From the 20th to the 21st century: the first 100 years of paediatrics in Singapore

In Singapore, paediatrics as a separate discipline was started in 1921 at Singapore General Hospital (SGH). From Mistri Wing to Alexandra Hospital (AH) and Tan Tock Seng Hospital (TTSH), paediatrics was started at National University Hospital (NUH) and the Children’s Hospital at KK Women’s and Children’s Hospital (KKH) from 1997. After World War II, neonatology started in KKH, followed by Toa Payoh Hospital (TPH), AH, NUH and SGH. Neonates from TPH and AH were moved to KKH in 1990. Our pioneering giants include Dr Gopal Haridas, Professors Wong Hock Boon (First Paediatrics Professor), Tan Cheng Lim and Tan Kim Leong. Paediatrics in Singapore is resplendent with many achievements. Prof Wong identified the relationship of hyperbilirubinaemia/kernicterus with glucose-6-phosphate dehydrogenase (G6PD) deficiency and initiated G6PD deficiency screening. This has saved many lives and improved the overall health of children in Singapore. 100 years on, we stand firmly on the shoulders of our pioneering clinician giants as we face the paediatric millennial health needs of this new century.

Liver transplantation in children: the Singapore experience

Paediatric liver transplantation has come a long way since its acceptance as a treatment option for children with end-stage liver disease. From 1990 to 2020, a total of 434 liver transplants were performed in National University Hospital, Singapore, out of which 143 were performed in children. The majority of the liver grafts were from living donors, mainly the parents. Our long-term survival rates are comparable to those of major transplant centres worldwide. These patients usually have a productive and good quality of life.

Rates and determinants of antibiotics and probiotics prescription to children in Asia-Pacific countries

Antibiotic therapy may have important side effects. Guidelines recommend the administration of specific probiotics to reduce the risk of antibiotic-associated diarrhoea (AAD). The rates and determinants of antibiotics and co-prescription of probiotics in children remain poorly known in Asia-Pacific countries, which are very heterogenous in terms of economic development, health care organization and health policies. A survey among general practitioners (GPs) and paediatricians was performed in seven countries of the Asia-Pacific area (Australia, Japan, Indonesia, India, China, Singapore, and South Korea). Physicians completed an online questionnaire that explored their current habits and the determinants for prescribing antibiotics and probiotics. For the 731 physicians who completed the questionnaire (390 paediatricians and 341 GPs), 37% of all consultations for a child led to the prescription of antibiotics (ranging from 17% in Australia to 47% in India). A large majority of physicians (84%) agreed that antibiotics disrupted gut microbiota and considered probiotics an effective intervention to prevent AAD (68%). However, only 33% co-prescribed probiotics with antibiotics (ranging from 13% in Japan to 60% in South Korea). The main reasons for prescribing probiotics were previous episodes of AAD (61%), presence of diarrhoea (55%), prolonged antibiotic treatment (54%) or amoxicillin-clavulanic acid therapy (54%). Although current local guidelines recommend the use of selected probiotics in children receiving antibiotics in Asia-Pacific area, the rates of antibiotics and probiotics prescription significantly vary among countries and are deeply affected by country-related cultural and organisational issues.

Bocavirus infection following paediatric liver transplantation

HBoV is an emergent virus, which is frequently detected as a co-infective agent. However, it can cause disease on its own. It is associated with respiratory and diarrhoeal illness in children and adults, whether immunocompetent or immunocompromised. We report HBoV infection in a child post-liver transplantation, who presented with persistent fever and mild tachypnea, 3 weeks after a successful transplant. She recovered spontaneously with no graft dysfunction.

Two consecutive partial liver transplants in a patient with Classic Maple Syrup Urine Disease

Maple syrup urine disease is caused by a deficiency in the branched chain ketoacid dehydrogenase (BCKAD) complex. This results in the accumulation of branched chain amino acids (BCAA) and branched chain ketoacids in the body. Even when aggressively treated with dietary restriction of BCAA, patients experience long term cognitive, neurological and psychosocial problems. Liver transplantation from deceased donors has been shown to be an effective modality in introducing adequate BCKAD activity, attaining a metabolic cure for patients. Here, we report the clinical course of the first known patient with classic MSUD who received two consecutive partial liver grafts from two different living non-carrier donors and his five year outcome posttransplant. We also show that despite the failure of the first liver graft, and initial acute cellular rejection of the second liver graft in our patient, his metabolic control remained good without metabolic decompensation.

Unusual shunt for symptomatic portal vein thrombosis after liver transplantation - Clatworthy revisited

PV thrombosis is not an uncommon occurrence following pediatric LT. Symptomatic PHT following PV thrombosis is treated medically, surgical portosystemic shunting (mesorex, splenorenal, and mesocaval) being reserved for refractory cases. A 10-yr-old boy suffered recurrent malena and hemorrhagic shock because of chronic PV thrombosis following LT nine yr ago (1999). Extensive work-up failed to localize the bleeding source. The liver function remained normal. Initial attempts at surgical shunts failed owing to thrombosis (mesocaval 2001, splenorenal, inferior mesenteric-left renal vein, splenic-left external iliac vein 2008). In this situation, we performed a Clatworthy shunt by anastomosing the divided lower end of the LCIV to the side of SMV. There was a single, large caliber anastomosis. Post-operatively, the malena stopped completely, and clinically, there was no lower limb edema or encephalopathy. Doppler USG revealed persistence of hepatopetal flow within the portal collaterals. Follow-up at two yr reveals stable hepatic function with a patent shunt. To the best of our knowledge, we are not aware of a Clatworthy shunt being performed in a transplant setting. We reviewed the literature pertaining to this shunt in non-transplant patients with PHT.

