Analysis of the in vitro replication phenotype of African hepatitis B virus (HBV) genotypes and subgenotypes present in Australia identifies marked differences in DNA and protein expression

Hepatitis B virus infection in Africa is characterised by distinct genotypes with observed differences in natural history and clinical outcomes. Replication-competent cDNA clones of African genotypes were generated from patient-derived sequences identified in African children with chronic hepatitis B infection living in Australia: A1 (wild-type and basal core promotor (BCP) mutant), D2, D6, and E, comparing the replication phenotype to an established D3 cDNA clone in a transient transfection cell culture model. All clones replicated efficiently although less than the European D3 reference clone, and demonstrated marked differences in replication capacity, highest for subgenotypes A1 and D2. The BCP mutation increased the replication levels of the A1 subgenotype compared to wild-type. Intracellular and secreted surface antigen and HBeAg protein expression also varied across genotypes. We observed differences in functional activity in the upstream regulatory region across the genotypes that may contribute to the replication and protein differences observed.

Introduction and Audit of Intravenous Paracetamol at a Tertiary Paediatric Teaching Hospital

Although intravenous (IV) paracetamol is an attractive analgesic, there is little information on its paediatric use. During an introduction phase with limited prescribing rights, an audit was performed to assess its use and cost impact at a tertiary paediatric centre. Patients receiving IV paracetamol prescribed by two pain specialists for restricted indications had their medical records retrospectively reviewed for age, weight, diagnosis, indications/dose for IV (and other route) paracetamol/other analgesics/antiemetics, vomiting/oral intake and liver function tests if performed. One-hundred-and-twenty-one children and five neonates received 1216 (median 8 each) doses of paracetamol IV. Audited expenditure for IV paracetamol was 3.9 times the rectal alternative ($3435 vs. $875). Indications were appropriate, with 97% of patients nil oral, 41% vomiting, 17% having rectal route replaced and 3% avoiding parenteral morphine. Only five patients received incorrect dosing: three through prescription errors and two as guideline deviations; none were considered dangerous. No liver function test derangements could be directly attributed to paracetamol.

This data facilitated our application to extend prescribing rights for IV paracetamol within our institution. As there is limited information or local experience with the use of IVparacetamol in paediatric settings in Australia, our data may be of use to other centres considering the introduction of the IV form of this agent.

Intestinal Failure and Transplant: The Australian Experience (2009 to 2014)

BACKGROUND

A joint adult and pediatric intestinal transplant (ITx) program for Australia was developed in 2009 to provide life-saving ITx to patients with irreversible intestinal failure (IF). We aimed to analyze the outcomes of patients treated by our service over the past 5 years.

METHODS

A retrospective medical record review was conducted on all IF patients referred to our service. Patient demographics, underlying disease, nutrition support, TPN complications, and current transplant program status were evaluated.

RESULTS

Fifty-seven patients (35 adults, 40.4 ± 12.4 years; 22 children, 6.3 ± 4.3 years) throughout Australia and New Zealand have been referred. Leading causes of IF were short bowel syndrome followed by pseudo-obstruction. Forty patients (70%) exhibited at least 1 life-threatening complication of PN at referral: liver failure, impending loss of venous access, and/or recurrent line sepsis. Three patients have undergone ITx with 100% survival (median follow-up, 1161 days). Four patients (8%) are listed for transplant, 6 patients (12%) are awaiting transplant assessment, and 4 patients (8%) have died (2 while awaiting transplantation, 2 during assessment period). Causes of death included sepsis and intracranial bleed. Two-thirds of all referred patients (n = 40) were deferred or rejected from wait-listing.

CONCLUSIONS

After 5 years of establishing the first dedicated ITx program in Australia and New Zealand, early results indicate that ITx is an available and life-saving option for IF patients in these countries. Current barriers to ITx in Australia include a shortage of appropriate donors and a high rate of donor-specific antibodies among potential recipients. Growing awareness of the service and early referral to assist appropriate patient selection will aid in the program's success.

