Seng Hock Quak

Safety and efficacy of human rotavirus vaccine during the first 2 years of life in Asian infants: Randomised, double-blind, controlled study

This study evaluates the safety and efficacy against severe rotavirus gastroenteritis of the oral live attenuated human rotavirus vaccine RIX4414 (Rotarix) during the first 2 years of life in Asian infants from high-income countries. Healthy infants were enrolled to receive 2 doses of RIX4414 (N=5,359) or placebo (N=5,349). From 2 weeks post-dose 2 to 2 years of age, vaccine efficacy was 96.1% (95%CI:85.1%; 99.5%) against severe rotavirus gastroenteritis, 100% (95%CI:80.8%; 100%) against wild-type G1P[8] and 93.6% (95%CI:74.7%; 99.3%) against circulating non-G1 rotavirus types. No intussusception cases were reported within 31 days post-vaccination. RIX4414 shows a good safety profile and offers high protection during the first 2 years of life with potentially significant public health impact in this population.

Population pharmacokinetics of tacrolimus in whole blood and plasma in asian liver transplant patients.

ObjectivesThe objectives of this study were to develop population pharmacokinetic models of tacrolimus in an Asian population with whole blood and plasma drug concentration data, to compare the variability of the pharmacokinetic parameters in these two matrices and to search for the main patient characteristics that explain the variability in pharmacokinetic parameters.Study designProspective pharmacokinetic assessment followed by model fitting.PatientsWhole blood samples from 31 liver transplant patients in a local hospital receiving oral tacrolimus as part of their immunosuppressive therapy were assessed. Plasma samples from 29 of the 31 patients were also evaluated. Concentrations of tacrolimus in whole blood and plasma were determined by an electrospray high-performance liquid chromatography with tandem mass spectrometry. Two hundred and thirteen whole blood and 157 plasma tacrolimus concentrations were used for building two nonlinear mixed-effects population models to describe the disposition of tacrolimus in whole blood and plasma, respectively. Covariates that were investigated included demographic characteristics, biological markers of liver and renal functions, corticosteroid dose and haematological parameter.ResultsA one-compartment model was used to describe the whole blood and plasma concentration-time data of tacrolimus after oral administration. For the whole blood population model, the population estimates of the first-order absorption rate constant (ka), apparent clearance based on whole blood concentration after oral administration (CLB/F) and apparent volume of distribution based on whole blood concentrations after oral administration (Vd,B/F) were 2.08h−1, 14.1L/h and 217L, respectively. The coefficient of variations (CVs) of interpatient variabilities in CLB/F and Vd,B/F were 65.7% and 63.8%, respectively. Bodyweight, liver and renal function influenced CLB/F, while height and haematocrit influenced Vd,B/F. The residual (unexplained) variability was 34.8%. For the plasma population model, the population estimates of the ka, apparent clearance based on plasma concentrations after oral administration (CLp/F) and apparent volume of distribution based on plasma concentrations after oral administration (Vd,p/F) were 5.21h−11, 537 L/h and 563L, respectively. The CVs of interpatient variabilities in CLp/F and Vd,p/F were 96.0% and 105.4%, respectively. Bodyweight was found to influence CLp/F, while the erythrocyte-to-plasma concentration ratio influenced Vd,p/F. The residual (unexplained) variability was 49.8% at the mean plasma concentration of 1.1 ng/mL.ConclusionsWhole blood and plasma population pharmacokinetic models of tacrolimus in Asian adult and paediatric liver transplant patients were developed using prospective data in a clinical setting. This has identified and quantified sources of interindividual variability in CLB/F, Vd,B/F, CLp/F and Vd,p/F of tacrolimus in Asian liver transplant patients. Information derived from the whole blood population model may subsequently be used by clinicians for dosage individualisation through Bayesian forecasting.

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.

Rotavirus vaccine RIX4414 efficacy sustained during the third year of life: a randomized clinical trial in an Asian population.

RIX4414 (Rotarix™), has shown high efficacy during the first 2-years of life. A 2-year randomized, double-blind, placebo-controlled trial in Singapore, Hong Kong, and Taiwan was extended for another year. Infants (6-17 weeks) received 2-doses (1-2 months apart) of RIX4414 (n=5359) or placebo (n=5349). During the third-year follow-up, 4359 (RIX4414) and 4328 (placebo) infants were monitored. 64 (1.2%) and 2 (0.04%) infants in the placebo and RIX4414 groups, respectively, reported severe rotavirus-gastroenteritis (RVGE), resulting in a vaccine efficacy of 96.9% (95% CI [88.3-99.6]). Efficacy was 100% (67.5-100) in the third-year. RIX4414 was efficacious against G1 (100.0% [84.8-100]) and pooled non-G1 RV types (94.9% [80.2-99.4]). This study shows that the vaccine is highly efficacious, regardless of circulating RV-types, up to the first 3 years of life in affluent Asian urban populations.

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.

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.