Identification of immunodominant VP1 linear epitope of enterovirus 71 (EV71) using synthetic peptides for detecting human anti-EV71 IgG antibodies in Western blots

A major IgG-specific immunodominant VP1 linear epitope of enterovirus 71 (EV71) strain 41 (5865/SIN/00009), defined by the core sequence LEGTTNPNG, was identified by Pepscan analysis. Oligonucleotides corresponding to the amino-acid sequence of synthetic peptide SP32 were cloned and over-expressed in Escherichia coli as a recombinant glutathione-S-transferase (GST)-SP32 fusion protein. In ELISAs, this protein did not react with human anti-EV71 IgG antibodies, but there was significant immunoreactivity according to western blot analysis. The amino-acid sequence of SP32 was highly specific for detecting EV71 strains in western blot analysis, and showed no immunoreactivity with monoclonal antibodies raised against other enteroviruses, e.g., CA9 and Echo 6.

Referral patterns and waiting times for liver transplantation in Singapore

INTRODUCTION

Referral patterns, waiting times, waiting list, and mortality provide information on how effectively a transplant programme deals with referred patients. This paper aims to review these parameters in the Singapore National Liver Transplant Programme.

METHODS

Data of all patients referred to the Singapore National Liver Transplant Programme since its inception were captured and outcomes were retrieved and described.

RESULTS

562 patients were referred for liver transplant evaluation from 1990-2004, consisting of 457 adults and 105 children. The main indications for referral were hepatitis B liver disease and hepatocellular carcinoma in adults, and biliary atresia in children. Most patients were of United Network of Organ Sharing (UNOS) status 3 or 4 at the time of referral. 114 (20.28 percent) patients had transplants, consisting of 66 adults (14.44 percent) and 48 (45.71 percent) children. 138 adults and ten children were rejected for transplant, mainly for the reason of being "too early". The median waiting time for adults who had transplants was 3.3 months while adults still on the waiting list had been waiting for 16.2 months. The overall waiting list mortality was 44.3 percent, being 52.5 percent in adults and 23.2 percent in children.

CONCLUSION

The overall transplantation rate is low and the waiting list mortality is high as a result of low availability of organs, particularly in adults. Paediatric liver transplant appears to have been better at dealing with referred patients but this is probably due to availability of living-related liver transplant. Improvement in these may result from the Human Organ Transplant Act.

Liver transplantation in Singapore 1990-2004

INTRODUCTION

Liver transplantation is the accepted standard of care for patients with hepatocellular carcinoma, decompensated liver cirrhosis, and acute liver failure. Since the first liver transplant done in Singapore in 1990, results have been improving. We review the overall results of liver transplantation over the last 15 years.

METHODS

All transplant cases from 1990 to 2004 were reviewed retrospectively.

RESULTS

100 liver transplants were performed over the last 15 years; four in the first five years and 96 in the subsequent ten years. Overall one- and five-year survival rates were 80 percent and 78 percent, respectively. 44 were paediatric transplants, of which biliary atresia was the commonest indication for paediatric transplant. 56 were adult transplants of which hepatocellular carcinoma and decompensated hepatitis B cirrhosis were the commonest indications for adult transplant. Infection remained the commonest cause of mortality.

CONCLUSION

The number of transplants carried out per year was small due to the low cadaveric donation rate, but the survival of liver transplant patients was comparable to well-established liver transplant centres.

Outcome of liver transplantation for children with liver disease

INTRODUCTION

The advent of liver transplantation has revolutionised the outcome of children with both acute liver failure and chronic end-stage liver disease. The aim of this study was to review the outcome of all paediatric liver transplants performed since the National Liver Transplant Programme began in 1990.

METHODS

A retrospective review of all paediatric liver transplants from 1990 to December 2004 was performed.

RESULTS

46 liver transplants were performed in 43 children, of whom 23 (53.3 percent) were female. Median age at transplant was 21 months (range 11 months to 14 years). The most common indication for liver transplant was biliary atresia (71.7 percent). Living-related transplants accounted for 63 percent (29). Re-transplant rate was 6.5 percent with allograft loss as a result of hepatic artery thrombosis (two) and hepatic vein thrombosis (one). Tacrolimus was the primary immunosuppressive agent used in 89 percent of patients, with a 19.6 percent incidence of acute allograft rejection within the first six months. There were nine deaths. They were related to portal vein thrombosis (three), chronic rejection (one), sepsis (two), post-transplant lymphoproliferative disease (two) and primary graft non-function (one). Overall actuarial one- and five-year survival rate was 85.7 percent and 81.8 percent, respectively.

CONCLUSION

Liver transplantation is an established form of intervention for end-stage liver disease and a variety of liver-related metabolic disease. Our results are comparable to those of well-established liver transplant centres.