Alternative technique for transjugular intrahepatic portosystemic shunt in a young child

Liver transplantation is safer, more readily available and is increasingly being carried out in younger patients. Therapeutic bridging procedures such as transjugular intrahepatic portosystemic shunt have therefore become more relevant to paediatrics, especially in the group of patients who are too unstable for surgery or in whom a liver graft is not available. We describe a transjugular intrahepatic portosystemic shunt procedure in a 4-year-old child with life-threatening variceal bleeding in whom the conventional procedure had failed. This technique may provide an alternative to conventional transjugular intrahepatic portosystemic shunt in this group.

Antimicrobial resistance in Helicobacter pylori isolates from children

OBJECTIVE

To determine the resistance rate to four antimicrobial agents commonly used in the treatment of Helicobacter pylori infection in children.

METHODS

Between July 1997 and January 2000, all H. pylori isolates from children undergoing gastroscopy were prospectively collected and subcultured to yield the susceptibility to four antimicrobial agents by E-test. In all, 23 isolates were tested. Demographic data, presenting symptoms, treatment regimen and clinical improvement after treatment were collected retrospectively.

RESULTS

The resistance rate of H. pylori to metronidazole and clarithromycin were 43.5% and 8.7%, respectively. No H. pylori strains were resistant to amoxycillin or tetracycline. There were no statistically significant differences in age, sex, ethnicity, presenting symptoms or clinical improvement after treatment between antimicrobial-susceptible and antimicrobial-resistant groups.

CONCLUSIONS

The frequent resistance of H. pylori to metronidazole and moderate resistance to clarithromycin in children are comparable with local adult data. The incidence of resistance tended to be higher in patients of non-European ethnicity, but this was not statistically significant. Given that the primary goal of therapy is eradication, and that local resistance rates are high, recommendations for H. pylori management may need to be modified to include sensitivity testing and/or determination of eradication in all patients.

Paediatric liver transplantation [corrected] in Melbourne: the first 50 patients

To report the outcomes of the first 50 paediatric patients who have undergone liver transplantation (LT) at the Victorian Liver Transplant Unit, a retrospective review of case records was carried out. From December 1988 to December 2000, 108 patients 18 years or younger were referred for LT; 50 of these underwent a total of 53 transplants. The most common indications were biliary atresia (32%), metabolic disease (26%), and acute hepatic necrosis (26%). The majority of deaths (6/7) occurred in the 1st week after LT. The actuarial survival at 1 year was 88% (95% CI 75% to 94%) and at 10 years 85% (95% CI 71% to 93%). Survival rates were highest for children aged 3 to 14 years (95%) and lowest in those weighing less than 8 kg at the time of LT (66%). All 43 survivors are attending age-appropriate activities including kindergarten, school, and employment. The survival of patients undergoing LT in this unit compares favourably with those recorded by the Australia and New Zealand Transplant Registry and is commensurate with that reported by larger paediatric transplant programs overseas.

Long-term outcome of autoimmune hepatitis in children

BACKGROUND AND AIM

Autoimmune hepatitis (AIH) is a chronic disease of unknown etiology, which usually progresses to cirrhosis if not diagnosed and treated promptly. Data on long-term follow up in children with AIH are scant. The aim of this study is to assess the long-term outcome of autoimmune hepatitis in children with respect to clinical and laboratory features at presentation.

METHODS

Data were extracted from the medical records of patients presenting over a 28-year period (1972-2000) to the Royal Children's Hospital, Melbourne, Australia. Additional information was obtained by interviewing patients, and their current physicians. Of the 30 patients (22 females, mean age 9 years) identified, 18 had type I, three had type II, four had autoimmune-polyendocrinopathy syndrome type 1, one had infantile giant-cell hepatitis associated with Coomb's-positive hemolytic anemia, and four were seronegative (antinuclear antibody (ANA), smooth muscle antibody (SMA) and liver-kidney microsomal antibody (LKM)).

