support was necessary in 81.8%. Among those ventilated, the only predictive factor contributing to mortality was the mean inspired oxygen concentration. The mortality rate was 11.7%. Causes of death included congenital anomalies (43.75%), asphyxia neonatorum (31.25%) and pulmonary failure secondary to meconium aspiration syndrome (12.5%). The median hospital stay among survivors (88.3%) was 11.0 (range, 4 to 70) days. Of 42 patients (out of 117 survivors) who received follow-up for at least 6 months, 39 infants did not have evidence of any major neurodevelopmental abnormalities at their last follow-up visit, prior to or at 2 years of age. CONCLUSIONS: Despite their short hospital stay (compared to very-low-birth-weight infants), the high volume of NBW admissions make the care of this population an important area for review to enhance advances in and hence, reduce the cost of NICU care. With improved antenatal diagnostic techniques (allowing earlier and more accurate diagnosis of congenital malformations) and better antenatal and perinatal care (allowing better management of at-risk pregnancies), it is anticipated that there should be a reduction in such admissions with better outcomes. Close follow-up of this high-risk group of infants is also important in order to offer early intervention to those who may possibly have perinatally-related developmental difficulties.

Birth Weight↗

PubMed2001

Effect of recombinant human erythropoietin on transfusion needs in preterm infants.

OBJECTIVE: To study the efficacy, safety and cost effectiveness of recombinant human erythropoietin (r-HuEPO) in reducing erythrocyte transfusion needs in very low birthweight (VLBW) infants. METHODS: We conducted a non-blind randomized controlled trial and assigned 100 VLBW infants, less than 33 weeks gestation, to receive either r-HuEPO 750 U/kg per week subcutaneously from day 5 to day 40 or no erythropoietin (EPO). Infants received oral iron 3-6 mg/kg per day from day 10. Transfusion needs were analysed for all enrolled infants and in five weight subgroups: birthweight of less than 600 g, 600-799 g, 800-999 g, 1000-1199 g and infants more than 1200 g. RESULTS: VLBW infants on r-HuEPO attained higher reticulocyte counts and haematocrit than control infants but the mean number of transfusions and volume of erythrocyte transfused per infant were not statistically different. Of infants 800-999 g at birth, the mean number of transfusions per infant was 2.1 compared with 3.5 transfusions per control infant (P = 0.04). Volume of erythrocytes transfused was 34.9 +/- 32.1 mL/kg in r-HuEPO-treated infants and 56.6 +/- 25.8 mL/kg in control infants (P = 0.03). The cost per patient for transfusion and EPO was S$388 for r-HuEPO recipient and S$438 for control infant. Blood pressure, neutrophil count, platelet count and complications of prematurity were not significantly different in both groups of VLBW infants. CONCLUSION: r-HuEPO at 750 U/kg per week stimulates erythropoiesis in VLBW infants but significantly reduces the need for erythrocyte transfusion only in infants weighing 800-999 g at birth.

Blood Transfusion↗

PubMed2000

Molecular phylogeographic studies on Paragonimus westermani in Asia.

The lung fluke, Paragonimus westermani (Kerbert, 1878), is widely distributed in Asia, and exhibits much variation in its biological properties. Previous phylogenetic studies using DNA sequences have demonstrated that samples from north-east Asia form a tight group distinct from samples from south Asia (Philippines, Thailand, Malaysia). Among countries from the latter region, considerable molecular diversity was observed. This was investigated further using additional DNA sequences (partial mitochondrial cytochrome c oxidase subunit 1 (COI) and the second internal transcribed spacer of the nuclear ribosomal gene repeat (ITS2)) from additional samples of P. westermani. Phylogenies inferred from these again found three or four groups within P. westermani, depending on the method of analysis. Populations of P. westermani from north-east Asia use snail hosts of the family Pleuroceridae and differ in other biological properties from populations in south Asia (that use snail hosts of the family Thiaridae). It is considered that the populations we sampled can be divided into two species, one in north-east Asia and the other in south Asia.

Animals↗

PubMed2000

Penile length of newborns in Singapore.

Micropenis is an important sign in congenital hypopituitarism and various disorders. Documented norms for penile length exist only for babies of Caucasian and Middle-Eastern origin. This study was carried out to establish such norms for Asian newborns. We studied 228 male live births within their first three days of life. Stretched penile lengths were marked off on unmarked wooden spatulas, which were placed vertically along the dorsal aspect of the penis, with one rounded end on the pubic bone. The mean penile length +/- S.D. for the full-term Asian baby was 3.6 +/- 0.4 cm. Race had a significant effect: Chinese 3.5 cm, Malay 3.6 cm and Indian 3.8 cm. Penile length correlated with birth weight and gestational age. Asian babies thus have similar norms to Caucasian babies. An Asian newborn whose penis measures less than 2.6 cm has micropenis and may need prompt investigation for underlying endocrine disorders.