A short report on highlights of worldwide development of RIX4414: A Singaporean experience

In Singapore, we conducted a phase II randomized, double-blind, placebo-controlled dose ranging study using an attenuated human rotavirus vaccine, RIX4414. Altogether, 2464 healthy infants were recruited. Two oral doses of vaccine at 104.7, 105.2 or 106.1 ffu or placebo were administered with routine immunizations at 3 and 4 months of age. Seroconversion and 'vaccine take' in the vaccine groups 1-month post dose 2 varied from 76 to 91% and 98 to 100% respectively. Vaccine was well tolerated and did not interfere with response of concomitantly administered vaccines.

A Rotavirus Vaccine for Infants: The Asian Experience

Introduction: Severe rotavirus gastroenteritis in children causes significant morbidity world- wide and substantial deaths in developing countries. Hence, a live attenuated vaccine Rotarix™ was developed with human strain RIX4414 of G1P1A P[8] specificity. RIX4414 trials in infants have begun in developed and developing countries worldwide. An overview of RIX4414 in developed and developing countries and prospects with this vaccine in Asia are presented. Methods: Completed RIX4414 trials have been reviewed. Results: Two oral doses of RIX4414 were well tolerated with a reactogenicity profile similar to placebo. RIX4414 was also highly immunogenic, e.g., in a dose-ranging study conducted in Singapore, 98.8% to100% of infants had a vaccine take after 2 doses. RIX4414 did not affect the immune response of simultaneously administered routine infant vaccines. RIX4414 significantly reduced severe rotavirus gastroen- teritis in settings where multiple serotypes including the emerging G9 type co-circulated. Conclusion: These encouraging results warrant further evaluation of the vaccine worldwide and especially in developing countries with the highest need. Therefore, evaluation of the Rotarix™ vaccine is continuing in large phase III trials in Asia and worldwide. Key words: Asia, Attenuated, Developing countries, Gastroenteritis, RIX4414

A rotavirus vaccine for infants: the Asian experience

INTRODUCTION

Severe rotavirus gastroenteritis in children causes significant morbidity worldwide and substantial deaths in developing countries. Hence, a live attenuated vaccine Rotarix was developed with human strain RIX4414 of G1P1A P[8] specificity. RIX4414 trials in infants have begun in developed and developing countries worldwide. An overview of RIX4414 in developed and developing countries and prospects with this vaccine in Asia are presented.

METHODS

Completed RIX4414 trials have been reviewed.

RESULTS

Two oral doses of RIX4414 were well tolerated with a reactogenicity profile similar to placebo. RIX4414 was also highly immunogenic, e.g., in a dose-ranging study conducted in Singapore, 98.8% to 100% of infants had a vaccine take after 2 doses. RIX4414 did not affect the immune response of simultaneously administered routine infant vaccines. RIX4414 significantly reduced severe rotavirus gastroenteritis in settings where multiple serotypes including the emerging G9 type co-circulated.

CONCLUSION

These encouraging results warrant further evaluation of the vaccine worldwide and especially in developing countries with the highest need. Therefore, evaluation of the Rotarix vaccine is continuing in large phase III trials in Asia and worldwide.

Surgical complications and outcome of paediatric liver transplantation: the Singapore experience

The purpose of this study was to analyse the early and late results of paediatric liver transplantation (LT), with particular reference to complications that required surgical intervention. The charts of all children who underwent LT between 1990 and 2002 were reviewed retrospectively. Results were analysed with a minimum follow up of 9 months. Thirty-five children have undergone 38 LTs; 22 received grafts from their parents, 16 received cadaveric organs and three children had retransplantation. The ages of the children ranged from 12 to 168 months. Biliary atresia was the most frequent indication for transplant (n=27). Twenty-seven children had complications that required surgical or radiological interventional procedures. Vascular complications included hepatic artery thrombosis (n=2), hepatic vein (HV) thrombosis (n=1), and the majority being portal vein thrombosis (n=6). Bile leaks were observed in eight children. Other complications included intestinal perforation (n=2), intra-abdominal abscesses (n=1), wound dehiscence (n=2), post-operative bleed (n=2), intestinal obstruction (n=2), ventral hernia (n=1), and multiple abdominal wound sinuses (n=1). Three children underwent retransplantation, two for hepatic artery thrombosis with multiple episodes of cholangitis and intrahepatic biliomas and the third was done for hepatic vein thrombosis. Patient and graft survival at 1 year is 81.5 and 74.2%, respectively. Paediatric LT is associated with significant morbidity, the main complications being vascular and biliary.

Paediatrics in Singapore: the early days

Paediatric services in Singapore started at the end of the 19th century. Because of inadequate housing, poor sanitation and inadequate health services, malnutrition and infections were the main problems. Infant mortality was in excess of 300/1000. There were many prominent doctors who worked in extremely demanding environments in order to better the health of children at that time. Over the years, there has been a steady improvement of healthcare in Singapore and this has been mainly due to the foresight and hard work of the pioneers. With excellent primary healthcare and specialised paediatric centres, paediatric services in Singapore are among the best in the world.

Successful listing of patients for liver transplant was related to participation of referring doctor in the transplant program

INTRODUCTION

Experience with liver transplantation is limited in many parts of Asia. Therefore, patients from nontransplant centers may not be referred in a timely fashion for transplants. Our aim was to evaluate the pattern of referral for liver transplantation and their outcomes in Singapore.