RESULTS

Clinical features at presentation included hepatomegaly (86%), jaundice (66%) and splenomegaly (50%). Initial investigations revealed a median serum bilirubin level of 55 micromol/L (range 6-425), median aspartate aminotransferase level of 678 IU (range 70-2548), and abnormal clotting in 33% of patients. Liver biopsies were performed on all patients at presentation and 11 showed cirrhosis (36%). The mean follow-up period was 10.0 +/- 7.8 years with 43% being followed for > 10 years. Only two patients died and one required transplantation. Fourteen (50%) patients continue to be on low dose prednisolone with azathioprine, two (7%) are on prednisolone alone, and six (21%) are on no therapy. When the cirrhotic and non-cirrhotic patients were compared, the albumin level at presentation was significantly lower in the cirrhotic group (P=0.01). Of the patients who were cirrhotic at presentation, six (54%) remain compensated with a mean follow-up period of 8 years. All 24 patients currently under follow up are engaged in age-appropriate activities including school, part- or full-time work.

CONCLUSION

Autoimmune hepatitis has a favorable long-term outcome with a transplant-free survival rate of 90% over a mean period of 10.0 +/- 7.8 years (range: 0.5-23), and a normal or near-normal lifestyle irrespective of presenting clinical, laboratory or histological features.

Possible roxithromycin-induced fulminant hepatic failure in a child

A pediatric formulation of roxithromycin is a relatively new addition to the antibiotic market in Australia. A previously healthy 5-year-old boy with no significant medical history was treated with roxithromycin 50 mg twice/day for cough, fever, and anorexia. After completing a 5-day course of the agent, he developed a nonpruritic, nonurticarial, erythematous, maculopapular, generalized rash and occasional vomiting. Three days later his symptoms included jaundice, dark urine, and pale stools. Laboratory results revealed acute hepatitis, and the patient was admitted to the hospital. His hepatic function continued to deteriorate, so the boy was transferred to a tertiary pediatric hospital. His condition continued to worsen, and 6 days after transfer, he underwent liver transplantation. Clinicians should be aware of potential hepatic complications associated with the use of roxithromycin.

Botulinum toxin for achalasia in children

BACKGROUND

Injection of botulinum toxin (BTx) into the lower esophageal sphincter (LES) of adult patients with achalasia results in the effective relief of symptoms. The aim of the present study was to examine the effectiveness of BTx in pediatric patients suffering from achalasia.

METHODS

Seven patients suffering from achalasia with or without prior treatment were treated with intrasphincteric injection of BTx. The median duration of follow up was 15 months.

RESULTS

All seven patients improved. The median interval before recurrence of symptoms was 4 months (range 1-14 months). There was an inverse relationship between the pretreatment LES pressure and the duration of response (r=-0.6). The mean pretreatment LES pressure in the subgroup with a response greater than 6 months was 38+/-10 mmHg compared with 61+/-12 mmHg in the other four patients (P= 0.05). All seven patients required retreatment.

CONCLUSION

Botulinum toxin is effective in relieving symptoms in pediatric patients suffering from achalasia, producing a sustained response beyond 6 months in 43% of patients.

Hepatitis C infection in children: a Melbourne perspective

OBJECTIVE

To examine the clinical spectrum of hepatitis C virus (HCV) infected children in our care by determining presentation, mode of acquisition, degree of co-infection, biochemical evidence of persisting hepatitis and treatment outcome.

METHODOLOGY

A retrospective review of the medical records of all children attending the Royal Children's Hospital, Melbourne, between 1990 and 1998, who had antibodies to HCV infection detected. Detailed clinical information, investigations and the results of treatment were extracted from the clinical notes.

