Germline APC mutations are not commonly seen in children with sporadic hepatoblastoma.

Hepatoblastoma is the most common primary liver tumor in childhood and occurs more commonly in families with familial adenomatous polyposis. Germline mutations of the gene responsible for familial adenomatous polyposis--adenomatous polyposis coli (APC)--are described in patients with hepatoblastoma even without a family history. We investigated children presenting with apparently sporadic hepatoblastoma between 1991 and 2004. Blood samples were available from 29 children (18 boys) whose conditions were diagnosed at a median age of 22 months (range 6-119 months). No germline APC mutations were found, which does not support the need for routine screening in sporadic hepatoblastoma in the absence of a suggestive family history of colorectal cancer or suspicion of familial adenomatous polyposis.

Genetically evolved receptor models: a computational approach to construction of receptor models.

Given the three-dimensional structure of a receptor site, there are several methods available for designing ligands to occupy the site; frequently, the three-dimensional structure of interesting receptors is not known, however. The GERM program uses a genetic algorithm to produce atomic-level models of receptor sites, based on a small set of known structure-activity relationships. The evolved models show a high correlation between calculated intermolecular energies and bioactivities; they also give reasonable predictions of bioactivity for compounds which were not included in model generation. Such models may serve as starting points for computational or human ligand design efforts.

Exploring the experiences of beginning registered nurses entering the acute care setting.

This study begins to explore some of the social and political issues surrounding the practices of the graduate nurse. Utilising an ethnographic methodology with a critical intent, 4 graduate nurses describe their experiences of clinical practice. The major themes raised or issues that were embedded within the nurses' stories revolved around power and control enmeshed within nursing practice. The themes discussed relate to the graduates' perception of their own competence, and the concepts of the ideal nurse, the socialisation of graduates into the ward culture, being on insider or outsider and a good or bad nurse. The resulting discussion utilises the theoretical framework of Foucault's governmentality to suggest ways in which nurses and graduates might make sense of these issues.

Management of intestinal failure.

Intestinal failure (IF) occurs when the body is unable to sustain its energy and fluid requirements without support, due to loss of functional small bowel. Prolonged IF is seen after large intestinal resection and described as short bowel syndrome (SBS). The hallmark of the management is parental nutrition (PN), which is costly and may be associated with the well-recognized problems of parental nutrition associated liver disease (PNALD) and line related sepsis. Cessation of PN at the earliest possible stage is desirable but for this enteral autonomy has to be achieved first. Intestinal adaptation occurs when the remaining gut goes through morphological changes increasing its absorptive capacity. Factors such as intraluminal nutrients, gastrointestinal secretions and hormones facilitate adaptation. Enteral feeds are a potent stimulant to adaptation and should be started as soon as the clinical situation permits. Some drugs are thought to increase intestinal adaptation. These include glutamine, growth hormone and glucagon like peptide- 2, but there is a paucity of pediatric data to guide their use. In some cases surgical bowel lengthening procedures can be performed to increase the absorptive surface area. An isolated liver transplantation may be required if the liver has sustained irreversible damage but intestinal autonomy seems achievable. When prolonged PN is either unsustainable or associated with unacceptable side effects, small bowel transplantation should be considered as a treatment option.

Routine coagulation screening in children undergoing gastrointestinal endoscopy does not predict those at risk of bleeding.

BACKGROUND AND STUDY AIMS: Routine coagulation screening prior to gastrointestinal endoscopy is performed in many centres in the UK, despite the lack of any evidence to support the practice. The aim of this study was to assess the benefits of routine pre-endoscopy coagulation screening in children and to assess how widespread this practice is in the UK. PATIENTS AND METHODS: We performed a retrospective analysis of the case notes of 250 consecutive patients who had undergone routine coagulation screening prior to endoscopy and biopsy, in accordance with our unit's protocol, looking for evidence of abnormal results or episodes of bleeding. We also performed a telephone survey of the protocols for coagulation screening at other paediatric units in the UK which are known to perform gastrointestinal endoscopy on a routine basis. RESULTS: According to our hospital's laboratory reference ranges, 16.8 % of the children who underwent endoscopy and biopsy had abnormal clotting. This was neither clinically significant nor associated with an increased bleeding risk in any patient. Of the 23 UK paediatric gastroenterology centres surveyed, including our own, five (21.7 %) perform routine coagulation screening before endoscopy. CONCLUSIONS: This study suggests that, although it is a relatively common practice, routine coagulation screening is not indicated in children who are undergoing gastrointestinal endoscopy and biopsy, and that it does not predict those at risk of significant bleeding. We would therefore suggest that if pre-endoscopy screening is to be performed, it should be reserved for those who are potentially at high risk of bleeding.

Liver abscesses in children: a single center experience in the developed world.

OBJECTIVES: The aim of this study was to investigate the clinical and radiologic features, predisposing risk factors, and complications of children with pyogenic liver abscess (PLA) referred to a tertiary pediatric hepatology center. METHODS: We analyzed our database of all children referred to our unit over a 10 year period and performed a case note review of all patients with a radiologically proven PLA. RESULTS: PLA was diagnosed in 15 children (7 boys), 0.5% of all referrals. They presented at a median age of 10 years (range 2 months-15 years). In three children (2 boys), PLA was the first manifestation of chronic granulomatous disease. Among the others, five had radiologic evidence of other intra-abdominal pathology (1 with subsequently proven appendicitis), and four developed portal vein thrombosis with portal hypertension. The commonest isolated pathogen was Staphylococcus aureus. Combined treatment with guided aspiration and prolonged intravenous antibiotics was successful in all patients. CONCLUSION: PLA is a rare diagnosis in children in the developed world. It may be caused by primary neutrophil disorders even in the absence of a previous history of infection. Co-existent appendicitis, intra-abdominal sepsis, and ascending pylephlebitis must be sought because these children are at risk of developing portal vein obstruction and portal hypertension. Prolonged intravenous antibiotic treatment guided by microbiologic sensitivities is highly effective.