METHODS

Consecutive patients referred from 1990 to 2001 were reviewed. Patients from any hospital in Singapore (or the region) could be referred to the program. They were discussed at the weekly meetings. Appropriate patients were placed on the waiting list. "Pending" indicated that the disease was early or there were unsettled medical or social issues. Unsuitable patients were "rejected" for transplant.

RESULTS

There were 385 patients referred over a 12-year period. Hepatitis B cirrhosis and hepatocellular carcinoma (HCC) were the most common indications among adults, whereas biliary atresia was the most common for children. Pediatric patients were more likely than adult patients to be listed for transplant (53/76 vs 106/309, P < .001). Patients referred by regular attendees of the program were more likely to be accepted than nonattendees (38% vs 25%, P = .04). "Disease too early", "advanced HCC", and "refusal by family members" were the most common reasons for rejection.

CONCLUSION

Members of the Liver Transplant Program were more likely to refer suitable patients for transplant at the appropriate time. Better interaction between gastroenterologists inside and outside the transplant program would help to improve the timing of referrals for liver transplantation, and hence, patient survival.

Use of hypoallergenic formula in the prevention of atopic disease among Asian children

OBJECTIVE

To determine the effect of a partially hydrolysed formula on genetically predisposed children, with respect to the development of atopic clinical manifestations and in vitro testing of serum IgE levels (total and milk-specific).

METHODS

One hundred and ten infants were randomly assigned to receive either partially hydrolysed formula or standard infant formula, and were prospectively monitored from birth for clinical atopic symptoms and serum IgE levels.

RESULTS

Eczema occurred less frequently in infants receiving partially hydrolysed formula. This was significant (P < 0.05) at 3, 6, 9, 12, 18 and 24 months. However, the significance decreased with time, although it almost reached statistical significance at 30 months by the Kaplan-Meier survival function (log-rank statistic, 3.46; P = 0.063). Although wheezing occurred less frequently in infants receiving partially hydrolysed formula, compared to those receiving standard infant formula, the difference did not reach statistical significance (P > 0.05).

CONCLUSIONS

Exclusive feeding of hypoallergenic milk formula in the first 4 months of life has a protective effect in terms of the development of atopic dermatitis in the first 2 years of life, compared to feeding with cow's milk formula.

Liver transplantation in a child with severe hypercholesterolaemia in Alagille syndrome

INTRODUCTION

Liver transplantation is a curative treatment modality in children with end stage liver disease in Alagille syndrome.

CLINICAL PICTURE

We report a 3-year-old child with this condition who had severe hypercholesterolaemia, pruritus and extensive xanthomatosis.

TREATMENT

Liver transplantation was performed in this patient.

OUTCOME

He recovered well with normalisation of his lipid profile. This procedure also resulted in resolution of the disfiguring xanthomatosis.

Population pharmacokinetics of tacrolimus in Asian paediatric liver transplant patients

AIMS

The purpose of this study was to describe the population pharmacokinetics of intravenous and oral tacrolimus (FK506) in 20 Asian paediatric patients, aged 1-14 years, following liver transplantation and to identify possible relationships between clinical covariates and population parameter estimates.

METHODS

Details of drug dosage histories, sampling times and concentrations were collected retrospectively from routine therapeutic drug monitoring data accumulated for at least 4 days after surgery. Before analysis, patients were randomly allocated to either the population data set (n = 16) or a validation data set (n = 4). The population data set was comprised of 771 concentration measurements of patients admitted over the last 3 years. Population modelling using the nonlinear mixed-effects model (NONMEM) program was performed on the population data set, using a one-compartment model with first-order absorption and elimination. Population average parameter estimates of clearance (CL), volume of distribution (V) and oral bioavailability (F) were sought; a number of clinical and demographic variables were tested for their influence on these parameters.

RESULTS

The final optimal population models related clearance to age, volume of distribution to body surface area and bioavailability to body weight and total bilirubin concentration. Predictive performance of this model evaluated using the validation data set, which comprised 86 concentrations, showed insignificant bias between observed and model-predicted blood tacrolimus concentrations. A final analysis performed in all 20 patients identified the following relationships: CL (l h-1) = 1.46 *[1 + 0. 339 * (AGE (years) -2.25)]; V (l) = 39.1 *[1 + 4.57 * (BSA (m2)-0. 49)]; F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] and F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] * [1.61], if the total bilirubin > or = 200 micromol l-1. The interpatient variabilities (CV%) in CL, V and F were 33.5%, 33.0% and 24.1%, respectively. The intrapatient variability (s.d.) among observed and model-predicted blood concentrations was 5.79 ng ml-1.

CONCLUSIONS

In this study, the estimates of the pharmacokinetic parameters of tacrolimus agreed with those obtained from conventional pharmacokinetic studies. It also identified significant relationships in Asian paediatric liver transplant patients between the pharmacokinetics of tacrolimus and developmental characteristics of the patients.