RESULTS

A total of 94 children (age range 2 weeks to 19.7 years) were identified, of whom nine had passive transfer of maternal antibodies from HCV-positive mothers and were excluded from analysis. Sixty-seven children (79%) were infected by transfusion of blood or blood products. Perinatal transmission occurred in 11 children (13%), and six children (7%) had a history of i.v. drug abuse. The majority of children were asymptomatic at presentation. Of the 65 patients tested for HCV-ribonucleic acid, 43 (66%) were positive. Fifty-seven cases had serial alanine aminotransaminase (ALT) measurements over a mean of 28 months. Of these, 38 (67%) had an abnormal ALT. Ten cases (12%) were co-infected with hepatitis B virus, HIV or both. Of 12 patients treated with interferon, four responded with normalisation of ALT from 3 to 12 months post-commencement of therapy.

CONCLUSIONS

Although HCV was largely an asymptomatic condition in our clinic population, more than half the patients had biochemical evidence of ongoing liver damage. Given the chronicity of this infection in the majority of patients and the long-term risks of cirrhosis and hepatocellular carcinoma, children with HCV infection represent a high-risk group worthy of regular follow up.

Genes for jaundice

The inheritable causes of jaundice comprise a large group of conditions of varying frequency, from Gilbert's syndrome which is relatively common, to the very rare Crigle-Najjar syndrome. Although these conditions have been well characterized clinically and in some cases biochemically, the underlying molecular defects were unknown because of a lack of knowledge about the process of bile secretion by hepatocytes. The recent cloning of several transporters for bile acids and other organic anions has enabled a greater understanding of this process and allowed correlation of the malfunction of these genes with specific disease processes. This new knowledge will provide for precision in diagnosis, allow antenatal testing and provide opportunities for gene therapy for some of the more serious disorders.

Hepatitis G: viroprevalence and seroconversion in a high-risk group of children

Hepatitis G virus (HGV), a recently discovered flavivirus, is parenterally transmitted and significantly associated with hepatitis C viraemia. Data on the viroprevalence of this agent in children is scant and its seroprevalence is unknown. The aim of this study was to determine the viroprevalence and seroprevalence of HGV in paediatric patients at risk of parenterally transmitted virus infection. Sera from 35 patients, previously tested for hepatitis C virus (HCV) infection, were analysed for the presence of HGV RNA by reverse transcription-polymerase chain reaction (RT-PCR) and for antibody to the E2 envelope protein (anti-E2) of HGV using the HGV-env kit. The mean age of the patients was 9.4 years (range 1-17 years), and risk factors included multiple transfusions and maternal HCV infection. Co-infection with HCV and HGV was a relatively common occurrence (31%). The prevalence of anti-E2, a marker of recovery from infection, was low (5%) when compared with overall viroprevalence (20%). This study highlights the significant association of HGV with HCV in children. The novel finding of a low ratio of anti-E2:HGV RNA contrasts with the pattern seen in adults and may reflect a higher risk of long-term carriage with acquisition of HGV infection at an early age.

An unusual cause of rectal bleeding in a patient with cystic fibrosis

Here we identify a previously unreported cause of rectal bleeding (juvenile polyposis) in a patient with cystic fibrosis (CF). We believe this patient most likely has two coexisting genetic diseases. It also raises many issues about organ transplantation in a patient with medical conditions that individually increase the risk of gastrointestinal malignancy and stresses the diagnostic value of endoscopy in CF patients with rectal bleeding.

Hepatic basolateral sodium-dependent-bile acid transporter expression in two unusual cases of hypercholanemia and in extrahepatic biliary atresia