Immune Responses to Differentiated Forms of Helicobacter pylori in Children with Epigastric Pain

ABSTRACT Helicobacter pylori infection affects human populations of all ages. This gastric bacterium exists in spiral form and the reported viable but nonculturable coccoid form. The present study aims to examine the probable role of the coccoid form in H. pylori infection by comparing the seroprevalences of the spiral and the coccoid forms in children with epigastric pain. Four hundred eighty-nine children (mean age, 8.5 years) with epigastric pain formed the basis of this study. Five hundred ninety-nine schoolchildren of comparable ages and with no record of dyspepsia served as controls. The seroprevalence of antigens prepared from both morphological forms was examined by enzyme-linked immunosorbent assay. The results showed that 65 (13.3%) and 273 (55.8%) of 489 symptomatic children were seropositive for antigens of the H. pylori spiral and coccoid forms, respectively. In contrast, only 7.0% of the control group had elevated levels of immunoglobulin G antibodies against the spiral form, while 26.5% were positive for antibodies against the coccoid form. There were no significant differences between genders or among ethnic groups. The study showed a rise in seroprevalence corresponding with age: 7.1% for those ≤5 years to 21.4% for those ≥11 years. The seroprevalence of antigens of the H. pylori spiral and coccoid forms in children with epigastric pain was twofold higher than that in the control subjects. Interestingly, there was a fourfold increase in seropositivity for coccoid-form antigen compared to that for the spiral-form antigen among the symptomatic pediatric patients as well as the control group, indicating a possible infective role of the coccoid form of H. pylori in the pediatric patients with epigastric pain.

Cyclical vomiting syndrome: Recognition, assessment and management

Cyclical vomiting syndrome (CVS) is a functional, debilitating disorder of childhood frequently leading to hospitalization. Affected children usually experience a stereotypical pattern of vomiting though it may vary between different individuals. The vomiting is intense often bilious, and accompanied by disabling nausea. Identifiable precipitating factors for CVS include psychosocial stressors, infections, lack of sleep and occasionally even food triggers. Often, it may be difficult to distinguish episodes of CVS from other causes of acute abdomen and altered consciousness. Thus, the diagnosis of CVS remains largely one of exclusion. Investigations routinely done during the work-up of a child with suspected CVS include both blood and imaging modalities. Plasma lactate, ammonia, amino acid and acylcarnitine profiles as well as urine organic acid profile are indicated to exclude inborn errors of metabolism. The treatment remains challenging and targeted at prevention or shortening of the attacks and can be considered as abortive, supportive and prophylactic. Use of non-pharmacological therapy is also part of the management of CVS. The prognosis of CVS is variable. More insight into the pathogenesis of this disorder as well as role of non-pharmacological therapy is needed.

Costs associated with functional gastrointestinal disorders and related signs and symptoms in infants: a systematic review protocol

Introduction Functional gastrointestinal disorders (FGIDs) and FGID-related signs and symptoms have a fundamental impact on the psychosocial, physical and mental well-being of infants and their parents alike. Recent reviews and studies have indicated that FGIDs and related signs and symptoms may also have a substantial impact on the budgets of third-party payers and/or parents. The objective of this systematic review is to investigate these costs. Methods and analysis The population of interest is healthy term infants (under 12 months of age) with colic, regurgitation and/or functional constipation. Outcomes of interest will include the frequency and volume of reported treatments, the cost to third-party payers and/or parents for prescribed or over the counter treatments, visits to health professionals and changes in infant formula purchases, and the loss of income through time taken off work and out of pocket costs. Relevant studies will be identified by searching databases from 2005 onwards (including MEDLINE, EMBASE, PsycINFO, NEXIS, DARE, Health Technology Assessment database, National Health Service Economic Evaluation Database and others), conferences from the previous 3 years and scanning reference lists of eligible studies. Study selection, data extraction and quality assessment will be conducted by two independent reviewers and disagreements resolved in discussion with a third reviewer. Quality assessment will involve study design-specific checklists. Relevant studies will be summarised narratively and presented in tables. An overview of treatments and costs will be provided, with any geographical or other differences highlighted. An assessment of how the totals for cost differ across countries and elements that contribute to the differences will be generated. Ethics and dissemination This is a systematic review of published studies that will be submitted for publication to a peer-reviewed journal. Ethical committee approval is not required. Trial registration number CRD42016033119.

Endoscopic Evaluation in Children With End-Stage Liver Disease-Associated Portal Hypertension Awaiting Liver Transplant.

Objectives: Routine oesophago-gastro-duodenoscopy (OGD) pre-liver transplantation (LT) for evaluation and management of gastrointestinal (GI) pathology, in particular GI varices secondary to portal hypertension, is common practice in adult LT programmes. There is no universal consensus for this practice in children. We report our endoscopic experience in children with end-stage liver disease (ESLD) pre-LT. Methods: Retrospective audit of LT database and review of OGD findings of patients who had undergone endoscopy preceding LT. Results: Of 69 patients with ESLD, 50 (72.4%) had pre-LT OGD, 37 of which were done electively, whereas the remaining 13 were event driven. Forty-eight (96%) patients who underwent OGD had abnormalities, in which 38 (76%) patients had varices and 23 (46%) had portal hypertensive gastropathy. Eleven (22%) patients required therapeutic intervention at initial OGD either with endoscopic variceal band ligation or endoscopic sclerotherapy. Compared with the group who underwent elective OGDs, the group who had event-driven OGDs had a significantly higher requirement for endoscopic intervention (P < 0.0001), occurrence of rebleeding (P < 0.029) and requirement for repeat OGDs (P = 0.014). There was no significant difference in terms of patient (P = 0.2746) or graft survival (P = 0.3192) between the 2 groups. Conclusions: The role of pre-LT OGDs in patients with ESLD associated with portal hypertension is possibly limited to control of bleeding during episodes of GI bleed, where the aim would be to stabilize the patient until eventual LT. Multicentre prospective studies are required to provide more evidence on the use of routine endoscopy for pre-LT assessment in children.