Variable degree of liver involvement in siblings with PiZZ alpha-1-antitrypsin deficiency-related liver disease.

PiZZ alpha-1-antitrypsin deficiency is the commonest genetic cause of chronic liver disease, but only 10-15% of PiZZ individuals develop liver disease in childhood. Studies have demonstrated varying patterns of disease progression within siblings with the PiZZ phenotype. We retrospectively analysed the case-notes of all patients diagnosed with PiZZ A1ATD between 1978-2002 and compared the pattern of liver disease between affected siblings. We identified 29 families with more than 1 child with the PiZZ phenotype. Twenty-one (72%) PiZZ siblings of the 29 probands had liver disease, which was concordant for severity in 6 (29%), while 8 (28%) had no liver involvement. Five of 7 children requiring liver transplantation had siblings with no persistent liver dysfunction. This study suggests that there is a variable degree of liver involvement in siblings with PiZZ A1ATD-related liver disease and environmental and/or other genetic factors must be involved in determining disease severity.

Adrenal cholesterol esters as substrate source for steroidogenesis.

Adrenocortical cells obtained from tissues of unstimulated rats and which contained a high concentration of endogenous esterified cholesterol, were labeled in vitro with unesterified [4-14C]cholesterol, or incubated in the presence of [2-14C]acetate or lipoprotein [4-14C]cholesterol oleate (LP-CE). Incubations were conducted in the absence and presence of ACTH, and changes in the specific radioactivity (SA) of the secreted corticosterone were used to assess the primary sources of cholesterol substrate used for steroidogenesis. Incubations of cells containing [4-14C]cholesterol with ACTH resulted in a marked increase in the output of corticosterone mass, but not of labeled corticosterone. Thus, the SA of corticosterone when cells were incubated with ACTH was only 6.5% of that obtained from cells incubated in the absence of ACTH. During incubations with [2-14C]acetate, the ACTH-induced increase in the output of corticosterone mass was not associated with increased isotope output, and the SA of corticosterone was only 15% of that in control incubations. This dilution was not altered in cells isolated from adrenals of rats treated with 4-aminopyrazalopyrimidine (4-APP), in which increased cholesterogenesis was demonstrable. The uptake, and hydrolysis of LP-CE, and formation of labeled corticosterone was lipoprotein concentration dependent, and was not influenced by ACTH. However, in the presence of ACTH, the SA of the secreted corticosterone was only 4-8% of that in unstimulated cells. The consistent dilution of the SA of corticosterone in ACTH-treated cells in all studies suggest that the large stores of cytoplasmic cholesterol esters in these cells may normally serve as a primary source of the immediate precursor sterol used for steroidogenesis.

The active site of pyrophosphate-dependent phosphofructo-1-kinase based on site-directed mutagenesis and molecular modeling.

Despite a low level of overall sequence identity between PPi-dependent and ATP-dependent phosphofructo-1-kinases (PFKs), similarities in active-site residues permit a convincing amino acid alignment of these two groups of kinases. Employing recent protein sequence and site-directed mutagenesis data along with the known three-dimensional coordinates of Escherichia coli ATP-dependent PFK, a model of the active site of PPi-dependent PFK was proposed. In addition to providing compatible placement of residues shown to be important by earlier mutagenesis studies, the model predicted an important role for two arginyl residues that are conserved in all known PPi-PFK sequences. Replacement by site-directed mutagenesis of these two residues with neutral amino acids in the PPi-PFK of Naegleria fowleri resulted in a substantial reduction in kcat while not altering the global structure of the enzyme. While the data indicate many similarities in the active-site structures and mechanisms of ATP-dependent and PPi-dependent PFKs, subtle differences, such as the relative roles of Arg residues in the active sites, have evolved in the development of these two subgroups of the PFK family.

ACTH-induced hydrolysis of cholesteryl esters in rat adrenal cells.

Rat adrenal cortical cells have been prepared by collagenase dissociation of trypsin-treated adrenal tissue. The content and compositions of cholesteryl ester, phospholipid, and triglyceride fatty acids compare favorably with those of undissociated rat adrenal tissue. During 2-hour control incubations of adrenal cortical cells, steroidogenesis was not detected, and the levels of sterol ester, phospholipid, and triglyceride fatty acids were not significantly altered. Incubations with adrenocorticotropic hormone (ACTH) resulted in coricosterone production and significant depletions of sterol ester and triglyceride fatty acids, but not of phospholipid fatty acids. Although all fatty acid esters of cholesterol were hydrolyzed under these conditions, the greatest contributions to the net decrease in sterol esters were by oleate, arachidonate, and adrenate. Incubations with dibutyryl cyclic adenosine monophosphate (0.5 mM) resulted in significantly greater levels of corticosterone production than did ACTH (250 muunits), but the effects on cellular lipids were comparable to those seen with the tropic hormone. This study represents the first demonstration of hormone-induced hydrolysis of sterol esters in an in vitro cell suspension system. The results are discussed with respect to hormone-sensitive sterol ester hydrolase of adrenal cortex, and to the role of endogenous cholesteryl esters in the steroidogenic pathway.

Another cause of bloody diarrhoea in infancy: cytomegalovirus colitis in an immunocompetent child.

Although a ubiquitous pathogen, cytomegalovirus (CMV) is very rarely thought to be the cause of significant gastrointestinal infection in the immunocompetent child. We report the case of a 2-month-old infant who presented with bloody diarrhoea and severe dehydration, which was subsequently diagnosed as CMV enterocolitis and resolved spontaneously without antiviral treatment.