The recent cloning of a human sodium-dependent bile acid transporter (NTCP) permits analysis of its expression in human liver disease and investigation of potential primary defects in its expression. NTCP from normal human liver (NHL) was first characterized in detail. Northern blotting of RNA from NHL revealed a 1.8-kb NTCP transcript. Western blotting of crude NHL plasma membranes using a carboxyterminal antipeptide antibody showed that NTCP is a 39-kd polypeptide that is N-glycosylated to a final molecular weight of 56 kd. Indirect immunofluorescent analysis of NHL sections indicated that the NTCP protein is expressed on the basolateral surface of hepatocytes. We hypothesized that the clinical phenotype of a defect in NTCP might be hypercholanemia in the relative absence of liver disease. Accordingly, the coding region of the NTCP gene of two children with this phenotype was sequenced after reverse transcription/polymerase chain reaction (RT/PCR) amplification. No primary defects in the deduced NTCP amino acid sequence were found. Despite the extremely high serum bile salt levels (235 and 126 micromol/L) in these two patients, NTCP messenger RNA (mRNA) and protein expression were quantitatively normal, in contrast to the published observations in a rat model of cholestasis secondary to common bile duct ligation. Hepatic steady-state NTCP mRNA levels in a group of 23 pre- and postportoenterostomy biliary atresia patients were inversely related to total bilirubin, indicating that extrahepatic bile duct obstruction leads to down-regulation of NTCP mRNA levels, similar to that observed in rat common bile duct ligation. Therefore the lack of down-regulation in the two patients with hypercholanemia indicates that elevated serum bile salts are not sufficient to down-regulate NTCP expression, these two patients have abnormal responses to hypercholanemia, or these two patients have a defect in a gene other than NTCP that influences hepatic clearance of bile salts.

Helicobacter pylori and recurrent abdominal pain in children

Recurrent abdominal pain is one of the most common presentations to pediatricians; yet an organic etiology can be found in only 10% of cases. Because infection with Helicobacter pylori in adults and children results in gastritis, a causative role for the organism has been postulated. To investigate this theory, we conducted a prospective case-control study in children with recurrent abdominal pain using serum H. pylori IgG antibodies measured by an enzyme immunoabsorbent assay. Age, sex, ethnicity, and socioeconomic status were adjusted in the statistical model. Five subjects (5.1%) and 14 controls (14.3%) had raised serum IgG antibodies to H. pylori (adjusted OR, 0.21; 95% confidence interval, 0.05, 0.85). The negative association between H. pylori and recurrent abdominal pain indicates that this organism is unlikely to have an important etiologic role in this disorder.

Prevalence of Helicobacter pylori infection in asymptomatic children

OBJECTIVE

To determine the prevalence of Helicobacter pylori infection in a sample of asymptomatic Australian children.

METHODOLOGY

A prospective observational study, during a 3 month period, of consecutive children aged 0 to 14 years undergoing minor elective surgical procedures in a Day Surgical Unit at a Melbourne paediatric hospital. Subjects without gastrointestinal symptoms or a family history of peptic ulcers had sociodemographic data recorded and serum collected. Serum anti-H. pylori immunoglobulin G antibodies were measured by an enzyme immunoabsorbent assay previously validated in children from the same population.

RESULTS

H. pylori antibodies were present in 21/147 (14.3%) children aged 3 months to 14 years. Prevalence was not influenced by age or sex, but was greatest in children whose parents migrated from developing nations and lowest in children with Caucasian Australian or Western European parents (25.8 vs 5.9%; P < 0.001). An inverse relationship between social class and infection was also observed (P = 0.02). Multivariate analysis demonstrated the father's ethnic background as the only significant independent risk factor for H. pylori infection (P = 0.002).

CONCLUSIONS

Although seroprevalence of H. pylori appears to be lower in Australian children than in developing countries there are some ethnic groups at substantially greater risk for the acquisition of H. pylori infection and its complications.

Differential ontogenic regulation of basolateral and canalicular bile acid transport proteins in rat liver

