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S H Quak

Publications and source records attributed to S H Quak.

At least 19 recordsLinked to original sources
PubMed2006

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.

Antibodies, Viral↗
PubMed2006

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.

Asia↗
PubMed2006

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.

Adolescent↗
PubMed2006

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.

Adolescent↗
PubMed2006

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.

Adult↗
PubMed2005

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.

Adolescent↗
PubMed2005

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.

History, 19th Century↗
PubMed2004

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.

Adult↗
PubMed2002

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.

Child↗
PubMed2001

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.

Alagille Syndrome↗
PubMed2000

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.

Asia↗
PubMed2000

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.

Alagille Syndrome↗