Abdominal coarctation and Alagille syndrome

Structural cardiac defects such as peripheral pulmonary stenosis are well-described in Alagille syndrome (AS), which is transmitted in an autosomal dominant inheritance. The genetic defect, with incomplete penetrance and variable expression, is localized to the short arm of chromosome 20. Abdominal coarctation is an uncommon congenital anomaly, with a spectrum of symptoms that may range from hypertension, intermittent claudication to abdominal pain. The association of abdominal coarctation with AS is rarely described. We report such a patient who also had aberrations of the visceral vascular supply involving the celiac, splenic, and superior mesenteric arteries. The indications to treat the coarctation, and in the context of a patient with AS, in whom liver transplantation may be contemplated at some stage, merit discussion.

Esophageal intramural pseudodiverticulosis associated with a web in a 12-year-old boy

Esophageal intramural pseudodiverticulosis (EIPD) is a rare benign disorder characterized by dilation of the submucosal glands. Its etiology and pathogenesis are largely unknown. So far, less than 10 pediatric cases of EIPD have been reported. The authors present the case of a 12-year-old boy with EIPD that was associated with a cervical esophageal web. He was treated successfully with dilation therapy.

Factors associated with increased respiratory symptoms among asthmatic children in Singapore

Asthma is a common cause of childhood morbidity. The objective of the present study was to evaluate the factors associated with increased asthma morbidity among asthmatic children in Singapore. A cohort of primary school children (n = 6,404, aged 6-13 years) were evaluated using the American Thoracic Society and the Division of Lung Diseases of the National Heart, Lung and Blood Institute, USA (ATS-DLD) respiratory questionnaire. A total of 2,222 of 6,404 children (34.8%) was found to have reported symptoms of wheezing. Of these, 899/2,222 (40.5%) reported symptoms of "increased asthma morbidity". This was associated with the younger age group, male sex and higher socio-economic status. In addition, concurrent or past allergies were strongly associated with increased asthma morbidity, while premature birth and a history of prior childhood respiratory illnesses and Infections were predictive of greater asthma morbidity. No association was found between increased morbidity and presence of domestic pets, parental smoking, childcare attendance, and the season of birth.

Hepatopulmonary syndrome: a rare complication of chronic liver disease in children

An 11-year-old boy with congenital hepatic fibrosis presented with cyanosis at the National University Hospital. Echocardiogram revealed a structurally normal heart with good ventricular function. A pulmonary cause of his cyanosis was suggested on macroaggregated albumin scan and selective pulmonary artery angiogram. Arterial hypoxaemia secondary to intrapulmonary arteriovenous shunting in chronic liver cirrhosis can lead to permanent cyanosis. The potential for a complete reversal of this condition after liver transplantation indicates that arterial hypoxaemia, rather than being a contraindication, should be a reason for early liver transplantation.

Use of soy-protein formulas and soyfood for feeding infants and children in Asia

Soybeans have been cultivated and consumed in Asia for many centuries. Soy products can be found in all households in Asian countries, and Asian children begin to consume soy formulas and soy products at a very young age. In a study of soy exposure in a group of healthy Singaporean children < 10 y of age, 70% had consumed soy products and of those > 95% had consumed soy products before the age of 18 mo. Soy products are commonly used as food flavorings and for weaning Asian children with lactose intolerance or allergy to cow-milk protein. The widespread use of soy formulas and soy products by Asian children is mainly due to the high nutritive value and palatability of these products.

Month of birth and childhood atopic diseases in the tropics

The relationship between the month of birth and prevalence of diagnosed asthma, asthma-like symptoms (wheezing, nocturnal cough, and exercise wheezing), rhinitis, and eczema was investigated in four cohorts each of primary schoolchildren and secondary school (high school) adolescents in Singapore by questionnaire survey. Significantly increased prevalence rates of diagnosed asthma and asthma-like symptoms were observed in certain birth months of the year for two adolescent cohorts, while significant association between birth month and presence of symptoms of rhinitis was found in a cohort of 6-7-year-olds. However, when demographic factors were taken into consideration by multivariate analysis, only the association between asthma, asthma-like symptoms, and birth month remained significant in one of the adolescent cohorts. There was, therefore, only a weak association between the month of birth and atopic disease in our schoolchildren. The overall seasonal trends, however, did show two main seasons (March-May and September-November) associated with higher prevalence of these diseases.

Gastroesophageal reflux in preterm infants: norms for extended distal esophageal pH monitoring

BACKGROUND

Preterm infants are predisposed to gastroesophageal reflux, which may manifest itself in many ways ranging from failure to thrive to vomiting. Extended distal esophageal pH monitoring is the gold standard for diagnosing reflux in the preterm infants and it is our objective to establish extended distal esophageal pH norms (reference values) for well, asymptomatic preterm infants and to compare with norms already established for term infants, children, adolescents, and adults.

METHODS

Twenty-one well, asymptomatic preterm infants consuming at least 70% of required maintenance oral feedings were recruited. The mean +/- standard deviation birth weight was 1549 +/- 439 g (range, 670-2470 g); the mean postconceptional age was 30.7 +/- 2.6 weeks (range, 25-35 weeks) and the mean postnatal age was 14 +/- 9 days (range, 2-40 days). Extended distal esophageal pH monitoring was performed on each of the infants, and the following parameters were calculated: reflux index, number of reflux episodes per day, number of reflux episodes lasting more than 5 minutes per day, and the longest recorded reflux episode.