The hepatic transport systems mediating bile acid uptake and excretion undergo independent, stage-specific expression during development in the rat. In this study, the mechanisms underlying ontogenic regulation of both the Na(+)-dependent basolateral bile acid transporter and canalicular bile acid transporter/ecto-ATPase were examined. Steady state mRNA levels for the basolateral transporter were less than 20% of adult values prior to birth, increased to 35% on the first postnatal day, and reached adult levels by 1 week of age. This was paralleled by transcription rates, which were low prior to birth, reached 47% by day 1, and were maximal by 1 week of age. Steady state mRNA levels for ecto-ATPase were 12% of adult values prior to birth and showed a 2-fold increase by the first day of life. Thereafter, there was a gradual increase in mRNA for this transporter, with adult levels being reached at 4 weeks of age. Transcription rates paralleled this increment, although adult levels were reached earlier. Surprisingly, for both transporters, the full complement of protein was present well before adult levels of mRNA were reached. The basolateral protein was expressed at 82% of adult levels on the first day of life but was of lower apparent molecular mass (39 kDa), a difference that persisted until 4 weeks of age. N-Glycanase digestion suggested that this difference could be fully accounted for by N-linked glycosylation. The ecto-ATPase protein was present at 33% of adult levels prior to birth, 77% by 1 day, and 84% of adult levels by 1 week of age. Unlike the basolateral transporter, the apparent molecular weight of this protein did not change during development. In summary, the ontogeny of bile acid transporters on the plasma membrane of the hepatocyte is complex and appears to be regulated at transcriptional, translational, and post-translational levels.

Cloning and molecular characterization of the ontogeny of a rat ileal sodium-dependent bile acid transporter

Sodium-dependent bile acid transport in the rat ileum is abruptly expressed at weaning. Degenerate oligonucleotides, based on amino acid sequence identities between the rat liver and hamster ileal transporters, were used to amplify a rat ileal probe. A 1.2-kb cDNA clone, which contains the full coding region (348 amino acids, 38 kD), was isolated by hybridization screening. In vitro translation yielded a 38-kD protein which glycosylated to 48 kD. Sodium-dependent uptake of taurocholate was observed in oocytes injected with cRNA. Northern blot analysis revealed a 5.0-kb mRNA in ileum, kidney, and cecum. A 48-kD protein was detected in ileal brush border membranes and localized to the apical border of villus ileal enterocytes. mRNA and protein expression, which were negligible before weaning, increased dramatically at weaning. Nuclear transcription rates for the transporter increased 15-fold between postnatal days 7 and 28. The apparent molecular weight of the transporter also increased between days 19 and 28. In summary, the developmental regulation of the rat ileal sodium-dependent bile acid cotransporter is characterized by transcriptionally regulated increases in mRNA and protein levels at the time of weaning with changes in apparent molecular weight of the protein after weaning.

Multisystem obstruction with cholestasis, pigmentary retinopathy, and cleft palate: a new syndrome?

A number of systemic abnormalities associated with cholestasis have been reported in the literature. This paper describes two unrelated patients with cholestasis and an unusual constellation of abnormalities including cleft palate/lip, hydronephrosis/hydroureter, retinal pigmentation, and intestinal septum.

Helicobacter pylori infection in children

Helicobacter pylori was sought prospectively by culture of antral biopsy, histology and serology (IgG and IgA) in 440 consecutive endoscopies on children to determine the prevalence, clinical presentation and histological features of H. pylori infection in our population. Twenty-eight patients had H. pylori (8% overall). The mean age of infected patients was significantly higher than that of non-infected patients (P less than 0.0001). No patient under 5 years of age had H. pylori isolated. Overall, there was no significant difference in clinical presentation between those with and those without H. pylori infection, but 23% of patients 5 and 26 years of age who presented with abdominal pain as the indication for their endoscopy had H. pylori isolated. Macroscopic changes ranged from no abnormality to frank ulceration, but the typical antral mamilliform changes were 100% predictive of infection. Fifty-eight per cent of patients with duodenal ulcers, but only 17% with gastric ulcers had H. pylori infection. Histological gastritis was present in 144 patients (including all H. pylori positive patients). None of the patients with another definable cause for gastritis had H. pylori isolated. In conclusion, H. pylori is an important cause of primary gastritis in our population, occurring in children over 5 years of age. Culture of an antral biopsy should be performed in children over this age undergoing endoscopy for the investigation of abdominal pain and, more particularly, in those with peptic ulceration.