Birth Weight↗

PubMed1999

Newborn screening in Singapore.

Neonatal screening in Singapore for G6PD deficiency started in 1965. Screening for congenital hypothyroidism started in 1981 as a pilot research program and by 1990, it became nationwide. Screening for congenital hypothyroidism is by the measurement of TSH in the cord serum with recall of those exceeding the 99th percentile, by about 3-4 days of life. Treatment is usually started within a week of life. Over 400,000 newborns have been screened and the screening rate has been about 99.95%. The incidence rate is about 1 in 3,000. G6PD activity in the cord blood is measured using semi-quantitative rapid screening tests. Those identified are physically protected from environmental triggers by keeping them in hospital for a variable period of time. Parents are counseled. Data obtained from 22,830 newborns from the National University Hospital revealed incidence rates of 1.62% in all newborns, 3.15% in males and 0.11% in females. The Chinese and Malay males had a higher (3.94% and 2.95%) incidence respectively when compared to the Indian males with (0.66% incidence). The application of the preventive measures has resulted in no report of kernicterus in the last 20 years. Our efforts are now focused on minimizing the recall rate in the case of hypothyroidism screening, reducing the period of stay in hospital in those with G6PD deficiency and considering the introduction of a PKU screening program in Singapore.

Congenital Hypothyroidism↗

PubMed1999

Mass newborn screening for glucose-6-phosphate dehydrogenase deficiency in Singapore.

Recognition of kernicterus as a significant contributor to newborn mortality and morbidity in G6PD deficient babies and the ease with which G6PD deficiency could be detected and kernicterus prevented by avoidance of triggers, led to the establishment of mass newborn screening for G6PD deficiency in 1965. G6PD deficient newborns are identified within a day of birth by measuring the enzyme activity in cord blood. They are then physically protected from triggers by keeping them in the hospital for the first 2 weeks of life after their parents are counseled. Enzyme activity is measured using Wong's in-house modification of the Bernstein's technique or the BM G6PD Deficiency Screening test based on the Beutler assay. Close to 1.6 million newborns, representing practically 100% of all births have been screened. Analysis of data from 22,830 newborns at the National University Hospital reveals an incidence of 1.62% in all newborns. 3.15% in males and and 0.11% in females. A distinct racial variation in the incidence of deficiency was observed in males: Chinese 3.94%, Malays 2.95% and Indians 0.66%. Intermediate deficiency was most frequently identified (1.83%) in Chinese females. With the preventive measures. the incidence of kernicterus has dropped dramatically and there has been, over the last 20 years, no reported cases of kernicterus in newborns with G6PD deficiency. We are now looking at issues like comparing different assay techniques and determining a shorter period of stay in hospital. We believe that all Asians, especially Chinese babies, should be screened for G6PD deficiency, irrespective of which country the child is born.

Female↗

PubMed1998

Congenital sodium diarrhoea in an Indian girl.

We report the case of a newborn Indian girl with congenital sodium diarrhoea (CSD) who presented typically in utero, in whom diagnosis was made from markedly raised stool sodium in the presence of an alkaline stool. Treatment with sodium citrate normalised her metabolic and electrolyte status but resulted in transient uremia necessitating supplementation with sodium bicarbonate instead. She died at 11 weeks old following re-admission in a moribund state with grossly increased abdominal distension. Her fatal outcome in infancy suggests that CSD has a wide spectrum of clinical severity.

Citrates↗

PubMed1997

Mortality among infants with high-risk congenital diaphragmatic hernia in Singapore.

Several factors suggested to predict mortality in congenital diaphragmatic hernia (CDH) have not always been applicable in different centers. A retrospective review was conducted of 19 consecutive neonates in Singapore in whom CDH was diagnosed within 12 hours of birth to identify factors associated with mortality. Of the 19 cases, 15 (79%) were diagnosed using antenatal ultrasonography. Eight (42%) underwent primary repair at a median age of 23 hours (range, 12 to 50 hours). Of the 19 infants, 15 died (mortality rate, 79%). Survivors until hospital discharge were compared with nonsurvivors. Antenatal diagnosis and stomach position in left-sided defects had no effect on outcome, although polyhydramnios tended to be associated with nonsurvival. Significant postnatal factors associated with mortality included a low arterial pH level, low initial arterial-alveolar oxygen ratio, high initial alveolar-arterial oxygen gradient, as well as high oxygenation and ventilation indices. These results reflect difficulty in oxygenation because of pulmonary hypoplasia despite evidence of adequate ventilation. There was no difference between survivors and nonsurvivors in either their initial or best postductal blood gases. The "Bohn quadrants" did not aid in predicting survival of infants who underwent repair because all eight such infants had best postductal carbon dioxide values of less than 40 mm Hg and ventilation indices of less than 1,000. Yet only four (50%) survived until hospital discharge. Large-scale evaluation of these factors may be required in the future to demonstrate their validity and reliability because of changing management strategies for CDH.