RESULTS

The mean reflux index was 0.7 +/- 1.1%, the mean number of reflux episodes per day was 7.6 +/- 11.2, the mean number of reflux episodes lasting more than 5 minutes per day was 0.5 +/- 1.1 and the mean longest recorded reflux episode was 4.2 +/- 6.1 minutes. These results were comparable to those seen in term infants, children, adolescents, and adults. The trends for pH norms according to postconceptional age and postnatal age seemed to suggest that lower esophageal sphincter maturation might be related to postconceptional age, but the differences observed were not statistically significant (p > 0.05).

CONCLUSION

The norms (reference values) for well, asymptomatic preterm infants were comparable to those seen in term infants, children, adolescents, and adults. With the establishment of these norms, the search for a causal link between many of the respiratory problems encountered in prematurity and gastroesophageal reflux may be aided and the complications associated with gastroesophageal reflux may consequently be reduced.

Liver transplant in Singapore--coming of age

BACKGROUND/AIM OF STUDY

Liver transplantation was first performed in 1967, and has become an accepted form of treatment worldwide for chronic liver diseases, acute liver failure and certain metabolic diseases. We document our experience in Singapore over the last 7 years since the first transplant was performed in 1990.

METHOD

Retrospective study at National University Hospital, Singapore.

RESULTS

Twenty-two operations (10 paediatric and 12 adults) have been performed with the last 17 having been performed in the last 17 months. Currently, there are 15 survivors (68%) since 1990, and percentage survival is even better if one considers the cases from the last 17 months when the majority of cases (17 transplants-77%) were performed (77% survival). The most common indication for transplant was biliary atresia for the paediatric group, while the adults were transplanted for hepatitis B and C cirrhosis, primary biliary cirrhosis, and fulminant liver failure. Tacrolimus is the main immunosuppression (10 patients), with the remaining 5 patients on cyclosporine. Various surgical techniques (living donor, graft reduction) have been employed successfully to provide a complete transplant service. Hospital and ICU stays are within normal limits and the hospital charges range from a low of S$30,000 to S$141,000.

CONCLUSION

Liver transplantation has become a reality in Singapore with outcomes comparable to other transplant centres. The shortage of donors remains the greatest stumbling block for further expansion.

Racial differences in Helicobacter pylori seroprevalence in Singapore: correlation with differences in peptic ulcer frequency

The aim of this study was to determine, first, whether racial differences exist in the seroprevalence of Helicobacter pylori infection in Singapore, and second, whether these differences correlate with racial differences in peptic ulcer frequency. A commercial serological test for immunoglobulin (Ig)G antibody to H. pylori which was 90% sensitive and 83% specific in our population was used to screen 403 adult blood donors of Chinese, Malay and Indian origin, aged between 15-60 years. Serum specimens from 84 paediatric patients admitted to the Paediatrics Department, National University of Singapore, with non-gastroenterological illnesses were also tested. In all three races, seroprevalence of H. pylori increased with age. Indians have the highest prevalence of infection followed by Chinese and Malays. Peptic ulcer prevalences are known to be highest in Chinese, followed by Indians and Malays. The Malays have the lowest prevalence of H. pylori and peptic ulcer among the three races in Singapore. Indians have a higher prevalence of H. pylori antibodies but a lower frequency of peptic ulcer than the Chinese. Racial differences in peptic ulcer frequency between Chinese and Indians are not explained by the prevalence of H. pylori infection; other environmental or genetic factors may be involved.

Presence of domestic pets and respiratory symptoms in asthmatic children

The allergens of domestic pets such as cats, dogs and birds, have been known to sensitive predisposed individuals. In Singapore, approximately 25% to 35% of our atopic populations are sensitised to cat, dog or bird feather allergens. It is not known, however, if the presence of such domestic pets would translate to higher rates of sensitisation, or more importantly, give rise to increased respiratory symptoms. This study evaluated the association between the presence of domestic pets at home and the prevalence of respiratory symptoms among asthmatic children in Singapore. The parents of 1517 doctor-diagnosed asthmatic children were interviewed using the American Thoracic Society-Division of Lung Diseases respiratory questionnaire. More than 20% were found to have domestic pets (cats, dogs or birds) at home. Of these, those with exposure to passive smoke in the home were excluded. A total of 188 current pet owners (cats, dogs and birds) were demographically-matched for sex, race and socio-economic status (type of housing) to those without pets, past or current. Compared to those without pets, asthmatic children with pets at home had a higher prevalence of coughing with cold [relative risk (RR) 1.30; 95% confidence interval (CI) 1.01 to 1.69]; wheezing with cold (RR 1.42; CI 1.07 to 1.90), wheezing with shortness of breath (RR 1.33; CI 1.00 to 1.82), exercise-induced wheezing (RR 1.68; CI 1.10 to 2.56); and increased phlegm production or congestion with cold (RR 1.38; CI 1.00 to 1.91). This study suggests that the presence of domestic pets increases the prevalence of respiratory symptoms in asthmatic children. Those with predisposition to these allergens should avoid having these pets in the home or take specific precautions in avoiding their allergens.

Glucose-6-phosphate dehydrogenase deficiency in Singapore

Glucose-6-phosphate dehydrogenase (G6PD) in man is an X-linked enzyme. The deficiency of this enzyme is one of the most common inherited metabolic disorders in man. In Singapore, three clinical syndromes associated with G6PD deficiency had been described: severe haemolysis in neonates with kernicterus, haemoglobinuria and "viral hepatitis"-like syndrome. The human G6PD monomer consists of 515 amino acids. Only the tetrameric or dimeric forms composed of a single type subunit are catylitically active. The complete amino acid sequence of G6PD had been elucidated in man and various other animals. The region of high homology among the enzymes of various animals is presumably functionally active. Among the Chinese in Singapore, three common molecular variants had been identified: Canton (nt 1376 G --> T), Kaiping (nt 1388 G --> A) and Mediterranean (nt 563 C --> T) in frequencies of 24%, 21% and 10% respectively. In addition, two common mutants (Gaozhou, nt 95 A --> G and Chinese 5, nt 1024 C --> T) have been detected in Singapore Chinese in low frequencies. In Malays, 6 different deficient variants are known in Singapore (3 new, 1 Mahidol, 1 Indonesian and 1 Mediterranean).

Lung function reference values in Singaporean children aged 6-18 years

BACKGROUND

A study was undertaken to produce reference values of lung function in Chinese children and a means of calculating adjusted standard deviation scores of lung function for Malay and Indian ethnic groups.

METHODS

A cross sectional study of lung function (forced expiratory volume in one second and forced vital capacity) measured with a Jaeger spirometer was performed in a representative sample of Singaporean children made up of 1403 Chinese, 335 Malays, and 206 Indians.

RESULTS

The relation between natural logarithms of lung function and height was approximately linear until 150 cm in boys and 140 cm in girls. At these heights there were abrupt changes in the gradients of both lines. Separate regression lines were derived for heights above and below these inflection points. Significant differences in lung function were seen in Chinese compared with Malay and Indian children. In particular, values were considerably lower among Indian boys.

CONCLUSIONS

The relation between lung function and height in Chinese children is best described by two regression equations over separate height ranges. Information is provided for the calculation of reference values and standard deviation scores, together with the correction factors that need to be applied to derive these values in Malay and Indian children.

Helicobacter pylori infection in children with recurrent abdominal pain

Forty-eight patients with recurrent abdominal pain were studied endoscopically for the presence of gastritis and Helicobacter pylori infection. Fifteen of these children had histological evidence of gastritis with eight of them having concomitant H. pylori infection. The majority of those with H. pylori infection had severe degrees of acute following chronic gastritis.

The nature of small bowel luminal fluid lactase

The evidence indicating a mucosal source for the jejunal fluid lactase activity of children is so far inconclusive. Samples of jejunal mucosa and the adjacent fluid were obtained simultaneously from 15 children. Lactase activity was measured at pH 5.9 in mucosa and fluid. Fluid activities showed a significant positive correlation with the activity of the corresponding mucosal homogenate but a stronger correlation was found with an enterocyte microvillous membrane fraction prepared from the same homogenate (r = 0.807 and 0.889, respectively). Kinetic and pH optima studies were consistent with a microvillous membrane origin. Fluid activity and pH optimum were not changed detectably when measured in the presence of an enterocyte lysosomal acid lactase inhibitor. Jejunal fluid lactase activity and its properties closely reflect the microvillous membrane enzyme. Lysosomal acid lactase does not contribute measurably to the total lactase activity of jejunal fluid.

Pre-liver transplantation management of children

Liver transplantation is the accepted treatment for children with end-staged liver diseases nowadays. Currently, the five year actuarial survival rate is about 80%. In children, the most common indication for transplantation is biliary atresia. Due to shortage of donor organs, portoenterostomy is still the initial treatment of choice for young infants with biliary atresia. This will enable the affected infants to continue growing until a suitable donor organ is available. There are a few absolute contraindications to liver transplantation in children. Severe irreversible disease in any other organs and poor psychosocial support are indications for not performing liver transplantation. Appropriate pre-operative assessment and preparations are necessary for a successful transplant. Post-operative course may be marred by rejection, infections and surgical complications. Long term immunotherapy is necessary.

Gastrointestinal infections in Singapore children

Acute gastroenteritis is the commonest gastrointestinal disorder in children. It accounted for about 10% of the admissions to a general paediatric unit in Singapore. About 5% of total paediatric admissions to all the government hospitals in Singapore were due to acute gastroenteritis. Some 50% of the cases had no identifiable organism in the stools. Most of the remaining cases were due to bacterial or viral infections. The commonest bacteria responsible for acute gastroenteritis nowadays is Salmonella species. Other bacteria such as E. coli, Shigella and Campylobacter were responsible for a smaller proportion of bacterial diarrhoea in children. Rotavirus was the commonest viral agent responsible for acute diarrhoea among Singapore children. Most patients had mild diarrhoea and severe dehydration following acute gastroenteritis was not common. About 60% of the patients admitted to hospital were younger than two years of age. Bacterial infections were more common in infancy. Viral diarrhoea were more likely to be watery and bacterial diarrhoea were more likely to be bloody and mucoid. With regard to chronicity, it was the groups with mixed infection or bacteria infection which had a prolonged course. Treatment was directed at maintaining hydration and prevention of complications. Except for secondary lactase deficiency, other long term complications were rare.