Carbon Dioxide↗

PubMed1997

Chronic lung disease in very low birthweight infants: a 5-year review.

OBJECTIVES: To determine the incidence, clinical spectrum and outcome of very low birthweight (VLBW) infants with chronic lung disease (CLD), and evaluate associated factors. METHODOLOGY: Retrospective review of 265 VLBW infants managed in the NICU from January 1988 to December 1992. RESULTS: The overall neonatal survival rate for VLBW infants was 83%. Sixty-five (25%) infants had CLD, of whom 42% had severe CLD. Mortality in infants with CLD was 11%. In contrast with infants without CLD, CLD infants had significantly higher risk of adverse neurodevelopment with cerebral palsy documented in 13.5% and functional disability recorded in 34.6% at 2 years corrected age. Factors associated with the development of CLD included; decreasing birthweight (OR 0.98, CI 0.97-0.99), septicaemia (OR 4.96, CI 1.57-15.65), necrotizing enterocolitis (OR 119.07, CI 4.98-2845.04), hyaline membrane disease (OR 5.34, CI 1.83-15.55), patent ductus arteriosus (OR 4.46, CI 1.75-11.36) and increasing fraction of inspired oxygen concentration in the first week of life (OR 1.09, CI 1.04-1.14). CONCLUSIONS: Chronic lung disease occurs frequently in VLBW infants and is associated with a high incidence of adverse neurodevelopment. Further studies to clarify the role of non-respiratory factors such as patent ductus arteriosus (PDA) and sepsis in the pathogenesis of CLD may reduce the incidence or prevent the development of CLD in these preterm infants.

Cerebral Palsy↗

PubMed1997

A 3-year review of meconium aspiration syndrome.

AIM OF STUDY: To review the incidence, morbidity and mortality of Meconium Aspiration Syndrome (MAS). To identify possible predictors of MAS in newborns with thick meconium-stained amniotic fluid (MSAF) at delivery. METHODOLOGY: Case records of babies with MSAF delivered in Singapore General Hospital from 1.1.1991 to 31.12.1993 were studied retrospectively. RESULTS: In the study period, 1,893 babies (15% of live births) had MSAF and 174 babies (1.4% live births) developed MAS. The incidences of MAS in newborns with light, moderate and thick MSAF were 0.3%, 5.8% and 61% respectively. Complications associated with MAS were metabolic acidosis (52%), air leak syndrome (2%), persistent pulmonary hypertension (2%) and hypoxic ischaemic encephalopathy (0.5%). The mortality rate of babies with MAS was 2%. Newborns with thick MSAF were more likely to develop MAS if they were males, small-for- gestational-age, had fetal distress and meconium was sucked from the trachea at birth. CONCLUSION: Vigilant perinatal monitoring of high risk babies with MSAF and proper resuscitation at birth would help reduce the incidence of MAS and its associated complications.

Female↗

PubMed1997

Partial monosomy for chromosome 22 in a girl with mental retardation.

This report describes a 5-year 6-month-old Chinese girl with partial monosomy for the long arm of chromosome 22. The karyotype was 46,XX/46,XX,del (22) (q13.2). She presented with global developmental delay. Clinical features include seizures, failure-to-thrive, prominent ears, long philtrum and abnormal skin pigmentation on the face and limbs.

Child, Preschool↗

PubMed1997

Williams syndrome--the Singapore General Hospital experience.

Williams syndrome first described in 1961 is generally characterised by mental deficiency, gregarious personality, unusual "elfin" facies, supravalvular aortic stenosis and idiopathic infantile hypercalcaemia. Patients with Williams syndrome show a hemizygous submicroscopic deletion of 7q11.23 detectable by fluorescent in-situ hybridisation (FISH). The deleted portion of the chromosome corresponds to the Elastin gene. We report 3 girls with characteristics of Williams syndrome in whom the diagnosis was confirmed by demonstration of the hemizygous deletion of 7q11.23 in the karyotype by FISH. These patients, aged 6, 7 and 10 years, showed the characteristic facies and gregarious personalities. Some developmental delay with mild mental deficiency and dysmorphic facies were prominent features in the initial presentation. Cardiac lesions found in these patients were small patent ductus arteriosus which closed, pulmonary valvular stenosis and mitral valve prolapse associated with mitral regurgitation respectively. Hypercalcaemia was not documented in these patients. Learning difficulty was a major issue and all patients required special schooling. Chromosome analyses done on peripheral blood were found to be normal in all patients. FISH using the Elastin Williams Syndrome Chromosome Region (WSCR) probes (oncor) showed the hemizygous deletion of 7q11.23. Diagnosis of Williams syndrome can now be confidently confirmed with the help of FISH.

Child↗