Cell-mediated immunity in patients on hemodialysis: relationship with hepatitis B carrier status

We compared cell-mediated immune responses in two groups of patients on hemodialysis. One group of patients were chronic carriers of hepatitis B virus (HBV), and the patients of the other group were HBV antigen negative. Our results show that despite the presence of normal numbers of T cells and an increased CD4/CD8 ratio in both groups of patients compared to healthy controls (p less than 0.0001), only the group of patients who were chronic HBV carriers showed depressed lymphoproliferative responses to phytohemagglutinin (p less than 0.001) and concanavalin A (p less than 0.0001). In contrast, a control group of healthy adult HBV carriers showed normal T cell subsets and lymphoproliferative responses to mitogens, indicating that HBV infection per se did not result in depressed lymphoproliferative responses. These results further substantiate the notion that depressed cell-mediated immunity in chronic renal failure is an important factor in predisposing patients to HBV infection with subsequent development of the chronic carrier state.

Colonoscopy in children with bleeding per rectum

There are few reports of colonoscopy in children. Twenty-six children with bleeding per rectum were examined colonoscopically to determine the aetiology of the bleeding. A total of 32 colonoscopies were performed. Except for 5 children who needed general anaesthesia, all the rest were performed with pethidine and diazepam sedation. The mean age of these 26 children was 63.5 months (SD 57.5 months, range 2 weeks to 180 months). Ten children had histologically confirmed colitis. Five had bleeding juvenile polyps and these were removed endoscopically. One had lymphoid hyperplasia and one had chronic solitary sigmoid ulcer. The rest were normal. It is concluded that colonoscopy can be performed safely in children and it is a good diagnostic and therapeutic procedure.

Upper gastrointestinal endoscopy in children

The purpose of this paper is to study the use of upper gastrointestinal (Gl) fiberoptic endoscopy in children. Two hundred consecutive patients referred to one of the authors were reviewed. The indications for performing upper gastrointestinal endoscopy in these 200 patients were: (1) recurrent abdominal pain (46.5%), (2) persistent vomiting (14.5%), (3) haematemesis (14.5%), (4) acute abdominal pain (13%) and (5) other indications such as foreign body removal, failure to thrive and unexplained chest pain (11.5%). The endoscopy was performed with the Olympus P3 or Olympus XP-10 gastroscopes. The sedation used was a combination of intravenous pethidine (2mg/kg) and diazepam (0.5 mg/kg). Among the patients with recurrent abdominal pain, upper Gl endoscopy showed duodenal ulcer in 7 patients (7.5%), duodenitis in 4 (4.3%), oesophagitis in 4 (4.3%) and gastric ulcer in 2 (2.2%). The rest of the patients were normal (81.7%). With regard to persistent vomiting, 37.9% of the patients showed gastroesophageal reflux and 6.9% had a hiatus hernia. Of 29 patients examined endoscopically for upper Gl bleeding, no focus of bleeding was identified in 27.6%. The remaining 72.4% were bleeding from acute gastric erosion (27.6%), oesophagitis (17.2%), oesophageal varices (13.8%), duodenal ulcer (10.3%) and Mallory-Weiss tear (3.5%). The Majority of the patients with acute abdominal pain were normal endoscopically (61.5%). The two common abnormal findings were acute gastritis (27.0%) and acute duodenitis (11.5%). No major complications were encountered during the procedure in these 200 patients. It was concluded that upper Gl endoscopy is useful for defining upper Gl mucosal pathology. The procedure can be performed safely in children under sedation.

Incidence, clinical features and epidemiology of rotavirus gastro-enteritis in hospitalized children

Two hundred and eighteen patients with acute gastro-enteritis (GE) and 67 controls (patients admitted during the period of study for illness other than (GE) were included in this study. Their stool samples were subjected to the following tests to detect the presence of rotavirus: enzyme-linked immunosorbent assay (ELISA), latex agglutination and electron microscopy. Samples positive by any one or more of the above methods were considered positive for rotavirus and were subjected to polyacrylamide gel electrophoresis of viral RNA. Rotavirus was detected in 59 (27.1%) of the 218 GE samples and four (6%) of the control samples. ELISA was the most sensitive test and could detect viral antigen long after the other methods failed to do so.

Accuracy of anorectal manometry in the diagnosis of Hirschsprung's disease

The value of anorectal manometry as a diagnostic tool for Hirschsprung's disease (HD) was assessed in 50 children presenting with chronic constipation. Anorectal manometric studies and rectal biopsy were performed on all children. Biopsy specimens were stained with hematoxylin and eosin and serial sections were examined for ganglion cells. Forty-five children had concordant manometric and histologic results, 15 of whom were positive for HD and 30 negative. In five children, the results were discordant. Using histologic aganglionosis as the reference point for the final diagnosis of HD, the overall accuracy of anorectal manometry as a discriminative test was 90.0%. The sensitivity, specificity, and positive and negative predictive values of manometric studies for the diagnosis of HD were 0.79, 0.97, 0.94, and 0.88, respectively. Factors responsible for the inaccuracies of manometric studies are discussed.

Oral refeeding following acute gastro-enteritis: a clinical trial using four refeeding regimes

A clinical trial using four different oral refeeding regimes was conducted in 100 patients following acute gastro-enteritis. There was no difference in terms of the diarrhoea-relapse rates among the four groups of patients. However, a better weight gain was recorded in the groups using a lactose-free soy formula and a low-lactose low-fat cow's milk formula.